963 research outputs found
TROPIX Power System Architecture
This document contains results obtained in the process of performing a power system definition study of the TROPIX power management and distribution system (PMAD). Requirements derived from the PMADs interaction with other spacecraft systems are discussed first. Since the design is dependent on the performance of the photovoltaics, there is a comprehensive discussion of the appropriate models for cells and arrays. A trade study of the array operating voltage and its effect on array bus mass is also presented. A system architecture is developed which makes use of a combination of high efficiency switching power convertors and analog regulators. Mass and volume estimates are presented for all subsystems
Environmental impact assessment of online advertising
There are no commonly agreed ways to assess the total energy consumption of the Internet. Estimating the Internet's energy footprint is challenging because of the interconnectedness associated with even seemingly simple aspects of energy consumption.
The first contribution of this paper is a common modular and layered framework, which allows researchers to assess both energy consumption and CO2e emissions of any Internet service. The framework allows assessing the energy consumption depending on the research scope and specific system boundaries. Further, the proposed framework allows researchers without domain expertise to make such an assessment by using intermediate results as data sources, while analyzing the related uncertainties. The second contribution is an estimate of the energy consumption and CO2e emissions of online advertising by utilizing our proposed framework. The third contribution is an assessment of the energy consumption of invalid traffic associated with online advertising. The second and third contributions are used to validate the first.
The online advertising ecosystem resides in the core of the Internet, and it is the sole source of funding for many online services. Therefore, it is an essential factor in the analysis of the Internet's energy footprint. As a result, in 2016, online advertising consumed 20–282 TWh of energy. In the same year, the total infrastructure consumption ranged from 791 to 1334 TWh. With extrapolated 2016 input factor values without uncertainties, online advertising consumed 106 TWh of energy and the infrastructure 1059 TWh. With the emission factor of 0.5656 kg CO2e/kWh, we calculated the carbon emissions of online advertising, and found it produces 60 Mt CO2e (between 12 and 159 Mt of CO2e when considering uncertainty). The share of fraudulent online advertising traffic was 13.87 Mt of CO2e emissions (between 2.65 and 36.78 Mt of CO2e when considering uncertainty).
The global impact of online advertising is multidimensional. Online advertising affects the environment by consuming significant amounts of energy, leading to the production CO2e emissions. Hundreds of billions of ad dollars are exchanged yearly, placing online advertising in a significant role economically. It has become an important and acknowledged component of the online-bound society, largely due to its integration with the Internet and the amount of revenue generated through it
A mixed method evaluation of a theory based intervention to reduce sedentary behaviour in contact centres- the stand up for health stepped wedge feasibility study
Copyright: \ua9 2023 Sivaramakrishnan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. INTRODUCTION: Contact centres have higher levels of sedentary behaviour than other office-based workplaces. Stand Up for Health (SUH) is a theory-based intervention developed using the 6SQuID framework to reduce sedentary behaviour in contact centre workers. The aim of this study was to test acceptability and feasibility of implementing SUH in UK contact centres. METHODS: The study was conducted in 2020-2022 (pre COVID and during lockdown) and used a stepped-wedge cluster randomised trial design including a process evaluation. The intervention included working with contact centre managers to develop and implement a customised action plan aligning with SUH\u27s theory of change. Workplace sedentary time, measured using activPAL™ devices, was the primary outcome. Secondary outcomes included productivity, mental wellbeing, musculoskeletal health and physical activity. Empirical estimates of between-centre standard deviation and within-centre standard deviation of outcomes from pre-lockdown data were calculated to inform sample size calculations for future trials. The process evaluation adopted the RE-AIM framework to understand acceptability and feasibility of implementing the intervention. Interviews and focus groups were conducted with contact centre employees and managers, and activity preferences were collected using a questionnaire. RESULTS: A total of 11 contact centres participated: 155 employees from 6 centres in the pre-lockdown data collection, and 54 employees from 5 centres post-lockdown. Interviews and focus groups were conducted with 33 employees and managers, and 96 participants completed an intervention activity preference questionnaire. Overall, the intervention was perceived as acceptable and feasible to deliver. Most centres implemented several intervention activities aligned with SUH\u27s theory of change and over 50% of staff participated in at least one activity (pre-lockdown period). Perceived benefits including reduced sedentary behaviour, increased physical activity, and improved staff morale and mood were reported by contact centre employees and managers. CONCLUSIONS: SUH demonstrates potential as an appealing and acceptable intervention, impacting several wellbeing outcomes. TRIAL REGISTRATION: The trial has been registered on the ISRCTNdatabase: http://www.isrctn.com/ISRCTN11580369
LAS inhibition of diffusion and uptake of tritiated uridine during teleost embryogenesis
Functional distinctions between two isoforms of WNT5A
WNT5A is a secreted protein ligand with important roles in development, adult tissue homeostasis, and many basic cellular functions. In cancers, aberrant WNT5A signaling is often observed. This study focused on potential functional differences between two isoforms of this protein, on potential signaling differences between these two isoforms, and on differential expression of these isoforms in the context of mouse embryonic development. This study found that these isoforms both had no effect on either cellular migration or invasion in HCT116, contrary to reports published in the literature. This study also found that both these isoforms had no detectable effect on activation of terminal effector molecules in the PCP/CE pathway or in the Wnt/Ca2+ pathway. In a murine model of embryonic development, we observed that WNT5A isoforms were differentially regulated. Overall, the findings of this study suggest that WNT5A encodes functionally distinct protein isoforms which may play a role in enabling the orchestration of a complex series of biological events during embryonic development
The token’s secret: the two-faced financial incentive of the token economy
Multi-sided platforms are omnipresent in today’s digital world. However, establishing a platform includes challenges: The platform utility usually increases with the number of participants. At an early stage, potential participants expect the platform utility to be low and lack an incentive to join (i.e., “chicken and egg” problem). Blockchain-enabled utility tokens hold the promise to overcome this problem. They supposedly provide a suitable financial incentive for their owners to join the platform as soon as possible. In the first half of 2018, investors seemed to believe in the presumption and spent more than US$ 17.6 billion in token sales. To date, we know little about this financial incentive in the context of the token economy. For this purpose, we model the token value development and the associated incentives in a multi-sided blockchain-enabled platform. The resulting findings suggest that blockchain-enabled utility tokens can help to overcome the “chicken and egg” problem. However, these tokens lead to contradictory incentives for platform participants, and can even inhibit platform usage. The contribution of our work is twofold: First, we develop one of the first models for token value development. Second, our research contributes to a deeper understanding of the utility token’s financial incentive
Preemptive Pregabalin in Children and Adolescents Undergoing Posterior Instrumented Spinal Fusion A Double-Blinded, Placebo-Controlled, Randomized Clinical Trial
Background: Pregabalin as part of a multimodal pain-management regimen has been shown to reduce opioid consumption after spinal surgery in adults but it is unclear whether this is also true in adolescents. Pregabalin has been found to have neuroprotective effects and therefore could have a positive impact on pain after spinal deformity surgery. We conducted a randomized, double-blinded, placebo-controlled clinical trial of adolescent patients undergoing spinal fusion to evaluate the short-term effects of pregabalin on postoperative pain and opioid consumption. Methods: Adolescents with adolescent idiopathic scoliosis, Scheuermann kyphosis, or spondylolisthesis who were scheduled for posterior spinal fusion with all-pedicle-screw instrumentation were randomized to receive either pregabalin (2 mg/kg twice daily) or placebo preoperatively and for 5 days after surgery. The patients ranged from 10 to 21 years of age. The primary outcome was total opioid consumption as measured with use of patient-controlled analgesia. Postoperative pain scores and opioid-related adverse effects were evaluated. Results: Sixty-three of 77 eligible patients were included and analyzed. Cumulative oxycodone consumption per kilogram did not differ between the study groups during the first 48 hours postoperatively, with a median of 1.44 mg/kg (95% confidence interval [CI],1.32 to 1.67 mg/kg) in the pregabalin group and 1.50 mg/kg (95% CI, 1.39 to 1.79 mg/kg) in the placebo group (p = 0.433). A subgroup analysis of 51 patients with adolescent idiopathic scoliosis showed the same result, with a mean of 1.45 mg/kg (95% CI, 1.24 to 1.65 mg/kg) in the pregabalin group and 1.59 mg/kg (95% CI, 1.37 to 1.82 mg/kg) in the placebo group (p = 0.289). Total oxycodone consumption per hour (mg/kg/hr) was not different between the groups over the time points (p = 0.752). The postoperative pain scores did not differ significantly between the groups (p = 0.196). Conclusions: The use of perioperative pregabalin does not reduce the postoperative opioid consumption or pain scores in adolescents after posterior spinal fusion surgery.Peer reviewe
KELT-3b: A Hot Jupiter Transiting A V=9.8 Late-F Star
We report the discovery of KELT-3b, a moderately inflated transiting hot Jupiter with a mass of 1.477(-0.067)(+0.066) M-J, radius of 1.345 +/- 0.072 R-J, and an orbital period of 2.7033904 +/- 0.000010 days. The host star, KELT-3, is a V = 9.8 late F star with M-* = 1.278(-0.061)(+0.063) M-circle dot, R-* = 1.472(-0.067)(+0.065) R-circle dot, T-eff = 6306(-49)(+50) K, log(g) = 4.209(-0.031)(+0.033), and [Fe/H] = 0.044(-0.082)(+0.080), and has a likely proper motion companion. KELT-3b is the third transiting exoplanet discovered by the KELT survey, and is orbiting one of the 20 brightest known transiting planet host stars, making it a promising candidate for detailed characterization studies. Although we infer that KELT-3 is significantly evolved, a preliminary analysis of the stellar and orbital evolution of the system suggests that the planet has likely always received a level of incident flux above the empirically identified threshold for radius inflation suggested by Demory & Seager
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