Reliable Test Method Research Articles

Accuracy of real-time PCR for the detection of paratuberculosis in actual samples: A systematic review and meta-analysis.

Paratuberculosis, an infectious and chronic ailment that affects ruminants, causes significant annual economic losses to the livestock industry. Early diagnosis and prompt culling are the primary measures for controlling this disease, highlighting the need for accurate and rapid diagnostic methods. This systematic review and meta-analysis aimed to evaluate the efficacy of quantitative PCR (qPCR) in the diagnosis of paratuberculosis. We searched for and selected articles from databases including PubMed, Web of Science, Elsevier ScienceDirect, Wiley-Blackwell, Springerlink, AGRICOLA, and CAB Abstracts, with VETQUADAS (VQ) employed to assess the quality of the literature. Meta-analysis and heterogeneity investigation were conducted using the "Meta4diag" package in "R" software, Meta-Disc 2.0, and Meta-Disc, while the Deeks' test was utilized to detect publication bias. The studies included in the systematic review displayed a moderate level of heterogeneity (I² = 48.6 %) with no significant publication bias (p = 0.998). The pooled sensitivity was determined to be 0.92 [95 % confidence interval [CI], 0.85-0.96], and the specificity was 0.85 [95 % CI, 0.77-0.91], with a summary receiver operating characteristic area under the curve (SROCAUC) of 0.95 [95 % CI, 0.91-0.98]. These findings indicate that the qPCR method has high diagnostic value for identifying paratuberculosis in animals. Subgroup analysis revealed satisfactory stability in these studies; however, the current single-target qPCR detection strategy still has limitations, as it fails to simultaneously ensure both sensitivity and specificity. Future developments should focus on multi-target detection strategies to provide more reliable qPCR testing methods for controlling paratuberculosis.

Pengaruh Penerapan Iso 9001 dan Kualitas Produk Pada Keputusan Pembelian

This study examines the effect of ISO 9001 implementation and product quality on Purchasing Decisions. This study uses a quantitative method with primary data through a survey to collect data. Respondents in this study were employees of PT Epson Indonesia, with the number of employees who were sampled was 30 employees. The sampling method used in the study was purposive sampling, while the data processing method used the Corrected Item to Total Correlation method for validity testing and the Cronbach's Alpha method for reliability testing. The results showed that from 15 question instruments related to the ISO 9001 variable, product quality, and Purchasing Decisions were declared valid with a significant percentage of 0.05 or 5% and were declared consistent/reliable with Cronbach's alpha of 0.938> 0.60.

Thesis Candidates' Expectations and Satisfaction with Thesis Supervisors' Customer Service Quality in the Upper East Region: An Expectancy Theory Perspective

Aim: The purpose of this study was to contribute to discussions aimed at creating a supportive academic experience for postgraduate students through quality customer service support systems. Methods: The study employed the expectancy theory as a guiding theoretical framework to investigate thesis candidates' expectations and satisfaction with supervisors' customer service quality in terms of thesis supervision in the Upper East region. The study adopted quantitative descriptive and inferential analytical methods to analyze the primary data, collected using a self-developed questionnaire instrument from 113 selected respondents using a purposive technique. To ensure reliability, the questionnaire was first piloted using 40 respondents. The piloted data were analyzed using Cronbach's reliability test method. The data produced reliability coefficients of .947, .974, and .957 for the constructs. Results: The study revealed that thesis candidates have moderate to high expectations for their supervisors' customer service quality in thesis supervision. A paired samples t-test analysis revealed a significant difference between postgraduate students' expectations and satisfaction regarding the supervisor's customer service quality in thesis supervision (t(112) = 2.635, p < 0.01). A simple linear regression analysis result also showed a significant positive relationship between satisfaction and the likelihood to pursue further studies (R square = 0.696, F (1, 111) = 253.988, p < 0.001). The R square value indicates that 69.6% of the variance in student's likelihood of pursuing a PhD program can be explained by their satisfaction with their supervisor's customer service. Recommendation: The study recommended that thesis supervisors should provide quality customer service in terms of their approachability, expertise, guidance/support, and responsive supervisory relationship.

The Influence of Cyber Security Knowledge, Cyber Security Awareness, and Behaviour Protection on Intention to Use Among Mobile Banking Users in Jakarta

Businesses and individuals, especially banks, must use risk assessment methods and preventive measures to protect mobile banking application users. Looking at these events, the researcher aims to see whether cyber security awareness, knowledge & behavior protection of users affect the intention to use mobile banking applications and whether these three variables are important for mobile banking users to understand in maintaining the security of transactions using mobile banking which will test the influence of these 3 variables on users' interest in continuing to use mobile banking even though users know the high risk if there is negligence in carrying out these 3 things and believing in the security of the mobile banking system in Indonesia. The population of this study is people who work in Jakarta. The respondents' answers were taken using Google Docs and distributed in general. The researcher obtained a total of 130 respondents. The data was processed using SPSS 27 with the analysis method of validity, reliability, and hypothesis test including the R2 test, F test, and T-test.

Review of the Hazards and Contraindications of Etomidate.

Etomidate, an ultrashort-acting non-barbiturate sedative derived from imidazole, exerts potent inhibitory effects on the central nervous system. It is commonly employed for the induction of intravenous general anaesthesia or assisted anaesthesia. Recently, etomidate has emerged as an alternative to narcotics and novel psychoactive substances, leading to an increasing trend of abuse. Chronic overdose of etomidate can result in irreversible brain damage and various mental disorders. Severe cases may manifest as mental disturbances, behavioural disorders, self-mutilation and even death. The toxicological mechanisms of etomidate remain poorly understood. Additionally, there is limited information on the clinical symptoms and histopathological changes associated with etomidate poisoning and standardized detection methods for etomidate in blood, urine and hair are lacking. Consequently, further research on toxicological pathology and the development of reliable testing methods is crucial. This study reviews the metabolism, distribution, adverse reactions, poisoning manifestations, toxicology mechanisms and testing methods of etomidate.

Fosfomycin-Overcoming Problematic In Vitro Susceptibility Testing and Tricky Result Interpretation: Comparison of Three Fosfomycin Susceptibility Testing Methods.

Background: Fosfomycin (FOS) is an older antimicrobial agent newly rediscovered as a possible treatment for infections with limited therapeutic options (e.g., Gram-negative bacteria with difficult-to-treat resistance, DTR), especially in intravenous form. However, for correct usage of FOS, it is necessary to have a reliable susceptibility testing method suitable for routine practice and robust interpretation criteria. Results: The results were interpreted according to 2023 interpretation criteria provided by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). DTR Gram-negatives were more likely to be resistant to FOS (45% in Enterobacterales and 20% in P. aeruginosa) than non-DTR (10% and 6.7%, resp.). All isolates of S. aureus were susceptible to FOS. In Gram-negatives, all agreement values were unacceptable. Etest® performed better in the DTR cohort (categorical agreement, CA, 80%) than in the non-DTR cohort (CA 45.7%). There were no very major errors (VREs) observed in P. aeruginosa. S. aureus had surprisingly low essential agreement (EA) rates (53% for MRSA and 47% for MSSA) for Etest®, but categorical agreement was 100%. Methods: A total of 130 bacterial isolates were tested and compared using the disc diffusion method (DD) and gradient strip method (Etest®) with the reference method (agar dilution, AD). The spectrum of isolates tested was as follows: 40 Enterobacterales (20 DTR vs. 20 non-DTR), 30 Pseudomonas aeruginosa (15 DTR vs. 15 non-DTR), and 60 Staphylococcus aureus (30 methicillin-susceptible, MSSA, vs. 30 methicillin-resistant, MRSA). Conclusions: Neither one of the tested methods was identified as a suitable alternative to AD. It would be beneficial to define more interpretation criteria, at least in some instances.

Exosomes: A Fluid Biopsy Source for Clinical Interventions of Noncommunicable Diseases Treatment: A Review

Introduction: The beginning of exosome biosynthesis is marked by the emergence of the initial endosomes through the inward splitting of the plasma cell membrane. This process is facilitated through the endosomal categorization complex essential for transport, which is also involved in the production of different extracellular vesicles. Exosomes are naturally occurring nanosized vesicles found in all bodily fluids and can be successfully extracted from preserved biological materials, while maintaining their structural integrity. Methods: The articles published recently in high-quality journals (Science Direct, Springer, Institute of Electrical and Electronics Engineers (IEEE), and Taylor & Francis) indexed in various indexing sources such as Scopus, Web of Science, PubMed, Google Scholar, and so on were collected using keywords such as fluid biopsy (FB) exosomes, endosomes, and noncommunicable diseases (NCDs) treatment, new biomarkers, and treatment. Discussion: In recent years, exosomes have emerged as an exciting option for “FB” that has demonstrated significant potential in the areas of noninvasive medical testing, predictions, as well as tracking responses to therapy for noncommunicable diseases. Nevertheless, specific constraints need to be addressed to expand the application of exosome-based FB as a widely accepted and reliable testing method in typical medical facilities. Conclusion: This review provides a comprehensive overview of our present understanding of exosomes to be an FB method for diagnosing, predicting outcomes, and tracking treatment responses in NCDs. It also discusses the main constraints, innovations in technology, as well as future possibilities of using this application in medical treatment.

WORK MOTIVATION OF LECTURERS AT CAN THO UNIVERSITY OF TECHNOLOGY

This study aims to analyze factors influencing the work motivation of lecturers at Can Tho University of Technology. The research was conducted based on opinions collected from 160 lecturers at this university. Reliability testing methods using Cronbach's Alpha coefficient, exploratory factor analysis (EFA), and multiple regression analysis were employed for analysis. The estimated results indicate that factors influencing the work motivation of university lecturers include Job characteristics, Working conditions, Salary, Bonuses, benefits, Training and promotion opportunities, and Relationships with superiors. Among these, relationship with superiors is identified as the strongest factor impacting the work motivation of lecturers.

Factors Influencing Measurement of Dynamic Elastic Modulus from Disk-Shaped Concrete Specimen

The decrease in dynamic elastic modulus is a primary indicator of quantitative damage in concrete. To quantitatively assess depth-by-depth damage within a concrete structure, cylindrical specimens obtained through coring can be cut into disk specimens to measure the dynamic elastic modulus of concrete at each depth. To minimize external damage during coring, it is essential to extract cylinders with the smallest possible diameter. In addition, for higher resolution in depth-based damage assessment, creating disk specimens with the smallest possible thickness is necessary. However, there is no information available in the literature on experimental limitation of smallest possible diameter and thickness for dynamic elastic modulus of disk-shaped specimens. This study evaluated whether the dynamic modulus measured from various sizes of concrete disk specimens provided sufficient reliability compared to reference values obtained from cylinders. Moreover, the study examined how the presence of coarse aggregate and variation in the water–cement ratio significantly influenced the dynamic modulus measurement. In addition, test results from impulse excitation technique (IET) and impact resonance (IR) were compared to find a more reliable test method for dynamic elastic modulus of disk specimen. The experimental findings revealed that as the thickness-to-radius ratio of the disk specimens decreased, measured data variation increased. Mortar specimens without coarse aggregates showed less variability compared to concrete specimens, and the variation in dynamic modulus measured by IR was lower than that measured by IET.

LABORATORY DETECTION OF COLISTIN-RESISTANT <i>ENTEROBACTERALES</i> IN TANDEM WITH ROUTINE ANTIBIOGRAM

Since the emergence and spread of carbapenemase-producing Enterobacterales, particularly those carrying metallo-β-lactamases with 16S rRNA methyltransferases for which newly introduced antibiotics are inactive, colistin is a last resort therapy for life-threatening extensively drug-resistant infections. This requires that laboratories use an accurate and reliable method for routine colistin susceptibility testing. The aim of this study was to evaluate the performance and applicability of a colistin screening medium for detection of colistin-resistant isolates simultaneously with routine susceptibility testing. It was evaluated with fifty colistin-resistant and the same number of colistin-susceptible comparator isolates. Our results showed that all colistin-resistant isolates grew on DiaPlate™ EMB Agar + Colistin medium within the standard antibiogram period. In contrast, no growth was observed among the colistin susceptible comparators. DiaPlate™ EMB Agar + Colistin is a screening medium that can detect colistin- resistant Enterobacterales isolates when pure bacterial cultures are tested. As this method for detecting colistin-resistant isolates uses the same inoculum as the Kirby-Bauer method, the screening test for colistin resistance can be conveniently performed on clinical isolates along with routine antimicrobial susceptibility testing.

Research on Silage Corn Forage Quality Grading Based on Hyperspectroscopy

Corn silage is the main feed in the diet of dairy cows and other ruminant livestock. Silage corn feed is very susceptible to spoilage and corruption due to the influence of aerobic secondary fermentation during the silage process. At present, silage quality testing of corn feed mainly relies on the combination of sensory evaluation and laboratory measurement. The sensory review method is difficult to achieve precision and objectivity, while the laboratory determination method has problems such as cumbersome testing procedures, time-consuming, high cost, and damage to samples. In this study, the external sensory quality grading model for different qualities of silage corn feed was established using hyperspectral data. To explore the feasibility of using hyperspectral data for external sensory quality grading of corn silage, a hyperspectral system was used to collect spectral data of 200 corn silage samples in the 380–1004 nm band, and the samples were classified into four grades: excellent, fair, medium, and spoiled according to the German Agricultural Association (DLG) standard for sensory evaluation of silage samples. Three algorithms were used to preprocess the fodder hyperspectral data, including multiplicative scatter correction (MSC), standard normal variate (SNV), and S–G convolutional smoothing. To reduce the redundancy of the spectral data, variable combination population analysis (VCPA) and competitive adaptive reweighted sampling (CARS) were used for feature wavelength selection, and linear discriminant analysis (LDA) algorithm was used for data dimensionality reduction, constructing random forest classification (RFC), convolutional neural networks (CNN) and support vector machines (SVM) models. The best classification model was derived based on the comparison of the model results. The results show that SNV-LDA-SVM is the optimal algorithm combination, where the accuracy of the calibration set is 99.375% and the accuracy of the prediction set is 100%. In summary, combined with hyperspectral technology, the constructed model can realize the accurate discrimination of the external sensory quality of silage corn feed, which provides a reliable and effective new non-destructive testing method for silage corn feed quality detection.

Novel dissolution methods for drug release testing of Long-Acting injectables

Long-acting parenteral drug products are a popular choice for therapeutic areas requiring long term treatment. These products range from dispersed systems such as drug suspensions and polymeric microspheres to in situ forming polymeric implants. The lack of reliable drug release testing methods for these drug products not only impedes the development of new drug products but also affects generic drug development. Current release methods suffer from a range of problems such as high variability, poor reproducibility, poor discriminatory ability, lack of depot-like structure formation (that could mimic the in vivo situation). Moreover, shorter duration (less than a week) of release renders them unsuitable for in vitro-in vivo correlations (IVIVCs). To overcome these issues, novel adapters were developed for both USP-type-II & IV apparatus. These adapters were validated and assessed using the long-acting injectable (LAI) suspension drug product Depo Provera 150® as well as its Q1/Q2 equivalents. For USP-type-IV apparatus, two open adapter designs (conical and ellipsoidal shaped cavity with volume capacities of 50 µl and 1 ml, respectively) were developed. A closed conical adapter design with a volume capacity of 0.05 ml was developed for USP apparatus type-II. All three novel adapter designs effectively retained the suspensions, achieved release durations of 3–6 weeks with good reproducibility, minimal variability (RSD≤5%) and had good discriminatory ability. Based on this, the adapter-based dissolution methods were deemed suitable for IVIVC development of long-acting injectables. A successful Level A IVIVC was developed for Depo SubQ Provera 104® and its Q1Q2 equivalents using USP apparatus type IV with a conical adapter design. The closed adapter design for apparatus type-II was also investigated for suitability with risperidone in situ forming implants. The adapter was able to securely retain and maintain the shape of the in situ forming implants and resulted in release profiles of up to one month with good discriminatory ability and low standard error (RSD≤5%). These novel adapters hold promise of wide use for in vitro release testing of different long-acting parenteral drug products.

Multiprobe Amplification (MPA) with Melting Curve Analysis: A Highly Stable and Cost-Effective Platform for the Simultaneous Detection of Eight Potential Bacterial Bioterrorism Agents in Complex Samples.

We aimed to develop an efficient detection platform that can identify a larger number of suspicious samples in a single test, saving time, manpower, and material costs, and providing vital support to the public health system in coping with the current challenging and dynamic bioterrorism threat landscape, particularly in regions of turmoil and conflict. We have successfully developed a high-throughput, multitarget fluorescent array detection platform by effectively combining integrating multiprobe amplification (MPA) with melting curve analysis. Specifically, we have established reliable laboratory testing methods for eight highly pathogenic bacteria, including Bacillus anthracis, Yersinia pestis, Brucella spp., Burkholderia pseudomallei, Francisella tularensis, Vibrio cholerae, Salmonella typhi, and Staphylococcus aureus. Our method achieves sensitive and specific simultaneous detection of eight target bacteria in one well by optimizing the reaction conditions of MPA. In the assessment of 192 simulated environmental samples, both positive and negative coincidence rates were 100.00%. Among 48 simulated clinical samples, the positive coincidence rate reached 97.73%, while maintaining a perfect negative coincidence rate of 100.00%. Moreover, the detection platform holds immense potential for attaining a more comprehensive bioterrorism screening, and its high cost-effectiveness enables the provision of diverse and adaptable diagnostic methods for public health quarantine in underdeveloped countries and regions.

New Computational Methods for Enhancing Reliability Testing of Interconnects in 3D ICs: Advanced Algorithms, Optimization Techniques, and Real-World Applications

New Computational Methods for Enhancing Reliability Testing of Interconnects in 3D ICs: Advanced Algorithms, Optimization Techniques, and Real-World Applications

Determinan Factor On Behaviour Auditor Disfunction

Purpose: This research was conducted on Public Accountants in Indonesia. This study aims to investigate how Time Budget Pressure, Locus Of Control, Independence and Gender are related to Dysfunctional Behavior of Auditors in Indonesia Methodology/approach: Primary data collection method with questionnaire dissemination. Instrument trials use validity and reliability test methods. Test the data using model analysis, normality test, and model test. Test the hypothesis using SEM analysis. Findings: Based on the results of the study shows that there is a positive influence of Time Budget Pressure and Locus Of Control on the Auditor's Dysfunctional Behavior. However, there is no influence between independence and gender on the auditor's dysfunctional behavior. Practical implications: So that IAPI in audit training emphasizes more on case studies of timely completion of work, efficient allocation of audit time and evaluating appropriate audit evidence. Originality/value: There have been many studies in developed countries that discuss time budget pressure and locus of control for dysfunctional auditors, but there are still few studies in developing countries that discuss time budget pressure, locus of control, independence and gender on dysfunctional auditors.

WORK-LIFE BALANCE (WLB) OF TEACHERS IN PANDEMIC

Work-life balance has been a global issue for decades. During this pandemic covid-19 lock-down which compelled everyone to work from home (WFH) it became a challenge for all professionals to make a balance between work and life. In this paper researcher focused on WLB of teacher fraternity in lock-down in order to find out the impact of lock-down on teacher’s personal life as well as professional life. The researcher also tends to study the advantages and disadvantages of WFH and changing habits of people in lock-down. The researcher has used the Cronbach Alfa method for reliability testing while frequency, percentage, mean, and standard deviation methods for descriptive analysis. Hypotheses are tested by using one sample t-test. It is found that most of the teachers experience a positive impact on their mental well-being, physical well-being & personal life also in WFH during lock-down. But in the case of professional life and changing habits, it is negatively impacting most samples. Lock-down reduced various expenses significantly in case of individual budgets.

Design of a continuously repeated impact method with constant amplitude based on Hopkinson bar: Principle and impact fatigue life testing

The lack of reliable testing methods and standards hinders systematic research on the impact fatigue performance of materials. The aim of developing an impact fatigue test method is to generate repeated impact loads with a constant amplitude, which is difficult to achieve using various existing impact test devices. This study investigated the principles of cyclic loading-resetting and constant-amplitude loading based on the split Hopkinson pressure bar (SHPB) system, established a novel impact fatigue test device, and verified the developed method by testing the impact fatigue life of a Ti-6Al-4V alloy. Electromagnetic valves, laser sensors, and a vacuum pump were used in the developed device to launch and reset the striker bar; a servo motor and laser sensors were used to reset the loading bars and specimen, and the entire system was controlled by a programmable controller to achieve continuously repeated loading. To achieve constant-amplitude loading, the conditions required to ensure that the specimen moves away from the incident bar before the returning stress wave reloads the specimen was derived. It was found that a constant-amplitude repeated impact on the specimen could only be achieved through the precise design of the geometric configuration and material of the loading bars. This method is considerably simpler than various existing methods based on energy absorption and is more applicable to impact fatigue tests. The verification tests showed that the highest loading frequency of the device was 0.5 Hz, the loading rate exceeded 105 kN/s, and the amplitude error of the repeated impact loads did not exceed 2.45 %. Under loads with the same amplitude, the impact fatigue life of a Ti-6Al-4V alloy was considerably shorter than the non-impact (low strain rate) fatigue life, which indicates the necessity of investigating the strain rate effect on the fatigue performance of materials.

Study on Rapid Non-Destructive Detection Method of Corn Freshness Based on Hyperspectral Imaging Technology.

(1) Background: To achieve the rapid, non-destructive detection of corn freshness and staleness for better use in the storage, processing and utilization of corn. (2) Methods: In this study, three varieties of corn were subjected to accelerated aging treatment to study the trend in fatty acid values of corn. The study focused on the use of hyperspectral imaging technology to collect information from corn samples with different aging levels. Spectral data were preprocessed by a convolutional smoothing derivative method (SG, SG1, SG2), derivative method (D1, D2), multiple scattering correction (MSC), and standard normal transform (SNV); the characteristic wavelengths were extracted by the competitive adaptive reweighting method (CARS) and successive projection algorithm (SPA); a neural network (BP) and random forest (RF) were utilized to establish a prediction model for the quantification of fatty acid values of corn. And, the distribution of fatty acid values was visualized based on fatty acid values under the corresponding optimal prediction model. (3) Results: With the prolongation of the aging time, all three varieties of corn showed an overall increasing trend. The fatty acid value of corn can be used as the most important index for characterizing the degree of aging of corn. SG2-SPA-RF was the quantitative prediction model for optimal fatty acid values of corn. The model extracted 31 wavelengths, only 12.11% of the total number of wavelengths, where the coefficient of determination RP2 of the test set was 0.9655 and the root mean square error (RMSE) was 3.6255. (4) Conclusions: This study can provide a reliable and effective new method for the rapid non-destructive testing of corn freshness.

ANALISIS USABILITY SISTEM MANAJEMEN PEMBELAJARAN DI WASKITA UNIVERSITAS AMIKOM: PENDEKATAN DENGAN SYSTEM USABILITY SCALE

This research was conducted at Amikom University Yogyakarta, a university that responded adaptively to the pandemic by developing the Waskita Learning Management System (LMS). Waskita LMS functions as a supporting platform for teaching and learning activities, facilitating the exchange of lecture materials, assignment collection, and quizzes between lecturers and students. Usability analysis was carried out using the System Usability Scale (SUS) method, a simple and reliable user testing method. The analysis results show that LMS Waskita received an average SUS score of 54.2, falling into the Not Acceptable category, indicating the need for improvement. Apart from calculating the SUS, an analysis of respondents' suggestions was also carried out to strengthen the evaluation results. This research provides valuable insights for developing and improving the quality of the Waskita LMS to improve user experience and usability.

Solving inverse problems in magnetic field leakage sensor array inspection of petroleum tank floor

The MFL method is a qualitative inspection tool and is a reliable, fast, and economical nondestructive testing method for tank floors. In this paper, before presenting the defect reconstruction procedure, we studied the effect of defect parameters on the magnetic field leakage measured by a single Hall sensor. As predicted, the study of each parameter has demonstrated that any variation in the geometrical parameters of the studied defect induce a significant influence on the MFL signal amplitude and distribution; for this reason, all the defect parameters must be determined precisely and prudently. After that, we have studied the performance of defect shape reconstruction from MFL array sensor imaging and depth estimation while using an iterative inversion method. Indeed, the first stage consists of determining the defect width and length from magnetic flux leakage mapping reconstructed from the recorded signals of the micro-integrated magnetic sensors. As a second step, after coupling Comsol and Matlab software, the defect depth is obtained by coupling the 3D finite elements method and a fast iterative algorithm recently developed. Consequently, the defect shape and size are obtained after a few iterations with a relative error of less than 2%; which makes this method very appropriate for real-time defect reconstruction and quantification. Furthermore, this method of defect reconstruction and seizing can be extended for irregular shape such as cracks and corrosion. In fact, this can be done while subdividing the affected area of non-constant depth into elementary zones of a constant depths. Then, while modifying the previous algorithm, we determine the corresponding depth of each zone.