Flavivirus genome recoding by codon optimisation confers genetically stable in vivo attenuation in both mice and mosquitoes.

Virus genome recoding is an attenuation method that confers genetically stable attenuation by rewriting a virus genome with numerous silent mutations. Prior flavivirus genome recoding attempts utilised codon deoptimisation approaches. However, these codon deoptimisation approaches act in a species dependent manner and were unable to confer flavivirus attenuation in mosquito cells or in mosquito animal models. To overcome these limitations, we performed flavivirus genome recoding using the contrary approach of codon optimisation. The genomes of flaviviruses such as dengue virus type 2 (DENV2) and Zika virus (ZIKV) contain functional RNA elements that regulate viral replication. We hypothesised that flavivirus genome recoding by codon optimisation would introduce silent mutations that disrupt these RNA elements, leading to decreased replication efficiency and attenuation. We chose DENV2 and ZIKV as representative flaviviruses and recoded them by codon optimising their genomes for human expression. Our study confirms that this recoding approach of codon optimisation does translate into reduced replication efficiency in mammalian, human, and mosquito cells as well as in vivo attenuation in both mice and mosquitoes. In silico modelling and RNA SHAPE analysis confirmed that DENV2 recoding resulted in the extensive disruption of genomic structural elements. Serial passaging of recoded DENV2 resulted in the emergence of rescue or adaptation mutations, but no reversion mutations. These rescue mutations were unable to rescue the delayed replication kinetics and in vivo attenuation of recoded DENV2, demonstrating that recoding confers genetically stable attenuation. Therefore, our recoding approach is a reliable attenuation method with potential applications for developing flavivirus vaccines.

Attenuation of neurovirulence of chikungunya virus by a single amino acid mutation in viral E2 envelope protein.

BACKGROUND: Chikungunya virus (CHIKV) has reemerged as a major public health concern, causing chikungunya fever with increasing cases and neurological complications. METHODS: In the present study, we investigated a low-passage human isolate of the East/ Central/South African (ECSA) lineage of CHIKV strain LK(EH)CH6708, which exhibited a mix of small and large viral plaques. The small and large plaque variants were isolated and designated as CHIKV-SP and CHIKV-BP, respectively. CHIKV-SP and CHIKV-BP were characterized in vitro and in vivo to compare their virus production and virulence. Additionally, whole viral genome analysis and reverse genetics were employed to identify genomic virulence factors. RESULTS: CHIKV-SP demonstrated lower virus production in mammalian cells and attenuated virulence in a murine model. On the other hand, CHIKV-BP induced higher pro-inflammatory cytokine levels, compromised the integrity of the blood-brain barrier, and led to astrocyte infection in mouse brains. Furthermore, the CHIKV-SP variant had limited transmission potential in Aedes albopictus mosquitoes, likely due to restricted dissemination. Whole viral genome analysis revealed multiple genetic mutations in the CHIKV-SP variant, including a Glycine (G) to Arginine (R) mutation at position 55 in the viral E2 glycoprotein. Reverse genetics experiments confirmed that the E2-G55R mutation alone was sufficient to reduce virus production in vitro and virulence in mice. CONCLUSIONS: These findings highlight the attenuating effects of the E2-G55R mutation on CHIKV pathogenicity and neurovirulence and emphasize the importance of monitoring this mutation in natural infections.

The mediating effect of dispositional mindfulness on the association between UPPS-P impulsivity traits and gaming disorder among Asia-Pacific young adults.

BACKGROUND: Little evidence is available to verify the mediating effect of dispositional mindfulness on the association between gaming disorder and various impulsivity traits. The present study aimed to investigate the mediating effect of dispositional mindfulness on the association between the five UPPS-P impulsivity traits and the risk of gaming disorder among young adults. METHODS: It was an inter-regional cross-sectional study using online survey in Australia, Japan, The Philippines and China. Impulsivity measured by the UPPS-P Impulsive Behavior Scale-Short version; dispositional mindfulness measured by the Mindfulness Attention Awareness Scale; and the risk of gaming disorder measured by the Internet Gaming Disorder Scale were collected in the focal regions. Structural equation modeling was performed by SPSS AMOS version 26 to verify the study hypotheses. Bootstrapped 95% confidence interval was reported. Statistical significance was indicated by the p-value below 0.05. RESULTS: Among the 1,134 returned questionnaires, about 40% of them aged 18-20 years and 21-23 years, respectively. 53.8% were male. 40.7% had been playing digital and video games for over 10 years. The prevalence of gaming disorder was 4.32%. The model fitness indices reflected that the constructed model had an acceptable model fit (χ2(118) = 558.994, p < 0.001; χ2/df = 4.737; CFI = 0.924; TLI = 0.890; GFI = 0.948; RMSEA = 0.058; SRMR = 0.0487). Dispositional mindfulness fully mediated the effect of positive urgency and negative urgency on the risk of gaming disorder. The effect of lack of premeditation on the risk of gaming disorder was partially mediated by dispositional mindfulness. However, dispositional mindfulness did not mediate the effect of sensation seeking on the risk of gaming disorder. CONCLUSIONS: The varied associations between dispositional mindfulness and the five impulsivity traits hints that improving some impulsive traits may increase dispositional mindfulness and so lower the risk of gaming disorder. Despite further studies are needed to verify the present findings, it sheds light on the need to apply interventions on gamers based on their impulsivity profile. Interventions targeting at emotion regulation and self-control such as mindfulness-based interventions seem to be effective to help gamers with dominant features of urgency and lack of premeditation only. Other interventions shall be considered for gamers with high sensation seeking tendency to enhance the effectiveness of gaming disorder prevention.

Decision-making experiences related to mastectomy: A descriptive qualitative study.

AIM: To obtain an in-depth understanding of women's decision-making experiences related to mastectomy. DESIGN: A descriptive qualitative interview study. METHODS: Individual semi-structured interviews were conducted face-to-face with 27 Chinese women with breast cancer who underwent mastectomy at two tertiary hospitals in mainland China between September 2020 and December 2021 after obtaining the appropriate ethical approvals. Interviews were conducted in Mandarin. Data were analysed using inductive content analysis. RESULTS: Mean age of participants was 48 years (range 31-70). Most participants had low education, low monthly family income, had a partner and health insurance, had been diagnosed with early breast cancer, and had not undergone reconstructive surgery. Six categories related to decision-making experiences emerged: (1) Emotions affecting decision-making, (2) Information seeking for decision-making, (3) Beliefs about mastectomy and the breast, (4) Participation in decision-making, (5) People who influence decision-making, and (6) Post-decision reflection. Participants did not mention the role of nurses in their decision-making process for mastectomy. CONCLUSIONS: This study adds valuable insights into the limited evidence on women's experience with decision-making about mastectomy from a Chinese perspective, which is important given the continuing high prevalence of mastectomy in many regions. Future studies from other countries and ethnic groups are recommended to gain diverse knowledge. IMPACT: The findings of this study are useful for nurses and other healthcare professionals in the multidisciplinary team to better support women with breast cancer in their decision-making process regarding mastectomy. The findings could inform future interventions to support treatment decision-making and may be relevant to women living in similar socio-medical contexts to those in mainland China. REPORTING METHOD: The study was reported following the Standards for Reporting Qualitative Research checklist. PATIENT OR PUBLIC CONTRIBUTION: No patient or public contribution.

WhatsApp-based intervention for people with type 2 diabetes: A randomized controlled trial.

Diabetes mellitus is a metabolic disease characterized by prolonged elevated blood glucose levels. Diabetes self-management education and support programs are widely used in western countries. The impact of social media education and support interventions such as a WhatsApp-based program and the nurses' role in supporting and implementing this self-management program unclear. Using a WhatsApp-based program, we evaluated the effects of a 6-week program in improving self-efficacy and education among people with type 2 diabetes mellitus in Saudi Arabia. Eligible participants (n = 80) were recruited with the support of nurses into a randomized controlled trial and randomly assigned into self-management intervention and control groups. The intervention group (n = 40) received the self-management program support and the usual care. The control group (n = 40) received only the usual care with nurses' support. Results from generalized estimating equation analysis showed a significant increase in self-efficacy, self-management, and education in the WhatsApp-based intervention support group compared with the control group at 6 and 12 weeks (follow-up). Implementing the program via social media improves self-efficacy. The use of social media platforms should be promoted for global diabetes management.

Challenges, coping and resilience in caring for children with disability among immigrant parents: A mixed methods study.

AIMS: To examine the relationships between challenges, coping and resilience among immigrant parents caring for their children with disabilities; and to explore their coping and resilient experiences and the service centre providers' perspectives on these. DESIGN: A sequential explanatory mixed methods study. METHODS: The participants were recruited from seven centres of disability service in Australia between May 2019 and February 2020. Phase 1 consisted of a cross-sectional survey. Data were collected from 134 immigrant parents. Phase 2 consisted of semi-structured interviews. Data were collected from nine immigrant parents and nine service providers. The findings from each phase were analysed separately and then integrated to answer the research aims. RESULTS: Immigrant parents experienced challenges such as overwhelming caretaking responsibilities, lack of supportive social networks and feeling embarrassment over their children's behaviours. They used a variety of coping strategies, including reframing and mobilizing family to acquire and accept help from others to overcome their challenges. They had positive gains from the parental experience. Immigrant parents had a reasonable level of resilience. Those with a higher level of perceived challenges had a lower level of coping and resilience. Perceived barriers to parental coping included barriers to establishing social networks and utilizing available disability services. Services from competent service providers and the availability of social support networks were factors facilitating immigrant parents' coping. CONCLUSION: Sensitive communication and culturally appropriate care provided by service providers and healthcare professionals can facilitate service utilization and reduce perceived stigma over children with disability. IMPACT: Findings from the study support that special training provided to healthcare providers about the challenges of immigrant parents raising children with disabilities may enhance awareness of the experience of these parents. Information and instrumental support may help to enhance parental coping, reduce isolation and promote their mental health. PATIENT OR PUBLIC CONTRIBUTION: We thank the immigrant parents and the service providers who have been instrumental in the conception of this study.

Classification of Low Earth Orbit (LEO) Resident Space Objects' (RSO) Light Curves Using a Support Vector Machine (SVM) and Long Short-Term Memory (LSTM).

Light curves are plots of brightness measured over time. In the field of Space Situational Awareness (SSA), light curves of Resident Space Objects (RSOs) can be utilized to infer information about an RSO such as the type of object, its attitude, and its shape. Light curves of RSOs in geostationary orbit (GEO) have been a main research focus for many years due to the availability of long time series data spanning hours. Given that a large portion of RSOs are in low Earth orbit (LEO), it is of great importance to study trends in LEO light curves as well. The challenge with LEO light curves is that they tend to be short, typically no longer than a few minutes, which makes them difficult to analyze with typical time series techniques. This study presents a novel approach to observational LEO light curve classification. We extract features from light curves using a wavelet scattering transformation which is used as an input for a machine learning classifier. We performed light curve classification using both a conventional machine learning approach, namely a support vector machine (SVM), and a deep learning technique, long short-term memory (LSTM), to compare the results. LSTM outperforms SVM for LEO light curve classification with a 92% accuracy. This proves the viability of RSO classification by object type and spin rate from real LEO light curves.

A Dual-Purpose Camera for Attitude Determination and Resident Space Object Detection on a Stratospheric Balloon.

Space systems play an integral role in every facet of our daily lives, including national security, communications, and resource management. Therefore, it is critical to protect our valuable assets in space and build resiliency in the space environment. In recent years, we have developed a novel approach to Space Situational Awareness (SSA), in the form of a low-resolution, Wide Field-of-View (WFOV) camera payload for attitude determination and Resident Space Object (RSO) detection. Detection is the first step in tracking, identification, and characterization of RSOs, including natural and artificial objects orbiting the Earth. A space-based dual-purpose camera that can provide attitude information alongside RSO detection can enhance the current SSA technologies which rely on ground infrastructure. A CubeSat form factor payload with real-time attitude determination and RSO detection algorithms was developed and flown onboard the CSA/CNES stratospheric balloon platform in August 2023. Sub-degree pointing information and multiple RSO detections were demonstrated during operation, with opportunities for improvement discussed. This paper outlines the hardware and software architecture, system design methodology, on-ground testing, and in-flight results of the dual-purpose camera payload.

Comparative Analysis of Resident Space Object (RSO) Detection Methods.

In recent years, there has been a significant increase in satellite launches, resulting in a proliferation of satellites in our near-Earth space environment. This surge has led to a multitude of resident space objects (RSOs). Thus, detecting RSOs is a crucial element of monitoring these objects and plays an important role in preventing collisions between them. Optical images captured from spacecraft and with ground-based telescopes provide valuable information for RSO detection and identification, thereby enhancing space situational awareness (SSA). However, datasets are not publicly available due to their sensitive nature. This scarcity of data has hindered the development of detection algorithms. In this paper, we present annotated RSO images, which constitute an internally curated dataset obtained from a low-resolution wide-field-of-view imager on a stratospheric balloon. In addition, we examine several frame differencing techniques, namely, adjacent frame differencing, median frame differencing, proximity filtering and tracking, and a streak detection method. These algorithms were applied to annotated images to detect RSOs. The proposed algorithms achieved a competitive degree of success with precision scores of 73%, 95%, 95%, and 100% and F1 scores of 68%, 77%, 82%, and 79%.

Stratospheric Night Sky Imaging Payload for Space Situational Awareness (SSA).

Space situational awareness (SSA) refers to collecting, analyzing, and keeping track of detailed knowledge of resident space objects (RSOs) in the space environment. With the rapidly increasing number of objects in space, the need for SSA grows as well. Traditional methods rely heavily on imaging RSOs from large, narrow field-of-view (FOV), ground-based telescopes. This research outlines the technology demonstration payload, Resident Space Object Near-space Astrometric Research (RSONAR)-a star tracker-like, wide FOV camera combined with commercial off-the-shelf (COTS) hardware to image RSOs from the stratosphere, overcoming the disadvantages of ground-based observations. The hardware components and software algorithm are described and evaluated. The eligibility of the payload for SSA is proven by the image processing algorithms, which detect the RSOs in the images captured during flight and the survival of the COTS components in the near-space environment. The payload features a low-resolution, wide FOV camera coupled with a Field Programmable Gate Array (FPGA)-based platform that houses the altitude and time-based image capture algorithm. The newly developed payload in a 2U-CubeSat form factor was flown as a space-ready payload on the CSA/CNES stratospheric balloon research platform to carry out algorithm and functionality tests in August 2022.

Patients' experiences of using a mobile application-based rehabilitation programme after total hip or knee arthroplasty: a qualitative descriptive study.

BACKGROUND: An increasing number of patients are discharged from a total hip or knee arthroplasty with a short length of hospital stay. Technologies, such as mobile applications, are used to provide remote support to patients' postoperative rehabilitation. Patients' experiences of receiving mobile application-based rehabilitation after total hip or knee arthroplasty have not been investigated extensively. METHODS: This was a qualitative descriptive study. Twenty-five participants who had completed a mobile application-based rehabilitation programme for total hip or knee arthroplasty were recruited. Semi-structured interviews were conducted via telephone between July 2021 and January 2022 regarding the participants' experiences using the programme. All interviews were audio-recorded and verbatim transcribed. Data were analysed using inductive content analysis. The reporting of this study followed the Consolidated Criteria for Reporting Qualitative Research. RESULTS: Data analysis revealed five categories: (a) improved access to health care, (b) encouraged postoperative recovery, (c) established supportive relationships, (d) facilitated learning, and (e) future directions. CONCLUSION: The theory-underpinned mobile application-based rehabilitation programme demonstrated potential value in supporting patients' rehabilitation after arthroplasty. Nurses can consider using mobile technologies to expand their role in arthroplasty rehabilitation and improve the quality of rehabilitation care.

Bedtime smart device usage and accelerometer-measured sleep outcomes in children and adolescents.

PURPOSE: We analyzed the association between bedtime smart device usage habits and accelerometer-measured sleep outcomes (total sleeping time, sleep efficiency, and wake after sleep onset) in Hong Kong children and adolescents aged 8-14. METHODS: A total of 467 students in Hong Kong participated in this study from 2016 to 2017. They self-reported their bedtime smart device usage habits. The primary caregiver of each participant was also invited to complete a self-administered questionnaire about the family's social-economic status and bedtime smart device usage habits. An ActiGraph GT3X accelerometer was used to assess participants' 7-day sleep outcomes. RESULTS: The mean age of the participants was 10.3 (SD 1.9), and 54% were girls. Among the participants, 27% (n = 139) used a smart device before sleep, and 33% (n = 170) kept the smart device on before sleep. In total, 27% (n = 128) placed the smart device within reach before sleep, 23% (n = 107) would wake up when notifications were received, and 25% (n = 117) immediately checked the device after being awakened by a notification. Multiple regression controlling for age, sex, socio-economic status, and other confounders showed that those who woke up after receiving a notification had a statistically longer sleeping time (19.7 min, 95% CI: 0.3, 39.1, p = 0.046), lower sleep efficiency (- 0.71%, 95% CI - 1.40, - 0.02, p = 0.04), and a longer wake after sleep onset (2.6 min, 95% CI: 0.1, 5.1, p = 0.045) than those who did not. Nonetheless, all primary caregivers' bedtime smart device habits were insignificantly associated with all sleep outcomes of their children. CONCLUSION: Those who woke up after receiving smart device notifications had lower sleep efficiency and longer wake after sleep onset than those who did not, and they compensated for their sleep loss by lengthening their total sleep time.

Metabolic effects of skeletal muscle-specific deletion of beta-arrestin-1 and -2 in mice.

Type 2 diabetes (T2D) has become a major health problem worldwide. Skeletal muscle (SKM) is the key tissue for whole-body glucose disposal and utilization. New drugs aimed at improving insulin sensitivity of SKM would greatly expand available therapeutic options. ß-arrestin-1 and -2 (Barr1 and Barr2, respectively) are two intracellular proteins best known for their ability to mediate the desensitization and internalization of G protein-coupled receptors (GPCRs). Recent studies suggest that Barr1 and Barr2 regulate several important metabolic functions including insulin release and hepatic glucose production. Since SKM expresses many GPCRs, including the metabolically important ß2-adrenergic receptor, the goal of this study was to examine the potential roles of Barr1 and Barr2 in regulating SKM and whole-body glucose metabolism. Using SKM-specific knockout (KO) mouse lines, we showed that the loss of SKM Barr2, but not of SKM Barr1, resulted in mild improvements in glucose tolerance in diet-induced obese mice. SKM-specific Barr1- and Barr2-KO mice did not show any significant differences in exercise performance. However, lack of SKM Barr2 led to increased glycogen breakdown following a treadmill exercise challenge. Interestingly, mice that lacked both Barr1 and Barr2 in SKM showed no significant metabolic phenotypes. Thus, somewhat surprisingly, our data indicate that SKM ß-arrestins play only rather subtle roles (SKM Barr2) in regulating whole-body glucose homeostasis and SKM insulin sensitivity.

RSOnet: An Image-Processing Framework for a Dual-Purpose Star Tracker as an Opportunistic Space Surveillance Sensor.

A catalogue of over 22,000 objects in Earth's orbit is currently maintained, and that number is expected to double within the next decade. Novel data collection regimes are needed to scale our ability to detect, track, classify and characterize resident space objects in a crowded low Earth orbit. This research presents RSOnet, an image-processing framework for space domain awareness using star trackers. Star trackers are cost-effective, flight proven, and require basic image processing to be used as an attitude-determination sensor. RSOnet is designed to augment the capabilities of a star tracker by becoming an opportunistic space-surveillance sensor. Our research demonstrates that star trackers are a feasible source for RSO detections in LEO by demonstrating the performance of RSOnet on real detections from a star-tracker-like imager in space. RSOnet convolutional-neural-network model architecture, graph-based multi-object classifier and characterization results are described in this paper.

Patients' needs regarding rehabilitation services delivered via mobile applications after arthroplasty: A qualitative study.

AIMS AND OBJECTIVES: To obtain an in-depth understanding of the specific needs of patients for rehabilitation services delivered via mobile applications after total hip or knee arthroplasty. BACKGROUND: Due to increased demand for arthroplasty, the provision of face-to-face rehabilitation services for patients is becoming challenging. New approaches using digital technologies are being developed, such as mobile applications to deliver rehabilitation services. However, the perspectives of patients on the delivery of these services via mobile applications after total hip or knee arthroplasty have not been explored extensively. DESIGN: A qualitative descriptive study. METHODS: Twenty patients who had been discharged from the hospital after a total hip or knee arthroplasty were interviewed via telephone about their needs regarding the future use of mobile applications to conduct arthroplasty rehabilitation. Interview records were transcribed verbatim and analysed using inductive content analysis. Reporting of the findings complies with the COREQ checklist for qualitative studies. RESULTS: Four categories emerged from the data collected from the participants: (1) assisting rehabilitation self-management, (2) facilitating peer support, (3) facilitating contact with healthcare professionals and (4) supporting emotional well-being. CONCLUSIONS: The study provided an in-depth understanding of the specific needs of patients for rehabilitation services delivered via mobile applications after total hip or knee arthroplasty. The findings of the study could be used in the development or revision of mobile application rehabilitation programmes to better support the rehabilitation of patients. Future studies are needed to evaluate the effectiveness of such programmes, especially including the self-efficacy of patients as an outcome measure. RELEVANCE TO CLINICAL PRACTICE: From the perspective of patients who have undergone arthroplasty, a mobile application rehabilitation programme should encourage patients in rehabilitation self-management, assist them to contact healthcare professionals and other patients and support their postoperative emotional well-being. The study findings will assist nurses with the preparation and delivery of telerehabilitation programmes after arthroplasty.

Crystal structure of rhodopsin bound to arrestin by femtosecond X-ray laser.

G-protein-coupled receptors (GPCRs) signal primarily through G proteins or arrestins. Arrestin binding to GPCRs blocks G protein interaction and redirects signalling to numerous G-protein-independent pathways. Here we report the crystal structure of a constitutively active form of human rhodopsin bound to a pre-activated form of the mouse visual arrestin, determined by serial femtosecond X-ray laser crystallography. Together with extensive biochemical and mutagenesis data, the structure reveals an overall architecture of the rhodopsin-arrestin assembly in which rhodopsin uses distinct structural elements, including transmembrane helix 7 and helix 8, to recruit arrestin. Correspondingly, arrestin adopts the pre-activated conformation, with a ∼20° rotation between the amino and carboxy domains, which opens up a cleft in arrestin to accommodate a short helix formed by the second intracellular loop of rhodopsin. This structure provides a basis for understanding GPCR-mediated arrestin-biased signalling and demonstrates the power of X-ray lasers for advancing the frontiers of structural biology.

Nurses in advanced roles as a strategy for equitable access to healthcare in the WHO Western Pacific region: a mixed methods study.

BACKGROUND: The Western Pacific region constitutes one-quarter of the world's population and has diverse health needs. While dialogue on and promotion of advanced practice nurses are ongoing, this study investigated the current responsibilities of nurses in advanced roles, future healthcare needs, and the implications of these components for nurses' professional development within the Western Pacific region. METHODS: This study employed three phases, a descriptive survey on the current status of nurses in advanced roles in the Western Pacific region, followed by a Delphi survey, and exploratory interviews. A total of 55 national experts with clinical, academic, and/or government-related backgrounds from 18 countries participated from December 2017 - December 2018. The descriptive survey via email to identify the status of nurses in advanced roles and a working definition was developed. This formed the basis for the Delphi survey, which identified key barriers and challenges for enhancing the development of nurses in advanced roles within the country (round 1) and for the region (rounds 2 and 3). Lastly, semi-structured individual interviews were conducted to identify strategies for establishing nurses in advanced roles to improve equitable access to healthcare. RESULTS: Thirty-seven roles and characteristics were identified and categorized for nurses performing advanced roles. Emergency care, critical care, elderly health, child health, and rural/remote communities were identified as fields with particular need for nurses in advanced roles in the Western Pacific region. Providing effective services, influencing government leadership, and advocating for health system sustainability were deemed necessary to improve equitable healthcare access. We found that nurses in advanced roles are not limited to clinical tasks within the hospital but are poised for active participation in primary healthcare, education/teaching, professional leadership, quality management, and research. CONCLUSIONS: Demand for nurses in advanced roles is high in the Western Pacific region and 15 items were identified across five core strategic areas to enhance development of nurses in advanced roles. Governmental-level recommendations include establishing legislative protection, improving systems for remuneration, strengthening supportive channels, and conducting national needs assessments.

Simulation of RSO Images for Space Situation Awareness (SSA) Using Parallel Processing.

With the rapid increase in resident space objects (RSO), there is a growing demand for their identification and characterization to advance space simulation awareness (SSA) programs. Various AI-based technologies are proposed and demonstrated around the world to effectively and efficiently identify RSOs from ground and space-based observations; however, there remains a challenge in AI training due to the lack of labeled datasets for accurate RSO detection. In this paper, we present an overview of the starfield simulator to generate a realistic representation of images from space-borne imagers. In particular, we focus on low-resolution images such as those taken with a commercial-grade star tracker that contains various RSO in starfield images. The accuracy and computational efficiency of the simulator are compared to the commercial simulator, namely STK-EOIR to demonstrate the performance of the simulator. In comparing over 1000 images from the Fast Auroral Imager (FAI) onboard CASSIOPE satellite, the current simulator generates both stars and RSOs with approximately the same accuracy (compared to the real images) as STK-EOIR and, an order of magnitude faster in computational speed by leveraging parallel processing methodologies.

Improved Accuracy of a Single-Slit Digital Sun Sensor Design for CubeSat Application Using Sub-Pixel Interpolation.

In recent years, we have seen significant improvements in the digital sun sensor (DSS) design enabled by advanced micro-systems fabrication and optical sensing technologies. In this paper, we propose a simple single-slit DSS concept with improved accuracy using sub-pixel interpolation. In considering the DSS design, we focused on several characteristics of the sun sensor, including field-of-view, sensor accuracy, complexity, and computational requirements. First, the optimal mask design was determined based on the simple geometry of the slit size, mask height and pixel width. Then, a two-step pixel read-out algorithm was implemented for sub-pixel level interpolation to determine the illumination ratio using 1-, 2-, 4- and 8-bit readouts. Lastly, the improved DSS was integrated with typical CubeSat, commercial-grade attitude sensors suite and a simple TRIAD method to determine the attitude of a CubeSat in LEO. Compared to standard 1-bit read-out mode (0.32 deg RMSE), 8-bit DSS achieves better than 0.01 deg RMSE. In a CubeSat scenario, improvements in attitude knowledge and control accuracy are marginal when using TRIAD, due to the significantly lower accuracy in other CubeSat-scale sensors (magnetometer, for example).

Effects of a group mindfulness-based cognitive programme on smartphone addictive symptoms and resilience among adolescents: study protocol of a cluster-randomized controlled trial.

BACKGROUND: Smartphone addiction in adolescent is a significant global health issue since the last decade. Evidence has shown that the uncontrolled use of smartphone would lead to undesirable impact on their growth and development. However, evidence-based interventions to manage adolescents' smartphone addictive behaviors is lacking. The proposed study aims to examine the effect of a group mindfulness-based cognitive programme(MBCP) on resilience, smartphone behavior and addictive symptoms in young adolescents. METHODS: It is an open-label, parallel-group, cluster-randomized controlled trial with repeated measurement analysis. Four primary schools in Hong Kong will be recruited and randomly allocated in a ratio of 1:1 to the intervention/control group. A convenience sample of 240 class level 5 primary school students, 60 from each school, will be recruited. Participants in the intervention group will receive a 12-week MBCP which comprises 90-minute supervised practice at school and daily home practice. Resilience will be measured by Connor-Davidson Resilience Scale - 25 (Chinese version); smartphone behavior will be represented by time spent/day using the smartphone and types of functions used; addictive symptoms will be measured by Smartphone Addiction Scale-Short Version (Chinese Version). Baseline assessment(T0) will be conducted before the intervention starts. Post-tests will be conducted in weeks 4, 8, 12 of the intervention, and 3 months follow-up. Intention-to-Treat analysis will be applied to the variables. Generalized Estimating Equation model will be used to compare differences in resilience scores, smartphone behavior and addiction scores between and within groups, adjusted for socio-demographic factors. P < 0.05 with two-tailed test will be regarded as significance. DISCUSSION: It is expected that adolescents will demonstrate better resilience and lesser smartphone addictive symptoms after joining the MBCP. The study will be the first provided empirical evidence to support the promising application of MBCP to manage smartphone use among adolescents. It introduces community stakeholders including community nurses a non-invasive and simple-to-administer intervention to tackle problematic smartphone use among adolescent clients. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2000033273, Registered on 26 May 2020.