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《Fungal Ecology》2015
Abundance and habitat requirements of nivicolous myxomycetes were surveyed over 4 yr at the northwestern Greater Caucasus ridge (Russia). An elevational transect spanning 3.66 km from 1 700 to 3 000 m a.s.l. was established at the summit Malaya Khatipara situated within the Teberda State Biosphere reserve. Between 2010 and 2013 1177 fructifications of nivicolous myxomycetes were recorded, with 700 of these determined to 44 species, varieties, and forms. Virtually all fructifications developed near or at the margin of a snow field. Abundance of myxomycete fructifications varied extremely between years, ranging from near zero to hundreds of colonies. At sites with known myxomycete occurrences 16 data loggers were installed in the years 2011 and 2012, measuring relative humidity and temperature at the soil surface. Together with weather data recorded on the nearby Klukhor pass and experiments with myxamoebae cultured on agar, these data explain the observed extreme fluctuations in myxomycete abundance. A sudden frost (one night below −10 °C) occurring before the first lasting snow in Nov. 2011 was most likely the reason for the nearly complete absence of myxomycete fruiting in spring 2012. Culture experiments showed that amoebae survived a slow decrease in temperature, as occurs under a sheltering snow cover, but are killed by sudden freezing. Extreme temperature changes recorded at the margin of snow fields explain why nivicolous myxomycetes must fruit before snow melt is complete, and the different transmittance of snow packs for light of different wave lengths may be crucial for triggering the formation of fruiting bodies. The high abundance of fructifications in nivicolous myxomycetes suggests them to be important predators of microbial communities under snow. 相似文献
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Matthew W. Hughey 《Ethnic and racial studies》2013,36(8):1289-1309
This article examines the processes of white racial identity formation in the United States via an examination of a white nationalist organization and a white antiracist organization. Findings indicate that the construction of white racial identity in both groups is based on the reproduction of various racist and essentialist ideologies. The realization that there is a shared ‘groupness’ to outwardly different white identities has the potential to destabilize the recent trend that over-emphasizes white heterogeneity at the expense of discussion of power, racism and discrimination. As a resolution to this analytic dilemma, this article advances a conceptual framework entitled ‘hegemonic whiteness’. White identity formation is thereby understood as a cultural process in which (1) racist, reactionary and essentialist ideologies are used to demarcate inter-racial boundaries, and (2) performances of white racial identity that fail to meet those ideals are marginalized and stigmatized, thereby creating intra-racial distinctions within the category ‘white’. 相似文献
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《Comptes Rendus Palevol》2002,1(6):335-345
D’Orbigny’s stratigraphic contributions were enormous, both practical and theoretical. In his practice, d’Orbigny realised the central importance of using fossil faunas to correlate strata across different countries. His ‘succession chronologique des âges du monde’ (of 1852) recognised 5 periods and 27 stages (ignoring his ‘époque actuelle’). The great majority of the latter were from two Periods, Jurassic (stages 7 to 16) or Cretaceous (17 to 23). D’Orbigny described the palaeontological characteristics, and geographical extensions, of each. Some stages he based on countries he never visited and although he never specified ‘stratotype’ localities, he referred to some as ‘étalon’, ‘le mieux’ or ‘le plus beau’. These leads proved crucial when, in the mid 20th century, stratigraphers realised that definitions of chrono-stratal units must be attempted. The first attempts at typification simply followed zoology, where a type specimen tries to define a central position within the morphological variation of a species. In 1962, an early attempt was made to define Jurassic stages by three type horizons at different type localities (or stratotypes as they were now called) for each. A central horizon was chosen as ‘lectotype section’ and upper and lower boundaries for each were defined elsewhere. In France, it was preferred to investigate original intentions at named localities, through unit-stratotypes. These allowed some nationalistic pride, since France was the home of so many d’Orbignyan stages. 1980 saw the publication Les Étages français et leurs Stratotypes. However, British Silurian stratigraphers had realised that such zoologically based concepts would produce conflict, when any defined upper boundary stratotype conflicted with the defined lower boundary of a superjacent unit. They suggested, from 1962, to define only lower boundaries, via ‘golden spikes’, at basal-boundary stratotypes. This was the method chosen for the basal Devonian stratotype at Klonk, Czech Republic, defined in 1972, and a method adopted globally from 1986. However, this was when correlations were still largely based on fossils. The explosion of so many other stratigraphies since, based on magnetic or chemical records, events etc, has produced a first reaction against the idea that such stratotypes should be so defined, while a second, potentially more major claim, is that any ‘golden spike’ concept may no longer ‘glitter’, as competing stratotype concepts may be holding back stratigraphic progress. 相似文献
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Abstract Are predictions that Hispanics will make up 25 per cent of the US population in 2050 reliable? The authors of this paper argue that these and other predictions are problematic insofar as they do not account for the volatile nature of Latino racial and ethnic identifications. In this light, the authors propose a theoretical framework that can be used to predict Latinos’ and Latinas’ racial choices. This framework is tested using two distinct datasets – the 1989 Latino National Political Survey and the 2002 National Survey of Latinos. The results from the analyses of both of these surveys lend credence to the authors’ claims that Latinas’ and Latinos’ skin colour and experiences of discrimination affect whether people from Latin America and their descendants who live in the US will choose to identify racially as black, white or Latina/o. 相似文献
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《Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences》2013,44(3):316-326
For decades historians of science and science writers in general have maintained that Charles Darwin was not the ‘naturalist’ or ‘official naturalist’ during the 1831–1836 surveying voyage of HMS Beagle but instead Captain Robert FitzRoy’s ‘companion’, ‘gentleman companion’ or ‘dining companion’. That is, Darwin was primarily the captain’s social companion and only secondarily and unofficially naturalist. Instead, it is usually maintained, the ship’s surgeon Robert McCormick was the official naturalist because this was the default or official practice at the time. Although these views have been repeated in countless accounts of Darwin’s life, this essay aims to show that they are incorrect. 相似文献
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Nadia Mohamadi Messaouda Meraghni Asma Necib Loubna Jelaiel Mehdi El Arbi Mohamed Bouaziz 《化学与生物多样性》2023,20(3):e202200596
The effluents derived from the processing of table olives stand for a serious environmental problem. The study aims to valorize the brine water of table olives at different stages of ripening (green and black) of the Algerian variety Sigoise of Bejaia (East) and Mascara (West). The physico-chemical characterization revealed that these samples display have a high acid pH and salinity. The comparative study of phenolic levels exhibited showed very significant differences between the brine waters of green olives from Bejaia and Mascara, while the brines of black olives presented showed comparable levels. A high strong antioxidant potential was confirmed by DPPH (CI50=0.35 μg/100 ml–0.50 μg/100 ml) and FRAP (CI50=626.89 μg/100 ml–875.54 μg/100 ml) tests. Chemical screening by HPLC-DAD of the four samples identified high concentrations of hydroxytyrosol (HT) (390.4 mg/100 ml–360.8 mg/100 ml) and tyrosol (202.2 mg/100 ml–101.4 mg/100 ml). This study provided a deeper insight into the phenolic profile and the antioxidant potential of these brines. 相似文献
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We describe a new lizard taxon, Stefanikia siderea gen. et sp. nov., from the early-middle Eocene locality of Messel in Germany based on a nearly complete skeleton, which we studied using μCT methods. It shares many characters with the Eocene taxon Eolacerta, which is broadly distributed in the Eocene of central and Western Europe, but is much smaller and shows several important anatomical differences. The new discovery sheds light on the paleodiversity of these lizards in the Eocene of Europe, and the new family name Eolacertidae is proposed to encompass Eolacerta and Stefanikia. The relationships of Eolacerta have been intractable. Our phylogenetic analyses confirm that Eolacertidae is a member of the clade Lacertiformes and provide strong support for a sister-group relationship to Lacertidae. In some places, skin impressions are preserved, displaying the body scalation. As such, the exquisitely preserved specimens of Eolacertidae from Messel provide new insight into the morphology and ecology of lizards on the stem of Lacertidae, Europe’s dominant group of living reptiles.
http://zoobank.org/urn:lsid:zoobank.org:pub:DFD01563-A913-4286-B64B-E0912474FD08 相似文献
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James Mittra 《New genetics and society》2013,32(2):159-179
In light of a recent House of Commons Select Committee investigation into the regulation of human reproductive technologies, this article critically evaluates the Committee's case for a devolved, libertarian-inspired framework for the regulation of reproductive technologies. In assessing the appropriate balance between legislation, regulation and reproductive freedom, the Committee rightly challenged those who exhibit a myopic history of eugenics to justify restricting reproductive choice. However, by uncritically embracing the tropes of procreative liberty and genetic progress, and defining eugenics in terms of intention rather than consequence, the Committee appeared to ignore or marginalise a number of sociological challenges to the presumptions couched within the doctrine of ‘liberal choice’. This article suggests that failure to consider the cultural and political context within which new technologies are shaped and social needs constructed might undermine any ostensible virtues of a devolved system of governance for reproductive medicine. 相似文献
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Mankind has observed and documented life cycle stages of plants and animals for a long time. However, it was comparatively
recently that the newly emerging science was given its name. The name of Charles Morren and the year 1853 are being cited,
although not frequently. Exact information is hardly known among present-day phenologists, yet new evidence shows that the
term “phenology” was already in use in 1849. In the early 1840s, physicist and astronomer Adolphe Quetelet set up an observational
network named "Observations of periodical Phenomena of the Animal and Vegetable Kingdom” and issued instructions for it. Even though biologist Charles Morren welcomed Quetelet's initiative, differences between
Morren and Quentlet regarding the instructions for the observations and the potential results soon arose and a debate started,
which lasted for nearly 10 years. In the wake of these disagreements, Morren was compelled to create a new term to denote
his ideas on “periodical phenomena”. At first, he temporally used the word anthochronology, but in the end he coined the word phenology. The term was first used in a public lecture at the Académie royale des Sciences, des Lettres et des Beaux-Arts de Belgique’ in Brussels on 16 December 1849, and simultaneously in the December 1849 issue of volume V of the Annales de la Société royale d’Agriculture et de Botanique de Gand. One had to wait until 1853 before the new name appeared in the title of one of Morren’s publications. Based on evidence
from archives and original publications, we trace the 10-year-long scientific debate between Morren and Quetelet. Morren states
his biologist’s view on the subject and extends the more climate-related definition of Quetelet of “periodical phenomena”. 相似文献
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Isabella Piga Stefano Casano Andrew Smith Silvia Tettamanti Davide Leni Giulia Capitoli 《Expert review of proteomics》2013,10(11):937-948
ABSTRACT Introduction: An accurate diagnostic classification of thyroid lesions remains an important clinical aspect that needs to be addressed in order to avoid ‘diagnostic’ thyroidectomies. Among the several ‘omics’ techniques, proteomics is playing a pivotal role in the search for diagnostic markers. In recent years, different approaches have been used, taking advantage of the technical improvements related to mass spectrometry that have occurred. Areas covered: The review provides an update of the recent findings in diagnostic classification, in genetic definition and in the investigation of thyroid lesions based on different proteomics approaches and on different type of specimens: cytological, surgical and biofluid samples. A brief section will discuss how these findings can be integrated with those obtained by metabolomics investigations. Expert commentary: Among the several proteomics approaches able to deepen our knowledge of the molecular alterations of the different thyroid lesions, MALDI-MSI is strongly emerging above all. In fact, MS-imaging has also been demonstrated to be capable of distinguishing thyroid lesions, based on their different molecular signatures, using cytological specimens. The possibility to use the material obtained by the fine needle aspiration makes MALDI-MSI a highly promising technology that could be implemented into the clinical and pathological units. 相似文献
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Keishi Abe Yoichi Otsuka Minoru Yasujima Satoru Ciba Masahide Seino Nobuo Irokawa Kaoru Yoshinaga Fumio Hirata Shiro Ohki Nobuhiko Nakazawa Toshio Hanyu 《Prostaglandins & other lipid mediators》1976,12(5):843-848
The excretion rates of main urinary metabolite of PG F2α were measured radioimmunologically in 4 healthy persons and in 13 essential hypertensives. The resting values were 9.3±0.73 in the former and 10.4±2.17 ng/min in the latter. There was no significant differences between them. The excretion of the metabolite decresed prominently after the administration of furosemide. The percent decrease was 57% in healthy persons and 70% in essential hypertension. The percent result supports that furosemide inhibit the catabolism of PG F2α. 相似文献
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Due to the considerable losses caused by slugs in terms of agricultural production and revenue, there is an urgent need for a cost effective biological control agent. The malacophagous nature of the sciomyzid fly, Tetanocera elata (Fab.) makes it a possible contender to meet this demand. This study examined the effect of constant temperatures (14, 17, 20, 23, and 26 °C), in addition to ambient outdoor and laboratory temperatures on T. elata larval duration and predation. In general, the mean and median larval stage duration decreased as temperature increased with percentage survival for the overall larval stage (62%) greatest at 20 °C with a median duration of 44 days. There was no significant difference between temperatures with regard to the number of slugs killed per larva and while predation rate increased with increasing constant temperature, there was also no significant difference between the constant temperatures. Our results show that puparial weight can be used to predict the sex of adult flies prior to their emergence. The results are discussed in the context of the suitability of T. elata as a biological control agent of pestiferous slugs. 相似文献
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Anna Maria Mercuri Carla Alberta Accorsi Marta Bandini Mazzanti Giovanna Bosi Andrea Cardarelli Donato Labate Marco Marchesini Giuliana Trevisan Grandi 《Vegetation History and Archaeobotany》2006,16(1):43-60
The paper presents a synthesis of the on-site archaeobotanical investigations of the Terramara di Montale, one of the most important sites of the Terramara cultural system which characterised the Po Plain in the Middle-Late Bronze Age (1650–1200 b.c.). Samples for pollen analysis and macroremains, including seed/fruit and wood/charcoal records, were collected from stratigraphic sequences and occupation levels during the excavations 1996–2001. The results permitted the reconstruction of the main characteristics of the landscape which at the onset of the Terramara rapidly passed from a natural, more forested landscape with mixed oak wood and conifers to a more open and anthropic landscape characterised by cereal fields, pastures and meadows. People felled oaks and other trees such as Populus/Salix and Fraxinus to make piles or walls for houses. Wood from these species was also recorded as charcoal in the hearths. Palynological and carpological data show that the inhabitants of the Terramara largely founded their economy on cereals (mainly Triticum aestivum/durum, T. dicoccum and Hordeum vulgare). They also grew a few legumes (Vicia faba var. minor, Vicia sp. and Lens culinaris). There was also grazing by domestic animals, mainly ovicaprines but also pigs and cattle, and these were fed exploiting wild plants such as Carpinus. In the paper the four main steps of the history of the Terramara are described (before the Terramara, the onset, the Terramara phase, the decline) during which both human influence and climatic changes were important. At the onset of the Terramara (around 1600 b.c.) a warm and possibly dry phase occurred. The intense use of the territory and a climatic deterioration at around 1300 b.c. might have triggered the decline of the Terramara di Montale. 相似文献
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Karen H. Støverud Martin Alnæs Hans Petter Langtangen Victor Haughton 《Computer methods in biomechanics and biomedical engineering》2016,19(6):686-698
Syringomyelia, fluid-filled cavities within the spinal cord, occurs frequently in association with a Chiari I malformation and produces some of its most severe neurological symptoms. The exact mechanism causing syringomyelia remains unknown. Since syringomyelia occurs frequently in association with obstructed cerebrospinal fluid (CSF) flow, it has been hypothesized that syrinx formation is mechanically driven. In this study we model the spinal cord tissue either as a poro-elastic medium or as a solid linear elastic medium, and simulate the propagation of pressure waves through an anatomically plausible 3D geometry, with boundary conditions based on in vivo CSF pressure measurements. Then various anatomic and tissue properties are modified, resulting in a total of 11 variations of the model that are compared. The results show that an open segment of the central canal and a stiff pia (relative to the cord) both increase the radial pressure gradients and enhance interstitial fluid flow in the central canal. The anterior median fissure, anisotropic permeability of the white matter, and Poisson ratio play minor roles. 相似文献