1,917 research outputs found
Modelling electromagnetic radiation from digital electronic systems by means of the finite difference time domain method
Understanding nutrition students' knowledge, perceived barriers and their views on the future role of nutritionists regarding sustainable diets
Nutrition professionals are important stakeholders in sustainable food systems with skills to promote the connection between health, food production, environment, culture and economics. Higher education institutions are increasingly recognising the importance of teaching about sustainability, yet there exists a gap in the literature detailing the awareness of sustainability issues by nutrition students. This study aimed to ascertain the level of knowledge of sustainable diets (SDs), the perceived barriers to their adoption in their own diets, students' experience of universityâbased teaching about SDs and their views on the future role of the nutrition profession in relation to SD amongst nutrition students on Association for Nutrition (AfN)âaccredited degrees. The study assessed environmental and sustainable food literacy (SFL) through an online questionnaire and explored the issues in more detail in virtual or faceâtoâface interviews in 2019. Quantitative data were analysed using descriptive statistics (KruskalâWallis, JonckheereâTerpstra, independent tâtest, Spearman, Pearson Correlations). Qualitative data were analysed using the Braun and Clark (2006) sixâstep approach to thematic analysis. The questionnaire responses (n=â51) represented 17 AfNâaccredited undergraduate courses (35% of AfNâaccredited universities in 2019). The majority (76%) of students had received an introduction, partaken in a module or received teaching on SDs throughout their whole degree. Students were predominantly environmentally literate, yet had a fragmented understanding of SDs, focusing on the environmental aspects of SDs. There was no correlation between SFL and reported sustainability content of university courses, highlighting a need for more effective teaching on sustainability topics. Additionally, no relationship between selfâreported diet intake and SFL was found. Students identified a lack of knowledge and education as barriers preventing them from adopting sustainable practices in the present and future. To integrate sustainability into their future practice more consistently and effectively, nutrition students require more structured, holistic sustainability education and knowledge
Silicon photonic Mach Zehnder modulators for next-generation short-reach optical communication networks
Communication traffic grows relentlessly in todayâs networks, and with ever more machines connected to the network, this trend is set to continue for the foreseeable future. It is widely accepted that increasingly faster communications are required at the point of the end users, and consequently optical transmission plays a progressively greater role even in short- and medium-reach networks. Silicon photonic technologies are becoming increasingly attractive for such networks, due to their potential for low cost, energetically efficient, high-speed optical components. A representative example is the silicon-based optical modulator, which has been actively studied. Researchers have demonstrated silicon modulators in different types of structures, such as ring resonators or slow light based devices. These approaches have shown remarkably good performance in terms of modulation efficiency, however their operation could be severely affected by temperature drifts or fabrication errors. Mach-Zehnder modulators (MZM), on the other hand, show good performance and resilience to different environmental conditions. In this paper we present a CMOS-compatible compact silicon MZM. We study the application of the modulator to short-reach interconnects by realizing data modulation using some relevant advanced modulation formats, such as 4-level Pulse Amplitude Modulation (PAM-4) and Discrete Multi-Tone (DMT) modulation and compare the performance of the different systems in transmission
Support for the Slope Sea as a major spawning ground for Atlantic bluefin tuna: evidence from larval abundance, growth rates, and particle-tracking simulations
© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hernandez, C. M., Richardson, D. E., Rypina, I. I., Chen, K., Marancik, K. E., Shulzitski, K., & Llopiz, J. K. Support for the Slope Sea as a major spawning ground for Atlantic bluefin tuna: evidence from larval abundance, growth rates, and particle-tracking simulations. Canadian Journal of Fisheries and Aquatic Sciences, 79(5), (2021): 814-824, https://doi.org/10.1139/cjfas-2020-0444.Atlantic bluefin tuna (Thunnus thynnus) are commercially and ecologically valuable, but management is complicated by their highly migratory lifestyle. Recent collections of bluefin tuna larvae in the Slope Sea off northeastern United States have opened questions about how this region contributes to population dynamics. We analyzed larvae collected in the Slope Sea and the Gulf of Mexico in 2016 to estimate larval abundance and growth rates and used a high-resolution regional ocean circulation model to estimate spawning locations and larval transport. We did not detect a regional difference in growth rates, but found that Slope Sea larvae were larger than Gulf of Mexico larvae prior to exogenous feeding. Slope Sea larvae generally backtracked to locations north of Cape Hatteras and would have been retained within the Slope Sea until the early juvenile stage. Overall, our results provide supporting evidence that the Slope Sea is a major spawning ground that is likely to be important for population dynamics. Further study of larvae and spawning adults in the region should be prioritized to support management decisions.Ship time was supported by NOAA, the Bureau of Ocean Energy Management, and the US Navy through interagency agreements for Atlantic Marine Assessment Program for Protected Species (AMAPPS). CMH and JKL received funding from the Woods Hole Oceanographic Institutionâs Ocean Life Institute (#13080700) and Academic Programs Office. CMH was additionally supported by the Adelaide and Charles Link Foundation and the J. Seward Johnson Endowment in support of the Woods Hole Oceanographic Institutionâs Marine Policy Center. IIR, KC, and JKL were supported by a US National Science Foundation (NSF) grant (OCE-1558806). JKL was additionally supported by the Lenfest Fund for Early Career Scientists and the Early Career Scientist Fund at Woods Hole Oceanographic Institution
Visual characterization of associative quasitrivial nondecreasing operations on finite chains
In this paper we provide visual characterization of associative quasitrivial
nondecreasing operations on finite chains. We also provide a characterization
of bisymmetric quasitrivial nondecreasing binary operations on finite chains.
Finally, we estimate the number of functions belonging to the previous classes.Comment: 25 pages, 18 Figure
Adolescentsâ responses to the promotion and flavouring of e-cigarettes
Objectives
The purpose of the study is to examine adolescentsâ awareness of e-cigarette marketing and investigate the impact of e-cigarette flavour descriptors on perceptions of product harm and user image.
Methods
Data come from the 2014 Youth Tobacco Policy Survey, a cross-sectional in-home survey conducted with 11â16 year olds across the UK (n = 1205). Adolescentsâ awareness of e-cigarette promotion, brands, and flavours was assessed. Perceptions of product harm, and likely user of four examples of e-cigarette flavours was also examined.
Results
Some participants had tried e-cigarettes (12 %) but regular use was low (2 %) and confined to adolescents who had also smoked tobacco. Most were aware of at least one promotional channel (82 %) and that e-cigarettes came in different flavours (69 %). Brand awareness was low. E-cigarettes were perceived as harmful (M = 3.54, SD = 1.19) but this was moderated by product flavours. Fruit and sweet flavours were perceived as more likely to be tried by young never smokers than adult smokers trying to quit (p < 0.001).
Conclusions
There is a need to monitor the impact of future market and regulatory change on youth uptake and perceptions of e-cigarettes
Intelligent Method for Diagnosing Structural Faults of Rotating Machinery Using Ant Colony Optimization
Structural faults, such as unbalance, misalignment and looseness, etc., often occur in the shafts of rotating machinery. These faults may cause serious machine accidents and lead to great production losses. This paper proposes an intelligent method for diagnosing structural faults of rotating machinery using ant colony optimization (ACO) and relative ratio symptom parameters (RRSPs) in order to detect faults and distinguish fault types at an early stage. New symptom parameters called ârelative ratio symptom parametersâ are defined for reflecting the features of vibration signals measured in each state. Synthetic detection index (SDI) using statistical theory has also been defined to evaluate the applicability of the RRSPs. The SDI can be used to indicate the fitness of a RRSP for ACO. Lastly, this paper also compares the proposed method with the conventional neural networks (NN) method. Practical examples of fault diagnosis for a centrifugal fan are provided to verify the effectiveness of the proposed method. The verification results show that the structural faults often occurring in the centrifugal fan, such as unbalance, misalignment and looseness states are effectively identified by the proposed method, while these faults are difficult to detect using conventional neural networks
Characterization of Shewanella oneidensis MtrC: a cell-surface decaheme cytochrome involved in respiratory electron transport to extracellular electron acceptors
MtrC is a decaheme c-type cytochrome associated with the outer cell membrane of Fe(III)-respiring species of the Shewanella genus. It is proposed to play a role in anaerobic respiration by mediating electron transfer to extracellular mineral oxides that can serve as terminal electron acceptors. The present work presents the first spectropotentiometric and voltammetric characterization of MtrC, using protein purified from Shewanella oneidensis MR-1. Potentiometric titrations, monitored by UVâvis absorption and electron paramagnetic resonance (EPR) spectroscopy, reveal that the hemes within MtrC titrate over a broad potential range spanning between approximately +100 and approximately -500 mV (vs. the standard hydrogen electrode). Across this potential window the UVâvis absorption spectra are characteristic of low-spin c-type hemes and the EPR spectra reveal broad, complex features that suggest the presence of magnetically spin-coupled low-spin c-hemes. Non-catalytic protein film voltammetry of MtrC demonstrates reversible electrochemistry over a potential window similar to that disclosed spectroscopically. The voltammetry also allows definition of kinetic properties of MtrC in direct electron exchange with a solid electrode surface and during reduction of a model Fe(III) substrate. Taken together, the data provide quantitative information on the potential domain in which MtrC can operate
Early stressful experiences are associated with reduced neural responses to naturalistic emotional and social content in children
How do childrenâs experiences relate to their naturalistic emotional and social processing? Because children can struggle with tasks in the scanner, we collected fMRI data while 4-to-11-year-olds watched a short film with positive and negative emotional events, and rich parent-child interactions (n = 70). We captured broad, normative stressful experiences by examining socioeconomic status (SES) and stressful life events, as well as childrenâs more proximal experiences with their parents. For a sub-sample (n = 30), parenting behaviors were measured during a parent-child interaction, consisting of a picture book, a challenging puzzle, and free play with novel toys. We characterized positive parenting behaviors (e.g., warmth, praise) and negative parenting behaviors (e.g., harsh tone, physical control). We found that higher SES was related to greater activity in medial orbitofrontal cortex during parent-child interaction movie events. Negative parenting behaviors were associated with less activation of the ventral tegmental area and cerebellum during positive emotional events. In a region-of-interest analysis, we found that stressful life events and negative parenting behaviors were associated with less activation of the amygdala during positive emotional events. These exploratory results demonstrate the promise of using movie fMRI to study how early experiences may shape emotional, social, and motivational processes
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