Managing Spotted Knapweed (Centaurea stoebe) Using Restoration Methods

This thesis project addressed the effectiveness of integrating ecological restoration into traditional mechanical and chemical methods of invasive species control. Spotted knapweed, an abundant invasive plant species at Camp Ripley Military Training Site, is capable of prolific reproduction, and therefore, causes great ecological distress to the native community it invades. The purpose of this research was to determine if spotted knapweed can be controlled by re-introducing native prairie grasses to the disturbed sites at Camp Ripley, and ideally, apply these findings to the methods of invasive species control in native prairies across central Minnesota. Furthermore, the sequence of the application of selective, broadleaf herbicide (Milestone) and native grass seeding was varied in order to determine the sequence of treatments most likely to decrease the density of spotted knapweed, increase the density of target native grass species, and decrease the percentage of bare soil visible. Three research plots were used in the experiment: two of which received the native grass seeding in conjunction with the selective, broadleaf herbicide in varied order, one of which received only broadleaf herbicide. Data analysis, at the conclusion of the experiment in October 2016, showed that ecological restoration as an integrated method of control did not effect the spotted knapweed density, nor did the varied sequence of treatment applications. The broadleaf herbicide, Milestone, was solely responsible for the decrease in spotted knapweed density. A negative consequence of using Milestone was a decrease in species richness, including a negligible amount of target native grass species and increase in nonnative grasses and forbs. Finally, bare soil visible was not decreased in the experimental plots receiving both native grass seed and herbicide application. A supplemental greenhouse experiment was conducted January through March 2017 in order to determine if Milestone was responsible for lack of native grass growth at the end of the field experiment. Similar experimental methods were used, with the addition of an experimental group that lengthened the amount of time between herbicide and grass seed application to four weeks. Data analysis after ten weeks of growth showed that Milestone negatively affected native grass seedlings, regardless of treatment sequence or length of time between applications. Due to the nature of native prairie restoration, it is recommended that the site continue to be monitored over subsequent years for potential target grass population growth. Also, further research is recommended to determine a more appropriate chemical to integrate into a restorative method of control. Ecologists and land managers play a critical, cooperative role in determining control methods that allow native prairies to remain healthy and intact in order to resist invasive species known to degrade them

Preliminary calibration of a generic scramjet combustor

The results of a preliminary investigation of the combustion of hydrogen fuel at hypersonic flow conditions are provided. The tests were performed in a generic, constant-area combustor model with test gas supplied by a free-piston-driven reflected-shock tunnel. Static pressure measurements along the combustor wall indicated that burning did occur for combustor inlet conditions of P(static) approximately equal to 19kPa, T(static) approximately equal to 1080 K, and U approximately equal to 3630 m/s with a fuel equivalence ratio approximately equal to 0.9. These inlet conditions were obtained by operating the tunnel with stagnation enthalpy approximately equal to 8.1 MJ/kg, stagnation pressure approximately equal to 52 MPa, and a contoured nozzle with a nominal exit Mach number of 5.5

The role of matrix cracks and fibre/matrix debonding on the stress transfer between fibre and matrix in a single fibre fragmentation test

The single fibre fragmentation test is commonly used to characterise the fibre/matrix interface. During fragmentation, the stored energy is released resulting in matrix cracking and/or fibre/matrix debonding. Axisymmetric finite element models were formulated to study the impact of matrix cracks and fibre/matrix debonding on the effective stress transfer efficiency (EST) and stress transfer length (STL). At high strains, plastic deformation in the matrix dominated the stress transfer mechanism. The combination of matrix cracking and plasticity reduced the EST and increased STL. For experimental validation, three resins were formulated and the fragmentation of an unsized and uncoupled E-glass fibre examined as a function of matrix properties. Fibre failure was always accompanied by matrix cracking and debonding. With the stiff resin, debonding, transverse matrix cracking and conical crack initiation were observed. With a lower modulus and lower yield strength resin the transverse matrix crack length decreased while that of the conical crack increased. (C) 2011 Elsevier Ltd. All rights reserved

The Response of Selected Temperate Forages to Increasing Summer Drought Conditions and High Summer Temperatures in Northern Victoria, Australia

In the dairy region of northern Victoria, Australia, the performance of temperate perennial dairy pastures is often poor over summer due to a combination of high temperatures and limited water availability that can restrict dry matter production and plant survival. A series of field experiments examined the effects of heat and restricted irrigation (as a consequence of drought) on the growth and nutritive characteristics of selected forage species, and whether survival under experimental conditions was influenced by plant genotype, irrigation and grazing management strategies, as well as endophyte presence. The major focus was on perennial ryegrass. Detailed sampling of perennial ryegrass (Lolium perenne L.), lucerne (Medicago sativa L.) and tall fescue (Festuca arundinacea Schreb) pastures on commercial farms during five extreme heat events (\u3e 35 oC) over summer 2018/2019, highlighted the impact of high temperatures on pasture nutritive parameters. In vitro dry matter digestibility and water soluble carbohydrate concentrations decreased by 0.2% units per degree rise in average maximum daily temperature from 23 to 40 ºC and neutral detergent fibre and acid detergent fibre concentrations increased by 0.2% and 0.15% units per degree, respectively. When a range of perennial ryegrass cultivars, hybrid ryegrasses and tall fescue cultivars were evaluated under full and restricted irrigation and two grazing strategies, few differences in net pasture accumulation over summer or survival were observed. The research highlighted the importance of maintaining plant density during periods of restricted irrigation to ensure plant recovery once irrigation or rainfall becomes available. No endophyte-ryegrass combinations were found to be better adapted to restricted water and high temperature conditions. The incidences of extreme heat events and low water availability are increasing in northern Victoria and this research will assist farmers to identify strategies to mitigate the negative effect of these conditions on the production and feed quality of perennial ryegrass-based pastures

Simplified Coalgebraic Trace Equivalence

The analysis of concurrent and reactive systems is based to a large degree on various notions of process equivalence, ranging, on the so-called linear-time/branching-time spectrum, from fine-grained equivalences such as strong bisimilarity to coarse-grained ones such as trace equivalence. The theory of concurrent systems at large has benefited from developments in coalgebra, which has enabled uniform definitions and results that provide a common umbrella for seemingly disparate system types including non-deterministic, weighted, probabilistic, and game-based systems. In particular, there has been some success in identifying a generic coalgebraic theory of bisimulation that matches known definitions in many concrete cases. The situation is currently somewhat less settled regarding trace equivalence. A number of coalgebraic approaches to trace equivalence have been proposed, none of which however cover all cases of interest; notably, all these approaches depend on explicit termination, which is not always imposed in standard systems, e.g. LTS. Here, we discuss a joint generalization of these approaches based on embedding functors modelling various aspects of the system, such as transition and braching, into a global monad; this approach appears to cover all cases considered previously and some additional ones, notably standard LTS and probabilistic labelled transition systems

Alterations in serum kynurenine pathway metabolites in individuals with high neocortical amyloid-β load: A pilot study

The kynurenine pathway (KP) is dysregulated in neuroinflammatory diseases including Alzheimer\u27s disease (AD), however has not been investigated in preclinical AD characterized by high neocortical amyloid-β load (NAL), prior to cognitive impairment. Serum KP metabolites were measured in the cognitively normal KARVIAH cohort. Participants, aged 65-90 y, were categorised into NAL+ (n = 35) and NAL- (n = 65) using a standard uptake value ratio cut-off = 1.35. Employing linear models adjusting for age and APOEϵ4, higher kynurenine and anthranilic acid (AA) in NAL+ versus NAL- participants were observed in females (kynurenine, p = 0.004; AA, p = 0.001) but not males (NALxGender, p = 0.001, 0.038, respectively). To evaluate the predictive potential of kynurenine or/and AA for NAL+ in females, logistic regressions with NAL+/- as outcome were carried out. After age and APOEϵ4 adjustment, kynurenine and AA were individually and jointly significant predictors (p = 0.007, 0.005, 0.0004, respectively). Areas under the receiver operating characteristic curves were 0.794 using age and APOEϵ4 as predictors, and 0.844, 0.866 and 0.871 when kynurenine, AA and both were added. Findings from the current study exhibit increased KP activation in NAL+ females and highlight the predictive potential of KP metabolites, AA and kynurenine, for NAL+. Additionally, the current study also provides insight into he influence of gender in AD pathogenesi

Plasma neurofilament light chain and amyloid-β are associated with the kynurenine pathway metabolites in preclinical Alzheimer\u27s disease

BACKGROUND: Blood markers indicative of neurodegeneration (neurofilament light chain; NFL), Alzheimer\u27s disease amyloid pathology (amyloid-β; Aβ), and neuroinflammation (kynurenine pathway; KP metabolites) have been investigated independently in neurodegenerative diseases. However, the association of these markers of neurodegeneration and AD pathology with neuroinflammation has not been investigated previously. Therefore, the current study examined whether NFL and Aβ correlate with KP metabolites in elderly individuals to provide insight on the association between blood indicators of neurodegeneration and neuroinflammation. METHODS: Correlations between KP metabolites, measured using liquid chromatography and gas chromatography coupled with mass spectrometry, and plasma NFL and Aβ concentrations, measured using single molecule array (Simoa) assays, were investigated in elderly individuals aged 65-90 years, with normal global cognition (Mini-Mental State Examination Score ≥ 26) from the Kerr Anglican Retirement Village Initiative in Ageing Health cohort. RESULTS: A positive correlation between NFL and the kynurenine to tryptophan ratio (K/T) reflecting indoleamine 2,3-dioxygenase activity was observed (r = .451, p \u3c .0001). Positive correlations were also observed between NFL and kynurenine (r = .364, p \u3c .0005), kynurenic acid (r = .384, p \u3c .0001), 3-hydroxykynurenine (r = .246, p = .014), anthranilic acid (r = .311, p = .002), and quinolinic acid (r = .296, p = .003). Further, significant associations were observed between plasma Aβ40 and the K/T (r = .375, p \u3c .0005), kynurenine (r = .374, p \u3c .0005), kynurenic acid (r = .352, p \u3c .0005), anthranilic acid (r = .381, p \u3c .0005), and quinolinic acid (r = .352, p \u3c .0005). Significant associations were also observed between plasma Aβ42 and the K/T ratio (r = .215, p = .034), kynurenic acid (r = .214, p = .035), anthranilic acid (r = .278, p = .006), and quinolinic acid (r = .224, p = .027) in the cohort. On stratifying participants based on their neocortical Aβ load (NAL) status, NFL correlated with KP metabolites irrespective of NAL status; however, associations between plasma Aβ and KP metabolites were only pronounced in individuals with high NAL while associations in individuals with low NAL were nearly absent. CONCLUSIONS: The current study shows that KP metabolite changes are associated with biomarker evidence of neurodegeneration. Additionally, the association between KP metabolites and plasma Aβ seems to be NAL status dependent. Finally, the current study suggests that an association between neurodegeneration and neuroinflammation manifests in the periphery, suggesting that preventing cytoskeleton cytotoxicity by KP metabolites may have therapeutic potential

Systemic perturbations of the kynurenine pathway precede progression to dementia independently of amyloid-β

Increasing evidence suggests that kynurenine pathway (KP) dyshomeostasis may promote disease progression in dementia. Studies in Alzheimer\u27s disease (AD) patients confirm KP dyshomeostasis in plasma and cerebrospinal fluid (CSF) which correlates with amyloid-β and tau pathology. Herein, we performed the first comprehensive study assessing baseline levels of KP metabolites in participants enrolling in the Australian Imaging Biomarkers Flagship Study of Aging. Our purpose was to test the hypothesis that changes in KP metabolites may be biomarkers of dementia processes that are largely silent. We used a cross-sectional analytical approach to assess non-progressors (N = 73); cognitively normal (CN) or mild cognitive impairment (MCI) participants at baseline and throughout the study, and progressors (N = 166); CN or MCI at baseline but progressing to either MCI or AD during the study. Significant KP changes in progressors included increased 3-hydroxyanthranilic acid (3-HAA) and 3-hydroxyanthranilic acid/anthranilic acid (3-HAA/AA) ratio, the latter having the largest effect on the odds of an individual being a progressor (OR 35.3; 95% CI between 14 and 104). 3-HAA levels were hence surprisingly bi-phasic, high in progressors but low in non-progressors or participants who had already transitioned to MCI or dementia. This is a new, unexpected and interesting result, as most studies of the KP in neurodegenerative disease show reduced 3-HAA/AA ratio after diagnosis. The neuroprotective metabolite picolinic acid was also significantly decreased while the neurotoxic metabolite 3-hydroxykynurenine increased in progressors. These results were significant even after adjustment for confounders. Considering the magnitude of the OR to predict change in cognition, it is important that these findings are replicated in other populations. Independent validation of our findings may confirm the utility of 3-HAA/AA ratio to predict change in cognition leading to dementia in clinical settings

The multidrug-resistant PMEN1 pneumococcus is a paradigm for genetic success.

To access publisher´s full text version of this article. Please click on the hyperlink in Additional Links field.Streptococcus pneumoniae, also called the pneumococcus, is a major bacterial pathogen. Since its introduction in the 1940s, penicillin has been the primary treatment for pneumococcal diseases. Penicillin resistance rapidly increased among pneumococci over the past 30 years, and one particular multidrug-resistant clone, PMEN1, became highly prevalent globally. We studied a collection of 426 pneumococci isolated between 1937 and 2007 to better understand the evolution of penicillin resistance within this species. We discovered that one of the earliest known penicillin-nonsusceptible pneumococci, recovered in 1967 from Australia, was the likely ancestor of PMEN1, since approximately 95% of coding sequences identified within its genome were highly similar to those of PMEN1. The regions of the PMEN1 genome that differed from the ancestor contained genes associated with antibiotic resistance, transmission and virulence. We also revealed that PMEN1 was uniquely promiscuous with its DNA, donating penicillin-resistance genes and sometimes many other genes associated with antibiotic resistance, virulence and cell adherence to many genotypically diverse pneumococci. In particular, we describe two strains in which up to 10% of the PMEN1 genome was acquired in multiple fragments, some as long as 32 kb, distributed around the recipient genomes. This type of directional genetic promiscuity from a single clone to numerous unrelated clones has, to our knowledge, never before been described. These findings suggest that PMEN1 is a paradigm of genetic success both through its epidemiology and promiscuity. These findings also challenge the existing views about horizontal gene transfer among pneumococci

“Some men deeply hate women, and express that hatred freely”: examining victims’ experiences and perceptions of gendered hate crime

Extensive debate about the place of gender within the hate crime policy domain has been fuelled by national victimisation surveys indicating people’s experiences of ‘gender hate crime’ coupled with Nottinghamshire Police’s decision to begin categorising misogynistic street harassment as a form of hate crime. Drawing on the results of an online survey of 85 respondents, this article explores people’s experiences of gender-related victimisation as ‘hate crimes’. The analysis demonstrates how participants relate their experiences to the hate crime concept, their perceptions on punishment and reporting to the police, and also wider impacts on their recovery processes. This paper provides a timely contribution towards current debates around using the existing hate crime model for addressing crimes motivated by gender hostility