114 research outputs found
UMD Resilient Adaptive Climate Technology ThinkTank (reACT TT): Purpose, Accomplishments and Future Directions
reACT ThinkTank is a campus-wide initiative involving faculty, staff, and students collaborating with Maryland tribal communities, who are deeply committed to a dynamic transdisciplinary approach to sustainability that includes research, consultancy advice, and education to internal and external stakeholders concerning climate change, regenerative design and renewable energy in urban environments and the building industry, and providing opportunities for action related to the Universityâs Land Acknowledgment
Sex expression and the selection and Ă©volution of combined sexes in the dioecious annual herb Mercurialis annua
The flowering plants display a large variety of sexual systems that has long astonished botanists. The great majority of species are hermaphroditic, carrying male and female organs within the same flower, while others are characterized by sexes separated between different individuals, a system termed dioecy. The later is likely to have evolved from the ancestral state of hermaphroditism and had long been considered an evolutionary dead-end. However recent progress in our understanding of transitions between sexual systems in plants has shed light on frequent transitions away from dioecy, arguing against the evolutionary dead-end hypothesis. The determinants of transitions towards dioecy likely involve an intermediate step of either gynodioecy (where females coexist with hermaphrodites) or monoecy (where individuals carry unisexual flowers of both sexes). The principle aim of this thesis was to investigate factors that may lead dioecious species towards a state of combined sexes, either hermaphroditism or monoecy. My investigation builds on seminal work conducted by the evolutionary theorist David Lloyd in the 1970s, who observed the often labile nature of sex expression in dioecious populations, where females and males may sometimes produce pollen or seeds, respectively. Lloyd proposed that this âinconstancyâ or âleakinessâ in sex expression constitutes variation on which natural selection can act to bring about the breakdown of dioecy and the evolution of combined sexes. To investigate this idea, I studied populations of Mercurialis annua, a dioecious herb growing in Europe and around the Mediterranean Basin and that is characterized by the presence of lability in sex expression. My goals were to assess how males and females differ, both in their patterns of inconstancy and the underlying gene expression profiles, and to determine the functionality of this inconstancy in natural dioecious populations. I found that most of the inconstant reproductive effort of both males and females had a negligible effect on fitness in natural conditions. However, I reasoned that when plants are isolated from large populations, inconstant individuals should enjoy a strong advantage by being able to reproduce by selfing. Because I detected that females were more frequently inconstant than males in natural populations, I hypothesized that females should benefit more from isolation. I tested this hypothesis by removing males from experimental populations of dioecious M. annua and allowing the remaining females to evolve in their absence. These females showed a dramatic increase in pollen production over four generations, with a large proportion of the male-less populations being functionally hermaphroditic. I also investigated how the profiles of sex expression in the evolved individuals had shifted, and found that most of the genes that were originally more highly expressed in males than females to be up-regulated as well in the selected females. Together, my results show that inconstancy is a trait underlined by genetic variation on which selection may act during episodes of isolation, and can indeed provide a starting point for transitions away from dioecy.
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La grande diversitĂ© de systĂšmes sexuels qui prĂ©sentent les plantes Ă fleurs Ă depuis longtemps intriguĂ© les botanistes. La grande majoritĂ© des espĂšces sont hermaphrodites, portant les organes mĂąles et femelles au sein de la mĂȘme fleur, tandis quâune minoritĂ© se caractĂ©rise par la sĂ©paration des sexes entre diffĂ©rents individus, un systĂšme appelĂ© dioĂ©cie. Ce-dernier a probablement Ă©voluĂ© Ă partir de lâĂ©tat ancestral hermaphrodite et a longtemps Ă©tĂ© considĂ©rĂ© comme une impasse Ă©volutive. Cependant de rĂ©centes avancĂ©es dans notre comprĂ©hension de lâĂ©volution des transitions entre systĂšmes sexuels chez les plantes semblent indiquer que la dioĂ©cie peut Ă©voluer vers des systĂšmes oĂč les sexes sont combinĂ©s, contredisant lâhypothĂšse de lâimpasse Ă©volutive. Les dĂ©terminants des transitions vers la dioĂ©cie impliquent sĂ»rement des Ă©tapes intermĂ©diaires de gynodioĂ©cie (oĂč femelles et hermaphrodites coexistent) ou de monoĂ©cie (oĂč les individus portent des fleurs unisexuelles des deux sexes). Le but principal de cette thĂšse est dâĂ©tudier les facteurs qui peuvent amener une espĂšce dioĂŻque a transiter vers un Ă©tat de sexes combinĂ©s, soit lâhermaphroditisme, soit la monoĂ©cie. Mon Ă©tude se base sur le travail fondateur du thĂ©oricien David Lloyd dans les annĂ©es 1970, qui a observĂ© que la nature souvent labile de lâexpression du sexe dans les populations dioĂŻques, oĂč les femelles et les mĂąles parfois produisent du pollen et des graines, respectivement. Lloyd a proposĂ© que cette âinconstanceâ dans lâexpression du sexe pourrait constituer un variation sur laquelle la sĂ©lection pourrait agir et dĂ©clencher une rupture de la dioĂ©cie et lâĂ©volution dâun systĂšme oĂč les sexes sont combinĂ©s. Afin dâexplorer cette idĂ©e, jâai Ă©tudiĂ© les populations de Mercurialis annua, une herbe dioĂŻque prĂ©sente en Europe et autour du bassin mĂ©diterranĂ©en, caractĂ©risĂ©e par la prĂ©sence dâinconstance de lâexpression du sexe. Mes objectifs Ă©taient dâestimer la divergence entre les mĂąles et les femelles, Ă la fois dans la façon dont ils expriment lâinconstance du sexe et dans leur profiles dâexpression de gĂšnes, et de dĂ©terminer la fonctionnalitĂ© de lâinconstance dans les populations naturelles. Jâai trouvĂ© que la majeure partie des organes sexuels produits par inconstance nâavaient quâun effet nĂ©gligeable sur le succĂšs reproducteur dâun individu. Cependant il apparaĂźt que lorsque les plantes se retrouvent isolĂ©es des larges populations, les individus inconstant devraient bĂ©nĂ©ficier dâun fort avantage en Ă©tant capables de se reproduire par autofĂ©condation. Parce que jâai dĂ©tectĂ© que les femelles Ă©taient plus frĂ©quemment inconstantes que les mĂąles dans les populations naturelles, jâai Ă©mis lâhypothĂšse que les femelles devraient ĂȘtre particuliĂšrement avantagĂ©es en cas dâisolement. Jâai testĂ© cette hypothĂšse en constituant des populations expĂ©rimentales de M. annua dioĂŻque desquelles jâai supprimĂ© les mĂąles, en laissant les femelles Ă©voluer en leur absence. Ces femelles ont montrĂ© une importante augmentation de leur production de pollen en quatre gĂ©nĂ©rations, avec une large fraction de ces populations expĂ©rimentales Ă©tant effectivement fonctionnellement hermaphrodites. Jâai aussi Ă©tudiĂ© la façon dont les profiles dâexpression de gĂšnes qui diffĂ©renciaient les mĂąles et les femelles dans les populations naturelles ont Ă©voluĂ©s chez durant lâexpĂ©rience. Je montre que la plupart des gĂšnes qui Ă©taient naturellement plus fortement exprimĂ©s chez les mĂąles que les femelles avaient Ă©tĂ© surexprimĂ©s chez les femelles Ă©voluĂ©es. Mes rĂ©sultats suggĂšrent que lâinconstance du sexe est un trait soutenu par une variation gĂ©nĂ©tique sur laquelle la sĂ©lection peut effectivement agir durant des Ă©pisodes dâisolement et peut, en effet, fournir un point de dĂ©part Ă des transitions depuis un Ă©tat dioĂŻque vers un Ă©tat de sexes combinĂ©s
After Many Springs: Regionalism, Modernism & the Midwest
Book Review of After Many Springs: Regionalism, Modernism & the Midwest / Debra Bricker Balken--ISBN 9780300135862. Reviewed by Patricia Kosco Cossard
Ăvaluation de la surface frontale comme Ă©lĂ©ment dâamĂ©lioration de lâaĂ©rodynamisme en cyclisme
Introduction : En cyclisme, la reÌsistance aeÌrodynamique est la force principale qui sâoppose aÌ son deÌplacement et devient non neÌgligeable deÌs 10 m/s. La surface de traiÌneÌe (CDAP) constitue un facteur important de cette dernieÌre et varie en fonction de la surface frontale (AP). Ce projet de recherche veut eÌvaluer la fiabiliteÌ et la validiteÌ dâune meÌthode de mesure accessible de la surface frontale (AP). MeÌthode : 14 cyclistes ont eÌteÌ seÌlectionneÌs : 31 14 ans; 177,21 6,73 cm; 74,83 8,97 kg et diviseÌs en deux groupes, amateurs et experts. La meÌthode par digitalisation est utiliseÌe pour lâeÌvaluation de Ap et une meÌthode par reÌgression lineÌaire est utiliseÌe pour CDAP en utilisant le logiciel MATLAB_R2019. ReÌsultats : la surface frontale obtenue est AP = P1, 0,433 0,05 m2; P2, 0,413 0,04 m2; P3, 0,387 0,05 m2 avec un ICC intra ; 0,998, et un ICC inter ; 0,523 (p < 0,05). Pour CDAP = P1, 0,414 0,07 m2; P2, 0,435 0,14 m2; P3, 0,399 0,12 m2 avec une variation de R = 0,10 aÌ 0,34. Conclusion : la mesure de AP avec une meÌthode simple est valide et fiable, mais la preÌcision varie selon lâexpertise de lâopeÌrateur. La faible correÌlation entre AP et CDAP montre que AP ne devrait pas eÌtre la seule variable aÌ laquelle nous pouvons nous fier pour ameÌliorer CDAP. LâeÌvaluation de la surface frontale projeteÌe par digitalisation permettrait dâameÌliorer la performance aeÌrodynamique en cyclisme. Dâautres recherches dâoptimisation des outils dâeÌvaluation aeÌrodynamique permettraient dâobtenir des reÌsultats plus preÌcis.Introduction : In the cycling world, aerodynamic resistance is the principal force that oppose a moving cyclist and is most important at 10 m/s. Drag area (CDAP) is an important factor of this force and depends of the frontal area (AP). This project wants to evaluate the reliability and the validity of an accessible method of measurements of the frontal area (AP). Method : 14 cyclists were selected : 31 14 years; 177,21 6,73 cm; 74,83 8, 97 kg and divided in two groupes, amateurs et experts. The digital method is used for the evaluation of Ap and a linear regression is used with MATLAB_R2019 for finding CDAP. RĂ©sults : the obtained frontal area AP = P1, 0,433 0,05 m2; P2, 0,413 0,04 m2; P3, 0,387 0,05 m2 with an ICC intra-operator; 0,998, and an ICC inter-operator; 0,523 (p < 0,05). Pour CDAP = P1, 0,414 0,07 m2; P2, 0,435 0,14 m2; P3, 0,399 0,12 m2 with a correlation variation of R = 0,10 Ă 0, 34. Conclusion : Measuring Ap with a simple method is reliable and present good validity, but the precision will vary with the expertise of the operator. The weak correlation between AP and CDAP show that AP shouldnât be the only variable that we have to rely to reduce CDAP. In the end, the evaluation of frontal area with a simple digital method could increase aerodynamic performance in cyclist. Although, further research on optimising aerodynamic evaluation tools would allow to obtain results that are more precise
Innovation: Serving the Studio
This Presentation delineates the origins of the University of Maryland Libraries' Kiosk and Pop-up Library services that were created by Patricia Kosco Cossard in response to the 2012 Architecture Library Needs Assessment Report & Recommendations
Serious Play: Design in Midcentury America
Review of Serious Play: Design in Midcentury America, Reviewed January 2019 by Patricia Kosco Cossard, Art Librarian, University of Maryland, [email protected]
Liaison Librarian Task Force 2012 - 2013, The University of Maryland Libraries, Final Report, 31 May 2013
This report examines the role of subject librarians in an academic environment, specifically at the University of Maryland. The Liaison Task Force offers several recommendations. These recommendations center on the creation of formal policies, guidelines and programs for liaison librarians. The bibliographies and other supplementary materials to this report include documentation for implementing the recommendations
Buildings Must Die: A Perverse View of Architecture
Review of Buildings Must Die: A Perverse View of Architecture, Reviewed September 2014 by Patricia Kosco Cossard, Art Librarian, Art & Architecture Libraries, University of Maryland, College Park, [email protected]
Curated Commons: The Maryland Model
The curated commons is a model in which a flexible library building shell and its infrastructure can respond to the specific time-sensitive needs of differing clients. It applies to faculty research, in particular small science activities (as opposed to big science activities that have major support which includes proprietary laboratories and facilities). It provides for sustained transformation of library facilities as well as its utilitarian and cyber-infrastructures to become a flexible reconfigurable space with cutting edge technology and sustained funding streams
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