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In recent years, the global expansion of solar photovoltaic power plants has seen rapid acceleration fueled by technological advancements, substantial cost reductions, and favorable regulatory reforms. Although pivotal to the transition towards sustainable energy sources, the integration of a large number of photovoltaic plants presents unique challenges for the system operator in ensuring grid stability and security. Therefore, it has become increasingly important for these plants to provide adequate grid support services and maintain voltage and frequency stability, similar to conventional generators. In this context, this paper critically analyses the diverse strategies and advanced trends for acquiring grid support services from solar photovoltaic power plants. The relevant procedures are garnered from the literature, which dates back to the earliest reported methods. The review encompasses the analysis of different applications related to active power control for frequency regulation, reactive power control for voltage regulation, and black-start support for system restoration. The paper also examines the existing challenges and delves into the opportunities to transform the interaction of photovoltaic power plants with electricity grids. As solar photovoltaic penetration increases, the role of these grid support services becomes ever more critical, requiring innovative solutions, conducive regulatory frameworks, and a thriving market structure to support the continuously evolving energy landscape. [Display omitted] • Analysis of advanced grid support strategies for integration of solar PV systems. • Critical review of active and reactive power controls in PV systems. • Scrutiny of challenges and innovations in PV-based frequency and voltage regulation. • Discussion on potential black start ancillary services from solar PV systems. • Prospective solutions for enhanced PV-grid interaction amid growing solar adoption. [ABSTRACT FROM AUTHOR]

Highlights • Variable renewable energy integration diminishes synchronous inertia of power systems, resulting in vulnerable frequency instability. • Alternative options of fast frequency resources are required for secure and stable grid operation under high penetration of renewables. • This paper provides a critical review of potential sources of fast frequency reserves, and way forward to maintain secure and stable grid operation. Abstract The last few decades have seen renewable energy source (RES) integration growing at a rapid pace and this trend is likely to continue. The displacement of conventional synchronous plant, particularly at higher RES shares, is resulting in a 'lighter' system with low system inertia and reduced governor droop stiffness, leading to increased vulnerability to fast frequency stability. This paper presents a review of literature from the research and industry communities on possible sources of non-synchronous fast frequency reserve, considered as a potential solution to address diminishing synchronous reserve in RES integrated systems. The wide range of potential sources includes wind turbines, solar photovoltaic plant, energy storage, high voltage direct current (HVDC) systems, and demand response. The challenges and limitations associated with each approach are highlighted, and alternative strategies to maintain a minimum volume of security constrained fast frequency reserve are discussed based on the recent industry trends. [ABSTRACT FROM AUTHOR]

Aims and background: Patients with benign prostatic hyperplasia (BPH) may receive prostatic surgery due to severe lower urinary tract symptoms (LUTS). This study aimed to investigate the health-related quality of life (HRQoL), psychological well-being, and sexual function of patients with BPH after prostatic surgery and identify the predictors of HRQoL among this group of patients. Methods: This was a cross-sectional, descriptive, correlational study. A convenience sample of 94 participants was recruited from a urology center in a tertiary public hospital in Singapore. The 12-item Short Form Health Survey version 2 (SF-12v2), International Prostate Symptom Score (IPSS), Hospital Anxiety and Depression Scale (HADS), and 5-item International Index of Erectile Function (IIEF-5) were used to measure the study variables. Results: Compared to the general population norms and the findings of similar studies conducted in western countries, this group of patients reported poorer physical health but better mental health as assessed by SF-12v2. Despite the prostatic surgery, over a quarter of the patients experienced moderate LUTS, and 13.8% experienced severe erectile dysfunction. Multiple linear regression analysis identified that LUTS (B = -0.51, p = 0.02) and maximum flow rate (B = -0.23, p = 0.02) predicted poor physical health, accounting for 45.9% of variance, while HADS-Anxiety (B = -1.07, p < 0.01) and LUTS (B = -0.32, p = 0.03) predicted poor mental health, accounting for 57.2% of variance. Conclusion: The physical health of BPH patients with prostatic surgery was poor, with many suffering moderate LUTS and sexual dysfunction. Special attention should be given to those patients with severe LUTS who have a low maximum flow rate or have anxiety symptoms. [ABSTRACT FROM AUTHOR]

The present experimental study was conducted to determine the effects of xylanase supplementation on growth performance, nutrient digestibility and digestive enzyme activities of mori, Cirrhinus mrigala. Mori with an initial body weight of 8.34 ± 0.23 g were fed seven experimental diets: a diet with high fish meal content (positive control, PC), a diet with high plant content (negative control, NC), and five other diets with increasing levels of xylanase (680, 1273, 1882, 2486 and 3091 U/kg). Each diet was fed to triplicate groups of 15 fish each for 60 days. After the trial termination, supplementation of xylanase significantly improved final weight (FW), weight gain (WG) and specific growth rate (SGR) compared to NC diet. The best feed conversion ratio (FCR) was observed at 1882 U/kg of xylanase supplementation level which was non-significant (P > 0.05) to PC diet (high fish meal content). Whole body proximate composition and apparent digestibility coefficient (ADC%) for dry matter (DM), crude protein (CP), crude fat (CF), crude ash (CA) and gross energy (GE) were significantly affected by xylanase supplementation. Activities of hepatopancreatic and intestinal amylase, protease and lipase showed an increasing trend with the increase in xylanase supplementation level, peaking at 1882 U/kg of xylanase (non-significant (P > 0.05) to PC diet) and declining thereafter (2486 U/kg-3091 U/kg). Quadratic regression analysis showed that 1948 U/kg of xylanase was the optimum value for supplementation of xylanase in plant-based diet. In conclusion, exogenous xylanase supplementation improved the growth performance, nutrient digestibility and digestive enzyme activities in juvenile mori fed plant-based diet. • First article to focus on xylanase supplementation on juvenile mori (Cirrhinus mrigala). • Exogenous xylanase improves growth performance, nutrient digestibility and digestive enzyme activities. • Quadratic regression analysis for weight gain% (WG%) showed that 1886 U/kg of xylanase was the optimum value for supplementation of xylanase in plant meal based diet. [ABSTRACT FROM AUTHOR]

• A novel approach based on the Agglomerative hierarchical clustering technique has been proposed for optimal cabling of OWF. • Reliability and economic indices are considered for the section of optimal WT clusters in the OWF. • Availability and economic analysis of MTDC connected OWF clusters has also been performed. • The analysis shows that the meshed MTDC topology is most reliable, whereas the multi-terminal topology is more economical. The advancement of technologies has shifted focus from onshore to offshore wind farms (OWFs) to extract the maximum benefit out of wind resources. Capital investment for OWFs is high; hence, proper planning is inevitable to utilize resources efficiently. This paper proposes a novel two-level planning approach, where in the first level, optimal cable connection of OWFs has been determined. In the second level, reliability and economic evaluation of different configurations of high voltage DC (HVDC) connected OWFs have been studied. Three OWFs of different shapes and ratings, however, with the same wind profile and connected to onshore voltage source converter- HVDC (VSC- HVDC) platform through HVDC link, have been considered in this study. In the first level, the placement of wind turbines (WTs) in the individual OWF is optimized using particle swarm optimization. Following that, an optimal combination of WT clusters of OWFs is obtained using the agglomerative hierarchical clustering technique. In this context, two objectives, such as economy and reliability have been considered. The traveling salesman problem is formulated to obtain minimized cable lengths inside each WT cluster of the OWF. The cost of submarine cable is used to evaluate the economic aspect, whereas expected energy not supplied (EENS) is taken as the reliability index. A sequential Monte Carlo method has been developed to calculate EENS considering random outage of WTs and cables. In the next level, an economic and reliability assessment of the entire multi-terminal DC (MTDC) OWF cluster is performed. Economic assessment is performed considering the total cost of different MTDC components, whereas, forced outage of the components is considered to assess the reliability index. A comparative study of different connection topologies of MTDC OWF configurations shows that mesh connection has the highest reliability and availability (94.97 %). On the other hand, multi-terminal topology has the least investment cost which is 12.40 % and 7.51 % more economical compared to mesh and radial topology respectively. [ABSTRACT FROM AUTHOR]

In the modern-day distribution network, converter-based distributed generators (DGs) are increasingly employed to supply power from renewables. One of the prominent issues in the use of decentralized control for this purpose is the inaccurate real power sharing amongst these DGs due to the voltage drops associated with the feeder/line impedances. The use of virtual voltage drop in the controller of these DGs is a popular approach to mitigate the impedance mismatch effects. This impedance shaping technique demonstrates improved power sharing, however, the selection of an appropriate value for it is a big challenge. This paper elaborates upon a droop-based VI shaping technique for converter-based DG through a non-linear variation for islanded networks which are predominantly resistive. Performance evaluation of this technique for a wide variety of loads including balanced (constant impedance), constant power, unbalanced, non-linear, and induction motor loads is done through detailed simulations. The proposed method is also tested for a mesh network. DG plug-and-play functionality performance and load variation on a modified 13-bus network is verified using the proposed control scheme. The range for control parameters for stability is verified through modeling and eigen value analysis. Experimental validation on a laboratory setup for the same has also been presented. • A non-linear relation between the output current and virtual impedance values is proposed to improve the proportional power-sharing of the DGs. • Improved proportional power-sharing is achieved by keeping the PCC voltage under acceptable limits and the non-linear parameter is also adjusted automatically. • The scheme idea is designed for low-voltage islanded systems and isolated systems where the DGs operate in inverse drop control. [ABSTRACT FROM AUTHOR]

This study describes the clinical characteristics and outcomes of hospitalized patients with 2009 H1N1 influenza in a large, acute care, tertiary hospital in Singapore. Of the 265 hospitalized patients with laboratory-confirmed 2009 influenza A (H1N1) during the height of the H1N1 flu pandemic, 13% (35) suffered severe outcomes including a mortality rate of 4.5% (12). Severe outcomes were associated with patients aged 40 years or more, underlying comorbidities, and complicated by pneumonia. [Copyright &y& Elsevier]

Background: Worldwide, the frequency of invasive fungal infections has been increasing, with a corresponding increase in the numbers of high-risk patients. Exposure reduction through the use of high-efficiency particulate air (HEPA) filters has been the preferred primary preventive strategy for these high-risk patients. Although the efficiency and benefits of fixed HEPA filters is well proven, the benefits of portable HEPA filters are still inconclusive. Methods: This was a retrospective study to assess the impact of 48 portable HEPA filter units deployed in selected wards in Singapore General Hospital, an acute tertiary-care hospital in Singapore. Data were extracted between December 2005 and June 2008 on the diagnoses at discharge and microbiological and histological laboratory findings. All patients with possible, probable, or proven invasive aspergillosis (IA) were included. Results: In wards with portable HEPA filters, the incidence rate of IA of 34.61/100,000 patient-days in the preinstallation period was reduced to 17.51/100,000 patient-days in the postinstallation period (P = .01), for an incidence rate ratio of 1.98 (95% confidence interval [CI], 1.10-2.97). In wards with no HEPA filters, there was no significant change in the incidence rate during the study period. Portable HEPA filters were associated with an adjusted odds ratio of 0.49 (95% CI, 0.28-0.85; P = .01), adjusted for diagnosis and length of hospital stay. Conclusions: Portable HEPA filters are effective in the prevention of IA. The cost of widespread portable HEPA filtration in hospitals will be more than offset by the decreases in nosocomial infections in general and in IA in particular. [Copyright &y& Elsevier]

The low fault current contribution from inverter-interfaced distributed generators (IIDGs) and bidirectional flow of current in the power networks introduces protection challenges when islanded. The existing fault detection scheme based on the transient monitoring function (TMF) fails under such scenarios. A new decentralised machine learning (ML) based fault detection and classification scheme is proposed in this paper using terminal voltage information of IIDG (v o−abc). TMF of v o−abc , along with the zero sequence component of v o−abc , is utilised for training and testing of ensemble bagged trees ML algorithm. The proposed scheme is implemented inside each IIDG, and hence, it does not require communication. It is validated on a modified CIGRE test benchmark microgrid for all shunt faults at various locations with different loading, fault resistances, and inception angles. The accuracy of detection and classification of fault (DCF) during fault cases with unbalanced loads, noise, harmonic loads, and no-fault scenarios such as load and DG switching proves the effectiveness of the proposed method with varying scenarios. The performance of the proposed scheme is found to be superior when compared with the existing threshold based TMF and Hilbert–Huang transform (HHT) based techniques considering accuracy, dependability, security, and response time. • Queries by all the reviewer 3 are addressed in details. • Made suitable changes to the introduction to bring in more clarity. [ABSTRACT FROM AUTHOR]

Maize is a globally significant food crop but its future sustainability under rainfed conditions is at risk due to climate change and increased climate uncertainty. In Pakistan most maize is rainfed but there is increasing interest in the role of supplemental irrigation to reduce the vulnerability of crop yields to future drought and climate risks. Using a crop model (DSSAT CERES-Maize) with downscaled data from a weather generator (LARS-WG) and for five selected GCMs, two RCPs (4.5 and 8.5) and two time slices (2050s and 2080s), this study assessed the impacts of climate change and climate variability on rainfed maize grown in the Pothwar region of Pakistan, and the extent to which irrigation could offset future yield reductions. Model simulations were calibrated and validated using experimental data from 2021 and 2022. The outputs showed that on average the yield of maize could be increased by 55% with a single irrigation of 60 mm during the reproductive stage. For the baseline (1991–2020) the average rainfed yield was 3370 kg/ha. The climate change scenarios for the 2050s indicated a −13.5% and −5.8% decline in rainfed yield under RCP4.5 and RCP8.5, respectively. Irrigation applications (between 162 mm and 180 mm) increased grain yields by 5615 kg/ha and 5732 kg/ha, respectively. For the 2080s scenarios there was a projected decrease in yield by - 9.3% and - 39.7% under RCP4.5 and RCP8.5, respectively. Modelling also confirmed significant reductions in maize biomass production which would negatively impact on feedstocks for both livestock and renewable energy generation. • Supplemental irrigation can increase maize yields by up to 55% in the Pothwar region. • Climate change will increase dependence on supplemental irrigation to ensure future maize production is sustainable. • Policy reforms to support improved irrigation management are needed to avoid significant economic losses. [ABSTRACT FROM AUTHOR]

Abstract: Background: Among other risk factors, renal disease and ethnicity have been associated with diabetic lower extremity amputation (LEA) in Western populations. However, little is known about risk factors for LEA among Asian patients. Objective: The objective was to assess the proportion of hospitalized patients with diabetes who have a LEA among all hospital patients with diabetes mellitus (DM) and to investigate risk factors for diabetic LEA (especially renal disease and ethnicity) using hospital discharge database. Method: A retrospective study of hospital discharge database (2004–2009) was performed to identify patients with DM, LEA and renal disease using the International Statistical Classification of Diseases and Related Health Problems, Ninth Revision, Australian Modification codes. Results: Of 44 917 hospitalized patients with DM during the 6 years, 7312 (16.3%) patients had renal disease, and 1457 (3.2%) patients had LEA. DM patients with renal disease had significant higher rates of LEA (7.1%) compared to DM patients without renal disease (2.5%, P<.001). The differences were present for foot (2.7% vs. 1.2%), ankle or leg (2.8% vs. 0.9%), and knee or above amputation (1.6% vs. 0.4%, all P<.001). Malays had the highest rate of diabetic LEA (5.1%), followed by Indians (3.0%), Chinese (3.0%), and others (2.3%, P<.001). In logistic regression analyses, renal disease and ethnicity were significant predictors of diabetic LEA (renal disease: odds ratio 3.2, 95% confidence interval 2.8–3.6; ethnicity: odds ratio, 1.6, Malays vs. Chinese, P<.001; 1.0, Indians vs. Chinese, P=.784) after adjustment for age, gender, and year of discharge. Conclusion: DM patients with renal disease and Malay ethnicity had higher rates of LEA in this Asian patient population. Malay patients with DM and diabetic patients with renal disease should be considered as high-risk groups for LEA and therefore screened and monitored systematically. [Copyright &y& Elsevier]