Analysis of Multiple Binary Responses Using a Threshold Model     

Ling-Yun Chang  Sajjad Toghiani  Ashley Ling  El H. Hay  Sammy E. Aggrey  Romdhane Rekaya 《Journal of Agricultural, Biological & Environmental Statistics》2017,22(4):640-651

Several discrete responses, such as health status, reproduction performance and meat quality, are routinely collected for several livestock species. These traits are often of binary or discrete nature. Genetic evaluation for these traits is frequently conducted using a single-trait threshold model, or they are considered continuous responses either in univariate or in multivariate context. Implementation of threshold models in the presence of several binary responses or a mixture of binary and continuous responses is far from simple. The complexity of such implementation is primarily due to the incomplete randomness of the residual (co)variance matrix. In the current study, a multiple binary trait simulation was carried out in order to implement and validate a new procedure for dealing with the consequences of the restrictions imposed to the residual variance using threshold models. Using three and eight binary responses, the proposed method was able to estimate all unknown parameters without any noticeable bias. In fact, for simulated residual correlations ranging from ?0.8 to 0.8, the resulting HPD 95% intervals included the true values in all cases. The proposed procedure involved limited additional computational cost and is straightforward to implement independent of the number of binary responses involved in the analysis. Monitoring of the convergence of the procedure must be conducted at the identifiable scale, and special care must be placed on the selection of the prior of the non-identifiable model. The latter could have serious consequences on the final results due to potential truncation of the parameter space.  相似文献   

Activation of the ovine hypothalamic-pituitary-adrenal axis and febrile response by interleukin-6: A comparative study with bacterial lipopolysaccharide endotoxin     

Niel A. Karrow  Qiumei You  Carl McNicoll  Jack Hay 《Canadian journal of veterinary research》2010,74(1):30-33

Sheep were subjected to immune challenge with either recombinant human interleukin-6 (rhIL-6; 2.0 μg/kg; n = 5), Escherichia coli lipopolysaccharide (LPS) endotoxin (400 ng/kg; n = 7), or saline (n = 6) to determine if IL-6 activates the febrile and hypothalamic-pituitary-adrenal axis (HPAA) responses in sheep, and to compare these responses with those associated with endotoxemia. Blood was collected over time to measure plasma adrenocorticotropic hormone (ACTH) and serum cortisol concentrations as indicators of HPAA activity. Unlike LPS, rhIL-6 was not pyrogenic in sheep at this challenge dose. In contrast, rhIL-6 elicited ACTH and cortisol responses that peaked earlier than those induced by LPS. These results suggest that this dose of IL-6, alone, is not sufficient to elicit the febrile response in sheep, however, it is a potent activator of the ovine HPAA response.  相似文献   

A new anthracnose disease of pyrethrum caused by Colletotrichum tanaceti sp. nov     

M. Barimani  S. J. Pethybridge  N. Vaghefi  F. S. Hay  P. W. J. Taylor 《Plant pathology》2013,62(6):1248-1257

A new pathogen of pyrethrum (Tanacetum cinerariifolium) causing anthracnose was described as Colletotrichum tanaceti based on morphological characteristics and a four‐gene phylogeny consisting of rDNA‐ITS, β‐tubulin (TUB2), glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) and actin (ACT) gene sequences. The fungus produced perithecia in culture, requiring an opposite mating type isolate in a heterothallic manner. The initial infection strategy on pyrethrum leaves involved the formation of appressoria followed by production of multilobed infection vesicles in the epidermal cells. Infection and colonization then proceeded through thinner secondary hyphae, which resulted in the initial production of water‐soaked lesions followed by black necrotic lesions. The infection process was suggestive of a hemibiotrophic infection strategy. Moreover, phylogenetic analysis clearly showed that C. destructivum, C. higginsianum and C. panacicola were separate species that also had similar intracellular hemibiotrophic infection strategies as C. tanaceti, which all clustered in the C. destructivum complex. Colletotrichum spp. were detected at 1% incidence in seed of 1 of 19 seed lines, indicating the potential for seed as a source of inoculum into crops. Colletotrichum tanaceti was detected in leaf lesions from 11 of 24 pyrethrum fields surveyed between April and July 2012, at a frequency of 1·3–25·0% of lesions. Anthracnose probably contributes to the complex of foliar diseases reducing green leaf area in pyrethrum fields in Australia.  相似文献   

The growth and volatile oil yield of summer savory (iSatureja hortensis) in a cool wet environment     

K. P. Svoboda  R. K. M. Hay  P. G. Waterman 《The Journal of Horticultural Science and Biotechnology》2013,88(6):659-665

Stands of the annual culinary herb summer savory (Satureja hortensis L) were grown over four contrasting seasons, 1984-87, at Auchincruive in southwest Scotland. All crops matured in mid- to late August, yielding volatile oils of high quality. Total dry-matter yields per hectare were similar to those reported from eastern Europe, but oil yields were lower because of the genotype used, and there was considerable variation in dry-matter and oil yields between seasons. Variation in crop management (planting date, fertilization) affected oil yield only through changes in crop dry-matter production. Methods of increasing dry-matter and oil yields, and the potential of summer savory as an alternative crop for cool wet regions, are discussed.  相似文献   

Intra-articular anaesthesia of the equine stifle improves foot lameness     

A. Radtke  L. A. Fortier  S. Regan  S. Kraus  M. L. Delco 《Equine veterinary journal》2020,52(2):314-319

  相似文献   

The Effect of Natural Mulches on Crop Performance, Weed Suppression and Biochemical Constituents of Catnip and St. John's Wort     

Duppong LM  Delate K  Liebman M  Horton R  Romero F  Kraus G  Petrich J  Chowdbury PK 《Crop science》2004,44(3):861-869

Because of expanding markets for high-value niche crops, opportunities have increased for the production of medicinal herbs in the USA. An experiment was conducted in 2001 and 2002 near Gilbert, IA, to study crop performance, weed suppression, and environmental conditions associated with the use of several organic mulches in the production of two herbs, catnip (Nepeta cataria L.) and St. John's wort (Hypericum perforatum L. 'Helos'). Treatments were arranged in a completely randomized design and included a positive (hand-weeded) control, a negative (nonweeded) control, oat straw, a flax straw mat, and a nonwoven wool mat. Catnip plant height was significantly greater in the oat straw than the other treatments at 4 wk through 6 wk in 2001; at 4 to 8 wk in 2002, catnip plant height and width was significantly lower in the negative control compared with the other treatments. Catnip yield was significantly higher in the flax straw mat than all other treatments in 2001. In 2002, St. John's wort yields were not statistically different in any treatments. All weed management treatments had significantly fewer weeds than the non-weeded rows in 2002. Total weed density comparisons in each crop from 2 yr showed fewer weeds present in the flax straw and wool mat treatments compared with positive control plots. There was no significant weed management treatment effect on the concentration of the target compounds, nepetalactone in catnip and pseudohypericin-hypericin in St. John's wort, although there was a trend toward higher concentrations in the flax straw treatment.  相似文献   

Shoshoni: A new potato,combining high yielding ability and resistance to scab and verticillium wilt     

J. E. Kraus  F. P. Cullinan 《American Journal of Potato Research》1963,40(4):142-142

  相似文献   

The impact of thematic resolution on the patch-mosaic model of natural landscapes   总被引：1，自引：1，他引：0  

Guillermo Castilla  Kerry Larkin  Julia Linke  Geoffrey J. Hay 《Landscape Ecology》2009,24(1):15-23

We argue that thematic resolution, i.e., the level of categorical detail of a thematic map expressed by the number of classes included in the map legend, is an inherent component of the scale at which a landscape is analyzed. Changing the number of classes can change the configuration of the patch mosaic as much as changing the grain does. We address recent calls in this and other journals to deepen research in this topic. In particular, we report how thematic resolution affects the patchiness of mosaics representing natural landscapes, which have seldom been studied in this respect. We selected seven 50 × 50 km landscapes within national parks, each representative of a world biome. We applied an object-based unsupervised classification to Landsat TM imagery of these landscapes using increasing numbers of classes, between 2 and 50, and derived curves of mean patch size and patch density for each site. Our results are consistent with previous findings in that the patchiness of output mosaics increases monotonically with increasing thematic resolution, with a higher rate of increase up to eight classes that declines until it becomes roughly constant for more than 16 classes. However, this constant rate of increase is still considerable, meaning that, at least for natural landscapes, there is no threshold beyond which the patch-mosaic model is independent of the conceptual filter applied. This dependence on human fiat calls for re-thinking the patch-mosaic paradigm.  相似文献   

The effect of 2,4-d treatment on free amino acids in potato tubers     

Merle G. Payne  Jess L. Fults  Ruth J. Hay 《American Journal of Potato Research》1952,29(6):142-150

  相似文献   

Amitotic neuroblastoma cells used for neural implants in monkeys   总被引：1，自引：0，他引：1  

D M Gash  M F Notter  S H Okawara  A L Kraus  R J Joynt 《Science (New York, N.Y.)》1986,233(4771):1420-1422

The potential utility of cultured neuroblastoma cells as donor tissue for neutral implants into the mammalian brain has been examined. Cells from a human neuroblastoma cell line, IMR-32, were labeled with [3H]thymidine and chemically rendered amitotic. These differentiated IMR-32 cells were grafted into the hippocampi of five adult African Green monkeys, and graft survival was evaluated for up to 270 days after transplantation. Autoradiographically labeled grafted cells were identified in four animals. Processes from grafted cells could be followed for distances of up to 150 micrometers into the host brain. No evidence for neoplastic growth of the transplant was found. Thus, grafted neuroblastoma cells can survive for prolonged periods in the primate brain and may serve as a practical source of donor tissue for neural implants.  相似文献