On Higher-Order Statistics of the Channel Model for UAV-to-Ground Communications

Proceedings of: 2021 IEEE 93rd Vehicular Technology (VTC2021-Spring), 25-28 april, 2021, Helsinki, Finland.Unmanned-aerial-vehicles (UAVs) based communications are envisioned to play an important role in 5G and beyond 5G (B5G) systems. UAV-to-ground communications in urban cities are often characterized by highly dynamic propagation environments that can be described by composite fading channels. Most of the UAV-to-ground systems are based on first order (FO) performance evaluation, however the models based on FO statistics are insufficient for characterization of time variant fading channels. We provide comprehensive mathematical framework for the second order (SO) statistics over double-scattered, double-shadowed (DS-DS) fading channels, modeled as the product of double Nakagami-m (DN) and double inverse Gamma (DIG) random processes (RPs). In particular, we obtained exact mathematical expressions for average fade duration (AFD) and level crossing rate (LCR) of the proposed UAV-to-ground channel model. Moreover, the exact, integral form SO statistical expressions are approximated by Laplace Integration (LI) and exponential LI in order to provide closed form, easily computing mathematical expressions. Numerical results show that approximate and exact results are fitting well, especially for higher output threshold values. The impact of DS-DS fading severities on the SO statistics are well investigated. Furthermore, the proposed method is extended to analyze SO performances for the selection scenario of UAV with the highest signal level from among N-UAVs links.C. Stefanovic would like to acknowledge CONEX-Plus. The CONEX-Plus is funded by UC3M, the European Commission through the Marie Sklodowska Curie COFUND Action (H2020-MSCA-COFUND-2017- GA 801538)

On the ASER performance of UAV-based communication systems for QAM schemes

In this letter, we derive an average symbol error rate (ASER) expression of rectangular quadrature amplitude modulation (RQAM) scheme for unmanned aerial vehicle-enabled communication systems operating over double-shadowing and double-scattering composite fading channel. A moment generating function for the receiver output signal-to-noise ratio is obtained to analyze the ASER expression of non-coherent modulation schemes. An asymptotic expression of ASER for RQAM scheme is also derived to examine diversity order of the considered system. Further, the impact of composite fading parameters and path loss on ASER performance is highlighted. Finally, we validate all the theoretical results through Monte Carlo simulations

Clinical profile of patients with prosthetic heart valve thrombosis undergoing fibrinolytic therapy and NYHA class as a predictor of outcome

Background: Prosthetic heart valve thrombosis (PHVT) is a potentially fatal complication of heart valve replacement with mechanical prostheses mainly due to thrombosis.Aim: The study aimed to evaluate the clinical profile of the patients presenting with PHVT undergoing fibrinolytic therapy and analyzing patients with respect to New York Heart Association (NYHA) functional class on presentation and its association with outcome of fibrinolytic therapy.Settings & design: This was prospective, observational study conducted from June, 2016 to April, 2017. Total 133 patients with prosthetic heart valve thrombosis were included. Materials and methods: Routine blood investigations included complete hemogram, liver and renal function tests. Prothrombin time with INR was done on admission. The diagnosis of PHVT was assessed by fluoroscopy and/or echocardiography (transthoracic/transesophageal). Follow-up at 6 months was scheduled for all patients.Statistical analysis: Parametric values between two groups were performed using the independent sample t-test or chi-square test, as appropriate. Univariate and multivariate logistic regression was used to find out factors associated with outcome.Results: All patients received fibrinolytic therapy in which 108 (81.2%) were treated with streptokinase and 25 (18.8%) were treated with urokinase. On presentation, 48.9% patients were in NYHA class III, 41.4% in NYHA class IV and 9.77% in NYHA class II. Fibrinolytic therapy was successful in 105 patients (78.9%) and it failed in 28 patients (21.1%). Mortality in NYHA class II was 0%, NYHA class III was 4.6% and in NYHA class IV was 23.6%. During 6 months follow up prosthetic heart valve thrombosis recurred in 12 (11.43%) patients.Conclusion: From our single centre experience, fibrinolytic therapy is fairly effective first line therapy for prosthetic heart valve thrombosis and NYHA functional class on presentation can predict the outcome of fibrinolytic therapy

A STUDY OF RECOVERY FROM GENERAL ANAESTHESIA AFTER PREOPERATIVE ADMINISTRATION OF ANTIMICROBIAL

ABSTRACT Antimicrobials are used prophylactily in any major surgery to cover perioperative wound infection and other infectious complication ,that may have interaction with muscle relaxant used for general anesthesia and the aim of our study is drug interaction and behavioural response of newly introduced antibiotics used with rocuronium. Gentamicin shortened onset and duration of block after intubating dose of rocuronium and also prolonged duration of extubation after last dose of rocuronium where as meropenem and ceftriaxone did not alter onset, duration and recovery characterstics of rocuronium. . From our study we can conclude that meropenem and ceftriaxone but not gentamicin, can be used safely during general anesthesia. The near ideal muscle relaxant must span the range of short, intermediate and long acting duration (as required by surgical procedure),have rapid onset, be highly metabolized, have no cumulative or cardiovascular effect, to be independent of kidney for elimination, and be easily antagonized. The most commonly used clinical agentsatracurium, doxacurium, vecuronium, pancuronium and pipecuronium-demonstrate some, but not all, of these properties. KEYWORDS : Rocuronium bromide is a relatively new nondepolarizing muscle relaxant. It is the first of these agents to have an onset time possibly as brief as that of suxamethonium without adverse side effect. Rocuronium bromide is mono-quaternary, aminosteroidal, nondepolarizing neuromuscular blocking agent with a rapid onset of actio

Clinical outcome, viral response and safety profile of chloroquine in COVID-19 patients — initial experience

Introduction: Chloroquine and its analogues are currently being investigated for the treatment and post exposure prophylaxis of COVID-19 due to its antiviral activity and immunomodulatory activity.Material and methods: Confirmed symptomatic cases of COVID-19 were included in the study. Patients were supposed to receive chloroquine (CQ) 500 mg twice daily for 7 days. Due to a change in institutional protocol, initial patients received chloroquine and subsequent patients who did not receive chloroquine served as negative controls. Clinical effectiveness was determined in terms of timing of symptom resolution and conversion rate of reverse transcriptase polymerase chain reaction (RT-PCR) on day 14 and day 15 of admission.Results: Twelve COVID-19 patients formed the treatment arm and 17 patients were included in the control arm. The duration of symptoms among the CQ treated group (6.3 ± 2.7 days) was significantly (p-value = 0.009) lower than that of the control group (8.9 ± 2.2 days). There was no significant difference in the rate of RT-PCR negativity in both groups. 2 patients out of 12 developed diarrhea in the CQ therapy arm.  Conclusion: The duration of symptoms among the treated group (with chloroquine) was significantly lower than that of the control group. RT-PCR conversion was not significantly different between the 2 groups

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990–2017: A systematic analysis for the Global Burden of Disease Study 2017

Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data. Methods: We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting. Findings: Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs 1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]). Interpretation: Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury

Nations within a nation: variations in epidemiological transition across the states of India, 1990–2016 in the Global Burden of Disease Study

18% of the world's population lives in India, and many states of India have populations similar to those of large countries. Action to effectively improve population health in India requires availability of reliable and comprehensive state-level estimates of disease burden and risk factors over time. Such comprehensive estimates have not been available so far for all major diseases and risk factors. Thus, we aimed to estimate the disease burden and risk factors in every state of India as part of the Global Burden of Disease (GBD) Study 2016

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo