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Finite difference method on 1D and 2D Riemann problems for Euler equations with different state of equations
Get PDFWe discussed the finite difference WENO5 scheme on the 1D and 2D compressible Euler equations. The 1D Chaplygin gas system with a constant external force led to two kinds of solutions: contact discontinuity and delta shock. A convex set and a limiter were applied to the 2D pressureless system to preserve the positivity of the density function and the boundedness of the velocity field. A global condition on the density function was applied to maintain the scheme’s high order of accuracy, as well as to reduce the computational cost
The effects of training status and recovery time on the reconstitution of impulse above electrically stimulated critical torque
Get PDFFatigue represents a reduction in the desired or expected muscular force (Porter, 1981) often as a result of intense or prolonged exercise. Critical power (CP) provides a framework to understand fatigue and exercise intolerance, in that it represents a threshold power output below which it is possible to maintain steady-state exercise. Above CP time-to-exhaustion occurs in a predictable manner often termed the “power-duration relationship” whereby the higher the work rate is above CP, the shorter the exercise duration. W’ represents the curvature constant for work performed above CP. It represents a fixed amount of total work that can be performed before fatigue is reached. Little is known about W’ reconstitution and its rate (kinetics) of recovery during and following exercise, but has been linked to the recovery of muscle phosphocreatine concentrations and state of aerobic training. No data exist on the kinetics of W’ reconstitution using isometric contractions where it is termed impulse above critical torque (IACT) and the extent to which it is affected by training state and peripheral fatigue. The purpose of this study was to examine the time-course of the reconstitution of IACT’ following its depletion during electrically evoked isometric exercise examine the effects of aerobic training status on IACT reconstitution. Twenty six participants (10 trained, 16 untrained) completed 4 bouts of electrically stimulated exercise consisting of 75 contractions using a 2-sec:2-sec on/off duty cycle of the knee extensors. IACT was calculated as the sum of the area under the torque-time curve above the critical torque (CT) across all contractions; determined as the average of the final 6 contractions. Five or 15 minutes of rest was provided and then exercise as repeated. A mixed methods ANOVA revealed the three-way interaction among rest period (5-min vs. 15-min), exercise bout (1st or second on that day), and training status was not significant (p=0.79). A significant (p < 0.001) main effect for exercise bout was found with values from bout 2 being reduced (~21%) compared to round 1 to a similar extent regardless of training status or rest provided. The findings of this study are in contrast to previous studies that found that additional rest and higher aerobic training status lead to faster recovery of W’/IACT. Our findings clearly indicate that peripheral occurs during exercise and that it does not recovery, even when 15-min of rest are provided
Farm attacks in South Africa: an international comparison of farm crimes
Get PDFThis qualitative study focused on violent farm attacks in South Africa and the uniqueness of these crimes to that country. This was accomplished by reviewing all available literature on not only South African farm attacks but on agricultural crimes which occur there as well. The data was gathered through an extensive literature review of published reports, news articles, books, journals, government records, and collaboration with fellow researchers in South Africa on this topic. A detailed comparison of the characteristics of these crimes supports the conclusion that South African farm attacks present a unique crime problem unlike any other crime problem in the world. At present the government of South Africa does not view these violent rural crimes as a unique crime problem, but rather addresses them in the context of violent crimes in general. No special recognition or resources are applied to the problem which is only increasing in number of occurrences and violence. This study supports the argument that violent South African farm crimes present a unique challenge to law enforcement and should be addressed as a priority crime problem by the government of South Africa. In an effort to identify and propose strategies, the rural crime problems of Australia and the United States were examined for the most effective "best practices." This study identifies several which may be viable strategies for the problem in South Africa. Acknowledging this problem and formulating political policies and law enforcement strategies for combating these crimes will enhance the security and livelihood of rural farmers in South Africa, improve government-citizen relations, and provide an improved economic impact for the people of South Africa
Risk-based evaluation and management of cyber-physical-social systems during pandemic crisis
Get PDFThis research focuses on risk-based evaluation and management of cyber-physical-social systems during a pandemic crisis. The ongoing novel coronavirus (COVID-19) epidemic has caused serious challenges for the world’s countries. The health and economic crisis caused by the COVID-19 pandemic highlights the necessity for a deeper understanding and investigation of the best mitigation policy. While different control strategies in the early stages, such as lockdowns and school and business closures, have helped decrease the number of infections, these strategies have had an adverse economic impact on businesses and some controversial impacts on social justice. Therefore, optimal timing and scale of closure and reopening strategies are required to prevent both different waves of the pandemic and the negative socio-economic impact of control strategies. To maximize the effectiveness of the controlling policies during a major crisis like a pandemic, we propose two mathematical frameworks which optimize the contorting policy while considering three sets of important factors, including the epidemiologic, economic, and social impact of the pandemic. Each formulation quantifies the epidemiologic impact using a modified SIRD (susceptible-infected-recovered-deceased) model which captures the number of infected, recovered, immune, and deceased populations. The two formulations propose different approaches for measuring the social and economic impacts of the pandemic.
In the first formulation, the economic impact is a twofold measure, first the unmet demand because of supply perturbation (due to industry closure), and the second is the local business shrinkage because of demand perturbation (due to the state closure). The modified SIRD model is combined with a multi-commodity maximum network flow problem (MNFP) in which the unmet demand is measured in a network of states and industries. The proposed formulation is implemented on a dataset that includes 11 states, the District of Columbia (including the states in New England and the mid-Atlantic), and 19 industries in the US.
In the second formulation, the economic impact is measured using the supply side multi-regional inoperability input-output model, accounting for the inoperability of each industry to satisfy the demand of final consumers and other industries, due to its closure. Also, the second formulation measures the social impact of the pandemic policy, by incorporating the vulnerability of social communities to get infected due to state opening or to lose their job due to the closure of the state. We test the efficacy of proposed formulations on the real data set of COVID-19 applicable to 50 states, the District of Columbia, and 19 industries.
Both formulations are multi-objective mixed integer programming with three objectives which are solved using the augmented ε-constraint approach. The final pandemic policy is selected from the set of Pareto-optimal solutions based on the least cubic distance of the solution from the optimal value of each objective. The Pareto-optimal solutions suggest that for any control decision (state and industry closure or reopening), the economic impact and the epidemiologic impact change in the opposite direction, and it is more effective to close most states while keeping the majority of industries open. For each Pareto optimal solution, the unmet demand and the propagation of inoperability to the industries and states can be tracked down. This will give a holistic view of the impact of the pandemic policy on the health, economy, and social justice aspects of the country
Protecting Artists’ Moral Rights in the U.S. Legal Context
No full textThe three chapters of this dissertation work together and build on each other to make an argument for stronger uniform artists’ moral rights protections in the United States legal system. The current system provides inconsistent protection in a narrow subset of instances and fails to adequately protect moral rights. Many artists lack protections either due to the type of work they produce or due to lack of stature and bargaining power. I argue that by adopting an intimacy-based motivation for protecting moral rights the US legal system could develop laws that sufficiently protect moral rights more broadly and more fairly. This system would guarantee a minimum level of protection for all artists who satisfy the requirements of the intimacy account and provide artists in the United States the same level of protections enjoyed by artists in other countries.
This work fills current gaps in the philosophical and legal literature, as well as offering new insights into areas that have been previously discussed. There are two main philosophers currently working in and around the area of artists’ moral rights and copyright law: K.E. Gover and Darren Hudson Hick. Gover focuses on moral rights while not suggesting how these rights should be legally protected and Hick discusses legal protections without discussing moral rights. My work engages with both and provides a bridge, both discussing moral rights and legal application.
In Chapter One, I offer a novel justification for the protection of artists’ moral rights based explicitly in the intimate relationship that connects artists to their work. The intimacy account of artists’ moral right rights builds from two more general intimacy accounts. Charles Fried’s intimacy account justifies protection for acts of sharing information which was previously private and which a person has no duty to share. Julie Inness’s intimacy account justifies protection through appeal to the emotional context that accompanies the relationship between an agent and the act/item/information. This emotional context involves having a loving, caring, or valuing relationship. The intimacy account of artists’ moral rights draws from both to create a justification for protecting moral rights based on the idea that artist reveal information and ideas that could have been kept private and do so with the proper accompanying emotional context.
In Chapter Two, I identify the type and scope of artists’ moral rights protected by the intimacy account. I apply the intimacy account developed in Chapter One to the traditional rights covered under the umbrella of artists’ moral rights: the right of disclosure, the right of attribution, the right of withdrawal, and the right of integrity. I provide examples and arguments to demonstrate the connections between intimacy and all four traditional moral rights. The Chapter concludes with an extended case study of destruction of graffiti artworks at the well-known site 5 Pointz and a brief discussion of a case involving the posthumous retitling of a work by artist Emily Carr.
In Chapter Three, I explore the current state of moral rights protections in the US legal context, offer a critique of the current state of these rights, and offer an initial proposal for what I believe is an improved approach to protecting artists’ moral rights. The chapter serves as an initial scholarly response to 2019 Copyright Office Report on the state of moral rights protections. The chapter moves through the current patchwork of protections for moral rights. In doing so, I identify some central themes: for instance, the fact that laws tend to extend to moral rights protections unintentionally and as a result fail to offer protection when tensions occur between moral rights and the stated intent of the law. I conclude by presenting a guide towards stronger moral rights protections. The explicit adoption of a federal statute aimed at protecting artists’ moral rights, with acknowledgement of the intimacy-based justifications for these protections, could guide courts towards more accurately enforcing the protection of rights
Geographies of lithium in Bolivia: conflicts over conditions
Get PDFLithium is a metal with a rising global demand due to its applicability in batteries for electric vehicles and renewable energy storage. Bolivia holds the biggest lithium reserves in the world but has not been able to industrialize lithium to be considered a major exporter to the global market. Instead, the extraction and industrialization of lithium has been full of conflicts between government actors and some social groups of Potosí dissatisfied with their resources management decisions.
This thesis examines how social movements and the Bolivian government have had conflicts and disputes around lithium since its discovery in the 1970s, and how these conflicts have shaped the contemporary lithium scenario of the lithium industry in Bolivia. I conducted a historical overview based mainly on secondary resources, to understand the roots of Potosí’s social movements demands. I used a thematic analysis over three case studies of conflicts over lithium to identify similarities between events and understand what the main themes around these conflicts are. I collected primary information from Bolivian Legal Regulations about lithium, institutional documents of the Bolivian government and its ministries, and three archives of Bolivian digital newspapers: Los Tiempos, El Diario and La Razón.
This study contributes to the socio-ecological knowledge over conflicts on lithium extraction. The key finding was that the struggles over lithium in Bolivia have unfolded due to the battle for control and participation in the process and not to the industrialization of the natural resource itself. Secondly, the collective memory of natural resource extraction, built since colonial times, has shaped the motivations, and demands of social movements from the region of Potosí
Aerial photo index, McIntosh County, OK. Section 8 of 8
No full textAerial photograph index (photomosaic), McIntosh Co. OKLA -AWJ- MAP 8 of
Aerial photo index, Muskogee County, OK. Section 13 of 15
No full textAerial photograph index (photomosaic), Muskogee Co. Okla. -AU- MAP 13 of 1
UnBranding: Disenfranchising Terrorism and Disenchanting Terrorists
Get PDFThis research addresses the perceived problem that past and current VEO engagement programs have been ineffective in achieving their original goals. It introduces a new approach to disenchant extremism and disenfranchise VEOs – Unbranding, defined here as the application of coordinated and synchronized powers to transform a name brand into a generic brand. A study of the history of the Irish Republican Army (IRA) and Islamic State (IS) illustrates the premise that the brand is the center of gravity of the organization. A potential explanation of how and when VEOs expand is tentatively explored. Regarded by the author as a robust pilot study, an empirical study demonstrates how a stakeholder’s personality can be a predictor of generic or name brand choices. For this study, a statistical model was specified to explain the correlation with stakeholder personality and generic or name brand selection. Regression and Path Analysis explored the relationships between the latent variables Intensity, Activity, Personality, and Resonance. Structural Equation Modelling (SEM) was used to identify the strength of relationships between structural components in the model. The study illustrates that stakeholders with a lower personality score may demonstrate low resonance and may not be moved to action for a VEO name brand. As such, a reduction in brand value and equity, as well as the resulting drop in categorical performance and standing, will weaken the organization’s ability to recruit or generate stakeholders who are willing to increase personal risk for the sake of the organization
Characterizing two enzymes involved in carbon utilization and energy production in Syntrophus aciditrophicus strain SB.
No full textMethane is both an alternative energy source and a potent greenhouse gas. Biomethanation relies on the metabolic syntrophy between fermenting bacteria, syntrophs, and methanogenic archaea – where large organic molecules are metabolized to methane in a microbial assembly line. In most cases, the metabolism of syntrophs is the rate-limiting step – so when their metabolism is hindered, methanogenesis is also hindered. In this dissertation, two enzymes from the metabolic pathway of Syntrophus aciditrophicus strain SB, a model syntroph, are investigated to understand how the organism efficiently utilizes carbon and produces energy. Previous studies have found that S. aciditrophicus strain SB utilizes a novel mechanism to produce ATP with an AMP-forming acetyl-CoA synthetase (SaAcs1). In other organisms, Acs-family enzymes typically function in the AMP-forming direction rather than the ATP-forming direction. S. aciditrophicus strain SB maintains high intracellular levels of AMP and PPi, which makes ATP production by SaAcs1 favorable. The objective of this dissertation was to further investigate SaAcs1 on a structural level using X-ray crystallography and expand on previous functional studies by incorporating site-directed mutagenesis to explore the role of key amino acids in SaAcs1 activity. The structure of SaAcs1 bound to acetyl-AMP in the adenylation conformation was resolved at 3.24 Å resolution. Several structural differences were observed when compared to other previously described Acs-family proteins. Specifically, lysine 619 in the ATP/acetyl-AMP/AMP-binding site protrudes further into the substrate pocket when compared to other Acs structures. Additionally, in other Acs-family structures, there are two highly conserved charged amino acid residues at the entrance of the CoA tunnel where the overall positions of these residues do not change regardless of the presence of CoA or the conformation of the enzyme. Whereas in SaAcs1, the position of these residues (arginine 191 and 194) is shifted. These structural differences may contribute to the operation of SaAcs1 in the ATP-forming direction in S. aciditrophicus – especially when combined with the higher intracellular concentration of pyrophosphate and AMP. Alanine substitutions at key residues that may interact with ATP, acetyl-AMP, and AMP (Ser273, Gly395, Thr420, Trp421, Trp422, and Arg536) were introduced into cloned Sa acs1 using site-directed mutagenesis. Substitutions at Ser273 and Arg536 resulted in no acetyl-CoA-forming activity, and substitutions at Gly395, Thr420, and Trp421 resulted in lowered acetyl-CoA-forming activities. As for the acetate-forming activity, alanine substitution at Ser273 resulted in no activity whereas substitutions at Gly395, Thr420, Trp421, and Arg536 resulted in lowered activities when compared to wildtype SaAcs1. The lowered acetyl-CoA- and acetate-forming activities of all variants suggest that these residues may play an important part in the enzymatic reactions of SaAcs1. The structural and enzymatic findings of SaAcs1 provide greater insight into how S. aciditrophicus strain SB persists given the constrained thermodynamics. Furthermore, the structure of SaAcs1 in the adenylation conformation is a contribution to the study of the Acs protein family. There are just a few Acs structures in the adenylation conformation in the Protein Data Bank. Medically-relevant microbes often use Acs enzymes in their fatty acid synthesis – therefore, Acs enzymes have been prime targets for therapeutics so additional knowledge of this family of proteins has the potential to aid in therapeutic design. Previous studies have found that the degradation and formation of benzoate and cyclohexane-1-carboxylate in S. aciditrophicus strain SB share the same suite of enzymes. Both benzoate and cyclohexane-1-carboxylate have been shown to be converted by BamR, BamQ, and BamA to 3-hydroxypimelyl-CoA. From there, 3-hydroxypimeloyl-CoA dehydrogenase (SaHcd1) has been proposed to convert 3-hydroxypimelyl-CoA to 3-oxopimeyl-CoA. In this dissertation, the structure of a putative SaHcd1 was determined to 2.30 Å and contained six β-sheets, eight α-helices, and three unresolved loops. Further investigation of the enzymatic activity is needed to confirm that the heterologously expressed enzyme is capable of the specific substrate conversion, converting 3-hydroxypimelyl-CoA to 3-oxopimeyl-CoA and vice versa. A previous genomic study does show that the gene of the putative SaHcd1 is expressed at high levels in S. aciditrophicus strain SB, providing further evidence that this enzyme is expressed and used in the pathway. Overall, the structure of SaHcd1 provides more information into the enzymes that participate in the syntrophic conversion of fatty and aromatic acids into the precursors for methanogenic metabolism. Overall, the primary objective of this dissertation is to provide additional information on how S. aciditrophicus strain SB generates ATP and metabolizes carbon sources. Although the application of anaerobic digestion for production is not a novel application and various research has been conducted on metabolic syntrophy in anaerobic environments, there are still unknowns in syntrophic metabolism and energy conservation. This dissertation focuses on two parts of a complex biological system: two enzymes from a model syntrophic organism that is part of the microbial conversion of natural polymers to methane. Producing methane through anaerobic digestion to serve as an alternative to fossil fuels and managing methane emissions are important long-term goals. Therefore, to be successful in the application of anaerobic digestion, a better understanding of syntrophic metabolism is crucial to the larger picture and goal