Exhaustive Measurements Research Articles

Resolving Relationships in Mentzelia Section Bartonia (Loasaceae) in the Face of Cytonuclear Discordance

Abstract— Phylogenetic studies conducted with two nuclear ribosomal markers created the first phylogenetic framework in which to understand evolutionary relationships in Mentzelia section Bartonia (Loasaceae), but low molecular variation resulted in several large polytomies and an incomplete understanding of species relationships. We applied a genome skimming approach to determine whether additional genetic variation generated from high-throughput sequencing could resolve relationships in one of the largest polytomies in the section. Among the 20 species sequenced, five species that have pinnatisect leaf morphology were previously hypothesized to be monophyletic and we tested whether additional data would resolve the group as monophyletic. For the chloroplast genome, reads were assembled with de novo and reference guided approaches, whereas reference guided approaches were taken for the nuclear ribosomal cistron region and a single anonymous nuclear locus. Significant discordance was identified among all three gene trees. Exhaustive measures were taken to ensure phylogenetic and assembly-based errors were not responsible for the observed discordance among gene trees. We attribute incongruence to a low phylogenetic signal to noise ratio that is likely caused by the clade radiating recently and rapidly and perhaps unique evolutionary histories among genomes. Despite incongruence, several well-supported relationships emerged across data sets, and although two out of three gene trees did not recover a monophyletic pinnatisect group, all hypothesis tests for a monophyletic pinnatisect group among gene trees failed to reject monophyly of the group.

Comprehensive analysis on the effect of lube oil on particle emissions through gas exhaust measurement and chemical characterization of condensed exhaust from a DI SI engine fueled with hydrogen. Part 2: Effect of operating conditions

The need to cope with carbon dioxide abatement has prompted the development of innovative technologies for sustainable mobility. Meanwhile, these technologies consolidate, an important role will be played by internal combustion engines fed with non-fossil fuels such as hydrogen. Theoretically, the combustion of hydrogen should not produce carbon-based emissions. Nevertheless, particles can be found in the exhaust of hydrogen-fueled engines because of the lubricating oil. In this study, a thorough examination of the impact of the engine lubricant on the mechanisms leading to the formation of the particles and the high levels of hazardous pollutants was performed in this study. Experiments were carried out on a direct injection spark ignition engine fueled with hydrogen. The analysis was conducted at 2000 and 3000 rpm both low and full load. Number and size particle distribution were determined by means of on-line measurement on the diluted exhaust. Off-line chemical characterization through analytic techniques was realized on the condensed exhaust and on the particles collected on a filter. Experimental results pointed out that the extent of the particle size varies according to the engine speed and load, evidencing the different role of the oil ascribable to the environmental conditions. It was found that aromatic molecules and nanoparticles are present in the exhausts at all the investigated operating conditions, whereas soot aggregates are formed only at high engine speed.

High flow nasal cannula versus noninvasive ventilation in the treatment of acute hypercapnic respiratory failure: A systematic review and meta-analysis.

Chronic obstructive pulmonary disease can lead to acute hypercapnic respiratory failure (AHRF), often treated using noninvasive ventilation (NIV). Emerging research suggests the potential utility of high flow nasal cannula (HFNC) for AHRF. This systematic review and meta-analysis aimed to determine the effect of HFNC versus NIV on AHRF management. A search of electronic databases (CINAHL, MEDLINE, and Academic Search Complete), web sources, and trial registries was last conducted on 9 February 2023. Quality and risk of bias assessments were conducted. Meta-analyses were used to synthesise data. Seven randomised controlled trials were included. No statistically significant differences between HFNC and NIV were found within the following outcomes of interest: (i) correction of pCO2: standardised mean difference (SMD) = -0.16, 95% confidence interval (CI) (-0.34 to 0.02), p = 0.08; (ii) correction of pH: SMD = -0.05, 95% CI (-0.25 to 0.14), p = 0.59; (iii) correction of pO2: SMD = -0.15, 95% CI (-0.40 to 0.09), p = 0.22; (iv) intubation rates: risk ratio (RR) = 0.87, 95% CI (0.41 to 1.82), p = 0.71; (v) mortality rates: RR = 0.85, 95% CI (0.47 to 1.56), p = 0.61; and (vi) treatment switch: RR = 1.30, 95% CI (0.43 to 3.94), p = 0.64. More controlled trials with large sample sizes are required to investigate the management of AHRF of various aetiologies. HFNC may be used as a final exhaustive measure for COPD-related AHRF where NIV is not tolerated, and when it is not clinically indicated to extend to endotracheal intubation.

Intra-urban migration and perceptions of neighborhood cohesion in urban China: The case of Guangzhou

Although the consequences of intra-urban migration have received wide attention, few studies have elucidated whether and how processes of intra-urban migration are associated with perceptions of neighborhood cohesion. This paper tries to extend the literature on neighborhood cohesion by explicitly incorporating the experience of past intra-urban residential moves into multilevel analysis based on a large-scale survey undertaken in Guangzhou. The results reveal that features of intra-urban migration (e.g., tenure shift, change in housing type and frequencies of intra-urban residential movement) have discernible effects on four different dimensions of neighborhood cohesion: Social solidarity, neighborly acquaintance, social trust and informal social control. The findings not only contribute to a more refined understanding of intra-urban migration influences, but also suggest considering a more exhaustive measure of residential history in future explanations of neighborhood cohesion.

Novel Method for Improving Motion Accuracy of a Large-Scale Industrial Robot to Perform Offline Teaching Based on Gaussian Process Regression

Industrial robots that can respond to the current needs for variable-type and variable-volume production and that can play a variety of roles such as processing and transporting with a single robot to reduce time and cost. If realized, these robots will help save space in factories and increase production efficiency. However, this requires high positioning accuracy of the robot. In this study, we analyze the motion accuracy of industrial robots and their compensation method to construct this system. Here, we use a laser tracker to measure the coordinates of the hand tip of the robot when the robot is stationary. Subsequently, the error amount in an arbitrary posture is predicted using a Gaussian process. Furthermore, Bayesian optimization is used to efficiently search for points where the positioning error norm is likely to be large, which is then compensated for by a feedback method. This method successfully reduced the time cost of the experiment to approximately one-tenth of that required in the previous study and achieved a correction of approximately 66 %. However, because this method alone does not perform an exhaustive measurement, it is unclear whether all the points predicted to have small errors are so small that they do not require correction. Therefore, future studies, we will aim to verify this issue by considering the time efficiency.

Randomized trial of personalized psychological feedback from a longitudinal online survey and simultaneous evaluation of randomized stepped wedge availability of in-person peer support for hospital staff during the COVID-19 pandemic

ObjectiveWe tested if automated Personalized Self-Awareness Feedback (PSAF) from an online survey or in-person Peer Resilience Champion support (PRC) reduced emotional exhaustion among hospital workers during the COVID-19 pandemic. MethodAmong a single cohort of participating staff from one hospital organization, each intervention was evaluated against a control condition with repeated measures of emotional exhaustion at quarterly intervals for 18 months. PSAF was tested in a randomized controlled trial compared to a no-feedback condition. PRC was tested in a group-randomized stepped-wedge design, comparing individual-level emotional exhaustion before and after availability of the intervention. Main and interactive effects on emotional exhaustion were tested in a linear mixed model. ResultsAmong 538 staff, there was a small but significant beneficial effect of PSAF over time (p = .01); the difference at individual timepoints was only significant at timepoint three (month six). The effect of PRC over time was non-significant with a trend in the opposite direction to a treatment effect (p = .06). ConclusionsIn a longitudinal assessment, automated feedback about psychological characteristics buffered emotional exhaustion significantly at six months, whereas in-person peer support did not. Providing automated feedback is not resource-intensive and merits further investigation as a method of support.

Soiling model for spectral reflectance of solar mirrors

In concentrating solar power plants, mirrors are used to redirect solar radiation onto a receiver. The optical yield of a plant is related to the mean value of the near-specular reflectance in the range of interest of incidence and acceptance angles for that plant. To avoid the need for an exhaustive measurement of the solar mirror at various incidence and acceptance angles, a predictive method based on the Equivalent Model Algorithm for Solar Mirrors was recently proposed. Whilst developed for clean surfaces, unfortunately that model is inaccurate for soiled solar mirrors. In this paper, an additional model to describe the spectral reflectance loss caused by soiling of solar mirrors is presented and successfully tested on a set of artificially and naturally-soiled specimens. The model is based on absorption, scattering and diffraction. Its parameters are obtained by best-fitting a set of experimental hemispherical and near-specular reflectance spectra, both in soiled and cleaned state. The best-fit software developed is now published as open source software, providing access also to non-specialized users. The model also allows to correlate simple handheld reflectometer readings used in the solar field (with typically limited spectral and acceptance angle information) to the most meaningful parameter determining the plant yield: the solar-weighted near-specular spectral reflectance of the soiled reflector. Such correlations are specific for the plant, the kind of local dust and the chosen portable reflectometer.

Employee human resource management values: validation of a new concept and scale.

Although human resource management (HRM) practices all seek to support and improve organizational functioning, the value ascribed to various HRM practices differs greatly among employees. Drawing on an exhaustive measure of HRM practices, this study proposed a new conceptualization and measure of HRM values, the HRM Values Scale (HRM-VS). To examine the psychometric properties of scores obtained on this new measure, we rely on a sample of 979 employees occupying a variety of jobs within various private and public organizations. Through the comparison of confirmatory factor analysis (CFA) and exploratory structural equation modeling (ESEM) solutions, our results supported a nine-factor structure of participants' responses to the HRM-VS and the measurement invariance of this solution across male and female employees. Specifically, they support that the HRM-VS items adequately capture core HRM values underlying independent HRM practices. Criterion-related validity was evidenced with respect to employees' ratings of intrinsic and extrinsic job satisfaction. The HRM-VS appears to represent a promising tool for research and intervention seeking to account for individual differences in the relative importance of various HRM practices, in order to devise more effective HRM systems. This new concise but complete measure could help better guide organizations in tailoring their strategic HRM. This study introduces HRM values as a valid concept that characterizes what employees desire or consider to be important in relation to HRM practices.

Comprehensive analysis on the effect of lube oil on particle emissions through gas exhaust measurement and chemical characterization of condensed exhaust from a DI SI engine fueled with hydrogen

This research study aims to investigate the causes of the particles emitted by a spark ignition engine fueled with hydrogen. The experiments were carried out on a single cylinder 250 cm3 direct injection spark ignition engine. Two operating conditions at 2000 rpm both full and low load, representative of typical urban conditions, were investigated. A physical characterization of the particles, size and number, was performed through an Engine Exhaust Particle Sizer coupled to a single diluter. Chemical characterization was carried out on the condensed exhaust. The simultaneous analysis of the physical properties and their chemical characterization allows to point out not only the role of the oil on the particle emissions but also to give an important information on its state/composition, if it was unburned and oxidized. Particles were detected with conventional spectrometer at low load while at high load the noise signal ratio is too high to distinguish the presence of particles. More detailed chemical techniques highlighted the presence of PAH, alkyl-PAHs, oxy-PAHs and unburned hydrocarbon in the exhaust due to the mineral oil.

Experimental investigation of the combustion instability behaviors and NOx emissions in an ammonia/methane fueled low eddy premixed burner

In this study, experimental analyzes were carried out to examine the combustion instability properties of methane-ammonia mixed fuels for a low eddy and premix burner. The aim of this study is to determine the effect of ammonia addition on combustion instability with different compelling acoustic frequencies, dynamic pressure amplitude, and light emission intensity. In addition, the effects of ammonia addition to methane fuel gas on temperature and emissions were also investigated. Pure methane and three different methane-ammonia mixtures as fuel at 0.7 equivalents and with three different acoustics have been used for analysis. The burner power was determined as 5 kW and the excitation frequencies of the combustion chamber were determined as 95, 160, and 300 Hz. As the ammonia addition increased, there was an increase in the flame instability values up to 30% NH3, especially at the 95 Hz frequency, where the highest distortion effect occurred. It was observed that there was no significant change in the combustion performance with the addition of ammonia to methane fuel. The predicted NOX emission levels were found to increase significantly due to nitrogen bound to ammonia. However, it is seen that the NOx emission levels in the exhaust measurements are not high.

Long-term associations of psychosocial working conditions with depressive symptoms and work-related emotional exhaustion: comparing effects in a 5-year prospective study of 1949 workers in Germany.

To test the hypothesis that psychosocial working conditions are more strongly associated with subsequent work-related emotional exhaustion (core component of burnout) than with depressive symptoms at follow-up. A 5-year cohort study (2011/2012-2017), based on a random sample of persons in employment subject to payment of social contributions aged 31-60years (Study on Mental Health at Work; S-MGA; N = 1949), included self-reported measures of organisational demands (organisational layoffs and restructuring), task-level demands (work pace and amount of work) and job resources (influence at work, possibilities for development, control over working time, role clarity), all taken from the COPSOQ, except the organisational demands that were single-item measures. Work-related emotional exhaustion and depressive symptoms were measured with the Oldenburg Burnout Inventory and the Patient Health Questionnaire-9, respectively. Cochrane Q tests revealed stronger associations between psychosocial working conditions and work-related emotional exhaustion only for the amount of work (p = 0.013) and control over working time (p = 0.027). No differences were observed for the Demands and Resources Indexes, capturing overall exposure to psychosocial working conditions. The same differences were observed in a subsample including only participants who remained at the same employer from baseline to follow-up, although more psychosocial working conditions were associated with work-related emotional exhaustion than with depressive symptoms. Supplementary analyses employing dichotomous measures of work-related emotional exhaustion and depressive symptoms confirmed these results. Overall, the findings provide limited evidence supporting the hypothesis that psychosocial working conditions are more strongly associated with work-related emotional exhaustion than with depressive symptoms.

Dyadic effects of work overcommitment on depression in dual-earner couples: based on the actor–partner interdependence model

ABSTRACT In this study, we aimed to examine the actor and partner effects of overcommitment on depression in dual-earner couples and the potential mediating role of emotional exhaustion at the actor and partner levels. With a cross-sectional design, 172 dual-earner couples in Chongqing, China, completed the measures of overcommitment, emotional exhaustion, and depression. The results showed that (a) overcommitment has a significant actor effect on depression for the husband and wife, and there were gender differences in the partner effects; that is, a wife’s overcommitment has a significant partner effect on the husband’s depression, while a husband’s partner effect was not significant; (b) emotional exhaustion mediated the effects of overcommitment on depression for both husbands and wives at the actor level, while at the partner level, only a wife’s exhaustion mediated the partner effect of a wife’s overcommitment on a husband’s depression. Focusing on couples’ interdependence, these results enriched the understanding of the relationship between overcommitment and depression within dual-earner couples.

Study on ultrasonic attenuation characteristics in air-droplet two-phase flow

The wetness of exhaust steam in nuclear power plant steam turbine is an important index to evaluate the safety and economy of nuclear power plant and the ultrasonic attenuation method has the advantages of quick response and non-contact in the steam wetness measurement of nuclear power plant steam turbine. The saturated steam-droplet medium and the air-droplet medium have many similar thermal fluid characteristics, in order to simplify the experiment, the air-droplet two-phase flow is used to simulate the wet steam discharged from steam turbine of nuclear power plant, and the ultrasonic attenuation coefficient in the air-droplet two-phase flow is measured. The correlation between wetness and ultrasonic attenuation coefficient was studied by calibrating the wetness of the air-droplet two-phase flow and measuring the ultrasonic attenuation coefficient under different wetness conditions. Meanwhile, the static characteristics of ultrasonic transducer and the influence of flow velocity on attenuation coefficient are studied experimentally. According to the results of experiment and numerical calculation, the ultrasonic attenuation coefficient is very sensitive to the change of wetness. The ultrasonic attenuation coefficient and wetness has a good linear relationship in the wetness range (0–16%), the ultrasonic attenuation method is appropriate for the wetness measurement of turbine steam exhaust and has high precision when the droplet size is stable.

Inherently Charged Particle (ICP) Sensor Design

Ambient particles from natural and anthropogenic sources are a major cause of premature deaths globally. While there are many instruments suitable for scientific measurements of aerosols, better methods for long-term monitoring purposes are still needed, especially low-maintenance, affordable solutions for ultrafine particles. In this article, we present a new sensor design and prototype, the inherently charged particle (ICP) sensor, which uses the preexisting electrical charge of particles to measure particle concentration, instead of employing a charging mechanism, as is typical for instruments based on electrical detection. When the ICP-sensor is employed in conjunction with another instrument, information on the particle charge state can also be derived. We present the results of a laboratory characterization as well as two measurements in suggested applications: 1) engine exhaust measurements and 2) ambient measurements in a traffic environment, where we compare the sensor response to three particle concentration metrics: 1) number; 2) surface area; and 3) mass. The sensor proved suitable for both applications, the signal correlated best with number concentration in the engine emission measurements and with particle surface area in the ambient measurements. The measured charge concentrations were well-correlated ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}^{\,2} &gt;0.8$ </tex-math></inline-formula> ) with theoretical values calculated from the number size distribution assuming an equilibrium charge distribution.

Emotional Exhaustion and Turnover Intentions among Counselors in Rural Substance Use Disorder Treatment Programs

Counselor turnover is a serious problem for substance use disorder (SUD) treatment programs, especially in rural areas. This study examined the relationship between workload, workplace environment, and emotional exhaustion on turnover intentions among SUD treatment counselors in rural Pennsylvania. An online, anonymous survey was administered to rural SUD treatment counselors in Pennsylvania between October and December 2020. Completed surveys from 206 counselors were used for analysis. Variables included multi-dimensional measures of emotional exhaustion, intention to quit, workload, and workplace environment. Results showed age, perceptions of distributive justice, and management communication to be inversely related to emotional exhaustion and intention to quit. A subsequent analysis showed that the direct effects of these variables on intention to quit were reduced with the inclusion of emotional exhaustion in modeling, suggesting a potential mediation effect. Findings indicated that higher levels of emotional exhaustion were directly related to a greater intention to quit. A statistically significant indirect relationship was also found for distributive justice on intention to quit through emotional exhaustion, indicating a significant mediating effect. While counseling is a stressful occupation with high potential for burnout, these results show that organizations can adopt practices that help lower emotional exhaustion and turnover intentions for their counselors which could improve retention in the SUD treatment field. This is especially important for rural areas, where there is a high demand for SUD services and not enough treatment workers to meet that demand.

Burnout among HIV care providers: contextual understanding and measurements

Burnout among healthcare workers is a challenge for the availability and quality of healthcare services in many countries. Overall, burnout has far-reaching implications on doctors, patients, and the healthcare system. For example, emotionally and physically exhausted workers become less attentive and make mistakes more often. Moreover, contextual features of the healthcare system and the organizational culture of healthcare institutions can contribute to burnout prevention and vice versa. Burnout among healthcare workers also increases the risk of alcohol misuse, sleep disorders, fast food consumption, and the occurrence of obesity.Considering the shortage of standardized tools to measure burnout among medical workers, we aimed to adapt to the Ukrainian context one of the research tools: Maslach Burnout Inventory for Medical Personnel (MBI-HSS (MP)). The MBI-HSS (MP) addresses three scales: emotional exhaustion (EE) measures feelings of being emotionally overextended and exhausted by one’s work; depersonalization (DP) measures an unfeeling and impersonal response toward patients; personal accomplishment (PA) measures feelings of competence and achievement in one’s work.From November 2020 – April 2021 we conducted semi-structured interviews and questionnaires among HIV care providers (N = 117). The result revealed that 83.7 % of respondents had high emotional exhaustion, and 58.5 % had high depersonalization. But the dimension of personal achievement level was not indicative of burnout in this component: 45.5 % had a high level of personal achievement. Pre-test and piloting of the Ukrainian version of the Maslach Burnout Inventory for Medical Personnel (MBI-HSS (MP)) show the validity of this instrument. In addition, it was found that relationships with colleagues and the management of the healthcare institution were associated with higher rates of burnout among healthcare workers.

When power hurts: An explorative study on the relationship between toxic leadership, emotional exhaustion, turnover intention and job satisfaction

The present study is aimed to two related objectives: 1) to make a systematic review of the relationship between toxic leadership, burnout and turnover intentions in the workplace 2) to use this knowledge to investigate if and to what extent a toxic leadership style might negatively impact workers' burnout and turnover intentions. This second objective was pursuedconducting a survey focused on a convenience sample of 156 employees (48% males and 50% females), working in small and medium enterprises across Italy.&#x0D; The structured questionnaire adopted is composed of validated measures of emotional exhaustion (Sirigatti et al. 1988 ), toxic leadership (Schmidt, 2008), turnover intention (Mobley et al., 1978) and job satisfaction (Wanous et al., 1997). Results showed that all dimensions of burnout and turnover intentions were positively related to toxic leadership. Limitations of the study as well as practical implications for research and practice in HRM are discussed.

Evaluation of the distribution of spray deposits within a vine canopy from measurements on artificial targets and real leaves

Understanding the distribution of intercepted spray deposits is important for the study of the dose-response relationship of spraying a targeted pathogen and for the optimisation of the spraying process. However, carrying out exhaustive measurements of canopy spray deposits is difficult, particularly in production situations. This new experimental method for use in commercial vineyards was based on the installation of artificial targets (PVC collectors) within the canopy. To evaluate the quality of this experimental method for estimating the statistical distribution of deposition it was compared to an intensive manual method of foliar deposition measurements on real leaves. Intercepted deposition data on the real leaves and artificial targets were collected in a regular grid pattern within 12 non-contiguous vegetation sections. The results showed that although the means were similar, the variance in deposition appeared to differ between the distributions on artificial targets and real foliage, with CV values of between 37.4-52.7 % and 69.4-80.5 % respectively. Therefore, any central statistics must be supplemented with a statistical distribution analysis to account for the dispersion of deposition values within the vegetation. The results from comparisons between the cumulative distributions of intercepted deposition on the real leaves and on the PVC collector sections showed that the deposition estimates averaged over three-vine sections gave relevant, repeatable estimates for both approaches. The results also showed that for low deposition values, the experimental method led to a correct estimation of deposition on real leaves. However, above 230 ng dm² per 1 g/ha, the experimental method underestimated the deposition on real leaves by 13.6 %. Using these methodological results, it may be possible to develop models capable of predicting the distribution of deposition within the plant canopy. It would thereby be possible to develop an approach for variable-rate sprayer control that takes into account the phytosanitary risk and the site-specific variable structure of the vegetation during the season.

Measurements from inside a Thunderstorm Driven by Wildfire: The 2019 FIREX-AQ Field Experiment

Abstract The 2019 Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) field experiment obtained a diverse set of in situ and remotely sensed measurements before and during a pyrocumulonimbus (pyroCb) event over the Williams Flats fire in Washington State. This unique dataset confirms that pyroCb activity is an efficient vertical smoke transport pathway into the upper troposphere and lower stratosphere (UTLS). The magnitude of smoke plumes observed in the UTLS has increased significantly in recent years, following unprecedented wildfire and pyroCb activity observed worldwide. The FIREX-AQ pyroCb dataset is therefore extremely relevant to a broad community, providing the first measurements of fresh smoke exhaust in the upper troposphere, including from within active pyroCb cloud tops. High-resolution remote sensing reveals that three plume cores linked to localized fire fronts, burning primarily in dense forest fuels, contributed to four total pyroCb “pulses.” Rapid changes in fire geometry and spatial extent dramatically influenced the magnitude, behavior, and duration of pyroCb activity. Cloud probe measurements and weather radar identify the presence of large ice particles within the pyroCb and hydrometers below cloud base, indicating precipitation development. The resulting feedbacks suggest that vertical smoke transport efficiency was reduced slightly when compared with intense pyroCb events reaching the lower stratosphere. Physical and optical aerosol property measurements in pyroCb exhaust are compared with previous assumptions. A large suite of aerosol and gas-phase chemistry measurements sets a foundation for future studies aimed at understanding the composition of smoke plumes lifted by pyroconvection into the UTLS and their role in the climate system.

Airborne monitoring of compliance to NOx emission regulations from ocean-going vessels in the Belgian North Sea

Along the worldwide tightening of standards for sulphur emission from ocean going vessels (OGVs) come actions that are also being taken to reduce nitrogen emission. Particularly, as a milestone in this regard, on January 1st, 2021 the NOx Emission Control Area (NECA) for the North Sea and Baltic Sea came into effect. In response to the newly established NECA, the sniffer sensor system on the Belgian coastguard aircraft was modified and extended with a NOx sensor. Moreover, a methodology was developed to evaluate OGV compliance to the NOx emission limits through in situ measurements of the plume exhaust. The quality and uncertainty of the measurements demonstrate that it is likely to achieve an effective compliance monitoring of the NOx emission standards on the sea. Those emission standards are further divided into four tiers depending on the keel laying date. As has been proved by the results, NOx emissions for Tier II OGVs, contrary to what might be expected, are on average higher than those for Tier I OGVs. What is even more problematic, Tier II OGVs have also more often been found to be non-compliant than Tier I OGVs.