2,274 research outputs found
On the coefficients of differentiated expansions of ultraspherical polynomials
A formula expressing the coefficients of an expression of ultraspherical polynomials which has been differentiated an arbitrary number of times in terms of the coefficients of the original expansion is proved. The particular examples of Chebyshev and Legendre polynomials are considered
Conforming Chebyshev spectral collocation methods for the solution of laminar flow in a constricted channel
The numerical simulation of steady planar two-dimensional, laminar flow of an incompressible fluid through an abruptly contracting channel using spectral domain decomposition methods is described. The key features of the method are the decomposition of the flow region into a number of rectangular subregions and spectral approximations which are pointwise C(1) continuous across subregion interfaces. Spectral approximations to the solution are obtained for Reynolds numbers in the range 0 to 500. The size of the salient corner vortex decreases as the Reynolds number increases from 0 to around 45. As the Reynolds number is increased further the vortex grows slowly. A vortex is detected downstream of the contraction at a Reynolds number of around 175 that continues to grow as the Reynolds number is increased further
Present and Future Tall Fescue Varieties
Tall fescue has played a key role in forage production over the past century in the USA. It has other uses besides forage applications, such as turf, mine reclamation, and highway rights-of-way, but in this presentation we will focus on forage varieties. Several hundred turf-type tall fescue varieties have been developed over the past 30 years, mainly by private seed companies using material from Reed Funk at Rutgers University in New Jersey. Forage varieties aren’t as numerous. I will discuss some of the older and current forage tall fescue varieties, and finish by discussing the newest varieties, and those that are in the pipeline that you will be seeing in the next few years
What Grasses Work Best with Alfalfa?
Alfalfa is the queen of forages, but many situations exist where it is desirable or necessary to grow alfalfa in a mixture with a forage grass rather in monoculture. Some of the reasons to grow grass with alfalfa are: improved yield (in terms of tons of dry matter produced), better seasonal yield distribution, better weed control, potential pest reduction, erosion prevention, bloat risk reduction, and accelerated hay-drying rates. Conversely, there are some factors that favor alfalfa monoculture. These include: lower forage quality, especially in terms of protein content; more difficult management requirements (herbicide use, fertilization, and harvest timing); and, lower yields in mixtures in practice than with alfalfa alone.
Many grasses have been used in mixtures with alfalfa. From the range of forage grasses used by producers in Kentucky, most have some potential as companions to alfalfa. Several grasses have been use successfully in mixtures with alfalfa and other forage legumes, particularly red clover
Western equine encephalitis virus: neuroinvasion, pathogenesis, and immunomodulatory treatment strategies
2013 Fall.Includes bibliographical references.Western equine encephalitis virus (WEEV; Alphavirus) is a mosquito-borne virus that can cause severe encephalitis in humans and equids. WEEV is closely-related to eastern equine encephalitis virus (EEEV) and may model similar pathogenesis in a mouse model. Previous studies have shown that intranasal infection of outbred CD-1 mice with the WEEV McMillan (McM) strain result in high mortality within 4 days of infection, thus providing a model of exposure to airborne encephalitic alphavirus. In addition, WEEV McM causes high mortality within 5-7 days following peripheral inoculation of mice. Therefore, WEEV McM may be used to model infection following exposure to infected mosquitos. The route of WEEV entry into the central nervous system (CNS) is not well-understood. In the studies presented here, bioluminescence (BLM) imaging and recombinant reporter viruses based on WEEV McM were applied to detect and track virus in mice following intranasal or subcutaneous inoculation, and used to determine correlation between BLM and viral titer. Additionally, histopathology analysis was guided by corresponding BLM images and used to identify specific CNS regions affected during infection. The major findings from these studies indicate that WEEV McM uses a different route for entry into the CNS for each of the two inoculation methods (intranasal or footpad). Intranasal challenge resulted in neuroinvasion occurring primarily through cranial nerves, mainly in the olfactory tract. Olfactory bulb neurons were initially infected followed by spread of the infection into different regions of the brain. WEEV distribution was confirmed by immunohistochemistry as having marked neuronal infection but very few infected non-neuronal glial cells. Axons displayed infection patterns consistent with viral dissemination along the neuronal axis. The trigeminal nerve served as an additional route of neuroinvasion showing significant FLUC expression within the brainstem. Neuroinvasion from footpad inoculation demonstrated a consistent pattern in the spatiotemporal distribution of virus among the imaged brains, none of which involved the olfactory bulb. These studies support the hypothesis that neuroinvasion of WEEV likely occurs in areas of the CNS where the blood-brain barrier is naturally absent. These areas include the median eminence of hypothalamus (hypothalamic output), posterior pituitary, pineal body, and the area postrema. There are no antiviral therapies against alphaviral disease and current vaccine strategies target only a single alphavirus species. In an effort to develop new tools for a broader response to outbreaks, a novel alphavirus vaccine comprised of cationic-lipid-nucleic acid complexes (CLNCs) and the ectodomain of WEEV E1 protein (E1ecto) was designed and tested. Interestingly, the CLNC component alone had therapeutic efficacy as it increased survival of CD-1 mice following lethal WEEV infection. Immunization with the CLNC-WEEV E1ecto mixture (lipid-antigen-nucleic acid complexes; LANACs) using a prime/boost regimen provided strong protection in mice challenged with WEEV subcutaneously, intranasally, or via mosquito. In addition, the LANAC immunization protocol significantly increased survival of mice following intranasal or subcutaneous challenge with EEEV, indicating potential as a 'pan-alphavirus' vaccine candidate. Mice immunized with LANAC mounted a strong humoral immune response, but did not produce neutralizing antibodies
Working for justice: the life history reflections of privileged college student social justice allies
This phenomenological life history study examined the dynamics that led privileged college students to engage in social justice work. I explored how privileged college students were led to understand how individuals get opportunities in life and ultimately achieve success. Also, I explored what moments or elements caused participants to question what they had learned and what barriers they faced to engaging in work for justice. All findings contributed to understanding what led privileged college students to engage in work for a more just environment. Using the social construction of dominant group privilege and ally development theory as the theoretical frameworks to guide this study, I analyzed how participants came to see injustice within the context of their privileged identity and why, unlike many of their peers, they chose to work on changing a social system from which they benefitted.
In all, nine students holding privileged identities participated in three qualitative life history interviews each through which data for the study were collected. Profiles of each participant were developed from the data. The data were then transcribed, coded, analyzed, and organized into emerging themes. The findings revealed that a search for authenticity, environmental influences, a critical event, or experience as other first made privileged students aware of injustice. Barriers to participant engagement reported most often included not understanding their role, a general lack of awareness about injustice, others influential in their lives lacking awareness, and the absence of skills interacting with people who held diverse identities and in doing effective work on justice issues. Finally, educational institutions had significant influence on participant awareness of injustice issues, the need to advocate for change, and ultimately their decisions to take action. Specifically, college curriculum, peer interactions with those holding diverse identities, and co-curricular engagement opportunities were cited as having an impact on participant decisions to engage in justice work.
Finally, I discussed ways these findings contributed to the existing literature and shared recommendations for future practice. I concluded with suggestions for future research to further expand our understanding of college student ally behavior development
\u27Lacefield MaxQll\u27 Novel Tall Fescue
The goal of deploying novel endophyte strains in tall fescue varieties has been to achieve forage yields, stress tolerance, and persistence similar to toxic endophyte tall fescue varieties (mainly ‘Kentucky 31’ endophyte infected with the common toxic endophyte strain), but with the superior animal performance results seen with endophyte-free tall fescue varieties or other non-toxic forage species (orchardgrass, alfalfa, etc.). In addition to better stand persistence, less weed encroachment has been reported in novel endophyte (and toxic endophyte) tall fescue varieties compared to their endophyte-free versions (Rudgers et al., 2010; Bouton et al., 2002). The improved competitive ability of endophyte-containing tall fescue populations in part may be due to reduced herbivory by insects (Vicari et al. 2002). Most novel endophyte strains have reduced or no ergot alkaloid production compared to the common toxic endophyte strain found in Kentucky 31, but they still produce other types of alkaloids with insecticidal properties but not anti-mammalian effects. Other research has shown that novel endophyte tall fescue plantings may resist re-colonization or contamination by toxic-endophyte tall fescue from the soil seed bank or introduction of toxic endophyte-infected seed by other means (feeding hay, grazing seed heads of toxic endophyte tall fescue) (Barker et al., 2005)
New Tall Fescue Varieties for the Future
Over the past few decades forage producers have seen several major changes in varieties of tall fescue. From the days of Kentucky 31 being the predominant variety, the first change was the first generation of endophyte-free tall fescue varieties. For many growers, these have been useful additions, especially when coupled with rotational grazing to reduce the risks of overgrazing, and practices of eradication of stands of toxic endophyte pastures and prevention of the reintroduction of toxic endophyte tall fescue seed into stands of endophyte-free varieties. However, overall these varieties often lacked the persistence of Kentucky 31 infected with the common toxic strain of endophyte, and disappointed many early adopters. In the 25-30 years since the first generation of endophyte-free varieties, plant breeders have made progress in developing additional populations with a greater range of diversity, and improved varieties are still being developed, and will be developed
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