60419 research outputs found
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Massive MIMO in Mobile Networks: Self-Calibration with Channel Estimation Error
No full textTime-division-duplexing (TDD) massive multiple-input multiple-output (MIMO) systems will play a crucial role in the deployment of emerging mobile networks in 5G and beyond. Such systems heavily rely on the reciprocity-based channel estimation for its scalability. However, the imperfect channel reciprocity, mainly caused by radio-frequency mismatches among the base station antennas, can contaminate the estimate of the effective channel response thus become a performance-limiting factor. In practice, self-calibration schemes are often applied to compensate for this type of imperfections. This work investigates two self-calibration schemes, namely relative calibration and inverse calibration. Considering a TDD massive multi-user MIMO system in the presence of both channel reciprocity error and imperfect channel estimation, we derive closed-form expressions for the receive mean-square error and provide an in-depth comparative analysis of the post-equalisation performance of two calibration schemes. The proposed analytical results are verified via Monte-Carlo simulations
Engineering heterogenous catalysts for chemical CO₂ utilization: Lessons from thermal catalysis and advantages of yolk@shell structured nanoreactors
No full textThe development of catalytic materials for the recycling CO₂ through a myriad of available processes is an attractive field, especially given the current climate change. While there is increasing publication in this field, the reported catalysts rarely deviate from the traditionally supported metal nanoparticle morphology, with the most simplistic method of enhancement being the addition of more metals to an already complex composition. Encapsulated catalysts, especially yolk@shell catalysts with hollow voids, offer answers to the most prominent issues faced by this field, coking and sintering, and further potential for more advanced phenomena, for example, the confinement effect, to promote selectivity or offer greater protection against coking and sintering. This work serves to demonstrate the current position of catalyst development in the fields of thermal CO₂ reforming and hydrogenation, summarizing the most recent work available and most common metals used for these reactions, and how yolk@shell catalysts can offer superior performance and survivability in thermal CO₂ reforming and hydrogenation to the more traditional structure. Furthermore, this work will briefly demonstrate the bespoke nature and highly variable yolk@shell structure. Moreover, this review aims to illuminate the spatial confinement effect and how it enhances yolk@shell structured nanoreactors is presented
Evaluating implementation strategies for essential newborn care interventions in low- and low middle-income countries: a systematic review
No full textNeonatal mortality remains a significant health problem in low income settings. Low-cost essential newborn care (ENC) interventions with proven efficacy and cost-effectiveness exist but have not reached high coverage (≥90%). Little is known about the strategies used to implement these interventions or how they relate to improved coverage. We conducted a systematic review of implementation strategies and implementation outcomes for ENC in low- and low middle-income countries capturing evidence from five medical and global health databases from 1990-2018. We included studies of implementation of delayed cord clamping, immediate drying, skin-to-skin contact, and/or early initiation of breastfeeding implemented in the first hour (facility-based studies) or the first day (community-based studies) of life. Implementation strategies and outcomes were categorised according to published frameworks (Powell et al (2015): Expert Recommendations for Implementing Change (ERIC), Proctor et al (2013): Outcomes for Implementation Research). The relationship between implementation strategies and outcomes was evaluated using standardised mean differences and correlation coefficients. Forty-three papers met inclusion criteria. Interventions included community-based care/health promotion and facility-based support and health care provider training. Included studies used 3-31 implementation strategies, , though the consistency with which strategies were applied was variable. Conduct educational meetings was the most frequently used strategy. Included studies reported 1-4 implementation outcomes with coverage reported most frequently. Heterogeneity was high and no statistically significant association was found between the number of implementation strategies used and coverage of ENC. This review highlights several challenges in learning from implementation of ENC in low- and low middle-income countries, particularly poor description of interventions and implementation outcomes. We recommend use of UK Medical Research Council guidelines (2015) for process evaluations and checklists for reporting implementation studies. Improved reporting of implementation research in this setting is necessary to learn how to improve service delivery and outcomes and thereby reduce neonatal mortality
iCUS: Intelligent CU Size Selection for HEVC Inter Prediction
No full textThe hierarchical quadtree partitioning of Coding Tree Units (CTU) is one of the striking features in HEVC that contributes towards its superior coding performance over its predecessors. However, the brute force evaluation of the quadtree hierarchy using the Rate-Distortion (RD) optimisation, to determine the best partitioning structure for a given content, makes it one of the most time-consuming operations in HEVC encoding. In this context, this paper proposes an intelligent fast Coding Unit (CU) size selection algorithm to expedite the encoding process of HEVC inter-prediction. The proposed algorithm introduces (i) two CU split likelihood modelling and classification approaches using Support Vector Machines (SVM) and Bayesian probabilistic models, and (ii) a fast CU selection algorithm that makes use of both offline trained SVMs and online trained Bayesian probabilistic models. Finally, (iii) a computational complexity to coding efficiency trade-off mechanism is introduced to flexibly control the algorithm to suit different encoding requirements. The experimental results of the proposed algorithm demonstrate an average encoding time reduction performance of 53.46%, 61.15%, and 58.15% for Low Delay B , Random Access , and Low Delay P configurations, respectively, with Bjøntegaard Delta-Bit Rate (BD-BR) losses of 2.35%, 2.9%, and 2.35%, respectively, when evaluated across a wide range of content types and quality levels
Lifestyle: Substance Use—Nicotine, Alcohol and Drugs
No full textUse of substances including alcohol, tobacco and drugs is common in people of reproductive age, can lead to dependence and is a major global health concern. Despite targeted public health policies and campaigns, population surveys (National Institute on Drug Abuse (NIH) 2020; European Drug Report 2019) continue to highlight widespread use of substances, often in combination, which have substantial negative implications for health in general and the potential to harm future generations (Stephenson et al. 2018). Healthcare professionals need to be aware of the complex psychological, physiological and social factors that may be linked to substance use and be prepared to offer counselling and referral for specialist services. Pregnancy, however, can be a ‘window of opportunity’ and a motivating factor for women and their partners to change their behaviour and minimise risk with help to quit or cut down on substance use (Solomon and Quinn 2004). Preconception care offers the opportunity to further reduce risk by helping to modify consumption prior to pregnancy
Love is heterosexual‐by‐default: Cultural heterosexism in default prototypes of romantic love
No full textCultural heterosexist ideologies assume heterosexuality to be the default norm. Four studies investigated when concepts of romantic love are heterosexual‐by‐default (N = 685). In Studies 1–2, participants generated features of romantic love, in general (i.e., the default prototype) or among one of three sexual orientation‐specific couples (lesbian, gay, or heterosexual). Heterosexual‐identified participants’ default prototypes were more similar to heterosexual than same‐gender prototypes (Study 1). Lesbian‐ and gay‐identified participants’ default prototypes were more similar to both heterosexual and gay male than lesbian prototypes, whereas bisexual‐identified participants’ sexual orientation‐specific prototypes were equivalently similar to the default (Study 2). However, heterosexual‐identified participants rated presented features of love similarly across sexual orientation‐specific conditions (Study 3). In a timed feature‐verification task (Study 4), participants categorized fewer peripheral features of romantic love as relevant to same‐gender than mixed‐gender couples. Activating sexual orientation‐specific representations affected subsequent default concepts of romantic love. We discuss implications for heterosexism theories and intervention
Optimisation of Mycobacterium bovis BCG Fermentation and Storage Survival
No full textMycobacterium bovis Bacillus Calmette–Guérin (M. bovis BCG) was generated over a century ago for protection against Mycobacterium tuberculosis (Mtb) and is one the oldest vaccines still in use. The BCG vaccine is currently produced using a pellicle growth method, which is a complex and lengthy process that has been challenging to standardise. Fermentation for BCG vaccine production would reduce the complexity associated with pellicle growth and increase batch to batch reproducibility. This more standardised growth lends itself to quantification of the total number of bacilli in the BCG vaccine by alternative approaches, such as flow cytometry, which can also provide information about the metabolic status of the bacterial population. The aim of the work reported here was to determine which batch fermentation conditions and storage conditions give the most favourable outcomes in terms of the yield and stability of live M. bovis BCG Danish bacilli. We compared different media and assessed growth over time in culture, using total viable counts, total bacterial counts, and turbidity throughout culture. We applied fluorescent viability dyes and flow cytometry to measure real-time within-culture viability. Culture samples were stored in different cryoprotectants at different temperatures to assess the effect of these combined conditions on bacterial titres. Roisin’s minimal medium and Middlebrook 7H9 medium gave comparable, high titres in fermenters. Flow cytometry proved to be a useful tool for enumeration of total bacterial counts and in the assessment of within-culture cell viability and cell death. Of the cryoprotectants evaluated, 5% (v/v) DMSO showed the most significant positive effect on survival and reduced the negative effects of low temperature storage on M. bovis BCG Danish viability. In conclusion, we have shown a reproducible, more standardised approach for the production, evaluation, and storage of high titre, viable, BCG vaccine
Discipline-specific feedback literacies: A framework for curriculum design
No full textFeedback literacy is an important graduate attribute that supports students’ future work capacities. This study aimed to develop a framework through which discipline-specific feedback literacies, as a set of socially-situated skills, can be developed within core curricula. The framework is developed through: a content analysis of National Qualifications Frameworks from six countries and UK Subject Benchmark Statements for multiple disciplines; analysis of indicative subject content for a range of disciplines; and consultation with subject-matter experts. Whilst most of the benchmark statements incorporate the development of feedback literacy skills related to ‘making judgements’, attributes relating to ‘appreciating feedback’ and ‘taking action based on feedback’ are less prevalent. Skills related to ‘managing the affective challenges of feedback’ are most prevalent in documentation for applied disciplines. The resulting empirically-guided curriculum design framework showcases how integrating the development of discipline-specific feedback literacies can be enacted through authentic learning activities and assessment tasks. In terms of implications for practice, the framework represents in concrete terms how discipline-specific feedback literacies can be integrated within higher education curricula. The findings also have implications for policy: by positioning discipline-specific feedback literacies as graduate outcomes, we believe they should be integrated within national qualifications frameworks as crucial skills to be developed through higher education courses. Finally, from a theoretical perspective, we advance conceptions of feedback literacy through a sociocultural approach and propose new directions for research that seek to reconceptualise a singular concept of feedback literacy as multiple feedback literacies that unfold in distinctive ways across disciplines
Complementing theories to explain emotional solidarity
No full textThe purpose of this paper is to test the effect of residents’ attitudes concerning tourism development on support for future tourism development, and ultimately whether such a relationship explains a sense of solidarity with tourists. To do this, a theoretical model was developed and tested based on the social exchange theory and affect theory of exchange. Residents of Antalya, Turkey (N = 660) comprised the sample from which data were collected. Structural equation modelling results demonstrated that residents' attitudes explained 69% of the variance in support for future tourism development, and in turn, this support explained between 25% and 80% of the variance in factors comprising residents’ emotional solidarity with tourists. Findings provide support for the complementary use of the two theories. To round out the paper, implications, limitations and future research are offered
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