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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.
561

Pollination and evolution of the genus Mystacidium (Orchidaceae)

Luyt, Robyn P. 11 December 2013 (has links)
The morphology, anatomy and pollination biology of Mystacidium Lindl., a small, epiphytic genus of orchids, was investigated within a phylogenetic context. Morphological and anatomical studies were carried out in order to obtain characters for a cladistic analysis of the genus using Cyrtorchis arcuata (Lindl.) Schltr. as an outgroup. The phylogenetic analysis indicated that the genus may not be monophyletic. Two species of the closely related genus Diaphananthe Schltr., D. caffra (H.Bol.) Linder and D. millarii (H.Bol.) Linder, appear to be nested within Mystacidium. Mystacidium species grow in habitats varying from mistbelt forest to dry savanna. Analysis of stable isotope composition (Ȣ¹³C values) of leaves and roots showed that all Mystacidium species, as well as D. caffra and the outgroup C. arcuata, employ CAM photosynthesis. The Ȣ¹³C values were significantly negatively correlated with mean annual rainfall at the collection sites. Breeding system experiments revealed that Mystacidium is dependent on pollinators for fruit set, and that self-pollination results in substantially reduced seed set due to either inbreeding depression or partial self-incompatibility. Field observations revealed that M. venosum Harv. ex Rolfe and M. capense (L.f.) Schltr. are hawkmoth-pollinated, and that M. gracile Harv. and M. pusillum Harv. are pollinated by settling moths. The spurs of the flowers contain dilute, sucrose-dominant nectar. Mystacidium venosum and M. capense showed evidence of nectar reabsorption. Nocturnal emission of scent occurred in all species except M. aliceae H. Bolus and M. brayboniae Summerh., which are unscented, and was composed largely of a combination of monoterpenes and benzoids. Despite substantial variation in spur length (1 - 4.7 cm) among species, no evidence for directional selection on spur length was found in M. venosum, M. capense or M. gracile. Hand pollinations significantly increased fruit set in M. capense in two consecutive seasons at different sites, indicating pollen limitation. Although pollen removal was greater than pollen receipt in M. venosum, M. capense and M. gracile, suggesting transport loss or insufficient visitation, a remarkably high percentage of removed pqllen reached stigmas (35 - 50%). Experiments on M. venosum revealed that flower longevity is reduced by pollination, and that pollinia removed from flowers remained viable for up to 20 days under field conditions. The phylogeny indicated that long-spurred, hawkmoth-pollinated species are basal within the genus, and that shorter-spurred species pollinated by noctuid moths are derived. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2002.
562

Mood Disorders, Personality and Grief in Women and Men undergoing in vitro Fertilization Treatment

Volgsten, Helena January 2009 (has links)
Psychological problems are common in infertile women undergoing in vitro fertilization (IVF) treatment.  The aim of this thesis was to determine the prevalence of psychiatric disorders, such as mood and anxiety disorders, and related risk factors and personality traits in women and men undergoing IVF. Participants were 1090 consecutive women and men, 545 couples, attending a fertility clinic in Sweden during a two-year period. The Primary Care Evaluation of Mental Disorders (PRIME-MD), based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), was used for evaluating mood and anxiety disorders. The participation rate was 862 (79 %) subjects. Any psychiatric disorder was present in 31 % of females and in 10 % of males. Major depression was prevalent in 11 % of females and 5 % of males. Only 21 % of the subjects with a psychiatric disorder had some form of treatment. A negative pregnancy test and obesity (BMI ≥ 30) were risk factors for mood disorders in women and the only risk factor for depression in men was unexplained infertility. Anxiety disorders were less common than in the general population and no IVF-related risk factors were identified. The Swedish universities Scales of Personality (SSP), a self-rating questionnaire, was used for evaluation of personality traits. High scores of personality traits related to neuroticism were associated with mood and/or anxiety disorders among both women and men. Another objective was to explore the experience of childlessness three years after unsuccessful IVF by a qualitative-approach, assessing data by interviews. Failure after IVF was experienced by women in terms of grief, whereas men took upon themselves a supportive role not expressing grief. A need for professional support and counselling in how to handle grief was described. An unstructured end after IVF treatment left unanswered questions. Three years after the end of treatment, men and women were still processing and had not adapted to childlessness, indicating the grieving process was unresolved.
563

Kultūrų prieaugio ir dirvožemio taršos dėl tręšimo augalininkystės ūkyje įvertinimas / Cultural growth and soil fertilization on crop farm assessment

Gaspariūnienė, Justina 17 July 2014 (has links)
Literatūros šaltiniuose pastaruoju metu teigiama, kad siekiant pasiekti optimaliausią derliaus kiekį žemės ūkyje yra naudojama labai dideli kiekiai ir įvairumas trąšų ir kad taip yra alinamas dirvožemio ariamasis sluoksnis. Todėl magistro darbe iškeltas tikslas yra įvertinti tręšimo įtaką dirvožemio taršai bei trąšų efektyvumą kultūrų prieaugiui agrocenozėse, išanalizuojant žemės ūkio normatyvus. / Literary sources have been stating recently that in order to achieve an optimum harvest quantity huge amounts of fertilisers and their variety are used in agriculture and thus the arable layer of the soil is impoverished. As a result, the objective set in the Master‘s Thesis is to evaluate the influence of fertilisation on contamination of the soil and fertiliser efficiency in respect of crop growth in agrocenoses by performing the analysis of the agricultural norms.
564

Dirbtinio apvaisinimo teisinio reglamantavimo problematika Lietuvoje / Artificial fertilization: issues of legal regulation in Lithuania

Cemnolonskis, Kęstutis 02 January 2007 (has links)
Many discussions on the legal regulation of artificial fertilization are taking place in Lithuania though consensus is not yet achieved. Services of assisted reproduction cause fierce scientific, ethical, legal, and religious disputes in Lithuania and elsewhere. It is important to emphasize that legalization of in vitro fertilization at the international as well as national levels is not going to solve the problem. To do this, it is necessary to plan a mechanism of the implementation of the law which would cover many spheres of the legal regulation. The major problem becomes the shortage of scientific studies on legal regulation of artificial fertilization in Lithuania and the rest of the world. The author analyzes the issues of legal regulation of artificial fertilization in Lithuania providing a theoretical model of regulation of the procedure and implementation of the law. The analytical part of the study includes an analysis of the existing bills on artificial fertilization which reveals that both the first and the alternative bills are not quite finished yet and require improvement. Nevertheless the regulation scheme and the content of the Project IXP – 1966(2)A satisfy the main scientific paradigms defined in the theoretical part of the thesis.
565

Evaluation of gamete dysfunction as a cause of failed human in vitro fertilization

Esterhuizen, Aletta Dorothea 12 1900 (has links)
Thesis (D.Phil.)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Chapter 1 provides literature based background information on the clinical importance of sperm morphology as recorded by strict criteria during the diagnostic approach of the infertile couple. Furthermore, the use of a sequential diagnostic schedule for couples in an assisted reproductive programme is emphasized. The author revisited the literature on chromatin packaging of spermatozoa and addresses this issue as an additional semen parameter providing information relating to DNA damaged spermatozoa. The chapter also includes evidence underlining the growing need for the implementation of the acrosome reaction as an important contribution to the assisted reproductive programme. Chapter 2 provides detailed descriptions of the material and methods used during the study. Chapter 3 is sub-divided into 5 sections, each of which represents a separate study that was prepared as a scientific paper. The study included 338 couples consulting for infertility treatment at various gynaecologists in Pretoria and Johannesburg. The diagnostic assisted reproductive laboratory support was provided by the Andrology laboratory of Drs du Buisson and partners from Pretoria. In the first study the role of chromatin packaging as an indicator of in vitro fertilization rates, the semen samples from 72 men were used to record their chromatin packaging quality as well as their sperm morphology classification. Significant different percentages CMA3staining (mean±SE) were recorded among the 2 morphology groups, namely 65.9%±3.5 and 44.5%±1.7 (p=0.001). Using cut off values for chromatin packaging established during the first study, the second study utilized semen from 140 men in the in vitro fertilization (IVF) and intracytoplasmic sperm injection programme (ICSI) to analyze for sperm concentration, motility, morphology and chromatin packaging (CMA3).IVF and ICSI data were stratified using 3 basic cut off values for CMA3staining, namely <44%, >44-60% and >60%. The study concluded that results on the chromatin packaging quality of spermatozoa could be used as an additional parameter of sperm quality since it could provide valuable information on decondensation status of a given sperm population. The third study aimed to establish zona pellucida induced acrosome reaction response (ZIAR) among 35 couples with normal and G-pattern sperm morphology and repeated poor fertilization results during assisted reproduction treatment. Interactive dot diagrams, divided patients into 2 groups i.e. ZIAR<15% and ZIAR>15% with mean fertilization rates of 49% and 79%, respectively. The study concluded that the ZIAR test has diagnostic potential, since it can assist the clinician to identify couples that will benefit from ICSI therapy. The forth study revisited the importance of micro-assay for acrosome reaction determinations in a diagnostic andrology laboratory. The micro-assay not only allows the use of a single zona pellucida, but also facilitates the future possibility of using recombinant zona pellucida proteins in a diagnostic test system. The final study in Chapter 3 includes results obtained from 49 couples (172 oocytes) and aimed to evaluate the role of chromatin packaging and sperm morphology during sperm-zona binding, sperm decondensation and the presence of polar bodies among 170 oocytes that failed in vitro fertilization (IVF). Odds ratio analyses indicated that being in the a group with elevated CMA3 staining i.e. >60%, the risk of decondensation failure increases 15.6 fold relative to normal CMA3 staining <44%. Chapter 4 underlines the validity of the sequential diagnostic approach and summarizes the results and value of a multistep diagnostic scheme. The chapter concludes with the recommendation that both chromatin packaging quality and zona pellucida mediation of the acrosome reaction should be part of the diagnostic tools in the assisted reproductive programme. / AFRIKAANSE OPSOMMING: Die literatuuroorsig in Hoofstuk 1 konsentreer in hoofsaak op die kliniese belang van sperm morfologie en die uitbreiding van die diagnostiese toetse en hantering van die egpaar in die reproduktiewe ondersteuningsprogram. Die kromatien pakkingskwaliteit van die spermsel word onderskryf as In belangrike toevoeging tot die diganostiese program, aangesien ONS skade dikwels saam met kromatiendefekte aangetref word. Die rol van die akrosoomreaksie word ook in detail literatuuroorsigtelik beklemtoon. Hoofstuk 2 bevat volledige inligting omtrent materiaal en metodes wat in die studie gebruik is. Hoofstuk 3 bevat die eksperimentele gegewens wat in 5 afsonderlike sub-afdelings as wetenskaplike publikasies aangebied word. Die studies bestaan uit data van 338 pasiënte, wat deur verskillende ginekoloë van Pretoria en Johannesburg gekonsulteer is waartydens drs. du Boisson en vennote van Pretoria die diagnostiese reproduktiewe laboratoriumdienste verskaf het. Die eerste studie stel dit ten doel om die belang en korrelasie van die spermsel kromatienpakkingskwaliteit van 72 mans te vergelyk met die morfologiese bou van sie sel. Aangesien morfologie reeds gevertig is as 'n kliniese voorspeller van bevrugting was dit nodig om hierdie parameter te vergelyk met die kromatienpakking van die sel. Twee afsnypunte word vir die normo-en teratozoospermiese mans identifiseer naamlik, 44.5%±1.7 en 65.9%±3.5 (p=O.001),respektiewelik. Die tweede studie gebruik die afsnypunte 44% en 66% om die in vitro bevrugting en intrasellulêre sperm inspuiting (ICSI) data te ontleed. Die resultate dui aan dat kromatienpakking In waardevolle bydrae tot die diagnostiek van die pasiënte lewer. Die derde studie stel dit ten doelom die waarde van die zona pellucida geinduseerde akrosoomreaksie (ZIAR) te bepaal. Die studie sluit die data van 35 egpare in wat almal normale of G-patroon morfologie het en verder onverklaarde swak bevrugtings resultate tydens in vitro bevrugtingsterapie. Interaktiewe punt diagram (interactive dot diagrams) verdeel die data in twee groepe naamlik, ZIAR<15% en ZIAR>15% met gemiddelde bevrugtingssyfers van 49% en 79%, respektiewelik. Die studie sluit af met die gedagte dat die ZIAR toets 'n groep pasiënte identifiseer met 'n besondere fisiologiese afwyking d.i. subnormale akrosoom respons op zona pellucida blootstelling. Die vierde afdeling van die hoofstuk onderstreep die belang van die mikro-tegniek vir die bepaling van die akrosoom reaksie, wat tydens die projek gebruik is Die vyfde afdeling van Hoofstuk 3 stel dit ten doelom 170 onbevrugde eierselle van 49 pasiënte te ontleed vir moontlike oorsake vir die mislukte bevrugting. Ondersoeke sluit in die kromatienpakking, sperm-zona binding, sperm dekondensasie en die teenwoordigheid van polêre liggaampies. Statisties blyk dit dat indien 'n kromtienpakking nie normaal is nie (>66%) het die spermsel 'n 15 keer groter kans om nie te dekondenseer nie. Hoofstuk 4 bespreek die noodsaaklikheid van die diagnostiese skedule by die hantering van die onvrugbare egpaar in.
566

A Study On Social And Affective Dimensions Of The Use Of Assisted Reproduction Technology (art) By Women In Turkey

Uner, Ozge 01 September 2004 (has links) (PDF)
This thesis aims to discuss the concept of Assisted Reproduction Technology and its social and affective impacts. Women will be at the center of this research as it has been thought that emotional stressors are mostly effective on them. In the present work, an investigation will be carried out among women who have used assisted reproduction technology methods and women who are able to reproduce and conceive &ldquo / naturally&rdquo / . The comparison of these two groups will illuminate problematical aspects of assisted reproduction technology. The research will be based on two sets of questionnaires designed for each group of women. In this study, both qualitative and quantitative data were used. These analyses will not only lead us to compare infertile and fertile women&rsquo / s responses and evaluate the consequences of emergent assisted reproduction technology but also to assess its social and emotional impacts.
567

Injektionsdüngung

Farack, Katharina, Albert, Erhard 26 May 2011 (has links) (PDF)
Auf drei sächsischen Versuchsstandorten (D, Lö, V) wurde über zwei Jahre die Wirkung der Injektionsdüngung auf Ertrag und Qualität von Winterweizen, Wintergerste und Winterraps untersucht. Nach der Injektion ammoniumhaltiger Düngerlösung in den Boden ist der Stickstoff für die Pflanzen bei Trockenheit besser verfügbar. Das Risiko von Nitratauswaschungen wird vermindert und die Nährstoffe sind weniger erosionsgefährdet. Die Ergebnisse zeigen, dass eine alleinige N-Injektion sowohl zu Winterweizen und Wintergerste als auch zu Winterraps ohne Ertragseinbußen im Vergleich zur praxisüblichen, geteilten Düngung mit Kalkammonsalpeter möglich ist. Zu Ertragsvorteilen führte die Injektionsdüngung besonders nach der ausgeprägten Frühsommertrockenheit 2009 auf dem leichten D-Standort. Landwirte, die auf ihren Flächen die N-Injektion anwenden, bestätigen lt. einer Umfrage gleich hohe bzw. höhere Erträge, gesündere Bestände und einen geringeren Pflanzenschutzmitteleinsatz. Für die Landwirtschaftsbetriebe in Sachsen stellt die Injektionsdüngung eine Möglichkeit dar, die Auswirkungen von Frühsommertrockenheit zu minimieren und die Ertragsstabilität zu verbessern.
568

Wechselwirkung Bodenschutz - Pflanzenschutz - Düngung

Rößler, Iris, Nowack, Anja, Thate, Andela 21 December 2011 (has links) (PDF)
In sächsischen Betrieben wurde bei unterschiedlichen Bodenbearbeitungssystemen die Wechselwirkung zwischen Bodenbearbeitung, Nährstoffversorgung und Pflanzenschutz untersucht. Bei den Bodenbearbeitungssystemen »Pfluglos« und »Konventionell« wurde die Wirkung auf das Nährstoffverhalten im Boden, auf das Nützlingsvorkommen, die Unkrautzusammensetzung und auf pilzliche sowie tierische Schaderreger beurteilt. Es zeigt sich, dass eine zu enge Fruchtfolge die Pflanzenschutzprobleme verschärft. Die Bodenbearbeitung hat entscheidenden Einfluss auf die Artenzusammensetzung, Artenzahl und Unkrautdichte. Das Durchwuchsproblem, eines der Hauptprobleme der nicht wendenden Bodenbearbeitung, mit reduziertem Herbizidaufwand in den Griff zu bekommen, ist nur begrenzt möglich. Im Winterweizen tritt Septoria tritici, DTR und Ährenfusarium bei nicht wendender Bodenbearbeitung mit Vorfrucht Mais oder Stoppelweizen verstärkt auf. Dauerhaft Pfluglos-Flächen der Lössstandorte zeigen einen höheren Gesamt-Behandlungsindex bei Winterweizen. Pfluglose Flächen haben ein höheres Vorkommen an Feldmäusen und Ackerschnecken.
569

Preimplantation diagnosis / Ke-hui Cui

Cui, Ke-hui January 1993 (has links)
Bibliography: leaves 126-147 / xiv, 147 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Summary: Aims to develop reliable procedures for determining the genetic status of embryos derived by IVF procedures prior to implantation. Prenatal diagnosis allows pregnancy to be established using only acceptable embryos / Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 1994
570

Wood and fibre properties of fertilized Norway spruce /

Lundgren, Christina, January 2003 (has links) (PDF)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

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