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Tesi sul tema "Reproduction"
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1
Tang, Shiu-wai. "Reproduction has never been natural the social construction of reproduction in the age of new reproductive technologies /". Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22331888.
Testo completo
2
Clayton, Thompson J. "Law, rights and reproduction : reproductive autonomy in ethical rationalism". Thesis, University of Westminster, 2016. https://westminsterresearch.westminster.ac.uk/item/9y598/law-rights-and-reproduction-reproductive-autonomy-in-ethical-rationalism.
Testo completoAbstract (sommario):
As medical technology has advanced, so too have our attitudes towards the level of control we can expect to hold over our procreative capacities. This creates a multi-dimensional problem for the law in terms of access to services which prevent conception, access to services which terminate a pregnancy and recompensing those whose choices to avoid procreating are frustrated. These developments go to the heart of our perception of autonomy. In order to evaluate these three issues in relation to reproductive autonomy, I set out to investigate how the Gewirthian theory of ethical rationalism can be used to understanding the intersection between law, rights, and autonomy. As such, I assert that it is because of agents’ ability to engage in practical reason that the concept of legal enterprise should be grounded in rationality. Therefore, any attempt to understand notions of autonomy must be based on the categorical imperative derived from the Principle of Generic Consistency (PGC). As a result, I claim that (a) a theory of legal rights must be framed around the indirect application of the PGC and (b) a model of autonomy must account for the limitations drawn by the rational exercise of reason. This requires support for institutional policies which genuinely uphold the rights of agents. In so doing, a greater level of respect for and protection of reproductive autonomy is possible. This exhibits the full conceptual metamorphosis of the PGC from a rational moral principle, through an ethical collective principle, a constitutional principle of legal reason, a basis for rights discourse, and to a model of autonomy. Consequently, the law must be reformed to reflect the rights of agents in these situations and develop an approach which demonstrates a meaningful respect of autonomy. I suggest that this requires rights of access to services, rights to reparation and duties on the State to empower productive agency.
3
Singh, Navsharan. "Contesting reproduction, gender, the state and reproductive technologies in India". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0003/NQ37055.pdf.
Testo completo
4
Weis, Christina Corinna. "Reproductive migrations : surrogacy workers and stratified reproduction in St Petersburg". Thesis, De Montfort University, 2017. http://hdl.handle.net/2086/15036.
Testo completoAbstract (sommario):
Surrogacy is an arrangement whereby a woman conceives in order to give birth to child or children for another individual or couple to raise. This thesis explores how commercial gestational surrogacy is culturally framed and socially organised in Russia and investigates the roles of the key actors. In particular it explores the experiences of surrogacy workers, including those who migrate or commute long distances within and to Russia for surrogacy work and the significance of their origin, citizenship, ethnicity and religion in shaping their experience. Ethnographic fieldwork was carried out in St Petersburg between August 2014 and May 2015 and involved semi-structured interviews, (participant) observations, informal conversations and ethnographic fieldnotes with 33 surrogacy workers, 7 client parents, 15 agency staff and 11 medical staff in medical and surrogacy agency facilities. Data were analysed using inductive ethnographic principles. A reflexive account, which includes a consideration of the utility of making one’s own emotional responses a research tool, is also included. Drawing on and expanding on Colen’s (1995) conceptual framework of stratified reproduction and Crenshaw’s (1989) analytical framework of intersectionality, this research shows that surrogacy in Russia is culturally framed and therefore socially organised as an economic exchange, which gives rise to and reinforces different forms of intersecting reproductive stratifications. These stratifications include biological, social, geographic, geo-political and ethnic dimensions. Of particular novelty is the extension of Colen’s framework to address geographic and geo political stratifications. This was based on the finding that some women (temporarily) migrate or commute (over long distances) to work as gestational carriers. The thesis also demonstrates how an economic framing of surrogacy induced surrogacy workers to understand surrogacy gestation as work, which influenced their relationships with client parents. Given the rapid global increase in the use of surrogacy and its increasingly internationalised nature, this research into the social organisation of commercial gestational surrogacy in Russia is timely and has implications for users, medical practitioners and regulators, as well as researchers concerned with (cross-border) surrogacy and reproductive justice.
5
Mills, Lesley Judith. "Effects of endocrine-disrupting chemicals on fish reproduction and reproductive indicators /". View online ; access limited to URI, 2006. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3248238.
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6
Townsend, Gabrielle. "Proust's imaginary museum : reproductions and reproduction in À la recherche du temps perdu /". Oxford ; Bern Berlin Bruxelles Frankfurt, M. New York, NY Wien : Lang, 2008. http://d-nb.info/987951734/04.
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7
Townsend, Gabrielle. "Proust's imaginary museum : reproductions and reproduction in AÌ€ la recherche du temps perdu". Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419119.
Testo completo
8
Habayeb, Osama. "Cannabinoids and reproduction". Thesis, University of Leicester, 2009. http://hdl.handle.net/2381/29866.
Testo completoAbstract (sommario):
The success of implantation depends on the synchronous development of the embryo and the endometrium. This process is recognised to be regulated by the endocannabinoid system, the most widely studied of which is anandamide.;The first part of this study was the development of a robust assay to measure anandamide in human plasma. The assay was then applied to measure anandamide concentrations during the menstrual cycle, pregnancy, labour and in a group of women presenting with threatened miscarriage. The mean plasma anandamide levels in the follicular phase were 1.68 nM compared to 0.87 in the luteal phase. In pregnancy, the mean levels in the first trimester were 0.89 nM and 0.44 in both the second and third trimesters. At term, the mean levels were 0.68 in the non-labour group and to 2.5 nM in labour. In the threatened miscarriage group, anandamide levels >2.0 nM were predictive of subsequent miscarriage with sensitivity of 100%, specificity of 94.4%, negative predictive value of 100% and positive predictive value of 81.8%.;Finally, to try and identify potential targets of anandamide action, the expression of the cannabinoid receptors (CB1 & CB2) and the enzyme FAAH was studied in first trimester placentas. All proteins studied were present in the tissues examined with the expression of the CB1 diminishing after 9 weeks and FAAH disappearing by 11 weeks gestation. Similarly, anandamide inhibited the growth of BeWo cells in culture. Taken together, these findings suggest that anandamide plays a role in the maintenance of early pregnancy.
9
Fazi, Filippo Maria. "Sound field reproduction". Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/158639/.
Testo completoAbstract (sommario):
This thesis is concerned with the problem of reproducing a desired sound field with an array of loudspeakers. A theory based on functional analysis and the theory of integral equations is developed for the study of this problem. An attempt is made to develop a mathematical framework that can be adopted as a generalized theory of sound field reproduction. The reproduction problem is formulated as an acoustical inverse problem, in which the target sound field is given on the boundary of a control volume located in the interior of the loudspeaker array, while the loudspeaker signals required for the reproduction of the desired field are to be determined. The loudspeaker array is initially modeled as a continuous distribution of secondary sources, mathematically represented by a single layer potential, whose density is to be determined. The singular value decomposition of the integral operator involved is proposed as a method for solving the inverse problem. Closed form expressions are derived for the singular system for the cases of secondary sources arranged on a sphere and on a circle. An attempt is also made to extend the calculation to unbounded geometries, such as an infinite line and a plane. The inverse problem under consideration is in general ill-posed, and the existence and uniqueness of its solution are studied in relation to sound fields of practical interest. It is shown that an exact and unique solution exists for a large family of sound fields. Strategies are proposed for overcoming the problem of nonexistence and nonuniqueness of the solution, arising in cases such as the reproduction of focused sources or when the operating frequency corresponds to one of the Dirichlet eigenvalues of the control region. An important analogy is also drawn between the problem of sound field reproduction and the theory of acoustic scattering. In a later part of this work, the assumptions of a continuous layer of secondary sources and of a single operating frequency are removed, and the resulting consequences are analyzed. The experimental validation of some of the theoretical results is described in the final part of the thesis. A large spherical loudspeaker array is used in an attempt to reproduce the sound field generated by a single virtual source, located in the exterior of the array. Experimental results are in good agreement with the theoretical results over a wide range of frequencies.
10
Lewis, Sophie. "Cyborg labour : exploring surrogacy as gestational work". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/cyborg-labour-exploring-surrogacy-as-gestational-work(2a3f4b10-8a41-4ba9-a193-0a9067babf4a).html.
Testo completoAbstract (sommario):
Commercial gestational surrogacy, also called contract pregnancy, involves privately contracting a biogenetically curated pregnancy using IVF. It distinguishes itself from what is commonly considered 'natural' in procreation, in that the human fetuses it produces are formally entered into a legal unit other than the family of the gestator. My work here contends that this practice is best thought, not in isolation, but in the context of social reproduction more generally and as a central component of future geographies of fetal manufacture that would treat (all) pregnancy as work. This project demands, for me, a critical revisiting of theoretic texts like Mary O'Brien's The Politics of Reproduction (O'Brien 1981). But, in my reading, O'Brien's race-blind gynocentrism doomed her to miss the ensemble of practices - forms of surrogacy among them - that have already long been engaged in the sublation of reproductive labour she professes (yet defers until after the revolution). In geography as in O'Brien, the political horizon of reproductive justice theorised by Black and/or Marxist feminists since the 1970s (Davis 1981; Ross et al. 2016), has been neglected. In assembling materials for a future rewriting of "The Politics of Reproduction" in the context of geography -a trans-inclusive uterine geography- I draw on this canon of reproductive justice first. I question the assumption that there can ever be an absence of surrogacy (i.e. an absence of assistance, co-production, or "sym-poesis" (Haraway 2016)) in babymaking. Thus I explore the synthetic substance of surrogacy synthetically, using a lens I call 'gestational labour': a conceptual hybrid of the postwork perspective on care (Weeks 2011; Federici 1975), the Marxist-feminist concept 'clinical labour' (Cooper and Waldby 2014) and cyborgicity (Haraway 1991). Deploying 'gestational labour' together with a commitment to solidarity vis-à-vis surrogates, I analyse recent events, pro- and anti-surrogacy discourses (both clinical-capitalist and activist), and trends in critical literature that illuminate an immanent 'uterine geography' (or fail to). I aim to demonstrate that the technophobic anticommodification critique of surrogacy's detractors is ultimately as insufficient as the class-blind ('philanthrocapitalist') feminism of surrogacy's sales representatives. My point is that so-called natural forms of the family are themselves already 'technologies of reproductive assistance' differently mediated in the market. Our task is unfortunately neither a matter of simply saying 'stop', nor of pretending that the satisfaction people feel in "mutually advantageous exploitation" (Panitch 2013), on such an unequal playing-field, is somehow 'enough'.Surrogate gestators sometimes show us glimpses of 'mothering against motherhood'. They expose gestation as a cyborg form of labour-power, which is to say, collective human activity always already mixed up with 'technologies' on the one hand and strange more-than-human organisms on the other. Pitting surrogacy against surrogacy, I propose keeping our understanding of what surrogacy could mean radically open. On this basis, I point readers and potential future collaborators towards new kinds of sym-poetic geographical practice: surrogacies - or, engagements with reproductive politics in the broadest sense - which I think our historic moment urgently requires.
11
Wilson, Poe Emma. "Vitrification of day 5/6 human morulas/blastocysts: A 10 year retrospective study in a private assisted reproductive techniques [ART] clinic". Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96876.
Testo completoAbstract (sommario):
Thesis (MMed)--Stellenbosch University, 2015.ENGLISH ABSTRACT: This study was designed to retrospectively evaluate the established embryo vitrification/warming programme currently implemented at Drs Aevitas Institute for Reproductive Medicine and to look at factors that might play a role in optimizing the pregnancy outcomes thereof. Vitrification is the achievement of a “state of suspended animation” wherein molecular translational motions are arrested without structural reorganization of the liquid. In embryo vitrification it involves placement of the embryo in a very small volume of vitrification medium that must be cooled at extremely high cooling rates. The vitrification medium contains cryoprotectants to prevent any cryoinjury from occurring to the embryo. This process was initially proposed to effectively manage supernumerary embryos, but it has also provided a viable method of reducing costs for additional embryo transfers as well as the reduction of the incidence of multiple births. Patients who are at risk of ovarian hyper stimulation syndrome (OHSS) can also have all of their embryos vitrified in advance to reduce the likelihood of adverse clinical symptoms if a pregnancy is established. Throughout the period in which vitrification has been in practice, there have been advances in technology as well as continual research being conducted to establish whether newly suggested techniques do, in fact, optimize the outcomes of vitrification. Focus has subsequently been applied to the carrier device used for vitrification, the day on which the embryos are vitrified and stored, as well as the number of embryos transferred in each respective cycle, all to ensure the most favourable outcome. This retrospective study confirmed the use of the Cryotop® as the most viable carrier device for successful survival and pregnancy outcomes. Transfer of day 5 vitrified embryos resulted in significantly higher pregnancy rates compared to day 6 vitrified embryos. Results also indicated that the number of embryos transferred does indeed have a significant effect on the pregnancy outcome and consequently we can possibly argue against the implementation of single embryo transfer in the vitrification programme. Investigation into the effect of female age, specifically oocyte age, on each of these categories indicated that reduced age can be associated with optimal outcomes; however this could not be proven statistically in this cohort of patients. To further look at optimization of the vitrification/warming programme, a Literature Survey was conducted to ascertain the results after Assisted Hatching in frozen/warmed human embryos. Assisted Hatching has been proposed as a solution to Zona Pellucida hardening, which has been found to occur during vitrification. The need for further studies and a meta-analysis of the literature is confidently proposed, as well as a Prospective Study to evaluate the effect of Laser Assisted Hatching in the human blastocyst vitrification/warming programme at Drs Aevitas Institute for Reproductive Medicine.
AFRIKAANSE OPSOMMING: Hierdie studie is ontwerp om die gevestigde embrio vitrifikasie/ontdooi program by Drs Aevitas Instituut vir Reproduktiewe Medisyne, retrospektief te evalueer en die faktore te optimaliseer wat swangerskap uitkomste kan beïnvloed. Vitrifikasie is die proses waardeur die molekulere aktiwiteit binne die embrio in ‘n staat van arres gehou word sonder om die strukture binne die sitplasma te versteur. Dit behels die plasing van ʼn embrio in 'n klein hoeveelheid vitrifikasie medium wat teen 'n hoë tempo afgekoel word. Die vitrifikasie medium bevat kriobeskermmiddels wat die embrio tydens die vitrifikasie proses teen moontlike skade beskerm. Hierdie proses is aanvanklik voorgestel om oortollige embrio’s doeltreffend te bestuur. Dit bied ʼn koste effektiewe metode vir embrio terugplasing, en verlaag die insidensie van veelvoudige swangerskap. Vitrifikasie bied pasiënte met ʼn hoë risiko vir ovariale hiperstimulasiesindroom (OHSS) ‘n alternatief om nadelige kliniese simptome te vermy indien ʼn swangerskap bereik word. Tegnologiese vordering en voortdurende navorsing ondersoek voortdurend nuwe tegnieke vitrifikasie uitkomste te optimaliseer. Fokus word geplaas op die draertoestel wat gebruik word vir vitrifikasie, die dag waarop die embrio's gevitrifiseer en gestoor word, sowel as die aantal embrio’s wat met elke vitrifikasie siklus teruggeplaas word. Hierdie retrospektiewe studie het bevestig dat die gebruik van die Cryotop® die mees suksesvolle toestel vir oorlewing en swangerskap uitkomste is. Die terugplasing van dag 5 gevitrifiseerde embrios het beduidende hoër swangerskapsyfers as dag 6 embrios tot gevolg gehad. Die resultate het ook aangedui dat die aantal embrio's wat teruggeplaas word 'n beduidende uitwerking op die swangerskapsyfer het. Daar kan dus moontlik teen die implementering van 'n enkel embrio-terugplasing neiging in die vitrifikasie program geargumenteer word. Resultate het ook getoon dat optimale uitkomste verwant is aan ʼn laer oösiet ouderdom, alhoewel dit nie in die groep pasiente statisties bewys kon word nie. 'n Literatuurstudie oor AH (Assisted Hatching) op gevitrifiseerde/ontdooide menslike embrio’s is uitgevoer om die vitrifikasie/ontdooi program verder te optimaliseer. AH bied ‘n oplossing vir Zona pellucida verharding, wat tydens vitrifikasie plaasvind. Verdere studies, 'n meta-analise van die literatuur, sowel as 'n prospektiewe studie om die effek van laser AH in gevitrifiseerde/ontdooide menslike blastosiste by Drs Aevitas Instituut vir reproduktiewe medisyne te evalueer, word voorgestel.
12
Benson, Thomas A. "An evaluation of the relationship between optimum tone reproduction and reproduction size /". Online version of thesis, 1989. http://hdl.handle.net/1850/11550.
Testo completo
13
Wilsher, Sandra Ann. "Studies in equine reproduction". Thesis, University of Bedfordshire, 2009. http://hdl.handle.net/10547/134931.
Testo completoAbstract (sommario):
The papers put forward by the candidate represent a significant contribution to three main areas within the body of knowledge of equine reproduction. Namely, i) epidemiological surveys of the efficiency of Thoroughbred racing and breeding, ii) the morphology and functions of the equine placenta and, iii) embryo transfer in the horse. Two extensive surveys on reproductive efficiency of Thoroughbred mares and stallions at stud and factors associated with the failure of Thoroughbred horses to train and race demonstrated that increasing mare age is the greatest limiting factor to an otherwise high rate of fertility in English Thoroughbreds although a high incidence of early embryonic death remains a significant loss to the breeding industry. The racing wastage survey showed little change over the past 20 years in the percentage of 2- and 3-year-old horses that fail to run, the percentage that are never placed in a race and the number that suffer significant injury or illness during their racing careers. Radical and innovative changes to training methods are needed to overcome these problems. The morphology of the equine placenta was examined using gross measurements, stereological-techniques, vascular casting and immunohistochemistry and the findings related to fetal development and postnatal growth. Stereological measurements applied to term placentae established reference parameters such as surface area per unit volume of placental microcotyledons, the total microscopic area of contact between mother and fetus at the placental interface, and placental VI efficiency. Maternal age, parity, size, genotype and nutrition were all shown to alter placental morphology and, hence, pre- and postnatal fetal development. A novel pair of cervical forceps were designed and marketed to provide a simple and practical method for undertaking transcervical embryo transfer in the horse which enables inexperienced operators to transfer horse embryos successfully. These Wilsher Equine Embryo Transfer Forceps have won widespread acclaim and commercial application in the equine veterinary and scientific communities. A pharmacological method to extend donor-recipient synchrony was developed with both commercial and scientific application. Further work also showed the unique ability of the equine embryo to tolerate a very wide window of donor-recipient asynchrony and it provided a valuable research tool with which to study the relevant roles of the conceptus and uterine environment in regulating embryonic differentiation and fetal growth in the mare.
14
Kirkeby, Ole. "Reproduction of acoustic fields". Thesis, University of Southampton, 1995. https://eprints.soton.ac.uk/65410/.
Testo completo
15
Zeng, Huanzhao. "Preferred skin colour reproduction". Thesis, University of Leeds, 2011. http://etheses.whiterose.ac.uk/2090/.
Testo completoAbstract (sommario):
The memory colour reproduction is an important factor in judging image quality of photographic images of real life scenes. As the most important memory colour category, skin tone was extensively studied for preferred colour reproduction in this research. The methodology to study skin colour preference was then applied to study the colour preference of two other important colour categories: green foliage and blue sky. There are three essential parts for preferred skin colour enhancement: 1) building a skin colour model to detect skin colours or skin pixels; 2) finding a preferred skin colour region or a preferred skin colour centre; and 3) developing an algorithm to morph skin colours toward the preferred skin colour region. This study for skin colour enhancement started with the mathematical modelling of the skin colour region for skin colour detection. The modelling of skin colours was then applied to adjust skin colours of test images for psychophysical experiments that were to determine a preferred skin colour region. Finally, the skin colour modelling and the preferred skin colour centres were applied to adjust skin colours of digital photographic images for preferred colour reproduction. Two approaches were developed to model the skin colour distribution for skin colour detection. The first approach was to model a local colour region for general applications. A convex hull is constructed to fit the geometrical shape of a local region, and then the convex hull is approximated with mathematical formulae. The formulations and data fitting are adjusted with interactive 3-D visualization. The approach is flexible for fitting data gamut with various mathematical forms for different purposes. The other approach was to model skin colours with elliptical shapes. Three elliptical skin colour models were developed for skin colour detection. The first one is to model the skin colour cluster using a single ellipse ignoring the lightness (or luminance) dependency. It is simple and efficient, and the skin colour detection accuracy may be adequate for many applications. In the second model, the skin colour ellipse is adapted to different lightness so that the shape of the ellipse fits the skin colour cluster more accurately. The model is more complex to train and is less efficient in computation, but it is more accurate in skin colour detection. In the third method, an ellipsoid is trained to fit the skin colour cluster. It is almost as simple to train as the first model, but the skin colour detection accuracy is improved. Finally, these models were applied to train mixed skin colours, African skin colours, Caucasian skin colours, and Asian skin colours.
16
Renfree, Marilyn B. "Marsupial reproduction and development". Thesis, Canberra, ACT : The Australian National University, 1988. http://hdl.handle.net/1885/142227.
Testo completo
17
Cherasse, Sarah. "Reproduction and immunity in ant queens: Reproduction et immunité chez les reines de fourmis". Doctoral thesis, Universite Libre de Bruxelles, 2019. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/284596.
Testo completoAbstract (sommario):
Ants and other social Hymenoptera (social bees and wasps) have a remarkable mating strategy. Social Hymenoptera live in societies where reproduction is monopolized by a fertile caste consisting of males and queens. On the other hand, the logistical tasks of the colony are carried out by a sterile female caste known as workers. Reproductive individuals mate during a single bout early in their life and will never engage in additional reproductive events later on. Males die soon after mating while queens store millions of sperm cells in a specialized organ, the spermatheca. Queens will use this sperm stock to fertilize eggs during the rest of their life that can last up to several decades. With a record of 28.5 years in the black garden ant, ant queens have the longest lifespan recorded to date among the social Hymenoptera. In my thesis, I addressed three aspects of ant queen reproduction. First, I tested the effect of mating on the expression of several genes involved namely in fecundity, longevity and immunity. I found that mating induces an up-regulation of the yolk precursor vitellogenin and of the antimicrobial peptide defensin. Second, I measured the intensity of different immune responses in male and queen genital organs in order to determine which immune pathways are activated to protect sperm. Antimicrobial peptide genes are expressed in the genital tract of both sexes and the queen spermatheca is capable of strongly inhibiting bacterial growth. The immune melanization response is, however, overall inactive in the organs tested probably because its unspecific mode of action and cytotoxic by-products are likely to damage sperm cells. Immunity thus seems to be closely regulated in organs that are in contact with sperm. Third, I determined if activation of the queen immune system had an impact on the survival of sperm stored in the spermatheca. There is no detectable effect in young newly mated queens whereas, in one year old queens, immune activation induces a significant reduction in sperm viability. Life stage thus seems to influence queen ability to preserve sperm viability in the event of an immune challenge. In addition, one year old queens have higher sperm viability than newly mated queens suggesting queens are able to displace dead sperm cells from their spermatheca. Finally, I relied on the well-established sequence of behaviors inherent to the early life of ant queens to try to uncover the largely unknown roles of inotocin, the insect ortholog of the vertebrate hormones oxytocin and vasopressin, in regulating insect behavior. I measured gene expression of the inotocin receptor and found that it is highly expressed during social and reproductive behaviors, which is consistent with previous results in vertebrates. Inotocin might thus also be involved in modulating these behaviors in insects, but further studies are needed to be able to fully understand this complex signaling system. Overall, I show that reproduction and immunity are closely linked in ant queens and that the latter provide promising models for investigating the roles of hormones in insects.Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Bashir, Ahmed, e Peter Changufu. "Homosexual Reproduction : An evaluation of the concept of homosexual reproduction in female leadership roles". Thesis, Linnéuniversitetet, Institutionen för organisation och entreprenörskap (OE), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-104344.
Testo completoAbstract (sommario):
In the last few years, the world has seen a relative increase in female leadership in different areas such as political space and the corporate world. This rise has a significant impact on how these female leaders reproduce future leaders of their organizations. This study explores the concept of homosexual reproduction in female leadership roles through their interaction with fellow females in corporate settings. Furthermore, the study was used to determine the factors that prevent homosexual reproduction among female leaders. The study's strategy used a qualitative methodology supported by an inductive approach, empirically with semi-structured interviews to collect data from six experienced female leaders in Sweden and Zambia. Empirical data were analyzed using qualitative analysis of content. The interviews indicate that homosexual reproduction was not present in the female leadership, as most female leaders valued the skills, competency, and qualification. The result also suggests three factors that prevented homosexual reproduction in female leadership roles: competency and qualifications, job profiles, and home and family responsibilities. Female leaders were efficient in their roles because they focused on attaining organizational objectives when thinking about future leaders. The empirical data revealed differences in the barriers that prevented homosexual reproduction in Sweden and Zambia. In Zambia, all the barriers were manifest in the female leaders, while in Sweden, it was only the competency and qualifications aspect.
19
Edwards, Thea M. "Environmental influences on mosquitofish reproduction". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010900.
Testo completo
20
Nyström, Daniel. "Multispectral Color Reproduction Using DLP". Thesis, Linköping University, Department of Science and Technology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1291.
Testo completoAbstract (sommario):
The color gamut, i.e. the range of reproducible colors, is in most conventional display systems not sufficient for accurate color reproduction of highly saturated colors. Any conventional three-primary display suffers from a color gamut limited within the triangle spanned by the primary colors. Even by using purer primaries, enlarging the triangle, there will still be a problem to cover all the perceivable colors. By using a system with more than three primary colors, in printing denoted Hi-Fi color, the gamut will be expanded into a polygon, yielding a larger gamut and better color reproduction.
Digital Light Processing (DLP) is a projection technology developed by Texas Instrument. It uses a chip with an array of thousands of individually controllable micromirrors, each representing a single pixel in the projected image. A lamp illuminates the micromirrors, and by controlling the amount of time each mirror reflect the light, using pulse width modulation, the projected image is created. Color reproduction is achieved by letting the light pass through color filters, corresponding to the three primaries, mounted in a filter wheel.
In this diploma work, the DLP projector InFocus® LP™350 has been evaluated, using the Photo Research® PR®-705 Spectroradiometer. The colorimetric performance of the projector is found to be surprisingly poor, with a color gamut noticeably smaller then that of a CRT monitor using standardized phosphors. This is due to the broad banded filters used, yielding increased brightness at the expense of the pureness of the primaries.
With the intention of evaluating the potential for the DLP technology in multi- primary systems, color filters are selected for additional primary colors. The filters are selected from a set of commercially available filters, the Kodak Wratten filters for science and technology. Used as performance criteria for filter selection is the volume of the gamut in the CIE 1976 (L*u*v*) uniform color space.
The selected filters are measured and evaluated in combination with the projector, verifying the theoretical results from the filter selection process. Colorimetric performance of the system is greatly improved, yielding an expansion of the color gamut in CIE 1976 (L*u*v*) color space by 79%, relative the original three-primary system. These results indicate the potential for DLP in multiprimary display systems, with the capacity to greatly expand the color gamut, by using carefully selected filters for additional primary colors.
21
Björk, Mårten, e Sofia Max. "ARTSY : A Reproduction Transaction System". Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1611.
Testo completoAbstract (sommario):
A Transaction Reproduction System (ARTSY) is a distributed system that enables secure transactions and reproductions of digital content over an insecure network. A field of application is reproductions of visual arts: A print workshop could for example use ARTSY to print a digital image that is located at a remote museum. The purpose of this master thesis project was to propose a specification for ARTSY and to show that it is technically feasible to implement it.
An analysis of the security threats in the ARTSY context was performed and a security model was developed. The security model was approved by a leading computer security expert. The security mechanisms that were chosen for the model were: Asymmetric cryptology, digital signatures, symmetric cryptology and a public key registry. A Software Requirements Specification was developed. It contains extra directives for image reproduction systems but it is possible to use it for an arbitrary type of reproduction system. A prototype of ARTSY was implemented using the Java programming language. The prototype uses XML to manage information and Java RMI to enable remote communication between its components. It was built as a platform independent system and it has been tested and proven to be operational on the Sun Solaris platform as well as the Win32 platform.
22
Chau, Wing-Ki Wilkin. "Colour reproduction for reflective images". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0008/NQ38231.pdf.
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23
Brodin, Thomas. "Ovarian Reserve and Assisted Reproduction". Doctoral thesis, Uppsala universitet, Obstetrik & gynekologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-192998.
Testo completoAbstract (sommario):
Treatment success in IVF-ICSI is mainly limited by female age, but differences in ovarian reserve (OR; the remaining pool of oocytes and their quality) between individuals modify treatment prerequisites among women of similar age. OR may be assessed by OR tests (ORTs). The main aims of this work were to study menstrual cycle length (MCL), basal levels of circulating gonadotrophins, antral follicle count (AFC) and serum Anti-Müllerian hormone (AMH) levels and their associations with and prognostic capacities regarding IVF-ICSI outcome in large cohorts of unselected women. Age-adjusted MCL was positively and linearly associated with pregnancy rates (PRs), live-birth rates (LBRs) and ovarian response to controlled ovarian hyperstimulation. An MCL of >34 days almost doubled the LBR compared with an MCL of <26 days. The grouped variable ‘combined FSH and LH levels’ was superior to both individual gonadotrophin levels and the LH:FSH ratio. The highest mean PR was seen in connection with a combination of FSH <6.7 U/l with LH >4.9 U/l; PRs were lowest when FSH-LH levels were opposite to this (high-low) and intermediate when FSH-LH levels were low-low or high-high. Associations with LBR and ovarian response were similar as those for PR. AFCs and serum AMH levels were positively and log-linearly associated with PR, LBR and ovarian response. Success rates levelled out above AFC 30 or AMH 5 ng/ml. Treatment outcome was superior among women with polycystic ovaries. Among the studied ORTs, logAFC and logAMH concentration correlated most strongly. After multivariate testing, entering all studied ORTs, AMH and female age remained independently associated with LBR. AMH + AFC + age predicted both poor and excessive ovarian responses with high accuracy. Adjusting for age and oocyte yield, all ORTs remained significant for LBR, implying that ORTs also capture information on oocyte quality. In conclusion, measures of OR are strongly associated with PR, LBR and ovarian response in a log-linear fashion, and partly reflect oocyte quality. The OR spectrum is continuous, from small ‘oligofollicular’ ovaries (the low extreme) to polycystic ovaries (the high extreme). Among the studied ORTs, AMH together with age provide the most powerful basal estimate for IVF/ICSI outcome.
24
O'Mahony, Orla Ann. "Angiotensin II in male reproduction". Thesis, Queen Mary, University of London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368852.
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25
Johnson, Mark Richard. "Relaxin and reproduction : an investigation". Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309367.
Testo completo
26
Chen, Cynthia. "Clock genes and female reproduction". Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4149.
Testo completoAbstract (sommario):
The involvement of clock genes in the temporal regulation of the function and lifespan of the corpus luteum (CL) has not been investigated in detail. Immunohistochemistry and real-time quantitative PCR techniques were used to examine the expression of the canonical clock genes: period1, period2, period3, cryptochrome1, cryptochrome2, clock and bmal1, at protein and mRNA levels respectively. The expression of the clock genes was examined in the human CL, cultured luteinised granulosa cells, cultured luteal fibroblast-like cells and the ovine CL. The main findings were that clock genes are expressed in the human and ovine CL; that this expression is manifest at mRNA and protein level in all discernible cell types within the human and ovine CL, and that the pattern of mRNA expression differs between the early luteal phase compared to the late luteal phase. The circadian expression of the clock genes was established in the ovine CL during the late luteal phase and could not be determined in the human CL, although indications from cultured luteinised granulosa cells and luteal fibroblast-like cells suggest that this may also be the case in humans. With the exception of per2, the circadian pattern of clock gene expression emerged in the late luteal phase CL when the early luteal phase CL did not demonstrate circadian clock gene expression. This emergence later in the lifespan of the CL was akin to that observed in embryonic development, where the clock genes are initially non-rhythmic but then acquire circadian rhythmicity with age. In this case, the clock genes have been proposed to perform a non-classical circadian timing role in the timing of embryonic development. The per2 gene was also found to be special, in its loss rather than gain of rhythmic gene expression across the luteal lifespan and in its protein localisation in the cytoplasm of some granulosa-lutein cells. The exceptional behaviour of per2 is consistent with a growing body of evidence supporting its role as a unique clock gene in many respects, able to maintain circadian protein levels in the absence of circadian gene expression, integrating peripheral clock inputs and outputs and acting as a tumour suppressor gene. The CL was also found to be a potential target of melatonin regulation, based on its possession of melatonin MT1 receptors and the timing of circadian cry1 gene expression in the late luteal phase. The expression of cry1 is known to be directly melatonin-induced in the PT and appeared to be similarly activated, downstream of a melatonin signal, in the CL. This supports the evolving view of a hierarchical organisation of the central and peripheral clocks, which are integrated in order to establish information feedback loops that maintain circadian homeostasis, and which can regulate seasonal physiology.
27
McCann, Shaun Adrian. "Narcissism, privatism and social reproduction". Thesis, Nottingham Trent University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341257.
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28
Alam, M. G. S. "Stress and reproduction in cows". Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304744.
Testo completo
29
Humphreys, Natalie J. "Symbiotic bacteria and aphid reproduction". Thesis, University of York, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337631.
Testo completo
30
Skidmore, Julian A. "Reproduction in the dromedary camel". Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339474.
Testo completo
31
Yokokawa, N. "Theories of value and reproduction". Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355285.
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32
De, Haas van Dorsser Florine Juliana. "Reproduction in the Arabian leopard". Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613872.
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33
Hamdan, Mukhri. "Endometriosis and assisted reproduction technology". Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/416621/.
Testo completoAbstract (sommario):
Endometriosis is a disease that is historically known to present in many guises. Since 13th century it has been metaphorically regarded as an animalistic womb causing female hysteria. Albeit widely researched, significant controversies that surround the disease remain unsolved, from the clinical presentations, diagnosis, right through to its management strategies. Despite the rapid advancement of technology in modern medicine, the ideal diagnostic and investigative tool of the disease remains elusive, and hence the management of the disease remains a challenge to clinicians. Whilst it is long known that endometriosis is detrimental to fertility, it is unclear if Assisted Reproductive Technology (ART) obliterates that risk. This thesis aims to investigate the impact of different stages and types of endometriosis on ART outcomes, and how various surgical interventions influence the reproductive outcomes. The thesis will also focus on answering two important questions in endometriosis research, that of whether and how endometriosis impacts on 1) the developing oocytes and embryo, and 2) the endometrium. The thesis begins with the introduction of two robust systematic reviews and meta-analyses, which concluded that women with endometriosis had a lower pregnancy rate and fewer oocytes retrieved during ART. Worse reproductive outcomes were found in those with more severe disease. Surgical treatment, which traditionally is thought to be beneficial, was found to result similar reproductive outcome in diseased and controls, and possibly more harm. Gathering evidence retrospectively from the IVF databases supported the former conclusion that women with endometriosis undertaking ART had lower number of oocytes collected from matured follicles, and further investigation into the laboratory details showed that women with endometriosis had a higher proportion of early embryo arrest. A mouse oocyte model was then utilised to explore the influence of follicular fluid of women with endometriosis on oocyte development. The study found that follicular fluid retrieved from women with endometriosis results in the activation of DNA damage response pathway, which in turn prevented normal oocyte maturation. These effects were found reversed by the agent resveratrol. The thesis concludes with a biomarker discovery study on the endometrium of women with endometriosis compared to controls using a highly sensitive and specific state of the art proteomics analysis method (liquid chromatography mass spectrometry with isobaric tag for relative and absolute quantitation (LCMS/MS iTRAQ®) which uncovered unique proteins not yet described in the literature. Endometriosis is a disease that is detrimental to the reproductive outcomes of those undergoing ART. Its influence on reproduction is complex, but it is now clear that its impact on reproduction does not stop at the traditionally viewed anatomical distortion with resultant subfertility; but have far reaching consequences including that of defective oocyte and embryo development, with a differential impact on the endometrial proteome. The solution to this challenging disease partly lies in the early diagnosis and treatment of the condition; as such not withstanding pitfalls and fallacies surrounding biomarker discovery research, the ultimate validation of a diagnostic panel of biomarkers for the non-invasive diagnosis of endometriosis is now urgently needed.
34
Sprinkle, Jim. "Managing Nutritional Challenges to Reproduction". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/144722.
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35
Giorgis-Allemand, Lise. "Pollution atmosphérique et reproduction humaine". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAS003/document.
Testo completoAbstract (sommario):
Une fraction importante de la population est exposée à la pollution atmosphérique ; ses effets sur la mortalité et la morbidité cardiovasculaire et respiratoire sont connus, et un effet de l'exposition au cours de la grossesse sur le poids de naissance et la croissance fœtale est probable ; un effet sur le risque de naissance prématurée a aussi été suggéré par de nombreuses études, essentiellement en Amérique. En revanche, la capacité des couples à concevoir -fertilité- et les paramètres de la fertilité féminine ont été très peu étudiés en lien avec cette exposition.L’objectif de ce doctorat était de documenter un effet éventuel de la pollution atmosphérique sur la fonction de reproduction humaine et tout particulièrement sur les caractéristiques du cycle menstruel, la probabilité de survenue d’une grossesse (fertilité) et le risque de naissance prématurée.Nous nous sommes appuyés sur une cohorte de couples n’utilisant pas de méthode contraceptive (l’Observatoire de la fertilité en France) et sur treize cohortes de naissances européennes participant au projet ESCAPE (European Study of Cohorts for Air Pollution Effects).Nous avons observé un allongement de la durée de la phase folliculaire du cycle menstruel (période du cycle entre le début des règles et l’ovulation) avec l’exposition de la femme aux particules en suspension dans l’atmosphère (n=158, β=1,6 jour pour une augmentation de la concentration des particules de diamètre aérodynamique inférieur à 10 µm -PM10- de 10 µg/m3 dans le mois précédant le cycle, intervalle de confiance, IC à 95%, 0,3; 2,9). En utilisant deux designs d’étude en parallèle sur la même population, l’approche des durées en cours et l’approche de cohorte prévalente, nous avons mis en évidence une tendance à une diminution de la probabilité de grossesse en association avec l’exposition à la pollution atmosphérique pour la première approche (cohorte prévalente : n=468, risque relatif de grossesse, HR : 0,69 pour une augmentation des PM10 de 10 µg/m3 dans les 70 jours précédant l’inclusion, IC à 95%, 0,43;1,12) ; la tendance était similaire avec l’approche des durées en cours (n=516, durée médiane sans contraception multipliée par 1,29 pour une augmentation des PM10 de 10 µg/m3 dans les 70 jours précédant l’arrêt de la contraception, IC à 95%, 0,97;1,70).Le risque de naissance prématurée, analysé avec un modèle de survie en prenant en compte l’exposition comme une variable dépendant du temps, n’était pas associé à divers polluants atmosphériques dans les cohortes du projet ESCAPE (n=46 791, OR=0,97 pour une augmentation du niveau moyen de PM10 de 10 µg/m3 pendant la grossesse, IC à 95%, 0,87 ;1,07). Nous avons par ailleurs mis en évidence une augmentation du risque de naissance prématurée avec la pression atmosphérique pendant le premier trimestre de grossesse et avec la température moyenne pendant le premier trimestre, au moins dans l’intervalle entre -5°C et 10°C. Nous avons montré qu’une partie de la littérature en faveur d’une association entre particules fines et risque de naissance prématurée pourrait être sujette à un biais causé par des durées de fenêtres d’exposition différentes entre les enfants nés avant terme et ceux nés à terme.Dans l’ensemble, ce travail confirme la nécessité d’utiliser un modèle de survie avec variables dépendant du temps pour étudier le risque de naissance prématurité et appelle à poursuivre les recherches concernant des effets possibles des polluants atmosphériques sur le cycle menstruel et la fertilité, pour lesquels nos travaux font partie des premiers réalisés en population généraleA large fraction of the population is exposed to atmospheric pollution, which has known effects on cardiovascular and respiratory mortality and morbidity and probable effect on birthweight and fetal growth. So far, the biological aptitude to conceive for couples -fecundity- and the female markers of fecundity have been seldom studied in relation with this environmental exposure.The aim of this PhD was to quantify the possible association between atmospheric pollution and specific health outcomes related to human reproduction: menstrual cycle characteristics, probability of pregnancy and preterm birth risk. We relied on a population of couples not using any contraceptive method (Observatory of Fecundity in France) and on 13 birth cohorts participating in the European Study of Cohorts for Air Pollution Effects.We observed that higher levels of atmospheric pollutants during the 30 days before the start of a menstrual cycle were associated with longer follicular phase (n=158, β=1.6 days per each increase by 10 µg/m3 in particulate matters with an aerodynamical diameter of less than 10 µm -PM10; 95% confidence interval: 0.3;2.9). In the population recruited in OBSEFF study, we observed a trend for an increased time to pregnancy with short-term NO2 and PM10 levels in an original approach relying on two seldom used study designs focusing on a marker of fecundity in parallel: the prevalent cohort approach (n=468, hazard ratio of pregnancy, HR: 0.69 per each increase by 10 µg/m3 in PM10 during the 70 days before the inclusion, with a 95% CI of 0.43;1.12) and the current duration approach (n=516, median current duration of unprotected intercourse multiplied by 1.29 per each increase by 10 µg/m3 in PM10 during the 70 days before the contraception stop, 95% CI: 0.97;1.70). In the cohorts included in ESCAPE, preterm delivery risk studied by a survival model with time-dependent exposures was not associated with atmospheric pollutants levels during pregnancy (n=46,791, OR=0.97 per each increase by 10 µg/m3 in PM10 during the whole pregnancy, 95% CI 0.87;1.7). We observed an increased risk of preterm birth with higher atmospheric pressure during the first trimester of pregnancy and to some extent with temperature between -5°C and 10°C during the first trimester of pregnancy. We additionally showed that using exposure windows with different durations between cases and non-cases is a source of a bias in preterm birth studies that may impact several studies in the literature.This work demonstrated that using a survival model with time-dependent exposures is crucial to study preterm delivery risk. It appeals for additional research on the possible adverse effects of atmospheric pollution on menstrual cycle and fecundity, as our studies are among the first ones conducted in a general population on those topics
36
Tinnerholm, Ljungberg Helena. "Omöjliga familjen : Ideologi och fantasi i svensk reproduktionspolitik". Doctoral thesis, Stockholms universitet, Statsvetenskapliga institutionen, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-122219.
Testo completoAbstract (sommario):
The relationship between the state and the people is a central theme in political theory. Discussions in this field have often centered on how a people can come to constitute a state. Less attention, however, has been directed toward the state’s role in constituting and recreating its people. This book examines the Swedish state’s role in forming the people by regulating the use of reproductive techniques: insemination, in vitro fertilization (IVF), and donations of sperm and eggs. The study focuses on how the issue of assisted reproduction was handled and problematized in Swedish policymaking between 1981 and 2005. What problem representations dominated the political debates and decision-making processes surrounding assisted reproduction? How was conflict expressed within the field of reproductive politics (i.e., what aspects caused conflict or political disagreement)? How did collective fantasies play into the political treatment of reproductive technologies? Using historical government and Riksdag material, four major policy debates have been analyzed, from the first legal regulation of assisted reproduction in Sweden in the 1980s up until the inclusion of lesbian couples as beneficiaries of gamete donation. Theoretically, the study is inspired by Ernesto Laclau and Chantal Mouffe’s political discourse theory, Lacanian psychoanalysis, and the “logics approach” developed by Jason Glynos and David Howarth. This combination of perspectives allows for a dual focus on both the form of political articulations and their affective force. Thus, the analysis tries to capture what was taken for granted within the discourse on reproduction (social logics), what arose as points of political conflict or contention (political logics), as well as the affective underpinnings of these social constructions and struggles (fantasmatic logics). The main result of the study is that even though the period saw a quite revolutionary development of new reproductive technologies, the reproduction policies under study took on much more moderate and hesitant character. Throughout the analyzed period there was a more or less consensual view that new reproductive technologies should only be allowed if they did not go against the “child’s best interest.” At the same time, there was significant political conflict over what constituted this interest. Moreover, the reforms that were made never fully embraced the radical implications of the new technologies. Rather, they clung on to previously established patterns of what a “real” family looked like. Thus, every move to allow a new technology or include another category of people as legitimate users of that technology was contingent upon the articulation of a discursive equivalence with previously naturalized methods of reproduction, ultimately taking the heterosexual, nuclear family as an implicit model. Finally, I argue that the production of “sense” in this terrain of radical undecidability was dependent on the mobilization of a series of collective fantasies about “natural life processes,” “nature’s imperfections,” “a humanist view of mankind,” “the stable, original nuclear family”, and so on.
37
Angelier, Frédéric. "Age et reproduction chez les oiseaux marins : mécanismes hormonaux impliqués dans les décisions de reproduction". Poitiers, 2006. http://www.theses.fr/2006POIT2328.
Testo completoAbstract (sommario):
Chez de nombreux organismes, on assiste à une augmentation du succès reproducteur avec l’âge. Cependant, les mécanismes physiologiques impliqués restent mal connus. Ce doctorat a pour objectif d’explorer chez des oiseaux marins l'influence de l'âge sur les mécanismes hormonaux régulant les comportements parentaux, l'allostasie et la réponse au stress (corticostérone et prolactine). Grâce à des suivis démographiques à long terme, nous avons montré que l’âge et l’expérience de reproduction influençaient les taux basaux de ces hormones et la sensibilité au stress. De plus, nous avons décrit les corrélats hormonaux du phénomène de sénescence. Nous avons montré le rôle de la corticostérone, qui régule en interaction avec la condition corporelle, l'effort de recherche alimentaire et les décisions de reproduction. Enfin, nous avons montré que les variations des taux de corticostérone et de prolactine constituaient l'une des causes fonctionnelles de l'influence de l'âge sur le succès reproducteur. Nous discutons de la contribution possible de cette exploration hormonale dans l'origine évolutive des relations entre âge et succès reproducteurBreeding success increases with age in many organisms, but the physiological mechanisms underlying this pattern are poorly known. The aim of this dissertation is to explore the influence of age on hormonal mechanisms involved in the regulation of parental behaviour, allostasis and stress response (corticosterone and prolactin) in seabirds. The use of ongoing long-term mark-recapture programme allowed us to show that age and especially breeding experience influence baseline hormones levels and the sensitivity to stressors. We were able to describe the first hormonal correlates of senescence. We showed the role of corticosterone, which in interaction with body condition, mediates foraging decisions and allocations processes. Our data strongly suggest that variations in baseline corticosterone levels and the ability to maintain a threshold levels of prolactin during a stressful situation may be an important physiological mechanism involved in the improvement of reproductive performance with advancing age. These findings are discussed in the light of current the evolutionary theories addressing the effect of age and experience on reproductive success
38
Larkin, Katelyn. "Effects of polyploidy and reproductive mode on life history trait expression". Thesis, University of Iowa, 2015. https://ir.uiowa.edu/etd/1673.
Testo completoAbstract (sommario):
Although genomes are perhaps the single most important element of living systems, why they feature such striking variation and how this variation is maintained within and across natural populations remains unclear. One of the most common and important means by which genomic variation is generated is ploidy elevation. While polyploidy has been implicated in the remarkably successful radiations of angiosperms, teleost fish, and amphibians, the phenotypic consequences of changes in ploidy level are poorly understood, especially in animals. I use a large, multi-year common garden experiment to identify potential life history costs and benefits of polyploidy and asexual reproduction, a trait often associated with polyploidy, in Potamopyrgus antipodarum. This snail is well suited for studying ploidy variation and sex because diploid sexuals and triploid and tetraploid asexuals frequently coexist, allowing us to use comparisons of sexuals to asexuals and triploid to tetraploid asexuals to study both the effects of ploidy elevation and sex. I detected a strong negative correlation between growth rate and time to maturity and found that sexual P. antipodarum grew and matured significantly more slowly than the polyploid asexuals. Sexual P. antipodarum were also more likely to die before achieving reproductive maturity than their asexual counterparts. By contrast, there were no apparent life history differences between triploid and tetraploid asexuals, indicating that direct phenotypic benefits of ploidy elevation are unlikely to explain the relatively rapid growth and maturation of asexuals. My results suggest that ploidy elevation does not inevitably confer phenotypic consequences, that reproductive mode influences life history trait expression, and that sexual P. antipodarum persist in many natural populations in spite of substantial life history disadvantages.
39
Bjursell, Alice. "Identifying the reproductive state of female Julia Creek dunnarts (Sminthopsis douglasi) by behavioural observations". University of Southern Queensland, Faculty of Sciences, 2006. http://eprints.usq.edu.au/archive/00004243/.
Testo completoAbstract (sommario):
[Abstract]: The Julia Creek dunnart (Sminthopsis douglasi) is an endangered carnivorous marsupial. A recovery plan for the species has been initiated by Queensland Parks and Wildlife Service, which includes captive breeding.An important factor in breeding S. douglasi is the identification of oestrus. The current method to identify oestrus consists of examining urine samplesfor presence of cornified cells. To collect urine, the animals have to be removed from their cages and restrained. This method is stressful for theanimals, as well as time consuming. The aim of this study was to identify specific behaviour of S. douglasi associated with oestrus, which could be readily observed without the need for handling the animal. This wouldprovide a non-invasive way of identifying oestrus, which would facilitate breeding the species in captivity and planning conservation programs.Behaviour of S. douglasi was observed throughout the night by video recording. The most striking result was the increase in activity of the female when she was in oestrus compared to non-oestrus. The most informativebehaviour to observe was entry by the female into the nest box and the frequency with which she entered the area closest to the wall of the enclosure. A discriminant function analysis generated an equation with anover-all predictive power (OPP, the probability of making an accurate identification of reproductive state) of 89%. This result was obtained by watching two random five-minute periods of activity. The equation was tested and verified with new individuals and attained a similar level of OPP. However, the equation was less accurate when the observed female’s social context was changed from being housed adjacent to a male, to being accompanied by another female or housed singularly. Consistent with thesensitivity of activity levels as an indicator, the distance run in an exercise wheel was also a good predictor of oestrous state. Females ran a significantly longer distance in their exercise wheel when in oestruscompared to non-oestrus (p<0.001).
40
Ruhlen, Rachel L. "Diets, estrogen environment of the fetus, and development of the reproductive tract and other systems /". free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3091965.
Testo completo
41
Pollard, Charley-Lea. "Improving mare fertility through dietary intervention: Studies into the effects of nicotinic acid supplementation in vitro and in vivo". Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/27588.
Testo completoAbstract (sommario):
Mare age and reproductive status are thought to be the major drivers of poor reproductive performance, which can result in early embryonic loss rates as high as 20-30%. However, the causes of early embryonic loss are multifactorial and often difficult to establish. Nicotinamide adenine dinucleotide (NAD+) deficiency has recently been implicated in miscarriage and birth defects in women and mice, while NAD+ elevating treatments have resulted in an improvement in oocyte quality from females of advanced maternal age. The aim of this thesis was to investigate the effects of NAD+ precursors on oocyte quality in the mare, opening a potential avenue for improving fertility and reducing early embryo loss in aging mares of high genetic merit. This was achieved through first determining the effects of 3 NAD+ precursors on oocyte quality and embryo development in an appropriate large animal model prior to the determination of the pharmacokinetics of a nicotinic acid supplement in the mare and the ability for the supplement to reach the oocyte in the developing follicle. In order to determine the pharmacokinetics of the NAD+ supplement, an assay for the quantification of various NAD+ metabolites was first developed. This thesis demonstrates that NAD+ biosynthesis is vital to oocyte quality and embryo development in a porcine model, and that nicotinic acid administered as a dietary supplement in mares is rapidly absorbed, metabolised and distributed to cells. Furthermore, supplementation of nicotinic acid over consecutive days of the oestrous cycle in the mare alters the follicular environment in a way that is beneficial for the oocyte. Although further research is needed to fully establish the beneficial effects of NAD+ elevating treatments on oocyte quality and embryo development in the mare, the studies conducted in this thesis have contributed substantially to a more comprehensive understanding of the factors surrounding oocyte quality and early embryonic loss in the mare.
42
Whelan, Shannon. "The Role of Temperature in Timing of Reproduction and Reproductive Success of Gray Jays, Perisoreus canadensis". Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35507.
Testo completoAbstract (sommario):
Although early reproduction within a breeding season often leads to higher reproductive success in seasonal environments, it is still not well understood how reproductive success can be influenced by climate both indirectly through the timing of breeding or by directly altering parental behaviour. In this thesis, I investigate the role of ambient temperature in reproductive success through its effects on the timing of reproduction and brooding in a population of gray jays, Perisoreus canadensis. In chapter 2, I test whether (i) female gray jays adjust laying date in response to temperature, (ii) individual or environmental characteristics constrain this plasticity, and (iii) laying date influences reproductive success. Females laid earlier in warmer years than in colder years; females partnered with older males laid earlier than females partnered with younger males at colder temperatures, but not at warmer temperatures. Early layers were more likely to rear at least one nestling and have a dominant juvenile survive the summer. These findings suggest that male experience could advance female laying date at cold temperatures and subsequently increase the probability of a positive nesting outcome. Though cold temperatures appear to limit timing of reproduction in gray jays, previous work in this system suggests that cold temperatures could better preserve perishable winter food stores. Thus, in chapter 3, I test whether temperatures during early offspring development interact with timing of reproduction to influence reproductive performance. Colder ambient temperatures during incubation were associated with larger brood sizes than warmer temperatures among late breeders, but temperature did not influence brood size among early layers, indicating that costs of late breeding may be amplified by temperatures that are unfavourable for food storage. This thesis contributes to our understanding of the environmental factors that determine reproductive performance, both through effects on timing of reproduction and after eggs are laid.
43
Jackson, Lonnie. "Comparison of color lightness in two-color plus black reproduction system vs. three-color reproduction system /". Online version of thesis, 1987. http://hdl.handle.net/1850/10153.
Testo completo
44
Tang, Shiu-wai, e 鄧紹偉. "Reproduction has never been natural: the social construction of reproduction in the age of new reproductivetechnologies". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31225202.
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45
Chastel, Olivier. "Effort de reproduction chez les oiseaux longevifs : frequence de reproduction et condition physique chez les petrels". Tours, 1995. http://www.theses.fr/1995TOUR4002.
Testo completoAbstract (sommario):
Ce travail concerne une etude comparee de l'effort de reproduction chez 10 especes de petrels, oiseaux marins longevifs. Ces oiseaux presentant une fecondite tres reduite (ponte d'un seul uf), cette approche comparative s'est focalisee sur la frequence de reproduction. Les resultats obtenus montrent l'existence d'un gradient allant des especes annuelles (cotieres et peu longevives) jusqu'aux especes biennales (generalement pelagiques et tres longevives). Cette etude s'est ensuite concentree sur le determinisme de la frequence de reproduction et en particulier sur l'influence de la condition physique (masse corrigee par un indice de taille). La condition physique semble jouer un role cle dans le declenchement et le succes de la reproduction, en particulier chez les especes pelagiques. La condition physique apparait egalement jouer chez certaines especes, un role regulateur permettant a l'adulte d'ajuster son effort d'approvisionnement en fonction de ses besoins et de ceux du poussin
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Batty, Lynne Patricia. "Assisted Reproductive Technology: The Aotearoa/New Zealand Policy Context: A thesis submitted in fulfilment of the requirements for the degree of Master of Arts in Sociology in the University of Canterbury". Thesis, University of Canterbury. Sociology, 2002. http://hdl.handle.net/10092/912.
Testo completoAbstract (sommario):
The focus of this thesis is the current policy situation in relation to assisted reproductive technologies (ART) in Aotearoa/New Zealand. I explore how government policies (and lack of policy) have shaped access to ART. I also explore the policy initiatives of funding agencies, the National Ethics Committee on Assisted Human Reproduction (NECAHR), managers, healthcare professionals, and interest groups. My investigation into ART policy issues critically examines the various formal mechanisms and policies used to regulate and control ART in Aotearoa/New Zealand. Drawing on my analysis of policy-focused documents and material from in-depth interviews with key actors in the policy debate, I demonstrate how the ad hoc and contingent approach to ART developments, practices, funding, and access has contributed to inconsistent and inequitable access to ART services. I argue that the lack of an ART-specific policy organisation contributes to fragmented, and possibly discriminatory, policy decisions. I examine how the use of restrictive access criteria to manage the increasing demand for publicly funded ART services disadvantages certain groups wishing to use these services. By investigating the influence of rationing strategies on the allocation of resources and regulation of access, I provide some appreciation of the 'messy reality' of policy creation, interpretation, and implementation. I argue that the criteria used to limit access to public ART services obscure the use of social judgements and provider discretion. Likewise, they succeed in limiting publicly funded ART treatments to those who conform most effectively to the normative definition of family. My analysis of the ART policy discourse identifies silences and gaps in relation to specific ART practices, particularly the use of ART by Maori. I highlight the invisibility and marginalisation of Maori within the ART policy debate. After examining the broader issues concerning Maori access to health services, I explore how these may affect Maori using ART services to overcome infertility. I argue that the gathering of information about the utilisation of ART services is crucial for the accurate identification of the needs of Maori. It is also fundamental for effective monitoring of state health policy decisions and outcomes.
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Dagg, Joachim. "Strategies of sexual reproduction in aphids". Doctoral thesis, [S.l.] : [s.n.], 2002. http://webdoc.sub.gwdg.de/diss/2002/dagg/dagg.pdf.
Testo completo
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Enoksson, Emmi. "Toward better image reproduction in offset". Doctoral thesis, KTH, Medieteknik och grafisk produktion, Media, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12432.
Testo completoAbstract (sommario):
This thesis has focused on color reproduction processes in the graphics field and is based on theoretical research and practical studies. The purpose of this thesis was to investigate how new tools and tools adapted to a specific production set-up can be used to raise awareness regarding the quality and workflow of images and image processing for sheet-fed offset within the graphic industry. The work is divided in to the following three study areas with several sub-studies: 1) The first research goal of the thesis is to identify knowledge levels regarding color separation of images and demand specifications within printing houses. 2) The second research goal is to investigate whether novel tools and new terminology can help to increase the knowledge level regarding color management 3) The third goal is to investigate whether process specific adaptation of key color control tools can improve quality levels Three surveys about color reproduction (focusing on level of knowledge concerning color separation, the use of ICC-profiles and demand specifications for controlled color reproduction) at printing companies in Sweden were made between 2000 and 2004. The surveys indicated a serious problem in the graphic arts industry, involving both an insufficient understanding of color management and a lack of communication. An important part of the work was to assist in make color management understandable for users and thereby optimize printing. For this purpose, digital test forms have been developed. The developed tools, together with descriptive material, will facilitate the understanding of color management issues. Definitions within the field of color separations have been examined, and changes have been suggested. A new term for separation “Compensation by Black”, CB, has been suggested, instead of e.g. GCR and UCR. Is it possible to adapt the different parts of the process chain in order to achieve an improved production? Yes! This work has developed the method for adaptation of the scanne rtest chart, the printing test chart for image categorization and the control strip forsheet-fed offset using gray balance. This thesis suggests that it is possible to produce a custom-made IT8 target test chart for scanners and achieve a result at least similar to or even better than the standard test charts on the market. This work has also shown that itis possible to adapt the test chart for printing to image category. The result showed that low-key image separated by the image-adapted test chart showed more detail in the dark areas than a low-key image separated by the standard test chart, in the prints on a coated paper. The result from the adaptation of a control strip for sheet-fed offset showed that gray balance can be used as a control parameter for quality control in sheet-fed offset.QC20100617
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Xu, Jiawei. "Analysis of reproduction proteins from butterflies". Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-44404.
Testo completoAbstract (sommario):
Male butterflies have some certain pathways to prevent the female butterfly which has mated with them from mating with other butterflies. Research shows that some proteins from the male butterflies may play an important role in this mechanism. To investigate how the pathway works, the proteins contained in the spermatophore which is injected into the female butterfly by the male one during mating are very important. In this study, the butterfly spermatophore proteins were mainly studied. The proper procedures to obtain the spermatophore from the female body were developed. Since capillary electrophoresis (CE) has many advantages for separation and detection of low amounts of sample, it was used in this study in order to separate the proteins obtained from spermatophores. Finally, Mass Spectrometry (MS) was performed to analyze the proteins after separation in order to identify the proteins. This thesis mainly introduced the following points: 1. The method for obtaining spermatophores from butterfly bodies and the procedures for extracting proteins from spermatophores. 2. Optimized methods and conditions of Capillary Zone Electrophoresis (CZE) for butterfly spermatophore proteins. Several CZE methods and sets of conditions were compared in order to find the optimized ones. 3. Protein samples were applied to Mass Spectrometry (MS) to try to analyze and identify them. Moreover, the effect of using ZiptipsTM for sample pretreatment was discussed.
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Ghuman, Sarvpreet Singh. "Neuroendocrinology of stress and reproduction interaction". Thesis, University of Liverpool, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403220.
Testo completo