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Although reptiles and amphibians have long been used in biomedical research, few in the arena understand their health and husbandry needs. The author provides an introduction to the successful maintenance of reptiles and amphibian...
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Although reptiles and amphibians have long been used in biomedical research, few in the arena understand their health and husbandry needs. The author provides an introduction to the successful maintenance of reptiles and amphibians in the laboratory environment.
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Several single nucleotide polymorphisms (SNP) in the bovine CXCR1 gene have been implicated in resistance to mastitis and milk somatic cell counts in several sample populations of Holstein dairy cows. As such, a more thorough unde...
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Several single nucleotide polymorphisms (SNP) in the bovine CXCR1 gene have been implicated in resistance to mastitis and milk somatic cell counts in several sample populations of Holstein dairy cows. As such, a more thorough understanding of SNP present in and near the bovine CXCR1 gene is needed. This study identified 36 SNP in the coding region and surrounding sequences of CXCR1 in 88 Holstein dairy cows. Four SNP induced amino acid changes and 1 SNP an early stop codon. Two amino acid changes occur in the third intracellular loop and C-terminus in locations tied to intracellular signaling. The 36 SNP could be subdivided into 4 separate linkage groups. Using representative or 'tag' SNP from each linkage group, haplotypes or the combination of SNP found on a single allele were generated to increase the specificity of an animal's genetic background. Four haplotypes were identified that represented 99% of the sample population. The haplotypes generated using tag SNP agreed with haplotypes generated from SNP causing amino acid changes. In conclusion, the CXCR1 gene is highly polymorphic and has potential implications towards genetic selection and understanding host factors that increase the risk of infection. (C) 2011 Elsevier B.V. All rights reserved.
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Agricultural education has traditionally provided rich learning experiences for secondary school students; however, less attention has been paid to the learning experiences preservice agricultural education teachers utilize and pr...
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Agricultural education has traditionally provided rich learning experiences for secondary school students; however, less attention has been paid to the learning experiences preservice agricultural education teachers utilize and provide secondary school students during the student teaching internship. This study sought to describe the learning activities preservice teachers utilize during instruction and assess preservice teachers' self-perception of preparedness in technical content knowledge and teaching methods after completing their student teaching internship. A majority of the preservice teachers used student-centered activities with the greatest frequency, and did not rely on one category of learning activities a majority of the time. This finding is encouraging since variety is a characteristic of effective teaching, and the types of learning activities utilized support the philosophical beliefs of agricultural education. On the other hand, preservice teachers identified agricultural mechanics, biotechnology, wildlife and fisheries management, and veterinary science as technical content areas in which they possessed less than appropriate content knowledge. A majority of the preservice teachers also perceived themselves as not prepared in instructional methods for wildlife and fisheries management and veterinary sciences. We recommend these technical content areas and pedagogical deficiencies be considered high priorities when developing in-service professional development for new teachersin Florida.
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The objective of our investigation was to acquire information on the association between molecular markers and foliage color in flowering dogwood in order to improve our understanding of the inheritance of this trait and to make p...
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The objective of our investigation was to acquire information on the association between molecular markers and foliage color in flowering dogwood in order to improve our understanding of the inheritance of this trait and to make possible early selection of red foliage genotypes in breeding programs. A segregating pseudo-F population of 94 individuals of flowering dogwood (Cornus florida L.), together with 255 simple sequence repeat markers, was used to identify putative quantitative trait loci (QTL) for foliage color. Foliage color segregated into green- and red-leaved phenotypes and was visually rated for color on five spring dates over 3 years (2007-2009). Repeated measures single-marker categorical analysis of variance (ANOVA) identified four putative QTL (CF309C, CF792A, CF367B, and CF367C) on three linkage groups. Single-marker categorical ANOVA was then used to determine stability of QTL across dates. We identified different QTL, found a low percentage of phenotypic variance explained by the QTL, and detected QTL instability over time, providing evidence of the complex genetics for red pigment expression in flowering dogwood.
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The objective of our investigation was to acquire information on the association between molecular markers and foliage color in flowering dogwood in order to improve our understanding of the inheritance of this trait and to make p...
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The objective of our investigation was to acquire information on the association between molecular markers and foliage color in flowering dogwood in order to improve our understanding of the inheritance of this trait and to make possible early selection of red foliage genotypes in breeding programs. A segregating pseudo-F population of 94 individuals of flowering dogwood (Cornus florida L.), together with 255 simple sequence repeat markers, was used to identify putative quantitative trait loci (QTL) for foliage color. Foliage color segregated into green- and red-leaved phenotypes and was visually rated for color on five spring dates over 3 years (2007-2009). Repeated measures single-marker categorical analysis of variance (ANOVA) identified four putative QTL (CF309C, CF792A, CF367B, and CF367C) on three linkage groups. Single-marker categorical ANOVA was then used to determine stability of QTL across dates. We identified different QTL, found a low percentage of phenotypic variance explained by the QTL, and detected QTL instability over time, providing evidence of the complex genetics for red pigment expression in flowering dogwood.
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摘要 :
The objective of our investigation was to acquire information on the association between molecular markers and foliage color in flowering dogwood in order to improve our understanding of the inheritance of this trait and to make p...
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The objective of our investigation was to acquire information on the association between molecular markers and foliage color in flowering dogwood in order to improve our understanding of the inheritance of this trait and to make possible early selection of red foliage genotypes in breeding programs. A segregating pseudo-F2 population of 94 individuals of flowering dogwood (Cornus florida L.), together with 255 simple sequence repeat markers, was used to identify putative quantitative trait loci (QTL) for foliage color. Foliage color segregated into green- and red-leaved phenotypes and was visually rated for color on five spring dates over 3 years (2007–2009). Repeated measures single-marker categorical analysis of variance (ANOVA) identified four putative QTL (CF309C, CF792A, CF367B, and CF367C) on three linkage groups. Single-marker categorical ANOVA was then used to determine stability of QTL across dates. We identified different QTL, found a low percentage of phenotypic variance explained by the QTL, and detected QTL instability over time, providing evidence of the complex genetics for red pigment expression in flowering dogwood.
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Net annual soil carbon change, fossil fuel emissions from cropland production, and cropland net primary production were estimated and spatially distributed using land cover defined by NASA's moderate resolution imaging spectroradi...
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Net annual soil carbon change, fossil fuel emissions from cropland production, and cropland net primary production were estimated and spatially distributed using land cover defined by NASA's moderate resolution imaging spectroradiometer (MODIS) and by the USDA National Agricultural Statistics Service (NASS) cropland data layer (CDL). Spatially resolved estimates of net ecosystem exchange (NEE) and net ecosystem carbon balance (NECB) were developed. The purpose of generating spatial estimates of carbon fluxes, and the primary objective of this research, was to develop a method of carbon accounting that is consistent from field to national scales. NEE represents net on-site vertical fluxes of carbon. NECB represents all on-site and off-site carbon fluxes associated with crop production. Estimates of cropland NEE using moderate resolution (～1 km~2) land cover data were generated for the conterminous United States and compared with higher resolution (30-m) estimates of NEE and with direct measurements of CO_2 flux from croplands in Illinois and Nebraska, USA. Estimates of NEE using the CDL (30-m resolution) had a higher correlation with eddy covariance flux tower estimates compared with estimates of NEE using MODIS. Estimates of NECB are primarily driven by net soil carbon change, fossil fuel emissions associated with crop production, and CO_2 emissions from the application of agricultural lime. NEE and NECB for U.S. croplands were -274 and 7 Tg C/yr for 2004, respectively. Use of moderate- to high-resolution satellite-based land cover data enables improved estimates of cropland carbon dynamics.
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Field studies that address the production of lignocellulosic biomass as a source of renewable energy provide critical data for the development of bioenergy crop models. A literature survey revealed that 14 models have been used fo...
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Field studies that address the production of lignocellulosic biomass as a source of renewable energy provide critical data for the development of bioenergy crop models. A literature survey revealed that 14 models have been used for simulating bioenergy crops including herbaceous and woody bioenergy crops, and for crassula- cean acid metabolism(CAM)crops. These models simulate field-scale production of biomass for switchgrass(ALMANAC, EPIC, and Agro-BGC), miscanthus(MISCANFOR, MISCANMOD, and WIMOVAC), sugarcane(APSIM, AUSCANE, and CANEGRO), and poplar and willow(SECRETS and 3PG). Two models are adaptations of dynamic global vegetation models and simulate biomass yields of miscanthus and sugarcane at regional scales(Agro-IBIS and LPJmL). Although it lacks the complexity of other bioenergy crop models, the environ- mental productivity index(EPI)is the only model used to estimate biomass production of CAM(Agave and Opuntia)plants. Except for the EPI model, all models include representations of leaf area dynamics, phenology, radiation interception and utilization, biomass production, and partitioning of biomass to roots and shoots. A few models simulate soil water, nutrient, and carbon cycle dynamics, making them especially useful for assess- ing the environmental consequences(e.g., erosion and nutrient losses)associated with the large-scale deploy- ment of bioenergy crops. The rapid increase in use of models for energy crop simulation is encouraging; however, detailed information on the influence of climate, soils, and crop management practices on biomass pro- duction is scarce. Thus considerable work remains regarding the parameterization and validation of process- based models for bioenergy crops; generation and distribution of high-quality field data for model development and validation; and implementation of an integrated framework for efficient, high-resolution simulations of biomass production for use in planning sustainable bioenergy systems.
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This paper summarizes the results of an update to a resource assessment, published in 2005, commonly referred to as the Billion-Ton Study (BTS). The updated results are consistent with the 2005 BTS in terms of overall magnitude. T...
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This paper summarizes the results of an update to a resource assessment, published in 2005, commonly referred to as the Billion-Ton Study (BTS). The updated results are consistent with the 2005 BTS in terms of overall magnitude. The 2005 BTS projected between 860 and 1240 Tg of biomass available in the 2050 timeframe, while the Billion-Ton Update (BT2), for a price of 66 $ Mg~(-1), projected between 994 and 1483 Tg in 2030. For the BT2, forest residue biomass potential was determined to be less owing to tighter restrictions on forest residue supply including restrictions due to limited projected increase in traditional harvest for pulpwood and sawlogs. Crop residue potential was also determined to be less because of the consideration of soil carbon and not allowing residue removal from conventionally tilled corn acres. Energy crop potential was estimated to be much greater largely because of land availability and modeling of competition among various competing uses of the land. Generally, the scenario assumptions in the updated assessment are much more plausible to show a "billion-ton" resource, which would be sufficient to displace 30% or more of the country's present petroleum consumption and provide more than enough biomass to meet the 2022 requirements of the Renewable Fuel Standard.
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A team of nine researchers from the United States spent 10 days exploring the formal agricultural education system in Trinidad and Tobago from primary education through postgraduate education. Data were collected from interviews a...
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A team of nine researchers from the United States spent 10 days exploring the formal agricultural education system in Trinidad and Tobago from primary education through postgraduate education. Data were collected from interviews and observations fromstudents, teachers/instructors, and agricultural producers. The team concluded that (a) the people in Trinidad and Tobago involved in agriculture (teachers, students, and producers) are passionate about agriculture, but believe that the general public demeans agricultural workers and work; (b) Trinidad and Tobago has the capacity to develop a well-trained workforce through a comprehensive agricultural education system that spans from primary education to doctoral instruction, however there was little interaction between the various educational systems; and (c) pedagogical training for agriculture educators at all levels can be improved. Furthermore, conclusions related to nine specific areas of interest are discussed and six recommendations for improving the formal agricultural education system in Trinidad and Tobago are provided. As an exploratory study, the findings and conclusions drawn only begin to shed light on ways to improve human capacity development in Trinidad and Tobago. Thus, future research is warranted to further understand and improve Trinidad and Tobago's human capacity development efforts.
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