Academic literature on the topic 'Transfert de fertilité'
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Journal articles on the topic "Transfert de fertilité":
1
Hours, Armelle. "Éclats de l’affect, éclairs de transfert." Revue française de psychanalyse Vol. 87, no. 5 (November 2, 2023): 1365–70. http://dx.doi.org/10.3917/rfp.875.1365.
Abstract:
À travers une lecture du rapport d’Olivier Bonard, guidée à la fois par la diversité des présentations cliniques et par la fertilité des métaphores, les chemins de l’affect en direction de la théorie seront revisités. À la fulgurance des expressions de l’affect répondent les jaillissements d’une mise en scène, d’une interprétation. Autant d’Einfallen qui initient la possibilité d’une sortie de la sidération qui ne pourra être opérante que dans une autre temporalité que celle de l’urgence. Dans ce travail, l’appui sur la notion des avocats du Ça permet une articulation de la clinique de la séance et de la métapsychologie. Toutefois, le tour de force de Bonard, c’est aussi de montrer via la processualité du travail psychanalytique, que c’est au moment même où, dans un renversement saisissant, le patient se fait avocat du Ça de l’analyste, suite à un acting par exemple, qu’il peut avoir accès à sa propre théorie.
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CHEMINEAU, P., G. BARIL, B. LEBOEUF, M. C. MAUREL, F. ROY, M. PELLICER-RUBIO, B. MALPAUX, and Y. COGNIE. "Implications des progrès récents en physiologie de la reproduction pour la conduite de la reproduction dans l’espèce caprine." INRAE Productions Animales 12, no. 2 (April 30, 1999): 135–46. http://dx.doi.org/10.20870/productions-animales.1999.12.2.3873.
Abstract:
Le contrôle de la reproduction caprine est intéressant pour des raisons techniques (synchronisation des mise bas, ajustements aux disponibilités fourragères ou aux contraintes économiques), et pour des raisons génétiques (identification et dissémination des génotypes améliorateurs). L’utilisation de rythmes photopériodiques accélérés conduit à une augmentation très importante des doses produites pour l’insémination artificielle (IA) et évite l’apparition d’une contre-saison sexuelle. L’identification récente d’une lipase bulbo-uréthrale dans le sperme de bouc offre de nouvelles perspectives pour la conservation de la semence. Chez la chèvre, les traitements " lumière + jours courts " permettent également l’induction de cycles oestriens et ovulatoires à contre-saison, ce qui conduit à une amélioration de la fertilité des troupeaux. En revanche, l’utilisation répétée de eCG (autrefois appelée PMSG) provoque l’apparition d’anticorps, retarde le moment de l’ovulation et induit une baisse de fertilité après IA, lorsqu’elle est réalisée après un délai fixe après la fin du traitement. Toutes les étapes de la production d’embryons, de leur congélation et de leur transfert sont maintenant maîtrisées et permettent d’atteindre des taux satisfaisants de chevreaux nés par femelle donneuse, qui sont compatibles avec le développement de la technique dans le but d’échanger du matériel génétique entre les pays. La production in vitro d’embryons permet des taux élevés de développement après maturation et fécondation in vitro des ovocytes et pourrait permettre l’obtention de populations synchrones de zygotes au stade unicellulaire, nécessaire à l’application des biotechnologies.
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Haras Nationaux, INRA. "Dossier : Actualités en reproduction équine." INRAE Productions Animales 12, no. 5 (July 1, 1999): 331–52. http://dx.doi.org/10.20870/productions-animales.1999.12.5.3901.
Abstract:
La production par une jument d’un poulain par an (et pourquoi pas de plusieurs) avec de la semence d’étalon conservée fraîche ou congelée est l’objectif appliqué actuel de toutes les équipes de recherche. Un point très détaillé en français dans les domaines couverts par notre équipe avait été fait en 1992 dans le Recueil de Médecine vétérinaire (volume 168, numéro 11-12). Depuis, de nouvelles connaissances ou de nouvelles technologies ont vu le jour et il était important de les mettre à disposition d’un large public. Le phénomène d’inactivité ovarienne en début de saison de monte limite le nombre de cycles disponibles pour une fécondation. Des études ont permis d’affiner les conditions des traitements lumineux. Des traitements longs à la mélatonine pourraient permettre de décaler le rythme annuel de reproduction de la jument. Le développement des follicules ovariens est sous le contrôle des hormones hypophysaires FSH et LH, et de facteurs intra-ovariens dont l’inhibine. La maîtrise du nombre d’ovulations permettrait (lors de transfert embryonnaire) de pouvoir produire plusieurs embryons par cycle. Des essais de superovulation sont en cours qui utilisent la FSH exogène ou l’effet anti-inhibine. La maîtrise du moment de l’ovulation peut se faire classiquement par injection d’hCG mais aussi par l’administration de GnRH sous forme d’implant. La croissance et la maturation du follicule dominant, ainsi que l’atrésie des follicules dominés, se caractérisent par l’évolution intrafolliculaire de nombreux paramètres biochimiques dont certains ont été étudiés dans l’espèce équine. Sous échographie transvaginale, le rythme de collecte d’ovocytes le plus rentable est de deux ponctions au cours du même cycle (l’une en fin de croissance folliculaire, l’autre en phase lutéale) : on obtient alors 9 ovocytes en moyenne. La maturation de l’ovocyte provient des maturations respectives du cumulus, du cytoplasme et du noyau. La fécondation in vitro (FIV) n’ayant donné que des résultats moyens, d’autres techniques de reproduction assistée sont utilisées actuellement avec plus de succès au laboratoire : 1) la mise en place de l’ovocyte d’une donneuse soit dans l’oviducte (GIFT), soit dans le follicule (TOIF) d’une receveuse, avec fécondation de la receveuse et 2) l’introduction d’un spermatozoïde directement dans le cytoplasme de l’ovocyte (ICSI). Le transfert d’embryon est utilisé sur le terrain en France principalement pour des juments de haute valeur génétique. Le transport d’embryons frais, mais surtout l’utilisation de la congélation des embryons, simplifieront la gestion entre donneuse et receveuse. La baisse de fertilité observée sur les étalons de plus de 15 ans est fréquemment associée à un profil hormonal caractéristique (niveau basal de FSH et de LH élevé, d’oestrogène diminué, niveau de testostérone non modifié après induction à l’hCG). Ceci pourrait être la conséquence d’une dégénérescence testiculaire primaire. L’évolution des travaux sur la conservation de la semence a abouti à la mise au point de deux grands types de techniques d’insémination : en semence fraîche et en semence congelée. Les résultats obtenus dans les Haras Nationaux montrent que la fertilité par cycle est proche pour les deux types de technique. L’effort doit porter en partie sur des améliorations techniques qui permettront d’avoir accès à toutes les techniques de conservation et d’insémination artificielle pour la grande majorité des étalons. Les critères d’évaluation de la qualité de la semence utilisés en routine (examen de la mobilité essentiellement) ne donnent pas entièrement satisfaction puisqu’ils ne permettent pas de "détecter" certains étalons dont la fertilité se révèle réduite. La plupart des fonctions cellulaires des spermatozoïdes peuvent être explorées : intégrité des membranes, de l’acrosome, stabilité de la chromatine, activité des mitochondries... Cependant les relations de ces fonctions entre elles et, surtout, les relations entre ces fonctions et la fertilité ne sont pas encore très claires.
4
Friedlander, Hilary, Jennifer K. Blakemore, David H. McCulloh, and M. Elizabeth Fino. "Fertility-Sparing Treatment and Assisted Reproductive Technology in Patients with Endometrial Carcinoma and Endometrial Hyperplasia: Pregnancy Outcomes after Embryo Transfer." Cancers 15, no. 7 (April 2, 2023): 2123. http://dx.doi.org/10.3390/cancers15072123.
Abstract:
The goal of fertility-sparing treatment (FST) for patients desiring future fertility with EMCA, and its precursor EH, is to clear the affected tissue and revert to normal endometrial function. Approximately 15% of patients treated with FST will have a live birth without the need for assisted reproductive technology (ART). Despite this low number, little information exists on the pregnancy outcomes of patients who utilize ART. The purpose of this study was to evaluate pregnancy outcomes following embryo transfer in patients with EMCA or EH who elected for FST. This retrospective cohort study at a large urban university-affiliated fertility center included all patients who underwent embryo transfer after fertility-sparing treatment for EMCA or EH between January 2003 and December 2018. Primary outcomes included embryo transfer results and a live birth rate (defined as the number of live births per number of transfers). There were 14 patients, three with EMCA and 11 with EH, who met the criteria for inclusion with a combined total of 40 embryo transfers. An analysis of observed outcomes by sub-group, compared to the expected outcomes at our center (patients without EMCA/EH matched for age, embryo transfer type and number, and utilization of PGT-A) showed that patients with EMCA/EH after FST had a significantly lower live birth rate than expected (Z = −5.04, df = 39, p < 0.01). A sub-group analysis of the 14 euploid embryo transfers resulted in a live birth rate of 21.4% compared to an expected rate of 62.8% (Z = −3.32, df = 13, p < 0.001). Among patients with EMCA/EH who required assisted reproductive technology, live birth rates were lower than expected following embryo transfer when compared to patients without EMCA/EH at our center. Further evaluation of the impact of the diagnosis, treatment, and repeated cavity instrumentation for FST is necessary to create an individualized and optimized approach for this unique patient population.
5
Kim, Seongeun, Michèle Tertilt, and Minchul Yum. "Status Externalities in Education and Low Birth Rates in Korea." American Economic Review 114, no. 6 (June 1, 2024): 1576–611. http://dx.doi.org/10.1257/aer.20220583.
Abstract:
South Koreans appear to be preoccupied with their offspring's education and also have the lowest total fertility rate in the world. We propose a novel theory with status externalities and endogenous fertility connecting these facts, motivated by novel empirical evidence on private education spillovers. Using a quantitative model calibrated to Korea, we find that fertility would be 28 percent higher without the externality. We explore the effects of government policy: a pro-natal transfer or an education tax can increase fertility and reduce education spending. An education tax of 22 percent together with moderate pro-natal transfers maximizes the current generation's welfare. (JEL D31, D62, E24, I21, I26, I28, J13, O40)
6
Palshetkar, Rohan, Mayuri More, Nandita Palshetkar, Hrishikesh Pai, Rishma Pai, and Arnav Pai. "Comparison between sequential transfer vs. day 3 and day 5 frozen embryo transfer in IVF patients." International Journal of Reproduction, Contraception, Obstetrics and Gynecology 12, no. 12 (November 28, 2023): 3583–87. http://dx.doi.org/10.18203/2320-1770.ijrcog20233638.
Abstract:
Background: Sequential embryo transfer is when both cleavage-stage embryo is transferred on day 3 and blastocyst is transferred on day 5, sequentially in the same cycle. This has been suggested for increasing embryo implantation rate. Sequential transfer gives benefit of both day 3 as well as day 5 transfer in the same cycle, giving better outcome in patients suffering infertility. This study compares the implantation rates in sequential transfer vs Day 3 and day 5 transfers. Methods: This multi-centric study is a retrospective study conducted over a period of one year at D. Y. Patil Fertility Centre, Navi Mumbai. Total of 432 transfers were conducted in patients, out of which 262 were Day 3 or cleavage stage embryo transfer, 109 were Day 5 or blastocyst embryo transfer and 61 were sequential embryo transfer. Results: Day 3 transfer group had the clinical pregnancy rate of 52.67%, whereas day 5 transfer group had 60.55% of clinical pregnancy positive cases. Sequential embryo transfer had implantation rate of 60.66%, which was slightly higher than day 5 (60.55%) and day 3 (52.67%) implantation rates. Conclusions: Sequential transfer has marginally increased rate of implantation and clinical pregnancy when compared to day 5 and day 3 transfers.
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Johnston, Josephine, Michael K. Gusmano, and Pasquale Patrizio. "In search of real autonomy for fertility patients." Health Economics, Policy and Law 10, no. 3 (June 9, 2014): 243–50. http://dx.doi.org/10.1017/s1744133114000164.
Abstract:
AbstractNearly one in eight infants in the United States is born preterm. A variety of factors are associated with preterm birth, including multiplicity. In the United States fertility treatments are currently associated with high rates of multiplicity, but these rates could be reduced significantly if changes can be made to fertility treatment policy and practice. These include reducing the financial pressure on patients to prioritize pregnancy chances over safety by expanding insurance coverage and altering the way we calculate success rates and insurance benefits so that two consecutive single embryo transfers is equivalent to one double embryo transfer.
8
Stafford-Bell, M. A., and C. M. Copeland. "Surrogacy in Australia: implantation rates have implications for embryo quality and uterine receptivity." Reproduction, Fertility and Development 13, no. 1 (2001): 99. http://dx.doi.org/10.1071/rd00044.
Abstract:
Since the passage, in November 1995, of the ACT Substitute Parents Agreement Act, The Canberra Fertility Centre has added a true gestational carrier pregnancy programme to its established infertility and IVF services. Embryos generated are transferred as frozen–thawed embryos to the carrier in an average of 2.2 embryos per transfer. Between 1 January 1996 and 31 December 1999 the results of 49 frozen embryo transfers to 25 gestational carriers were compared with 849 frozen embryo transfers on a routine IVF programme. In the carrier group, the embryo implantation rate of 13.8% per embryo transferred is double that of an exactly comparable group of patients undergoing routine frozen–thawed embryo transfer on the same IVF programme and considerably higher than those reported in large series of frozen–thawed embryo transfers. Exclusion from the carrier pregnancy programme of patients with incipient ovarian failure results in an implantation rate of 16.7%, a clinical pregnancy rate of 29.0% and a live birth rate of 19.4% per embryo transfer procedure.
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Bedrick, Bronwyn S., Katelin B. Nickel, Joan K. Riley, Tarun Jain, and Emily S. Jungheim. "Association of State Insurance Mandates for Fertility Treatment With Multiple Embryo Transfer After Preimplantation Genetic Testing for Aneuploidy." JAMA Network Open 6, no. 1 (January 27, 2023): e2251739. http://dx.doi.org/10.1001/jamanetworkopen.2022.51739.
Abstract:
ImportanceMultiple gestation is one of the biggest risks after in vitro fertilization (IVF), largely due to multiple embryo transfer (MET). Single embryo transfer (SET) uptake has increased over time and has been attributed to various factors, such as mandated insurance coverage for IVF and preimplantation genetic testing for aneuploidy (PGT-A).ObjectiveTo investigate whether mandates for IVF insurance coverage are associated with decreased use of MET after PGT-A.Design, Setting, and ParticipantsThis cohort study was conducted using data on embryo transfers reported to the Society for Assisted Reproductive Technology between 2014 and 2016. Data were analyzed from January to October 2021.ExposuresState-mandated coverage for fertility treatment and type of cycle transfer performed (PGT-A, untested fresh, and untested frozen).Main Outcomes and MeasuresUse of MET compared with SET, live birth, and live birth of multiples.ResultsThere were 110 843 embryo transfers (mean [SD] patient age, 34.0 [4.5] years; 5520 individuals identified as African American [5.0%], 10 035 as Asian [9.0%], 5425 as Hispanic [4.9%], 45 561 as White [41.1%], and 44 302 as other or unknown race or ethnicity [40.0%]); 17 650 transfers used embryos that underwent PGT-A. Overall, among transferred embryos that had PGT-A, there were 9712 live births (55.0%). The odds of live birth were 70% higher with MET vs SET after frozen embryo transfer with PGT-A (OR, 1.70; 95% CI, 1.61-1.78), but the risk of multiples was 5 times higher (OR, 5.33; 95% CI, 5.22-5.44). The odds of MET in cycles with PGT-A in states with insurance mandates were 24% lower than in states without mandates (OR, 0.76; 95% CI, 0.68-0.85).Conclusions and RelevanceThis study found that despite the promise of using SET with PGT-A, MET after PGT-A was not uncommon. This practice was more common in states without insurance mandates and was associated with a high risk of multiples.
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Fackelmann, K. A. "Germ Cell Transfer Boosts Fertility." Science News 146, no. 22 (November 26, 1994): 356. http://dx.doi.org/10.2307/3978630.
Dissertations / Theses on the topic "Transfert de fertilité":
1
Drouineaud, Véronique. "Rôle de la protéine de transfert des phospholipides (PLTP) dans le système reproductif mâle." Dijon, 2007. http://www.theses.fr/2007DIJOMU10.
Abstract:
La PLTP est un facteur plasmatique capable de transférer des phospholipides entre les lipoprotéines, mais peut aussi échanger d’autres composés amphipathiques tels le cholestérol non estérifié ou la vitamine E. La vitamine E, connue pour son rôle anti-oxydant, est par ailleurs un facteur clé de la fertilité masculine. Les objectifs de ce travail ont donc consisté à rechercher la présence de PLTP et d’identifier son rôle dans le système reproductif mâle. Dans un premier temps, nous avons mis en évidence que la PLTP était présente dans le plasma séminal humain et qu’elle était responsable à 80% de l’activité de transfert des phospholipides dans ce fluide. Dans un deuxième temps, nous avons examiné les conséquences d’un déficit en PLTP sur la fertilité en utilisant un modèle murin déficient en PLTP (KO-PLTP). Le déficit en PLTP n’affecte que la fertilité mâle, se traduisant par une diminution de la mobilité spermatique progressive chez les souris mâles PLTP -/-, associée à une diminution du nombre d’embryons obtenus par fécondation in vitro réalisée avec des spermatozoïdes de souris mâles PLTP -/- (- 60%, p<0. 05) et à une diminution de la fertilité in vivo avec diminution du nombre de nouveaux-nés (- 32%, p<0. 03). La PLTP est exprimée fortement dans l’épididyme des souris sauvages alors qu’une diminution significative du taux d’alpha-tocophérol est observée dans la tête et la queue de l’épididyme des souris PLTP -/- associée à une diminution du contenu des spermatozoïdes en alpha-tocophérol. Ces observations montrent que la PLTP constitue un nouveau facteur clé de la fertilité mâle, peut-être par le biais d’un transfert de la vitamine EPhospholipid transfer protein (PLTP) was first described as a plasma factor that facilitates the exchange of phospholipid species between circulating proteins. In addition, PLTP can bind and transfer several other amphipathic compounds, including unesterified cholesterol, lipopolysaccharides, diacylglycerides and vitamin E. Vitamin E is well-known for its anti-oxidative properties and is a major determinant of male fertility. The aim of the present study was to search for the presence of PLTP and to identify the physiological role of this protein in reproductive biology. First, PLTP was detected in human seminal plasma and accounted for almost 80% of the phospholipid transfer activity present in seminal plasma. Secondly, the effect of PLTP on reproductive biology was investigated through the comparison of wild-type and PLTP-knocked out mice. We show that PLTP deficiency is associated with hypofertility of mouse males but not mouse females. PLTP deficiency tended to reduce sperm motility and accounts for a significant decrease in total number of pups produced over a 2-month breeding period of PLTP knocked out mice (-32%, P<0. 03). In vitroo fertilization rates of wild-type oocytes with spermatozoa from PLTP-deficient males were markedly reduced as compared with those measured with spermatozoa from wild-type males (-60%, P<0. 05). PLTP is highly expressed in epididymis of mouse males, and alpha-tocopherol was significantly less abundant in cauda and caput epididymis of PLTP-deficient mice as compared with wild-type counterparts. These observations suggest that PLTP is a new key factor in male fertility, probably via the transfer of vitamin E
2
Rokia, Sarah. "Contribution à la modélisation des processus d'agrégation et de transfert d'éléments nutritifs dans les Technosols construits à partir de déchets." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0009/document.
Abstract:
La végétalisation d'espaces en zone urbaine nécessite l'utilisation de grandes quantités de ressource naturelle terreuse. Pour préserver cette ressource non renouvelable, le génie pédologique propose une stratégie de construction de Technosols fertiles à partir du recyclage de déchets et sous-produits. Les propriétés des Technosols sont alors fortement influencées par les matériaux technogéniques qui les constituent. La formulation de mélanges performants pour la croissance des végétaux urbains passe par une analyse scientifique préalable. La fertilité des mélanges et leur évolution au cours du temps peuvent être appréciées par l'étude du processus d'agrégation et du transfert d'éléments nutritifs lors des stades précoces de la pédogenèse. Le modèle expérimental de Technosol construit proposé dans la Thèse développe une méthodologie aboutissant à la sélection de 11 matériaux (ballasts, béton, boues de station d'épuration urbaine, briques, compost de boues et de déchets verts, déchets de balayage de rue, déchets de démolition, déchets verts, terres excavées de profondeur, sous produits papetiers) représentatifs des gisements de déchets recensés au niveau européen et compatibles avec la construction de sol fertile. Le potentiel fertile initial de chaque matériau pur et de certaines combinaisons de mélanges a été mesuré. Puis des expériences menées en conditions contrôlées ont permis d'évaluer l'effet de différents facteurs pédogénétiques (e.g. anthropique, climatique et biologique) sur les processus déterminant de la fertilité des Technosols construits. Les résultats indiquent (i) qu'il est possible de construire un Technosol fertile exclusivement à partir de deux ou trois déchets aux propriétés physico-chimiques complémentaires; (ii) que les propriétés des mélanges sélectionnés peuvent être modélisées à partir des propriétés initiales de leurs matériaux parents.(iii) que lors des premiers stades d'évolution pédogénétique des mélanges, des agrégats stables se forment en fonction de la nature et des propriétés des matériaux parents, (iv) que les transferts d'éléments nutritifs sont fortement dépendants de la nature des matières organiques et du procédé de mélange des particules entre elles. La libération d'éléments nutritifs (e.g. phosphore) serait liée à la taille et la quantité des agrégats formés et en corollaire à la mise en place d'une organisation porale. Les connaissances acquises sur le fonctionnement et l'évolution des Technosols construits à partir de déchets apportent des connaissances nouvelles pour le génie pédologique. La méthode de choix de déchets ainsi que le procédé de formulation de mélanges développés dans ces travaux permettent d'obtenir des mélanges voire des sols construits performants par rapport à des usages attendus. Les modèles d'évolution des mélanges permettent de prédire au cours du temps la fertilité physico-chimique des Technosols construits. Dans le cadre du programme SITERRE-ADEME (2010-2015), les résultats acquis constituent des bases incontournables dans le développement d'un outil d'aide à la décision pour les gestionnaires (e.g. collectivités, bureaux d'étude, entreprises) auquel doit être associée une expertise sur la construction de sol pour la production de biomasse végétaleGreening of urban spaces requires large amounts of arable soil which is a non-renewable resource. To preserve this resource, a strategy is proposed to build fertile Technosols from wastes and by-products by pedological engineering. The properties of Technosols are highly influenced by their constitutive technogenic materials. In order To create favourable mixtures of materials for urban plant growth a preliminary scientific analysis is required. The fertility of the mixtures and their evolution can be assessed by the study of the aggregation process and nutrients transfer during the first stage of pedogenesis. An experimental model of constructed Technosol is proposed in this work. From this model a methodology is developed for the selection of eleven constitutive materials (e.g. bricks, compost made of sludge and green waste, concrete, demolition rubble, excavated earth materials, green wastes, paper mill sludge, sewage sludge, street sweeping wastes, track ballast). Each of these materials is representative of wastes deposits listed European wide and they are suitable candidates for the construction of fertile soils. The fertility of each pure material and of selected mixtures has been determined. Thereafter, experiments under controlled conditions enabled to assess the impact of different pedogenesis factors (e.g. anthropogenic, climatic and biological) involved in the definition of the fertility of constructed Technosols. The results demonstrate (i) the feasibility of the formulation of fertile constructed Technosols exclusively with two or three wastes presenting contrasted physico-chemical properties; and (ii) that the properties of selected mixtures can be modelled using the initial properties of their constitutive parent materials ; (iii) that during the first stage of pedogenesis of the mixtures, depending on parent materials nature and properties, stable aggregates can be formed, (iv) that nutrients transfer are highly dependent on organic matter nature and the process of particles mixing. The delivery of nutrients (e.g. phosphorus) seems to be related to the amounts and size of the formed aggregates and, consequently, to the established porosity. The understanding of the functioning and evolution of Technosols constructed with waste materials provides new knowledge for the development of pedological engineering. The methodology of wastes selection and the mixing process developed in this work enables us to propose mixtures and constructed soils favourable to various uses. The evolution models of the mixtures developed in this work allow the prediction of the physico-chemical fertility of constructed Technosols. The results acquired during this thesis are the main basis of a decision support tool for green spaces operators developed in the framework of the research program SITERRE-ADEME (2010-2015). The use of this decision support tool for plant biomass production, has to be associated with an expertise in soil construction
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Demay, Joséphine. "La disponibilité en phosphore des sols pourrait-elle limiter la production de l’agriculture biologique dans un contexte de forte expansion ?" Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0059.
Abstract:
Face aux crises environnementales et climatiques actuelles, les systèmes de production alimentaire doivent être transformés de toute urgence. Parmi les alternatives possibles, l'agriculture biologique est souvent mise en avant. Cependant, la question de savoir si l'expansion à grande échelle de l'agriculture biologique serait limitée par la disponibilité en nutriments des sols reste encore largement débattue. Jusqu'à présent, des études ont montré qu'à condition de réorganiser en profondeur les systèmes alimentaires, la conversion de 60 % des terres arables à l'agriculture biologique pourrait répondre à la demande alimentaire mondiale. Ces réorganisations incluent une réduction des densités d’animaux et du gaspillage alimentaire, la modification des régimes alimentaires et la relocalisation des élevages et des cultures sur les territoires. Au-delà de ce seuil de 60%, l'azote (N) entrainerait une limitation trop important de la production alimentaire mondiale. Toutefois, ces études n'ont pas examiné si la disponibilité en phosphore (P) des sols pourrait limiter la production de l’agriculture biologique à long terme. Cette question se pose dans la mesure où les engrais minéraux phosphatés, qui contribuent actuellement à plus de la moitié des apports mondiaux de P sur les sols agricoles, sont interdits dans le cadre de l'agriculture biologique. Répondre au manque de connaissances sur ce sujet est primordial, non seulement pour évaluer la capacité de l’agriculture biologique à se développer globalement, mais aussi dans le contexte de l'inévitable épuisement des réserves de roches phosphatées. Dans cette thèse, nous avons tout d'abord quantifié la dépendance de la fertilité actuelle en P des sols agricoles vis-à-vis de l'utilisation passée et présente d'engrais minéraux phosphatés. Nous avons ensuite analysé dans quelle mesure la production de l’agriculture biologique pourrait être affectée par un déficit en P des sols dans un monde 100% biologique. Dans l'ensemble, nous montrons que la fertilité actuelle en P des sols agricoles dépend fortement de l'utilisation cumulée d'engrais minéraux phosphatés sur la période 1950-2017, la moitié du P disponible des sols agricoles mondiaux étant d'origine anthropique. Cette tendance globale cache de fortes disparités entre les pays, reflétant des historiques d’utilisation d'engrais minéraux phosphatés contrastés. La forte dépendance à l'égard des engrais minéraux phosphatés est à la fois une opportunité et un obstacle au développement de l'agriculture biologique. D'une part, elle se traduit souvent par d'importants stocks de P hérités dans les sols, ce qui facilite la transition vers l'agriculture biologique. Cependant, cette dépendance remet en question la durabilité à long terme des systèmes agricoles sans aucun apport de P minéral. Nos simulations d'un monde 100% biologique ont révélé que, si la production agricole serait fortement limitée par l'azote à court terme, un déficit en P des sols agricoles sur le long terme affecterait aussi grandement la production alimentaire, en particulier dans les régions où le niveau actuel de fertilité en P des sols est faible, où les niveaux de production sont élevés et où la part de légumineuses dans les rotations est importante. Après 100 ans de production en agriculture biologique, la production alimentaire mondiale serait réduite de 41 %, les déficits en P des sols des terres arables et des prairies permanentes contribuant respectivement à 39 % et 18 % de cette perte. Dans l'ensemble, notre travail apporte de nouvelles connaissances sur les limitations potentielles de la production de l’agriculture biologique par la disponibilité en P des sols agricoles, soulignant les risques à long terme pour la sécurité alimentaire dans un monde 100 % biologique. Enfin, nous discutons des leviers potentiels qui permettraient de limiter la perte de P des sols agricoles, dont notamment le bouclage du cycle du PFaced with the current environmental and climate crises, food production systems urgently need to transform. Among possible alternatives, organic agriculture is often put forward. Yet, it is still under debate whether large scale expansion of organic farming would be limited by nutrient availability. So far, studies have shown that provided a strong redesign of food systems including a reduction in livestock densities and food waste, changes in diets and re-location of crops and livestock, the global food demand could be met by converting up to 60% of cropland areas to organic agriculture. Above this threshold, nitrogen (N) limitations would lead to an unsatisfied demand. However, these studies have not considered whether soil available phosphorus (P) could limit organic food production in the long run. This question arises because mineral P fertilizers, which currently contribute to more than half of global soil P inputs to cropland soils, are banned under organic farming. Filling this knowledge gap is of utmost importance not only to assess the ability of organic farming to expand globally but also in the context of the slow and inevitable depletion of phosphate rock reserves. In this thesis, we first quantified the reliance of current agricultural soil P fertility on past and current use of mineral P fertilisers. We then analysed the extent to which organic food production would be affected by the potential soil P deficits in a hypothetical 100% organic world. Finally, we quantified the N and P fertility transfers between grassland and cropland soils in order to assess their contribution to the total nutrient inputs to cropland soils. To simulate a 100% organic world, we coupled two already published models: the GOANIM model and the GPASOIL model and ran them for 100 years at a spatially explicit resolution. Overall, we show that the current P fertility of agricultural soils is highly reliant on the cumulated use of mineral P fertilizers over the 1950-2017 period, half of the global soil agricultural available P being of anthropic origin. This global pattern hides great discrepancies between countries, reflecting contrasting historical uses of mineral P fertilizers and contrasting soil biogeochemical backgrounds. The strong reliance on mineral P inputs is both an opportunity and an obstacle to the development of organic farming. On the one hand, heavy dependence on mineral P fertilizers often results in large inherited soil P stocks, making it easier to switch to organic farming. However, this reliance questions the long-term sustainability of farming systems without any mineral P inputs. Our simulations of a 100% organic world revealed that while crop production would be strongly limited by N in the short term, long term P limitations would also strongly affect food production, especially in places with initial low level of P fertility, high levels of production and a high share of N-fixing crop in rotations. After 100 years of farming the world organically, global food production would be reduced by 41%, with global cropland and grassland soil P deficit contributing to 39% and 18% of that loss respectively. We also show that under organic farming, fertility transfers from grassland to cropland soils contribute to 13% and 37% of total N and P inputs to cropland soils respectively, making cropland production levels reliant on the fertility of grassland systems. Overall, our work provides novel knowledge on the potential limitations of organic production by agricultural soil available P, highlighting long term risks for food security in a 100% organic world. Finally, we discuss various options for limiting this global soil P deficit, which include better connected livestock and crop production systems to enhance fertility transfers, closing the P cycle by limiting soil erosion and by better recycling of household organic waste and human excreta back to agricultural soils
4
Suharsono. "Effet du gène mitochondrial atp9 non-édité sur la fertilité, chez des plantes transgéniques de nicotiana tabacum." Bordeaux 2, 1993. http://www.theses.fr/1993BOR28256.
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Hernould, Michel. "Etude de l'expression chez des plantes transgéniques, d'un gène mitochondrial non-édité (atp9) : effet sur la fertilité." Bordeaux 2, 1993. http://www.theses.fr/1993BOR28229.
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Bisson, Anne. "Influence de l'organisation spatiale et de la pression d'herbivorie sur les transferts de fertilité et la productivité des systèmes agro-sylvo-pastoraux : approche écologique de questions agronomiques par l'utilisation de modèles mathématiques." Thesis, Montpellier, SupAgro, 2018. http://www.theses.fr/2018NSAM0052.
Abstract:
La durabilité du fonctionnement des agro-écosystèmes et la gestion des services écosystémiques associés représente un des enjeux majeurs des sciences agronomiques et environnementales.Les systèmes agro-sylvo-pastoraux d'Afrique de l'Ouest (SASP-AO), étudiés depuis longtemps par la communauté scientifique, offrent un cas d’étude pertinent. La fertilité de ces agro-écosystèmes repose traditionnellement sur un taux de recyclage des nutriments très élevé au sein de l'agro-écosystème via la pratique de la jachère et des transferts de nutriments par les mouvements du bétail.Les SASP-AO sont soumis à des pressions socioéconomiques et démographiques fortes qui entrainent des modifications de leur organisation spatiotemporelle et des pratiques agricoles, notamment celles relatives à l'élevage.Dans cette thèse, nous nous sommes intéressés à l'impact de ces modifications sur la production végétale et animale à l'échelle de l'agro-écosystème.Nous avons choisi d’étudier les SASP en développant et analysant des modèles mathématiques de type méta-écosystème. Dans chacun des trois modèles proposés, nous avons cherché à représenter un SASP le plus simplement possible, en incluant les mécanismes biogéochimiques les plus importants (croissance des plantes, minéralisation, lessivage, dépositions…) et les pratiques agricoles d’intérêt. L’objectif était à la fois de comprendre comment ces mécanismes interagissent en fonction des pratiques et d’identifier des propriétés émergentes à l'échelle de l'agro-écosystème.Chacun des modèles a été développé pour étudier l'effet d'un nombre limité de pratiques agricoles portant sur l'organisation des composantes spatiales ou sur la connectivité entre les composantes spatiales.Dans la première partie de cette thèse, nous avons étudié l'influence de la structure des SASP-AO sur la production agricole de ces systèmes. Dans le modèle, quatre sous-systèmes interconnectés sont représentés : l’auréole de case, l’auréole de brousse, la savane et le village. Le modèle est de plus saisonnalisé, la dynamique de la saison sèche étant différente de celle de la saison humide. Avec ce modèle, nous avons étudié l’influence de trois leviers : (1) la durée de rotation et la durée des jachères dans les rotations, (2) la proportion de surface allouée aux différentes zones cultivées (case/brousse) de l'agro-écosystème et (3) la présence/absence du bétail dans l'agro-écosystème. Les résultats issus de ces travaux ont mis en évidence les services écosystémiques fournis par la savane, le rôle de du bétail comme « pompe à nutriments » des zones de pâturage vers les zones cultivées et les interactions entre les effets du bétail et les effets de la jachère sur les flux de nutriments. Dans la seconde partie, nous avons utilisé des outils issus de la théorie du contrôle afin de tenir compte de la variabilité dans le temps des pratiques agricoles. Nous avons ainsi montré qu'en faisant varier la pression d'herbivorie de manière adéquate, un gain supplémentaire de production est possible par rapport à une pression d'herbivorie constante pour une même quantité de nutriments transférée des pâturages vers les cultures.Dans la dernière partie de ce travail, l’optimisation multicritère du fonctionnement de l’agro-écosystème permet d’aborder la complexité des objectifs des SASP-AO comme système de production et de prendre en compte la gestion des risques dans ces systèmes. Nos résultats mettent en avant que les compromis entre production végétale et animale sont liés au choix des plantes cultivées. Nos résultats montrent également que les sources extérieures de nutriments permettent d’augmenter les productions, mais que leur efficience diminue quand leur quantité augmente.À l’interface entre écologie et agronomie, et grâce à l’utilisation conjointe d'outils issus d'autres disciplines, ces travaux de modélisation offrent de nouvelles perspectives pour l'optimisation de la production végétale et la gestion de la fertilité dans les SASPThe sustainability of agro-ecosystem functioning and the management of the associated ecosystem services is one of the major challenges of agronomic and environmental sciences. West African agro-sylvo-pastoral systems (WA-ASPS), which have been studied by the scientific community for a long time, offer an interesting case study. Traditionally, the fertility of these agro-ecosystems relies on a very high rate of nutrient recycling within the agro-ecosystem maintained by both fallowing and livestock induced nutrient transfers.Socio-economic and demographic pressures lead to major changes in the spatial and temporal organization of WA-ASPS and in the associated agricultural practices, including those related to livestock. In this thesis, we are interested in the impact of these changes on crop and meat production at the scale of the agro-ecosystem.We chose to study ASPS by developing and analyzing mathematical models using the ecological concept of meta-ecosystems. In each of the three models proposed, we tried to represent the ASPS as simply as possible, by including the key biogeochemical mechanisms (plant growth, mineralization, leaching, deposition...) and the agricultural practices of interest. The aim was both to understand how mechanisms interact according to the practices and to identify emerging properties at the scale of the agro-ecosystem.Each model was developed to study the effect of a limited number of agricultural practices on the organization of spatial components or on the connectivity between spatial components.In the first part of this work, we studied the influence of the structure of the WA-ASPS on the agricultural production of these systems. In the model, four interconnected subsystems are represented: the compound ring, the bush ring, the savanna and the dwellings. The year is decomposed in two seasons: the dry and the rainy seasons, the dynamic of the system being different for each season. With this model, we studied the influence of three driving-forces on the crop production: (1) the rotation duration and duration of fallows within rotations, (2) the proportion of the agro-ecosystem surface allocated to the different cropland areas (compound/bush) and (3) the presence/absence of livestock in the agro-ecosystem. The results of this work highlight the ecosystem services provided by the savanna, the role of livestock as a "nutrient pump" from rangeland to cropland and the interactions between livestock effects and fallow effects on nutrient fluxes. In the second part, we used tools provided by control theory to take into account the variability over time of agricultural practices. We showed that by varying the herbivory pressure over time in an appropriate way, an additional gain in production is possible (compared to the one obtained with a constant herbivory pressure) for the same amount of nutrients transferred from rangelands to croplands.In the last part of this work, the multi-criteria optimization of the functioning of the agro-ecosystem makes it possible to address the complexity of the objectives of WA-ASPS as a production system and to take into account risks management in these systems. Our results highlight that trade-offs between crop and animal production may be linked to the choice of crops. Our results also show that external sources of nutrients can lead to an increase in productions, but that their efficiency decreases as their quantity increases. At the interface between ecology and agronomy, and by using tools from other fields, this modeling work offers new perspectives for optimizing crop production and fertility management in ASPS
7
McGowan, Rebecca. "Aneuploid Embryo Transfer: Clinical Policies and Provider Opinions at U.S. Fertility Clinics." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563527467302174.
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Underhill, Katharine Lynne. "Transfer and cytogenetic analysis of day 4 embryos in PMSGhCG treated prepuberal gilts." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66237.
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Li, Zhuoyang. "Fertility and pregnancy outcomes following fresh versus frozen-thawed embryo transfer in assisted reproductive technology." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20330.
Abstract:
Background and aims: Assisted reproductive technology has provided great hope for millions of infertile couples. In recent years, frozen-thawed embryo transfer has no longer been merely an add-on to the conventional fresh embryo transfer. Transfer of a cryopreserved embryo has contributed to nearly half of the embryo transfer cycles in Australia. The aim of this thesis is to evaluate the fertility and pregnancy outcomes following fresh versus frozen-thawed embryo transfer. Materials and methods: The thesis includes four studies using population-based data extracted from Australian and New Zealand Assisted Reproduction Database and Victorian Assisted Reproductive Treatment Authority. The risks of ectopic pregnancy, small/large for gestational age birth, and cycle-based live birth following frozen-thawed embryo transfer were compared with those of fresh embryo transfer. This thesis also investigated the cumulative live birth rate from one oocyte retrieval following a ‘fresh transfer’ strategy versus a ‘freeze-all’ strategy. Results: Compared with fresh embryo transfer, frozen-thawed embryo transfer was associated with a decreased risk of ectopic pregnancy and small for gestational age birth, but an increased risk of large for gestational age birth. The ‘freeze-all’ strategy resulted in a similar cumulative live birth rate as the ‘fresh transfer’ strategy among high responders (>15 oocytes), but did not benefit normal (10–15 oocytes) and suboptimal responders (<10 oocytes). Vitrification was the preferred cryopreservation method for blastocysts. Conclusion: This thesis provides population-based evidence of fertility and pregnancy outcomes following fresh versus frozen-thawed embryo transfer. This thesis suggests that, from a population perspective, the ‘freeze-all’ strategy may benefit some subgroups of patients, but should not be offered universally.
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Žamac, Jovan. "Education, pensions, and demography /." Uppsala : Department of Economics, Uppsala University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7433.
Books on the topic "Transfert de fertilité":
1
Beine, Michel. International migration, transfers of norms and home country fertility. [Washington, D.C: World Bank, 2009.
2
Nursing, Royal College of, and Royal College of Nursing. Fertility Nurses Group., eds. Performing intra-uterine insemination and embryo transfer: RCN guidance for fertility nurses. London: Royal College of Nursing, 2004.
3
Nursing, Royal College of, and Royal College of Nursing. Fertility Nurses Group., eds. Performing intra-uterine insemination and embryo transfer: RCN guidance for fertility nurses. London: Royal College of Nursing, 2004.
4
McKey, Mphepo, Waddington S. R, Phombeya Henry S. K, Soil Fertility Network for Maize-Based Cropping Systems in Countries of Southern Africa., Bunda College of Agriculture, and International Maize and Wheat Improvement Center. Maize Improvement Program., eds. The dissemination of soil fertility technologies: Proceedings of a workshop held at Mangochi, Malawi, 15 to 17 July 1996. Harare, Zimbabwe: Soil Fertility Network for Maize-Based Cropping Systems in Countries of Southern Africa, 1997.
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Kihara, Job, Dougbedji Fatondji, James W. Jones, Gerrit Hoogenboom, Ramadjita Tabo, and Andre Bationo, eds. Improving Soil Fertility Recommendations in Africa using the Decision Support System for Agrotechnology Transfer (DSSAT). Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-2960-5.
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Kihara, Job. Improving Soil Fertility Recommendations in Africa using the Decision Support System for Agrotechnology Transfer (DSSAT). Dordrecht: Springer Netherlands, 2012.
7
Reinier, de Graaf Symposium (5th 1984 Nijmegen Netherlands). Gamete quality and fertility regulation: Proceedings of the Vth Reinier de Graaf Symposium, Nijmegen, the Netherlands, 23-25 August 1984. Amsterdam: Excerpta Medica, 1985.
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Turiel, Judith Steinberg. Beyond second opinions: Making choices about fertility treatment. Berkeley: University of California Press, 1998.
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Partridge-Brown, Mary. In-vitro fertilization clinics: A North American directory of programs an services. Jefferson, N.C: McFarland & Co., 1993.
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Beine, Michel, Frederic Docquier, and Maurice Schiff. International Migration, Transfers Of Norms And Home Country Fertility. The World Bank, 2009. http://dx.doi.org/10.1596/1813-9450-4925.
Book chapters on the topic "Transfert de fertilité":
1
Wolf, Don P. "Assessment of Human Sperm Fertility Potential." In In Vitro Fertilization and Embryo Transfer, 103–24. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-1005-1_7.
2
Anderson, Katherine S., Anita P. Tamirisa, John M. Csokmay, and James H. Segars. "Frozen Embryo Transfer Outcomes Among Racial and Ethnic Groups." In Ethnic Differences in Fertility and Assisted Reproduction, 131–44. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-7548-4_11.
3
Connolly, M., and T. Arokoyo. "Alleviating fertilizer technology transfer constraints." In Alleviating Soil Fertility Constraints to Increased Crop Production in West Africa, 19–32. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3224-4_3.
4
Dillon, Lisa, Alla Chernenko, Martin Dribe, Sacha Engelhardt, Alain Gagnon, Heidi A. Hanson, Huong Meeks, Luciana Quaranta, Ken R. Smith, and Hélène Vézina. "20. Did Grandmothers Enhance Reproductive Success in Historic Populations?" In Human Evolutionary Demography, 475–502. Cambridge, UK: Open Book Publishers, 2024. http://dx.doi.org/10.11647/obp.0251.20.
Abstract:
Human reproductive success requires both producing children and making investments in the development of offspring. To a large extent these investments are made by the parents of the child, but researchers are now looking beyond the nuclear family to understand how extended kin, notably grandmothers, enhance reproductive success by making transfers to progeny of different kinds. The extent to which kin influence fertility and mortality outcomes may vary across different socio-economic and geographic contexts; as a result, an international comparative framework is used here to sharpen our understanding of the role of kin in reproduction. This chapter assesses the role of grandmothers in fertility outcomes in a comparative historical demographic study based on data from Scandinavia and North America. The individual-level data used are all longitudinal and multigenerational, allowing us to address the impact of maternal and paternal grandmothers on the fertility of their daughters and daughters-in-law. Attending to heterogeneous effects across space and time as well as within-family differences via the use of fixed effects models, we discover broader associations of the paternal grandmother with higher fertility across the four regions. We also find a general fertility advantage associated with the post-reproductive availability or recent death of the maternal grandmother in the four populations. Important variations across regions nevertheless exist in terms of the strength of the association and the importance of the grandmother’s proximity. Our interpretation is that grandmothers were generally associated with high-fertility outcomes, but that the mechanism for this association was co-determined by family configurations, resource allocation and the advent of fertility control.
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First, N. L., E. S. Critser, and J. M. Robl. "Bovine Embryo: Development, Cloning, Sexing and Transfer of Genes." In Immunological Approaches to Contraception and Promotion of Fertility, 375–92. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4684-5140-5_40.
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Gurven, Michael, Hillard Kaplan, Benjamin Trumble, and Jonathan Stieglitz. "30. The Biodemography of Human Health in Contemporary Non-industrial Populations." In Human Evolutionary Demography, 693–714. Cambridge, UK: Open Book Publishers, 2024. http://dx.doi.org/10.11647/obp.0251.30.
Abstract:
The life history of human hunter-gatherers is characterized by an extended post-reproductive lifespan, prolonged juvenile growth, high fertility with multiple dependents and biparental care, and extensive intra- and inter-generational resource and information transfer. Long-term, indepth study of contemporary non-industrial populations offers important glimpses into how these traits operate, and insights into how they may have evolved. The Tsimane Health and Life History Project is a large-scale bio-behavioral study of the human life course designed to help understand the bidirectional connections between life history, health and social behavior in a high fertility, kin-based population lacking amenities of modern urban life. It seeks to document the epidemiology of health and mortality across the lifespan, and to understand how growth and investment, social structure, sharing networks and behavior impact health and aging. It focuses on how pathogen burden influences health and well-being during development and adulthood, and addresses how modernization affects health and sociality. We reflect on the implications of current findings and highlight the need for more joint ethnographic and biomedical studies of subsistence populations to address unresolved questions not only in evolutionary anthropology or biodemography, but in public health, epidemiology, gerontology and medicine.
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Bationo, Andre, Ramadjita Tabo, Job Kihara, Gerrit Hoogenboom, Pierre C. S. Traore, Kenneth J. Boote, and James W. Jones. "Building Capacity for Modeling in Africa." In Improving Soil Fertility Recommendations in Africa using the Decision Support System for Agrotechnology Transfer (DSSAT), 1–7. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-2960-5_1.
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Fosu, Mathias, S. S. Buah, R. A. L. Kanton, and W. A. Agyare. "Modeling Maize Response to Mineral Fertilizer on Silty Clay Loam in the Northern Savanna Zone of Ghana Using DSSAT Model." In Improving Soil Fertility Recommendations in Africa using the Decision Support System for Agrotechnology Transfer (DSSAT), 157–68. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-2960-5_10.
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Bationo, Andre, Job Kihara, and Akin Adesina. "Beyond Biophysical Recommendations: Towards a New Paradigm." In Improving Soil Fertility Recommendations in Africa using the Decision Support System for Agrotechnology Transfer (DSSAT), 169–84. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-2960-5_11.
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Hoogenboom, Gerrit, James W. Jones, Pierre C. S. Traore, and Kenneth J. Boote. "Experiments and Data for Model Evaluation and Application." In Improving Soil Fertility Recommendations in Africa using the Decision Support System for Agrotechnology Transfer (DSSAT), 9–18. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-2960-5_2.
Conference papers on the topic "Transfert de fertilité":
1
Jia, Hai-Yang, Juan Chen, He-Long Yu, and Da-You Liu. "Soil fertility grading with Bayesian Network transfer learning." In 2010 International Conference on Machine Learning and Cybernetics (ICMLC). IEEE, 2010. http://dx.doi.org/10.1109/icmlc.2010.5580915.
2
Miles, A. M., J. L. Hutchison, and P. M. VanRaden. "672. The rising popularity of embryo transfer in U.S. dairy cattle and implications for national fertility evaluations." In World Congress on Genetics Applied to Livestock Production. The Netherlands: Wageningen Academic Publishers, 2022. http://dx.doi.org/10.3920/978-90-8686-940-4_672.
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Okros, Adalbert, Valeria Ciolac, Casiana Mihut, Daniela Scedei, and Carmen Claudia Durau. "EVALUATION OF AGRICULTURAL LAND OUTSIDE THE TOWN OF PERIAM TIMIS COUNTY." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/3.1/s13.29.
Abstract:
The importance of land assessment activity consists in the fact that the data provided by these studies constitute the basic documentation for establishing the most appropriate practical measures for protection, improvement and rational use of soils for biomass production in an optimized and rigorous dynamics. correlated with the growing demands of environmental protection. The evolution and fertility of soils is conditioned by a large number of their individual properties and by many specific processes that take place on the surface or inside them. Of greater importance in this case is the ability to transform and accumulate the soil, its ability to store the substances necessary for the growth and fruiting of plants, characteristics of the soil or from outside. Some of these characteristics that determine soil fertility are relatively stable, difficult to change, but most can be more or less modified by slow but continuous intervention of natural factors or by degrading or improving anthropogenic interventions. According to these precepts, the soil is an indicator of the state of quality and evolution of the environment and can be used in this position to evaluate the efficiency of the works of arrangement, improvement and correct use of the exploitation.
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Minkina, T. M., A. P. Glinushkin, V. P. Kalinitchenko, D. A. Makarenkov, V. E. Zinchenko, V. V. Chernenko, V. V. Chelnokov, et al. "Soil solution calcium carbonate equilibrium as a driver of soil organic matter and heavy metals transfer and turnover in focus of humic substances soil fertility effect." In Fifth International Conference of CIS IHSS on Humic Innovative Technologies «Humic substances and living systems». CLUB PRINT ltd., 2019. http://dx.doi.org/10.36291/hit.2019.minkina.121.
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David, Gheorghe, Dorin Tarau, Alina Agapie, Saida Feier-David, and Cristian Sandor. "THE EVOLUTION OF HYDROPHYSICAL PROPERTIES OF A TYPICAL CERNOZEM, CULTIVATED WITH WHEAT IN THE EXPERIMENTAL CYCLE 2016-2021." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/3.1/s13.39.
Abstract:
The main purpose of the research carried out through 2016-2021, on a chernozem type soil, with remarkable fertility characteristics, located in the lower Plain of Banat, finds its origin in the current scientific discussions and practical preoccupations, which are more and more intense, as it is imperative find and developed an integrated management, which is agronomically efficient, in the current context of global climate change. These represent a major challenge for the agricultural sector, in order to ensure water resources and crop stability, being great priorities in developing policies to prevent and reduce the impact of extreme weather events, which, lately, appear and are manifest a lot more. Under these conditions, the efficient management of extreme meteorological phenomena has a particular importance for the establishment of sustainable plant cultivation technologies, in order to obtain large and profitable agricultural productions. The research was based on the accumulation of scientific data, regarding the development of some agricultural land productivity components, with reference to the cosmic-atmospheric (temperatures, precipitations) and telluric-edaphic offer (hydrophysical properties such as: humidity, useful water capacity, field capacity, wilting coefficient), necessary for the substantiation of some modern culture technologies, capitalizing to the maximum, the physical-geographical as well as the climatic-edaphic conditions, of the lower Plain of Banat from the Western part of Romania. These recurring determinations of soil moisture within the researched area, from a chernozem soil type, cultivated with wheat, as the most important field plant cultivated in our country and in Europe for bread making, are in line with the concerns from the study field, both nationally and globally, as well as in line with the climate changes present in recent decades, through the transfer of knowledge and innovation in agriculture and natural resource risk management. All of the statements mentioned above represent important priorities for the current common agricultural policy of the States Members of the European Union, on medium and long term, regarding the development of the agricultural sector.
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Perminova, Irina. "Humics-Based Chemicals and Materials Designed for Ecoadaptive Chemistry and Technology." In 20TH CONFERENCE OF THE INTERNATIONAL HUMIC SUBSTANCES SOCIETY. Non-Commercial Partnership "Center for Biogenic Resources "Humus Sapiens" (NP CBR "Humus Sapiens"), 2021. http://dx.doi.org/10.36291/ihss.2021.perminova.
Abstract:
Humic substances (HS) are abundant in the environment. They penetrate through water, soil, and air. They have plentiful fossil and renewable resources including oxidized brown coal, peat, sapropel, spent sulphite liquor, composts, and other organic waste. HS govern many vitally important ecosystem processes like maintenance of soil fertility, nutrients delivery to plants, mitigation of abiotic stresses, etc. Numerous examples on their beneficial effects to plants and other living organisms are reported. Still, due to complexity of humic molecular assemblies, they have been very limitedly tapped for practical needs. Here we introduce a concept of ecoadaptive chemistry, which implies molecular and functional studies of life-sustaining processes in nature aimed at their further transfer into ecoadaptive technologies via rational design of nature-like chemicals, materials, and processes (Perminova 2019). We show how the disclosed mechanisms of self-purification and self-healing implied by natural systems can be applied to molecular design of humics-based products (chemicals, materials) with the tailored properties. The examples will be given for direct chemical modification of HS by incorporation of phenolic units into molecular backbone of HS, for preparation of interpolyelectrolyte complexes with aminoorganolanes , for HS assisted synthesis of nanoparticles with the needed properties (iron (hydr)oxides, silver, gold), for preparation of HS-based hybrid nanomaterials. The possibilities for practical applications of the obtained humic derivatives, polyelectrolyte complexes, HS-stabilized nanoparticles and hybrid materials will be demonstrated. They include novel humics-based biocatalytic systems for manipulation of microbial metabolism (suppression of methane synthesis by methanogens), solid HS-clay emulsion stabilizers for eliminating of oil slicks, humics-based non-lactam inhibitors of beta-lactamases, HS-based nanomaterials for wound-healing. The developed approaches open a way for broad innovative applications of humics-based chemicals and materials both in the field of environmental protection, biotechnology, human and environmental health. They also contribute to further elaboration and development of the concept of ecoadaptive chemistry and technology. References Perminova, I.V. From green chemistry and nature-like technologies towards ecoadaptive chemistry and technology. Pure and Applied Chemistry 2019, 91(5), 851-864. DOI: 10.1515/pac2018-1110 Acknowledgement: This research was supported by the Russian Science Foundation 20-63- 47070. The studies were conducted in the framework of the Interdisciplinary Scientific and Educational School of M. V. Lomonosov Moscow State University “Future Planet and Global Environ-mental Change”.
Reports on the topic "Transfert de fertilité":
1
Hansen, Peter J., and Amir Arav. Embryo transfer as a tool for improving fertility of heat-stressed dairy cattle. United States Department of Agriculture, September 2007. http://dx.doi.org/10.32747/2007.7587730.bard.
Abstract:
The overall objective of the current proposal is to develop procedures to improve the pregnancy rate achieved following transfer of fresh or cryopreserved embryos produced in the laboratory into heat-stress recipients. The overall hypothesis is that pregnancy rate in heat-stressed lactating cows can be improved by use of embryo transfer and that additional gains in pregnancy rate can be achieved through development of procedures to cryopreserve embryos, select embryos most likely to establish and maintain pregnancy after transfer, and to enhance embryo competence for post-transfer survival through manipulation of culture conditions. The original specific objectives were to 1) optimize procedures for cryopreservation (Israel/US), 2) develop procedures for identifying embryos with the greatest potential for development and survival using the remote monitoring system called EmbryoGuard (Israel), 3) perform field trials to test the efficacy of cryopreservation and the EmbryoGuard selection system for improving pregnancy rates in heat-stressed, lactating cows (US/Israel), 4) test whether selection of fresh or frozen-thawed blastocysts based on measurement of group II caspase activity is an effective means of increasing survival after cryopreservation and post-transfer pregnancy rate (US), and 5) identify genes in blastocysts induced by insulin-like growth factor-1 (IGF-1) (US). In addition to these objectives, additional work was carried out to determine additional cellular determinants of embryonic resistance to heat shock. There were several major achievements. Results of one experiment indicated that survival of embryos to freezing could be improved by treating embryos with cytochalasin B to disrupt the cytoskeleton. An additional improvement in the efficacy of embryo transfer for achieving pregnancy in heat-stressed cows follows from the finding that IGF-1 can improve post-transfer survival of in vitro produced embryos in the summer but not winter. Expression of several genes in the blastocyst was regulated by IGF-1 including IGF binding protein-3, desmocollin II, Na/K ATPase, Bax, heat shock protein 70 and IGF-1 receptor. These genes are likely candidates 1) for developing assays for selection of embryos for transfer and 2) as marker genes for improving culture conditions for embryo production. The fact that IGF-1 improved survival of embryos in heat-stressed recipients only is consistent with the hypothesis that IGF-1 confers cellular thermotolerance to bovine embryos. Other experiments confirmed this action of IGF-1. One action of IGF-1, the ability to block heat-shock induced apoptosis, was shown to be mediated through activation of the phosphatidylinositol 3-kinase pathway. Other cellular determinants of resistance of embryos to elevated temperature were identified including redox status of the embryo and the ceramide signaling pathway. Developmental changes in embryonic apoptosis responses in response to heat shock were described and found to include alterations in the capacity of the embryo to undergo caspase-9 and caspase-3 activation as well as events downstream from caspase-3 activation. With the exception of IGF-1, other possible treatments to improve pregnancy rate to embryo transfer were not effective including selection of embryos for caspase activity, treatment of recipients with GnRH.and bilateral transfer of twin embryos. In conclusion, accomplishments achieved during the grant period have resulted in methods for improving post-transfer survival of in vitro produced embryos transferred into heat-stressed cows and have lead to additional avenues for research to increase embryo resistance to elevated temperature and improve survival to cryopreservation. In addition, embryo transfer of vitrified IVF embryos increased significantly the pregnancy rate in repeated breeder cows.
2
Daruich, Diego, and Julian Kozlowski. Explaining Intergenerational Mobility: The Role of Fertility and Family Transfers. Federal Reserve Bank of St. Louis, 2018. http://dx.doi.org/10.20955/wp.2018.011.
3
Hansen, Peter J., and Zvi Roth. Use of Oocyte and Embryo Survival Factors to Enhance Fertility of Heat-stressed Dairy Cattle. United States Department of Agriculture, August 2011. http://dx.doi.org/10.32747/2011.7697105.bard.
Abstract:
The overall goal was to identify survival factors that can improve pregnancy success following insemination or embryo transfer in lactating dairy cows exposed to heat stress. First, we demonstrated that oocytes are actually damaged by elevated temperature in the summer. Then we tested two thermoprotective molecules for their effect on oocyte damage caused by heat shock. One molecule, ceramide was not thermoprptective. Another, insulin-like growth factor-1 (IGF) reduced the effects of heat shock on oocyte apoptosis and oocyte cleavage when added during maturation. We also used lactating cows exposed to heat stress to determine whether bovine somatotropin (bST), which increases IGF1 levels in vivo, would improve fertility in summer. Cows treated with bST received a single injection at 3 days before insemination. Controls received no additional treatment. Treatment with bST did not significantly increase the proportion of inseminated cows diagnosed pregnant although it was numerically greater for the bST group (24.2% vs 17.8%, 124–132 cows per group). There was a tendency (p =0.10) for a smaller percent of control cows to have high plasma progesterone concentrations (≥ 1 ng/ml) at Day 7 after insemination than for bST-treated cows (72.6 vs 81.1%). When only cows that were successfully synchronized were considered, the magnitude of the absolute difference in the percentage of inseminated cows that were diagnosed pregnant between bST and control cows was reduced (24.8 vs 22.4% pregnant for bST and control). Results failed to indicate a beneficial effect of bST treatment on fertility of lactating dairy cows. In another experiment, we found a tendency for addition of IGF1 to embryo culture medium to improve embryonic survival after embryo transfer when the experiment was done during heat stress but not when the experiment was done in the absence of heat stress. Another molecule tested, granulocyte-macrophage colony-stimulating factor (GM-CSF; also called colony-stimulating factor-2), improved embryonic survival in the absence of heat stress. We also examined whether heat shock affects the sperm cell. There was no effect of heat shock on sperm apoptosis (programmed cell death) or on sperm fertilizing ability. Therefore, effects of heat shock on sperm function after ejaculation if minimal. However, there were seasonal changes in sperm characteristics that indicates that some of the decrease in dairy cow fertility during the summer in Israel is due to using semen of inferior quality. Semen was collected from five representative bulls throughout the summer (August and September) and winter (December and January). There were seasonal differences in ion concentration in seminal plasma and in the mRNA for various ion channels known to be involved in acrosome reactions. Furthermore, the proportion of sperm cells with damaged acrosomes was higher in post-thaw semen collected in the summer than in its counterpart collected in winter (54.2 ± 3.5% vs. 51.4 ± 1.9%, respectively; P < 0.08Further examination is required to determine whether such alterations are involved in the low summer fertility of dairy cows.
4
Wolfenson, David, William W. Thatcher, Rina Meidan, Charles R. Staples, and Israel Flamenbaum. Hormonal and Nutritional Stretegies to Optimize Reproductive Function and Improve Fertility of Dairy Cattle during Heat Stress in Summer. United States Department of Agriculture, August 1994. http://dx.doi.org/10.32747/1994.7568773.bard.
Abstract:
The BARD program includes two main parts. In the first, experiments were conducted to complete our understanding of the mechanisms responsible for the impairment of reproductive functions under heat stress. Experiments focused on follicular development and function, since results obtained in our previous BARD project indicate that the preovulatory follicle is susceptible to heat stress. The theca cells, sensitive to thermal stress, produced less androgen during the summer, as well as during the autumn. Similarly, luteinized theca cells obtained from cows in summer produced much less progesterone than in winter. Granulosa cells and luteinized granulosa cells were less susceptible to heat stress. A delayed effect of heat stress on follicular development, on suppression of dominance and on steroid production by theca and granulosa cells was noted. This may be related to the low fertility of cows during the cool months of autumn. In the second part, experiments were conducted aiming to improve fertility in summer. The timed AI program was developed using two injections of GnRH coupled with PGF2a. It was found effective in improving reproductive performance in lactating cows. Limitations induced by heat stress on estrus detection were eliminated with the timed AI management program. Replacing the second injection of GnRH with hCG instead of GnRH agonist increased plasma progesterone levels post ovulation but did not improve fertility. Use of the timed AI program in summer, shortened days open and increased the net revenue per cow, however, it did not protect the embryo fiom temperature-induced embryonic mortality. Incorporation of a GnRH-agonist implant into the timed AJ program was examined. The implant increased plasma progesterone and LH concentrations and altered follicular dynamics. The use of a GnRH-implant enhanced pregnancy rate in cows with low body conditions. In a timed embryo transfer experiment, the use of fresh or frozen in vitro produced embryos was compared in the summer to improve fertility. The use of flesh embryos (but not frozen ones) improved pregnancy rate, however, substantial embryonic death occurred between 21 and 45 days. The timed AI program, which is now being used commercially, shortened days open, and increased pregnancy rate during summer. Other approaches which were found to improve fertility in small-scale studies, need to be tested again in large-scale field trials.
5
Adelberg, Jeff, Halina Skorupska, Bill Rhodes, Yigal Cohen, and Rafael Perl-Treves. Interploid Hybridization of Cucumis melo and C. metuliferus. United States Department of Agriculture, December 1999. http://dx.doi.org/10.32747/1999.7580673.bard.
Abstract:
The long-term motivation for this research is to transfer useful traits from a broad based gene pool of wild species into the narrow base of a cultivated crop in Cucumis. Our primary focus was to use polyploid prior to fertilization as a tool to overcome fertility barriers in the cross between C. melo and C. metuliferus. In conducting this research, we explored all combinations of tetraploid and diploid parents, in reciprocal combinations. Pollinations were made in both the field and greenhouse, using emasculated flowers, moneocious females, and open pollination by insect vectors, with morphological selection criteria. After observations of thousands of ovaries, we still have no definitive proof that this hybridization yielded viable embryos. The most promising results came from using tetraploid C. metuliferus, as the maternal parent in the interspecific hybridization, that set fruit were seeds contained small embryos that did not germinate. To obtain fruit set, it was important to rear plants in a cooler sunny greenhouse, as would be found in late winter/early spring. A second interspecific hybrid between wild and cultivated Cucumis, C. hystrix x C. sativus, yielded fertile progeny for the first time, while concomitantly working toward our primary goal. Two distinct treatments were necessary; 1) special plant husbandry was necessary to have the wild species produce fruit in cultivation, and 2) embryo rescue followed by chromosome doubling in vitro was required for fertility restoration. Backcrosses to crop species and resistance to nematodes are compelling areas for further work.
6
Bonfil, David J., Daniel S. Long, and Yafit Cohen. Remote Sensing of Crop Physiological Parameters for Improved Nitrogen Management in Semi-Arid Wheat Production Systems. United States Department of Agriculture, January 2008. http://dx.doi.org/10.32747/2008.7696531.bard.
Abstract:
To reduce financial risk and N losses to the environment, fertilization methods are needed that improve NUE and increase the quality of wheat. In the literature, ample attention is given to grid-based and zone-based soil testing to determine the soil N available early in the growing season. Plus, information is available on in-season N topdressing applications as a means of improving GPC. However, the vast majority of research has focused on wheat that is grown under N limiting conditions in sub-humid regions and irrigated fields. Less attention has been given to wheat in dryland that is water limited. The objectives of this study were to: (1) determine accuracy in determining GPC of HRSW in Israel and SWWW in Oregon using on-combine optical sensors under field conditions; (2) develop a quantitative relationship between image spectral reflectance and effective crop physiological parameters; (3) develop an operational precision N management procedure that combines variable-rate N recommendations at planting as derived from maps of grain yield, GPC, and test weight; and at mid-season as derived from quantitative relationships, remote sensing, and the DSS; and (4) address the economic and technology-transfer aspects of producers’ needs. Results from the research suggest that optical sensing and the DSS can be used for estimating the N status of dryland wheat and deciding whether additional N is needed to improve GPC. Significant findings include: 1. In-line NIR reflectance spectroscopy can be used to rapidly and accurately (SEP <5.0 mg g⁻¹) measure GPC of a grain stream conveyed by an auger. 2. On-combine NIR spectroscopy can be used to accurately estimate (R² < 0.88) grain test weight across fields. 3. Precision N management based on N removal increases GPC, grain yield, and profitability in rainfed wheat. 4. Hyperspectral SI and partial least squares (PLS) models have excellent potential for estimation of biomass, and water and N contents of wheat. 5. A novel heading index can be used to monitor spike emergence of wheat with classification accuracy between 53 and 83%. 6. Index MCARI/MTVI2 promises to improve remote sensing of wheat N status where water- not soil N fertility, is the main driver of plant growth. Important features include: (a) computable from commercial aerospace imagery that include the red edge waveband, (b) sensitive to Chl and resistant to variation in crop biomass, and (c) accommodates variation in soil reflectance. Findings #1 and #2 above enable growers to further implement an efficient, low cost PNM approach using commercially available on-combine optical sensors. Finding #3 suggests that profit opportunities may exist from PNM based on information from on-combine sensing and aerospace remote sensing. Finding #4, with its emphasis on data retrieval and accuracy, enhances the potential usefulness of a DSS as a tool for field crop management. Finding #5 enables land managers to use a DSS to ascertain at mid-season whether a wheat crop should be harvested for grain or forage. Finding #6a expands potential commercial opportunities of MS imagery and thus has special importance to a majority of aerospace imaging firms specializing in the acquisition and utilization of these data. Finding #6b on index MCARI/MVTI2 has great potential to expand use of ground-based sensing and in-season N management to millions of hectares of land in semiarid environments where water- not N, is the main determinant of grain yield. Finding #6c demonstrates that MCARI/MTVI2 may alleviate the requirement of multiple N-rich reference strips to account for soil differences within farm fields. This simplicity will be less demanding of grower resources, promising substantially greater acceptance of sensing technologies for in-season N management.