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Found 6515 publications
Rankings: Blind spots in startup ecosystem research
Publication Name: Statisztikai Szemle
Publication Date: 2023-01-01
Volume: 101
Issue: 3
Page Range: 203-231
Description:
The concept of ecosystem is becoming increasingly popular in economic, scientific and policy systems alike, and its use is embedded more and more in everyday practice. It provides a theoretical framework for policy planning documents, business plans and scientific research. This is facilitated by a holistic approach that understands ecosystems not only as resource allocation systems, but also as a complex structure of governance that includes cognitive elements and interactions. In parallel with its rise in popularity, indices and rankings have been developed for measuring and comparing the performance of individual ecosystems, influencing not only the associated discourse but also the decisions of ecosystem actors. Compared to the innovation and the entrepreneurship ecosystem frameworks, the concept of a startup ecosystem is a relatively new category. Related startup ecosystem rankings, emerging in recent years, are meant to provide performance comparability of these ecosystems. These rankings and their underlying variables have not been in the center of academic interest, but the holistic nature of the ecosystem conceptual framework requires a deeper understanding and analysis of the field. As a first step, a structured synthesis of appropriate research questions and future research directions must be ensured. The present paper attempts to do this by describing the specificities of the holistic ecosystem approach and a possible research agenda on startup ecosystem rankings.
Open Access: Yes
Machine learning models for the elastic-critical buckling moment of sinusoidal corrugated web beam
Publication Name: Results in Engineering
Publication Date: 2024-09-01
Volume: 23
Issue: Unknown
Page Range: Unknown
Description:
The torsional stiffness of I-beams with sinusoidal corrugated web is higher than that of flat web beams and the accuracy of the available hand-calculation methods to determine the elastic critical lateral-torsional buckling moment depends on the geometrical parameters of the beam and the web corrugation. This study proposes different machine learning models to determine the elastic lateral-torsional buckling moments of corrugated web beams. Various machine-learning algorithms such as Decision Tree, Random Forests, Gradient Boosting, Support Vector Regression, Catboost, and Deep Neural Network were employed to develop and train for predicting the elastic-critical lateral-torsional buckling moments of I-beams with corrugated web. An extensive dataset with 2250 pieces was constructed using linear buckling analyses on full-shell finite element models to determine the elastic-critical buckling moment of simply supported beams with sinusoidal web corrugation. Based on the statistical parameters of the predicted and test data, the accuracy and safety assessment of the different machine learning models are examined. The accuracy of the available hand-calculation methods is also investigated. The results of the parametric study showed that the overall performance of the different machine learning models is promising, although, not all are directly suited for the described problem.
Open Access: Yes
Role of land use, green energy, and water resources for food accessibility: Evidence from emerging economies in the lens of COP28
Publication Name: Land Degradation and Development
Publication Date: 2024-09-01
Volume: 35
Issue: 15
Page Range: 4607-4622
Description:
In the era of COP28, where most of the developed and developing economies concentrate more on the development of environmentally friendly energy resources to tackle the issue of climate change. Nevertheless, the literature lacks appropriate evidence regarding the influences of green energy and other resources on food security. This study analyses the influences of land use, green energy, and water resources on food accessibility in emerging economies, while also considering the important roles of natural resources, research and development (R&D) expenditure, and economic growth during 1980–2020. Due to non-linear data dispersion, the novel moments quantile regression is employed. Results assert that land use has a positive significant influence on food accessibility in the presence of water resources and a weaker negative impact in the presence of natural resources. Natural and water resources are detrimental to food accessibility in the Emerging Seven (E7) countries. Furthermore, R&D expenditure and green energy positively (negatively), while economic growth negatively (positively) impacted food accessibility in the presence of natural resources (water resources). The results are robust and validate causal inferences that help develop appropriate policies for emerging economies concerning food accessibility or security. In this rapidly evolving era, most empirical studies consider environmental quality. Conversely, this study contributes to the literature by examining the factors influencing food accessibility, as this issue is of considerable importance because of the rapidly growing global population.
Open Access: Yes
DOI: 10.1002/ldr.5244
Mechanical Properties of Clay-Reinforced Polyamide 6 Nanocomposite Liner Materials of Type IV Hydrogen Storage Vessels
Publication Name: Nanomaterials
Publication Date: 2024-09-01
Volume: 14
Issue: 17
Page Range: Unknown
Description:
This study focuses on polyamide 6/organo-modified montmorillonite (PA6/OMMT) nanocomposites as potential liner materials, given the growing interest in enhancing the performance of type IV composite overwrapped hydrogen storage pressure vessels. The mechanical properties of PA6/OMMT composites with varying filler concentrations were investigated across a temperature range relevant to hydrogen storage conditions (−40 °C to +85 °C). Liner collapse, a critical issue caused by rapid gas discharge, was analyzed using an Ishikawa diagram to identify external and internal factors. Mechanical testing revealed that higher OMMT content generally increased stiffness, especially at elevated temperatures. The Young’s modulus and first yield strength exhibited non-linear temperature dependencies, with 1 wt. per cent OMMT content enhancing yield strength at all tested temperatures. Dynamic mechanical analysis (DMA) indicated that OMMT improves the storage modulus, suggesting effective filler dispersion, but it also reduces the toughness and heat resistance, as evidenced by lower glass transition temperatures. This study underscores the importance of optimizing OMMT content to balance mechanical performance and thermal stability for the practical application of PA6/OMMT nanocomposites in hydrogen storage pressure vessels.
Open Access: Yes
DOI: 10.3390/nano14171385
Music-making in microgravity: across the first 63 years (1961-2024) of spaceflight. Academy transaction note
Publication Name: Acta Astronautica
Publication Date: 2024-08-01
Volume: 221
Issue: Unknown
Page Range: 85-89
Description:
Musical expression is a characteristic of humanity on Earth. This paper highlights the historical relationship between music and spaceflight, including its use in the representation of space, and its role in space culture. The paper documents circa 57 musical instruments: from a miniaturized harmonica to a 1.5 m Digeridoo that are known to have been taken into space – usually as part of a crew members personal allowance. Due to mass and volume restrictions numerous classical and ethnographic instruments have been ‘spaceflight-adapted’, in addition to the use of digital technologies for personal musical pleasure and public relations. Furthermore, it charts how access to personalised music playlists and shared musical experiences have been deemed to be vital by crew, promoting individual wellbeing including a connection to home, to each other and playing a part in the marking of success, and tragedy. The value of music making in space is briefly described leading to the proposition that as humanity ventures with greater regularity to Low Earth Orbit and beyond, consideration of how music can be effectively utilised to support individual and crew wellbeing, whilst contributing to the cannon of human artistic expression is warranted.
Open Access: Yes
Environmental apprehension under COP26 agreement: Examining the influence of environmental-related technologies and energy consumption on ecological footprint
Publication Name: International Journal of Environmental Science and Technology
Publication Date: 2024-08-01
Volume: 21
Issue: 12
Page Range: 7999-8012
Description:
Governments internationally strive to balance environmental health and economic development. Modern economies, specifically emerging ones, emphasize the importance of eco-friendly progress, where the pace of economic growth limits the ecological footprint. The ecological footprint denotes both the trajectory of natural resource extraction in the economic process and how quickly these resources can be replenished, as well as the capacity of the ecological sector to absorb waste from this process. This study examines 38 countries from 1994 to 2020 to investigate the drivers of the ecological footprint and found that environmentally related technologies harmfully influence ecological deprivation but are positively affected by gross domestic product growth. Renewable energy diminishes pollution levels, while urbanization has an insignificant effect. Imports were only found to be significant with one econometric technique, and their impact on the ecological footprint was positive. Income level affects the influence of gross domestic product on the ecological footprint. Lower-income quantiles have a more significant impact than higher quantiles. The Granger causality test shows bidirectional causality between the ecological footprint and exogenous factors: eco-technologies, gross domestic product/capita, renewable energy, urbanization, and imports.
Open Access: Yes
Inelastic tunneling through normal and superconducting junctions in the presence of a photonic bath within the Lindbladian formalism
Publication Name: Physical Review A
Publication Date: 2024-07-01
Volume: 110
Issue: 1
Page Range: Unknown
Description:
An electron tunneling across a junction integrated into an electric circuit can generate an excitation in the photonic field (electromagnetic environment) and lose energy in the process. Such inelastic tunneling of particles is commonly described using the P(E) theory. In the conventional approach to this theory, the tunneling rate and the electric current through the junction are derived using Fermi's golden rule and by averaging over the environmental photonic degrees of freedom. In this work, we address the same problem of inelastic tunneling due to photonic environment in Lindbladian formalism and we present how the photonic degrees of freedom are traced out in the quantum master equation approach. The resulting quantum master equation is parametrized by the same P(E) function and enables us to obtain not only the electric current but various other quantities, for instance, the heat current, in a systematic and convenient way. We also demonstrate that the Lindbladian formalism provides a comprehensive description of Bogoliubov quasiparticle tunneling through superconducting junctions and that it properly accounts for the coherence factors. The coherence factors become important if the normal-state density of states is particle-hole asymmetric.
Open Access: Yes
Dietary inclusion of defatted silkworm (Bombyx mori L.) pupa meal in broiler chickens: phase feeding effects on nutritional and sensory meat quality
Publication Name: Poultry Science
Publication Date: 2024-07-01
Volume: 103
Issue: 7
Page Range: Unknown
Description:
The present experiment was conducted to test the effect of a 4% defatted silkworm (Bombyx mori) pupae meal (SWM) incorporation into chickens’ diets at different growth phases on meat quality characteristics and sensory traits. Ninety ROSS 308 day-old male broiler chickens were randomly assigned to 3 dietary groups, with 5 replicated pens/diet: the first group received a control (C) diet throughout the growing period of 42 d, the second group received a diet with 4% SWM (SWM1) during the starter phase (1–10 d) and the C diet up to slaughter, whereas the third group was fed the C diet during the starter phase and 4% SWM during the grower and finisher phases (SWM2). Diets were isonitrogenous and isoenergy, and birds had free access to feed and water throughout the experimental trial. At 42 d of age, 15 chickens/treatment were slaughtered at a commercial abattoir. Fatty acid (FA) and amino acid (AA) profiles and contents of meat, as well as its oxidative status, were determined in both breast and leg meat cuts. Also, a descriptive sensory analysis was performed on breast meat by trained panelists. Results highlighted that the SWM2 treatment increased the n-3 proportion and content in both breast and leg meat, thereby improving the omega-6/omega-3 (n-6/n-3) ratio in both cuts (P < 0.001). However, the dietary treatment had no significant effect on the oxidative status of either breast or leg meat (P > 0.05). The SWM had a limited impact on overall sensory traits of breast meat, but it contributed to improve meat tenderness in SWM-fed chickens (P < 0.01). Furthermore, SWM1 meat exhibited higher juiciness (P < 0.05) and off flavor intensity (P < 0.05) compared to the control meat. Overall, the present experiment indicated that defatted SWM holds promise as an alternative ingredient in chicken rations, ensuring satisfactory meat quality. Furthermore, administering SWM during the grower-finisher phase demonstrated beneficial effects on meat healthiness, ultimately enhancing n-3 fatty acids content and reducing the n-6/n-3 ratio.
Open Access: Yes
The structure–activity relationship of marine peptides: a review
Publication Name: International Journal of Food Science and Technology
Publication Date: 2024-07-01
Volume: 59
Issue: 7
Page Range: 4437-4445
Description:
Oceans cover over 70% of the Earth's surface and provide home to structurally diverse marine organisms. These creatures contribute to more than half of the biodiversity of the world and produce several bioactive molecules, including peptides. In the past years, scientific research has been focused on the compositions, sequences and structural features of marine-derived peptides. Based on their amino acid sequences, they have demonstrated a wide range of biological functions, including antithrombotic, antihypertensive, anticancer, antioxidant, antimicrobial, antiageing, anti-inflammatory, immunomodulatory and other multifunctional activities that are based on their structure, hydrophobicity, binding affinity, charge and other factors. This review focuses on novel techniques used to produce marine peptides and explores the structure–function relationships of these peptides derived from representative phyla, namely Cnidaria, Annelida, Mollusca, Arthropoda, Chordata, Echinodermata and Porifera. Furthermore, notable considerations regarding the structure–function basis of marine peptide applications are discussed.
Open Access: Yes
DOI: 10.1111/ijfs.17248
