Although hypertension has received a great deal of attention from many investigators in recent years, and although several different experimental approaches have been made to the problem, the etiology of most forms of the disease in man remain uncertain. The unusual problems facing the experimental worker in this field have had a lot to do with the slow progress that has been made. One of these problems consists of the inability, up to the present, of the worker to induce in an experimental animal, a state that is truly representative of hypertension in man. However, in spite of this and other obstacles, some progress has been made. / Science, Faculty of / Botany, Department of / Zoology, Department of / Graduate

No description available.

The idea of creating a material or barrier that attenuates shock and blast waves has long been investigated. Considerable work has been performed on the interactions of shock and blast waves with various materials. The application of permeable solids, porous materials and textiles for the attenuation and reflection of destructive shock waves have been studied extensively. The studies presented herein examine the interaction of shock waves and porous plates in order to ameliorate the hazardous effects of these waves particularly in ducts or channels leading to protected areas or objects. A number of tests were performed in an automated shock tube to determine the effects that a series of directional porous plates had on the initial peak pressure and impulse amelioration experienced by the end wall. Mild steel test specimens, ranging in porosity values from 6.6 % to 41.1 %, were mounted two at a time in the test section of the shock tube. Each plate had directional properties and since four plates were used in the study, a total of forty eight plate configurations were tested. Six pressure transducers were located along the side of the test section and two pressure transducers were located in the end wall of the shock tube in order to measure initial peak pressure and impulse amelioration values experienced by the end wall and to identify the wave interactions involved in the amelioration process. Schlieren photographs were also taken in order to investigate these wave interactions. Tests were run at three different Mach numbers viz. 1.23, 1.35 and 1.42. The separation distances between the plate specimens were varied between 30 mm and 60 mm; however the distance between the downstream plate and the end wall was kept constant at 140mm for all tests. It was found that significant initial peak pressure and impulse amelioration was achievable. The Back & Back plate arrangement produced the greatest initial peak pressure and impulse amelioration with averages values of 73.7 % and 20.45 % respectively. Both the initial peak pressure and impulse amelioration values were found to be dependant on the plate combination porosity. As the porosity of the combination increased, the amelioration values decreased. Complementary plate combinations produced differing results as different wave interactions occur when plate positions were interchanged. The porosity of the combined plates were found to have an overriding influence on the end wall initial peak pressure and impulse amelioration values when compared to the effect that plate arrangement (i.e. geometrical influences) had. For all tests performed in this study, the time period used for the integration of the end wall pressure traces was 9 250 μs. As an acceptable closing time for a blast valve in a shelter’s ventilation system is approximately 4 000 μs, the impulse amelioration values for certain plate combinations were recalculated. It was found that using this time period greater impulse amelioration values were produced as the rate of pressure rise, dp/dt, was initially lower at the beginning of the end wall pressure trace. Therefore, the lowest impulse amelioration value (7.9 %) achieved in this study, would produce significant impulse amelioration (20.3 %) if it were to be used in a shelter’s ventilation system. Impulse amelioration values were found to increase as the separation distance between v plates were increased. The average impulse amelioration value was found to increase approximately 1 % for a 15mm increase in the distance between plates. The amplitude of the entire end wall pressure trace was found to increase as the incident Mach number was increased. This resulted in greater initial peak pressure and impulse experienced by the end wall. The significant attenuation of the incident shock wave obtained during this study is attributed to the system of multiple reflected and transmitted waves that are produced by the presence of the plate specimens in series. This increases the frequency of shock wave and barrier interactions, when compared to just using a single barrier, creating regions of highly unsteady flow, especially in the air space between the plate specimens. Furthermore, the presence of the series of plates also allows for wave resonance to occur which may further attenuate the strength of the incident shock wave. It is suggested that future studies include numerical techniques in order to further investigate the complex wave processes that occur upon interaction with the plate specimens and confirm the major loss mechanisms of the system.

This dissertation examines the era of slavery amelioration while situating the significance of this project to reform slavery within the longer history of the British Empire. While scholars of British slavery have long debated the causes of both the abolition of the slave trade (1807) and the abolition of slavery (1833), they have overlooked the ways that both abolitionists and politicians attempted to "reform" slavery - extending both baseline protections and a civilizing mission toward slaves - as a prelude toward broader emancipation. This attempted amelioration of slavery influenced both the timing and form that emancipation took. By focusing on the island where metropolitan officials first attempted to exert an ameliorative agenda, this dissertation uncovers the forgotten influence of Spanish laws and practices on British abolitionism. Trinidad was captured from Spain in 1797 during the heyday of abolitionist agitation, during an era when Spanish slave codes were gaining newfound attention among British reformers for their reputed benevolence. Despite local planter opposition, metropolitan officials elected to retain the island's Spanish legal structure following the Peace of Amiens. The Trinidad template for amelioration would be framed around the island's Spanish laws, notably the office of Protector of Slaves. This individual was imagined as an intermediary between master and slave, metropole and colony, epitomizing an attempt to infuse the slave regime with a modicum of imperial regulation. The ideas behind amelioration survived the abolition of slavery. After Caribbean slavery was abolished between 1833 and 1838, the reforms that had been attempted in Trinidad and elsewhere over the previous decades came to inform the regulation of labor relationships, particularly immigrant labor, following in its wake. The process of negotiating reform - of slavery, indentured labor, and relations with indigenous peoples - had taught Colonial Office officials to distrust the instincts and activities of white colonial subjects. The Protector model proliferated in contexts of continued distrust during an era when metropolitan officials remained reluctant to exert more direct authority than necessary. This model would break down only in the wake of repeated failure. Until then, metropolitan officials hoped that local watchdogs would "protect" nonwhite and laboring subjects from abuse. / History

Dans cette thèse, nous nous intéressons à la conception et à la visualisation de cartes géographiques personnalisées en passant par des étapes d'évaluation et d'amélioration automatiques de ces cartes.Dans la plupart des outils cartographiques récents (comme le GeoPortail ou Google Maps) il est possible pour l'utilisateur de construire lui-même une carte adaptée à ses besoins à partir des couches de données pouvant provenir de sources hétérogènes. Cependant, la manipulation et l'édition de cartes par des utilisateurs non-experts peuvent engendrer des erreurs de représentation qui entravent la compréhension de cette carte par ses lecteurs.Notre recherche concerne donc l'amélioration de la représentation de cartes créées par des utilisateurs non-experts. Etant donné que la lisibilité d'une carte passe par la visibilité des objets qui la composent, dans ce travail nous proposons un modèle qui évalue la visibilité de ces objets cartographiques en se fondant sur un système de cinq indicateurs de visibilité dont les valeurs varient entre 0 et 1. Ce modèle prévoit ensuite quatre méthodes de modification de la symbolisation des objets cartographiques, qui seront utilisées afin d'améliorer leur visibilité. Entre l'étape d'évaluation et celle de l'amélioration de la visibilité de ces objets, une phase d'analyse est mise en place dans le but de décider si une amélioration de la symbolisation des objets cartographiques est nécessaire, et si oui, choisir lesquelles parmi ces modifications pourront être réalisées.Ce modèle prendra comme entrée une carte géographique sous la forme (1) d'un ensemble de couches composées chacune d'objets cartographiques, (2) et de la légende utilisée pour la symbolisation de ces objets cartographiques. Il donnera en sortie (1) un ensemble de fichiers xml qui contiennent les valeurs calculés des indicateurs de visibilité, (2) une carte finale avec une nouvelle symbolisation qui améliore la valeur des indicateurs de visibilité. Ce processus offre alors aux lecteurs une carte plus lisible.Ce travail est ensuite conclu par deux tests qui valident (1) les hypothèses de base, (2) la correspondance effective entre les valeurs des indicateurs et le ressenti réel des lecteurs de cartes, et qui tentent (3) de dégager des seuils de visibilité qui seront utilisés dans le but de corriger et affiner ultérieurement les algorithmes écrits lors de cette thèse / In this thesis, we focus on the design and visualization of custom geographic maps by executing different stages of automatic evaluation and improvement of these maps.In the most recent mapping tools (such as Google Maps or GeoPortail) it is possible for the user to build himself a map that suits his needs using different layers of data which can come from several sources. However, the manipulation and edition of maps by non-experts can cause errors in the representation that affects the understanding of this map by its readers.That's why our research focus on improving the representation of maps created by non-expert users. Since the readability of a map depends on the visibility of objects that compose this map, in this work we propose a model which assesses the visibility of cartographic objects based on a system of five indicators of visibility (values between 0 and 1). This model then provides four methods for modifying the objects symbolization of this map, which will be used to improve their visibility. Between the evaluation and the improvement of the visibility of these objects, an analysis step is performed in order to decide whether an improvement in the symbolization is required, and if so, which of these four methods should be executed.This model takes as input a map in the form of (1) a set of layers each consisting of cartographic objects, (2) and the legend used to represent these cartographic objects. It will generate as an output (1) a set of XML files that contain the values calculated by the indicators of visibility, (2) a final map with a new representation that improve the value of these indicators of visibility. This process then provides readers with a more readable map.This work is then concluded by two tests that validate (1) our basic assumptions, (2) the actual correspondence between the indicator values and the real feel of the map readers, and finally trying (3) to determine visibility thresholds that can be used later in order to correct and refine the algorithms that are proposed in this thesis

Scar: A lingering sign of damage or injury, either mental or physical. Technological advancement scars the landscape. It has been our practice to ignore, or worse, hide these marks that have been made as society continues to advance. Industries past left us relics and ruins of bygone eras of promise and production. The time we live in has recognized the untenable failures of past generations, however there are methods of industry that continue to injure the landscape. We will leave our scars. In this time we must rethink the scar, define it, and recognize its beauty. The first step of reclamation is acquiring awareness of where the scar came from. Whether it is an injury, an accident, or a natural disaster, some traumatic event caused lasting damage. Traumatic events whether natural - hurricanes, floods and earthquakes - or manmade - wars, genocide and assaults - can cause both physical and emotional scars. Human tissues can repair themselves leaving scars, but there are also the scars of repair. Even technological advancements in medicine cannot eliminate the scar. Scarring is the natural healing process, yet we view them as unnatural. Once recognized, we must accept the scar so that we do not destroy it. We must accept the traumatic cause/effect relationships, and be conscious of the healing process. The scar must be appreciated: the time that it takes to make it, the time that it takes to heal, the history it can teach, and the story that it can tell. To hide it would only be an injustice to those who came before us and to those yet to come. With acceptance a scar’s beauty can be seen. Every new era of technology, every successive generation, leaves a scar. The opportunity to aid the greatest healer – time – is now. Every scar tells a story. Reclamation: A restoration, as to productivity, usefulness, or morality.

Physical exercise offers a highly effective health-endowering activity as has been evidence using rodent models of Parkinson’s disease (PD). It is a particularly useful intervention in individuals employed in sedentary occupations or afflicted by a neurodegenerative disorder, such as PD. The several links between exercise and quality-of-life, disorder progression and staging, risk factors and symptoms-biomarkers in PD all endower a promise for improved prognosis. Nutrition provides a strong determinant for disorder vulnerability and prognosis with fish oils and vegetables with a mediterranean diet offering both protection and resistance. Three factors determining the effects of exercise on disorder severity of patients may be presented: (i) Exercise effects upon motor impairment, gait, posture and balance, (ii) Exercise reduction of oxidative stress, stimulation of mitochondrial biogenesis and up-regulation of autophagy, and (iii) Exercise stimulation of dopamine (DA) neurochemistry and trophic factors. Running-wheel performance, as measured by distance run by individual mice from different treatment groups, was related to DA-integrity, indexed by striatal DA levels. Finally, both nutrition and exercise may facilitate positive epigenetic outcomes, such as lowering the dosage of L-Dopa required for a therapeutic effect.

Two greenhouse experiments were conducted to determine the amelioration effect of Ca salts (CaS04 and CaC12 ) on the growth of snapbeans (Phaseolus vulgaris L.) under sodium stress and to determine the effect of ion speciation on the uptake of Ca, Na, S04, and Cl by snapbeans. In Experiment 1, the seeds were grown in styrofoam pots, with a growing medium of sand and vermiculite at a volume ratio of 3:1. The treatment solutions were 0 (Hoagland's solution), 20, 40, 60, and 80 mmolc/L NaCl or Na2S04. Statistical analysis (ANOVA) showed that NaCl treatments depressed the growth of snapbeans more than corresponding Na 2S04 treatments. Also NaCl treatments increased the uptake of Na and Ca as compared to Na2S04treatments. Sodium uptake appeared to be related to the concentrations of complex species rather than to free Na ion, whereas Ca uptake strongly correlated with free Ca2+ concentration. In Experiment 2, the seeds were grown in a sand growing medium. The treatment solutions were 0 (Hoagland's solution), 15, 30, 45, and 60 mmolc/L NaCl or Na2S04 , combined with CaSO4 • 2H20 or CaCl2 • 2H20 at concentrations of 15 or 30 mmolc/L . In addition, one replicate was planted in PVC cells (with electrodes) in order to monitor the electrical conductivity of the media using the four probe. The results showed that addition of CaS04 to NaCl or Na2S04 was associated with a better amelioration of Na stress than CaCl2 • Also the presence of CaS04 , with NaCl or Na2S04 , decreased the uptake of Ca and Na ions relative to CaCl2 treatment. Ion speciation data suggested that Na complexation was more important than free ion concentration in affecting Na uptake by the plant, whereas Ca, S04 , and Cl uptake were correlated to free ion concentrations. With respect to EC, determinations, the four probe was used to monitor salinity during the whole experiment period. Ion speciation data showed that Na2S04 treatments had a lower EC than NaCl at the same molar concentration levels. Also, CaS04 treatments, regardless of the Na salt, had lower EC values than CaCl2 treatments of equal concentration.

Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Substance abuse is an imminent danger on the health of both substance users and nonusers. In general, abuse of psychoactive substances is associated with high risk behaviour, mortality and morbidity. The drug use cycle involves inextricably intertwined variants such as production, trading and usage of both licit and illicit addictive substances. The dynamics of substance use involve initiation, addiction, rehabilitation/treatment and quitting/ recovery. In response to supply and abuse of monster drugs, control strategies such as law enforcement and rehabilitation have been stepped up to reduce access to drugs by targeting drug kingpins and harm reduction respectively. In this thesis, we model the factors affecting the prevalence of substance abuse, the effect of drug lords on the prevalence of substance abuse, and the impact of substance abuse on the prevalence of HIV/AIDS. We formulate mathematical models based on systems of autonomous differential equations describing the dynamics of the sub- populations involved in the drug using cycle. We examine the effects of amelioration, rehabilitation/treatment and re- initiation on the prevalence of substance abuse. Our results suggest that, recruitment into rehabilitation and amelioration in the presence of quitting for light users reduce the prevalence of substance abuse; re-initiation and amelioration without quitting for light users increase the prevalence of substance abuse. Our assessment of the impact of drug lords and the effect of law enforcement on drug epidemics shows that, the presence of drug lords seriously constraints the efforts to reduce substance abuse since they increase access to drugs. However, law enforcement if stepped up in response to the population of drug lords, greatly reduces the prevalence of substance abuse. Given the associated influence of drugs on high risky behaviour, as a cofactor for sexually transmitted infections, we assess the influence of substance abuse on the prevalence of Human Immunodeficiency Virus (HIV). Our results show that dissemination of information regarding HIV and drug use reduces HIV prevalence whereas, there is faster spread of the epidemic and high prevalence with increased sexual contact. / AFRIKAANSE OPSOMMING: Dwelmmisbruik is ’n dreigende gevaar vir die gesondheid van beide dwelm gebruikers en nie-gebruikers. In die algemeen, word die misbruik van psigoaktiewe dwelms verbind met hoë risiko gedrag, mortaliteit en morbiditeit. Die dwelmgebruikskringloop behels onlosmaaklik vervlegde variante soos vervaardiging, handel en gebruik van beide wettige en onwettige verslawende middels. Die dinamika van dwelms behels aanvang, verslawing, rehabilitasie/ behandeling en staking/herstel. In reaksie op die misbruik en verskaffing van monster dwelms, is beheer strategieë soos wetstoepassing en rehabilitasie verskerp, om die toegang tot dwelms te verminder, deur onderskeidelik te fokus op dwelmspilfigure en skadebeperking. Die belangrikste doel van hierdie verhandeling is om die faktore te modelleer wat die voorkoms van dwelmmisbruik beïnvloed, die uitwerking van dwelmbase op die voorkoms van dwelmmisbruik, en die trefkrag van dwelmmisbruik op die voorkoms van MIV / VIGS. Ons formuleer wiskundige modelle gegrond op stelsels van outonome differensiaalvergelykings, wat die dinamika beskryf van die sub-bevolkinge wat in die dwelmgebruikskringloop betrokke is. Ons ondersoek die effekte van verbetering, rehabilitasie/behandeling en heraanvang op die voorkoms van dwelmmisbruik. Ons resultate dui dat, werwing tot rehabilitasie en verbetering in die teenwoordigheid van stakende tydelike verbruikers, die voorkoms van dwelmmisbruik verminder; heraanvang en verbetering sonder dat tydelike verbruikers staak, verhoog die voorkoms van dwelmmisbruik. Ons raming van die invloed van dwelmbase en die uitwerking van wetstoepassing op dwelm-epidemies toon dat, die teenwoordigheid van dwelmbase belemmer grotendeels die pogings om dwelmmisbruik te verminder, aangesien hulle toegang tot dwelms verhoog. Nietemin, as die wetstoepassing verskerp word in reaksie op die dwelmbaasbevolking, word die voorkoms van dwelmmisbruik aansienlik verminder. Gegewe die gepaardgaande invloed van dwelms op hoë risiko gedrag as ’n kofaktor vir seksueel oordraagbare infeksies, beraam ons die invloed van dwelmmisbruik op die voorkoms van die Menslike Immunogebreksvirus (MIV). Ons resultate toon dat inligtingverspreiding rakende MIV en dwelmgebruik, MIV-voorkoms verlaag, terwyl daar ’n vinniger verspreiding van die epidemie en hoë voorkoms is, met verhoogde seksuele kontak.

<p>So far little research has been done on the term bitch exclusively. The aim of this essay is to find a pattern of teenagers’ uses of the word bitch in various contexts and in different grammatical forms. A further question is whether bitch can be considered a swearword or not.</p><p>The investigation was carried out by using two different corpora which is COLT (The Bergen Corpus of London Teenage Language) and Webcorp as the primary sources out of which concordance lines were extracted. These were in turn categorized into different word classes and analyzed in detail. The results show that there were several word classes in which bitch appeared such as noun, verb and adjective and the most common word class is nouns. The results also show that teenagers mainly use the term as a swearword with which they address their peers. In conclusion even though the term bitch did not originally belong to taboo language, however, due to the fact that the word has developed a more negative meaning it can be seen a swearword.</p>