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11.
Abstract: We studied the behavioral effects of necklace-style radiotransmitters on breeding male western burrowing owls (Athene cunicularia hypugaea) in 2 areas of northwestern Texas, USA, in 2004 and 2005. We tested the hypothesis that transmittered owls would spend time interacting with their necklaces and as a result spend less time in vigilance and resting activities than would nontransmittered owls. Nontransmittered owls (n = 6) spent significantly more time being vigilant (P = 0.007) than did transmittered owls (n = 3) in 2004, who spent significant amounts of time interacting with their necklaces. In 2005, behaviors of transmittered owls (n = 8) were significantly different (P < 0.001) from control individuals (n = 4), but behaviors did not vary consistently by treatment period (prenecklace vs. necklace vs. postnecklace periods). Behavioral activity budgets varied considerably among individuals. Although the owls spent a significant amount of time interacting with their necklaces, they appeared to habituate to the presence of the transmitters within a relatively short period (<1week), and necklaces did not affect survivorship or fitness in the short-term.  相似文献   
12.
Abstract: The focus of digital photography has moved from documentation to quantitative analysis. To illustrate the potential application of this diagnostic tool to quantify color and shape, we photographed both artificial and natural semipalmated plover (Charadrius semipalmatus) nests to determine what benefits, if any, were derived from egg crypsis (i.e., eggshell color and egg marking shape). This simple and cost-effective method provides precise and repeatable quantification of color and shape that discriminated subtle differences in egg crypsis of artificial and natural nests that were not visible to us. The advantages of digital photography and image-editing software outweigh any shortcomings, as long as standard protocols are followed for capturing and analyzing images. Used with due care, digital photography is useful in studies that need to quickly assign biological traits, such as age and sex, to individuals, and to document temporal change that may occur as a response to management or disturbance.  相似文献   
13.
When multiple ornaments are expressed in both sexes, they are generally assumed to be maintained by mutual sexual selection and have a function in mate choice. In the Long‐tailed Finch Poephila acuticauda both sexes exhibit multiple ornaments that vary in their expression in either size (pintail and throat patch) or colour (bill) between individuals and sexes. We assessed whether these ornaments are maintained by mutual sexual selection by exploring whether individuals in a wild population paired assortatively with respect to these ornamental traits, and the degree to which the expression of these ornamental traits was indicative of reproductive success. We found no evidence of assortative pairing with respect to variation in homologous ornaments or body condition in the two sexes. In addition, we found no effect of ornament expression on the reproductive success of either males or females. Our findings suggest that the expression of these apparently ornamental traits in both sexes of this species may play no current role in mutual mate selection or as indicator traits of reproductive performance. We are currently unable to identify any function for these very elaborate ornaments in either sex of this species and suggest that the typical assumption that all such traits have an ornamental function may need further examination.  相似文献   
14.
Religion and Healing in America. Linda L. Barnes and Susan S. Sered, eds. New York: Oxford University Press, 2005. 535 pp.  相似文献   
15.
We characterized eight polymorphic microsatellites in the Scotia icefish Chaenocephalus aceratus (Perciformes, Notothenioidei, Channichthyidae) that is endemic of Southern Ocean waters surrounding the tip of the Antarctic Peninsula. Microsatellites were isolated from a partial genomic library enriched for an AC motif. The number of alleles ranged from two to 19 with a mean observed hererozygosity of 0.71. Loci were in Hardy–Weinberg equilibrium and no evidence for linkage disequilibrium was found. These molecular markers will be useful to investigate Scotia icefish genetic structure, possibly providing insights on its effective population size and demographic history.  相似文献   
16.
This essay unpacks the complex emergence of video indígena , or state-sponsored small media, at the height of official pluralism in Mexico in the early 1990s. A government video program created in a transitional institutional setting colludes with the indigenous autonomy movement---through the work and visions of individual video makers and cultural activists---to produce a social form and process that has gained international recognition while confronting particular challenges in indigenous communities.  相似文献   
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Species discovery through large‐scale sampling of mitochondrial diversity, as advocated under DNA barcoding, has been widely criticized. Two of the primary weaknesses of this approach, the use of a single gene marker for species delineation and the possible co‐amplification of nuclear pseudogenes, can be circumvented through incorporation of multiple data sources. Here I show that for taxonomic groups with poorly characterized systematics, large‐scale genetic screening using a mitochondrial DNA marker can be a very effective approach to species discovery. Global sampling (120 locations) of 1295 individuals of 22 described species of eucalanid copepods identified 15 novel evolutionarily significant units (ESUs) within this marine holoplanktonic family. Species limits were tested under reciprocal monophyly at the mitochondrial (mt) gene 16S rRNA, and 13 of 15 lineages were reciprocally monophyletic under three phylogenetic inference methods. Five of these mitochondrial ESUs also received moderate support for reciprocal monophyly at the independently‐inherited nuclear gene, internal transcribed spacer 2 (ITS2). Additional support for the utility of mt DNA as a proxy for species boundaries in this taxon is discussed, including results from related morphological and biogeographic studies. Minimal overlap of intra‐ESU and inter‐ESU 16S rRNA genetic distances was observed, suggesting that this mt marker performs well for species discovery via molecular screening. Sampling coverage required for the discovery of new ESUs was found to be in the range of >50 individuals/species, well above the sampling intensity of most current DNA Barcoding studies. Large‐scale genetic screening can provide critical first data on the presence of cryptic species, and should be used as an approach to generate systematic hypotheses in groups with incomplete taxonomies.  相似文献   
19.
Colonization of novel habitats is often associated with differences in ecological community composition. For small diurnal animals, differences in predator diversity and abundance can lead to behavioural shifts in the novel habitat. The eastern fence lizard Sceloporus undulatus (Bosc and Daudin, 1801) recently colonized the gypsum dunes of White Sands, a predator‐poor community relative to the predator‐rich community of the surrounding Chihuahuan dark‐soil habitat. We used field experiments to assess S. undulatus anti‐predator behaviour in white‐sand versus dark‐soil habitats, and used laboratory assays to determine whether behavioural differences could be mediated by hormonal regulation. Overall, we found that white‐sand lizards were less vigilant but more wary than their dark‐soil counterparts; it took them longer to detect a simulated predator, but once detected they were more likely to retreat from their perches than dark‐soil lizards. At the proximate level, differences in anti‐predator behaviour could not be explained by differences in plasma hormone levels (corticosterone and testosterone); we detected elevated corticosterone for lizards in our stress treatment relative to control treatment, but found no differences between habitats in baseline or acute corticosterone levels. At the evolutionary level, we suggest that differences in anti‐predator behaviour may be explained by differences across habitats in predation environment, habituation, and/or the cost of retreating. Our study implicates changes in predator community composition in mediating ecological divergence in behaviour. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 657–667.  相似文献   
20.
When the epicotyls of etiolated 7 d pea seedlings were illuminated,there was a rapid rise in the lignin content of the apical shoot(consisting of the third internode with its terminal bud), togive a 10-fold increase after 24 h; there was no change in theunilluminated controls. About 80% of the lignin in the apicalshoot was found in the stem internode, both before and afterillumination. Over this period, the activities of phenylalanineammonia-lyase, cinnamate 4-hydroxylase, and 4-coumarate: CoAligase increased co-ordinately up to five times those of thedark controls over 12 h, when lignification was most rapid,and then declined to about half their maximum activity. Allthree enzymes showed the same 1.5 h lag period before increasing.By comparison, no increases were observed in the later enzymesof lignin biosynthesis, namely S-adenosylmethionine: caffeateO-methyltransferase, cinnamoyl-CoA reductase, NADP+-cinnamylalcohol dehydrogenase, and cell-wall peroxidase, but the proportionsof these enzymes in buds and stem internodes were close to thedistribution of lignin between them, both before and after illumination.Two forms of 4-coumarate: CoA ligase were found; despite theirdifferent activities and substrate specificities, both formsshowed substantial changes. The results suggest that lignogenesisis initiated by an increase in the activities of the three enzymesof general phenylpropanoid metabolism in cells already containingenzymes catalysing the later stages of lignin synthesis; theyare discussed in relation to biochemical and anatomical differentiationwithin plant organs generally. Key words: Lignification, pea shoots, phenylalanine ammonia-lyase, phenylpropanoid enzymes, Pisum sativum  相似文献   
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