Optimal Level Research Articles

Optimal management of international reserves

AbstractThis article develops a continuous time stochastic model for determining the optimal international reserves management policy when the data generating process of international reserves is a geometric Brownian motion. The policy is a two‐parameter control‐limit that consists of an appropriate and a ceiling level on reserves holdings, given an exogenous floor on international reserves. The optimal solution is determined so as to minimize the total costs of international reserves holdings. It is proved that our results extend the framework of Frenkel and Jovanovic when the logarithm of international reserves is an arithmetic Brownian motion. We also explain that Jung paper does not extend Frenkel and Jovanovic model as claimed by the former. The model is calibrated to derive the optimal level and liquidity tranche size upper bound of international reserves of the CEMAC monetary union.

Role of senataxin in R-loop-mediated neurodegeneration.

Senataxin is an RNA:DNA helicase that plays an important role in the resolution of RNA:DNA hybrids (R-loops) formed during transcription. R-loops are involved in the regulation of biological processes such as immunoglobulin class switching, gene expression and DNA repair. Excessive accumulation of R-loops results in DNA damage and loss of genomic integrity. Senataxin is critical for maintaining optimal levels of R-loops to prevent DNA damage and acts as a genome guardian. Within the nucleus, senataxin interacts with various RNA processing factors and DNA damage response and repair proteins. Senataxin interactors include survival motor neuron and zinc finger protein 1, with whom it co-localizes in sub-nuclear bodies. Despite its ubiquitous expression, mutations in senataxin specifically affect neurons and result in distinct neurodegenerative diseases such as amyotrophic lateral sclerosis type 4 and ataxia with oculomotor apraxia type 2, which are attributed to the gain-of-function and the loss-of-function mutations in senataxin, respectively. In addition, low levels of senataxin (loss-of-function) in spinal muscular atrophy result in the accumulation of R-loops causing DNA damage and motor neuron degeneration. Senataxin may play multiple functions in diverse cellular processes; however, its emerging role in R-loop resolution and maintenance of genomic integrity is gaining attention in the field of neurodegenerative diseases. In this review, we highlight the role of senataxin in R-loop resolution and its potential as a therapeutic target to treat neurodegenerative diseases.

Influence of FexOy and Al2O3 Contents on the Thermal Stability of Iron Ore-Waste Fibers: Key Mechanisms and Control.

Traditional rock wool fibres are susceptible to crystallization and pulverization. To mitigate this, glass fibres were produced from iron ore waste (IOW). When the ratio of Fe2+ and Fe3+ is 1:3 and the Al2O3 content is 10 wt.%, increasing the FexOy content enhances the thermal stability.At an FexOy content of 17-19% and an Al2O3 content of 10-13%, the glass transition temperature (Tg) peaked. Increasing the FexOy content from 10% to 20% enhanced the stability of Si-O and Al-O bonds and increased bridged oxygen, stabilizing the structure. Here, Fe2+ balances structural charges, while Fe3+ replaces some Al atoms in the network. When the Al2O3 content is 10-13% and the FexOy content is 17-19%, the thermal stability of the IOW rock glass reaches its optimal level. At 20% FexOy content, the structure becomes three-dimensional and cyclic, increasing polymerization. Consequently, incorporating FexOy alongside a 10% Al2O3 content improves thermal stability, supporting the development of high-stability rock wool from IOW. This approach also enhances the refractory properties of rock wool fibres within the FexOy-Al2O3-SiO2-MgO-CaO system.

The Risk of Atrial Fibrillation and Previous Ischemic Stroke in Cognitive Decline.

Objectives: Our study investigated the inverse relationship between cognitive decline (CD) and the presence of documented atrial fibrillation (AFib), ischemic stroke, heart failure, lower extremity peripheral artery disease, and diabetes mellitus. Methods: We conducted a retrospective cross-sectional study between December 2016 and November 2019. A total of 469 patients were enrolled who underwent cognitive evaluation with three cognitive tests (Montreal Cognitive Assessment-MOCA, Mini-Mental State Examination-MMSE, and General Practitioner Assessment of Cognition-GPCOG). We used the standard cut-off values, and the optimal thresholds were obtained from the receiver operating characteristic curves. Results: The standard cut-off level of the MOCA (<26 points) was associated with the presence of AFib (OR: 1.83, 95% CI: 1.11-3.01) and the optimal cut-off level with <23 points with ischemic stroke (OR: 2.64, 95% CI: 1.47-4.74; p = 0.0011). The optimal cut-off value of the MMSE (<28 points) was associated with the presence of ischemic stroke (OR: 3.07, 95% CI: 1.56-6.07; p = 0.0012), AFib (OR: 1.65, 95% CI: 1.05-2.60; p = 0.0287), and peripheral artery disease (OR: 2.72, 95% CI: 1.38-5.36; p = 0.0039). GPCOG < 8 points were associated with ischemic stroke (OR: 2.18, 95% CI: 1.14-4.14; p = 0.0176) and heart failure (OR: 1.49, 95% CI: 1.01-2.21; p = 0.0430). Conclusions: Our research highlighted the broader utility of cognitive assessment. The MOCA and MMSE scores proved to be associated with documented AFib. Higher cognitive test results than the standard threshold for CD of the MMSE, GPCOG, and lower MOCA scores represented risk factors for the presence of previous ischemic stroke.

Optimal reserve policies for emergency medical supplies: Joint consideration of reserving safety stocks, production capacity, and capital

The tragic consequences of the COVID-19 epidemic highlight to governments the importance of keeping sufficient medical supplies. Given that the physical stocks are subject to considerable obsolescence risk, existing studies have considered combining holding safety stocks with keeping production capacity or capital reserve. Pioneering the exploration of keeping all three resources of safety stocks, production capacity, and capital in reserve, we derive closed-form optimal reserve policies under different scenarios. One crucial insight is that the optimal reserve policies should be determined by considering both the cost and utilization efficiency, e.g., solely adopting safety stocks is optimal when the utilization efficiency of safety stocks exceeds that of production capacity and capital reserves, and when the expected benefit of utilizing safety stocks outweighs the cost. Additionally, we find that the optimal safety stocks level is impacted by the combination of demand uncertainty and epidemic outbreak probability, i.e., the optimal safety stocks level decreases (resp., increases) with demand uncertainty in case with a sufficiently low (resp., high) epidemic outbreak probability, whereas the optimal levels of production capacity and capital always increase with demand uncertainty. We show that coordinating the three resources brings extra benefits compared with keeping fewer resources. By exploring the practical scenario where the government faces multiple potential epidemics, we find that below a threshold, a lower outbreak probability of a large-scale epidemic leads to more capital and production capacity reserves.

Impact and Interrelationships of Striatal Proteins, EPHB2, OPRM1, and PER2 on Mild Cognitive Impairment.

With the global increase in life expectancy, there has been a rise in the incidence of cognitive impairments attributed to diverse etiologies. Notably, approximately 50% of individuals diagnosed with mild cognitive impairment (MCI) progress to dementia within 3years. However, the precise mechanisms underlying MCI remain elusive. Therefore, this study aimed to elucidate potential mechanisms implicated in MCI utilizing Per2 knockout (KO) mice, which have previously been shown to have cognitive deficits. Behavioral (Y-maze, Barnes maze) and molecular (electrophysiology, RNA sequencing, western blot, and immunofluorescence) experiments were conducted in Per2 KO and wild-type (WT) mice. Per2 KO mice exhibited impaired spatial working memory in the Y-maze and Barnes maze. However, there were no significant group differences in hippocampal long-term potentiation (LTP) between Per2 KO and WT mice, whereas striatal LTP in Per2 KO mice was lower compared to WT mice. In RNA sequencing analysis, 58 genes were downregulated and 64 genes were upregulated in the striatum of Per2 KO mice compared to WT mice. Among the differentially expressed genes, four genes (Chrm2, EphB2, Htr1b, Oprm1) were identified. Optimal expression levels of EPHB2 and OPRM1 were found to significantly enhance cognitive performance in mice. Additionally, Per2 KO mice exhibited reduced EPHB2-NMDAR-LTP and OPRM-mTOR signaling, along with elevated amyloid beta (Aβ) levels, when compared to WT mice. However, these alterations were reversed upon administration of morphine treatment. Striatal OPRM1-mTOR signaling, EPHB2-NMDAR-LTP signaling, and Aβ expression levels may exert a combined effect on MCI under the control of Per2 expression.

Production of sustainable GGBFS-based Self-Compacting Geopolymer Concrete containing E-waste aggregates under ambient temperature curing

Geopolymer concrete (GPC) has gained global attention due to its environmentally friendly composition and a reduction in the carbon footprint compared to conventional concrete. Self-compacting geopolymer concrete (SCGC) combines the environmental benefits of geopolymers with the convenience of self-compacting concrete (SCC), offering a sustainable solution that minimizes manual labor, reduces noise pollution, and ensures a high-quality finish in diverse construction locations. The rapid proliferation of electronic devices in contemporary society has substantially enhanced electronic waste (e-waste), creating significant environmental challenges. This study explores a sustainable approach in managing the menace created by e-waste through its partial replacement against natural aggregates in producing ground granulated blast furnace slag (GGBFS)-based SCGC under ambient temperature curing. The research methodology involves the preparation of eleven mixes, including the control SCGC mix (with no e-waste aggregate), utilizing printed circuit boards (PCBs) as partial replacement in natural fine and coarse aggregates at varying percentages, i.e., 10 %, 20 %, 30 %, 40 %, and 50 %. It is revealed through a detailed fresh property, mechanical property, durability property, and microstructural analysis that the optimal replacement levels with e-waste are 30 % NFA or 10 % NCA in producing a sustainable and workable SCGC comprising 28.2 % and 19.2 % of waste materials (GGBFS, EWF, and EWC) moving towards a sustainable concrete yield.

Ascorbate insufficiency disrupts glutamatergic signaling and alters electroencephalogram phenotypes in a mouse model of Alzheimer's disease

Clinical studies have reported that increased epileptiform and subclinical epileptiform activity can be detected in many patients with an Alzheimer's disease (AD) diagnosis using electroencephalogram (EEG) and this may correlate with poorer cognition. Ascorbate may have a specific role as a neuromodulator in AD as it is released concomitantly with glutamate reuptake following excitatory neurotransmission. Insufficiency may therefore result in an exacerbated excitatory/inhibitory imbalance in neuronal signaling. Using a mouse model of AD that requires dietary ascorbate (Gulo−/-APPswe/PSEN1dE9), EEG was recorded at baseline and during 4 weeks of ascorbate depletion in young (5-month-old) and aged (20-month-old) animals. Data were scored for changes in quantity of spike trains, individual spikes, sleep-wake rhythms, sleep fragmentation, and brainwave power bands during light periods each week. We found an early increase in neuronal spike discharges with age and following ascorbate depletion in AD model mice and not controls, which did not correlate with brain amyloid load. Our data also show more sleep fragmentation with age and with ascorbate depletion. Additionally, changes in brain wave activity were observed within different vigilance states in both young and aged mice, where Gulo−/-APPswe/PSEN1dE9 mice had shifts towards higher frequency bands (alpha, beta, and gamma) and ascorbate depletion resulted in shifts towards lower frequency bands (delta and theta). Microarray data supported ascorbate insufficiency altering glutamatergic transmission through the decreased expression of glutamate related genes, however no changes in protein expression of glutamate reuptake transporters were observed. These data suggest that maintaining optimal brain ascorbate levels may support normal brain electrical activity and sleep patterns, particularly in AD patient populations where disruptions are observed.

Procurement practices and operational performance: a study of linear and curvilinear relationships in a developing economy

PurposeWhile operational performance is important for a company's competitiveness and profitability, this study claims that procurement may be required to drive operational performance. This study aims to focus on how procurement practices is related to operational performance among selected manufacturing firms.Design/methodology/approachThe model was tested on a sample of 329 manufacturing firms in clothing and textiles, chemicals and plastics, food and beverages processing, wood processing, metal processing and pharmaceutical manufacturing industries in a developing economy.FindingsThe results indicate that firms with higher and optimal level of procurement practices achieve higher levels of operational performance. Regardless of the H1 rationale, this study suggests that increasing procurement techniques has a limit in terms of improving operational performance. This study establishes that extreme level of procurement practices is associated with decreasing operational performance.Practical implicationsThis study calls attention to how managers can guide organizations in refining their procurement strategies and practices; there is the need to strive to strike a balance between diversification and efficiency in procurement.Social implicationsManufacturing firms are often integral parts of local communities. The decisions they make regarding procurement practices can impact the economic health of these communities. Striking a balance between diversification and efficiency can contribute to sustainable business practices that benefit both the company and the local community.Originality/valueAs the main contribution, this study brings the additional perspective that extreme level of procurement practices is associated with decreasing operational performance.

Corporate financialization and litigation risk

This study empirically analyses the impact of corporate financialization on litigation risk and finds that there is a U-shaped relationship between corporate financialization and litigation risk, whereby an increase in the level of financialization reduces litigation risk before a firm's level of financialization reaches the optimal level, and an increase in the level of financialization exacerbates litigation risk after a firm's level of financialization exceeds the optimal level.

Graves' Disease in Hypopituitarism Due to Pituitary Apoplexy.

Central hypothyroidism and autoimmune hyperthyroidism are contrasting pathologies requiring careful hormone monitoring for restoring euthyroidism. Their coexistence is rare and challenging for clinicians [1, 2]. We have, herein, presented the case of a 41-year-old female patient with an unremarkable clinical history except for chronic autoimmune thyroiditis in euthyroidism. At the 21st week of gestation, she experienced a spontaneous abortion. The patient underwent an assessment of the uterine cavity, which was complicated by bleeding and hypotensive shock. In the postoperative course, the patient presented worsening headache, and after an MRI, the diagnosis of pituitary apoplexy due to an ischemic-hemorrhagic base was made. Laboratory tests showed anterior panhypopituitarism. Multiaxial replacement therapy was initiated with hydrocortisone, levothyroxine (LT4), and subsequently estrogen-progestin and GH. After two years of good recovery with stable LT4 dosage, the patient experienced palpitations and fine tremors; blood tests showed hyperthyroidism with suppressed Thyroid-stimulating Hormone (TSH) levels and elevated free thyroid fractions and anti-TSH receptor antibodies. Diagnosis of Graves' disease was made, and therapy with methimazole was initiated. During antithyroid therapy, TSH remained persistently suppressed, consistent with the underlying central hypothyroidism. This condition required close follow-up, with monitoring based solely on free thyroid hormone levels. After six months of antithyroid therapy, disease remission was achieved, with negative antibodies and mild hypothyroxinemia. Therefore, methimazole was discontinued and replacement therapy gradually resumed until optimal hormone levels were reached. This case is unique demonstrating autoimmune hyperthyroidism to coexist with central hypothyroidism, rendering TSH a misleading disease progression indicator. Consequently, managing Graves' disease has become more complex and challenging.

Experimental investigation of a transcritical CO2 refrigeration system incorporating rotary gas pressure exchanger and low lift ejectors

Natural refrigerants like CO2 are playing a significant role in making refrigeration and heat pump systems climate-friendly by slowly phasing out the high global warming refrigerants like hydrofluorocarbons (HFCs). However, the efficiency of a transcritical CO2 refrigeration system declines significantly when the ambient temperature increases, primarily attributed to the high-pressure lift and the losses incurred during expansion. To remedy this issue, this paper presents a novel rotary gas pressure exchanger (PXG) device, which simultaneously achieves high differential pressure expansion work recovery and the “free compression” of the portion of the flash gas in a compact, rotary machine. For this, a PXG device is designed, fabricated, and tested to achieve free compression of CO2 over the entire differential pressure of approximately 70 bar between a receiver and a gas cooler. This is one of the highest free-pressure lift provided by any device to date in CO2 refrigeration. However, there is a small pressure loss of approximately 1–2 bar in the system due to viscous and inertia losses in the piping and in the PXG itself, which needs to be overcome by an external booster device. Results on a baseline PXG integrated system with two low lift booster compressors are presented, which show up to 60 bar free pressure lift and up to 18.2 % COP improvement provided by PXG. Additionally, key performance characteristics of the PXG, like the expansion work recovery, the mass boost ratio, direct fluid-to-fluid contact, and no pass-through operation are experimentally quantified. This work also presents a novel method to integrate two low lift ejectors with PXG to eliminate the need for separate low lift compressors. The low lift ejectors are designed, fabricated, and tested in-house, followed by their integration with the PXG device. A new type of transcritical CO2 refrigeration system is designed to integrate these low lift ejectors with PXG, and experiments are conducted at various evaporator thermal duties and gas cooler exit temperatures, simulating varying ambient temperature conditions. A novel control system to control the gas cooler pressure to optimal thermodynamic levels using PXG rotational speed is demonstrated experimentally. Further, automated control of high-pressure low lift ejector mass flow using an in-built needle design has been successfully demonstrated to optimise PXG mass boost performance. The LP low lift ejector achieved a successful pressure lift of 3.8 bar, and the HP low lift ejector showed a lift of 5.7 bar on the top of 42 bar free pressure lift provided by PXG for up to 5.8 kg/min mass flow delivered by free PXG compression. The results from this study demonstrate that the PXG device provides a significant energy efficiency improvement to the transcritical CO2 refrigeration system, and the novel low lift ejectors, when integrated with PXG, provide a successful method to maximise PXG’s thermodynamic potential.

Appropriate Mother Wavelet Selection with Optimum Level of Disintegration for Analyzing Various Faults of Induction Motor Under Variation in Motor Loading

Appropriate Mother Wavelet Selection with Optimum Level of Disintegration for Analyzing Various Faults of Induction Motor Under Variation in Motor Loading

Synergistic Dynamical Decoupling and Circuit Design for Enhanced Algorithm Performance on Near-Term Quantum Devices.

Dynamical decoupling (DD) is a promising technique for mitigating errors in near-term quantum devices. However, its effectiveness depends on both hardware characteristics and algorithm implementation details. This paper explores the synergistic effects of dynamical decoupling and optimized circuit design in maximizing the performance and robustness of algorithms on near-term quantum devices. By utilizing eight IBM quantum devices, we analyze how hardware features and algorithm design impact the effectiveness of DD for error mitigation. Our analysis takes into account factors such as circuit fidelity, scheduling duration, and hardware-native gate set. We also examine the influence of algorithmic implementation details, including specific gate decompositions, DD sequences, and optimization levels. The results reveal an inverse relationship between the effectiveness of DD and the inherent performance of the algorithm. Furthermore, we emphasize the importance of gate directionality and circuit symmetry in improving performance. This study offers valuable insights for optimizing DD protocols and circuit designs, highlighting the significance of a holistic approach that leverages both hardware features and algorithm design for the high-quality and reliable execution of near-term quantum algorithms.

Mechanisms of Flavonoids and Their Derivatives in Endothelial Dysfunction Induced by Oxidative Stress in Diabetes.

Diabetic complications pose a significant threat to life and have a negative impact on quality of life in individuals with diabetes. Among the various factors contributing to the development of these complications, endothelial dysfunction plays a key role. The main mechanism underlying endothelial dysfunction in diabetes is oxidative stress, which adversely affects the production and availability of nitric oxide (NO). Flavonoids, a group of phenolic compounds found in vegetables, fruits, and fungi, exhibit strong antioxidant and anti-inflammatory properties. Several studies have provided evidence to suggest that flavonoids have a protective effect on diabetic complications. This review focuses on the imbalance between reactive oxygen species and the antioxidant system, as well as the changes in endothelial factors in diabetes. Furthermore, we summarize the protective mechanisms of flavonoids and their derivatives on endothelial dysfunction in diabetes by alleviating oxidative stress and modulating other signaling pathways. Although several studies underline the positive influence of flavonoids and their derivatives on endothelial dysfunction induced by oxidative stress in diabetes, numerous aspects still require clarification, such as optimal consumption levels, bioavailability, and side effects. Consequently, further investigations are necessary to enhance our understanding of the therapeutic potential of flavonoids and their derivatives in the treatment of diabetic complications.

Association between composite dietary antioxidant index and hyperlipidemia: a cross-sectional study from NHANES (2005–2020)

The association between the composite dietary antioxidant index (CDAI) and hyperlipidemia remains unclear. Therefore, this study aimed to investigate the relationship between CDAI and hyperlipidemia. The data used in this study were obtained from the National Health and Nutrition Examination Survey (NHANES) dataset spanning from 2005 to 2020. Based on 24-h dietary recall interviews, the CDAI was calculated using the intake of six dietary antioxidants. Univariate and multivariate logistic regression models were employed to investigate the relationship between CDAI and the occurrence of hyperlipidemia. Additionally, restricted cubic spline (RCS) analysis was utilized to investigate potential non-linear relationships between the CDAI and risk of hyperlipidemia. The final analysis included 30,788 adults in the United States, among whom 25,525 (82.91%) were diagnosed with hyperlipidemia. A significant negative correlation was observed between the CDAI and hyperlipidemia in the unadjusted (Odds ratio [OR] 0.97 [95% CI 0.96, 0.98]) and multi-variable adjusted (OR 0.98 [95% CI 0.97, 0.99]) models. When the CDAI values were analyzed as a categorical variable, individuals in the highest quartile (OR 0.82 [95% CI 0.73, 0.92]) exhibited a nearly one fifth decreased risk of hyperlipidemia compared to those in the lowest quartile. Additionally, RCS analysis revealed a linear relationship between CDAI and hyperlipidemia (P for nonlinearity = 0.124). The results remained consistent across subgroups except for individuals under the age of 60 or those with diabetes mellitus. There was a significant negative correlation between the CDAI and risk of hyperlipidemia, indicating that maintaining an optimal CDAI level could effectively reduce the incidence of hyperlipidemia.

A High Voltage Symmetric Supercapacitor Comprising Concentrated NaCl: PVA Electrolyte and Partially Reduced Graphene Oxide Electrodes

AbstractStrategies to improve energy density in supercapacitors are mainly based on utilizing electrodes providing larger effective surfaces and electrolytes allowing op eration in wider voltage windows. Here, a water‐based, binder‐free, environmentally friendly, high voltage, and quasi‐solid‐state symmetric supercapacitor is presented comprising partially reduced graphene oxide active electrodes and concentrated NaCl: polyvinyl alcohol gel electrolyte. It is shown that the ionic diffusion through the electrode‐electrolyte interface is augmented by the partial reduction of the graphene oxide electrodes up to an optimum level. The safe operation voltage window is 4 V; the high field endurance is attributed to the ion‐saturated hydrogel electrolyte used. At a scan rate of 25 mV/s, the provided capacitance and stored energy are 0.1 F.cm−2 and 5.6 e−5 W.h.cm−2, respectively. The optimized device retains ~90 % of its initial capacitance after 1000 charge‐discharge cycles; no meaningful sign of degradation is detected afterwards up to the 2000 cycles examined. These results place further emphasis on the potentials of the gel polymer electrolytes in the fabrication of environmentally friendly supercapacitors. Our findings are anticipated to accelerate improvements in the properties of the graphene‐based electrodes, particularly in conjunction with the proposed electrolyte.

Forecasting the parameters of performance monitoring of complex technical systems

The problem of monitoring the performance of technical systems is considered, corresponding to the stage of final control during the production of a product, as well as the stage of testing the product before its use. Based on the generalization and development of the existing approaches, models and methods for monitoring the performance of complex technical systems were developed, and models for predicting the parameters of their control were proposed. Methods of optimizing the number of tests of units of technical systems when monitoring their performance were developed. Methods for estimating the optimal level of the total defect rate are proposed. The efficiency of the proposed approaches is illustrated using a specific numerical example. The methods and models presented in the article can be useful for engineering and technical workers of design bureaus, research institutes, research and production associations and enterprises in ensuring the reliability of products and technical systems.

Optimizing germination conditions of Ghaf seed using ZnO nanoparticle priming through Taguchi method analysis

Ghaf, a resilient tree in arid environments, plays a critical role in ecological restoration, desertification mitigation, and cultural heritage preservation. However, the seeds’ inherent challenges, notably their hard outer coating restricting germination, emphasize the pressing need for innovative strategies. This work aimed to investigate the optimization of Ghaf seed germination process through seed priming with ZnO nanoparticles treatment (duration (t), concentration (c), temperature (T), and agitation (a), employing the Taguchi method for efficient experimental design. Furthermore, the study includes Analysis of Variance (ANOVA), analysis for the regression model to assess the significance of predictor variables and their interactions, thereby strengthening the statistical validity of our optimization approach. Notably, it revealed that concentration is a pivotal influencer in optimization of Ghaf seed germination. The results showed that the concentration of ZnO nanoparticles has no linear relation with any other parameters. To verify the outcomes, validation tests were performed utilizing the predicted optimal parameters. The observed low error ratio, falling within the range of 1 to 6%, confirmed the success of the Taguchi methodology in identifying optimal levels of the factors chosen. Significantly, ZnO-primed seeds showcased a remarkable enhancement in Ghaf seed germination, increasing from 15 to 88%. This study introduces a novel approach utilizing ZnO nanoparticle treatment optimized through the Taguchi method, significantly enhancing seed germination rates of Ghaf seeds and offering a promising avenue for sustainable agricultural practices in arid environments.

Optimal Significance Levels and Sample Sizes for Signal Detection Methods Based on Non-constant Hazards.

Statistical methods for signal detection of adverse drug reactions (ADRs) in electronic health records (EHRs) need information about optimal significance levels and sample sizes to achieve sufficient power. Sauzet and Cornelius proposed tests for signal detection based on the hazard functions of Weibull type distributions (WSP tests) which use the time-to-event information available in EHRs. Optimal significance levels and sample sizes for the application of the WPS tests are derived. A simulation study was performed with a range of scenarios for sample size, rate of event due (ADRs), and not due to the drug and random time to ADR occurrence. Based on the area under the curve of the receiver operating characteristic graph, we obtain optimal significance levels of the different WSP tests for the implementation in a hypothesis free signal detection setting and approximate sample sizes required to reach a power of 80% or 90%. The dWSP-pPWSP (combination of double WSP and power WSP) test with a significance level of 0.004 was recommended. Sample sizes needed for a power of 80% were found to start at 60 events for an ADR rate equal to the background rate of 0.1. The number of events required for a background rate of 0.05 and an ADR rate equal to a 20% increase of the background rate was 900. Based on this study, it is recommended to use the dWSP-pWSP test combination for signal detection with a significance level of 0.004 when the same test is applied to all adverse events not depending on rates.