Les laves provenant de l’arc des Petites Antilles sont caractérisées par une grande variabilité chimique et leurs compositions isotopiques suggèrent une contribution variable de matériel crustal ancien dans leur genèse. L’arc des Petites Antilles est également caractérisé par une zonation chimique nord-sud, les laves des îles du sud présentant généralement des signatures isotopiques crustales plus fortes que celles des îles du nord. Nous avons tenté dans cette étude d’établir s’il existe des variations de la composition chimique des sédiments entrant en subduction le long de l’arc, et si d’éventuels changements de leur composition peuvent expliquer les variations chimiques observées au sein des laves. Pour ce faire, nous avons réalisé une étude géochimique approfondie (majeurs, traces, isotopes du Sr, du Nd, de l’Hf et du Pb) du flux sédimentaire potentiellement entrant dans la zone de subduction à différentes latitudes. L’échantillonnage comprend des sédiments forés au niveau des sites 543 (nord de l’arc) et 144 (extrême sud de l’arc) lors des campagnes DSDP 78A et 14 respectivement, et des sédiments provenant de l’île de la Barbade (sud de l’arc). <p>Les échantillons présentent une grande hétérogénéité lithologique correspondant globalement à un mélange en proportion variable entre une composante détritique et une composante biogénique (siliceuse ou carbonatée). De plus, au niveau du site 144, des niveaux très riches en matière organique (black shales) datant du Cénomanien supérieur au Santonien (~ 95 à 84 Ma) ont été forés. Ces formations correspondent à l’enregistrement des Oceanic Anoxic Events 2 et 3. Nous avons montré que la « dilution » variable de la fraction détritique par la composante biogénique est le facteur qui contrôle largement les variations de concentrations en éléments traces observées. De plus, nous avons révélé un enrichissement en U extrêmement important au sein des black shales du site 144. Les signatures isotopiques de l’Hf, du Nd et du Pb sont dominées par la composante détritique, alors que celle du Sr, dans le cas d’échantillons riches en carbonates est dominée par celle de l’eau de mer. Les sédiments des trois sites présentent des compositions isotopiques du Pb fortement radiogéniques par rapports aux sédiments océaniques « classiques », que nous avons associées à une forte contribution de matériel issu de l’altération des cratons guyanais et brésilien dans la composante détritique. De plus, la décroissance radioactive de l’U dans les black shales du site 144 a généré des rapports 206-207Pb/204Pb extrêmement radiogéniques. <p>Un mélange entre le manteau appauvri et les sédiments du site 543 reproduit les compositions isotopiques des laves de la partie nord de l’arc. Pour la partie sud de l’arc un mélange entre les sédiments les plus radiogéniques en Pb du site 144 et le manteau appauvri explique les compositions des laves des îles de la Martinique à Grenade. Une contribution croissante des black shales du nord vers le sud est nécessaire, et est de plus en accord avec l’augmentation du nord vers le sud de l’âge du plancher océanique subduit. Enfin, quelques sédiments de l’île de la Barbade présentent certaines caractéristiques compatibles avec leur implication dans la genèse des laves de la partie sud de l’arc.<p> / Doctorat en sciences, Spécialisation géologie / info:eu-repo/semantics/nonPublished

This master's thesis deals with the issue of volcanic ash as a complex and its impact on aviation, including the volcanic activity itself (conditions for its existence, for existence of eruptions and their basic products). In addition, the thesis also deals with effect of volcanic ash on aircraft and airports, possibilities of its detection or monitoring as well as mechanism of its spreading in airspace. The emphasis is laid mainly on air incidents related to volcanic ash and on danger it poses to the airspace of the Czech Republic.

A quartz diorite intrusion of probable early Tertiary age that crops out over at least 6 square miles in the Palo Verde Ranch area in Pinal County, Arizona was mapped as a distinct intrusion. The quartz diorite intrudes an area comprising Pinal Schist, Oracle granite, andesitic flows, granoaplite, and dike rocks including both pegmatite and diabase. Two major physical features, the Owl Head Buttes and Chief Buttes volcanic areas, both remnants of an extensive early Tertiary series of flows of intermediate composition that covered the area, now remain as lava-capped buttes above the pediment. Weak but persistent fracture-controlled copper mineralization is found in the quartz diorite and the Pinal Schist at or near their mutual contacts in the form of chrysocolla, malachite, black copper oxides, chalcocite, chalcopyrite, and bornite, in decreasing order. Pyrite is rare. Alteration related to northeast and northwest-trending fractures increases in intensity from the common propylitic to argillic to the northeast toward the San Juan claims area. A barely discernible increase in copper sulfides mirrors the alteration zoning, although geochemical sampling showed background copper in the quartz diorite to be more uniform away from fractures.

Text in English with abstracts in English, Sesotho and isiXhosa / The importance of investment information seeking cannot be overemphasised. Seeking information to support investment decision-making is a key component of every successful investment business. The literature review revealed that informed investors make greater use of accounting disclosures and non-earnings information in order to form more precise earnings expectations. By contrast, a lack of accurate investment information makes it difficult for investors to decide when to buy, hold or sell their investment. This study investigated information needs and seeking behaviour of black investors in the MTN Asonge scheme in Capricorn District of Limpopo Province. The study endeavoured to acquire understanding of investors’ information needs and how they seek information to support their investment decisions. To this end, a qualitative phenomenological research approach was followed. Purposive snowball sampling was applied to sample the study respondents who were later interviewed. Semi-structured, face-to-face interviews were conducted with six investors to collect data which were subsequently analysed thematically. The three types of information sources identified as core to investment decision-making include personal, online and printed information. The findings showed that although the majority of MTN Asonge investors were aware of different formats in which investment information is available, they did not use modern electronic information storing and retrieval strategies, such as conducting online internet searches to access information published on corporate websites. The respondents experienced various challenges when seeking investment information, opting to rely on personal sources such as friends, close relatives and colleagues. Furthermore, the investors appeared not to be aware of personal information sources such as investment advisors, information brokers, roundtables and one-on-one discussions. The study recommended intensive investor education as well as a comparative investigation of information seeking behaviour amongst other members of BEE investment schemes in South Africa. / Bohlokwa bja go nyaka tshedimošo ya peeletšo bo ka se gatelelwe go fetišiša. Go nyaka tshedimošo ya go thekga tšeo ya sephetho ke karolo ye bohlokwa ya kgwebo ye nngwe le ye nngwe ya peeletšo ye a atlegilego. Tshekatsheko ya dingwalo e utolotše gore babeeletši ba go ba le tsebo ba šomiša ka tshwanelo dikutullo tša tšhupamatlotlo le tshedimošo ye e sego ya go tsenya letseno, go bopa gagolo ditetelo tše itšeng tša letseno. Ka go le lengwe, tlhokego ya tshedimošo ya peeletšo ye e nepagetšego e dira gore go be boima go babeeletši go tšea sephetho sa gore ke neng mo ba rekago, swarelelago goba go rekiša peeletšo ya bona. Nyakišišo ye e nyakišišitše dinyakwa tša tshedimošo le mokgwa wa go nyaka tshedimošo ya babeeletši ba bathobaso ka gare ga sekema sa MTN Asonge ka seleteng sa Capricorn sa Profentshe ya Limpopo. Nyakišišo e lekile go hwetša kwešišo ya dinyakwa tša tshedimošo ya babeeletši le ka fao ba nyakang tshedimošo ya go thekga diphetho tša peeletšo ya bona. Go fihla mo, mokgwa wa khwalithethifi wa nyakišišo wa diponagalo o latetšwe. Go dira sampole ya koketšo ya nepo go šomišitšwe go dira sampole ya bakgathatema ba nyakišišo bao go boledišanwego nabo. Dipoledišano le batho ka o tee ka o tee tša dipotšišo tše di bulegilego di didirilwe ka babeeletši ba selela, go kgoboketša datha yeo morago e sekasekilwego ka tekanyetšo. Mehuta ye meraro ya methopo ya tshedimošo yeo e hlaotšwego bjalo ka ya motheo tšeong ya diphetho tša peeletšo e akaretša ya motho ka noši, onelaene le ya go gatišwa. Dikutullo di laeditše gore le ge bontši bja babeeletši ba MTN Asonge ba be ba lemoga mehuta ya go fapana yeo tshedimošo ya peeletšo e hwetšegago ka yona, ga se ba šomiše mekgwa ya sebjalebjale ya go hwetša le go lota tshedimošo ya ilektroniki, go swana le go dira diphuruphutšo tša inthanete tša onelaene go fihlelela tshedimošo ye e phatlaladitšwego diweposaeteng tša dikgwebo. Bakgathatema ba itemogetše ditlhohlo tša go fapana ge ba nyaka tshedimošo ya peeletšo, ba kgetha go tshepha methopo ya bona ka noši go swana le bagwera, maloko a kgauswi le bašomišane. Gape, babeeletši ba bonagetše ba sa lemoge methopo ya tshedimošo ya batho ka noši go swana le baeletši ba peeletšo, dientšente tša tshedimošo, dikopano le dipoledišano tša batho ka o tee ka o tee. Nyakišišo e šišintše thuto ya babeeletši ye e tseneletšego, le nyakišišo ya papetšo ka go mokgwa wa go nyaka tshedimošo magareng a maloko a mangwe a dikema tša peeletšo tša BEE ka Afrika Borwa. / Nkoka wa ku lava vuxokoxoko bya vuvekisi wu nga ka wu nga tsongahatiwi. Ku lavana na vuxokoxoko bya ku seketela ku endliwa ka swiboho hi vuvekisi i xiyenge xa nkoka swinene eka bindzu ra vuvekisi rin'wana na rin'wana ro humelela. Ku hlayiwa ka matsalwa swi kombe leswo vavekisi lava va nga na vutivi va tirhisa ngopfu ku paluxiwa ka vutivi hi swa malawulelo ya swa timali na vutivi lebyi byi nga vuyeseriku, ku endla leswo ku languteriwa vuvuyerisi byo kotlana swinene. Loko swi pimanisiwa, ku pfumaleka ka vutivi bya vuvekisi swi endla leswo swi nonon'hwa eka vavekisi ku endla swiboho loko va xava, va khoma kumbe ku xavisa vuvekisi bya vona. Dyondzo leyi yi endle vulavisisi hi swilaveko swa vutivi, na matikhomelo yo lava vutivi bya vavekisi va vantima eka xikimu xa MTN Asonge eka distriki ya le Capricorn eka xifundzhankulu xa Limpopo. Vulavisisi lebyi byi na xikongomelo xa ku kuma ku twisisa hi swilaveko swa vutivi eka vavekisi na leswo xana va byi lavisa ku yini vutivi ku seketela swiboho swa vona swa vuvekisi. Mayelana na leswi, ku landzeleriwe fambiselo ra ndzavisiso wa qualitative phenemenological. Ku tirhisiwe sampuli ya fambiselo ra purposeful snowball sampling ku kuma sampuli ya ndzavisiso hi vateka xiavo lava ku nga endliwa mabulu ya interview na vona. Ku endliwe ti-interview na vanhu hi wun'we wun'we leri vitaniwaka semi-structured interview, leswi nga endliwa na vavekisi va ntsevu, ku hlengeleta data, leyi endzhaku ka swona yi nga xopaxopiwa hi tinhlokomhaka to karhi. Minxaka minharhu ya swihlovo swa vutivi swi ve swi voniwa tani hi swa nkoka eka ku endla swiboho hi vuvekisi, ku nga leswi katsaka munhu xiviri, ku kuma vutivi eka inthanete (online) na leswi printiweke. Vuyelo lebyi kumiweke byi kombise leswo hambi loko vunyingi bya vavekisi va MTN Asonge a va twisisa hi tifomete to hambana laha ku kumekaku kona vuviti bya vuvekisi, vavekisi a va tirhisangi vutivi bya elektroniki lebyi hlayisiweke na maqhinga yo byi humesa vutivi bya kona, yo fana na ku secha eka online hi inthanete ku fikelela vutivi lebyi paluxiweke eka ti-website ta khampani. Lava nga hlamula swivutiso va ve na mintlhontlho yo hambana-hambana loko va lava vutivi bya vuvekisi, leswi nga endla leswo va tshembela eka vutivi bya vanhu xiviri, byo fana no byi kuma eka vanghana, va ndyangu na maxaka na vatirhikulobye. Ku ya emahlweni, vavekisi va kombisa ku kala ku twisisa hi swihlovo swa vuviti swo fana na vatsundzuxi hi swa vuvekisi, tibrokhara ta vutivi bya vuvekisi, tinhlengeletano ta vanhu to tsundzuxa na mabulu yo khoma na munhu hi wun'we wun'we. Dyondzo leyi ya ndzavisiso yi bumabumela leswo ku endliwa dyondzo ya vuvekisi, na tindlela to lava vutivi hi ku pimapimanisa eka swikimu swa BEE swa vuvekisi eAfrika Dzonga. / Information Science / M. Inf.

Abstracts in English, Afrikaans, Zulu, Tsonga and Portuguese / The purpose of the study was to develop a model of attitudes toward digital banking, by exploring the relationship between values, culture, the diffusion of innovation and the Technology Acceptance. In addition, actual behaviour in the use of digital banking, as well as the moderating effects of gender, age, education level, income, and urban versus rural backgrounds, was included to provide additional insights into the financial services market in Maputo, Mozambique. A quantitative survey with a convenience sample (n = 403) of bankable individuals (male and female) between the ages of 21 and 60, was conducted from 2015–2018. The findings revealed significant relationships between the variables included in the empirical model. Structural equation modelling indicated that the data were a good fit, resulting from the use of a correlations-derived measurement model. These findings provide new insights into the development of tailor-made digital banking actions to drive usage in different segments, which will contribute to the body of knowledge on consumer behaviour and digital banking adoption and use. / Hierdie studie se doel was om ’n model van ingesteldhede teenoor digitale bankwese te ontwikkel deur ondersoek in te stel na die verband tussen waardes, kultuur, die diffusie van innovering en die aanvaarding van tegnologie. Werklike gedrag wanneer digitale bankwese gebruik word, asook die modererende effek van gender, ouderdom, onderwysvlak, inkomste en stedelike teenoor plattelandse agtergrond, is ingesluit om bykomende insigte te verkry in die finansiëledienstemark in Maputo, Mosambiek. ’n Kwantitatiewe opname met ’n gerieflikheidsteekproef (n = 403) van bankbare individue (manlik en vroulik) tussen die ouderdomme 21 tot 60, is in die tydperk 2015 tot 2018 onderneem. Die bevindinge toon dat daar beduidende verbande is tussen die veranderlikes wat by die empiriese model ingesluit word. Die modellering van strukturele vergelykings toon dat die data goed gepas het omdat ’n korrelasie-afgeleide metingsmodel gebruik is. Hierdie bevindinge lei tot nuwe insigte in die ontwikkeling van pasgemaakte digitalebankwese-aksies om gebruik in verskillende segmente aan te dryf. Dit sal bydra tot die bestaande kennis van verbruikersgedrag en die aanvaarding en gebruik van digitale bankwese. / Inhloso yalolu cwaningo bekuwukwenza imodeli yendlela yokubona mayelana nokusebenzisa ibhangi ngendlela yedijithali, ukuhlola ubudlelwane phakathi kwama-value, usiko, ukusabalala kobuqambi kanye nokwamukelwa kwetheknoloji. Nangaphezu kwalokho, indlela yokuziphatha ekusebenziseni ibhangi ngendlela yedijithali, kanye nemiphumela ethobayo yobulili, iminyaka yobudala, izinga lemfundo, ingeniso, kanye nokuqhathanisa abasemadolobheni nabasemakhaya, kwabandakanywa ukuhlinzeka ngemibono engezelelekile kwimakethe yamasevisi ezezimali eMaputo eMozambique. Kwenziwe inhlolovo ngobuningi ngesampuli ye-convenience (n = 403) wabantu abasebenzisa ibhangi (abesilisa nabesimame) abaphakathi kweminyaka engu 21 kanye nengu 60 kwenziwe ukusukela ku 2015–2018 Imiphumela iveza ubudlelwane obubalulekile phakathi kwezinto ezehlukene ezibandakanya imodeli yobufakazi obubambekayo. I-structural equation modelling ikhombise ukuthi ulwazi belungoluhambisana kahle, ngokuvela kumphumela wokusebenzisa i-correlations-derived measurement model. Okutholakele kunikeza imibono emisha ngokukuthuthukiswa kwezinyathelo zokusebenzisa ibhangii ngendlela yedijithali okuhlinzekelwa abantu ngokuhambisana nabo, ukuphakamisa ukusetshenziswa ngabantu bemikhakha ehlukene, lokhu okuthela esivivaneni kumthamo wolwazi ngendlela yokuziphatha kwabasebenzisi, kanye nokwamukelwa kokusebenzisa ibhangi ngendlela yedijithali kanye nokusetshenziswa. / O presente estudo tinha como objectivo desenvolver um modelo de atitudes em relação à banca electrónica explorando a relação entre os Valores, a Cultura e a Difusão da Inovação e Aceitação de Tecnologias. Além disso, o comportamento real relacionado com o uso de serviços da banca electrónica, assim como o efeito moderador do género, idade, nível de escolaridade, rendimentos e os contextos urbano versus rural foram incluídos para permitir melhor compreensão do mercado de serviços financeiros de Moçambique (Maputo). De 2015 a 2018, fez-se um inquérito quantitativo em uma amostra de conveniência (n = 403) de indivíduos bancáveis (masculinos e femininos) com idades compreendidas entre os 21 e os 60 anos. Os resultados revelaram relações significativas entre as variáveis incluídas no modelo empírico. A modelagem de equações estruturais indicou um bom número de dados, o que resultou num modelo canónico de medição derivada de correlações. Ademais, faz-se uma exposição e interpretação de achados sensíveis sob o ponto de vista ético no contexto de banca electrónica baseado no consumidor. Estes achados servirão de base para um novo conhecimento para o desenvolvimento de acções de banca electrónica personalizadas com vista a incentivar o uso em diferentes segmentos, o que acrescentará valor ao conhecimento actual sobre o Comportamento do Consumidor e a utilização de serviços de banca electrónica. / Xikongomelo xa dyondzo leyi a ku ri ku hlamusela malangutelo ya vanhu ehenhla ka ku tirhisiwa ka bangi ya internet hi ku kambisisa vuxaka lebyi nga kona exikarhi ka Mikhuva, Ndhavuko ni ku Haxiwa ka Switirhisiwa Swintswha ni leswi thyiwaka ku amukeriwa ka thekinoloji. Ku engetela kwalaho, ku katsiwile mikhuva ya vhanu ehenhleni ka ku tirhisa bangi ya internet, ku katsa ni vuyelo leri ringaniselaka ro va munhu a ri wanuna kumbe wansati, ntanga, dyondzo, muholo, ni leswaku u tshama dorobeni kumbe emakaya, leswaku ku twisisiwa hi vuenti leswaku mintirho ya swa timali yi tshamise ku yini eMozambique (Maputo). Nxaxamelo wa swivutiso swo teka tinhlayo wu tirhisiwile eka ntlawa lowu voniweke wu ringana (n = 403) wa vanhu lava nga tirhisaka bangi (va xinuna ni va xisati), lava nga ni 21 ku ya ka 60 wa malembe ku sukela 2017 ku ya ka 2018. Tinhlamulo ti kombe leswaku ku ni ku yelana lokukulu exikarhi ka swivutiso leswi katsiweke eka xivumbeko xo hlamusela ha xona. Structural equation modelling yi kombe leswaku ku ni mihandzu yo tala, leswi endleke leswaku ku va ni xivumbeko lexi se xi tiviwaka xa mpimo lowu taka hi ka ku yelana ka swilo (correlations-derived measurement model). Mihandzu leyi yelanaka ni swilo leswi khumbaka mahanyela lamanene leswi lavaka ku voniwa hi vukheta na yona ya vikiwa yi tlhela yi hlamuseriwa hi ku landza matirhelo ya bangi ya internet hi ku ya vatirhisi va yona. Mihandzu leyi yi ta tisa vutisi byintswha leswaku ku makiwa mintirho ya bangi ya internet leyi tivaka ku tsakisa mutirhisi leswaku ku engeteriwa ku tirhisiwa ka yona exikarhi ka mintlawa yo hambana, leswi na swona swi nga ta engetela vutivi ehenhleni ka Mikhuva ya Vatirhisi ni matirhiselo ya bangi ya internet. / Industrial and Organisational Psychology / Ph. D. (Industrial and Organisational Psychology)