Station Spacing Research Articles

Teleseismic virtual-source reverse time migration of upper crustal structures in the Three Gorges region, China

Summary The Three Gorges (TG) in central China is an earthquake prone region that lacks active-source seismic surveys, hence requiring high-resolution passive seismic imaging to reveal crustal structures in detail. While teleseismic virtual-source reflection (TVR) profiling is effective for imaging gently dipping upper crustal structures, it is unsuitable for mapping steep structures beneath rugged topography in the TG region. Here we develop a teleseismic virtual-source reverse time migration (TV-RTM) to improve the imaging of steep structures. Synthetic tests are conducted to demonstrate the validity and resolution of the TV-RTM method. To mitigate the imaging inaccuracy due to sparse station spacing, we interpolate direct-arrival waveforms to achieve a doubling of the minimally required station spacing from 2 km to 4 km. The TV-RTM images of the upper crustal structure beneath a 2D array in the TG region reveal significant fold and thrust structures that correlate well with the surface geology and tectonic framework. The resolution of the images is assessed using 2D and 3D synthetic models with the station and source geometry of field data. The TV-RTM method provides a new passive seismic solution for studying upper crustal structures in regions that lack active-source seismic data.

Quantifying Creep on the Laohushan Fault Using Dense Continuous GNSS

The interseismic behavior of faults (whether they are locked or creeping) and their quantitative kinematic constraints are critical for assessing the seismic hazards of faults and their surrounding areas. Currently, the creep of the eastern segment of the Laohushan Fault in the Haiyuan Fault Zone at the northeastern margin of the Tibetan Plateau, as revealed by InSAR observations, lacks confirmation from other observational methods, particularly high-precision GNSS studies. In this study, we utilized nearly seven years of observation data from a dense GNSS continuous monitoring profile (with a minimum station spacing of 2 km) that crosses the eastern segment of the Laohushan Fault. This dataset was integrated with GNSS data from regional continuous stations, such as those from the Crustal Movement Observation Network of China, and multiple campaign measurements to calculate GNSS baseline change time series across the Laohushan Fault and to obtain a high spatial resolution horizontal crustal velocity field for the region. A comprehensive analysis of this primary dataset indicates that the Laohushan Fault is currently experiencing left-lateral creep, characterized by a partially locked shallow segment and a deeper locked segment. The fault creep is predominantly concentrated in the shallow crustal region, within a depth range of 0–5.7 ± 3.4 km, exhibiting a creep rate of 1.5 ± 0.7 mm/yr. Conversely, at depths of 5.7 ± 3.4 km to 16.8 ± 4.2 km, the fault remains locked, with a loading rate of 3.9 ± 1.1 mm/yr. The shallow creep is primarily confined within 3 km on either side of the fault. Over the nearly seven-year observation period, the creep movement within approximately 5 km of the fault’s near field has shown no significant time-dependent variation, instead demonstrating a steady-state behavior. This steady-state creep appears unaffected by postseismic effects from historical large earthquakes in the adjacent region, although the deeper (far-field) tectonic deformation of the Laohushan Fault may have been influenced by the postseismic effects of the 1920 Haiyuan M8.5 earthquake.

Managing impressions: performance and identity in police leadership in the pandemic

ABSTRACT Critical leadership scholars have long recognised leadership as performative and reveal the symbolic, presentational and ritual aspects of leadership practice as meaning-making. This perspective, however, is neglected in mainstream understanding of police leadership. Drawing on Goffman’s dramaturgical framework and a qualitative study of policing leaders in the UK, this paper explores performativity and police leadership in the context of the COVID-19 pandemic. Removed from occupational symbols of the police station and performing leadership work exclusively in the home environment, the findings show that police leaders used the uniform as part of a strategy of impression management to construct front and back stage regions in the domestic sphere. In frontstage settings, the uniform was used to represent occupational authority and reinforce a sense of shared, professional identity and purpose, despite the physical separation between leaders and their staff. Alongside this, police leaders constructed and maintained backstage spaces for preparatory and reparative work, even within the home-working setting. The findings challenge traditional conceptualisations of the backstage as physical, boundaried space of the police station and instead reveal backstage space as fluid, dynamic and imagined. As police constabularies consider the impact of remote-working practices on the police workplace, the preservation of backstage spaces for police leaders during the COVID-19 pandemic reveals the value and necessity this backstage work in police leadership.

Extracting fault-zone structures using the virtual seismometer method: from theoretical to synthetic test

Summary Rocks near a fault plane are commonly damaged by multiple earthquake ruptures, forming damage zones. The damage zone is important structures controlling various properties of a fault, yet its fine scale (tens to hundreds of meters) structure is difficult to resolve with surface seismic observations. We propose to use earthquakes that occur at depth within a fault zone as virtual seismometers (VSs) and use surface observations to extract Green's function (GFs) between VS pairs (VSGFs) . This method resembles that of ambient noise tomography and the retrieved VSGFs are related to the structures between event pairs. In this study, we develop the theory about how to extract VSGFs using surface stations deployed across a fault zone. Firstly, we use a half-space model and Fresnel zone analysis to determine the upper and lower limits of the GF frequency band, which is controlled by the station spacing and aperture of a given seismic array. Then, for VS in a fault zone, we demonstrate that the VSGF can be retrieved by linear seismic arrays deployed across the fault, and that the VSGF is equivalent to waves emitted simultaneously from an array of mirror sources of one event and received by the other. Secondly, the half-space result is directly adopted to determine the corresponding frequency band in the damage zone situation. Thirdly, we analyze different combinations of VS pair geometry and conclude that a relatively larger VS distance (much larger than the damage zone width) is more effective to recover damage zone structures for the available frequency bands. In this situation, VSGFs are trapped waves, that is represented by the interference of mirror sources. In such a case, the trapped waves are equivalent to surface waves, which have dispersion features to extract damage zone structures. Finally, we adopt the VSGF method to the Ridgecrest earthquake aftershock monitoring array and use a profile of aftershocks to extract 6 pairs of VSGFs. The spatial variation of VSGFs may reflect the depth-dependent variation of damaged zone. Our analysis shows a promising direction to use VSGFs to extract spatial variations of fault damaged zones.

User-needs-oriented shared DC charging resources optimal configuration and operation for improving EV penetration in old residential communities

The charging limitation of electric vehicles (EVs) in old residential communities (ORCs) derived from insufficient electricity capacity and parking spaces significantly impacts residents' quality of life and impedes urban sustainability. Considering economic and social factors, ORCs are likely to persist worldwide for the foreseeable future. To tackle these challenges, this paper proposes the scheme of shared DC fast charging stations to address the EV charging issues in ORCs. Specific methods involve minimizing the charging station spaces and charging infrastructure investment, while optimizing the photovoltaic (PV) and energy storage capacity. Additionally, a coordinated charging strategy based on dynamic price is designed to guide users in choosing the initial charging time, enhancing EV charging infrastructure utilization and EV penetration. This work is predominantly driven by human needs, integrating surveys on human behavior related to charging station locations and charging times. This case study is based on a real-life ORC in Shenzhen, China. By utilizing the proposed dynamic-pricing coordinated charging strategy tailored to the station capacity, the maximum EV penetration rate is to be achieved with satisfying EV charging demand. Furthermore, the implementation of dynamic pricing effectively guides users to adjust charging behavior, achieving the peak-shaving and valley-filling performance of load curves.

Geoelectrical Evaluation of Contamination in and around Ori-Ile Battery Wastes Dumpsite in Ibadan, Southwestern Nigeria

Geoelectrical surveys involving vertical electrical sounding (VES) and 2D resistivity imaging were integrated to assess subsurface contamination by heavy metals in and around Orile Battery Waste Dumpsite, Kumapayi in Ibadan, Southwestern Nigeria. The objectives are to determine the lateral and vertical variations of resistivity/conductivity in and around the dumpsite, determine the nature and thickness of the overburden, determine the depth to bedrock, and delineate subsurface zones of anomalously high conductivity/low resistivity which may have resulted from contamination by heavy metals. Thirty-three VES stations were occupied using the Schlumberger electrode array with electrode spacing (AB/2) varied from 1 m to 100 m. The 2D resistivity survey was carried out along six East–West trending traverses established across and around the dumpsite using the Dipole-Dipole electrode array with station spacing of 10 m and expansion factor, n=1-5. The VES data were quantitatively interpreted using initial partial curve matching technique and 1D forward modelling while the dipole-dipole data were interpreted using 2D inversion procedures. The geoelctric sections delineated three layers comprising topsoil with layer resistivity ranging from 18 Ωm to 264 Ωm and thickness varying from 0.4 m to 1.4 m, weathered layer with resistivity and thickness ranging from 1 Ωm to 219 Ωm and 0.6 m to 9.4 m respectively, and weathered/fractured/fresh bedrock with resistivity ranging from 132 Ωm and 6500 Ωm. The 2D inverted resistivity sections revealed anomalous resistivity lows suggesting contamination at depths ranging from 5 m to 10 m beneath the traverses. The contamination zones are characterized by resistivity values less than 10 Ωm. The study revealed that the soil beneath the study area has been contaminated by the battery wastes. The suspected fractures and relatively shallow water table observed in the study area may have predisposed the groundwater to contamination which could constitute serious health risk to the inhabitants. It is recommended that geochemical analysis for heavy metals be conducted on the soil and groundwater from wells in the study area to assess the level of contamination.

Spurious Rayleigh-wave apparent anisotropy near major structural boundaries: a numerical and theoretical investigation

SUMMARY The recent developments in array-based surface-wave tomography have made it possible to directly measure apparent phase velocities through wave front tracking. While directionally dependent measurements have been used to infer intrinsic $2\psi $ azimuthal anisotropy (with a 180° periodicity), a few studies have also demonstrated strong but spurious $1\psi $ azimuthal anisotropy (360° periodicity) near major structure boundaries particularly for long period surface waves. In such observations, Rayleigh waves propagating in the direction perpendicular to the boundary from the slow to the fast side persistently show a higher apparent velocity compared to waves propagating in the opposite direction. In this study, we conduct numerical and theoretical investigations to explore the effect of scattering on the apparent Rayleigh-wave phase velocity measurement. Using 2-D spectral-element numerical wavefield simulations, we first reproduce the observation that waves propagating in opposite directions show different apparent phase velocities when passing through a major velocity contrast. Based on mode coupling theory and the locked mode approximation, we then investigate the effect of the scattered fundamental-mode Rayleigh wave and body waves interfering with the incident Rayleigh wave separately. We show that scattered fundamental-mode Rayleigh waves, while dominating the scattered wavefield, mostly cause short wavelength apparent phase velocity variations that could only be studied if the station spacing is less than about one tenth of the surface wave wavelength. Scattered body waves, on the other hand, cause longer wavelength velocity variations that correspond to the existing real data observations. Because of the sensitivity of the $1\psi $ apparent anisotropy to velocity contrasts, incorporating such measurements in surface wave tomography could improve the resolution and sharpen the structural boundaries of the inverted model.

A dual-base station constraint method to improve deformation monitoring precision consistency in strip regions

The precision of deformation monitoring with Global Navigation Satellite System (GNSS) relative positioning is significantly influenced by the distance between the monitoring and base stations. In long strip regions, the considerable differences in station spacing lead to inconsistent monitoring precision among multiple stations. This presents a challenge to accurately model and predict the deformation pattern. To tackle this issue, this paper introduces a novel dual-base station constraint method. This method integrates the baseline length constraint between two base stations into the conventional relative positioning model. The formulae of the proposed method are first derived in detail. Then the data collected at eight monitoring stations in two strip regions of 6 km and 8 km over a 28-day period are used to validate the effectiveness of the proposed method. The quantitative analysis of monitoring precision consistency indicators and hypothesis testing on the correlation between monitoring precision and station spacing are conducted. The results show that: (1) median values of the East, North, and Up consistency indicators are reduced from 2.14, 1.41, and 1.83 to 0.91, 0.67, and 0.55 and from 1.85, 1.85, and 2.32 to 0.69, 1.00, and 0.87, respectively, indicating monitoring precision consistency improvement for two case studies; (2) the absolute values of the correlation coefficients between monitoring precision and station spacing decrease from 0.99, 0.94, and 0.98 to 0.09, 0.36, and 0.32. Using the t-test with a significant level of 0.01, it is demonstrated that there is no significant correlation between monitoring precision and station spacing when employing the proposed method.

Multi‐Scale Seismic Imaging of the Ridgecrest, CA, Region With Waveform Inversion of Regional and Dense Array Data

AbstractWe develop an inversion procedure for deriving multi‐scale velocity models with waveform inversions of earthquake and ambient noise data at multi‐frequency bands recorded by regional and dense sensor configurations. The method is applied for the area around the 2019 Ridgecrest earthquake rupture zones, utilizing data recorded by regional stations and dense 2D and 1D arrays with station spacings of ∼5 km and ∼100 m, respectively. Starting with regional Vp, Vs models and locations of Ridgecrest aftershocks, the velocity models and event locations are improved iteratively by inversions of waveforms recorded by regional stations and the 2D array, using a minimum spectral element size of ∼600 m. Waveforms from local events recorded by dense 1D arrays across the M7.1 rupture zone with frequencies of up to 10 Hz are used to resolve small‐scale features of the rupture zone and shallow crust with a local spectral element size of 80 m. The refined models provide self‐consistent descriptions of the rupture zone and the shallow crust embedded in the regional structures. The results reveal pronounced low Vs and high Vp/Vs in the M6.4 and M7.1 rupture zones coinciding with concentrations of seismicity, and also around the Garlock fault and in several local basins. We also observe clear velocity contrasts across the Garlock fault with polarity reversals along strike and with depth. The obtained multi‐scale velocity models can be used to improve derivations of earthquake source properties, simulations of dynamic ruptures and ground motions, and the understanding of fault and tectonic processes in the region.

Crustal and uppermost mantle structures of the North American Midcontinent Rift revealed by joint full-waveform inversion of ambient-noise data and teleseismic P waves

The Midcontinent Rift (MCR), hosting several world-class ore deposits, is the fossil remnant of a massive Mesoproterozoic rifting event (1.1 Ga) that did not lead to the formation of an ocean basin. To better understand the lithospheric processes associated with the rifting stage and its subsequent failure, we developed a novel full-waveform joint inversion method using ambient noise data and teleseismic P waves for this seismically inactive region. We apply this approach to three years (2011-2013) of seismic recordings from the Superior Province Rifting EarthScope Experiment (SPREE) (~12 km average station spacing) and the USArray Transportable Array (~70 km average station spacing), and obtain a new 3D high-resolution Vs model down to 100 km depth, as well as Vp and density models down to 60 km depth. The model shows major velocity anomalies in agreement with previous seismic studies for the western arm of the MCR. In particular, we observe high density (2.8-3.0 g/cm3), Vp (6.3-6.5 km/s), and Vs (3.6-3.7 km/s) structures in the shallow upper crust within the rift, likely associated with volcanic rocks. Similar to a previously identified underplated layer, we also observe extensive normal-to-high Vs (3.8-4.2 km/s) along the whole rift axis and Vp (6.8-7.5 km/s) beneath the northern segment of the rift within the lower crust. However, the Vs and Vp values are lower than average for typical underplated materials. We suggest that this underplated layer may represent a combination of different intrusive rock types (e.g., gabbro, anorthosite) developed during magma differentiation processes, or contamination of the mafic magma by surrounding crustal material, or intrusions of sills.

A feasibility study of Boree Salt body mapping in the Adavale Basin using passive seismic data

Hydrogen plays a pivotal role in the global energy transition and may require underground storage. So far salt cavern storage is the only proven technology for underground hydrogen storage. The Boree Salt in the Adavale Basin, mostly at depths from 1 to 2.5 km and up to 550 m thick, consists predominantly of halite and is deemed suitable for hydrogen storage. However, current maps are inadequate. Recently passive seismic data (ambient noise) have received much interest for subsurface imaging. The main signal from passive data is surface waves (usually below 2 Hz). The capability of surface waves for the Boree Salt body mapping is examined. Parameters of seismic sensor spacing, the dominant frequencies of the surface waves, and data noise levels are all considered. It is demonstrated that surface waves from ambient noise can map the Boree Salt bodies with a survey distance of ~40 km. Between frequencies of 0.12 and 0.25 Hz, results from the latter have better resolution because of a shorter wavelength. Moving to higher frequencies of 0.5 and 1 Hz, however, the resolution becomes worse, because the depth sensitivity of surface waves moves to the shallower part of the model with increasing frequencies, rendering them incapable of effectively probing the targeted depths. For signal/noise ratio above five, station spacing can be as large as 1 km without compromising quality. Therefore, cost-effective and environmentally friendly passive seismic data can be a good alternative to the traditional active-source data for deep salt body imaging.

Research on the Supply of Shared Bicycles in Subway Hub Stations-Taking the Subway Station of Zhengzhou People 's Hospital as an Example

In recent years, with the rapid development of shared bicycles, it has played a great role in alleviating urban traffic pressure and facilitating residents to go out to a certain extent. However, while solving the problem of the last kilometer of travel, the uneven distribution of shared bicycles in subway hub stations is becoming more and more serious, which has a certain impact on the quality of residents ' travel. This paper takes the supply of shared bicycles in urban subway hub stations as the research object, and observes and summarizes the characteristics of slow traffic flow near the entrances and exits of subway hub stations in the morning and evening peak hours. On the premise of ensuring the right of way for pedestrians, the supply and demand of shared bicycles in the subway hub station and the configuration of shared bicycles in the surrounding space of the subway hub station are comprehensively considered, and the supply of shared bicycles is predicted by the estimation model and the field data of the subway hub station are investigated, taking the subway station of Zhengzhou People 's Hospital as an example to carry out field research and predict the actual demand and supply of shared bicycles in the subway hub. Finally, the problems existing in the research on the supply of shared bicycles in metro hub stations and possible future research directions are summarized.

SItomo – A toolbox for splitting intensity tomography and application in the Eastern Alps

The tomographic inversion of shear wave splitting data for upper mantle anisotropy has been a longstanding challenge. This is due to the ray-based approximation of classical approaches and the near-vertical incidence of the core-mantle converted phases such as SKS that are often used. Recent developments include the calculation of finite-frequency sensitivity kernels for SKS splitting intensity observations, which allows us to accurately take into account the sensitivity to anisotropic structure with depth. A requirement of this tomographic technique is a dense station spacing, which results in overlapping sensitivity kernels at depth and allows for the localization of anisotropic structure. This is satisfied by a growing number of temporary seismic deployments, which motivates the desire to image anisotropic complexities with depth. Here, we introduce and make available a toolbox for the MATLAB environment that facilitates the application of finite-frequency splitting intensity tomography to dense seismic arrays. Our implementation includes several key features, including: 1) A forward calculation of splitting intensities and sensitivity kernels for a complex anisotropic model space. 2) Consideration of the dominant period of the wave, allowing for multiple-frequency analysis, as well as the incoming wave’s non-vertical incidence. 3) The inversion can be based on a classical gradient descent, on a form of the conjugate gradient method known as the BFGS algorithm, or on a gradient-informed stochastic reversible jump algorithm, allowing for a data-driven parametrization of the model space. 4) Importing splitting intensity measurements from waveforms processed in SplitRacer allows for fast pre-processing of large data sets due to its fully automatic design. To illustrate our method, we present both synthetic tests and an application to real data. We apply our inversion procedure to data from the Swath-D network, which densely covers the transition of the Central to the Eastern Alps. Previous studies showed evidence for an abrupt lateral change of layered seismic anisotropy that had been attributed to an opening for channeled asthenospheric flow. Using an SKS splitting intensity tomography approach, we can confirm previous inferences while providing additional constraints on the distribution of anisotropy laterally and with depth.

Evaluate Human Perception of the Built Environment in the Metro Station Area

Transit-oriented development (TOD) has become a dominant form of spatial planning and land use in large cities internationally. As the intersections of urban space and rail transportation, metro station areas play a key public service function in the lives of city residents. Based on the “5D” index and Node-Place theory in the metro station area, current research on the built environment in metro station areas focuses on improving the economic and transportation efficiency while neglecting public perception of the construction of station space. Sentiments, as an important part of the individual’s perception, are closely related to the built environment. Therefore, this study takes 187 metro stations within the fifth ring road of Beijing, China, as an example and extracts public sentiment information from social media data using a wide range of natural language processing techniques to quantitatively analyze the distribution of the public’s sentiment characteristics (including intensity, polarity, and category) in the metro station area and deeply explores the spatial correlation with the distribution of the objective built environment elements. The study shows that influenced by the spatial design of the metro station, density, land use functions, etc., the sentiment intensity of the station area within the Fifth Ring Road of Beijing is “strong in the east and weak in the west, strong in the north and weak in the south”, and the sentiment polarity has the characteristic of gradually negative from inside to outside in a circular pattern. Synthesizing the sentiment perception in the metro station area, our study further divided the Beijing metro station area into four major categories and eight specific subtypes.

A comparative study on walking accessibility of high-speed railway station areas in China and Japan based on analytic hierarchy process -- Beijing station and Osaka station as examples

ABSTRACT To capture the factors influencing and measurements of pedestrian accessibility to high-speed rail station areas, ensure the balance between the transportation function and place performance of high-speed railway station areas, the correlation factors and laws of pedestrian space characteristics of high-speed railway station areas under different development modes are studied through the comparison of typical high-speed railway station areas in China and Japan. Combining the circle law and hierarchical analysis method, we establish a walking accessibility index system, construct a walking accessibility evaluation model for the high-speed rail station area, measure the degree of walking accessibility in the high-speed rail station area, and analyze the influence mechanism of different walking space components on the walking accessibility of the high-speed rail station area circle. The results indicate that: 1) Osaka Station space is much more walkable than Beijing Station in all circles; 2) The spatial development within the Beijing Station Station Circle is uneven, and the degree of pedestrian accessibility decreases as the circle’s extent increases; 3)Different station spaces have their own advantages and disadvantages in terms of the distribution of public facilities and amenities, roadway attributes, pedestrian path characteristics, depending on their respective national conditions and station development patterns.

Ocular complaints and diagnoses in spaceflight.

The NASA human system risk board (HSRB) has long focused on trauma and acute medical illness as a key contributor to high level in-flight medical risk. However, ocular issues, trauma, and complaints during spaceflight are poorly characterized. In a retrospective case series, the NASA data from the life sciences data archieve (LSDA) and the lifetime surveillance of astronaught health (LSAH) was queried for eye related complaints and conditions in spaceflight across international space station (ISS) missions and space shuttle (STS) missions. The ISS dataset included missions from the year 2000 to 2020, and the STS dataset included missions from 1981 to 2011. Data were reviewed and segmented into categories of ocular complaints. 135 STS missions and 63 ISS missions were included in this analysis. Ocular events were only noted across 83 STS missions (61.5%) and 41 ISS missions (65.1%). Overall, the most common ocular complaints were eye irritation (n = 80, 33.1%), ocular foreign body or foreign body sensation (n = 55, 22.7%), dry eye syndromes (n = 38, 15.7%), epiphora or excessive tearing (n = 19, 7.85%). Of all ocular complaints or diagnoses, 9 (3.72%) were considered higher severity (keratitis, corneal ulcer, chemical exposure, and corneal abrasion). However, seemingly none required evacuation from mission. Improved depiction of ocular symptoms and diagnoses, and a more standard classification system and process to describe ocular symptoms, diagnoses, and treatments in space is crucial to provide more effective and comprehensive treatments.

Introducing fine grained energy consumption variables into a public passenger transport simulation in SUMO

Improving energy efficiency in public passenger transport is key to achieving sustainability goals. In many developing countries, public passenger transport relies heavily on fossil fuels, which necessitates a strong focus on reducing emissions from energy consumption. Surprisingly, few studies have addressed this issue in the context of daily operations, with most research focusing on operational and infrastructural changes. This paper aims to fill this gap by introducing detailed energy consumption variables into a public transport simulation model using SUMO, a tool known for its seamless integration with Python. The development of two Python scripts underpins this endeavour. The first script facilitates the automatic generation of scenarios, allowing the manipulation of parameters such as station spacing, line length, passenger capacity and waiting times, among others. The second script is dedicated to estimating energy consumption for each scenario. Together, these tools allow us to calculate average energy consumption for different scenarios and modes of public transport. As a result, they provide valuable insights for the formulation of public policies aimed at saving energy in different public transport environments and lay the foundation for the integration and development of intelligent transport systems and simulation-based digital twins.

ОСОБЕННОСТИ МИКРОБНОЙ КОЛОНИЗАЦИИ КОНСТРУКЦИОННЫХ МАТЕРИАЛОВ, ИСПОЛЬЗУЕМЫХ В КОСМИЧЕСКОЙ ТЕХНИКЕ, ПРИ ИХ МНОГОЛЕТНЕМ ЭКСПОНИРОВАНИИ В СРЕДЕ ОБИТАНИЯ МЕЖДУНАРОДНОЙ КОСМИЧЕСКОЙ СТАНЦИИ

The paper presents the results of studying quantitative dynamics, changes in composition and species diversity (Shannon diversity index, SDI) of the cultivable microbial community on samples of structural materials in the course of long-term exposure inside the International space station (space experiment Biorisk). It was found that the total number and species diversity of microorganisms changed in waves but the general trend was downward. In all, over the period of the experiment we detected, after cultivation in nutrient media, 20 bacterial species and 5 species of microscopic fungi grown on the samples of structural materials. Among bacteria, dominating species belonged to genus Bacillus, and species of the normal cutaneous and mucous microbiota belonged to genus Staphylococcus and Micrococcus. Genus Aspergillus and Penicillium dominated among fungi. Species diversity of the cultivable microbial community was maximal for textured glass and minimal for polyvinylchloride. SDI was 2.99 and 1.72 respectively. Also, these materials were populated by the largest (11) and least (5) numbers of cultivable microorganisms. The low microbial load on all types of materials after different periods of exposure suggests eco-safety of the ISS environment and effectiveness of the respective control measures.

From Experimental Animal to Companion: Astronaut`s Behavioural Health and Risk Management for Mars Exploration

Space science has been developed through past and current missions of the International Space Station (ISS) and Tiangong Space Station (TSS) in low Earth orbit and on the lunar surface. Numerous missions have used animals on test flights to better understand the physiological dangers of space flight for humans. A contemporary focus of space exploration is long-duration crewed travel to establish a Moon station and reach Mars. The astrotechnology of the human-less spaceflights (USA, Russia, ESA, UAE, China, and India) launched in 1965 (Mariner 4), has advanced enough to support the progressive colonisation of the Red Planet with investigating equipment (Perseverance rover, Ingenuity helicopter, Hope orbiter, Tianwen-1 orbiter, and Chinese lander-rover). Are humans, then, ready to explore for Mars soon? What are major hazards that still need to be solved? Can animals play a novel role for humans in deep space travel? While the five factors of altered gravity, radiation, confinement (isolation), distance from Earth, and unknown hostile environments have been analysed in the scientific field of space medicine, this paper explores the biological ripple effects of animal astronauts to mitigate risks for human astronauts. The countermeasures of the psychological well-being and space community security are determined considering the potential role of animals in reducing the emergence rate of behavioural health and performance decrements (loneliness, mental and emotional strain, fear, lethargy, lack of enthusiasm, and violence). This paper argues a new hypothesis that if the engineering aspects of animal (dog) support does not reduce the scientific capabilities, the cognitive policy of a �human-pet companionship� apart from the historically traditional pattern of �experimental animal� can benefit the mental, social, and physical resilience of the Martian astronauts during the return mission (2.5�3 years).

Simulation modeling as a means of forecasting passenger traffic at Moscow Metro transfer stations

The article substantiates the necessity of simulation modeling for passenger traffic processes at Moscow Metro stations. The study aims to develop a simulation model based on pedestrian flows to predict changes in their density and directions in the organization of the station space. The use of the method of structural analysis allowed to establish all the key objects of the studied processes and the links between them. Input parameters and process interaction rules are obtained using abstraction, synthesis, grouping, and statistical analysis techniques. Based on the results obtained, formal models of the behavior of each group of objects have been developed. A 3D twin model corresponding to the real research object was created to visualize the simulation model results and demonstrate the results of the scenario implementation. Moscow Metropolitan can use the results obtained for the operational management of flows at the stations and the modernization of their infrastructure.