A novel double-sided pulse interval modulation (DS-PIM) aided SIM-OFDM for 6G light fidelity (LiFi) networks

Subcarrier Index Modulation is an OFDM variant that provides superior power and bandwidth efficiency. In this paper, we present a novel, double-sided pulse interval modulation (DS-PIM)-based SIM OFDM technique. The proposed technique exploits the variable symbol size of DPIM to provide a variable sub-block size and enable dynamic assignment of subcarriers rather than the fixed size of conventional SIM OFDM. In comparison with conventional Subcarrier Index-Modulated OFDM (SIM-OFDM), the proposed approach shows a 12.5% reduction in bandwidth usage for a 2-bit index word. On average, 3.5 subcarriers are employed by the proposed technique per sub-block, in comparison with 4 subcarriers for the conventional technique. The proposed technique provides a superior spectral efficiency compared with conventional SIM-OFDM, even for higher-order modulation

Study of environmental enteropathy and malnutrition (SEEM) in Pakistan: protocols for biopsy based biomarker discovery and validation

Background: Environmental Enteropathy (EE), characterized by alterations in intestinal structure, function, and immune activation, is believed to be an important contributor to childhood undernutrition and its associated morbidities, including stunting. Half of all global deaths in children \u3c 5 years are attributable to under-nutrition, making the study of EE an area of critical priority. Methods: Community based intervention study, divided into two sub-studies, 1) Longitudinal analyses and 2) Biopsy studies for identification of EE features via omics analyses. Birth cohorts in Matiari, Pakistan established: moderately or severely malnourished (weight for height Z score (WHZ) \u3c − 2) children, and well-nourished (WHZ \u3e 0) children. Blood, urine, and fecal samples, for evaluation of potential biomarkers, will be collected at various time points from all participants (longitudinal analyses). Participants will receive appropriate educational and nutritional interventions; non-responders will undergo further evaluation to determine eligibility for further workup, including upper gastrointestinal endoscopy. Histopathological changes in duodenal biopsies will be compared with duodenal biopsies obtained from USA controls who have celiac disease, Crohn’s disease, or who were found to have normal histopathology. RNA-Seq will be employed to characterize mucosal gene expression across groups. Duodenal biopsies, luminal aspirates from the duodenum, and fecal samples will be analyzed to define microbial community composition (omic analyses). The relationship between histopathology, mucosal gene expression, and community configuration will be assessed using a variety of bioinformatic tools to gain better understanding of disease pathogenesis and to identify mechanism-based biomarkers. Ethical review committees at all collaborating institutions have approved this study. All results will be made available to the scientific community. Discussion: Operational and ethical constraints for safely obtaining intestinal biopsies from children in resource-poor settings have led to a paucity of human tissue-based investigations to understand and reverse EE in vulnerable populations. Furthermore, EE biomarkers have rarely been correlated with gold standard histopathological confirmation. The Study of Environmental Enteropathy and Malnutrition (SEEM) is designed to better understand the pathophysiology, predictors, biomarkers, and potential management strategies of EE to inform strategies to eradicate this debilitating pathology and accelerate progress towards the 2030 Sustainable Development Goals. Trial registration: Retrospectively registered; clinicaltrials.gov ID NCT03588013

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

ELAM : a model for acceptance and use of e-learning by teachers and students

Use of technology to facilitate learning is accepted to be of value across educational institutions. Government of India has taken cognizance of the institutional support required for resources in e-learning and formulated the national mission on education through ICT. However, the focus is still largely on getting the infrastructure and creating the e-learning content. It is necessary to consider the individual factors that play an important role in the adoption of e-learning. For example, attitude of students and teachers towards e-learning may affect their acceptance of the technology in the teaching-learning process. While there have been studies to understand the factors of the instructors (e.g release time for staff to engage in e-learning) and students (e.g. learning style) in acceptance of e-learning separately, a comprehensive view that considers both students and teachers in the same model is lacking (Jung, et. al., 2008; Nanayakkara 2007). To addresses this research gap, this paper considers the attitudes of students and the teachers that determine intention and actual use of the e-learning technology simultaneously in the model of e-learning. We present a conceptual framework for understanding acceptance of e-learning technology. Our model, ELAM, is based on the Unified Theory of Acceptance and Use of Technology (Venkatesh, et. al. 2003). ELAM (e-learning acceptance model) identifies the key factors in acceptance of e-learning as measured by behavioural intention to use the technology and actual usage. The four determinants of e-learning acceptance are --- (i) performance expectancy, (ii) effort expectancy, (iii) social influence and (iv) facilitating conditions. Performance expectancy is based on beliefs about perceived usefulness, interactivity and flexibility. Effort expectancy is based on beliefs about ease of learning, perceived ease of use and self-efficacy. Social influence is based on subjective norm and image. In developing countries, wherein educational institutions depend on governmental support to get the infrastructure and determine policies, institutional support plays a crucial role in the acceptance of e-learning. Hence, the model includes facilitating conditions as one of the determinants of e-learning acceptance. The following factors are included in this variable --- reliable infrastructure, institutional policies, training and support. As e-learning is associated with individualization of the teaching-learning process, the learning style of the student and teaching style of the teacher is an important factor affecting the adoption process. These factors are considered as mediators affecting the relation between performance expectancy beliefs and behavioural intention to use e-learning. The main contribution of the paper is that it presents a framework to understand e-learning acceptance as governed by the teacher, student and institutional factors

A Novel Double-Sided Pulse Interval Modulation (DS-PIM) Aided SIM-OFDM for 6G Light Fidelity (LiFi) Networks

Subcarrier Index Modulation is an OFDM variant that provides superior power and bandwidth efficiency. In this paper, we present a novel, double-sided pulse interval modulation (DS-PIM)-based SIM OFDM technique. The proposed technique exploits the variable symbol size of DPIM to provide a variable sub-block size and enable dynamic assignment of subcarriers rather than the fixed size of conventional SIM OFDM. In comparison with conventional Subcarrier Index-Modulated OFDM (SIM-OFDM), the proposed approach shows a 12.5% reduction in bandwidth usage for a 2-bit index word. On average, 3.5 subcarriers are employed by the proposed technique per sub-block, in comparison with 4 subcarriers for the conventional technique. The proposed technique provides a superior spectral efficiency compared with conventional SIM-OFDM, even for higher-order modulation

A Novel Double-Sided Pulse Interval Modulation (DS-PIM) Aided SIM-OFDM for 6G Light Fidelity (LiFi) Networks

Subcarrier Index Modulation is an OFDM variant that provides superior power and bandwidth efficiency. In this paper, we present a novel, double-sided pulse interval modulation (DS-PIM)-based SIM OFDM technique. The proposed technique exploits the variable symbol size of DPIM to provide a variable sub-block size and enable dynamic assignment of subcarriers rather than the fixed size of conventional SIM OFDM. In comparison with conventional Subcarrier Index-Modulated OFDM (SIM-OFDM), the proposed approach shows a 12.5% reduction in bandwidth usage for a 2-bit index word. On average, 3.5 subcarriers are employed by the proposed technique per sub-block, in comparison with 4 subcarriers for the conventional technique. The proposed technique provides a superior spectral efficiency compared with conventional SIM-OFDM, even for higher-order modulation

MULTIOBJECTIVE PSSs DESIGN FOR DAMPING INTRA-AREA OSCILLATIONS IN MULTI-MACHINES POWER SYSTEM USING HIERARCHICAL MICRO GA

In recent years, the occurrence of Low Frequency Oscillations (LFOs) has increased due lo the growth in size and complexity of power systems. This has strong impact on overall system and can deteriorate power system angular stability. The classical and cost effective way of preventing low-frequency oscillations in power system is to use power system stabilizers (PSSs). These controllers have been traditionally designed using classical theory such as eigenvalue/eigenvector analyses, root locus, etc., and are made of lead-lag networks. However, because the parameters of the controllers are fixed they cannot provide adequate damping over a wide range of operating conditions. The objective of this paper is to develop cost-effective control strategy that maintain the lead-lag structure of existing PSSs while optimizing the robust performance of the controller to cope with various uncertainties in the system and varying operating conditions.In this paper a method for selecting and tuning multiple power system damping controllers simultaneously by genetic algorithms (GA s) has presented. The performance of the control system is considered for different operating conditions to ensure robustness of the controllers. Robust multi objective design of the PSSs is achieved that ensures system stability by shifting the poles to the desired place in the left half s-plane

Comparison of Vicryl, Dexon and Intestinal Stapler for the Closure of Colon in Dogs

Eighteen healthy mongrel dogs of sexes, varying ages (16.50 ± 0.22 months) and weights (19.83 ± 0.16 kg) were used in this study. The experiment was conducted in the | department of Surgery and Obstetrics, Faculty of Animal Husbandry and Veterinary Sciences, Sindh Agriculture University, Tandojam.A total of 18 dogs (male and female) were randomly divided into three groups placing 6 animals in each i.e., group-A (Vicryl 3/0 suture material), B (Dexon 3/0 suture material) and C (stapler). Physically healthy animals were used in this study in order to achieve the required results. Xylazine (9.91 ± 0.08 mg/dog) and thiopental Sodium (198.33 ± 1.05 mg/dog) was administered intramuscularly in all groups. The anaesthetized animals were placed on the dorsal recumbancy on surgical table in order to perform surgical procedure. The caudal ventral midline incision of 5 cm was made in all dogs to exteriorized the colon. One incision of 5 cm was given on colon and bleeding was controlled by artery forceps. Colon incision was closed with Vicryl (3/0) in group-A, Dixon (3/0) in group-B and intestinal stapling materials in dogs of group-C. The peritoneum in each dog was sutured with chromic catgut by simple interrupted suture technique, the linea alba was sutured with chromic catgut by simple continuous suture technique, sub-cutaneous layer was apposed with sub-cuticular suture technique using 3/0 chromic catgut. Skin was closed with simple interrupted suture pattern using silk 2/0 suture material in dogs.The total duration of anesthesia required was 328.33 ± 1.17, 330.00 ± 1.39 and 313.83 ± 2.52 minutes for closure of colon closed with Vicryl, Dexon and Stapling material respectively. The mean number of total stitches for colon closure with Vicryl, Dexon and stapling material was 15 ±0.57. 17.00 ± 0.36 and 6.66 ± 0.21 respectively. Though the partial development of mucosal folds can be seen on day 10 of post-surgery whereas fully development except lamina epithelia on day 20. It is concluded that Vicryl suture material showed the superiority in terms of better apposition of the sutured tissues and better healing and lesser complications like minimal adhesions between sutured site and other structures applied with double layer appositional suture technique for the closure of colon in dogs. This study also reveals that all suture materials were not completely free from complications but staple technique showed quicker application and lesser number of staples was required as compare to Vicryl and Dexon suture stitches and duration.

Comparison of Vicryl, Dexon and Intestinal Stapler for the Closure of Colon in Dogs

Eighteen healthy mongrel dogs of sexes, varying ages (16.50 ± 0.22 months) and weights (19.83 ± 0.16 kg) were used in this study. The experiment was conducted in the | department of Surgery and Obstetrics, Faculty of Animal Husbandry and Veterinary Sciences, Sindh Agriculture University, Tandojam.A total of 18 dogs (male and female) were randomly divided into three groups placing 6 animals in each i.e., group-A (Vicryl 3/0 suture material), B (Dexon 3/0 suture material) and C (stapler). Physically healthy animals were used in this study in order to achieve the required results. Xylazine (9.91 ± 0.08 mg/dog) and thiopental Sodium (198.33 ± 1.05 mg/dog) was administered intramuscularly in all groups. The anaesthetized animals were placed on the dorsal recumbancy on surgical table in order to perform surgical procedure. The caudal ventral midline incision of 5 cm was made in all dogs to exteriorized the colon. One incision of 5 cm was given on colon and bleeding was controlled by artery forceps. Colon incision was closed with Vicryl (3/0) in group-A, Dixon (3/0) in group-B and intestinal stapling materials in dogs of group-C. The peritoneum in each dog was sutured with chromic catgut by simple interrupted suture technique, the linea alba was sutured with chromic catgut by simple continuous suture technique, sub-cutaneous layer was apposed with sub-cuticular suture technique using 3/0 chromic catgut. Skin was closed with simple interrupted suture pattern using silk 2/0 suture material in dogs.The total duration of anesthesia required was 328.33 ± 1.17, 330.00 ± 1.39 and 313.83 ± 2.52 minutes for closure of colon closed with Vicryl, Dexon and Stapling material respectively. The mean number of total stitches for colon closure with Vicryl, Dexon and stapling material was 15 ±0.57. 17.00 ± 0.36 and 6.66 ± 0.21 respectively. Though the partial development of mucosal folds can be seen on day 10 of post-surgery whereas fully development except lamina epithelia on day 20. It is concluded that Vicryl suture material showed the superiority in terms of better apposition of the sutured tissues and better healing and lesser complications like minimal adhesions between sutured site and other structures applied with double layer appositional suture technique for the closure of colon in dogs. This study also reveals that all suture materials were not completely free from complications but staple technique showed quicker application and lesser number of staples was required as compare to Vicryl and Dexon suture stitches and duration.