Dominant Force Research Articles

Animal migration in the Anthropocene: threats and mitigation options.

Animal migration has fascinated scientists and the public alike for centuries, yet migratory animals are facing diverse threats that could lead to their demise. The Anthropocene is characterised by the reality that humans are the dominant force on Earth, having manifold negative effects on biodiversity and ecosystem function. Considerable research focus has been given to assessing anthropogenic impacts on the numerical abundance of species/populations, whereas relatively less attention has been devoted to animal migration. However, there are clear linkages, for example, where human-driven impacts on migration behaviour can lead to population/species declines or even extinction. Here, we explore anthropogenic threats to migratory animals (in all domains - aquatic, terrestrial, and aerial) using International Union for the Conservation of Nature (IUCN) Threat Taxonomy classifications. We reveal the diverse threats (e.g. human development, disease, invasive species, climate change, exploitation, pollution) that impact migratory wildlife in varied ways spanning taxa, life stages and type of impact (e.g. from direct mortality to changes in behaviour, health, and physiology). Notably, these threats often interact in complex and unpredictable ways to the detriment of wildlife, further complicating management. Fortunately, we are beginning to identify strategies for conserving and managing migratory animals in the Anthropocene. We provide a set of strategies that, if embraced, have the potential to ensure that migratory animals, and the important ecological functions sustained by migration, persist.

Cell and gene therapy investment: evolution and future outlook on investor perspectives

Background aimsTo better understand the attitudes and behaviors of investors involved in funding cell and gene therapy (CGT) businesses, the Business Development and Finance) subcommittee of International Society for Cell and Gene Therapy, in collaboration with Truist Securities, conducted a broad survey of the investment community in late 2021. MethodsThis survey follows a similar study that this group executed in 2018, and the longitudinal comparisons between the two time periods provide insights into how investor behavior in the CGT field has evolved. ResultsThe vast majority of investor respondents are specialist biotech investors who are primarily active in deploying capital in North America and Europe. There was a notable increase in the proportion of investors actively deploying capital in China and Japan between 2018 and 2021. The percentage of respondents’ portfolios dedicated to CGT companies has also increased in this period, reflecting a noteworthy trend in the therapeutic landscape. ConclusionsClinically significant data remain the dominant force behind investment decisions, whereas competition from other drug modalities has now emerged as the most-cited barrier to making a CGT investment, eclipsing safety concerns as the most significant barrier to investment in 2018. Concerns around manufacturing and scale-up have also increased in prominence amongst the investment community. Gene-editing technologies are attracting investors as the most compelling new CGT technology. This survey also revealed that most investors expect to increase their level of investment in allogeneic technologies relative to autologous products in the coming years.

EDUCATION SYSTEM IN MEDIEVAL PERIOD - THE IMPACT OF SCHOLASTICISM ON MEDIEVAL LEARNING

This study explores the impact of scholasticism on medieval learning, focusing on its influence within the educational landscape also it investigates how scholastic methods, epitomized by the works of thinkers such as teaching methodologies, shaped curriculum, and intellectual climate of medieval institutions. Scholasticism, characterized by its importance on hard dialectical reasoning and the reconciliation of reason and faith, became a dominant intellectual force in medieval education. One sample test and ANOVA has been used for this research to analyse the impact of scholasticism on medieval learning. The medieval period, roughly spanning from 5th to 15th century, was characterized by a unique set of political, social, and cultural dynamics. In terms of education, this time witnessed the dominance of system deeply rooted in religious institutions and influenced by the attitude of scholasticism. The medieval period saw the traditional Indian educational systems with the introduction of Islamic influences. Islamic rulers established madrasas, centers of learning that focused on religious studies. The gurukul system continued, emphasizing disciplines such as literature, mathematics, philosophy and science. The government need to undertake initiatives to expand access to education, resulting in establishment of schools, colleges, and universities. The focus on science, technology, and vocational training became pronounced, aiming is to meet the demands of a fast changing global landscape. The Indian education system reveals the continuous effort to build a more flexible, and responsive educational framework for the diverse needs of the country.

The Father as a Dominant Figure in John McGahern’s The Dark

The aim of this article is to investigate the role of the father figure in John McGahern’s novel, The Dark. Accordingly, the researcher attempts to examine the relationships between fathers and sons, and the psychological impact of dominant father figures on their children. For the theoretical framework of the study, the researcher draws on the father/ child Relationship in psychology. The analytical approach is employed to analyse the father’s actions and attitudes towards his family members. Through a close reading of the text, the researcher reaches the conclusion that the father figure in the novel is portrayed as a dominant and oppressive force, leading to the protagonist’s psychological and emotional struggles.The concepts of dominant and oppressive forces are often discussed in various fields, including sociology, politics, and cultural studies. These terms are used to describe power dynamics and the ways in which certain individuals, groups, or institutions exert control over others. The presence of a dominant father figure can significantly shape the identity and development of the characters, especially if the narrative unfolds within a family context. The expectations, values, and behaviours imposed by the dominant father can influence how individuals perceive themselves and their roles in the world. This impact might lead to internal conflicts and struggles for autonomy. Psychological abuse has been linked with negative outcomes such as impaired emotional, social, and cognitive development, including helplessness, aggression, emotional unresponsiveness and neuroticism (Black et al., 2001)

Does backflow occur in forced imbibition into a dual-permeability pore network?

Backflow is a typical flow phenomena in two-phase displacement, but it is rarely studied in the forced imbibition and it remains unknown if the backflow occurs in forced imbibition into a porous medium. In this paper, we focus on the forced imbibition and investigate the backflow behavior in pore doublet (PD) models and in dual-permeability pore networks. Inspired by Gu et al. (2021) and Shan et al. (2023), a general mathematical model is first developed to predict the evolution of the penetration length of wetting fluid in a PD with arbitrary initial interface locations. Based on the analytical predictions and numerical simulations, we then study the influence of initial interface location, capillary number, viscosity ratio, and channel width ratio on the backflow. Results show that the backflow in a PD is mainly attributed to high flow rate in narrow channel, driven by the dominant capillary force. To supplement the insufficiency of inlet flow rate, the fluid in wide channel has to flow backwards to fill the narrow channel. The backflow strengthens with the decrease of capillary number or viscosity ratio, but it exhibits non-monotonic variation with initial interface location and channel width ratio. Moreover, the phase diagrams showing the critical conditions for the occurrence of backflow are established in terms of capillary number, viscosity ratio and channel width ratio. Finally, numerical simulations are conducted to explore the occurrence of backflow in three different dual-permeability pore networks. It is found that the backflow does not occur in dual-permeability pore networks due to the low flow rate caused by overlap event and pronounced tortuosity in the low permeability zone, or occurs only in the early stage when the capillary valve effect does not work.

Diazotrophic community in the sediments of Poyang Lake in response to water level fluctuations.

Water level fluctuations (WLFs) are typical characteristic of floodplain lakes and dominant forces regulating the structure and function of lacustrine ecosystems. The sediment diazotrophs play important roles in contributing bioavailable nitrogen to the aquatic environment. However, the relationship between the diazotrophic community and WLFs in floodplain lakes is unknown. In this paper, we carried out a comprehensive investigation on the alpha diversity, abundance, composition and co-occurrence network of the sediment diazotrophs during different water level phases in Poyang Lake. There were no regular variation patterns in the alpha diversity and abundance of the sediment diazotrophs with the water level phase transitions. The relative abundance of some diazotrophic phyla (including Alphaproteobacteria, Deltaproteobacteri, Euryarchaeota, and Firmicutes) and genera (including Geobacter, Deferrisoma, Desulfuromonas, Rivicola, Paraburkholderia, Methylophilus, Methanothrix, Methanobacterium, and Clostridium) was found to change with the water level phase transitions. The results of ANOSIM, PerMANOVA, and DCA at the OTU level showed that the diazotrophic community structure in the low water level phase was significantly different from that in the two high water level phases, while there was no significant difference between the two high water level phases. These results indicated that the diazotrophic community was affected by the declining water level in terms of the composition, while the rising water level contributed to the recoveries of the diazotrophic community. The diazotrophs co-occurrence network was disrupted by the declining water level, but it was strengthened by the rising water level. Moreover, redundancy analysis showed that the variation of the diazotrophic community composition was mostly related to sediment total nitrogen (TN) and total phosphorous (TP). Interestingly, the levels of sediment TN and TP were also found to vary with the water level phase transitions. Therefore, it might be speculated that the WLFs may influence the sediment TN and TP, and in turn influence the diazotrophic community composition. These data can contribute to broadening our understanding of the ecological impacts of WLFs and the nitrogen fixation process in floodplain lakes.

Contribution of interphase force curl to rigid vorticity transport in water-sand two-phase flow with fine particles

Rigid vorticity transport equation is an effective tool for describing the intuitive vortex evolution characteristics. Compared to single-phase flows, the curl of the interphase force appears as a new source term of this equation under the condition of multiphase flows, which may cause additional contributions. However, the effects of the interaction force on rigid vorticity transport in water-sand two-phase flows with fine particles are still unclear. In this article, taking the Karman vortices induced by a hydrofoil as a typical case, the distributions of rigid vorticity in single-phase flows and two-phase flows were compared, and the dynamics mechanism of the dominant interaction force was analyzed. The following notable results are obtained. Firstly, the drag force can be regarded as the dominant interaction force. Secondly, the effect of the drag force on a vortex tube is mainly manifested as inducing normal strain and the contribution is relatively low. Thirdly, there are only slight differences in the waveform, amplitude, frequency of rigid vorticity and apparent vortical structures between the single-phase flows and the fine-particle two-phase flows. These new findings are helpful for understanding the vortex evolution in water-sand two-phase flows with fine particles.

The direct Monte Carlo simulation of microchannel flows for a large Knudsen number range

In recent years, porous materials containing micro- and nano-scale pores have found widespread applications. As the pore size decreases in such materials, rarefaction effects become significant in the pore flow, making the study of flow characteristics under higher Knudsen number conditions particularly crucial. In this work, through a direct simulation Monte Carlo (DSMC) method, an in-depth investigation is conducted into the gas flow characteristics and Klinkenberg effect in porous media with pore sizes ranging from 1 nm to 50 μm and Knudsen numbers spanning from 0.02 (slip flow) to 1200 (free molecular flow). The feasibility of using the DSMC method to simulate an internal free molecular flow in a porous medium under extreme rarefaction conditions with a Knudsen number of 1200 is validated. Furthermore, the impact of the gas pressure and porous medium pore size on the permeability is examined. The results reveal that with an increase in the Knudsen number, the dominant forces in the flow field transition from viscous forces to Knudsen diffusion, leading to a gradual increase in permeability. A comparative analysis reveals that existing apparent permeability models only provide satisfactory descriptions under certain Knudsen number conditions. Re-fitting the coefficient of the Kawagoe model and incorporating viscosity corrections leads to an apparent permeability model that can provide good predictions over a broader range of Knudsen numbers.

Ionospheric Disturbances Generated by the 2015 Calbuco Eruption: Comparison of GITM‐R Simulations and GNSS Observations

AbstractVolcanic eruptions provide broad spectral forcing to the atmosphere and understanding the primary mechanisms that are relevant to explain the variety in waveform characteristics in the Ionosphere‐Thermosphere (IT) is still an important open question for the community. In this study, Global Navigation Satellite System (GNSS) Total Electron Content (TEC) data are analyzed and compared to simulations performed by the Global Ionosphere‐Thermosphere Model with Local Mesh Refinement (GITM‐R) for the first phase of the 2015 Calbuco eruption that occurred on 22 April. A simplified source representation and spectral acoustic‐gravity wave (AGW) propagation model are used to specify the perturbation at the lower boundary of GITM‐R at 100 km altitude. Two assumptions on the propagation structure, Direct Spherical (DS) and Ground Coupled (GC), are compared to the GNSS data and these modeling specifications show good agreement with different aspects of the observations for some waveform characteristics. Most notably, GITM‐R is able to reproduce the relative wave amplitude of AGWs as a function of radial distance from the vent, showing acoustic dominant forcing in the near field (<500 km) and gravity dominant forcing in the far‐field (>500 km). The estimated apparent phase speeds from GITM‐R simulations are consistent with observations with ∼10% difference from observation for both acoustic wave packets and a trailing gravity mode. The relevance of the simplifications made in the lower atmosphere to the simulated IT response is then discussed.

Bank depositors in Arab economies amidst the COVID-19 pandemic

This study investigates the multifaceted impacts of COVID-19, GDP, exchange rates, unemployment, and economic policy uncertainty on bank depositors in Arab economies: Algeria, Comoros, Djibouti, Egypt, Iraq, Jordan, Lebanon, Libya, Mauritania, Morocco, Palestine, Somalia, Sudan, Syria, Tunisia, and Yemen, between 2017 and 2022. Using ordinary least square analysis, the research uncovers significant relationships between these variables and banking indicators. COVID-19 has emerged as a dominant force, displaying a substantial and adverse link to the number of deposit accounts and depositors. While GDP, exchange rates, unemployment, and economic policy uncertainty also exhibit influences on banking metrics, their effects are comparatively smaller. This underscores the pandemic’s exceptional sway over banking behaviors within the region, emphasizing the pressing need to address COVID-19’s implications for financial stability and strategies to reinforce banking resilience amidst diverse economic challenges.

Into the meme stream: The value and spectacle of Internet memes

This article ‘tracks’ memes, forms of networked, pictorial/caption humour and social commentary – as well as cultural labour, through a process of value change: the ‘meme stream’. This is a process of incorporation of cultural resistance and labour into, and by, the dominant forces of capital that facilitate them: social media networks and their advertisers. We use Marcuse’s Repressive Tolerance alongside Debord’s Spectacle to argue that as memes move, increasing their audience as they go, they lose resonance with a dedicated audience but gain exposure with a more diffuse audience, which is detrimental to the expression of political, countercultural or socially provocative positions. We use Doge as our explanatory structural example. Our contribution is to demonstrate that the systems that allow for the flow and movement of memes reduce their expressive content, shifting them towards a template that is impotent for cultural, social or political critique.

Effects of selfing on the evolution of sexual reproduction.

Plants exhibit diverse breeding systems, with populations capable of outcrossing, selfing, and/or asexual reproduction. However, interactions between the three reproductive pathways remain not fully clear. Sexual reproduction introduces segregation and recombination, but incurs several costs. Selfing can affect the relative costs and benefits of sexual vs. asexual reproduction. Building population genetic models, I explore how selfing affects the evolution of a sexual reproduction rate modifier via (a) indirect selection due to segregation, (b) indirect selection from changes in recombination rates, and (c) selection from the cost of meiosis and mate limitation. The dominant selective force mediating the evolution of sex is found to vary with the rate of sexual reproduction and selfing, but selective force (a) and (c) are generally stronger than selective force (b). A modifier enhancing sexual reproduction tends to be favored by indirect selection generated by partially recessive, small-effect deleterious mutations, while hindered by highly recessive lethal mutations. Overall, evolution toward higher sexual reproduction is hindered at low sexual reproduction rates and intermediate selfing rates, but favored under high selfing rates. The results suggest that asexual reproduction may precede the evolution of selfing and offer insights into the evolution of mechanisms reducing geitonogamy in partially clonal populations.

Balancing the Water-Carbon Trade-Off: Development of a Bi-Level Source-Grid-Load Synergistic Optimization Model for Multi-Regional Electric Power System

This study introduces the Bi-Level Source-Grid-Load Synergistic Optimization (BL_SGLSO) model, which effectively balances the competing objectives of water conservation and carbon emission reduction in the power industry. The model aims to establish a clean and low-carbon electric power system by harmoniously reconciling these two critical goals. Through the application of bi-level programming, the BL_SGLSO model adeptly manages the preferences and conflicts of decision makers at various levels while capturing regional interactions and the intricacies of electricity transmission. Key findings reveal that non-fossil energy conversion technologies are poised to become the dominant force in electricity generation, accounting for an impressive 89.34% share by 2050. To mitigate the spatial mismatch between power load and resource allocation, the development of new transmission pathways and the expansion of the “power transmission from west to east” initiative are paramount. Furthermore, the implementation of a carbon-reducing power system offers significant potential for conserving water resources and alleviating water stress. These insights provide invaluable guidance for decision makers seeking to optimize multi-regional electric power systems for both water efficiency and low-carbon outcomes while simultaneously promoting the adoption of renewable energy sources and fostering synergistic development across regions.

Fermentation of olive pulp by Limosilactobacillus fermentumNCU001464: physicochemical properties, biological activity and bioactive phenols

SummaryOlives, which are rich in bioactive compounds, are processed into beverages in China. We investigated the effect of fermentation by Limosilactobacillus fermentum NCU001464 on the physicochemical characteristics, biological activities and phenolic compounds of olive pulp. After fermentation for 48 h, pH and individual sugar content of olive pulp decreased. Lm. fermentum NCU001464 fermentation enhanced the hydroxyl radical scavenging activity and the inhibitory effect against xanthine oxidase (XO) of olive pulp. Total phenol content was not significantly different between olive pulp fermented for 0 and 48 h. However, the fermented olive phenol extract had a lower IC50 value than the unfermented phenol extract. Fluorescence spectroscopy results revealed that the olive phenol extract had a stronger XO inhibitory effect after fermentation. The dominant binding forces between olive phenols and XO were hydrogen bonds and van der Waals forces. There were 31 different phenolic compounds between the unfermented and fermented extracts.

Understanding Inconsistencies in Thermohydraulic Characteristics Between Experimental and Numerical Data for DI Water Flow Through a Rectangular Microchannel

Abstract Facing discrepancies between numerical simulation, experimental measurement, and theory is common in studies of fluid flow and heat transfer in microchannels. The cause of these discrepancies is often linked to the transition from the macroscale to the microscale, where the flow dynamics might be expected to deviate due to possible changes in dominant forces. In this work, an attempt is made to achieve agreement between experiment, numerical simulation, and theoretical description within the usual framework of laminar flow theory. For this purpose, the pressure drop, friction factor, and Poiseuille number under isothermal conditions and the temperature profile, heat transfer coefficient, Nusselt number, and thermal performance index under diabatic conditions (heating power of 10 W) in a heat sink with a stainless steel microchannel with a hydraulic diameter of 850 μm were investigated numerically and experimentally for mass flow rates between 1 and 68 gmin−1. The source of inconsistencies in pressure drop characteristics is found to be linked to the geometrical details of the utilized microchannel, for example, the design of inlet/outlet manifolds, the artifacts of manufacturing technique, and other features of the experimental test rig. For the heat transfer characteristics, it is identified that an appropriate estimation of the outer boundary condition for the numerical simulation remains the crucial challenge to obtain a reasonable agreement. The paper provides a detailed overview of how to account for these details to mitigate the discrepancies and to establish a handshake between experiments, numerical simulations, and theory.

Knowledge Mapping for Fire Risk Assessment: A Scientometric Analysis Based on VOSviewer and CiteSpace

Fire risk assessment is a crucial step in effective fire control, playing an important role in reducing fire losses. It has remained a significant topic in the field of fire safety. To explore the research hotspots and frontier trends in fire risk assessment and to understand its macroscopic development trajectory, a sample of 1596 papers from 1976 to 2023, extracted from the Web of Science (WoS) database, was utilized to create a knowledge map. The study employed bibliometric methods, visual analysis, and content analysis to uncover the research pulse and hotspots in the field, offering insights into its future development. The findings indicate that research in fire risk assessment has demonstrated continuous growth over the past 50 years. China and the United States are the dominant research forces in the field, while India and Australia show potential as new drivers for development. Expert groups have formed in this field, with intra-institutional cooperation being the primary focus, while inter-institutional collaboration remains limited. The research outcomes exhibit multidisciplinary crossovers, exerting a significant impact on various disciplinary domains. The research hotspots primarily revolve around investigating fire and explosion accidents, assessing the vulnerability of fire subjects, and identifying potential fire hazards. The application of artificial intelligence technology is identified as a pivotal tool for future development. However, to achieve substantial progress, it is important to enhance the importance accorded to fire risk assessment, foster multinational and cross-institutional cooperation, and prioritize research innovation.

POLICY CAPACITY AND E-GOVERNANCE: ASSESSMENT OF THE E-GOVERNMENT SERVICES OF VALENCIA CITY, BUKIDNON

The rise of electronic governance has become a dominant force shaping the future of government. This study focuses on assessing the policy capacity of e-government services in LGU-Valencia City. It explores the competencies and capabilities of the local government in delivering basic e-government services, identifies strengths and weaknesses in their implementation, and provides recommendations for improvement. The findings highlight the analytical, operational, and political capacity of LGU-Valencia City in terms of e-governance, emphasizing essential competencies such as human resources, data management, policy support, technical expertise, and training. Operational capacity themes include organizational structure, financial and infrastructure resources, technology and information systems, and policy framework. Political capacity themes encompass leadership, citizen participation, stakeholder engagement, transparency, and intergovernmental relations. The study also reveals the presence of government-to-government (G2G) e-services in Valencia City, emphasizing collaborations and partnerships among agencies. Strengths and weaknesses of different e-government types (G2B, G2C, G2E) are identified, along with challenges in citizen acceptance and the positive impact of e-governance on businesses and employee relationships. Overall, the study concludes that LGU- Valencia City demonstrates policy capacity and readiness for digital innovation. The study suggests future researchers adopt a multi- method approach, compare policy capacity across LGUs, engage stakeholders and endusers, and emphasize capacity-building. These recommendations aim to contribute to improving governance and public services by conducting relevant and rigorous studies on policy capacity and e-governance in LGUs.

Molecular basis of phenotypic plasticity in a marine ciliate.

Phenotypic plasticity, which involves phenotypic transformation in the absence of genetic change, may serve as a strategy for organisms to survive in complex and highly fluctuating environments. However, its reaction norm, molecular basis, and evolution remain unclear in most organisms, especially microbial eukaryotes. In this study, we explored these questions by investigating the reaction norm, regulation, and evolution of phenotypic plasticity in the cosmopolitan marine free-living ciliates Glauconema spp., which undergo significant phenotypic changes in response to food shortages. This study led to the de novo assembly of macronuclear genomes using long-read sequencing, identified hundreds of differentially expressed genes associated with phenotypic plasticity in different life stages, validated the function of two of these genes, and revealed that the reaction norm of body shape in response to food density follows a power-law distribution. Purifying selection may be the dominant evolutionary force acting on the genes associated with phenotypic plasticity, and the overall data support the hypothesis that phenotypic plasticity is a trait maintained by natural selection. This study provides novel insight into the developmental genetics of phenotypic plasticity in non-model unicellular eukaryotes and sheds light on the complexity and long evolutionary history of this important survival strategy.

The (surprise) return of development policy space in the multilateral trading system: what the WTO Appellate Body blockage means for the developmental state

Since the establishment of the World Trade Organization (WTO) – which led to a dramatic expansion in the scope of global trade rules and made those rules legally binding on states – scholars have highlighted the constraints it has imposed on development policy space. By prohibiting many of the standard tools of the developmental state, the WTO’s rules have been seen as ‘kicking away the ladder’ for developing countries, preventing them from using the trade and industrial policies needed to catch up with more advanced economies. However, since 2019, the US has disabled the WTO’s enforcement mechanism by blocking judicial appointments to the Appellate Body. As a result, this article shows the trade and development landscape has now changed fundamentally: WTO rules – once a powerful constraint on development policy space – are no longer legally enforceable. The article analyzes two recent landmark disputes – Indonesian nickel export restrictions and Indian export subsidies provided through special economic zones – in which developing countries have successfully blocked WTO panel rulings that would force them to repeal developmentalist policies. Ironically, given that the US was originally the dominant force behind the WTO’s anti-developmentalist rules and its binding dispute settlement system, one important consequence of the US Appellate Body blockage has been the re-emergence of development policy space in the multilateral trading system.

Quantifying microplastic dispersion due to density effects

An experimental study was conducted on how polymer density affects the transport and fate of microplastics in aquatic flows. For the first time, polypropylene (PP), polyethylene (PE), polymethyl methacrylate (PMMA), polyetheretherketone (PEEK), and polyvinyl chloride (PVC) were chemically stained and tested using solute transport techniques and velocities found among rivers in the natural environment (0.016 – 0.361 m/s). The movement of 3D-polymers with densities ranging from 0.9 – 1.4 g/cm³ was quantified in a laboratory flume scaled to simulate open-channel flows in fluvial systems. Except for PP, in most conditions microplastics exhibited similar transport characteristics to solutes regardless of density and established solute transport models were successfully implemented to predict their transport and fate. Mass recoveries and ADE routing model demonstrated microplastic deposition and resuspension was associated with polymer density below critical velocity thresholds ≤ 0.1 m/s. When density becomes the dominant force at these slower velocities, concentrations of denser than water microplastics will be momentarily or permanently deposited in channel beds and microplastics follow the classical Shields sediment transport methodology. This data is the first to provide microplastic suspension and deposition thresholds based on river velocity and polymer density, making a key contribution to research predicting microplastic fate and organismal exposure.