An Improved Fuzzy Logic Controller Design for PV Inverters Utilizing Differential Search Optimization

This paper presents an adaptive fuzzy logic controller (FLC) design technique for photovoltaic (PV) inverters using differential search algorithm (DSA). This technique avoids the exhaustive traditional trial and error procedure in obtaining membership functions (MFs) used in conventional FLCs. This technique is implemented during the inverter design phase by generating adaptive MFs based on the evaluation results of the objective function formulated by the DSA. In this work, the mean square error (MSE) of the inverter output voltage is used as an objective function. The DSA optimizes the MFs such that the inverter provides the lowest MSE for output voltage and improves the performance of the PV inverter output in terms of amplitude and frequency. The design procedure and accuracy of the optimum FLC are illustrated and investigated using simulations conducted for a 3 kW three-phase inverter in a MATLAB/Simulink environment. Results show that the proposed controller can successfully obtain the desired output when different linear and nonlinear loads are connected to the system. Furthermore, the inverter has reasonably low steady state error and fast response to reference variation

The relation of Echocardiographic findings to pulmonary Function tests in patients with Chronic obstructive Pulmonary Disease

Background: Chronic obstructive pulmonary disease (COPD) is a common disease and it accounts for over 10% of all hospital medical admission. Cigarette smoking is the most important risk factor. Pulmonary arterial hypertension (PHT) is a common complication of COPD and the increase in pulmonary artery pressure is often mild to moderate. The presence of pulmonary arterial pressure and its severity is readily and reliably determined by transthoracic echocardiography in majority of COPD patients. Patients and Methods: This study included 55 patients with mean age 65.6 ±8.2 years .The mean duration of symptoms was 18 ±10 months. 32 patients (58%) were current smoker, 18 patients (33%) were exsmoker and 5 patients (9%) were non smoker. The mean intensity of smoking for smoker was 49.5 ± 22.2 pack- years. For all patients, history, clinical examination, ECG, CXR, and routine blood tests were done. For all patients pulmonary function tests were done and patients were classified according to GOLD criteria into 4 stages. Echocardiography was done for all patients; ventricular and atrial dimensions were taken, and using Doppler technique to detect tricuspid and pulmonary regurgitation, estimation of pulmonary artery systolic and/or diastolic pressure using special formulas was undertaken. Results: Tricuspid regurgitation (TR) jet was found in 70.9% of patients with COPD. Increased pulmonary artery systolic pressure was found in 51% of patients with TR (36% of total patients) and increased pulmonary vascular resistance was found in 48.7% of patients with TR (34.5% of total patients). There were significant associations between echo findings of increasing RV size, TR, increased pulmonary arterial pressure and pulmonary vascular resistance with decrease in FEV1, FEV1/VC and oxygen saturation. There was no significant association with decrease in vital capacity. Conclusions: There is a high prevalence of pulmonary arterial hypertension with increasing severity of chronic obstructive pulmonary disease

Asthma and COPD as co-morbidities in patients hospitalised with Covid-19 disease: a global systematic review and meta-analysis

Background: Factors predisposing to increased mortality with COVID-19 infection have been identified as male sex, hypertension, obesity, and increasing age. Early studies looking at airway diseases gave some contradictory results. The purpose of our study was to determine global variation in studies in patients hospitalized with COVID-19 in the prevalence of COPD and asthma; and to determine whether the presence of asthma or COPD affected mortality in the same hospital population. Methods: A systematic review and meta-analysis of the published literature of COPD and asthma as co-morbidities in patients hospitalized with COVID-19 was performed, looking firstly at the prevalence of these diseases in patients hospitalized with COVID-19, and secondly at the relative risk of death from any cause for patients with asthma or COPD. Results: Prevalence of both airway diseases varied markedly by region, making meaningful pooled global estimates of prevalence invalid and not of clinical utility. For individual studies, the interquartile range for asthma prevalence was 4.21 to 12.39%, and for COPD, 3.82 to 11.85%. The relative risk of death with COPD for patients hospitalized with COVID-19 was 1.863 (95% CI 1.640–2.115), while the risk with asthma was 0.918 (95% CI 0.767 to 1.098) with no evidence of increased mortality. Conclusions: For asthma and COPD, prevalence in patients hospitalized with COVID-19 varies markedly by region. We found no evidence that asthma predisposed to increased mortality in COVID-19 disease. For COPD, there was clear evidence of an association with increased mortality. Trial registration: The trial was registered with PROSPERO: registration number CRD42021289886

Effective Lagrangian Approach to Weak Radiative Decays of Heavy Hadrons

Motivated by the observation of the decay $\bar{B}\to \bar{K}^*\gamma$ by CLEO, we have systematically analyzed the two-body weak radiative decays of bottom and charmed hadrons. There exist two types of weak radiative decays: One proceeds through the short-distance $b\to s\gamma$ transition and the other occurs through $W$-exchange accompanied by a photon emission. Effective Lagrangians are derived for the $W$-exchange bremsstrahlung processes at the quark level and then applied to various weak electromagnetic decays of heavy hadrons. Predictions for the branching ratios of $\bar{B}^0\to D^{*0} \gamma,~\Lambda_b^0\to\Sigma_c^0\gamma,~\Xi_b^0\to \Xi_c^0\gamma$ and \Xi_b^0\to\xip_c^0\gamma are given. In particular, we found ${\cal B}(\bar{B}^0 \to D^{*0}\gamma)\approx 0.9\times 10^{-6}$. Order of magnitude estimates for the weak radiative decays of charmed hadrons: $~D^0\to \bar{K}^{*0}\gamma,~\Lambda_c^+\to\Sigma^+\gamma$ and $\Xi_c^0\to\Xi^0\gamma$ are also presented. Within this approach, the decay asymmetry for antitriplet to antitriplet heavy baryon weak radiative transitions is uniquely predicted by heavy quark symmetry. The electromagnetic penguin contribution to $\Lambda_b^0\to\Lambda\gamma$ is estimated by two different methods and its branching ratio is found to be of order $1\times 10^{-5}$. We conclude that weak radiative decays of bottom hadrons are dominated by the short-distance $b\to s\gamma$ mechanism.Comment: 28 pages + 3 figures (not included), CLNS 94/1278, IP-ASTP-04-94. [Main changes in this revised version: (i) Sect 2 and subsection 4.1 are revised, (ii) A MIT bag method for calculating the decay rate of $Lambda_b \to\Lambda+gamma$ is presented, (iii) All predictions are updated using the newly available 1994 Particle Data Group, and (iv) Appendix and subsections 3.3 and 4.4 are deleted.

Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) and the direct CP asymmetry in B0 -> K*0 gamma

The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma and Bs0 phi gamma has been measured using an integrated luminosity of 1.0 fb-1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of sqrt(s)=7 TeV. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) = 1.23 +/- 0.06(stat.) +/- 0.04(syst.) +/- 0.10(fs/fd), where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for BR(B0 -> K*0 gamma), the branching fraction BR(Bs0 -> phi gamma) is measured to be (3.5 +/- 0.4) x 10^{-5}. The direct CP asymmetry in B0 -> K*0 gamma decays has also been measured with the same data and found to be A(CP)(B0 -> K*0 gamma) = (0.8 +/- 1.7(stat.) +/- 0.9(syst.))%. Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations.Comment: 21 pages, 3 figues, 4 table

Leptonic and Semileptonic Decays of Charm and Bottom Hadrons

We review the experimental measurements and theoretical descriptions of leptonic and semileptonic decays of particles containing a single heavy quark, either charm or bottom. Measurements of bottom semileptonic decays are used to determine the magnitudes of two fundamental parameters of the standard model, the Cabibbo-Kobayashi-Maskawa matrix elements $V_{cb}$ and $V_{ub}$. These parameters are connected with the physics of quark flavor and mass, and they have important implications for the breakdown of CP symmetry. To extract precise values of $|V_{cb}|$ and $|V_{ub}|$ from measurements, however, requires a good understanding of the decay dynamics. Measurements of both charm and bottom decay distributions provide information on the interactions governing these processes. The underlying weak transition in each case is relatively simple, but the strong interactions that bind the quarks into hadrons introduce complications. We also discuss new theoretical approaches, especially heavy-quark effective theory and lattice QCD, which are providing insights and predictions now being tested by experiment. An international effort at many laboratories will rapidly advance knowledge of this physics during the next decade.Comment: This review article will be published in Reviews of Modern Physics in the fall, 1995. This file contains only the abstract and the table of contents. The full 168-page document including 47 figures is available at http://charm.physics.ucsb.edu/papers/slrevtex.p

Exposure to secondary traumatic stress and its related factors among emergency nurses in Saudi Arabia: a mixed method study

Background: Emergency department (ED) nurses are exposed to the risk of secondary traumatic stress (STS), which poses a threat not only to nurses’ health and psychological well-being but also adversely affects the execution of their professional duties. The quality and outcome of their nursing services are negatively affected by STS. Purpose: The purpose of this study is to comprehensively investigate the prevalence and intensity of Secondary Traumatic Stress (STS) among Emergency Department (ED) nurses. It aims to identify and analyze the socio-demographic, occupational, and psychological factors that influence the severity and variation of STS experienced by these nurses. Methods: The study utilized a sequential explanatory mixed methods approach, including two phases. Phase 1 employed a cross-sectional study design, utilizing a convenience sample of 181 nurses to explore the levels of STS and the factors associated with it. Following this, Phase 2 was structured as a qualitative descriptive study, which involved conducting semi-structured interviews with a purposefully selected group of ten ED nurses. Data collection took place at three major hospitals in Saudi Arabia during the period from January to June 2022. Results: A total of 181 participants were included in the study. The mean STSS score reported by the nurses was 51 (SD = 13.23) out of the maximum possible score of 85, indicating severe STS among ED nurses. Factors associated with an increase in the levels of STS among ED nurses included being female, older in age, married, possessing higher education and experience, having a positive relationship with colleagues, receiving organisational support, and dealing with a higher number of trauma cases. Several themes emerged from the qualitative interviews including: ED Characteristics: Dual Impact on STS, Emotional Resonance and Vulnerability, Personal Life Stressors, The Ability to Cope, and Social Support. Conclusion and implications for practice: Future strategies and interventions targeting STS should be prioritized to effectively manage its impact on ED nurses. It is crucial to develop targeted interventions that address the specific factors contributing to STS, as identified in this study. Additionally, these findings aim to enhance awareness among nursing administrators, managers, and supervisors about the critical factors associated with STS. This awareness is essential for accurately assessing and developing interventions that mitigate STS among nursing staff

Global Perspectives on Task Shifting and Task Sharing in Neurosurgery.

BACKGROUND: Neurosurgical task shifting and task sharing (TS/S), delegating clinical care to non-neurosurgeons, is ongoing in many hospital systems in which neurosurgeons are scarce. Although TS/S can increase access to treatment, it remains highly controversial. This survey investigated perceptions of neurosurgical TS/S to elucidate whether it is a permissible temporary solution to the global workforce deficit. METHODS: The survey was distributed to a convenience sample of individuals providing neurosurgical care. A digital survey link was distributed through electronic mailing lists of continental neurosurgical societies and various collectives, conference announcements, and social media platforms (July 2018-January 2019). Data were analyzed by descriptive statistics and univariate regression of Likert Scale scores. RESULTS: Survey respondents represented 105 of 194 World Health Organization member countries (54.1%; 391 respondents, 162 from high-income countries and 229 from low- and middle-income countries [LMICs]). The most agreed on statement was that task sharing is preferred to task shifting. There was broad consensus that both task shifting and task sharing should require competency-based evaluation, standardized training endorsed by governing organizations, and maintenance of certification. When perspectives were stratified by income class, LMICs were significantly more likely to agree that task shifting is professionally disruptive to traditional training, task sharing should be a priority where human resources are scarce, and to call for additional TS/S regulation, such as certification and formal consultation with a neurosurgeon (in person or electronic/telemedicine). CONCLUSIONS: Both LMIC and high-income countries agreed that task sharing should be prioritized over task shifting and that additional recommendations and regulations could enhance care. These data invite future discussions on policy and training programs