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11.
Abstract The aim of this study was to describe the roosts of Nyctophilus bifax in littoral rainforest in Iluka Nature Reserve on the north coast of New South Wales. Radio-telemetry was used to track 17 bats in November 1988 (lactation season) and 11 in May 1989 (mating season) to 87 roosts in 49 trees within the littoral rainforest. The bats frequently changed roosts, which were clustered within a small area. During November, lactating females moved twins between diurnal roosts and some carried twins while foraging. Twins represented a load of up to 95% of their mother's bodyweight. Bats roosted communally in foliage and tree hollows, beneath peeling bark, among epiphytes, and between strangler figs and host trees. Hollows were used more frequently when bats were lactating, while the use of foliage roosts was greater during the mating season. Roosts were concentrated in four tree species, although a wide range of other tree species was used. Roost trees used in November were taller (17m) than those used in May (8. 2 m), and reflect selection of Syzygium leuhmannii and Acmena hemilampra, both trees of the forest interior. The converse applied for selection of Cupaniopsis anacardioides, a small tree of the littoral zone, in May. These results identify the need for conserving a diversity of roosts for this species of bat.  相似文献   
12.
1. Models predicting invasive macrophyte spread between lakes provide an important tool for focusing proactive management efforts to lakes deemed susceptible to invasion. However, challenges to forecasting macrophyte spread include wide physiological tolerances of invasive macrophytes and a lack of information on the relative importance of the various human vectors (e.g. boating traffic). In New Zealand, three invasive species that reproduce vegetatively, Ceratophyllum demersum, Lagarosiphon major, Egeria densa, and a single species that reproduces sexually, Utricularia gibba, are currently spreading across the lake landscape at a great cost to the local ecology and economy. 2. In this study, we first examined whether variables that indirectly describe weed spread via human access and use, as well as a lake’s position in the landscape, could describe the distribution of these four species using a boosted regression trees (BRT) modelling approach. Then, as these invasive species have not reached their full invasion potential, we examined how giving more influence to infected lakes at the edge of the invasion front, and including all lakes across New Zealand as background samples, simulating ‘absences beyond the invasion front’, influenced our ability to forecast the potential for new lakes to be invaded. 3. The BRT models identified that variables characterising human access and use, as well as lake position, were associated with the occurrence of the three vegetatively reproducing macrophytes. Weed occurrence was more likely when there was a highway in the vicinity, human population density was high and if the lake was large (c. 55 km2). But in the single case of U. gibba, temperature was the variable that best explained occurrence. This is consistent with the suggestion that U. gibba is predominantly dispersed by waterbirds, rather than human activity. 4. But for all four species, the BRT models based on the recorded observations alone predicted observed invasions with low prediction probabilities and did not forecast further spread. By contrast, when observations at the edge of the invasion front were upweighted, and additional background lakes implemented into the model, recorded observations were predicted and additional lakes were forecast to be at risk, suggesting that these models better captured the current and potential distribution of these macrophyte species. 5. The use of variables that characterise weed spread could provide similar insights into other systems where survey information on the nature, strength and direction of invasion vectors is lacking. Furthermore, when weighting the data, many lakes across New Zealand were forecasted to be at risk of invasion. The advantage of weighing the presence data was that insights into the potential for a species to spread were obtained. The probabilistic estimates of risk, as derived from the models, together with other information for prioritising lakes, can be used to focus surveillance and protection efforts.  相似文献   
13.
14.
Seed storability is especially important in the tropics due to high temperature and relative humidity of storage environment that cause rapid deterioration of seeds in storage. The objective of this study was to use SSR markers to identify genomic regions associated with quantitative trait loci (QTLs) controlling seed storability based on relative germination rate in the F2:3 population derived from a cross between vegetable soybean line (MJ0004-6) with poor longevity and landrace cultivar from Myanmar (R18500) with good longevity. The F2:4 seeds harvested in 2011 and 2012 were used to investigate seed storability. The F2 population was genotyped with 148 markers and the genetic map consisted of 128 SSR loci which converged into 38 linkage groups covering 1664.3 cM of soybean genome. Single marker analysis revealed that 13 markers from six linkage groups (C1, D2, E, F, J and L) were associated with seed storability. Composite interval mapping identified a total of three QTLs on linkage groups C1, F and L with phenotypic variance explained ranging from 8.79 to 13.43%. The R18500 alleles increased seed storability at all of the detected QTLs. No common QTLs were found for storability of seeds harvested in 2011 and 2012. This study agreed with previous reports in other crops that genotype by environment interaction plays an important role in expression of seed storability.  相似文献   
15.
Northern latitude and upper altitude climatic treelines have received increasing attention given their potential sensitivity to atmospheric and climate change. While greater radial stem growth at treeline sites in recent decades has been attributed largely to increasing temperature, rising atmospheric CO2 concentration may also be contributing to this growth stimulation. Tree ring increments of mature Larix decidua and Pinus uncinata were measured over 4 years in a free air CO2 enrichment experiment at treeline in the Swiss Central Alps (2180 m a.s.l.). In addition, a one‐time defoliation treatment in the second year (2002) of the experiment was used to simulate one of the common natural insect outbreak events. In response to elevated atmospheric CO2, Larix showed a cumulative 4‐year growth response of+41%, with particularly strong responses in the third and fourth year. This increase in radial stem wood growth was the result of more latewood production, in particular, the formation of larger tracheids, rather than a greater number of cells. In contrast, Pinus showed no change in ring width to elevated [CO2], neither in each of the treatment years, nor in the cumulative response over 4 years, although an increase in tracheid size was observed in the third year. Defoliation led to a pronounced decrease in annual ring width of both species, marked in particular by less latewood production, in the treatment, as well as subsequent years. There was no significant interaction between defoliation and CO2 enrichment. Although Pinus showed no growth response to CO2, the positive growth response observed in Larix after 4 years of CO2 enrichment implies that the sensitivity of treeline trees to global change may not be purely temperature driven. We conclude that the open sparse canopy in the treeline ecotone favours the indeterminate growth strategy of the early successional Larix when neither weather nor carbon are limiting, whereas the later successional Pinus does not show any indication of more vigorous growth under future higher atmospheric CO2 concentrations.  相似文献   
16.
Threatening Others: Nicaraguans and the Formation of National Identities in Costa Rica . Carlos Sandoval-García. Athens: Ohio University Press, 2004. 263 pp.  相似文献   
17.
Barriers to the recovery of aquatic insect communities in urban streams   总被引:1,自引:0,他引:1  
1. Worldwide, increasing numbers of stream restoration projects are being initiated to rehabilitate waterways modified by urbanisation. However, many of these projects have limited success in restoring stream communities. Prompted by this, we investigated previously unrecognised barriers to aquatic insect colonisation in urban streams. 2. To investigate whether the availability of suitable substrata for oviposition limited the longitudinal distribution of caddisflies, large boulders were added to the upstream reaches of one stream. Prior to the addition, more egg masses were observed downstream and this longitudinal pattern persisted subsequently. 3. Malaise trapping revealed that adult caddisfly diversity and abundance was greater downstream than upstream. Furthermore, in a previous study the authors found larval caddisflies reflected the longitudinal distribution of adults. 4. The only obvious potential obstructions between reaches were roads beneath which the stream flowed through culverted crossings. Malaise trapping was used to examine the effect of road culverts and bridges on caddisfly dispersal. Numbers of caddisflies caught declined upstream and about 2.5 × more individuals were taken in traps immediately below than above five culverts. 4. Bridges, which had a more open structure than culverts, had no significant effect on the size of catches made above and below them. 5. Road culverts could act as partial barriers to upstream flight, with consequences for larval recruitment in urban streams. We recommend that urban planners and designers of restoration projects consider possible synergistic effects of poor oviposition habitat and barriers to aquatic insect dispersal, which may be critical for the colonisation of urban headwater streams and for the maintenance of stream insect populations.  相似文献   
18.
We developed an alternative method for the determination of 6-n propylthiouracil (PROP) taster status that is based on the comparison of intensity ratings of PROP solutions with intensity ratings of visual, tactile, and kinesthetic (physical) stimuli. We then compared the classification obtained with this method to those derived from traditional approaches. One hundred and forty-two subjects rated the perceived intensity of 0.000032, 0.00018, 0.00032, 0.0018, and 0.0032 M PROP, and 0.01, 0.032, 0.1, 0.32, and 1.0 M NaCl, as well as five levels each of perceived roughness of sandpaper, grayness of shades, and thickness of honey and water mixtures on the Labeled Magnitude Scale (LMS). Ratings for 0.00032 M PROP and 0.1 M NaCl were also compared in a one solution test. Subjects were classified as PROP nontasters, tasters or supertasters by all three procedures. Seventy-six percent of panelists were classified in a similar way by the physical stimuli and NaCl procedures, while 70% percent of panelists were classified similarly by the physical stimuli procedure and the one solution test, as well as by the NaCl procedure and the one solution test. Only 65% of panelists were classified similarly by all three procedures. Further, in replicate ratings of PROP solutions, supertasters' evaluations of PROP at all concentration levels decreased significantly (P < 0.01) from the first to the second rating. It is evident from these findings that the method used to determine PROP taster status can greatly influence the outcome of any investigation of PROP taster status on other phenotypes.  相似文献   
19.
Contemporary U.S. religion is shaped by a new emphasis on bodily and trance experience. This article describes the learning process through which evangelical congregants come to use language and bodily experiences in particular ways, which I call here "metakinesis." Through this process, congregants build remarkably intimate relationships with God.  相似文献   
20.
1. Foraging animals are often faced with foods that vary in several important attributes, some of which may be in conflict with one another. For ectothermic animals, food temperature can be an important characteristic, as the consumption of cold foods is metabolically costly. 2. Here, the effect of food temperature on food preferences in the green‐headed ant Rhytidoponera metallica (Smith, 1858) was investigated. The first aim of the study was to determine how food concentration (caloric value) and relative food temperature influenced colony‐level preferences. We found that, all else being equal, green‐headed ant colonies preferred warmer food solutions over colder solutions, and more concentrated food solutions over less concentrated ones. 3. Next, the question of whether green‐head ant colonies could make trade‐offs between temperature and food concentration was tested. It was found that ant colonies switched their preferences in favour of a colder food solution when the colder food solution was 10 times more concentrated than the warmer food solution. 4. These experiments show that temperature is an important characteristic shaping food preferences in ants. Moreover, we show that colonies can make trade‐offs between food concentration and food temperature.  相似文献   
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