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41.
Geoffrey?JonesEmail author Rachel?J.?Keedwell Alasdair?D.?L.?Noble Duncan?I.?Hedderley 《Journal of Agricultural, Biological & Environmental Statistics》2005,10(3):306-320
The motivation for this work was to investigate the possibility of accurately determining the age of a tern chick using easily
obtained body measurements. We describe the construction of a nonlinear multivariate hierarchical model for chick growth and
show how it can be estimated using Markov chain Monte Carlo techniques. A simple extension of the analysis allows for estimation
of the ages of unknown chicks. Posterior distributions of the unknown ages are derived, so that the accuracy of age determination
can be examined. We further extend our model and analysis to include the possibility that chicks fall into distinct groups
with different growth characteristics. The technique is illustrated using data on the weight and wing length of black-fronted
terns from the Ohau River, New Zealand. It is found that dating to within one day is possible, but only in some areas of the
data space. The concept of “braiding” of multivariate growth curves is introduced to explain the varying accuracy of age determination. 相似文献
42.
Predator control for protecting kaki (Himantopus novaezelandiae)—lessons from 20 years of management
In New Zealand, the endemic kaki or black stilt (Himantopus novaezelandiae) has been the focus of intensive conservation management for the past 20 years. Threatened by predation and habitat loss, the population fell to as low as 23 birds before management was implemented to reverse the decline. Predator trapping has been one form of management intervention in the wild, yet despite 20 years of control, there is only limited evidence to suggest that predator trapping is beneficial for the survival of kaki. Lack of adequate experimental design and understanding of the predator-prey dynamics in the system in which kaki live appear to be the main reasons why the benefits of predator control are not consistently clear. An adaptive management approach would have provided more information on the efficacy of predator trapping and increased understanding of the inter-relationships between kaki survival and predator abundance. 相似文献
43.
44.
Mitton-Fry RM Anderson EM Hughes TR Lundblad V Wuttke DS 《Science (New York, N.Y.)》2002,296(5565):145-147
The essential Cdc13 protein in the yeast Saccharomyces cerevisiae is a single-stranded telomeric DNA binding protein required for chromosome end protection and telomere replication. Here we report the solution structure of the Cdc13 DNA binding domain in complex with telomeric DNA. The structure reveals the use of a single OB (oligonucleotide/oligosaccharide binding) fold augmented by an unusually large loop for DNA recognition. This OB fold is structurally similar to OB folds found in the ciliated protozoan telomere end-binding protein, although no sequence similarity is apparent between them. The common usage of an OB fold for telomeric DNA interaction demonstrates conservation of end-protection mechanisms among eukaryotes. 相似文献
45.
Pulsing electromagnetic fields of low frequency and strength have been inductively coupled across skin, directly to bone, to enhance the repair of canine osteotomies. The induced voltage field in bone appears to increase the organization and strength of the repair process at 28 days after "fracture." 相似文献
46.
The construction of multicellular organisms depends on stem cells-cells that can both regenerate and produce daughter cells that undergo differentiation. Here, we show that the gaseous messenger ethylene modulates cell division in the cells of the quiescent center, which act as a source of stem cells in the seedling root. The cells formed through these ethylene-induced divisions express quiescent center-specific genes and can repress differentiation of surrounding initial cells, showing that quiescence is not required for these cells to signal to adjacent stem cells. We propose that ethylene is part of a signaling pathway that modulates cell division in the quiescent center in the stem cell niche during the postembryonic development of the root system. 相似文献
47.
The US food retailing industry continues to concentrate and consolidate. Power in the agriculture, food, and nutrition system
has shifted from producers to processors, and is now shifting to retailers. Currently, only eight food-retailing corporations
control the majority of food sales in the United States. Expanding on previous research by Lyson and Raymer (2000, Agriculture and Human Values 17: 199–208), this paper examines the characteristics of the boards of directors of the leading food retailing corporations
and the indirect interlocks that bind the food retailers into a corporate community.
Rachel
Schwartz
is a PhD Candidate in the Department of Development Sociology at Cornell University. Her research interests are focused on
the relationship between food retailers and food consumers in the United States, especially in regards to the construction
of the concept of “choice.”
Thomas Lyson
was Liberty Hyde Bailey Professor in the Department of Development Sociology at Cornell University. His interests included
the relationship of agriculture and food systems on community economic development and population health. His most recent
book, Civic Agriculture, developed a problem-solving model for food and agriculture issues. Dr. Lyson passed away in December
2006. 相似文献
48.
Morrow EM Yoo SY Flavell SW Kim TK Lin Y Hill RS Mukaddes NM Balkhy S Gascon G Hashmi A Al-Saad S Ware J Joseph RM Greenblatt R Gleason D Ertelt JA Apse KA Bodell A Partlow JN Barry B Yao H Markianos K Ferland RJ Greenberg ME Walsh CA 《Science (New York, N.Y.)》2008,321(5886):218-223
To find inherited causes of autism-spectrum disorders, we studied families in which parents share ancestors, enhancing the role of inherited factors. We mapped several loci, some containing large, inherited, homozygous deletions that are likely mutations. The largest deletions implicated genes, including PCDH10 (protocadherin 10) and DIA1 (deleted in autism1, or c3orf58), whose level of expression changes in response to neuronal activity, a marker of genes involved in synaptic changes that underlie learning. A subset of genes, including NHE9 (Na+/H+ exchanger 9), showed additional potential mutations in patients with unrelated parents. Our findings highlight the utility of "homozygosity mapping" in heterogeneous disorders like autism but also suggest that defective regulation of gene expression after neural activity may be a mechanism common to seemingly diverse autism mutations. 相似文献
49.
50.
Atlas R Campbell P Cozzarelli NR Curfman G Enquist L Fink G Flanagin A Fletcher J George E Hammes G Heyman D Inglesby T Kaplan S Kennedy D Krug J Levinson R Marcus E Metzger H Morse SS O'Brien A Onderdonk A Poste G Renault B Rich R Rosengard A Salzburg S Scanlan M Shenk T Tabor H Varmus H Wimmer E Yamamoto K;Journal Editors Authors Group 《Science (New York, N.Y.)》2003,299(5610):1149