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Taxonomy of centralization in public blockchain systems: asystematic literature review
No full textBitcoin introduced delegation of control over a monetary system from a select few to all who participate in that system. This delegation is known as the decentralization of controlling power and is a powerful security mechanism for the ecosystem. After the introduction of Bitcoin, the field of cryptocurrency has seen widespread attention from industry and academia, so much so that the original novel contribution of Bitcoin, i.e., decentralization, may be overlooked, due to decentralizations’ assumed fundamental existence for the functioning of such crypto-assets. However, recent studies have observed a trend of increased centralization in cryptocurrencies such as Bitcoin and Ethereum. As this increased centralization has an impact the security of the blockchain, it is crucial that it is measured, towards adequate control. This research derives an initial taxonomy of centralization present in decentralized blockchains through rigorous synthesis using a systematic literature review. This is followed by iterative refinement
through expert interviews. We systematically analyzed 89 research papers published between 2009 and 2019. Our study contributes to the existing body of knowledge by highlighting the multiple definitions and measurements of centralization in the literature. We identify different aspects of centralization and propose an encompassing taxonomy of centralization concerns. This taxonomy is based on empirically observable and measurable characteristics. It consists of 13 aspects of centralization, classified over six architectural layers: Governance, Network, Consensus, Incentive, Operational, and Application. We also discuss how the implications of centralization can vary depending on the aspects studied. We believe that this review and taxonomy provides a comprehensive overview of centralization in decentralized blockchains involving various conceptualizations and measure
Mixing and mixed layer depths in the ocean
No full textThe ocean surface boundary layer (OSBL) is one of the largest global regulators of climate. There are two definitions associated with its depth: the mixed layer depth (MLD) and the mixing layer depth (XLD). The former is estimated using
vertical profiles of temperature and density, and the latter using measurements of the dissipation rate of turbulent kinetic energy. The relationship between the XLD and MLD has not been extensively studied in the past, since this requires
specialized instruments which allow simultaneous measurements of the ocean state variables and turbulence across the full depth of the OSBL. The overarching objective of this thesis is to study the variability of the XLD and MLD under different conditions. To achieve this, different estimates of the MLD and XLD are applied to vertical profiles derived from an autonomous vertical profiler (ASIP) deployed in two different cruises in the North Atlantic. It was found
that the MLD criteria differ between themselves when stratification is weaker and the transition between the mixed layer and the pycnocline is not well defined. On the contrary, the XLD criteria had a better agreement between themselves, and a new method was proposed to improve its estimation. Given the close link found between the XLD and the sources of ocean turbulence, a scaling for the XLD was tested dividing the ocean into different mixing regimes according to the ratio between the Monin-Obukhov length, the MLD, and the surface net heat fluxes. The results found using ASIP data were extrapolated to build a climatology of the upper mixing using reanalysis data from ERA5 and ARGO profiles during a period of 10 years (2009-2018). Significant differences between the MLD and the XLD climatology were found during this process
The use of Net Promoter Score (NPS) to predict sales growth: insights from an empirical investigation
No full textNet Promoter Score (NPS) has been widely adopted by managers as a measure of customer mindset and predictor of sales growth.
Over time, practitioners have evolved the use of NPS from its original purpose as a transaction-based customer loyalty metric,
towards a metric for tracking overall brand health which includes responses from non-customers. Despite enduring managerial
popularity, academics remain skeptical of NPS, citing methodological issues and ongoing concerns with NPS measurement. This
study re-visits the use of NPS as a predictor of sales growth by analyzing data from seven brands operating in the U.S. sportswear
industry, measured over five years. Our results confirm—within the context of our study—that while the original premise of NPS
is reasonable, the methodological concerns raised by academics are valid, and only the more recently developed brand health
measure of NPS (using an all potential customer sample) is effective at predicting future sales growth.PUBLISHEDpeer-reviewe
Hypoxia: Turning vessels into vassals of cancer immunotolerance
No full textHypoxia is a universal feature of solid cancers caused by a mismatch between cellular oxygen supply and consumption. To meet the increased demand for oxygen, hypoxic cancer cells (CCs) induce a multifaceted process known as angiogenesis, wherein new vessels are formed by the sprouting of pre-existing ones. In addition to providing oxygen for growth and an exit route for dissemination, angiogenic vessels and factors are co-opted by CCs to enable the generation of an immunotolerant, hypoxic tumor microenvironment, leading to therapeutic failure and mortality. In this review, we discuss how hypoxia-inducible factors (HIFs), the mechanistic target of rapamycin (mTOR), and the unfolded protein response (UPR) control angiogenic factors serving both vascular and immunomodulatory functions in the tumor microenvironment. Possible therapeutic strategies, wherein targeting oxygen sensing might enhance anti-angiogenic and immunologically-mediated anti-cancer responses, are suggested.University College Dubli
Goat farm variability affects milk Fourier-transform infrared spectra used for predicting coagulation properties
No full textDriven by the large amount of goat milk destined for cheese production, and to pioneer the goat cheese industry, the objective of this study was to assess the effect of farm in predicting goat milk-coagulation and curd-firmness traits via Fourier-transform infrared spectroscopy. Spectra from 452 Sarda goats belonging to 14 farms in central and southeast Sardinia (Italy) were collected. A Bayesian linear regression model was used, estimating all spectral wavelengths\u27 effects simultaneously. Three traditional milk-coagulation properties [rennet coagulation time (min), time to curd firmness of 20 mm (min), and curd firmness 30 min after rennet addition (mm)] and 3 curd-firmness measures modeled over time [rennet coagulation time estimated according to curd firmness change over time (RCTeq), instant curd-firming rate constant, and asymptotical curd firmness] were considered. A stratified cross validation (SCV) was assigned, evaluating each farm separately (validation set; VAL) and keeping the remaining farms to train (calibration set) the statistical model. Moreover, a SCV, where 20% of the goats randomly taken (10 replicates per farm) from the VAL farm entered the calibration set, was also considered (SCV80). To assess model performance, coefficient of determination (R2VAL) and the root mean squared error of validation were recorded. The R2VAL varied between 0.14 and 0.45 (instant curd-firming rate constant and RCTeq, respectively), albeit the standard deviation was approximating half of the mean for all the traits. Although average results of the 2 SCV procedures were similar, in SCV80, the maximum R2VAL increased at about 15% across traits, with the highest observed for time to curd firmness of 20 mm (20%) and the lowest for RCTeq (6%). Further investigation evidenced important variability among farms, with R2VAL for some of them being close to 0. Our work outlined the importance of considering the effect of farm when developing Fourier-transform infrared spectroscopy prediction equations for coagulation and curd-firmness traits in goats.Università degli Studi di Sassar
National Ecosystem Monitoring Network (NEMN)-Design: Monitoring Air Pollution Impacts across Sensitive Ecosystems
No full textUnder the EC National Emissions Ceiling Directive (NECD 2016/2284), EU member states are required to monitor (Article 9) and report (Article 10.4) air pollution pressure and impacts on ecosystems that are representative of each country’s freshwater, forest, natural and semi-natural habitats. Ireland developed the National Ecosystem Monitoring Network (NEMN) in 2018, with the first data submission on 1st July 2019. In response to recommendations from the EC, Ireland is seeking to improve its NEMN. In this document, we propose methods for monitoring air quality and ecosystem parameters, and for selecting sites to be included in NEMN to improve representative coverage across sensitive habitat types and major pollution gradients. The air pollution impacts of interest are in the first instance those relating to the substances for which reduction commitments are set in Annex II to the NECD (i.e. SO2, NOX, NMVOC and NH3), that is those contributing to acidification and eutrophication of ecosystems, and as precursors of ozone damage to vegetation growth and biodiversity changes. The development of the NEMN is intended to be an iterative process, with incremental improvements over time. The existing network is composed of International Co-operative Programme (ICP) Forests and Waters sites operated under the Air Convention (UN-ECE CLRTAP) and Water Framework Directive (2000/60/EC), respectively. The existing network structure is based on that of ICP Forests, which is composed of two networks with different monitoring intensity, Level II and Level I.Environmental Protection Agenc
Development of a low-power underwater NFC-enabled sensor device for seaweed monitoring
No full textAquaculture farming faces challenges to increase production while maintaining welfare of livestock, efficiently use of resources, and being environmentally sustainable. To help overcome these challenges, remote and real-time monitoring of the environmental and biological conditions of the aquaculture site is highly important. Multiple remote monitoring solutions for investigating the growth of seaweed are available, but no integrated solution that monitors different biotic and abiotic factors exists. A new integrated multi-sensing system would reduce the cost and time required to deploy the system and provide useful information on the dynamic forces affecting the plants and the associated biomass of the harvest. In this work, we present the development of a novel miniature low-power NFC-enabled data acquisition system to monitor seaweed growth parameters in an aquaculture context. It logs temperature, light intensity, depth, and motion, and these data can be transmitted or downloaded to enable informed decision making for the seaweed farmers. The device is fully customisable and designed to be attached to seaweed or associated mooring lines. The developed system was characterised in laboratory settings to validate and calibrate the embedded sensors. It performs comparably to commercial environmental sensors, enabling the use of the device to be deployed in commercial and research settings
Monolithic metal–organic frameworks for carbon dioxide separation†
No full textCarbon dioxide (CO2) is both a primary contributor to global warming and a major
industrial impurity. Traditional approaches to carbon capture involve corrosive and
energy-intensive processes such as liquid amine absorption. Although adsorptive
separation has long been a promising alternative to traditional processes, up to this
point there has been a lack of appropriate adsorbents capable of capturing CO2 whilst
maintaining low regeneration energies. In the context of CO2 capture, metal–organic
frameworks (MOFs) have gained much attention in the past two decades as potential
materials. Their tuneable nature allows for precise control over the pore size and
chemistry, which allows for the tailoring of their properties for the selective adsorption
of CO2. While many candidate materials exist, the amount of research into material
shaping for use in industrial processes has been limited. Traditional shaping strategies
such as pelletisation involve the use of binders and/or mechanical processes, which can
have a detrimental impact on the adsorption properties of the resulting materials or can
result in low-density structures with low volumetric adsorption capacities. Herein, we
demonstrate the use of a series of monolithic MOFs (monoUiO-66, monoUiO-66-NH2 &
monoHKUST-1) for use in gas separation processes
Physical activity, sedentary behaviour and cardiometabolic health in children, adolescents and young adults
No full textThe overarching aims of this thesis were to: (i) to determine the validity of the activPAL 3
micro for measuring physical activity (PA) intensity in adolescents; (ii) to quantify differences
in free-living activity behaviours across cohorts of children, adolescents and young adults using
the activPAL 3 micro; (iii) to examine the associations between free-living activity behaviours
and indices of cardiometabolic health in a representative sample of Irish adolescents; and, (iv)
to model the effects of reallocating time between activity behaviours on cardiometabolic health
markers in Irish adolescents.
The activPAL monitor is the world’s first single-site instrument validated to accurately
measure sedentary time, standing time and postural changes. Despite this, the device output
has been limited to classifying an individual’s free-living activity into periods of sitting/lying,
stepping and standing. A count-to-activity threshold for the activPAL 3 micro was developed
and validated to provide accurate measures of MVPA and subsequently LIPA.
Habitual activity behaviours were assessed within cohorts of children, adolescents and
young adults (N = 194). Waking sedentary time, MVPA and prolonged sedentary bouts
increased across the different aged cohorts. Standing time differed significantly, while LIPA
and the time spent in short sedentary bouts decreased. The level, duration and pattern of
habitual activity behaviours differed significantly between weekdays and weekend days and
between school/university hours and out-of-school/university hours.
Free-living activity behaviours and cardiometabolic health indices were examined in a
representative sample of 15 to 18-year-old Irish adolescents (N = 222). Sedentary waking time
was detrimentally associated with diastolic blood pressure, LDL-C and glucose. Increased
standing time was only associated with lower systolic and diastolic blood pressure. Increased
LIPA time was beneficially associated with sum-of-skinfold thickness, handgrip strength,
cardiorespiratory fitness, diastolic blood pressure, total cholesterol and triglycerides and
negatively associated with waist-to-hip ratio and HDL-C. Sedentary Bouts < 20 minutes were
beneficially associated handgrip strength and cardiovascular fitness and negatively associated
with waist-hip-ratio. Sedentary bouts > 60 minutes were detrimentally associated with diastolic
blood pressure. Reallocating the time spent in one activity behaviour with another significantly
influenced the cardiometabolic health indices.
The evidence presented in this thesis highlights the importance of increasing LIPA in
addition to MVPA to improve and maintain adolescent cardiometabolic health. Future
interventional and longitudinal research should be conducted to determine the implication of
replacing sedentary time with LIPA, with the aim of informing public health initiatives and
future PA guidelines
The Sustainable Intensification of the Irish Dairy Sector
No full textThe concept of sustainability is one of the forefront issues in global agricultural production at
present, given mounting pressure to increase food production in both a socially responsible
and environmentally friendly way. From an Irish perspective the sustainable intensification
of agriculture is of particular relevance given ambitious targets to increase milk production
by 50 percent by 2020, in the context of European milk quota removal. Alongside this,
environmental targets may be specified, meaning that expansion would have to be achieved
in a sustainable way. To evaluate dairy farm-level sustainability a series of indicators are
developed here using Teagasc National Farm Survey FADN (Farm Accountancy Data
Network) data for Ireland from 2012. Three dimensions, reflecting the multifaceted nature of
sustainability (economic, environmental and social) are considered. Given the environmental
challenges inherent in the sustainable intensification of agriculture, it is encouraging to
observe that the more intensive, top performing farms (in an economic sense) emit relatively
less greenhouse gases when compared to their less intensive counterparts. Conversely, the
better performing farms in economic terms tend to have higher nitrogen surplus per hectare
on average. This is consistent with their higher rates of production intensity but poses a
challenge in terms of sustainable expansion. That said this analysis demonstrates that the
nitrogen use efficiency of milk production is positively correlated with economic
performance, with more intensive farms producing relatively more milk per kg of nitrogen
surplus. From a social perspective demography also tends to be correlated with economic
performance. These indicators allow for the continued assessment of the sustainability status
of Irish farming