871 research outputs found
A bulletin from Greece: a health system under the pressure of the second COVID-19 wave
No full textIn this article, we analyze the cascade of events since the beginning of the coronavirus disease 2019 (COVID-19) pandemic in Greece, with emphasis on the crisis' management so as to preserve the functionality of the national health system, which remains vulnerable due to the financial recession of the previous decade and chronic shortcomings . We compare and contrast the situation during the first and second epidemic wave. Understanding what possibly went wrong and when, is crucial. Such knowledge provides valuable guidance for the confrontation of the strong second wave that we are currently facing in Europe and other regions around the globe, as well as for the future waves that may follow
Algorithmic Design and Analysis of Architectural Origami
No full textThe objective of this research is to explore the ability of folded origami tessellations to adapt to free-form surface configurations and to evaluate the structural behavior of these folded tessellations for architectural and engineering applications. A mathematical exploration of the kinematics of folding provides the basis for understanding the relationship between the geometric parameters of the Miura-Ori origami fold pattern and the flexibility of the three-dimensional folded form. The structural behavior of folded plate structures derived from the Miura pattern on an architectural scale is studied in an effort to answer the question: does function follow fold? A parametric workflow provides the platform for evaluating the effect of fold pattern variations on the structural performance of the folded geometry, and computational methods are used to optimize the performance of the structure
A quantitative analysis of the US materials flow methodology and comparison to the EU methodology for MSW statistics
No full textThe European Union (EU) and the United States (US) determine municipal solid waste (MSW) statistics differently. The EU applies a site-specific methodology that directly measures waste whereas the US employs a materials flow methodology that estimates MSW statistics indirectly based on production and recovery data from industries. This study dissects the materials flow methodology and presents quantitative materials flow Sankey diagrams for the primary MSW materials to highlight data gaps that can be addressed to improve the methodology’s accuracy. Private industry plastics data were applied to the materials flow methodology, and the results were within 10% of the plastics statistics reported by the US Environmental Protection Agency (US EPA). Drawbacks to the methodologies include EU measurement inaccuracies due to double-counting and not accounting for residual waste in the US. The latter may partially explain why landfilling tonnages reported by the US EPA were approximately 60% less than the tonnages reported by the Waste to Energy Research and Technology Council (WTERT) in its national MSW survey that applied the EU methodology in the US. Unlike the EU, there is no US national policy that requires states to measure and report state-level waste data to the US EPA. Future improvements in US MSW statistics rely heavily on the implementation of national policies to homogenize the measurement and collection of waste data from states
Articulated Surfaces. A parametric approach to form-finding and structural evaluation
No full textThe objective of this research is to explore the ability of folded origami tessellations to adapt to free-form surface configurations in the context of architectural and engineering applications. The relationship between origami pattern variables, the geometry of the associated folded form, and the structural behaviour of the folded form on an architectural scale are studied. The study aims to answer the questions: Does function follow fold? Can fold follow function? A parametric workflow provides the platform for evaluating the affect of fold pattern variations on the structural performance of the folded geometry and computational methods are used to optimize the performance of the structure by varying pattern geometry
Developing a financial forecasting tool for a pre-revenue B2B SaaS early stage startup company
No full textThis thesis aims to create an easy-to-use and scalable financial forecasting tool for the needs of a commissioning company, a B2B SaaS pre-revenue early-stage startup. The primary objective is to construct a tool in an Excel spreadsheet tailored for the company to assist in its financial planning.
The need for the tool arose when the author joined the company as a financial intern. Based on discussions with the company's management team, it was clear that a lack of financial planning and expertise existed. Through this thesis, the author seeks to create a tool that will allow the management to more efficiently plan the company’s finances for the future; this in turn can help the business when preparing financial forecasts to obtain funding and other forms of investments.
The author reached the goals of the thesis through the study of relevant accounting principles and theory regarding how financial projections are built. He did this in relation to the SaaS industry in which the company operates, and in doing so, key industry characteristics are mentioned throughout the process. He then assessed the internal structure of the company and attempted to understand the goals and targets of the business and to determine many of the assumptions that will were utilised for the design of the tool and the financial projections.
In addition, several recommendations were provided to the company to improve its efficiency and maximise the use of the tool, and the author ends the thesis by discussing the key outcomes, recommendations and suggestions for further research. The author’s personal evaluation on the project and his reflection on learning are also covered at the end
European primary datasets of alien bacteria and viruses
No full textBacteria and viruses are a natural component of Earth biodiversity and play an essential role in biochemical and geological cycles. They may also pose problems outside their native range, where they can negatively impact on natural resources, wildlife, and human health. To address these challenges and develop sustainable conservation strategies, a thorough understanding of their invasion related- factors is needed: origin, country and year of introduction, and pathways dynamics. Yet, alien bacteria and viruses are underrepresented in invasion ecology studies, which limits our ability to quantify their impacts and address future introductions. This study provides primary datasets of alien bacteria and viruses of plants and animals present in the European environment. The datasets contain expert-revised data on 446 taxa and their invasion related- factors across terrestrial and aquatic environments. Taxa information are complemented with spatial occurrences. The datasets provide a basis for collaborative initiatives to improve the collection of alien bacteria and viruses' data, and a starting point for data-driven conservation practices
Continuous wave quantum light control via engineered Rydberg induced dephasing
No full textWe analyze several variations of a single-photon optical switch operating in
the continuous wave regime, as presented in the accompanying paper [Tsiamis et
al., Continuous wave single photon switch based on a Rydberg atom ensemble].
The devices are based on ensembles of Rydberg atoms that interact through van
der Waals interaction. Continuously probing the atomic cloud with a weak
coherent probe field, under the conditions of electromagnetically induced
transparency (EIT) leads to total reflection/transmission of the probe in the
absence of control photons. Exciting a Rydberg state with a single control
photon breaks the EIT conditions, drastically altering the probe's
reflectance/transmittance. We examine how the collective Rydberg interaction in
an atomic ensemble enclosed in an optical cavity or in free space induces two
probe-induced dephasing processes. These processes localize the control photons
and modify the probe's reflectance/transmittance, enhancing the lifetime of
control excitations and increasing the devices' efficiency. The devices are
characterized by the probability to absorb a control photon and the associated
gain as described by the change in the probe's reflectance/transmittance. The
results are confirmed through numerical calculations of realistic one- and
three-dimensional atomic ensembles in a cavity and an one-dimensional atomic
ensemble in free space. The proposed continuous wave devices complement
previously realized single photon transistors and expand the possible quantum
light manipulation circuitry
Early development of Gongolaria montagnei (Fucales, Phaeophyta) germlings under laboratory conditions, with a view to enhancing restoration potential in the Eastern Mediterranean
No full textThe loss of Mediterranean macroalgal populations
dominated by Cystoseira sensu lato is driven by a
multitude of pressures. In the eastern Mediterranean Sea,
climate change and the establishment of Lessepsian herbivore
species have further intensified the ongoing decline
of these canopy-forming algae. Knowledge of the reproductive
phenology, embryology and growth of Cystoseira
species is the first step towards successful reforestation
measures. Gongolaria montagnei is one of the most common
canopy-forming algal species with a wide horizontal
and vertical distribution along the Greek coasts. Mature
receptacles were collected from Saronikos Gulf (Aegean
Sea), and germlings were cultured in mesocosms for
34 days, reaching up to 1.30 mm in length. Divisions and
early developmental stages of G. montagnei are described
and possible implications for future restoration efforts are
discussed. A new approach to growth rate modeling, based
on surface measurements of embryos and germlings is
presented
CoExpresso: Assess the quantitative behavior of protein complexes in human cells
No full textAbstract Background Translational and post-translational control mechanisms in the cell result in widely observable differences between measured gene transcription and protein abundances. Herein, protein complexes are among the most tightly controlled entities by selective degradation of their individual proteins. They furthermore act as control hubs that regulate highly important processes in the cell and exhibit a high functional diversity due to their ability to change their composition and their structure. Better understanding and prediction of these functional states demands methods for the characterization of complex composition, behavior, and abundance across multiple cell states. Mass spectrometry provides an unbiased approach to directly determine protein abundances across different cell populations and thus to profile a comprehensive abundance map of proteins. Results We provide a tool to investigate the behavior of protein subunits in known complexes by comparing their abundance profiles across up to 140 cell types available in ProteomicsDB. Thorough assessment of different randomization methods and statistical scoring algorithms allows determining the significance of concurrent profiles within a complex, therefore providing insights into the conservation of their composition across human cell types as well as the identification of intrinsic structures in complex behavior to determine which proteins orchestrate complex function. This analysis can be extended to investigate common profiles within arbitrary protein groups. CoExpresso can be accessed through http://computproteomics.bmb.sdu.dk/Apps/CoExpresso. Conclusions With the CoExpresso web service, we offer a potent scoring scheme to assess proteins for their co-regulation and thereby offer insight into their potential for forming functional groups like protein complexes
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