Reproductive and productive performances of Santa Inês ewes submitted to breeding in different periods of the Amazonian humid tropical climate     

Felipe Nogueira Soares  Maria Emilia Franco Oliveira  Luciana Cristina Padilha-Nakaghi  Luís Guilherme de Oliveira  Marcus Antônio Rossi Feliciano  Felipe Brener Bezerra de Oliveira  Pedro Paulo Maia Teixeira  Wilter Ricardo Russiano Vicente  Cristian Faturi  Luiz Fernando de Souza Rodrigues 《Tropical animal health and production》2015,47(8):1465-1471

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Adoption of milk cooling technology among smallholder dairy farmers in Kenya     

Florence Gathoni Gachango  Laura Mørch Andersen  Søren Marcus Pedersen 《Tropical animal health and production》2014,46(1):179-184

Factors influencing adoption of milk cooling technology were studied with data for 90 smallholder dairy farmers who were randomly selected from seven dairy cooperative societies in Kiambu County, Kenya. Logistic regression identified the age of the household head, daily household milk consumption, freehold land ownership, fodder production area, number of female calves, cooperative membership and cooperative services as significant factors influencing farmers’ willingness to invest in milk cooling technology. These findings offer an entry point for increased interventions by policy makers and various dairy sector stakeholders in promoting milk cooling technology with the aim of significantly reducing post-harvest losses and increasing the sector’s competitiveness.  相似文献   

Factors (type,colour, density,and shape) determining the removal of marine plastic debris by seabirds from the South Pacific Ocean: Is there a pattern?     

Valeria Hidalgo-Ruz  Guillermo Luna-Jorquera  Marcus Eriksen  Hanna Frick  Diego Miranda-Urbina  Matias Portflitt-Toro  Marcelo M. Rivadeneira  Christopher J.R. Robertson  R. Paul Scofield  Juan Serratosa  Cristián G. Suazo  Martin Thiel 《水产资源保护:海洋与淡水生态系统》2021,31(2):389-407

1. While floating near the sea surface plastic debris interacts with a number of external factors, including many different organisms. Seabirds have the most extensive documented history of interactions with plastics, through ingestion, entanglement, and nest construction.
2. In the present study, eight seabird species from the South Pacific Ocean were used as a proxy to determine potential patterns of removal of marine plastic debris, and three hypotheses were tested in relation to their feeding habits and nesting areas.
3. Plastics from abiotic compartments (Chilean continental coast, South Pacific Gyre, and Rapa Nui beaches) and biotic compartments (surface-feeding seabirds, diving seabirds, and nesting areas) were compared, according to their type, colour, shape, and density.
4. Continental beaches had a relatively wide range of colours and shapes, with many non-buoyant plastics. Samples from the South Pacific Gyre (SPG) and Rapa Nui (Easter Island) beaches comprised mainly hard, rounded, buoyant, and white/grey plastics.
5. These results indicate that the composition of floating plastics from terrestrial sources changes during transport with oceanic currents, reducing the proportion of prey-like plastics present in the subtropical gyres.
6. The stomach contents of surface-feeding and diving seabirds were dominated by hard, white/grey, and round plastic items, similar to plastics from the SPG, suggesting non-selective (accidental or secondary) ingestion.
7. Nesting areas had a more variable composition of brightly coloured plastics, suggesting a pattern of selective removal of plastics by seabirds, probably from oceanic sources.
8. The present study reveals extensive interactions of seabirds with plastics on a broader scale, which is highly relevant given that the impacts of plastics on seabirds are increasing worldwide, compromising their efficient conservation.

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Novel ecosystems and social-ecological resilience     

Marcus J. Collier 《Landscape Ecology》2015,30(8):1363-1369

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Zeitliche Entwicklung und aktuelle Beurteilung der Bodenkontamination durch Blei im Umfeld eines glasverarbeitenden Werkes in Thüringen     

Jürgen Einax  Marcus Krieg 《植物养料与土壤学杂志》1995,158(4):355-359

Temporal development and actual assessment of a lead soil contamination in the surroundings of a glass factory in Thuringia In this study the lead content in the area around a source of emission was investigated. The lead pollution of the soil originates in lead containing dust from glass production. The overall contamination of the considered area was found out using the geostatistical method of kriging. The measurement included 34 samples taken at different spots around the source of emission. A similar study as this was made in the beginning of the eighties. In comparison to the latter the recent results show lower values of lead contamination of the soil, but at the same time the area of pollution enlarges. At a high polluted point a profile of the soil was investigated. It showed that the lead content decreases rapidly with increasing depth. A contamination by lead can be detected down to a depth of 20 cm. The lead values show a significant correlation with the carbon contents of the soil. An estimation of the amount of lead stored in the investigated area indicates an obvious reduction from 2.1 t in 1985 to 1 t in 1994. This can be explained by a secondary transfer of the dust from the considered to adjoining areas.  相似文献   

Paleontology. Sauropod gigantism     

Sander PM  Clauss M 《Science (New York, N.Y.)》2008,322(5899):200-201

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Parallel patterns of evolution in the genomes and transcriptomes of humans and chimpanzees     

Khaitovich P  Hellmann I  Enard W  Nowick K  Leinweber M  Franz H  Weiss G  Lachmann M  Pääbo S 《Science (New York, N.Y.)》2005,309(5742):1850-1854

The determination of the chimpanzee genome sequence provides a means to study both structural and functional aspects of the evolution of the human genome. Here we compare humans and chimpanzees with respect to differences in expression levels and protein-coding sequences for genes active in brain, heart, liver, kidney, and testis. We find that the patterns of differences in gene expression and gene sequences are markedly similar. In particular, there is a gradation of selective constraints among the tissues so that the brain shows the least differences between the species whereas liver shows the most. Furthermore, expression levels as well as amino acid sequences of genes active in more tissues have diverged less between the species than have genes active in fewer tissues. In general, these patterns are consistent with a model of neutral evolution with negative selection. However, for X-chromosomal genes expressed in testis, patterns suggestive of positive selection on sequence changes as well as expression changes are seen. Furthermore, although genes expressed in the brain have changed less than have genes expressed in other tissues, in agreement with previous work we find that genes active in brain have accumulated more changes on the human than on the chimpanzee lineage.  相似文献   

A SNP map of the rat genome generated from cDNA sequences   总被引：1，自引：0，他引：1  

Zimdahl H  Nyakatura G  Brandt P  Schulz H  Hummel O  Fartmann B  Brett D  Droege M  Monti J  Lee YA  Sun Y  Zhao S  Winter EE  Ponting CP  Chen Y  Kasprzyk A  Birney E  Ganten D  Hubner N 《Science (New York, N.Y.)》2004,303(5659):807

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Ephedra-free is not danger-free     

Marcus DM  Grollman AP 《Science (New York, N.Y.)》2003,301(5640):1669-71; author reply 1669-71

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Double-stranded ribonuclease coinduced with interferon   总被引：5，自引：0，他引：5  

J M Meegan  P I Marcus 《Science (New York, N.Y.)》1989,244(4908):1089-1091

Double-stranded (ds) RNA and many viruses are inducers of interferon (IFN), the latter presumably because they contain, or can form, dsRNA. Concomitant with the induction of IFN in chicken embryo cells was the induction of a novel double-stranded ribonuclease (dsRNase), which was released into the medium and continued to accumulate long after IFN production ceased. Only avian cells (chicken, quail, turkey, or duck) expressed high levels of this dsRNase; mammalian, turtle, or fish cells did not. Production of the nuclease was inducer dose-dependent. Optimum pH and cation requirements distinguished it from other dsRNase activities. Degradation of dsRNA was endonucleolytic. Activity resided in a molecule of an Mr of approximately 34,500. Low levels of a single-stranded (ss) RNase activity were inseparable from the dsRNase. The role for a dsRNA-inducible dsRNase released from cells is unknown.  相似文献