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  • 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.
331

Influência do ambiente e relações predador-presa em uma comunidade de mamíferos terrestres de médio e grande porte em Floresta Ombrófila Densa / Influence of environmental conditions and predator-prey relationship in a community of medium and large sized terrestrial mammal in dense rain forest

Maísa Ziviani Alves 25 May 2016 (has links)
A destruição de florestas tropicais é intensa e pode levar à extinção de espécies sensíveis à fragmentação. Na Mata Atlântica, mamíferos com importantes funções no equilíbrio do ecossistema, como Panthera onca (onça-pintada), já estão ausentes em grande parte do bioma. Logo, é de extrema urgência compreender os processos que influenciam na permanência dessas espécies em uma área, para evitar futuras extinções locais. Assim, o objetivo geral deste estudo foi analisar as influências das características ambientais sobre a riqueza e ocorrência de mamíferos terrestres de médio e grande porte e as relações espaço-temporais entre o predador de topo, mesopredadores e presas em uma área de Mata Atlântica contíngua ao Parque Estadual da Serra do Mar com recente histórico de perturbação (Parque das Neblinas, Bertioga, SP). A coleta de dados foi realizada por armadilhamento fotográfico, durante 90 dias em 2013 e 2014, em 27 pontos amostrais, distantes 1 km entre si. As características ambientais avaliadas foram altitude, densidade de drenagem, precipitação média, temperatura média, número de palmitos (Euterpe edulis) e presença de trilhas naturais. Para analisar as influências do ambiente sobre a riqueza e ocorrência de espécies (com mais de três registros por ano) foram utilizados Modelos Lineares Generalizados. Para as demais análises, as espécies foram agrupadas em predador, mesopredadores, presas de grande, médio e pequeno porte. O período e sobreposição de atividade destes grupos foram estimados por meio da densidade de Kernel. A abundância foi estimada para mesopredadores e presas, através de modelos N-mixture. Para analisar a probabilidade de ocupação e detecção do predador de topo foram usados modelos de ocupação single-season. Foram amostrados 18 mamíferos terrestres de médio e grande porte, dos quais nove estão ameaçados de extinção ((Cabassous unicinctus (tatu-de-rabo-mole), Cuniculus paca (paca), Leopardus guttulus (gato-do-mato-pequeno), Leopardus pardalis (jaguatirica), Leopardus wiedii (gato-maracajá), Pecari tajacu (cateto), Puma concolor (onça-parda), Puma yagouaroundi (gato-mourisco) e Tapirus terrestris (anta)). A riqueza de espécies foi positivamente influenciada pelo maior volume de chuvas e a ocorrência da maioria das espécies (C. unicinctus, Dasypus novemcinctus (tatu-galinha), P. concolor, Sylvilagus brasiliensis (tapiti) e T. terrestris) foi influenciada pela densidade de drenagem em 2013. Em 2014, a riqueza não foi explicada por nenhuma característica e apenas quatro espécies sofreram influência de alguma característica ambiental. O predador de topo registrado foi catemeral, os mesopredadores e presas de grande porte mostraram-se mais noturnos e presas de médio e pequeno porte foram mais diurnas. Presas menores apresentaram a maior sobreposição total com o predador (Δ1=0,72). A influência sobre a probabilidade de ocupação da área pelo predador variou entre os anos, tendo sido pela abundância de presas de grande e pequeno porte, em 2013, e pela abundância de presas de médio porte, em 2014. A detecção foi influenciada apenas em 2014, de forma negativa pelas ocasiões. A partir destes resultados foi possível identificar as características ambientais que devem ser mantidas na área, como a disponibilidade de recursos hídricos e abundância de presas, a fim de conservar das espécies resilientes. / The destruction of tropical forests is alarming and may lead to the extinction of species susceptible to fragmentation. In the Atlantic Forest, mammals with important functions in the ecosystem balance, such as Panthera onca (jaguar), are already absent in part of the biome. Therefore, it is urgent to understand the processes that influence the permanence of these species in an area, in order to prevent future local extinctions. Thus, this study aimed to analyze the influence of environmental characteristics on the richness and occurrence of terrestrial mammals of medium and large size; as well as the spatio-temporal relationship between the top predator, mesopredator and preys, in the Atlantic foreste area continuos continuous with Serra do Mar State Park, with recent degradation history (Neblinas Park, Bertioga, State of São Paulo). Sample data was collected by camera trapping for 90 days in 2013 and 2014, 27 sampling points 1km distant from each other. The environmental characteristics were altitude, drainage density, average rainfall, average temperature, number of palm hearts (Euterpe edulis) and the presence of nature trails. Generalized Linear Models were used to analyze the environmental influences on the richness and occurrence of species (with more than 3 records per year). For the other analyses, species were grouped into predator, mesopredators, preys of large, medium and small size. The period and overlap activity of these groups were estimated by the Kernel density. Abundance was estimated for mesopredators and prey through N-mixture models. Single-season occupancy models were used to analyze the probability of occupancy and detection of top predators. A total of 18 terrestrial mammals of medium and large size were sampled, with nine of them being threatened with extinction: Cabassous unicinctus (naked-tailed armadillo), Cuniculus paca (paca), Leopardus guttulus (oncilla), Leopardus pardalis (ocelot), Leopardus wiedii (margay), Pecari tajacu (collared peccary), Puma concolor (cougar), Puma yagouaroundi (jaguarundi) and Tapirus terrestris (tapir). In the 2013, the species richness was positively influenced by the largest volume of precipitation and the species occurrence (C. unicinctus, Dasypus novemcinctus (tatu-galinha), P. concolor, Sylvilagus brasiliensis (tapiti) e T. terrestris) was interfered by the drainage density. In 2014, richness was not explained by any of the environmental characteristics mentioned and only four species have suffered influence of them. The top predator recorded was catemeral, the mesopredator and large prey were mainly nocturnal and prey of medium and small size were mainly daylight. Smaller prey had the highest total overlap with the predator (Δ1=0.72). The influence on the probability of occupancy of the area by the predator varied between the years: in 2013 it was the abundance of large and small preys, and in 2014, the influence was the abundance of medium preys. The detection was negatively influenced by the occasion only in 2014. Our findings showed the environmental characteristics that should be maintained in the area, such as water resources and abundance of prey, for conservation of Atlantic Forest and its fauna community.
332

Adaptation to growing season length in the perennial <em>Arabidopsis lyrata</em>

Kemi, U. (Ulla) 03 December 2013 (has links)
Abstract Adaptation to local environment is important for all organisms to guarantee survival and to maximize reproduction. Populations of the same species may live in environments that differ markedly. Due to differential selection pressures this can lead to population differentiation, which can be studied both at the phenotypic and at the gene level. The growing season cued by long days is typically short in the north, whereas southern populations have long growing seasons and are adapted to short days. Seasonal fluctuations in temperature also differ between northern and southern environments. Daylength and temperature regulate the timing of flowering in plants. Environmental regulation of flowering and its genetic basis has been extensively studied in the annual model species Arabidopsis thaliana. The perennial growth and flowering habit has been studied especially in trees, but studies on herbaceous plants species have been lacking. In this thesis, I have studied adaptation to growing season length in a perennial herbaceous model species Arabidopsis lyrata. Individuals from populations adapted to northern and southern environments in Europe were grown in same conditions in the growth chambers and in the field. Differentiation between the populations was studied by observing their flowering phenotypes and by studying the expression of genes that are candidates for governing the phenotypic differentiation. The main result in the thesis was that adaptation to short growing season in north can be seen as long daylength requirement for flowering and as fast developmental rate. Critical daylength for flowering likely regulates especially the timing of flowering cessation in the end of the growing season. Flowering time of individuals from northern populations also responded more strongly to cold treatment (representing winter) than that of the southern population. The cold requirement for flowering guarantees that the plants only flower after the winter in the spring with suitable conditions. Expression studies indicated that population differentiation in flowering could be at least partly governed by the expression variation in a few candidate genes. The results in this thesis are valuable for instance for understanding perennial species in general, including tree and crop species, and for predicting how plants response to changing climate. / Tiivistelmä Ympäröiviin oloihin sopeutuminen on tärkeää kaikille organismeille selviytymisen ja jälkeläistuoton kannalta. Saman lajin eri populaatiot saattavat elää ympäristöissä, joiden olosuhteet poikkeavat toisistaan huomattavasti. Tällöin populaatioihin kohdistuvat erilaiset valintapaineet ja populaatiot erilaistuvat. Erilaistuminen havaitaan tarkastelemalla yksilöiden ilmiasuja ja geenejä. Kasvukauden pituus määrittää eteläisten ja pohjoisten kasvuympäristöjen valintapaineita. Pohjoisessa kasvukausi on lyhyt ja sen alkamisesta ja loppumisesta kertoo pitkä päivänpituus. Etelässä on pitkä kasvukausi ja siellä elävät populaatiot ovat sopeutuneet lyhyeen päivänpituuteen. Myös vuodenaikaiset lämpötilavaihtelut eroavat pohjoisten ja eteläisten alueiden välillä. Muutokset päivänpituudessa ja lämpötilassa säätelevät kasveilla kukkimisen ajankohtaa. Kukkimiseen vaikuttavia ympäristötekijöitä ja kukkimista sääteleviä geenejä on tutkittu paljon yksivuotisella mallilajilla lituruoholla (Arabidopsis thaliana). Monivuotisten kasvien kasvun ja kukkimisen säätelyä on tutkittu etenkin puilla, mutta hyvin vähän ruohovartisilla kasveilla. Tässä väitöskirjatyössä tutkin kasvukauden pituuteen sopeutumista monivuotisella ruohovartisella lajilla, idänpitkäpalolla (Arabidopsis lyrata). Pohjoisiin ja eteläisiin ympäristöoloihin sopeutuneiden eurooppalaisten populaatioiden yksilöitä kasvatettiin samanlaisissa olosuhteissa kontrolloiduissa kasvatushuoneissa ja kenttäolosuhteissa. Populaatioiden erilaistumista tarkkailtiin kukkimiseen liittyvissä ominaisuuksissa sekä eroja selittävien kandidaattigeenien ekspressiossa. Tutkimuksen päätulos oli, että pohjoisen populaation lyhyeen kasvukauteen sopeutuminen voidaan havaita pitkän päivän vaatimuksena kukkimiselle ja nopeana kehityksenä. Kenttäolosuhteissa päivänpituus sääteli etenkin kukkimisen lopetusta kasvukauden lopussa. Pitkä kylmäkäsittely nopeutti kukkimista etenkin pohjoisessa populaatiossa. Kukkimista edeltävä kylmävaatimus takaa, etteivät kasvit kuki syksyllä epäsuotuisissa olosuhteissa, vaan vasta keväällä talven jälkeen. Populaatioiden erilaistuminen kukkimisen päivänpituus- ja kylmävaatimuksessa selittyy todennäköisesti ainakin osittain kandidaattigeenien ekspressioeroilla. Tämän väitöskirjatyön tuloksia voidaan soveltaa monivuotisten viljelykasvien jalostuksessa tai ennustettaessa kasvipopulaatioiden sopeutumista ilmastonmuutokseen.
333

Barkning av björk i små dimensioner : En studie utförd på uppdrag av IKEA Of Sweden / Debarking birch in small dimensions : A study commissioned by IKEA of Sweden

Hultin, Oscar January 2017 (has links)
Studien är gjord på uppdrag av IKEA och undersöker metoder att barka björk i smådimensioner, med syfte att belysa parametrar som inverkar vid barkning i trumma och utvärdera vilka möjliga kända metoder som finns. Studien behandlar två försök, ett förförsök i form a hydraulisk barkning och ett försök för att belysa parametrar som inverkar vid barkning i trumma. Resultaten visar på att hydraulisk barkning fungerar men vidare studier krävs för utvärdering av kostnad, vattenåtgång och vidare utveckling. Trumbarkningsförsöket visar att basning i förberedande syfte effektiviserar barkningen, virket bör vara av liknande dimension och att barken avlägsnas lättare vid savningsperioden. Inga metoder speciellt anpassade för att barka björk av mindre dimensioner hittades under studien. / he study is made on assignment of IKEA and investigates methods of debarking birch in small dimensions, with the purpose of highlighting parameters that will affect debarking in a drum and evaluating possible known methods. Two attempts is made in the study, an attempt in the form of hydraulic debarking and an attempt to highlight parameters affecting drum debarking. The results show that hydraulic barking works but further studies are required to evaluate cost, water usage and machine development. The drum debarking experiment shows that steaming in preparatory purpose makes the process more effective, logs should be of similar size and the bark will be removed more easily during the sapping season. No methods specifically adapted to debark birch of smaller dimensions was found during the study.
334

Paysages et saisons : les réseaux métaphoriques du réel dans les "Rerum Vulgarium Fragmenta" de Pétrarque / Landscapes and seansons : the metaphorical network of the real in Petrarch's "Rerum Vulgarium Fragmenta"

Filippini, Célia 12 December 2015 (has links)
Cette thèse étudie l'emploi d'environ 640 occurrences relatives au champ sémantique des paysages et des saisons (reliefs, rivages, cours d'eau, végétation, pierres, écueils, neiges et "nebula") dans les "Rerum Vulgarium Fragmenta". C'est l'environnement textuel dans lequel chacune d'elles s'insère qui la distingue des autres et infléchit son signifié ; et en même temps chacune se complète de façon dynamique, interagissant avec toutes celles qui se trouvent sur le même axe paradigmatique. Le premier chapitre étudie leur morphologie de façon contextuelle et intertextuelle, afin de cerner l'isotopie du chronotope dans le "canzoniere" ; on verra par la diversification et l’enrichissement de leurs emplois métaphoriques que les paysages et les saisons s'imposent comme enjeux diégétiques. La composition du "liber" s’inscrivant dans une temporalité complexe qui, pour chacun de ses "fragmenta", brouille la chronologie relative à sa composition, c’est par la prise en compte, dans le deuxième chapitre, de cette double dimension diachronique, qu’il a été possible de mieux appréhender l'évolution continue qui est à l’œuvre dans et par les métaphores. Elles permettent de partir d'une donnée connue (y compris en tant que topos littéraire) pour explorer une réalité (intérieure) autrement insaisissable, le “réel” du poète-amant. Le dernier chapitre nous permettra d'analyser les processus de métaphorisation mis en œuvre par Pétrarque lorsque les reprises du chronotope acquièrent une portée éthique et métapoétique. / My thesis scrutinizes the use of almost 640 occurrences related to the semantic fields of landscapes and seasons (landforms, shores, rivers, vegetation, rocks, reefs, clouds and "nebula") in the "Rerum Vulgarium Fragmenta". It is the textual environment in which each of them fits that distinguishes it from others and bends its signified; and yet they complement one another dynamically, interacting with all those who are on the same paradigmatic axis. The first chapter examines their morphology in a contextual and intertextual way, to identify the chronotope's isotopy in the "canzoniere" ; we will see by the diversification and the enrichment of their metaphorical uses that landscapes and seasons emerge as diegetic issues. The composition of the "liber" partakes of a complex temporality that blurs the chronology of its composition for each of its "fragmenta" ; it is by taking into account, in the second chapter, this double diachronic dimension, that it was possible to better understand the continuing evolution which is at work in and through metaphors. They allow from a known data (including as a literary topos) to explore a reality (indoor) otherwise elusive, the poet-lover's "real". The last chapter will allow us to analyze the metaphorization process implemented by Petrarch when the chronotope's recurrences acquire an ethical and metapoetic scope.
335

'n Prakties-teologiese ondersoek na die gebruik van liturgiese simbole en rituele in die Paassiklus

Uys, Jacobus Stephanus Petrus 29 September 2006 (has links)
Text in Afrikaans This research paper has been prepared against a background of an apparent lack of symbols and rituals in Reformed services of worship. Chapter 1 deals with the importance of symbols and rituals in light of the demands of changing times. It has furthermore been suggested that the Dutch Reformed Church (“DRC”) has a particular problem with the use of symbols and rituals during the Easter Season. The central hypothesis has been formulated as follows: “In the Reformed liturgy it is necessary that the use of liturgical symbols and rituals be adapted to be presented in a way, meaningful and relevant in the world of churchgoers.” Chapter 2 describes the Practical Theological grounds on which the study is based. It has been demonstrated that Practical Theology is a theological science in its own right. The use of liturgy as a communications medium in the proclamation of the gospel allows liturgical symbols and rituals to claim their rightful place. The formulation of liturgical practice must also be determined by and within the background of the local religious community. The outcome of the study of relevant literature is set out in Chapter 3. The Reformed liturgical tradition, when adapted to the demands of changing times, allows for the use of liturgical symbols and rituals during the Easter Season in a concrete form. Liturgy, including all verbal and non verbal liturgical actions, finds its place as a communicative medium in evangelical services. The communications media of the 21st century serve as strong carriers for the formation of liturgy. The traditional Reformed liturgy is enriched by an amalgamated liturgy that is the result of a unique process based on the similar use of symbols and rituals by the various traditional religious groupings. Ritualism is the term used to describe liturgical acts. Symbols and rituals are used as the communication tools to translate the relevance of liturgy into modern life. The Easter Season, with its inherent Christian content, is an ideal opportunity for the use of ritualism. The liturgical symbols and rituals used during Easter must be based on sound Biblical and theological grounds and must be focused on God and the religious requirements of mankind. The maximum use of modern multimedia is necessary out of respect for the experience of the worshipper. The experiences and the senses of man, however, must be accessed under the guidance of the Holy Spirit. As the church is essentially outwardly directed, the <ib>missio Dei</ib> must play its rightful role in the formation of the liturgy. At the end of Chapter 3, a theological theory is put forward suggesting a new and unique proposal on the possible use of symbols and rituals in the Easter Season. Based on a questionnaire, in which the needs and attitudes of worshippers were tested empirically, Chapter 4 indicates that in general their needs are adequately catered for by the current liturgical practices of the Easter Season. However it has also been established that the people do not have a great need for physical symbolism and neither are they keen to become involved in the preparation for or delivery of worship services. Chapter 5 sets out the insights gained from the study of literature and the empirical investigation. It is indicated that the Reformed liturgy, enriched by other media, still has the ability to bring the message of the relevant Christian events of Easter into the world of the worshipper in a meaningful way. Ekserp Hierdie navorsing is gedoen teen die agtergrond van ‘n oënskynlike armoede aan simbole en rituele wat in die Gereformeerde erediens bestaan. In Hoofstuk 1 is die belangrikheid van simbole en rituele in die lig van die eise van veranderende tye, aangetoon. Daar is ook uitgewys dat daar in die NG Kerk ‘n probleem bestaan wat die gebruik van liturgiese simbole en rituele in die Paassiklus betref. Die sentrale hipotese is soos volg geformuleer: “In die Gereformeerde liturgie is dit noodsaaklik dat die gebruik van liturgiese simbole en rituele gedurende die Paassiklus aangepas word om die toepaslike Christusgebeure singewend te verkonkretiseer in die wêreld van erediensgangers”. In Hoofstuk 2 is die Prakties-teologiese vertrekpunte vir die studie beskryf. Daar is uitgewys dat Praktiese Teologie ‘n teologiese wetenskap is. Die liturgie as kommunikatiewe handeling in diens van die evangelie, bied die ruimte waarbinne liturgiese simbole en rituele tot hul reg kom. Die konteks waarin die plaaslike geloofsgemeenskap haarself bevind speel ‘n medebepalende rol in liturgievorming. Hoofstuk 3 dien as resultaat van die literatuurstudie. Die gebruik van liturgiese simbole en rituele in die Paassiklus kry konkreet gestalte in die Gereformeerde liturgiese tradisie met inagneming van die eise van veranderende tye. Liturgie vind plaas as kommunikatiewe handelinge in diens van die evangelie en sluit alle verbale en nieverbale liturgiese handelinge in. Een-en-twintigste eeuse kommunikasiemiddele dien as struktuurdraers vir liturgievorming. Verder verryk konvergensieliturgie die tradisionele Gereformeerde liturgie. Die term ‘samevoegingsliturgie’ is geskep as ‘n unieke proses waarvolgens liturgieë uit verskillende tradisiestrome ‘n sinergerende gebruik van simbole en rituele teweeg bring. Die term ritualiteit word gebruik as aanduiding van die liturgiese handelinge. Simbole en rituele dien as kommunikasiedraers wat mense in kontak met die werklikhede van die lewe bring. Die Paassiklus, met gepaardgaande Christusinhoude, vorm ‘n geskikte medium waarbinne ritualiteit gestalte kry. Liturgiese simbole en rituele in die Paassiklus moet Bybels teologies verantwoord wees. Dit moet gefokus wees op God en antropologies gerig wees. Omdat die ervaring van erediensgangers ernstig geneem word, moet die moderne multimedia maksimaal en konkreet ontgin word. Onder die leiding van die Heilige Gees moet erns gemaak word met die ervaring en sintuie van die mens. Omdat die kerk in wese ook gerig is na ‘buite’, moet die <bi>missio Dei in liturgievorming ‘n regmatige rol speel. Aan die einde van Hoofstuk 3 word ‘n teologiese teorie vir die gebruik van simbole en rituele in die Paassiklus beskryf en aangebied as ‘n besondere bydrae tot ‘n nuwe verstelde praktykteorie. In Hoofstuk 4 is die behoeftes en houdings van erediensgangers met behulp van ‘n vraelys empiries getoets en is bepaal dat daar oorwegend tevredenheid heers oor die bestaande liturgiese praktyke gedurende die Paassiklus. Daar is egter ook vasgestel dat mense nie groot behoefte het aan liggaamlikheid nie en nie begerig is om mee te werk aan die voorbereiding en aanbieding van eredienste nie. In Hoofstuk 5 is die insigte verkry uit die literatuurstudie en die empiriese ondersoek, beskryf. Verskeie verdere navorsingsmoontlikhede is uitgewys en daar is aangetoon dat die Gereformeerde liturgie, met verryking deur ander media, steeds oor die drakrag beskik om die toepaslike Christusgebeure in die Paassiklus singewend te verkonkretiseer in die wêreld van erdiensgangers. / Thesis (DD (PracticalTheology))--University of Pretoria, 2007. / Practical Theology / unrestricted
336

Impact d'une mise en defens temporaire de prairies permanentes durant le pic de floraison : sélection alimentaire des brebis, diversité floristique et entomologique (Lepidoptera, Bombidae, Carabidae) des couverts / Is there a benefit of excluding sheep from permanent pastures at flowering peak ? : diet selection, floristic and insect diversity (Lepidoptera, Bombidae, Carabidae)

Scohier, Alexandra 19 December 2011 (has links)
L’érosion de la biodiversité prairiale est devenue une préoccupation majeure à l’échelle Européenne. Le pâturage ovin est supposé avoir un impact négatif sur la diversité prairiale, en raison de leur forte sélectivité pour les dicotylédones, indispensables aux insectes pollinisateurs. Comparés aux bovins, les ovins structurent peu les couverts et créent également moins de niches écologiques contrastées. L’objectif de cette thèse était de tester la faisabilité, et les bénéfices en pâturage ovin, d’une conduite en rotation dans laquelle une sous-parcelle est temporairement exclue du pâturage au moment du pic de floraison. Les effets de cette conduite ont été comparés à ceux d’un pâturage continu au même chargement. Au delà des indicateurs directs de performances zootechniques et de biodiversité (plantes, papillons, bourdons et carabes), nous avons analysé la sélection alimentaire des brebis dans les deux modes de conduite. Nous avons aussi cherché à appréhender comment la race et la fertilité du milieu pouvaient moduler la faisabilité d’un tel pâturage tournant et son intérêt vis-à-vis de la préservation de la biodiversité. Indépendamment de leur race, les brebis ont présenté une sélection alimentaire accrue vis-à-vis des dicotylédones dans les parcelles pâturées en rotation, qui a rapidement entraîné une diminution de leur richesse floristique en comparaison des parcelles pâturées en continu. L’augmentation de l’intensité de floraison des sous parcelles temporairement exclues de la rotation a favorisé les bourdons, probablement en raison de l’augmentation de la ressource en pollen et en nectar. En revanche, ce mode de gestion n’a pas permis d’augmenter la densité ni la richesse spécifique des papillons et des carabes. Le bénéfice d’une mise en défens temporaire d’une partie des parcelles semble donc moindre qu’en pâturage bovin. Définir les dates de mises en défens par rapport à la floraison d’espèces indicatrices, moduler la durée de la mise en défens en fonction de la pousse de printemps, et prolonger l’exclusion de certaines parcelles en automne et en hiver sont autant de pistes qu’il nous reste à explorer, afin de déterminer les conditions d’application optimale d’une telle conduite. / Biodiversity loss in grasslands is a major concern across Europe. Sheep grazing is rarely considered the best method for delivering conservation objectives, as the result of their strong diet selection on forbs and legumes, which in turn negatively impacts nectar-dependent insect groups. Compared with cattle, sheep also produce a strong homogeneization effect and reduce habitat diversity. The objective of this thesis was to analyze the feasibility and environmental benefits of a rotational grazing management, in which sheep were temporarily excluded from a sub-plot at flowering peak. It was compared with continuous grazing in the same stocking rate. In addition, to measurements of animal performances and biodiversity indicators (plants, butterflies, bumblebees and ground beetles), we analyzed diet selection by ewes in the two grazing managements, and how sheep breed and soil fertility could modulate biodiversity outputs in the rotational management. Independently of sheep breed, the ewes increased their selection of forbs and legumes in rotationally-grazed plots. This rapidly decreased plant species richness in rotationally compared with continuously-grazed plots. However, an increase of flowering intensity in temporarily ungrazed sub-plots benefited bumblebee density and species richness, as predicted by the ‘trophic level’ hypothesis. Rotational grazing management did not increase butterfly and ground beetle densities, which stresses that its benefits would be lesser than in cattle-grazed systems. Defining the exclusion period based on the flowering of indicator plant species, modulating its duration based on spring grass growth, and keeping some sub-plots ungrazed until the end of the grazing season are options that still need to be tested in order to define the optimal conditions for such a rotational grazing management.
337

Effect of phosphorus application on the performance of four cowpea varieties and two maize varieties under strip intercropping in Limpopo Province

Nkuna, Mzamani Knowledge January 2019 (has links)
Thesis (M.Sc. Agriculture (Agronomy)) -- University of Limpopo, 2019 / Limpopo Province is a semi-arid region prone to drought. Crop yields continue to decline due to low soil fertility and poor cropping systems. Cowpea is nutritionally rich in proteins essential for human consumption and livestock feeding. It fixes N2 which becomes available for the succeeding crop in rotation. For this reason, it is used as a companion crop in cereal-legume intercropping systems. Maize is one of the most important grain crops in South Africa, it serves as the major staple food for many households. Phosphorus is one of the macro-nutrient elements required by crops to produce satisfactory yields. The interactions between different rates of P fertilisation and cowpea-maize strip intercropping have not been studied in detail under rain-fed maize-cowpea strip intercropping in Limpopo Province. Many smallholder farmers in Limpopo Province obtain low yields due to the practice of mixed intercropping. Two season (2014/15 and 2015/16) experiments were laid out in a split-split plot design at Syferkuil farm to determine the performance of cowpea and maize varieties in cowpeamaize strip intercropping at varying P application rates. Treatments consisted of factors namely, P levels (0, 15, 30, 45 kg/ha), cropping system (monocropping and intercropping), maize varieties (WE3127 and ZM1423) and cowpea varieties (PAN311, TVu13464, IT86D-1010 and IT82D-889). Data were collected from growth and yield parameters that included (number of days to flowering, plant height, number of days to physiological maturity, root weight, number of pods per plant, unshelled net pod weight, number of cobs per plant, unshelled net cob weight and grain yield) in order to determine their performance. Results obtained revealed that P application levels significantly influenced most of the measured growth and yield parameters of both crops. PAN311 flowered earliest (49 days) across P levels. Increasing P application hastened the maturity of the varieties of PAN 311 and TVu13464 in both seasons. The P levels of 30 and 45 kg/ha reduced the number of days to maturity as compared to 0 and 15 kg/ha. TVu13464 variety produced more pods per plant (30) than other varieties. PAN311 yielded more grains (2491 kg/ha) than other varieties. Maize varieties performed well between P applications of 30 and 45 kg/ha. WE3127 yielded 3462 kg/ha whereas ZM1423 yielded 3306 kg/ha. Intercropping vi system performed better than monocropping system based on the measured growth and yield parameters. Two promising cowpea varieties (PAN311 and TVu13464) performed well and were selected based on their early maturity, drought tolerance and high yielding. Increasing P application levels increased crop yield. Optimum P levels for cowpea-maize strip intercropping were between 30 and 45 kg/ha. The calculated LER values were greater than one which indicates that intercropping was advantageous in land utilisation. The study showed the importance of P application in improving cowpea yield in cowpeamaize strip intercropping. / National Research Foundation (NRF) and University of Missouri, USA
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Vliv stárnutí, ročního období a teploty na práh bolesti u laboratorního potkana / Effect of aging, season and temperature on pain threshold in laboratory rat

Vítková, Jana January 2013 (has links)
Every living creature meets with pain up to these days. Many researches are made in labour conditions, we try to find out how the pain works and how we can suppress it or how we can utilize it in our welfare. Our work is focused on the effect of aging, season, acclimatization and ambient temperature on thermal and mechanic pain threshold in laboratory rats. We were interested how these factors affect the results of the research. Adult male Wistar rats were used in all experiments. Thermal pain thresholds were measured by withdrawal reaction of three body sites: forelimbs, hind limbs and tail. Mechanic pain thresholds were measured by von Frey filaments and a skin temperature was measured by IR thermometer, both of three body sites. Our results demonstrate that : (i) aging have effect on nociceptive pain threshold; (ii) there is presence of cranio-caudal distribution of nociceptive sensitivity in aging and in changing of ambient temperature - forelimbs have lower latency than hind limbs; (iii) thermal pain threshold depends indirectly on ambient and skin temperature; (iv) there was no effect of repeated measurement on nociceptive thresholds of the three body sites; (v) hind limbs and tails are more sensitive to changes of ambient temperature than forepaws; (vi) mechanic pain threshold not change...
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Vybrané diagnostické postupy v průběhu ročního makrocyklu prokazující asymetrie u hráčů florbalu / Selected diagnostic procedures during the annual macrocycle of the floorball season which are used to demonstrate a specific asymmetry in floorbal players

Jelínek, Marian January 2019 (has links)
Title of the thesis: Selected diagnostic procedures during the annual macrocycle of the floorball season which are used to demonstrate a specific asymmetry in floorball players Aims of the thesis: The aim of this work is to identify and analyze the specific time period during the floorball season, which is characteristic with the biggest muscle asymmetry caused due to a specific exercise load that floorball demands. Methods: The research was conducted among elite floorball teams of the top men's floorball competition in the Czech Republic and the tested research group included only male professional athletes. The probands (n = 18 input measurements, n = 10 output measurements) took a total of four complex measurements. Testing was held once before the pre-conditioning period, once during the main course and twice before the playoff. Missing data was supplemented and approximated by the method of multiple imputations in Mplus software. Selected body composition parameters were evaluated, tested and measured on various measuring instruments and machines such as Tanita MC-980MA. The footscan® systems were used to measure postural stability. The explosive force was measured using Kistler force plates and the Cybex Humac Norm isokinetic dynamometer was used to determine the muscle strength of the lower...
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Novel Techniques to Improve Restoration of Native Rangeland Species

Anderson, Rhett Michael 27 March 2020 (has links)
The sagebrush steppe is a particularly sensitive ecosystem that is easily disturbed by fires, oil and gas extraction, woody-plant encroachment, and overgrazing. The natural regeneration of native species following a disturbance within this system is typically slow and sporadic, which allows invasive grasses to occupy the landscape. Attempts to assist the recovery of these landscapes through direct seeding is commonly met with poor success rates, particularly in lower elevation, drier sites. Novel seed enhancement technologies and planting techniques that mitigate limiting factors impairing restoration efforts may improve the likelihood of restoring these degraded areas. For chapter 1, we evaluated a solid-matrix priming technique, where bluebunch wheatgrass (Pseudoroegneria spicata) and Lewis flax (Linum lewisii) were primed and then the priming matrix and seed were pelleted together. We evaluated primed seed that had been incorporated into pellets at two field sites against seed that was pelleted but been left unprimed, and untreated seed (control). These three seed treatments were planted in the spring (mid-march) in shallow (2-cm) and deep (15-cm) furrows, in a complete factorial design. We found that primed seeds generally produced higher plant densities than control seed at the beginning of the growing season; however, its influence diminished towards the end of the growing season. We also found that deep furrows increased plant density throughout the growing season and even into the following year. The combination of priming and deep furrows outperformed control seed in shallow furrows in all measured metrics. For chapter 2, we evaluated a seed conglomeration technique for improving Wyoming big sagebrush (Artemisia tridentata ssp. Wyomingensis) emergence and survival under fall and winter plantings. The trial was implemented at five sites across Utah and Nevada in a randomized complete block-split-split plot design, with site, and planting season, comprising the split-plot factors. Each site and season combination was seeded with conglomerated and control seed. We found that in most cases, a fall seeding of Wyoming big sagebrush was either the same or more successful compared to planting on the snow in the winter, which is the current suggested practice. Our results also demonstrated that seed conglomeration produced higher plant densities compared to control seed throughout the growing season. The higher density of plants produced from conglomerates combined with the improved seed delivery provided by the conglomeration technique was estimated to offset the cost in producing conglomerates and reduce overall restoration costs by 41%.

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