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991.
A technique is described whereby 5th‐instar larvae of the codling moth (Laspeyresia pomonella) which have finished feeding can be tagged externally with cobalt‐58 and released on apple trees, where they seek cocooning sites. Two μCi 58Co per insect did not significantly affect larval survival in the field, or subsequent pupation, emergence, mating, and oviposition in the laboratory. Tagging was more efficient than whole‐tree scraping for the location of cocoons, and was non‐destructive of both the insects and their cocooning sites.

Relocation and observation of the tagged larvae in their cocoons permitted accurate estimation of mortality from when they left the fruit (= release) until adult emergence in the following spring. Natural mortality of larvae seeking cocooning sites was attributed mainly to insect predators, and varied significantly between trees and blocks, averaging 57% over 6 years. Avian predation by the silvereye (Zosterops lateralis) was the greatest hazard to cocooned larvae; this, too, varied significantly between blocks, and averaged 53% over the same period. Both mortalities appeared to be density‐related.  相似文献   
992.
A theoretical model discussing the environmental factors (EFs) effect of exposure time on genes, which leads to human diseases, is presented using multi-logistic model. The advantages and limitations of this model are discussed in terms of its usefulness for simulating genetic samples. It has been shown that EFs affect genes with the same degree both at high exposure level, low exposure time and at low exposure level, high exposure time.  相似文献   
993.
Corrosion and biofouling phenomena of cast iron and brass were evaluated under natural conditions to determine the degradation process of archeological artifacts. Field exposure studies of experimental materials were conducted over 15 months at an offshore position in the sea of Campeche in the Gulf of Mexico. Corrosion was determined by gravimetric measurements. The community structure of the benthic assemblage inhabiting the surfaces of both materials was evaluated. A total of 53 species was identified. The community in both cases was composed of a small number of species. Encrusting, attached and erect life forms were dominant on iron. Attached life forms were dominant on brass. Biofouling produced a decrease in the weight loss measurements of cast iron samples. Biofouling provided a beneficial factor for in situ preservation of iron archeological artifacts in wreck sites.  相似文献   
994.
Marine biofilm communities that developed on artificial substrata were investigated using molecular and microscopic approaches. Polystyrene, Teflon® and four antifouling (AF) paints were immersed for 2 weeks at two contrasting sites near Toulon on the French Mediterranean coast (Toulon military harbour and the natural protected area of Porquerolles Island). Biofilms comprising bacteria and diatoms were detected on all the coatings. The population structure as well as the densities of the microorganisms differed in terms of both sites and coatings. Lower fouling densities were observed at Porquerolles Island compared to Toulon harbour. All bacterial communities (analysed by PCR-DGGE) showed related structure, controlled both by the sites and the type of substrata. Pioneer microalgal communities were dominated by the same two diatom species, viz. Licmophora gracilis and Cylindrotheca closterium, at both sites, irrespective of the substrata involved. However, the density of diatoms followed the same trend at both sites with a significant effect of all the AF coatings compared to Teflon and polystyrene.  相似文献   
995.
Phototrophic biofilms are used in a variety of biotechnological and industrial processes. Understanding their structure, ie microbial composition, is a necessary step for understanding their function and, ultimately, for the success of their application. DNA analysis methods can be used to obtain information on the taxonomic composition and relative abundance of the biofilm members. The potential bias introduced by DNA extraction methods in the study of the diversity of a complex phototrophic sulfide-oxidizing biofilm was examined. The efficiency of eight different DNA extraction methods combining physical, mechanical and chemical procedures was assessed. Methods were compared in terms of extraction efficiency, measured by DNA quantification, and detectable diversity (16S rRNA genes recovered), evaluated by denaturing gradient gel electrophoresis (DGGE). Significant differences were found in DNA yields ranging from 116 ± 12 to 1893 ± 96 ng of DNA. The different DGGE fingerprints ranged from 7 to 12 bands. Methods including phenol–chloroform extraction after enzymatic lysis resulted in the greatest DNA yields and detectable diversity. Additionally, two methods showing similar yields and retrieved diversity were compared by cloning and sequencing. Clones belonging to members of the Alpha-, Beta- and Gamma- proteobacteria, Bacteroidetes, Cyanobacteria and to the Firmicutes were recovered from both libraries. However, when bead-beating was applied, clones belonging to the Deltaproteobacteria were also recovered, as well as plastid signatures. Phenol–chloroform extraction after bead-beating and enzymatic lysis was therefore considered to be the most suitable method for DNA extraction from such highly diverse phototrophic biofilms.  相似文献   
996.
This article describes the works of two 19th-century chronobiologists. Thomas Laycock (1812-1876), who held the Chair of Medicine in Edinburgh from 1855-1876, published a series of seven articles in Lancet, all dedicated to periodicities in “vital phenomena.” Laycock considered the understanding of periodicities essential for the advancement of the treatment of diseases. Edward Smith (1818-1874) was a pioneer in experimental chronobiology. In his 1861 book entitled: Health and disease as influenced by daily, seasonal and other cyclical changes in the human, Smith summarized a large number of experiments in which he investigated the occurrence of periodicities in pulse rate, urine flow, urea excretion, and respiration. From his experimental results and those of others, Smith drew practical conclusions regarding patients' care, the timing of drug administration, and the design of night work.  相似文献   
997.
《Ostrich》2013,84(1):83-88
The paper ‘Bird diversity in the savanna habitats of Akagera National Park, Rwanda, in the post-war recovery period’ by Gatali and Wallin (Ostrich 86(3): 267–276, 2015) makes several claims for new species records for Akagera National Park and Rwanda. We found that Gatali and Wallin recorded several species considered very rare in Rwanda and new discoveries; these findings often contradicted the existing literature. We doubt the validity of 34 species records and we aim to demonstrate that these claims are mostly the result of misidentification or human error and consider that future researchers should use their findings with caution. Some findings around more common species may be validated through further studies and we encourage others to conduct fieldwork in Akagera National Park.  相似文献   
998.
Eucommia ulmoides, a traditional Chinese medicinal plant, is endangered as a consequence of long‐term and widespread harvest in the late 20th century. It has been widely cultivated as a source of herbal medicine and for use in the organic chemical industry in China. In this study, eight microsatellite markers were applied to investigate genetic diversity in E. ulmoides. Three hundred individuals from one semi‐wild population and nine cultivated populations across its main production area were collected. A high level of genetic diversity at population levels (HE = 0.716) was observed. The highly outcrossed mating system, high longevity of E. ulmoides and seed admixture may be responsible for high genetic variation within populations. A genetic bottleneck was observed in one population. Populations were only slightly differentiated from one another (FST = 0.063); this was also supported by AMOVA, which revealed that 94.05% of the total variation resided within populations. This is probably attributable to long‐distance gene flow mediated by the exchange of seeds by local farmers. Implications of these results for the conservation of genetic resources of E. ulmoides are discussed. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 775–785.  相似文献   
999.
Islands offer an interesting framework in which to study the effect of geographical isolation on population genetic differentiation. For plant species with high dispersal abilities, however, oceanic barriers may not represent a factor promoting strong population structure. In this work, we analysed seven nuclear microsatellite loci in Ilex (Aquifoliaceae), a bird‐dispersed plant group, to infer patterns of genetic differentiation among Macaronesian taxa: I. canariensis, I. perado ssp. lopezlilloi, I. perado ssp. platyphylla (Canary Islands) and I. perado ssp. azorica (Azores). In agreement with current taxonomic classification, our results revealed a high genetic differentiation between Ilex lineages (I. canariensis and the I. perado complex), and also supported previous hypotheses that these are the result of independent dispersal events to the islands. In contrast, genetic differentiation between I. perado ssp. azorica and the two subspecies from the Canaries was high, suggesting that taxonomic revision may be necessary. Levels of genetic variation at microsatellite loci in ssp. azorica were, in addition, the lowest reported among Macaronesian bird‐dispersed taxa. Lastly, low genetic differentiation was observed between subspecies occurring on the same island (sspp. platyphylla and lopezlilloi). In summary, our results revealed contrasting patterns between Macaronesian Ilex lineages: I. canariensis displayed moderate population structure across islands, whereas the I. perado complex showed strong differentiation among populations sampled on different islands. Thus, the Macaronesian Ilex taxa show that long‐distance dispersal syndromes (ornithochory) do not always ensure genetic connectivity across large areas in island systems. Plant groups that successfully colonized the islands on multiple occasions may have found barriers to gene flow within certain lineages. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 258–268.  相似文献   
1000.
Abstract

Recently in numerous European countries of immigration, there has been a widespread ‘moral panic’ about immigrants and ethnic diversity. In The Netherlands, a backlash has occurred in policy and in public discourse, with migrants being blamed for not meeting their responsibility to integrate and for practising ‘backward religions’. Why is it that a self-defined ‘liberal’ and ‘tolerant’ society demands conformity, compulsion and introduces seemingly undemocratic sanctions towards immigrants in a move towards assimilationism? These issues are analysed by providing an overview of modes of incorporation of immigrants in the Netherlands and it presents evidence on the socio-economic situation of immigrants. The article argues that patterns of disadvantage cannot be explained solely by the low human capital attributes of the original immigrants. In spite of multiculturalism, the causes have to be sought in pervasive institutional discrimination and the persistence of a culture of racism. The study argues that a shift to assimilation is more likely to create further societal divisions.  相似文献   
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