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BackgroundBovine respiratory disease complex (BRDC) is an infectious disease of cattle that is caused by a combination of viral and/or bacterial pathogens. Selection for cattle with reduced susceptibility to respiratory disease would provide a permanent tool for reducing the prevalence of BRDC. The objective of this study was to identify BRDC susceptibility loci in pre-weaned Holstein calves as a prerequisite to using genetic improvement as a tool for decreasing the prevalence of BRDC. High density SNP genotyping with the Illumina BovineHD BeadChip was conducted on 1257 male and 757 female Holstein calves from California (CA), and 767 calves identified as female from New Mexico (NM). Of these, 1382 were classified as BRDC cases, and 1396 were classified as controls, with all phenotypes assigned using the McGuirk health scoring system. During the acquisition of blood for DNA isolation, two deep pharyngeal and one mid-nasal diagnostic swab were obtained from each calf for the identification of bacterial and viral pathogens. Genome-wide association analyses were conducted using four analytical approaches (EIGENSTRAT, EMMAX-GRM, GBLUP and FvR). The most strongly associated SNPs from each individual analysis were ranked and evaluated for concordance. The heritability of susceptibility to BRDC in pre-weaned Holstein calves was estimated.ResultsThe four statistical approaches produced highly concordant results for 373 top ranked SNPs that defined 126 chromosomal regions for the CA population. Similarly, in NM, 370 SNPs defined 138 genomic regions that were identified by all four approaches. When the two populations were combined (i.e., CA + NM) and analyzed, 324 SNPs defined 116 genomic regions that were associated with BRDC across all analytical methods. Heritability estimates for BRDC were 21% for both CA and NM as individual populations, but declined to 13% when the populations were combined.ConclusionsFour analytical approaches utilizing both single and multi-marker association methods revealed common genomic regions associated with BRDC susceptibility that can be further characterized and used for genomic selection. Moderate heritability estimates were observed for BRDC susceptibility in pre-weaned Holstein calves, thereby supporting the application of genomic selection to reduce the prevalence of BRDC in U.S. Holsteins.

In recent years, the scintillation properties of several cerium-doped rare earth oxyorthosilicate scintillators, [Ln.sub.2]Si[O.sub.5]:Ce where Ln = Y, La-Lu, have been reported and, in some cases, extensively studied [1]-[3]. In addition, binary and ternary compounds such as [(Lu,Y).sub.2]Si[O.sub.5]:Ce, [(Lu,Gd).sub.2]Si[O.sub.5] and [(Lu,Y,Gd).sub.2]Si[O.sub.5]:Ce have been reported [3]-[7]. All of these crystals have either monoclinic P or C structures with characteristic Si[O.sub.4] tetrahedra and trivalent cations occupying two unique crystallographic positions [8], [9]. The trivalent cerium activator ions are assumed to occupy the cation lattice sites and possibly interstitial positions as well. The excited 5d state of [Ce.sup.3+] is split into three observable levels with luminescence emission occurring only from the lowest 5d level to the 4f ground state (~3 eV) with a Stokes shift of ~0.5 eV. The bandgap is about 6 eV, and the index of refraction is close to 1.8, with some variation according to crystallographic direction. Despite these similarities, in somecases, differences in scintillation efficiency, decay time, rise time, and phosphorescence time profiles have been observed. In this paper, we combine thermoluminescence measurements with the temperature characteristic of scintillation efficiency between 10 and 350 K to determine the trapping levels that may influence the scintillation and phosphorescence properties of crystals of various compositions. Index Terms--[Lu.sub.2]Si[O.sub.5]:Ce, LSO, [(Lu,Y).sub.2]Si[O.sub.5]:Ce, LYSO, [(Lu,Gd).sub.2]Si[O.sub.5], LGSO, [(Lu,Y,Gd).sub.2]Si[O.sub.5]:Ce, LYGSO, oxyorthosilicate, scintillators, thermoluminescence.

A strong, broad-band excited-state absorption (ESA) between different configuration states has been revealed when a series of blue-green emitting molecular-complex materials was analyzed. This was done by using a configuration-coordinate model for suitability as possible media for tunable lasers. The ESA was found to overlap luminescence spectra. The characteristics of ESA and its cross sectional comparisons with those of other stimulated emission is discussed.