• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 21
  • 8
  • 6
  • 5
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 56
  • 9
  • 9
  • 9
  • 7
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Pásy kolem komunikací jako biotop organismů. / The belts along the roads as a biotope for organisms.

KRHUTOVÁ, Stanislava January 2007 (has links)
The aim of the work was to describe the biodiversity of model groups of organisms (vascular plants, epigeic beetles and small mammals) in six transect crossing the two year old high way situated close to the town Písek (South Bohemia). The different methods were used for studied groups (phytocenological mapping, pitfall traps and mousetraps). The results documented the possibility of all studied organisms for the quick recolonization of new biotopes beside of the high way.
22

Professional development of academic staff in private higher education / Living theory / Mentorship

Boshoff, Annette January 2014 (has links)
A common phenomenon in the private higher education environment is that lecturers are highly qualified subject specialists and conduct research mainly in areas in their fields of expertise. Therefore they are not always well informed about the dynamics of the global educational environment and they do not have an indepth knowledge of how learning takes place. As a result of this the traditional lecturing style is mainly used during contact sessions and mostly theoretical knowledge is assessed in written examinations. During class visits that were conducted as part of my duties as quality assurer of the teaching, learning and assessment that take place in the Production Management Institute of Southern Africa (Pty) Ltd (trading as PMI), a private higher education institution, it was noticed that the facilitators of learning present mostly lectures that are based on one-way communication with very little student participation. Learning style flexibility and allowing active student participation during the contact sessions are, in most instances, not considered. This lecturer-centred practice prevents the students from developing responsibility for their own learning process and creating an interest in becoming lifelong learners. An action research-driven professional development programme was presented to the academic staff of PMI to allow them the opportunity to develop innovative facilitation of learning practices. The programme aimed to create a scholarly approach to establishing a culture of lifelong learning in the private higher education environment – in literature commonly referred to as a scholarship of learning and teaching. The academic staff members conducted action research on their own practices as facilitators and assessors of lifelong learning. I conducted living theory action research on my style of being a mentor for the participants of the project. The programme commenced in 2009. The content of and the level on which the programme was presented are in line with a Postgraduate Certificate in Higher Education (PGCHE) that is offered at a public institution. The participants were introduced to, inter alia, the principles of the Ned Herrmann Whole Brain® theory, Gardner’s multiple intelligence theory and Bloom’s taxonomy of cognitive levels. As the first step in the programme all the participants completed the on-line Herrmann Brain Dominance Instrument® (HBDI®). An accredited Hermann Brain Dominance practitioner was contracted to provide feedback to the participants and to explain the principles of this instrument. The HBDI® practitioner is affiliated on a full-time basis with the education faculty of a public higher education institution. He was contracted to facilitate the professional development programme as well. The success of the programme became evident through student feedback and requests, and feedback received from the participating facilitators of learning. Top level management of PMI also became aware of the successes and it resulted in the inclusion of the development of the academic staff members as one of the main focus areas in the strategic management plan for 2010. It was decided that the programme should be repeated every year in order to ensure the continuous professional development of existing and new academic staff members. PMI was invited to offer the programme in the Agriculture and Science Faculty of a public university. Parts of the project were showcased at the 2010 and 2012 conferences of the Higher Education Learning and Teaching Association of South Africa (HELTASA) and the Knowledge 2011 international conference. / Thesis (PhD)--University of Pretoria, 2014. / lk2014 / Humanities Education / PhD / Unrestricted
23

Framing biodiversity conservation discourses in South Africa: emerging realities and conflicting agendas within the Great Limpopo transfrontier conservation area

Whande, Webster January 2009 (has links)
Philosophiae Doctor - PhD / This dissertation explores local people's framing of externally driven biodiversity conservation approaches in the context of transfrontier conservation initiatives. It uses data from the Madimbo corridor, a specific locality within the Great Limpopo Transfrontier Conservation Area, situated to the northeast of South Africa along the South Africa-Zimbabwe boundary. It shows that livelihoods, historical experiences with external interventions and exclusion from policy-making processes and programme implementation influence local strategies for engaging with external interventions. Thus, an analysis of framing of external interventions at a local level should establish the following: the role of natural resources in sustaining local livelihoods; local historical experiences with an external intervention; iii) the nature of multi-level actor interactions from local resource dependent people, to national, regional and global actors involved in or affected by an intervention. The study uses a detailed case study of Bennde Mutale village to trace local people's ideas, ways of speaking and actions in response to the implementation of a large-scale transfrontier conservation initiative. The study finds that local livelihoods play a central role in local responses to the changes that transfrontier conservation bring upon people's lives. Many see further exclusion, while some also see and hope for a restoration of the socio-cultural border region. The globally significant biodiversity - to be conserved for 'future generations' - at the same time constitutes the natural resources that sustain local people's livelihoods. Further, local livelihoods are more diverse than is commonly acknowledged in literature advocating for transfrontier conservation. This lack of acknowledgement of local diversification contributes to the main observation made in this study: that current processes of transfrontier conservation end up replicating and re-inventing the multiple forms of exclusion that have characterised state conservation practices for over a century. While transfrontier conservation enables the freer movement of wildlife, it in fact further constrains the movements of people whose mobility within less closely controlled border regions remains centrally important to survival. At the same time, state actors come into the area with contradicting and conflicting demands ranging from the beneficial advocacy role for land rights to the enforcement of conservation through fences and game rangers, experienced as a direct infringement on livelihood possibilities. The study concludes that there is a need to rethink transfrontier conservation interventions. The diversity of local livelihood approaches needs to be considered more centrally and clearer understanding needs to be developed of how the promises of opportunities, betterment of lives and increased human mobility actually unfold in practice. In order to succeed and deliver on site - not only to high-class tourists seeking to view unique biodiversity but to local people - transfrontier conservation efforts need to engage multiple actors directly from the ground up and throughout the process of policy-making, programme conceptualisation and implementation. / South Africa
24

Cohomologie de Dolbeault feuilletée de certaines laminations complexes / Cohomology of some complex laminations

Ben Charrada, Rochdi 29 May 2013 (has links)
Dans cette thèse, nous nous s’intéressons au calcul des groupes de cohomologie de Dolbeault feuilletée H0∗L (M) de certaines laminations complexes. Ceci revient à résoudre le problème du ∂ le long des feuilles ∂Lα = ω. (Ici M est un espace métrique ou une variété dans le cas où L est un feuilletage F.) Trois situations ont été étudiées de manière explicite.1. Soit M = Ω un ouvert de C × R muni du feuilletage F dont les feuilles sont les sections Ωt = {z ∈ C : (z, t) ∈ Ω} ; on dira que F est le feuilletage canonique de Ω. Sous certaines conditions sur Ω et de croissance sur la forme feuilletée ω, nous montrons que l’´équation ∂Fα = ω a une solution.2. On se donne une suite (αn)n≥1 strictement croissante avec α1 = −1 et convergeant vers 1. Dans C × R on considère les points A = (0, 1) et An = (0, αn) pour n ≥ 1. Pour tout n ≥ 1, soient Sn la sphère de C × R de diamètre le segment [AnA] et E la réunion de toutes ces sphères. Alors E est un sous-espace métrique compact et connexe de C × R. Soit γ : E −→ E l’homéomorphisme défini par γ(w,u) = (ρn(w),u) lorsque (w, u) ∈ Sn où ρn est la rotation dans C d’angle 2πn. La suspension de γ donne une lamination complexe L dont les feuilles sont des surfaces de Riemann toutes équivalentes à C*. Pour cet exemple, nous montrons que l’espace vectoriel H01(L) est nul.3. On considère la variété M = C × Rn \ {(0, 0)} (les coordonnées d’un point seront notées (z,t)) qu’on munit du feuilletage complexe F défini par le système différentiel dt1 = • • • = dn = 0. Le difféomorphisme γ : (z, t) ∈ Mf7−→ (λz, λt) ∈ M (avec 0 < λ < 1) agit sur M de façon libre et propre ; en plus, c’est un automorphisme de F ; F induit alors sur le quotient M = M/γ (qui est difféomorphe `à Sn+1 × S1) un feuilletage complexe F par surfaces de Riemann. Nous montrons que les espaces vectoriels de cohomologie de Dolbeault feuilletée H00 F (M) et H01F (M) sont isomorphes à C. / In this thesis, we are interested in computing the foliated Dolbeault cohomology groups H0∗L (M) for some complex laminations. This amounts to solving the problem of the ∂ along the leaves ∂Lα = ω. (Here M is a metric space or a differentiable manifold if L is a foliation F.) Three situations were considered explicitly.1. Let M = Ω be an open set of C×R equipped with the foliation F whose leaves are the sections Ωt = {z ∈ C(z, t) ∈ Ω}; we say that F is the canonical foliation of Ω. Under certain conditions on Ω and growth conditions on the foliated form ω, we show that the equation ∂Fα = ω has a solution.2. Let (αn)n≥1 be a sequence of real numbers, strictly increasing with α1 = −1 and converging to 1. In C × R we consider the points A = (0, 1) and An = (0, αn) for n ≥ 1. For all n ≥ 1, let Sn be the sphere of C × R with a diameter segment [AnA] and E the union of all these spheres. Then E is a compact and connected subset of C × R. Let γ : E −→ E the homeomorphism defined by γ(w,u) = (ρn(w),u), where (w,u) ∈ Sn and ρn is the rotation in C with angle 2πn. The suspension of γ gives rise to a complex lamination L whose leaves are all equivalent Riemann surfaces isomorphic to C∗. For This example we show that the vector space H01 (L) is zero.3. Consider the manifold M = C × Rn \ {(0, 0)} (the coordinates of a point are denoted (z,t)) endowed with the complex foliation F defined by the differential system dt1 = • • • = dn = 0. The diffeomorphism γ : (z, t) ∈ M −→ (λz, λt) ∈ M (where 0 < λ < 1) acts on M freely and properly ; moreover it is an automorphism of the complex foliation F ; then F induces on the quotient M = M/γ (which is diffeomorphic to S n+1 × S1) a complex foliation F by Riemann surfaces. All leaves are isomorphic to C except one of them which is an elliptic curve. We show that the vector spaces H00 F (M) and H01F (M) of foliated Dolbeault cohomology are isomorphic to C.
25

Site selection and community participation in the development of Gracilaria Gracilts (stackhouse) steentoft, irvine and farnham mariculture in the Western Cape province, South Africa.

Brown, Bernadette January 1999 (has links)
Magister Artium (Development Studies) - MA(DVS) / The seaweed Gracilaria gracilis has been shown in previous studies to have potential for mariculture along the West Coast of South Africa. However, the selection of suitable sites is crucial for the success of a farming enterprise. The variables important in the success or sustainability of suspended raft culture, and the environmental factors influencing these variables, were identified through a literature review. A suitable site was defined as a site with surface water temperature of between 10 and 17 "C, water depth of between 2 and 10 m below surface, and wave heights of less than 4 m. Data and information about these factors were obtained from sources such as the Sea Fisheries Research Institute, the SADCO database, the CSIR and from volunteers in St Helena Bay. The objectives of this study were to convert available data into formats that could be used in a Geographical Information System (GIS), and to predict suitable and available sites for suspended cultivation of Gracilaria gracilis in Saldanha Bay, Langebaan Lagoon and St. Helena Bay. Data were converted to digital format and data layers created. Each data layer represented suitable and unsuitable areas. Areas with existing mariculture, harbours, ship traffic zones and other uses were excluded to determine the real available areas. The Saldanha Bay-Langebaan lagoon system and St Helena Bay, have sites that show potential for suspended cultivation of G. eracilis. The total sizes of the areas selected as suitable are 975.4 ha in Saldanha Bay and 474.8 ha in St. Helena Bay. Some sites predicted as suitable are located in areas known to be subject to conditions not suitable for seaweed mariculture, and led to the conclusion that the accuracy of input data or method of analysis must be improved.
26

2-d Modeling Of A Proton Exchange Membrane Fuel Cell

Agar, Ertan 01 February 2010 (has links) (PDF)
In this thesis, a Proton Exchange Membrane Fuel Cell is modeled with COMSOL Multiphysics software. A cross-section that is perpendicular to the flow direction is modeled in a 2-D, steady-state, one-phase and isothermal configuration. Anode, cathode and membrane are used as subdomains and serpentine flow channels define the flow field . The flow velocity is defined at the catalyst layers as boundary conditions with respect to the current density that is obtained by using an agglomerate approach at the catalyst layer with the help of fundamental electrochemical equations. Darcy&rsquo / s Law is used for modeling the porous media flow. To investigate the effects of species depletion along the flow channels, a different type of cross-section that is parallel to the flow direction is modeled by adding flow channels as a subdomain to the anode and cathode. Differently, Brinkman Equations are used to define flow in the porous electrodes and the free flow in the channels is modeled with Navier-Stokes equations. By running parallel-to-flow model, mass fractions of species at three different locations (the inlet, the center and the exit of the channel) are predicted for different cell po- tentials. These mass fractions are used as inputs to the perpendicular-to-flow model to obtain performance curves. Finally, by maintaining restricted amount of species by having a very low pressure difference along the channel to represent a single mid-cell of a fuel cell stack, a species depletion problem is detected. If the cell potential is decreased beyond a critical value, this phenomenon causes dead places at which the reaction does not take place. Therefore, at these dead places the current density goes to zero unexpectedly.
27

Prêmio por controle no mercado brasileiro

Souza, Vitor Frango de 30 January 2014 (has links)
Submitted by Vitor Frango (vitorpollo@yahoo.com.br) on 2014-03-10T14:51:32Z No. of bitstreams: 1 Dissertação Vitor Frango.pdf: 552731 bytes, checksum: be98ecc9e672434717e644336c1c4c32 (MD5) / Approved for entry into archive by JOANA MARTORINI (joana.martorini@fgv.br) on 2014-03-10T14:58:20Z (GMT) No. of bitstreams: 1 Dissertação Vitor Frango.pdf: 552731 bytes, checksum: be98ecc9e672434717e644336c1c4c32 (MD5) / Made available in DSpace on 2014-03-10T15:43:21Z (GMT). No. of bitstreams: 1 Dissertação Vitor Frango.pdf: 552731 bytes, checksum: be98ecc9e672434717e644336c1c4c32 (MD5) Previous issue date: 2014-01-30 / This study aims to estimate the control premium in the Brazilian stock market, based on the price differential between classes of stocks with different voting rights. In Brazil for the period from 01/07/2003 to 28/06/2013 the average control premium is positive, a result that differs from those found in previous studies, where the control premium is negative. This paper investigates the determinants that imply this voting shares valuation relative to the non-voting share. Particularly, the paper analyzes the impact of the liquidity, dividends differential, the negative impact of the extension of the right of the Tag Along for non-voting shares, the negative impact of ADR companies, a negative impact when firms are classified with upper level corporate governance in BMF&Bovespa. Finally, the positive impact when the major shareholder holding more than 50% of the voting shares and government holding more than 20% of voting shares. / Este trabalho visa estimar o prêmio por controle no mercado acionário brasileiro, com base no diferencial de preços entre espécies de ações com direitos diferenciados de voto. No Brasil para o período de 01/07/2003 a 28/06/2013 a média do prêmio por controle foi positivo, resultado que difere dos encontrados em estudos anteriores, onde o prêmio por controle é negativo. Este trabalho investiga os determinantes que implicam na valorização da ação ordinária em relação à ação preferencial. Em particular, o trabalho analisa os impactos da liquidez, do diferencial dos dividendos, o impacto negativo da extensão do direito do Tag Along para ações preferenciais, o impacto negativo das empresas que possuem ADR, impacto negativo quando a empresas está classificada com nível superior de governança corporativo da BMF&Bovespa e pro fim, o impacto positivo para quando o acionista majoritário detêm mais de 50% das ações ordinárias e da participação do governo nas empresas que possui 20% das ações ordinárias.
28

Variace frakcionálních procesů / Variation of Fractional Processes

Kiška, Boris January 2022 (has links)
In this thesis, we study various notions of variation of certain stochastic processes, namely $p$-variation, pathwise $p$-th variation along sequence of partitions and $p$-th variation along sequence of partitions. We study these concepts for fractional Brownian motions and Rosenblatt processes. A fractional Brownian motion is a Gaussian process and it has been intensively developed and studied over the last two decades because of its importance in modeling various phenomena. On the other hand, a Rosenblatt process, which is a non- Gaussian process that can be used for modeling non-Gaussian fluctuations, has not been getting as much attention as fractional Brownian motion. For that reason, we concentrate in this thesis on this process and we present some original results that deal with ergodicity, $p$-variation, pathwise $p$-th variation along sequence of partitions and $p$-th variation along sequence of partitions. Boris Kiška
29

exploring pre-loved : consumers’ perception of the pre-loved concept in a traditional clothing store environment

Connysson, Linnéa, Landström, Emma January 2024 (has links)
The aim of this thesis is to explore consumer perceptions regarding the emerging trend among traditional clothing stores in Gothenburg, Sweden, where a section of their retail space is dedicated to reselling pre-loved clothing. Additionally, it seeks to investigate the factors influencing consumers' preference for these sections over conventional thrift stores. Employing a qualitative approach, the study conducts 10 shop-along sessions comprising semi-structured interviews and unstructured observations in four traditional clothing stores, each featuring an integrated pre-loved section. The theoretical framework encompasses consumer value theory, supplemented by the Means-End Chain Theory, which is utilized to analyze the findings. Results reveal a positive response from participants toward pre-loved initiatives, indicating an overall favorable perception. Findings show that consumers perceive pre-loved initiatives as multiple valuable, including economic savings, functional quality, social value, and an enjoyable, empowering, and satisfying experience. Furthermore, various factors such as curated pieces, well-organized sections, unique garments, and diverse assortments influence consumers, leading to different consequences and values such as feeling efficient, self-fulfillment/self-expression, and enjoyment, thus favoring pre-loved initiatives over conventional thrift stores. In conclusion, the study sheds light on the growing preference for pre-loved initiatives among consumers in traditional clothing stores.
30

L'éclatement en géométrie algébrique, différentielle et symplectique

Herrera-Cordero, Esteban 04 1900 (has links)
L'éclatement est une transformation jouant un rôle important en géométrie, car il permet de résoudre des singularités, de relier des variétés birationnellement équivalentes, et de construire des variétés possédant des propriétés inédites. Ce mémoire présente d'abord l'éclatement tel que développé en géométrie algébrique classique. Nous l'étudierons pour le cas des variétés affines et (quasi-)projectives, en un point, et le long d'un idéal et d'une sous-variété. Nous poursuivrons en étudiant l'extension de cette construction à la catégorie différentiable, sur les corps réels et complexes, en un point et le long d'une sous-variété. Nous conclurons cette section en explorant un exemple de résolution de singularité. Ensuite nous passerons à la catégorie symplectique, où nous ferons la même chose que pour le cas différentiable complexe, en portant une attention particulière à la forme symplectique définie sur la variété. Nous terminerons en étudiant un théorème dû à François Lalonde, où l'éclatement joue un rôle clé dans la démonstration. Ce théorème affirme que toute 4-variété fibrée par des 2-sphères sur une surface de Riemann, et différente du produit cartésien de deux 2-sphères, peut être équipée d'une 2-forme qui lui confère une structure symplectique réglée par des courbes holomorphes par rapport à sa structure presque complexe, et telle que l'aire symplectique de la base est inférieure à la capacité de la variété. La preuve repose sur l'utilisation de l'éclatement symplectique. En effet, en éclatant symplectiquement une boule contenue dans la 4-variété, il est possible d'obtenir une fibration contenant deux sphères d'auto-intersection -1 distinctes: la pré-image du point où est fait l'éclatement complexe usuel, et la transformation propre de la fibre. Ces dernières sont dites exceptionnelles, et donc il est possible de procéder à l'inverse de l'éclatement - la contraction - sur chacune d'elles. En l'accomplissant sur la deuxième, nous obtenons une variété minimale, et en combinant les informations sur les aires symplectiques de ses classes d'homologies et de celles de la variété originale nous obtenons le résultat. / The blow-up is a transformation which plays an important role in geometry, because it can be used to resolve singularities, relate birationally equivalent varieties, and construct varieties with new properties. This thesis first presents blowing-up as developped in classical algebraic geometry. We will study it in the case of affine and (quasi-)projective varieties, on a point and along an ideal and a subvariety. Then a discussion about its extension to the differential category will be carried out, over the real and complex fields, on a point and along a submanifold. An example of a resolution of singularity will then follow. Subsequently we will discuss blowing-up in the symplectic category, where we will do the same as for complex manifolds, paying careful attention to the symplectic form. To conclude, we will study a theorem by François Lalonde, where the symplectic blow-up plays a major part in proof. This theorem states that any 4-variety fibered by 2-spheres over a Riemann surface, and different than the Cartesian product of two 2-spheres, can be equiped with a 2-form giving it a symplectic structure ruled by curves that are holomorphic with respect to its almost-complex structure, and such that the symplectic area of the base is smaller that the capacity of the variety. In the proof, we blow up a ball in the 4-variety, and obtain a fibration containing two distinct spheres with a self-intersection equal to -1: the pre-image of the point where the usual complex blow-up is done, and the proper transform of the fiber. These two are exceptional, so it is possible to do the inverse operation - the blow down - on each of them. By blowing down the latter, we get a minimal variety, and by combining information about the symplectic area of its homology classes and of those of the original variety, we obtain the result.

Page generated in 0.0294 seconds