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1.
Palynology, which is the study of pollen and spores in an archaeological or geological context, has become a well-established research tool leading to many significant scientific developments. The term palynomorph includes pollen of spermatophytes, spores of fungi, ferns, and bryophytes, as well as other organic-walled microfossils, such as dinoflagellates and acritarches. Advances in plant genomics have had a high impact on the field of forensic botany. Forensic palynology has also been used and applied more recently to criminal investigation in a meaningful way. However, the use of pollen DNA profiling in forensic investigations has yet to be applied. There were earlier uses of dust traces in some forensic analyses that considered pollen as a type of botanical dust debris. Pollen grains can be studied for comparative morphological data, clues to unexpected aspects relating to breeding systems, pollination biology and hybridization. This can provide a better understanding of the entire biology of the group under investigation. Forensic palynology refers to the use of pollen and other spores when it is used as evidence in legal cases to resolve criminal issues by proving or disproving relationships between people and crime scenes. This overview describes the various contributions and the significance of palynology, its applications, different recent approaches and how it could be further employed in solving criminal investigations.  相似文献   

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A karyomorphological study of two species in Asteropyrum (Ranunculaceae) and five in presumably related genera (one each in Caltha , Coptis , and Dichocarpum and two in Thalictrum ) reveals close similarities between Asteropyrum and Caltha , but obvious differences between Asteropyrum and Coptis , Dichocarpum , and Thalictrum , in some karyological features, such as the structure of the interphase nuclei, chromosome size, basic chromosome number, and condensation behaviour of chromosomes during the mitotic prophase. The chromosomes of Asteropyrum are categorized as being of the R-type and the basic chromosome number is confirmed as x  = 8, indicating a possible close affinity of Asteropyrum to members in the subfamily Helleboroideae, in particular to Caltha and its allies. Asteropyrum peltatum and Asteropyrum cavaleriei are shown to be more or less differentiated from each other in gross morphology and palynology, and somewhat independent in geographical distribution, albeit with intermediate forms occurring where their distribution zones overlap. It seems justifiable to treat them as two subspecies of A. peltatum .  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 15–26.  相似文献   

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Our research on chlorophyll biosynthesis, over a period of approximately twenty years, has been described, emphasizing those areas in which our laboratory made significant and timely contributions. References to some of our most important articles are included. Portions of the chlorophyll biosynthetic pathway, in which our own laboratory was not involved, for example, the reduction of protochlorophyllide to chlorophyllide and the phytylation of the latter to yield chlorophyll a, have not been covered in this article. Those events which preceded my involvement with chlorophyll biosynthesis, but which contributed to the formation of my own scientific personality, are mentioned briefly in the Introduction. My non-scientific avocations have been included at the request of the reviewers and Govindjee.  相似文献   

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ABSTRACT

In the spirit of ‘furthering debate and reflection’ in this response to Theories of Race and Ethnicity, we consider here the pertinence of the theme of resistance that occupies particular chapters within the collection and that has been central to key works within the wider race critical scholarship. Yet, when the larger field of contemporary race study is considered, we also note that other contiguous concerns – including capitalism, religion, nation, and war – are key factors in thinking through racism. Here, we further elaborate on how future theorizations of race and ethnicity must engage with these domains.  相似文献   

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This paper reviews the achievements of Abbott Handerson Thayer (1849–1921), an American painter and naturalist whose pioneering writings on animal camouflage addressed shared concerns among artists, zoologists and military tacticians. It discusses his beliefs about camouflage (both natural and military) in the context of his training as an artist, with particular emphasis on three of his major ideas: countershading, ruptive (or disruptive) coloration and background picturing.  相似文献   

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The recognition of species proceeds by two fairly distinct phases: (1) the sorting of individuals into groups or basic taxa (‘discovery’) (2) the checking of those taxa as candidates for species-hood (‘justification’). The target here is a rational reconstruction of phase 1, beginning with a discussion of key terms. The transmission of ‘meaning’ is regarded as bimodal: definition states the intension of the term, and diagnosis provides a disjunction of criteria for recognition of its extension. The two are connected by a spectrum, with purely theoretical definition at one pole and purely ‘operational’ diagnosis at the other, with the more operational elements explained by the more theoretical. The current plethora of species concepts provides a good example. Accepting the Ghiselin–Hull thesis, that a species is an individual, a basic taxon is therefore also an individual with organisms as its parts. In a generalised synchronic individual its parts are conceptually integrated by an integrating principle (IP), which consists of a relation applying within a plan or rule. Fully developed, such an IP ensures the maximisation of the information content of the individual. A diachronic individual is then the set of its component synchronic parts, and its IP is provided by near-identity in an appropriate space-time (not necessarily physical). The integration of parts of an individual is illuminated by Gasking's concept of a proper group (in this case a chain-group), whose members are related by the relation serially fitting together with, the IP completed by an appropriate plan or rule. Gasking also applied the term cluster to a proper group persisting over a substantial period of time, individuated by any member acting as focus. A basic taxon is therefore a cluster of individuals, integrated by the relation significantly taxonomically similar and the rule in character-space-time. The nature of those concepts is discussed and defended. A species will inherit certain of the attributes of the preceding basic taxon (taxa). In at least the synchronic version its parts (individuals) will resemble each other significantly, providing the intuitive applicability of ‘members of’ and ‘instances of’ a species. Also, the notion that a species’ name is given by pure ostension, via a name-bearer (holotype) is empirically incoherent: the name cannot be applied in practice without an appropriate set of diagnostic traits.  相似文献   

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The role of the Nobel Laureate Henry Dale (1875–1968) in the history of allergy and the association of anaphylactic conditions with the liberation of histamine is often overlooked. This paper examines his work in this field in the broader context of his researches into endogenous mediators of normal physiological and abnormal pathological functioning. It also assesses the impact of his working environment, especially the unique conditions he enjoyed at the beginning of the twentieth century in the Wellcome Physiological Research Laboratories (WPRL). The WPRL belonged to the pharmaceutical manufacturer Henry Wellcome, and it was the juxtaposition of the routine commercial obligation of testing drugs for Burroughs, Wellcome & Co., with the opportunities of pursuing unfettered physiological research in well-equipped and supported laboratories, that resulted in what Dale referred to as ‘happy accidents’ when one set of results suggested experimental strategies and designs to another circumstance. In this way an observation of an unusual effect of an extract of ergot of rye led to collaborative chemical and physiological explorations which revealed the presence of histamine, previously known only as a synthetic product. Further work, accidentally facilitated by the fact that the WPRL produced serum anti-toxins commercially and surplus horse serum was used in experiments where other physiologists routinely used saline, hinted that histamine played a role in the symptom complex known as anaphylaxis. This paper explores some of these themes and elaborates their significance.  相似文献   

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由于优异安全性和有效性数据,结合疫苗已成为细菌性疫苗研制的一个方向,但因不同团体独立研发,产生了不同的结合技术,也带来了一些困惑。通过对几个具有代表性的结合疫苗研发团队的研究历程的回顾,探讨了结合方法、载体蛋白质、剂型等热点话题,以期对结合疫苗的研制有所帮助。  相似文献   

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Evolutionarily stable strategies or ESSs of games among kin have been calculated in the literature by both personal-fitness and inclusive-fitness methods. These methods were compared by Hines and Maynard Smith (1979) for games with bilinear payoffs. Although Hines and Maynard Smith regarded the first method as correct, they regarded the second method as useful because the inclusive-fitness conditions for an ESS gave necessary conditions for a personal-fitness ESS in the class of games they considered. In general, however, satisfying the inclusive-fitness conditions is neither necessary nor sufficient for satisfying the personal-fitness conditions, although the two methods may often yield identical ESSs. This result is established by reformulating the classic war-of-attrition model to allow variation in energy reserves, assumed to have a Gamma distribution. For this game, the two methods may disagree for intermediate values of relatedness. By the correct method, if the coefficient of variation in energy reserves is sufficiently high, then the game has a unique ESS in pure strategies at which populations with higher coefficients of variation or relatedness display for shorter times. Unrelated contestants are prepared to expend at least half of their reserves. For populations with lower variation coefficients, the ESS exists only if the cost of displaying per unit time is low compared to the rate at which remaining reserves translate into expected future reproductive success for the victor. The critical variation coefficient, below which the ESS exists regardless of cost, decreases from 0.52 to 0 as the coefficient of relatedness increases from 0 to 1. Although there is no assessment, contests are always won by the animal with greater energy reserves in a population at the ESS.  相似文献   

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The neotropical genera Brownea and Browneopsis are understorey trees and shrubs of lowland rain forest comprising twelve and six species, respectively. Four species of Brownea and three of Browneopsis occur in Ecuador. Keys to the genera and species in Ecuador are provided, and Brownea coccinea, B. grandiceps, B. macrophylla, B. multijuga, Browneopsis disepala, B. ucayalina , and B. macrofoliolata are described, the last-named as a new species. Additionally, the intergeneric relationships, and the morphological and the palynological variation in the genera are surveyed.  相似文献   

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The author presents the Academie de Médecine de France its structure, its history and its fundamental activities. He evokes and proposes some ideas about the medical problems concerning Tunisia and countries of Maghreb.  相似文献   

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