11,016 research outputs found

    Statistical-dynamical analyses and modelling of multi-scale ocean variability

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    This thesis aims to provide a comprehensive analysis of multi-scale oceanic variabilities using various statistical and dynamical tools and explore the data-driven methods for correct statistical emulation of the oceans. We considered the classical, wind-driven, double-gyre ocean circulation model in quasi-geostrophic approximation and obtained its eddy-resolving solutions in terms of potential vorticity anomaly and geostrophic streamfunctions. The reference solutions possess two asymmetric gyres of opposite circulations and a strong meandering eastward jet separating them with rich eddy activities around it, such as the Gulf Stream in the North Atlantic and Kuroshio in the North Pacific. This thesis is divided into two parts. The first part discusses a novel scale-separation method based on the local spatial correlations, called correlation-based decomposition (CBD), and provides a comprehensive analysis of mesoscale eddy forcing. In particular, we analyse the instantaneous and time-lagged interactions between the diagnosed eddy forcing and the evolving large-scale PVA using the novel `product integral' characteristics. The product integral time series uncover robust causality between two drastically different yet interacting flow quantities, termed `eddy backscatter'. We also show data-driven augmentation of non-eddy-resolving ocean models by feeding them the eddy fields to restore the missing eddy-driven features, such as the merging western boundary currents, their eastward extension and low-frequency variabilities of gyres. In the second part, we present a systematic inter-comparison of Linear Regression (LR), stochastic and deep-learning methods to build low-cost reduced-order statistical emulators of the oceans. We obtain the forecasts on seasonal and centennial timescales and assess them for their skill, cost and complexity. We found that the multi-level linear stochastic model performs the best, followed by the ``hybrid stochastically-augmented deep learning models''. The superiority of these methods underscores the importance of incorporating core dynamics, memory effects and model errors for robust emulation of multi-scale dynamical systems, such as the oceans.Open Acces

    Forested buffers in agricultural landscapes : mitigation effects on stream–riparian meta-ecosystems

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    Stream–riparian meta-ecosystems are strongly connected through exchanges of energy, material and organisms. Land use can disrupt ecological connectivity by affecting community composition directly and/or indirectly by altering the instream and riparian habitats that support biological structure and function. Although forested riparian buffers are increasingly used as a management intervention, our understanding of their effects on the functioning of stream–riparian metaecosystems is limited. This study assessed patterns in the longitudinal and lateral profiles of streams in modified landscapes across Europe and Sweden using a pairedreach approach, with upstream unbuffered reaches lacking woody riparian vegetation and with downstream reaches having well-developed forested buffers. The presence of buffers was positively associated with stream ecological status as well as important attributes, which included instream shading and the provision of suitable habitats for instream and riparian communities, thus supporting more aquatic insects (especially EPT taxa). Emergence of aquatic insects is particularly important because they mediate reciprocal flows of subsidies into terrestrial systems. Results of fatty acid analysis and prey DNA from spiders further supported the importance of buffers in providing more aquatic-derived quality food (i.e. essential fatty acids) for riparian spiders. Findings presented in this thesis show that buffers contribute to the strengthening of cross-ecosystem connectivity and have the potential to affect a wide range of consumers in modified landscapes

    The Adirondack Chronology

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    The Adirondack Chronology is intended to be a useful resource for researchers and others interested in the Adirondacks and Adirondack history.https://digitalworks.union.edu/arlpublications/1000/thumbnail.jp

    BECOMEBECOME - A TRANSDISCIPLINARY METHODOLOGY BASED ON INFORMATION ABOUT THE OBSERVER

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    ABSTRACT Andrea T. R. Traldi BECOMEBECOME A Transdisciplinary Methodology Based on Information about the Observer The present research dissertation has been developed with the intention to provide practical strategies and discover new intellectual operations which can be used to generate Transdisciplinary insight. For this reason, this thesis creates access to new knowledge at different scales. Firstly, as it pertains to the scale of new knowledge generated by those who attend Becomebecome events. The open-source nature of the Becomebecome methodology makes it possible for participants in Becomebecome workshops, training programmes and residencies to generate new insight about the specific project they are working on, which then reinforce and expand the foundational principles of the theoretical background. Secondly, as it pertains to the scale of the Becomebecome framework, which remains independent of location and moment in time. The method proposed to access Transdisciplinary knowledge constitutes new knowledge in itself because the sequence of activities, described as physical and mental procedures and listed as essential criteria, have never been found organised 6 in such a specific order before. It is indeed the order in time, i.e. the sequence of the ideas and activities proposed, which allows one to transform Disciplinary knowledge via a new Transdisciplinary frame of reference. Lastly, new knowledge about Transdisciplinarity as a field of study is created as a consequence of the heretofore listed two processes. The first part of the thesis is designated ‘Becomebecome Theory’ and focuses on the theoretical background and the intellectual operations necessary to support the creation of new Transdisciplinary knowledge. The second part of the thesis is designated ‘Becomebecome Practice’ and provides practical examples of the application of such operations. Crucially, the theoretical model described as the foundation for the Becomebecome methodology (Becomebecome Theory) is process-based and constantly checked against the insight generated through Becomebecome Practice. To this effect, ‘information about the observer’ is proposed as a key notion which binds together Transdisciplinary resources from several studies in the hard sciences and humanities. It is a concept that enables understanding about why and how information that is generated through Becomebecome Practice is considered of paramount importance for establishing the reference parameters necessary to access Transdisciplinary insight which is meaningful to a specific project, a specific person, or a specific moment in time

    Optical coherence tomography methods using 2-D detector arrays

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    Optical coherence tomography (OCT) is a non-invasive, non-contact optical technique that allows cross-section imaging of biological tissues with high spatial resolution, high sensitivity and high dynamic range. Standard OCT uses a focused beam to illuminate a point on the target and detects the signal using a single photodetector. To acquire transverse information, transversal scanning of the illumination point is required. Alternatively, multiple OCT channels can be operated in parallel simultaneously; parallel OCT signals are recorded by a two-dimensional (2D) detector array. This approach is known as Parallel-detection OCT. In this thesis, methods, experiments and results using three parallel OCT techniques, including full -field (time-domain) OCT (FF-OCT), full-field swept-source OCT (FF-SS-OCT) and line-field Fourier-domain OCT (LF-FD-OCT), are presented. Several 2D digital cameras of different formats have been used and evaluated in the experiments of different methods. With the LF-FD-OCT method, photography equipment, such as flashtubes and commercial DSLR cameras have been equipped and tested for OCT imaging. The techniques used in FF-OCT and FF-SS-OCT are employed in a novel wavefront sensing technique, which combines OCT methods with a Shack-Hartmann wavefront sensor (SH-WFS). This combination technique is demonstrated capable of measuring depth-resolved wavefront aberrations, which has the potential to extend the applications of SH-WFS in wavefront-guided biomedical imaging techniques

    Novel strategies for the modulation and investigation of memories in the hippocampus

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    Disruptions of the memory systems in the brain are linked to the manifestation of many neuropsychiatric diseases such as Alzheimer’s disease, depression, and post-traumatic stress disorder. The limited efficacy of current treatments necessities the development of more effective therapies. Neuromodulation has proven effective in a variety of neurological diseases and could be an attractive solution for memory disorders. However, the application of neuromodulation requires a more detailed understanding of the network dynamics associated with memory formation and recall. In this work, we applied a combination of optical and computational tools in the development of a novel strategy for the modulation of memories, and have expanded its application for interrogation of the hippocampal circuitry underlying memory processing in mice. First, we developed a closed-loop optogenetic stimulation platform to activate neurons implicated in memory processing (engram neurons) with a high temporal resolution. We applied this platform to modulate the activity of engram neurons and assess memory processing with respect to synchronous network activity. The results of our investigation support the proposal that encoding new information and recalling stored memories occur during distinct epochs of hippocampal network-wide oscillations. Having established the high efficacy of the modulation of engram neurons’ activity in a closed-loop fashion, we sought to combine it with two-photon imaging to enable high spatial resolution interrogation of hippocampal circuitry. We developed a behavioral apparatus for head-fixed engram modulation and the assessment of memory recall in immobile animals. Moreover, through the optimization of dual color two-photon imaging, we improved the ability to monitor activity of neurons in the subfields of the hippocampus with cellular specificity. The platform created here will be applied to investigate the effects of engram reactivation on downstream projections targets with high spatial and cell subtype specificity. Following these lines of investigations will enhance our understanding of memory modulation and could lead to novel neuromodulation treatments for neurological disorders associated with memory malfunctioning

    Le distanciel est-il le nouveau présentiel? Les effets de la pandémie sur les bibliothécaires de référence des universités en Turquie

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    La pandĂ©mie de la COVID-19, dont les effets se font ressentir Ă  partir de la fin de l’annĂ©e 2019, domine toutes les dimensions de la vie dans le monde entier. La communautĂ© internationale Ă  travers l’OMS incite les pays Ă  se confiner, compte tenu du nombre de cas et de morts en augmentation. MalgrĂ© la dĂ©couverte des vaccins, l’isolement et le confinement se poursuivent. La COVID-19 a Ă©galement d’importantes consĂ©quences sur la vie professionnelle. Pour nombre de groupes professionnels, la crise sanitaire se traduit par une adaptation Ă  cette nouvelle forme de travail. Le confinement entraĂźne la mise en place de modes de travail inhabituels comme le tĂ©lĂ©travail auquel la plupart des cadres professionnels n’était pas prĂ©parĂ©e. La structure hybride du tĂ©lĂ©travail risque de rĂ©duire les frontiĂšres entre la vie professionnelle et la vie privĂ©e et de menacer le droit Ă  la vie privĂ©e. Il est incontestable que la COVID-19 a aussi des impacts profonds sur les maniĂšres de travailler des professionnels d’information. Notre Ă©tude vise Ă  obtenir une meilleure comprĂ©hension des effets du tĂ©lĂ©travail en confinement sur les services et les bibliothĂ©caires de rĂ©fĂ©rence des bibliothĂšques universitaires dans la pĂ©riode pandĂ©mique en Turquie. Dans cette Ă©tude quantitative, la mĂ©thode privilĂ©giĂ©e Ă©tait l’enquĂȘte par questionnaire en ligne. Selon les donnĂ©es que nous avons collectĂ©es par l’intermĂ©diaire d’un questionnaire en ligne, nous avons constatĂ© que le tĂ©lĂ©travail en confinement estompait les frontiĂšres entre la sphĂšre professionnelle et la sphĂšre privĂ©e des bibliothĂ©caires de rĂ©fĂ©rence surtout avec enfant(s) ou en couple. Cette Ă©tude nous a Ă©galement permis de dĂ©terminer les types de services de rĂ©fĂ©rence et les ressources, surtout numĂ©riques, pour offrir ce service. Elle nous a aidĂ© aussi Ă  Ă©valuer les effets des facteurs comme le genre et l’infrastructure technologique, et Ă  voir Ă  quel niveau le domicile convenait pour ce type de travail. Selon nous, les rĂ©sultats de cette recherche pourraient ĂȘtre rĂ©vĂ©lateurs pour dĂ©terminer la feuille de route dans ce processus. Aussi, notre Ă©tude contribuera Ă  combler les manques dans ce domaine et Ă  identifier des pistes de rĂ©flexion pour les recherches futures.The COVID-19 pandemic whose effects have been felt from the end of 2019, has dominated all aspects of public life across the globe. International community through the WHO incite countries to lock down because of the increasing number of cases and deaths. Despite the discovery of vaccines, isolation and lockdown continue. The global spread of the coronavirus has significant consequences on professional life. For many professionals, this health crisis resulted in adaptation to a new form of working. The lockdown introduced new and unusual ways of working like telecommuting for whom most of the professionals were not prepared. Hybrid structure of telecommuting could reduce boundaries between professional and personal life and threaten right to privacy. There is compelling evidence that COVID-19 has also deep impacts on the way that information professionals work. Our study aimed at understanding the effects of telecommuting on private sphere, and changes in reference services offered by university librarians during pandemic in Turkey. Our studies show the consequences of social distancing on reference services, which normally necessitate a proximity between librarian and user, and how telecommuting during the lockdown blur boundaries between professional and private sphere. In the “new normal”, private sphere is a hybrid space which includes both spheres. The method that we have adopted was online questionnaire survey to obtain a portrait of the impacts of telecommuting during the lockdown on references services and on reference librarians who are working at university libraries in Turkey. In our opinion, our study would fill the lack in this field and contribute to adopt measures especially for the future. Using data provided by an Internet-based survey questionnaire, our study aimed also aimed at grasping new definitions of work introduced by the “new normal” and at observing the effects of new professional perspectives on information sciences and especially on reference librarians in Turkey. Also, this study helped us to understand changes in factors like gender, social divide, and private life in this unprecedented period. In our opinion, the results of this study could be revealing to determine the roadmap in this process
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