Inferences regarding hybridization rely on genetic markers to differentiate parental taxa from one another. Intersimple sequence repeat (ISSR) markers are based on single‐primer PCR reactions where ...the primer sequence is derived from di‐ and trinucleotide repeats. These markers have successfully been used to assay genetic variability among cultivated plants, but have not yet been tested in natural populations. We used genetic markers generated from eight ISSR primers to examine patterns of hybridization and purported examples of hybrid speciation in Penstemon (Scrophulariaceae) in a hybrid complex involving P. centranthifolius, P. grinnellii, P. spectabilis and P. clevelandii. This hybrid complex has previously been studied using three molecular data sets (allozymes, and restriction‐site variation of nuclear rDNA and chloroplast DNA). These studies revealed patterns of introgression involving P. centranthifolius, but were unsuccessful in determining whether gene flow occurs among the other species, and support for hypotheses of diploid hybrid speciation was also lacking. In this study, we were able to fingerprint each DNA accession sampled with one to three ISSR primers and most accessions could be identified with a single primer. We found population‐ and species‐specific markers for each taxon surveyed. Our results: (i) do not support the hybrid origin of P. spectabilis; (ii) do support the hypothesis that P. clevelandii is a diploid hybrid species derived from P. centranthifolius and P. spectabilis; and (iii) demonstrate that pollen‐mediated gene flow via hummingbird vectors is prevalent in the hybrid complex.
This paper describes a method for model predictive control (MPC) with model maintenance. A supervisor maintains the control model in real time by providing an estimate of disturbances and noise. A ...switch is triggered when the predictions of the control model deviate from disturbance estimate by more than a pre-determined amount. The predictive control algorithm described in the paper uses the innovation representation of a Markov–Laguerre model. A Monte Carlo study and an experiment show that good models and stable control are obtained. A simulation study based on models of a boiler–turbine unit shows that the algorithm can adapt to time-varying data. The performance is assessed using the area regulation (AR) test criterion currently adopted by PJM Interconnection LLC. The proposed adaptive MPC gives an AR test score of more than 90 with pressure fluctuations less than 3% even when the coal quality changes.
Diploid hybrid speciation in Penstemon (Scrophulariaceae) Wolfe, A.D. (Ohio State University, Columbus, OH.); Xiang, Q.Y; Kephart, S.R
Proceedings of the National Academy of Sciences - PNAS,
04/1998, Letnik:
95, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Hybrid speciation has played a significant role in the evolution of angiosperms at the polyploid level. However, relatively little is known about the importance of hybrid speciation at the diploid ...level. Two species of Penstemon have been proposed as diploid hybrid derivatives based on morphological data, artificial crossing studies, and pollinator behavior observations: Penstemon spectabilis (derived from hybridization between Penstemon centranthifolius and Penstemon grinnellii) and Penstemon clevelandii (derived from hybridization between P. centranthifolius and P. spectabilis). Previous studies were inconclusive regarding the purported hybrid nature of these species because of a lack of molecular markers sufficient to differentiate the parental taxa in the hybrid complex. We developed hypervariable nuclear markers using inter-simple sequence repeat banding patterns to test these classic hypotheses of diploid hybrid speciation in Penstemon. Each species in the hybrid complex was genetically distinct, separated by 10--42 species-specific inter-simple sequence repeat markers. Our data do not support the hybrid origin of P. spectabilis but clearly support the diploid hybrid origin of P. clevelandii. Our results further suggest that the primary reason diploid hybrid speciation is so difficult to detect is the lack of molecular markers able to differentiate parental taxa from one another, particularly with recently diverged species
Due to the emerging potential for trafficking of special nuclear material, research programs are investigating current capabilities of commercially available portable gamma ray detection systems. ...Presented in this paper are the results of three different portable high-purity germanium (HPGe) detectors used to identify short-lived fission products generated from thermal neutron interrogation of small samples of highly enriched uranium. Samples were irradiated at the Washington State University Nuclear Radiation Center’s 1 MW TRIGA reactor. The three portable, HPGe detectors used were the ORTEC MicroDetective
1
, the ORTEC Detective
2
, and the Canberra Falcon
3
. Canberra’s GENIE-2000 software was used to analyze the spectral data collected from each detector. Ultimately, these three portable detectors were able to identify a large range of fission products showing potential for material discrimination.
The objective of this paper is to review the scientific literature to identify on-farm factors that contribute to market weight pig transportation losses. Transportation of market weight pigs is an ...essential element to the multisite pork production model used in the United States. In 2011 alone, approximately 111 million market weight pigs were transported from the finishing site to the abattoir. For pigs, the marketing process can present a combination of potentially novel, physical, and/or unfamiliar experiences that can be stressful. If the pig cannot cope with these sequential and additive stressors, then an increased rate of transportation losses could occur with a detrimental effect on pork carcass value. Current yearly estimates for transport losses are 1 million pigs (1%). A variety of market weight pig and farm factors have been reported to detrimentally affect transportation losses. By understanding how pigs interact with their environment during marketing, researchers, producers, and personnel at the abattoir may begin to identify, prioritize, and attempt to minimize or eliminate these stressors. This process will ultimately decrease transportation losses, improve pork quality, and increase profitability.
The Comprehensive Nuclear Test Ban Treaty has remote radionuclide monitoring followed by an On Site Inspection (OSI) to clarify the nature of a suspect event as part of its verification regime. An ...important aspect of radionuclide measurements on site is the discrimination of other potential sources of similar radionuclides such as reactor accidents or medical isotope production. The Chernobyl and Fukushima nuclear reactor disasters offer two different reactor source term environmental inputs that can be compared against historical measurements of nuclear explosions. The comparison of whole-sample gamma spectrometry measurements from these three events and the analysis of similarities and differences are presented. This analysis is a step toward confirming what is needed for measurements during an OSI under the auspices of the Comprehensive Test Ban Treaty.
A boron carbide capsule was previously designed and tested by Pacific Northwest National Laboratory (PNNL) and Washington State University (WSU) for spectral-tailoring in mixed spectrum reactors. The ...presented work used this B
4
C capsule to create a fission product sample from the irradiation of highly enriched uranium (HEU) with a fast fission neutron spectrum. An HEU foil was irradiated inside of the capsule in WSU’s 1 MW TRIGA reactor at full power for 200 min to produce 5.8 × 10
13
fissions. After 3 days of cooling, the sample was shipped to PNNL for radiochemical separations and analysis by gamma and beta spectroscopy. Fission yields for products were calculated from the radiometric measurements and compared to measurements from thermal neutron induced fission (analyzed in parallel with the non-thermal sample at PNNL) and published evaluated fast-pooled and thermal nuclear data. Reactor dosimetry measurements were also completed to fully characterize the neutron spectrum and total fluence of the irradiation.
Recent human activities have spread numerous plant species across the globe, yet it is unclear to what degree historical human activities influenced plant dispersal. In western North America, ...Camassia quamash was one of the most important food plants for indigenous peoples, who transported its propagules either intentionally or accidentally. We investigated how human and natural dispersal might have contributed to the current pattern of spatial genetic structure in C. quamash by performing phylogeographical surveys at two geographical scales. We sequenced two noncoding regions of chloroplast deoxyribonucleic acid (DNA) in 226 individuals from 53 populations of C. quamash as well as 126 individuals from 21 populations of the non-food plant Zigadenus venenosus. Contrary to the expectation of anthropogenic transport, C. quamash populations did not exhibit weaker genetic structure than Z. venenosus populations. We also failed to find convincing evidence for signatures of transport. Instead, our data showed strong effects of past glaciation and geographical barriers of the mountains in the Cascade Range, Olympic Peninsula and Vancouver Island. West of the Cascades, the species appears to have largely migrated northward from a southern refugium after deglaciation, whereas few populations having a highly divergent haplotype might have survived in southwestern Washington. Our data suggest that despite substantial ethnobotanical evidence for anthropogenic transport, the current pattern of genetic structure of C. quamash does not show any detectable signatures of transport by indigenous peoples and is better understood as the result of natural dispersal processes.
Camassia is a genus of six bulb-forming species endemic to North America that have figured prominently in the culture and sustenance of native peoples. In western North America they form a ...conspicuous element of wet meadows and forest openings. Species and, especially, subspecies delimitations have been problematic. Further, several hypothesized phylogenetic and biogeographic scenarios for the origin and diversification of the genus remain untested. We estimated the phylogeny of Camassia using two noncoding plastid DNA regions: rpl16 intron and trnD—trnY—trnE—trnT spacers, with the goals of evaluating 1) the delimitation of species and 2) Gould's hypotheses for the origin of species and infraspecific taxa. Maximum parsimony and Bayesian analyses provided concordant estimates of the phylogeny consistent with the monophyly of eastern American C. scilloides and western American C. howellii and C. leichtlinii. Two western American species were found to be paraphyletic—C. cusickii weakly so, but C. quamash was strongly supported as paraphyletic to C. cnsickii, C. scilloides and C. angusta. Our results are largely consistent with Gould's views that the genus originated in southwestern Oregon and diversified through eastern migration, and that C. scilloides and C. cusickii are derived from within C. quamash. Despite evidence that Camassia species hybridize, by sampling sympatric populations we detected only a single case of introgression of plastid haplotypes. This study provides the first molecular phylogenetic and phylogeographic context for evaluating evolutionary process and trait variation in this iconic genus of western North America.
The objective of this paper is to review the scientific literature to identify on-farm factors that contribute to market weight pig transportation losses. Transportation of market weight pigs is an ...essential element to the multisite pork production model used in the United States. In 2011 alone, approximately 111 million market weight pigs were transported from the finishing site to the abattoir. For pigs, the marketing process can present a combination of potentially novel, physical, and/ or unfamiliar experiences that can be stressful. If the pig cannot cope with these sequential and additive stressors, then an increased rate of transportation losses could occur with a detrimental effect on pork carcass value. Current yearly estimates for transport losses are 1 million pigs (1%). A variety of market weight pig and farm factors have been reported to detrimentally affect transportation losses. By understanding how pigs interact with their environment during marketing, researchers, producers, and personnel at the abattoir may begin to identify, prioritize, and attempt to minimize or eliminate these stressors. This process will ultimately decrease transportation losses, improve pork quality, and increase profitability. PUBLICATION ABSTRACT
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