The chosen project is a response to the need of human beings to connect with nature. It demonstrates how landscape architecture can help to develop recreational open space that improves the natural systems within the city and ultimately enhance human and ecological wellbeing. The proposed solution will investigate the relationship between population growth, urbanisation, open space requirements and how to fulfil the need to connect with an ecologically sound environment in order to create responsive landscape architecture. The aim is to steer away from a monofunctional landscape but to design ecologically functional spaces that will address the public need and be the intermediate biophysical connection. Open space typologies are investigated in relation to their functionality within the urban environment. Spatial requirements according to the CSIR guidelines are used in order to determine whether existing open spaces provision is adequate. The scales of investigation range from microscopic research to the implementation of the design. Recreational facilities should be included according to the need thereof. The proposed facility is thus composed out of various different programmes, each with its own specific requirements. The composition of the open spaces is according to the CSIR’s settlement development requirements, proposals done by Encha Properties and MDC (Pty) Ltd. A proposal by Tshwane identifies open spaces in general and to complete the intermediate biophysical connection the design propose a general programme assigned to other unidentified adjacent spaces along the Apies River. The spaces can broadly be divided into recreational open space, educational recreation, sports recreation, cultural recreation, and some mixed use spaces. The Apies River serves as connector between spaces, as an opportunity to create a green corridor along which people, plants and animals can migrate / Dissertation (ML(Prof))--University of Pretoria, 2015. / Architecture / ML(Prof) / Unrestricted

Skeletal muscle regeneration is dependent upon the influences of intrinsic and extrinsic factors that stimulate satellite cells. Regenerating proteins are upregulated at the onset of trauma or inflammation in the pancreas, gastrointestinal tract, liver, neural cells and other tissues. Studies have shown that Reg proteins have a mitogenic, anti-apoptotic and anti-inflammatory function in damaged tissues and is necessary for normal progression of regeneration. As skeletal muscle is also able to regenerate itself at a rapid rate, it seems highly likely that Reg proteins function to promote myogenesis in skeletal muscle regeneration. Therefore, the goal of our research was to characterize the expression of the Reg proteins and receptor in regenerating skeletal muscle and satellite cells, investigate the effect of exogenous Reg protein on myogenesis, and to examine direct Reg protein effect on satellite cell activity. To determine whether Reg proteins participate in skeletal muscle regeneration, mice were injected with marcaine in their tibialis anterior muscles to induce skeletal muscle damage. The gene expression analysis of undamaged and marcaine-damaged tibialis anterior muscles and mice satellite cells showed that Reg I, II, IIIα, IIIγ, IV and EXTL3 genes are present during skeletal muscle regeneration and satellite cells significantly express Reg I, IIIα, IIIγ and EXTL3. As Reg I and IIIα are most prevalent in vivo and in vitro respectively, we advocate these isoforms as the predominant candidates in skeletal muscle regeneration. To determine the effect of exogenous Reg protein on myogenesis, we performed gene expression and muscle morphometry analysis of Reg IIIα or PBS injected tibialis anterior muscles. Interestingly, our results indicate that the addition of Reg IIIα to damaged muscles inhibited myogenesis. To determine the direct effect of Reg protein on myogenic stem cell activity, Reg proteins were added to mice satellite cells and C2C12 cells. Results from these studies were inconclusive due to the failure of known positive and negative controls. Overall, our studies suggest that Reg proteins contribute to skeletal muscle regeneration; however, as an overabundance of Reg IIIα in regenerating tissues may have inhibited myogenesis, it is imperative that other isoforms or lower concentrations be investigated.

Management and restoration of black oak dominated sand savannas often rely on historic vegetative descriptions (settler accounts, surveyor notes, aerial photographs). It is commonly assumed that fire alone maintains savanna structure and composition, however little information is known about the specific fire frequency needed to maintain these systems. The objective of this study was to quantify and correlate characteristics of stand structure with fire history of the Kankakee Sands savannas in northeastern Illinois. Fire history chronologies were determined through dendrochronological methods from 289 dated fire scars identified on 58 black oak (Quercus velutina) trees located throughout four wooded sites. Tree and woody structure was characterized in 30 circular plots (0.04 hectares) in three sites and 26 circular plots in one site that were placed at 25-meter intervals along randomly established permanent line transects in the summer of 2007. The structure analysis consisted of the development of tree age-size relationships among presently dominant and suppressed trees in relation to fire history. Variations in tree and woody structure were strongly related to fire dynamics among the four study sites. Specifically, components such as tree density (n = 114; r = 0.46; P < 0.0001), basal area (n = 114; r = 0.35; P < 0.0001), and total woody stem density (n = 114; r = 0.42; P < 0.0001) all increased as a function of fire-free interval. In addition, sites with shorter fire-free intervals were associated with a higher percentage of hollow tree boles (n = 104 r = -0.31 P < 0.0015) and visible fire scar wounds (n = 104 r = -0.43334 P < 0.0001). While the results of this study suggest fire had a significant role in structuring these four wooded sites, the data also indicated other historic disturbances coupled with individual site characteristics may be integral components in structuring these dynamic systems. For instance, fire-free intervals less than two years maintained conditions of openness, as was referenced to 1939 historic aerial photographs, but eliminated potential future canopy trees. Under these conditions, a dramatic shift in community structure toward prairie vegetation is likely, as no smaller trees were present to assume canopy dominance. Fire-free intervals greater than two years were associated with transition to closed canopy forests. Therefore, management considerations pertaining to fire with the addition of other historic disturbances, including grazing and or selective cutting, are proposed to balance historic canopy openness and promote regeneration of characteristic savanna species.

Distributed storage systems provide fast and reliable access to data by intro- ducing redundancy for stored les. The most common approach of adding re- dundant information is by repetition and erasure codes. Two main processes in a distributed storage system are reconstruction of original le and regenerat- ing a new node. These two processes require bandwidth, which are termed as reconstruction-bandwidth and repair-bandwidth. The current literature treat- s these two processes separately. That is, there are methods to reduce the reconstructing bandwidth without considering the repair-bandwidth, and also there are methods to reduce the repair-bandwidth. We study these two pro- cesses together and try to jointly minimize the reconstruction-bandwidth and repair-bandwidth. We observe a method that has the minimum reconstruction- bandwidth might have large amount of repair-bandwidth and vice versa. We propose codes which minimizes the sum of the repair-bandwidth and reconstruction- bandwidth. The main contribution of this thesis is nding an value of repair locality r (number of nodes connected during node repair) and devising two coding meth- ods in which total bandwidth approximates to be half reduced compared with MSR and MBR when k ! 1 under the condition that 1 6 r 6 k.

No description available.

No description available.

Error-control codes, which are being extensively used in communication systems, have found themselves very useful in data storage as well during the past decade. This thesis deals with two types of codes for data storage, one pertaining to the issue of privacy and the other to reliability. In many scenarios, user accessing some critical data from a server would not want the server to learn the identity of data retrieved. This problem, called Private Information Retrieval (PIR) was rst formally introduced by Chor et al and they gave protocols for PIR in the case where multiple copies of the same data is stored in non-communicating servers. The PIR protocols that came up later also followed this replication model. The problem with data replication is the high storage overhead involved, which will lead to large storage costs. Later, Fazeli, Vardy and Yaakobi, came up with the notion of PIR code that enables information-theoretic PIR with low storage overhead. In the rst part of this thesis, construction of PIR codes for certain parameter values is presented. These constructions are based on a variant of conventional Reed-Muller (RM) codes called binary Projective Reed-Muller (PRM) codes. A lower bound on block length of systematic PIR codes is derived and the PRM based PIR codes are shown to be optimal with respect to this bound in some special cases. The codes constructed here have smaller block lengths than the short block length PIR codes known in the literature. The generalized Hamming weights of binary PRM codes are also studied. Another work described here is the implementation and evaluation of an erasure code called Coupled Layer (CL) code in Ceph distributed storage system. Erasure codes are used in distributed storage to ensure reliability. An additional desirable feature required for codes used in this setting is the ability to handle node repair efficiently. The Minimum Storage Regenerating (MSR) version of CL code downloads optimal amount of data from other nodes during repair of a failed node and even disk reads during this process is optimum, for that storage overhead. The CL-Near-MSR code, which is a variant of CL-MSR, can efficiently handle a restricted set of multiple node failures also. Four example CL codes were evaluated using a 26 node Amazon cluster and performance metrics like network bandwidth, disk read and repair time were measured. Repair time reduction of the order of 3 was observed for one of those codes, in comparison with Reed Solomon code having same parameters. To the best of our knowledge, such large gains in repair performance have never been demonstrated before.

This thesis deals with the problem of code design in the setting of distributed storage systems consisting of multiple storage nodes, storing many different data les. A primary goal in such systems is the efficient repair of a failed node. Regenerating codes and codes with locality are two classes of coding schemes that have recently been proposed in literature to address this goal. While regenerating codes aim to minimize the amount of data-download needed to carry out node repair, codes with locality seek to minimize the number of nodes accessed during node repair. Our focus here is on linear codes with locality, which is a concept originally introduced by Gopalan et al. in the context of recovering from a single node failure. A code-symbol of a linear code C is said to have locality r, if it can be recovered via a linear combination of r other code-symbols of C. The code C is said to have (i) information-symbol locality r, if all of its message symbols have locality r, and (ii) all-symbol locality r, if all the code-symbols have locality r. We make the following three contributions to the area of codes with locality. Firstly, we extend the notion of locality, in two directions, so as to permit local recovery even in the presence of multiple node failures. In the first direction, we consider codes with \local error correction" in which a code-symbol is protected by a local-error-correcting code having local-minimum-distance 3, and thus allowing local recovery of the code-symbol even in the presence of 2 other code-symbol erasures. In the second direction, we study codes with all-symbol locality that can recover from two erasures via a sequence of two local, parity-check computations. When restricted to the case of all-symbol locality and two erasures, the second approach allows, in general, for design of codes having larger minimum distance than what is possible via the rst approach. Under both approaches, by studying the generalized Hamming weights of the dual codes, we derive tight upper bounds on their respective minimum distances. Optimal code constructions are identified under both approaches, for a class of code parameters. A few interesting corollaries result from this part of our work. Firstly, we obtain a new upper bound on the minimum distance of concatenated codes and secondly, we show how it is always possible to construct the best-possible code (having largest minimum distance) of a given dimension when the code's parity check matrix is partially specified. In a third corollary, we obtain a new upper bound for the minimum distance of codes with all-symbol locality in the single erasure case. Secondly, we introduce the notion of codes with local regeneration that seek to combine the advantages of both codes with locality as well as regenerating codes. These are vector-alphabet analogues of codes with local error correction in which the local codes themselves are regenerating codes. An upper bound on the minimum distance is derived when the constituent local codes have a certain uniform rank accumulation (URA) property. This property is possessed by both the minimum storage regenerating (MSR) and the minimum bandwidth regenerating (MBR) codes. We provide several optimal constructions of codes with local regeneration, where the local codes are either the MSR or the MBR codes. The discussion here is also extended to the case of general vector-linear codes with locality, in which the local codes do not necessarily have the URA property. Finally, we evaluate the efficacy of two specific coding solutions, both possessing an inherent double replication of data, in a practical distributed storage setting known as Hadoop. Hadoop is an open-source platform dealing with distributed storage of data in which the primary aim is to perform distributed computation on the stored data via a paradigm known as Map Reduce. Our evaluation shows that while these codes have efficient repair properties, their vector-alphabet-nature can negatively a affect Map Reduce performance, if they are implemented under the current Hadoop architecture. Specifically, we see that under the current architecture, the choice of number processor cores per node and Map-task scheduling algorithm play a major role in determining their performance. The performance evaluation is carried out via a combination of simulations and actual experiments in Hadoop clusters. As a remedy to the problem, we also pro-pose a modified architecture in which one allows erasure coding across blocks belonging to different les. Under the modified architecture, the new coding solutions will not suffer from any Map Reduce performance-loss as seen in the original architecture, while retaining all of their desired repair properties

Esta dissertação teve como objetivo geral ampliar o conhecimento sobre a ecologia vegetal das matas de Restinga arenosa em substratos bem drenados no Rio Grande do Sul. Para tanto, foram realizados o estudo florístico e fitossociológico do componente arbóreo de cinco capões de Restinga e a verificação de padrões de interações mutualísticas entre aves frugívoras e as árvores, além do estudo do componente de regeneração e suas relações com o estrato arbóreo adulto. Para a amostragem da vegetação, foi usado o método de parcelas, incluindo-se todas as árvores com DAP ≥ 5cm, totalizando uma área de 1,02ha. Com estes dados, foram estimados os parâmetros usuais em fitossociologia. Em um dos capões, foi realizado também o levantamento florístico e fitossociológico das plântulas (0,05 ≤ altura < 1m) e juvenis (altura ≥ 1m, DAP < 5cm), avaliando-se as relações com o estrato arbóreo adulto, o potencial e a taxa de regeneração natural para cada espécie. Para o estudo dos mutualismos, foram feitas observações visuais e capturas de aves durante um ano. Foram estimadas a conectância do sistema mutualístico e o índice de importância das espécies. Também foi feita a rede de interações do sistema e feita a análise da variação destas interações ao longo das estações do ano. A composição florística resultou em uma riqueza total de 20 famílias e 29 espécies para os cinco capões. A densidade total arbórea teve uma média máxima de 1207 ind/ha e mínima de 747 ind/ha. Sebastiania serrata apresentou o maior valor de importância e Myrtaceae foi a família mais representada. A diversidade específica foi baixa, variando de 1,08 a 2,38 (nats). No sistema mutualístico, registraram-se 29 espécies interagindo (aves e plantas), com uma conectância de 23,9%. Turdus amaurochalinus e T. rufiventris interagiram com a maioria das espécies arbóreas e tiveram o maior índice de importância, sendo caracterizadas como as principais dispersoras em potencial. Ocotea pulchella e Myrsine spp. foram registradas com maior número de eventos de consumo de frutos, no entanto, Ficus organesis interagiu com mais espécies frugívoras, além de ter a maior importância na dieta das aves. Houve variações no número eventos de frugivoria ao longo das estações, bem como no número de espécies frugívoras e de espécies arbóreas consumidas. O componente de regeneração apresentou riqueza específica e diversidade semelhantes às do estrato arbóreo adulto, refletindo uma similaridade florística maior que 70%. A maioria das espécies (73,7%) apresentou taxa de regeneração negativa, revelando o padrão de 'J' invertido. Os resultados indicam a existência de diferenças na composição e estrutura arbórea entre os capões de Restinga, além de uma boa capacidade de regeneração para a maioria das espécies vegetais estudadas. Os dados revelam também um sistema dispersão generalista, no qual poucas espécies de aves interagem com muitas espécies arbóreas e vice-versa. / This dissertation had as broad objective the knowledge amplification about the plant ecology of sandy Restinga forests in well drained soils in Rio Grande do Sul. For that, the floristic and phytosociological study of the tree component of five Restinga woods and the verification of mutualistic interactions patterns between frugivorous birds and trees were accomplished, besides the study of the regeneration component and its relations with the adult tree stratum. For vegetation sampling, the plot method was used, including all trees with DBH ≥ 5cm, totaling an area of 1,02ha. With these data, the usual parameters in phytosociology were estimated. In one of the woods, the floristic and phytosociological survey of the seedlings (0,05 ≤ height < 1m) and juveniles (height ≥ 1m, DBH < 5cm) was also performed, evaluating the relations with the adult tree stratum, the potential and the rate of natural regeneration for each species. For the mutualisms study, visual observations and bird captures were done throughout one year. The connectance of the mutualistic system and the species importance index were estimated. The interactions system network and the variation analysis of these interactions throughout the seasons were also done. The floristic composition resulted in a total richness of 20 families and 29 species for the five woods. The total tree density had a maximum media of 1207 ind/ha and a minimum of 747 ind/ha. Sebastiania serrata presented the highest importance value and Myrtaceae was the most represented family. The specific diversity was low, varying from 1,08 to 2,38 (nats). In the mutualistic system, 29 species interacting (birds and plants) were registered, with a connectance of 23,9%. Turdus amaurochalinus and T. rufiventris interacted with most tree species and had the highest importance index, being characterized as the main potential dispersers. Ocotea pulchella and Myrsine spp. were registered with the higher number of consumption events, although, Ficus organesis interacted with more frugivorous species, besides having the higher importance in the birds diet. There were variations in the frugivory events number throughout the seasons, as well as in the number of frugivorous species and consumed tree species. The regenerating component presented specific richness and diversity similar with the adult tree stratum, reflecting a floristic similarity higher than 70%. Most species (73,7%) presented negative regeneration rates, revealing the inverted 'J' pattern. The results point to the existence of differences in the forests tree composition and structure among the Restinga woods, besides a good regeneration capacity for most plant species studied. The data also reveal a generalist dispersal system, in which few bird species interact with many tree species and vice-versa.

Esta dissertação teve como objetivo geral ampliar o conhecimento sobre a ecologia vegetal das matas de Restinga arenosa em substratos bem drenados no Rio Grande do Sul. Para tanto, foram realizados o estudo florístico e fitossociológico do componente arbóreo de cinco capões de Restinga e a verificação de padrões de interações mutualísticas entre aves frugívoras e as árvores, além do estudo do componente de regeneração e suas relações com o estrato arbóreo adulto. Para a amostragem da vegetação, foi usado o método de parcelas, incluindo-se todas as árvores com DAP ≥ 5cm, totalizando uma área de 1,02ha. Com estes dados, foram estimados os parâmetros usuais em fitossociologia. Em um dos capões, foi realizado também o levantamento florístico e fitossociológico das plântulas (0,05 ≤ altura < 1m) e juvenis (altura ≥ 1m, DAP < 5cm), avaliando-se as relações com o estrato arbóreo adulto, o potencial e a taxa de regeneração natural para cada espécie. Para o estudo dos mutualismos, foram feitas observações visuais e capturas de aves durante um ano. Foram estimadas a conectância do sistema mutualístico e o índice de importância das espécies. Também foi feita a rede de interações do sistema e feita a análise da variação destas interações ao longo das estações do ano. A composição florística resultou em uma riqueza total de 20 famílias e 29 espécies para os cinco capões. A densidade total arbórea teve uma média máxima de 1207 ind/ha e mínima de 747 ind/ha. Sebastiania serrata apresentou o maior valor de importância e Myrtaceae foi a família mais representada. A diversidade específica foi baixa, variando de 1,08 a 2,38 (nats). No sistema mutualístico, registraram-se 29 espécies interagindo (aves e plantas), com uma conectância de 23,9%. Turdus amaurochalinus e T. rufiventris interagiram com a maioria das espécies arbóreas e tiveram o maior índice de importância, sendo caracterizadas como as principais dispersoras em potencial. Ocotea pulchella e Myrsine spp. foram registradas com maior número de eventos de consumo de frutos, no entanto, Ficus organesis interagiu com mais espécies frugívoras, além de ter a maior importância na dieta das aves. Houve variações no número eventos de frugivoria ao longo das estações, bem como no número de espécies frugívoras e de espécies arbóreas consumidas. O componente de regeneração apresentou riqueza específica e diversidade semelhantes às do estrato arbóreo adulto, refletindo uma similaridade florística maior que 70%. A maioria das espécies (73,7%) apresentou taxa de regeneração negativa, revelando o padrão de 'J' invertido. Os resultados indicam a existência de diferenças na composição e estrutura arbórea entre os capões de Restinga, além de uma boa capacidade de regeneração para a maioria das espécies vegetais estudadas. Os dados revelam também um sistema dispersão generalista, no qual poucas espécies de aves interagem com muitas espécies arbóreas e vice-versa. / This dissertation had as broad objective the knowledge amplification about the plant ecology of sandy Restinga forests in well drained soils in Rio Grande do Sul. For that, the floristic and phytosociological study of the tree component of five Restinga woods and the verification of mutualistic interactions patterns between frugivorous birds and trees were accomplished, besides the study of the regeneration component and its relations with the adult tree stratum. For vegetation sampling, the plot method was used, including all trees with DBH ≥ 5cm, totaling an area of 1,02ha. With these data, the usual parameters in phytosociology were estimated. In one of the woods, the floristic and phytosociological survey of the seedlings (0,05 ≤ height < 1m) and juveniles (height ≥ 1m, DBH < 5cm) was also performed, evaluating the relations with the adult tree stratum, the potential and the rate of natural regeneration for each species. For the mutualisms study, visual observations and bird captures were done throughout one year. The connectance of the mutualistic system and the species importance index were estimated. The interactions system network and the variation analysis of these interactions throughout the seasons were also done. The floristic composition resulted in a total richness of 20 families and 29 species for the five woods. The total tree density had a maximum media of 1207 ind/ha and a minimum of 747 ind/ha. Sebastiania serrata presented the highest importance value and Myrtaceae was the most represented family. The specific diversity was low, varying from 1,08 to 2,38 (nats). In the mutualistic system, 29 species interacting (birds and plants) were registered, with a connectance of 23,9%. Turdus amaurochalinus and T. rufiventris interacted with most tree species and had the highest importance index, being characterized as the main potential dispersers. Ocotea pulchella and Myrsine spp. were registered with the higher number of consumption events, although, Ficus organesis interacted with more frugivorous species, besides having the higher importance in the birds diet. There were variations in the frugivory events number throughout the seasons, as well as in the number of frugivorous species and consumed tree species. The regenerating component presented specific richness and diversity similar with the adult tree stratum, reflecting a floristic similarity higher than 70%. Most species (73,7%) presented negative regeneration rates, revealing the inverted 'J' pattern. The results point to the existence of differences in the forests tree composition and structure among the Restinga woods, besides a good regeneration capacity for most plant species studied. The data also reveal a generalist dispersal system, in which few bird species interact with many tree species and vice-versa.