Direct Drivers Research Articles

Self-Balanced Clamp-Double Submodule for Modular Multilevel Converter

The modular multilevel converter (MMC) has been widely used in the field of high-voltage direct current (HVDC) transmission and motor drivers due to its many advantages. As voltage sensors and sorting algorithm are often used to depress the voltage fluctuation of submodules (SMs), it suffers from the algorithm complexity and hardware cost, especially for a large number of output levels. In this article, a new clamp-double-SM (CDSM) composed of two capacitors and five transistors is proposed. The symmetrical operation of the two capacitors enables the CDSM to output three levels and their voltages are self-balanced. Moreover, the capacitor voltages among different SMs of a CDSM-based MMC are also self-balanced by adding two auxiliary balance branches between adjacent CDSMs. It means that the new MMC can operate normally without using complex balancing algorithms based on capacitor voltage sorting. Compared with existing self-balanced MMCs, the new MMC uses fewer components in both the main power topology and auxiliary balancing circuits. In addition to topology, modulation, parameter design, and power loss are analyzed in detail. Finally, the feasibility of the CDSM-based MMC is verified by simulation and experimental results.

Analysis of Modification of Car AC Compressor to Split AC Compressor on Cooling Rate

Refrigeration or cooling technology is increasing, especially regarding the coolant, almost all new vehicles now use air conditioning to condition the air in the vehicle cabin, but there are still many aspects that currently have not been paid much attention, especially to compressors, compressors for now still rely on the engine as a direct driver which makes fuel consumption more wasteful and reduces the performance of the vehicle. The purpose of this research is to modify a conventional compressor into an electric compressor by utilizing a split ac compressor. The research method uses the direct experimental method, can a split ac compressor replace a conventional compressor. Testing without changing a lot of the cooling system on the car, only changing the compressor without any other changes. The results of the research on split ac compressors can be applied to cars, but the cooling rate is slower than car ac compressors.

Assessing policies to reduce adolescent overweight and obesity: Insights from a system dynamics model using data from the Health Behavior in School-Aged Children study.

Adolescent overweight and obesity (AdOWOB) in Europe has proven to be a persistent and complex problem, and appropriate systems methods may help in evaluating potential policy options. This paper describes the development of a system dynamics model of AdOWOB as part of the EU-funded CO-CREATE project. The model was developed using literature and data from the Health Behavior in School-Aged Children (HBSC) study across 31 European countries. We identified 10 HBSC variables that were included as direct or indirect drivers of AdOWOB in the dynamic model, seven at the level of the individual, and three related to the social environment. The model was calibrated to 24 separate cases based on four gender and perceived wealth segments for each of the five CO-CREATE countries (The Netherlands, Norway, Poland, Portugal, and the UK) and for Europe overall. Out of 10 possible intervention points tested, exercise, fruit, life dissatisfaction, school pressure, and skipping breakfast were identified as the top five most influential ones across the 24 cases. These model-based priorities can be compared with the policy ideas suggested by the CO-CREATE adolescents.

Exploring the Ecological Performance of China's Tourism Industry: A Three-Stage Undesirable SBM-DEA Approach with Carbon Footprint.

The environmental impact of carbon emissions and the carbon footprint from tourism activities are significant for promoting low-carbon development in the tourism industry. This paper employed a bottom-up approach to estimate the carbon footprint and energy consumption of China's tourism industry. Then, the three-stage undesirable SBM-DEA model was employed to evaluate and decompose the eco-efficiency of China's provincial tourism industry from 2008 to 2017. The results showed that the eco-efficiency of most provinces has experienced a slight increase during the past ten years, while management inefficiency within the tourism industry has been the main restriction of the utilization of tourism resources in most regions. The decomposition and quadrant analysis indicated that scale efficiency was the direct driver of the poor ecological performance in Northeast China, while technical efficiency dominated the tourism eco-efficiency in South-Central China. These two issues have together led to the poor utilization of the rich tourism resources and the natural environment in Southwest China. On the basis of these discussions, differentiated policy implications towards different kinds of regions were provided to promote low-carbon development and to realize the potential of tourism resources in China's tourism industry.

New Dimension on Quality of Life Differences among Older Adults: A Comparative Analysis of Digital Consumption in Urban and Rural Areas of China.

The purpose of this study was to compare the variability in quality of life in the area of digital consumption among older adults in urban and rural China during the COVID-19 pandemic. This study proposed a low-cost mixed research method, and the methodology used a quantitative study of a large regional sample combined with a qualitative study of a small regional sample. Data for the large-scale area sample were obtained from the China family panel study (CFPS) dataset, and data for the small-scale regional sample were obtained from Nanjing, China. The quantitative analysis of the large-scale regional sample used the least squares regression analysis (OSL) and propensity score matching (PSM). The qualitative analysis of the small-scale regional sample used the selection optimization and compensation (SOC) model. The findings show that economic income is a direct driver of digital consumption. Digital consumption had a significant positive relationship with the quality of life for urban and rural older adults. In addition, the study established the semantic network relationships of the coping strategies of digital consumption of older adults and their drivers. Finally, the theoretical and practical implications of these findings are discussed in the context of other related studies.

The direct drivers of recent global anthropogenic biodiversity loss.

Effective policies to halt biodiversity loss require knowing which anthropogenic drivers are the most important direct causes. Whereas previous knowledge has been limited in scope and rigor, here we statistically synthesize empirical comparisons of recent driver impacts found through a wide-ranging review. We show that land/sea use change has been the dominant direct driver of recent biodiversity loss worldwide. Direct exploitation of natural resources ranks second and pollution third; climate change and invasive alien species have been significantly less important than the top two drivers. The oceans, where direct exploitation and climate change dominate, have a different driver hierarchy from land and fresh water. It also varies among types of biodiversity indicators. For example, climate change is a more important driver of community composition change than of changes in species populations. Stopping global biodiversity loss requires policies and actions to tackle all the major drivers and their interactions, not some of them in isolation.

Trade-offs and synergistic relationships of ecosystem services under land use change in Xinjiang from 1990 to 2020: A Bayesian network analysis

Ecosystem service value (ESV) refers to the value of benefits provided by the ecosystem to people, and can reflect the quality of regional ecological environment. There have been few studies on ESV in arid regions experiencing dramatic land use changes. Also, many past ESV studies have obtained distorted results by using a simple linear function to examine the trade-offs between driving factors. This study quantified ESV in Xinjiang from 1990 to 2020 based on value equivalent method. Differences in ESV among ecosystem services in Xinjiang under different scenarios were simulated using a Bayesian network model. The results demonstrated land use changes in Xinjiang from 1990 to 2020, with construction land expanding the most significantly (dynamic index: 224.63 %), whereas grassland area decreased (dynamic index: −1.31 %) due to transformation to unused and cultivated land. ESV in Xinjiang presented an N-shaped variation trend from 1990 to 2020 and decreased by 309.6 × 108 CNY, with a variation rate of −20.35 %. The rank of the four categories of ecological services from 1990 to 2020 in terms of ESV was: regulating services > support services > cultural services > supply services. There was a gradual reduction in ESV in Xinjiang from 1990 to 2020. The rank of the different regions in terms of the reduction in ESV was: Northern Xinjiang (295.24 × 108 CNY) > Southern Xinjiang (280.94 × 108 CNY) > Eastern Xinjiang (109.76 × 108 CNY). Land use change was a direct driver of changes in ESV, whereas natural and social factors, such as precipitation, temperature, population, and policy factors, were indirect drivers. This study can act as a reference for sustainable management of ecosystem services in arid regions.

Forest ecosystem services in Norway: Trends, condition, and drivers of change (1950–2020)

Some regions like Europe have experienced a net gain in forest areas over the last decades, but intact areas of natural forests are declining worldwide, accompanied by changes in forest ecosystem functions and benefits to humans. We conduct a biophysical assessment of trends, condition, and drivers of change of forest ecosystem services in Norway from 1950 to 2020. Four main results are highlighted. First, industrial forestry, large scale measures of re- and afforestation, and infrastructure development (e.g., roads and recreational homes) have been the main direct drivers of forest transformation. Second, deep transformations in the Norwegian economy shaped trends of forest ecosystem services over the study period. Third, with the shifts towards the tertiary (service) sector and the mechanization of forestry, the economic and material relations between forests and local communities are waning. Overall, people’s primary relationships to forests have shifted from livelihood to recreation. Fourth, forest management in Norway has largely favored provisioning services at the expense of supporting services and some cultural and regulating services. Consequently, while Norwegian forests retain strong capacity to deliver provisioning services, the overall ecological condition is relatively poor. Our assessment provides an approach to identify and explain trends of ecosystem services at a national scale, over a long period of time. We argue that growth in forest area and biomass are insufficient indicators for sustainable forest management, and that future forest polices would benefit from improved knowledge on forests ecological condition, resilience against climate change, and socio-cultural contributions to human well-being.

Is “Common But Differentiated Responsibilities” principle applicable in biodiversity? – Towards approaches for shared responsibilities based on updated capabilities and data

The application of the “Common But Differentiated Responsibilities (and Respective Capabilities)” (CBDR-RC) principle in the field of biodiversity received criticisms due to the lack of scientific evidence and/or outdated categories which in turn resulted in a knowledge gap in its applicability in policy-making. Reflecting on this research gap, we reviewed existing relevant publications by quantifying and evaluating the responsibility of different countries under various categories (i.e., low-, middle-, and high-income) for biodiversity loss. As concrete indicators, we used the five direct drivers of biodiversity loss by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) to examine and identify biodiversity-related footprints and challenges, whereby the applicability of the CBDR principle was considered. Data on the national impact and positive contributions to global biodiversity were also encompassed, considering all available data from older periods as possible. The results showed that low-, middle-, and high-income countries contributed to biodiversity loss, with high-income countries as the largest contributor, indicating relatively high responsibility by developed countries. Meanwhile, developing (middle- and low-income) countries contributed about 44% of biodiversity loss. The results further indicated that the shared responsibility was not clear enough to be sorted out by a simple dichotomy between developed and developing countries and immediately applying the CBDR principle. Besides, the impact of global trade should be fairly attributed to consumer countries (frequently developed countries) and producer countries (developing countries). Moreover, the upward move in the income category in many countries in the last decades has not been fully reflected in discussions under the Convention on Biological Diversity. This means that the respective capabilities have not been considered in a timely manner in policy-making. As such, we propose non-binary “Differentiated But Shared Responsibilities (and Updated Capabilities)” (DBSR-UC) as a new concept, highlighting the need for incentives and burdens based on scientific evidence.

FOXA2 drives lineage plasticity and KIT pathway activation in neuroendocrine prostate cancer.

Prostate cancer adeno-to-neuroendocrine lineage transition has emerged as a mechanism of targeted therapeutic resistance. Identifying the direct molecular drivers and developing pharmacological strategies using clinical-grade inhibitors to overcome lineage transition-induced therapeutic resistance are imperative. Here, using single-cell multiomics analyses, we investigate the dynamics of cellular heterogeneity, transcriptome regulation, and microenvironmental factors in 107,201 cells from genetically engineered mouse prostate cancer samples with complete time series of tumor evolution seen in patients. We identify that FOXA2 orchestrates prostate cancer adeno-to-neuroendocrine lineage transition and that Foxa2 expression is significantly induced by androgen deprivation. Moreover, Foxa2 knockdown induces the reversal of adeno-to-neuroendocrine transition. The KIT pathway is directly regulated by FOXA2 and specifically activated in neuroendocrine prostate cancer (NEPC). Pharmacologic inhibition of KIT pathway significantly suppresses mouse and human NEPC tumor growth. These findings reveal that FOXA2 drives adeno-to-neuroendocrine lineage plasticity in prostate cancer and provides a potential pharmacological strategy for castration-resistant NEPC.

The impact of lactose type on disintegration: An integral study on porosity and polymorphism

Besides factors such as disintegrant and lubricant, the raw material properties of filler excipients can have an impact on the disintegration behavior of a tablet. The current research aims to model the impact of lactose properties on disintegration time. For the first time, the impact of lactose polymorphism, tablet tensile strength, and pore structure parameters on disintegration were evaluated in one study. Six different lactose qualities were compacted into tablets of different solid fractions in a formulation with 5 %w/w diclofenac sodium, 1 %w/w magnesium stearate and 2 %w/w croscarmellose sodium. A linear model was built to identify which parameters impact the disintegration time, using as potential variables the polymorphic composition of the lactose, the porosity, pore size distribution and the tablet tensile strength. The model variables were derived from literature and calibrated with data. After optimization, the model shows a strong correlation (r2 = 0.982) between measured and predicted disintegration times. Among all investigated variables, the polymorphic composition of lactose, and the pore size distribution have been identified to affect tablet disintegration most. A higher concentration of lactose monohydrate in tablets leads to faster tablet disintegration, explained by the slower dissolution rate of lactose monohydrate compared to anhydrous and amorphous lactose. Tablet tensile strength was not identified as a direct driver for disintegration. Instead, the pore size distribution is a mutual driver for both tablet tensile strength and disintegration. The obtained insights provide guidance on the importance of quality attributes of filler binders for the prediction of tablet disintegration. This study can therefore be used as a starting point for quality-by-design formulation development and for the development of mechanistic models to predict tablet disintegration.

Conceptualizing Different Forest Degradation Drivers with Special Reference to India

Forest deterioration has been a global issue in the 21st century as one of the most serious environmental issues. The costs of forests degradation is in reducing productivity and natural resources such as water, land, grassland etc. Deforestation affects the whole globe but it is of main concern of developing countries of the Tropics. Forest deterioration and deforestation are caused by a variety of factors that vary depending on the location. The main aim of the review is to analyse various forest degradation drivers and to establish keys to estimate the level of degradation. The various direct and indirect drivers of forest degradation are excessive mining, selective logging, population explosion, climatic-change, forest fires, biological invasion, agricultural land expansion and weak forest administration. One sort of sustainability in a managed forest is the system of several landowners, each with a modest multifunctional, multispecies plot. Other plan for sustainable development is eco-development programme, which is inter and multi-stakeholder method for connecting the conservation benefits of protected areas with community people's livelihoods and development practices in the environments around them. A shift toward whole-landscape management is required, with a focus on places with high levels of usage mixed with areas principally maintained for conservation, recreation, and water catchment. Some guidelines are being created, but more interactions between ecologists, foresters, social scientists, and economists are urgently needed.

Spatial and temporal variability of phytoplankton photophysiology in the Atlantic Southern Ocean

Active chlorophyll-a fluorescence was measured during five summer research cruises (2008 – 2016), spanning the Atlantic sector of the Southern Ocean. This unique data set provides information for assessing zonal, inter-annual and intra-seasonal variability (early versus late summer) of photosynthetic efficiency (Fv/Fm). The zonal variability of Fv/Fm showed a typical latitudinal decline from a maximum in the Polar Frontal Zone (PFZ) (0.24±0.03) to a minimum in the Southern Antarctic Circumpolar Current Zone (SACCZ) (0.18±0.07). The inter-annual variability in Fv/Fm (between each cruise) was the highest in the SACCZ, while the Antarctic Zone (AZ) exhibited low inter-annual variability. Intra-seasonal variability between the zones was limited to a significantly higher mean Fv/Fm in the PFZ and AZ in early summer compared to late summer. Intra-seasonal variability between the cruises was, however, inconsistent as higher mean Fv/Fm in early summer were seen during some years as opposed to others. Ancillary physical and biogeochemical parameters were also assessed to investigate potential direct and indirect drivers of co-variability with Fv/Fm through a series of statistical t-tests, where significant differences in Fv/Fm were used as focus points to interrogate the plausibility of co-variance. Inter-zonal variability of surface seawater temperature (SST) and Silicate:Phosphate (Si:P) ratios were highlighted as co-varying with Fv/Fm in all zones, whilst community structure played an indirect role in some instances. Similarly, inter-annual variability in Fv/Fm co-varied with SST, Nitrate:Phosphate (N:P) and Si:P ratios in the PFZ, AZ and SACCZ, while community structure influenced inter-annual variability in the PFZ and SACCZ. Intra-seasonal variability in Fv/Fm was linked to all the ancillary parameters, except community structure in the AZ, whilst different ancillary parameters dominated differences during each of the cruises. These results were further scrutinized with a Principal Component Analysis for a subset of co-located data points, where N:P and Si:P ratios emerged as the principal indirect drivers of Fv/Fm variability. This study highlights the scope for using Fv/Fm to reflect the net response of phytoplankton photophysiology to environmental adjustments and accentuates the complex interplay of different physical and biogeochemical parameters that act simultaneously and oftentimes antagonistically, influencing inter-zonal, inter-annual and intra-seasonal variability of Fv/Fm.

Environmental microbiology going computational-Predictive ecology and unpredicted discoveries.

Environmental microbiology going computational-Predictive ecology and unpredicted discoveries.

Drivers for the artisanal fisheries production in the Magdalena River

We review knowledge on the Magdalena River in Colombia and its fish to identify those drivers that influence the artisanal fisheries production. We identify eight direct drivers (four natural and four anthropogenic) and at least four indirect drivers. Those drivers modify conditions in the fluvial network that promote fish movements, reproduction, and their larvae survivor. Landscape, rains, floods, connectivity of the fluvial net as land cover change, water pollution, hydropower, and alien species are the natural and anthropogenic direct drivers described in this article. The river–lake interaction dynamics in the Magdalena River are determined by two rainy cycles per year. Two seasonal flooding periods induce two cycles in the biological productivity of floodplains because water and sediment inputs. The most visible consequences in these hydrological cycles are the migrations of potamodromous fish and the periodic increase in the artisanal fishery production. Major floodplains are reducing their storage capacity by trapping ∼10%–40% of upstream sediment production. This process induces many research questions about rates of biomass production, carbon fluxes in the basin, impacts of human-induced erosion, and increasing rates of sediment load on floodplain connectivity, but still there is not enough data to answer them. Finally, we make some suggestions toward the sustainability of the Magdalena floodplains. The well-being of the floodplain ecosystems and their connectivity with the main river are the main tools to preserve and manage the ecosystem services of the Magdalena River and its floodplains lakes.

A perceptual study of relationship between emotional intelligence and job performance among higher education sector employees in Saudi Arabia

PurposeThe purpose of this research is to investigate faculties' perceptions of emotional intelligence about job performance (task and contextual performance (TP and CP)) in the higher education sector in the Kingdom of Saudi Arabia.Design/methodology/approachThis research employed an explanatory research design method. A quantitative design approach is adopted by implementing a survey-based study. Quantitative data have been collected anonymously from faculty members (n = 277) working in different higher educational institutes in Saudi Arabia.FindingsThe research findings revealed a positive relationship between others' emotions appraisal and use of emotions with CP, whilst all the dimensions of emotional intelligence, namely self-emotions appraisal (SEA), others' emotions appraisal (OEA), use of emotions (UOE) and regulation of emotions (ROE) revealed a significant positive relationship with the TP. Nevertheless, the research supports the argument that emotional intelligence is considered an essential contributor to faculty members' job performance.Practical implicationsThis research study provides empirical support for the argument that emotional intelligence is a direct driver for enhancing job performance through the appraisal, use and regulation of emotions. In terms of practical implications, the research findings will encourage higher education institutions to take specific actions that will help to enhance awareness of and build emotional intelligence skills amongst faculty staff.Originality/valueThis study is the first that has sought to investigate the impact of emotional intelligence on employees' performance in the Saudi Arabian higher education sector. Additionally, this study has developed a new psychometric scale that is useful in the higher education sector.

Objective assessment of vehicle controllability in straight-line motion

Introduction (statement of the problem and relevance). The problem of vehicle handling and stability during rectilinear motion was raised in the first half of the 20th century, and today this issue is still relevant. The requirements for handling, including during rectilinear movement of modern cars, are getting tougher. Straight-line stability and long-distance directional stability affect driver's fatigue, his driving safety and pleasure, as well as car fuel efficiency. Besides it, to provide modern driver assistance system, the car should possess good straight-line stability. At the same time, the design mustn't be affected by unbalanced forces and torques that could cause the trajectory deviation of the vehicle. There comes a need for an objective controllability and stability assessment of the car in a straight line.The purpose of the research was to analyze the existing methods for studying rectilinear motion controllability, to develop objective parameters for evaluating such motion, and to apply the worked out solutions when analyzing vehicle tests results.Methodology and research methods. Mathematical analysis, comparison, experiments, measurements were applied as research methods.Scientific novelty and results. The results have been presented in the form of a developed straight motion evaluation parameters list and were processed by calculating objective evaluation parameters. The scientific novelty is presented by the parameters of the driver's work objective assessment, and the first step has been made to correlate the objective and subjective assessment of the test driver.Practical significance. The developed method of the objective assessment can be applicable to all vehicles with traditional steering control.

Effects of changing temperature phenology on the abundance of a critically endangered baleen whale

Incorporating the effects of climate change in species management strategies is one of today’s greatest conservation challenges. Mechanistic models can be used to address these challenges because they explain how climate change effects cascade through ecosystems and influence species distributions. We used structural equation models to test hypotheses about the cascading effects of climate change and basin-scale variables on the local abundance of North Atlantic right whales, a critically endangered species, in a historically important feeding habitat. We found that effects of the North Atlantic Oscillation, a basin-scale variable, on local right whale abundance occurred through a cascade of effects on other ecosystem variables, including chlorophyll a concentration, Calanus finmarchicus abundance, and zooplankton patchiness. These effects varied by month. We also found that the western Gulf of Maine spring thermal transition date (a proxy for climate change) is a major direct and indirect driver of variations in local right whale abundance. The indirect effect of earlier spring transition dates, through a pathway of prey abundance, suggested a decrease in local right whale abundance. However, right whale abundance increased because of the direct effect of regional spring transition date. The direct effect suggests that right whales may be using regional temperatures as a movement cue. The counter-acting direct and indirect effects of spring transition date suggest that right whales could face a mismatch with their prey, which could ultimately result in another large-scale distribution shift. Our causal modeling approach demonstrates that the influence of climate change on local right whale abundance in the Gulf of Maine cascades through a network of variables. These cascading effects make predicting local right whale abundance challenging and suggest that successful endangered species conservation requires identifying the mechanisms underlying species distributions.

Drivers of land-use and land-cover change in rural landscapes; a case in Eastern Sierra Leone

This study provides the first attempt at assessing the drivers of LULC change in eastern Sierra Leone where settlement expansion is as eminent as the proliferation of the primary industrial sector, notably agriculture and artisanal mining. For this purpose, using Landsat images at 1986, 2000 and 2020, LULC maps of the study area were obtained. The principal drivers of LULC change were identified based on field observations and interviews with local residents. Additionally, population and climate data were obtained to better understand LULC changes. Vast changes were observed in Shrub/Fallow, Grass/Cropland, Wetland and Built/Barren. Moderate changes were observed in Trees/Forest and Open Water. The drivers of LULC change are attributable to population growth as the main underlying driver and agricultural expansion and infrastructural development as the main proximate or direct drivers. Moreover, the declining rainfall in tandem with rising temperatures can be linked to the shrinking Wetland and Open Water.

Gray Luvisols are polygenetic

With respect to the pedosphere, human activities in the last 100 years have been the major driver of soil change. Despite human activities being one of the main soil forming factors recognized by soil scientists (in addition to climate, organisms, parent material, relief, groundwater, and time), the Canadian System of Soil Classification (CSSC) emphasizes soil as a natural body. We argue human agricultural activities are direct and indirect drivers of significant changes to the carbon balance and cycling in A horizons of Gray Luvisolic soils in western Canada, resulting in changes to A horizon carbon stocks, structure, and micromorphology. Evidence from scientific literature, in-field soil profile observations, and the National Pedon Database are presented in support of our argument. We propose a polygenetic, two-stage model of Gray Luvisol soil formation. The first stage is dominated by the climate forcing of the Holocene, resulting in a relatively stable boreal forest ecosystem including perturbations from natural and human-induced wildfire and other disturbances. The second stage is dominated by direct, human-driven disturbances such as cultivation, release of exotic fauna (earthworms), and indirect human-driven disturbances associated with anthropogenic climate change. Further, we propose modest amendments to the CSSC to reflect a polygenetic model of soil genesis in Gray Luvisolic soils that preserve the balance between observation and interpretation inherent in the system.