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1.
Summary The use of reticulated polyurethane foam as a support material for the immobilization of methanogenic associations and its application to the anaerobic treatment of fine particulate solid wastes was investigated. The colonization of polyurethane support particles in a continuous upflow reactor fed on a mixture of acetate, propionate and butyrate, was both rapid and dense. The combination of rumen microorganisms and colonized support particles in a two-phase digester resulted in an efficient anaerobic decomposition of papermill sludge. 相似文献
2.
A three-dimensional musculoskeletal model for gait analysis. Anatomical variability estimates 总被引:2,自引:0,他引:2
Three-dimensional coordinates defining the origin and insertion of 40 muscle units, and bony landmarks for osteometric scaling were identified on dry bone specimens. Interspecimen coordinate differences along the anterior-posterior axis of the pelvis and the long bone axes of the pelvis, femur and leg were reduced by scaling but landmark differences along the other axes were not. The coordinates were mapped to living subjects using close-range photogrammetry to locate superficial reference markers. The error of predicting the positions of internal coordinates was assessed by comparing joint centre locations calculated from local axes defining the orientation of segments superior and inferior to a joint. A difference was attributed to: anatomical variability not accounted for by scaling; errors in identifying and placing reference landmarks; the accuracy of locating markers using photogrammetry and error introduced by marker oscillation during movement. Anatomical differences between specimens are one source of error in defining a musculoskeletal model but larger errors are introduced when such models are mapped to living subjects. 相似文献
3.
Background
Long-term benefits in animal breeding programs require that increases in genetic merit be balanced with the need to maintain diversity (lost due to inbreeding). This can be achieved by using optimal contribution selection. The availability of high-density DNA marker information enables the incorporation of genomic data into optimal contribution selection but this raises the question about how this information affects the balance between genetic merit and diversity.Methods
The effect of using genomic information in optimal contribution selection was examined based on simulated and real data on dairy bulls. We compared the genetic merit of selected animals at various levels of co-ancestry restrictions when using estimated breeding values based on parent average, genomic or progeny test information. Furthermore, we estimated the proportion of variation in estimated breeding values that is due to within-family differences.Results
Optimal selection on genomic estimated breeding values increased genetic gain. Genetic merit was further increased using genomic rather than pedigree-based measures of co-ancestry under an inbreeding restriction policy. Using genomic instead of pedigree relationships to restrict inbreeding had a significant effect only when the population consisted of many large full-sib families; with a half-sib family structure, no difference was observed. In real data from dairy bulls, optimal contribution selection based on genomic estimated breeding values allowed for additional improvements in genetic merit at low to moderate inbreeding levels. Genomic estimated breeding values were more accurate and showed more within-family variation than parent average breeding values; for genomic estimated breeding values, 30 to 40% of the variation was due to within-family differences. Finally, there was no difference between constraining inbreeding via pedigree or genomic relationships in the real data.Conclusions
The use of genomic estimated breeding values increased genetic gain in optimal contribution selection. Genomic estimated breeding values were more accurate and showed more within-family variation, which led to higher genetic gains for the same restriction on inbreeding. Using genomic relationships to restrict inbreeding provided no additional gain, except in the case of very large full-sib families. 相似文献4.
5.
The eyes of Macrosoma sp. (Lepidoptera: Hedyloidea): a nocturnal butterfly with superposition optics
The visual system of nocturnal Hedyloidea butterflies was investigated for the first time, using light and electron microscopy. This study was undertaken to determine whether hedylids possess the classic superposition eye design characteristic of most moths, or apposition eyes of true butterflies (Papilionoidea), and, to gain insights into the sensory ecology of the Hedyloidea. We show that Macrosoma heliconiaria possesses a superposition-type visual mechanism, characterized by long cylindrical crystalline cones, a lack of corneal processes, 8 constricted retinular sense cells, rhabdoms separated from the crystalline cones forming a translucent 'clear zone', and tight networks of trachea that form a tapetum proximal to the retina and which also surround the rhabdoms to form a tracheal sheath. Dark-adapted individuals of M. heliconiaria, M. conifera, and M. rubidinarea exhibited distal retinular pigment migration, forming an eye glow. Correspondingly, light-exposure induced pigment to migrate proximally, causing the eye glow to be replaced by a dark pseudopupil. Other characteristics of the visual system, including relative eye size, facet size, and external morphology of the optic lobes, are mostly 'moth like' and correlate with an active, nocturnal lifestyle. The results are discussed in relation to the evolution of lepidopteran eyes, and the sensory ecology of this poorly understood butterfly superfamily. 相似文献
6.
Background
Gene loss, inversions, translocations, and other chromosomal rearrangements vary among species, resulting in different rates of structural genome evolution. Major chromosomal rearrangements are rare in most eukaryotes, giving large regions with the same genes in the same order and orientation across species. These regions of macrosynteny have been very useful for locating homologous genes in different species and to guide the assembly of genome sequences. Previous analyses in the fungi have indicated that macrosynteny is rare; instead, comparisons across species show no synteny or only microsyntenic regions encompassing usually five or fewer genes. To test the hypothesis that chromosomal evolution is different in the fungi compared to other eukaryotes, synteny was compared between species of the major fungal taxa. 相似文献7.
Background
In the analysis of complex traits, genetic effects can be confounded with non-genetic effects, especially when using full-sib families. Dominance and epistatic effects are typically confounded with additive genetic and non-genetic effects. This confounding may cause the estimated genetic variance components to be inaccurate and biased.Methods
In this study, we constructed genetic covariance structures from whole-genome marker data, and thus used realized relationship matrices to estimate variance components in a heterogenous population of ~ 2200 mice for which four complex traits were investigated. These mice were genotyped for more than 10,000 single nucleotide polymorphisms (SNP) and the variances due to family, cage and genetic effects were estimated by models based on pedigree information only, aggregate SNP information, and model selection for specific SNP effects.Results and conclusions
We show that the use of genome-wide SNP information can disentangle confounding factors to estimate genetic variances by separating genetic and non-genetic effects. The estimated variance components using realized relationship were more accurate and less biased, compared to those based on pedigree information only. Models that allow the selection of individual SNP in addition to fitting a relationship matrix are more efficient for traits with a significant dominance variance. 相似文献8.
Veronica L. Bura Antoine K. Hnain Justin N. Hick Jayne E. Yack 《Journal of Insect Behavior》2012,25(2):114-126
The tobacco hornworm (Manduca sexta) is a model organism extensively studied for many aspects of its biology, including its anti-predator strategies. We report
on a novel component of this caterpillar’s defence repertoire: sound production. Late instar caterpillars produce discrete
clicking sounds in response to disturbance. Click trains range in duration from 0.3–20.0 s (mean 3.3 ± 4.8 s) and contain
2–41 clicks (mean 7.1 ± 9.5). Sounds are broadband with a dominant frequency of 29.8 ± 4.9 kHz. We investigated the mechanism
of sound production by selectively ablating three identified sets of ridges on the mandibles, and determined that ridges on
the inner face strike the outer and incisor ridges on the opposing mandible to produce multi-component clicks. We tested the
hypothesis that clicks function in defence using simulated attacks with blunt forceps. In single attack trials 77% of larvae
produced sound and this increased to 100% in sequential attacks. Clicks preceded or accompanied regurgitation in 93% of multiple
attack trials, indicating that sound production may function in acoustic aposematism. Sound production is also accompanied
by other behaviours including directed thrashing, head curling, and biting, suggesting that sounds may also function as a
general warning of unprofitability. 相似文献
9.
The present study analyzed the drosophilid assemblages in different levels of urbanization in the city of Porto Alegre, Rio Grande do Sul, Brazil. Collections were carried out in 2008 in three different environments: a highly urbanized area????Jardim Botanico,?? a forested area with intermediary urbanization????Parque Gabriel Knijnik,?? and in a relatively well-preserved forested area, although threatened by the urban growth????Morro Santana.?? In Jardim Botanico, 36 species belonging to four genera were found, with high abundance of exotic species as Drosophila simulans Sturtevant and Zaprionus indianus (Gupta). In Parque Gabriel Knijnik, 33 species that belonged to four genera were found, with higher abundances of native species belonging to the Drosophila tripunctata species group and Drosophila willistoni species subgroup, and lower abundance of exotic species. As for Morro Santana, 32 species and three genera were found, with higher abundances of native groups, low representativeness of exotic species, and absence of Zaprionus indianus. The analysis of the Jaccard index showed higher similarity in the species composition between samples collected in summer and autumn, and between samples collected in winter and spring. On the other hand, the Morisita index differentiated Jardim Botanico from the other two studied sites. Our results show that Morro Santana is an important area of native biodiversity, reinforcing, therefore, the inclusion of this area in the project for the creation of an ecological corridor as proposed by the Ministry of the Environment of Brazil. 相似文献
10.
Nadine?AME?van der BeekEmail author Juna?M?de Vries Marloes?LC?Hagemans Wim?CJ?Hop Marian?A?Kroos John?HJ?Wokke Marianne?de Visser Baziel?GM?van Engelen Jan?BM?Kuks Anneke?J?van der Kooi Nicolette?C?Notermans Karin?G?Faber Jan?JGM?Verschuuren Arnold?JJ?Reuser Ans?T?van der Ploeg Pieter?A?van Doorn 《Orphanet journal of rare diseases》2012,7(1):88