Gravity Changes Research Articles

Lung diffusing capacity for nitric oxide in space: microgravity gas density interactions.

Introduction: During manned space exploration lung health is threatened by toxic planetary dust and radiation. Thus, tests such as lung diffusing capacity (DL) are likely be used in planetary habitats to monitor lung health. During a DL maneuver the rate of uptake of an inspired blood-soluble gas such as nitric oxide (NO) is determined (DLNO). The aim of this study was to investigate the influence of altered gravity and reduced atmospheric pressure on the test results, since the atmospheric pressure in a habitat on the moon or on Mars is planned to be lower than on Earth. Changes of gravity are known to alter the blood filling of the lungs which in turn may modify the rate of gas uptake into the blood, and changes of atmospheric pressure may alter the speed of gas transport in the gas phase. Methods: DLNO was determined in 11 subjects on the ground and in microgravity on the International Space Station. Experiments were performed at both normal (1.0atm absolute, ata) and reduced (0.7 ata) atmospheric pressures. Results: On the ground, DLNO did not differ between pressures, but in microgravity DLNO was increased by 9.8% (9.5) (mean [SD]) and 18.3% (15.8) at 1.0 and 0.7 ata respectively, compared to normal gravity, 1.0 ata. There was a significant interaction between pressure and gravity (p = 0.0135). Discussion: Estimates of the membrane (DmNO) and gas phase (DgNO) components of DLNO suggested that at normal gravity a reduced pressure led to opposing effects in convective and diffusive transport in the gas phase, with no net effect of pressure. In contrast, a DLNO increase with reduced pressure at microgravity is compatible with a substantial increase of DmNO partially offset by reduced DgNO, the latter being compatible with interstitial edema. In microgravity therefore, DmNO would be proportionally underestimated from DLNO. We also conclude that normal values for DL in anticipation of planetary exploration should be determined not only on the ground but also at the gravity and pressure conditions of a future planetary habitat.

ANALYSIS OF GRAVITY ON ALTITUDE CHANGES IN GRAVITY MICRO DATA USING POLYNOMIAL EQUATION APPROACH (CASE STUDIES OF MERAPI AND KELUD VOLCANOES)

Analysis of gravity changes to altitude changes from gravity measurements at Merapi Volcano and Kelud Volcano was carried out to determine the characteristics of the two mountains based on the gravity method. Merapi Volcano and Kelud Volcano are two very active mountains in Indonesia and have different physiography, especially at the top of Kelud there is a crater filled with water. Repeated gravity surveys will be useful for studying deformation in volcanoes and providing information about changes in subsurface mass. The gravity data on Merapi Volcano is secondary data from BPPTKG (Research and Development Center for Geological Disaster Technology), and data on Kelud Volcano is obtained from the 2019 data collection survey. Volcanic monitoring using the gravity method is carried out by observing changes in gravity with changes in altitude to study deformation in the volcano and providing information about changes in subsurface mass using a polynomial equation approach of to . The findings indicate that there was little variation in the gravity anomaly within Merapi Volcano between 2018 and 2019. The highest coefficient of determination, at 96%, was observed in the gravity anomaly data from inside the Kelud Volcano in 2019, after applying Bouguer corrections in the form of spherical effects. Additionally, the coefficients of the second and third order polynomials of the Merapi Volcano data had opposite signs to those of Kelud Volcano, suggesting that the internal source of the gravity anomaly within Merapi Volcano is distinct from that within Kelud Volcano.

The chemical neighborhood of cells in a diffusion-limited system.

Microorganisms follow us everywhere, and they will be essential to sustaining long-term human space exploration through applications such as vitamin synthesis, biomining, and more. Establishing a sustainable presence in space therefore requires that we better understand how stress due to the altered physical conditions of spaceflight affects our companion organisms. In microgravity environments such as orbital space stations, microorganisms likely experience the change in gravity primarily through changes in fluid mixing processes. Without sedimentation and density-driven convection, diffusion becomes the primary process governing the movement of growth substrates and wastes for microbial cells in suspension culture. Non-motile cells might therefore develop a substrate-deficient "zone of depletion" and experience stress due to starvation and/or waste build-up. This would in turn impact the concentration-dependent uptake rate of growth substrates and could be the cause of the altered growth rates previously observed in microorganisms in spaceflight and in ground-simulated microgravity. To better understand the extent of these concentration differences and their potential influence on substrate uptake rates, we used both an analytical solution and finite difference method to visualize concentration fields around individual cells. We modeled diffusion, using Fick's Second Law, and nutrient uptake, using Michaelis-Menten kinetics, and assessed how that distribution varies in systems with multiple cells and varied geometries. We determined the radius of the zone of depletion, within which cells had reduced the substrate concentration by 10%, to be 5.04 mm for an individual Escherichia coli cell in the conditions we simulated. However, we saw a synergistic effect with multiple cells near each other: multiple cells in close proximity decreased the surrounding concentration by almost 95% from the initial substrate concentration. Our calculations provide researchers an inside look at suspension culture behavior in the diffusion-limited environment of microgravity at the scale of individual cells.

Insights into the Magmatic Feeding System of the 2021 Eruption at Cumbre Vieja (La Palma, Canary Islands) Inferred from Gravity Data Modeling

This study used spatiotemporal land gravity data to investigate the 2021 eruption that occurred in the Cumbre Vieja volcano (La Palma, Canary Islands). First, we produced a density model by inverting the local gravity field using data collected in July 2005 and July 2021. This model revealed a low-density body beneath the western flank of the volcano that explains a highly fractured and altered structure related to the active hydrothermal system. Then, we retrieved changes in gravity and GNSS vertical displacements from repeated measurements made in a local network before (July 2021) and after (January 2022) the eruption. After correcting the vertical surface displacements, the gravity changes produced by mass variation during the eruptive process were used to build a forward model of the magmatic feeding system consisting of dikes and sills based on an initial model defined by the paths of the earthquake hypocenters preceding the eruption. Our study provides a final model of the magma plumbing system, which establishes a spatiotemporal framework tracing the path of magma ascent from the crust–mantle boundary to the surface from 11–19 September 2021, where the shallowest magma path was strongly influenced by the low-density body identified in the inversion process.

Human neural network activity reacts to gravity changes in vitro.

During spaceflight, humans experience a variety of physiological changes due to deviations from familiar earth conditions. Specifically, the lack of gravity is responsible for many effects observed in returning astronauts. These impairments can include structural as well as functional changes of the brain and a decline in cognitive performance. However, the underlying physiological mechanisms remain elusive. Alterations in neuronal activity play a central role in mental disorders and altered neuronal transmission may also lead to diminished human performance in space. Thus, understanding the influence of altered gravity at the cellular and network level is of high importance. Previous electrophysiological experiments using patch clamp techniques and calcium indicators have shown that neuronal activity is influenced by altered gravity. By using multi-electrode array (MEA) technology, we advanced the electrophysiological investigation covering single-cell to network level responses during exposure to decreased (micro-) or increased (hyper-) gravity conditions. We continuously recorded in real-time the spontaneous activity of human induced pluripotent stem cell (hiPSC)-derived neural networks in vitro. The MEA device was integrated into a custom-built environmental chamber to expose the system with neuronal cultures to up to 6 g of hypergravity on the Short-Arm Human Centrifuge at the DLR Cologne, Germany. The flexibility of the experimental hardware set-up facilitated additional MEA electrophysiology experiments under 4.7 s of high-quality microgravity (10-6 to 10-5 g) in the Bremen drop tower, Germany. Hypergravity led to significant changes in activity. During the microgravity phase, the mean action potential frequency across the neural networks was significantly enhanced, whereas different subgroups of neurons showed distinct behaviors, such as increased or decreased firing activity. Our data clearly demonstrate that gravity as an environmental stimulus triggers changes in neuronal activity. Neuronal networks especially reacted to acute changes in mechanical loading (hypergravity) or de-loading (microgravity). The current study clearly shows the gravity-dependent response of neuronal networks endorsing the importance of further investigations of neuronal activity and its adaptive responses to micro- and hypergravity. Our approach provided the basis for the identification of responsible mechanisms and the development of countermeasures with potential implications on manned space missions.

High-Precision Gravimetric Monitoring Provides Insights into Subsurface Processes

Summary Monitoring of time-lapse changes in gravity has been carried out for decades, and measurement repeatability with relative spring gravimeters has in recent years improved to 0.6–2 µGal (standard deviation) for area surveys. This is better than often cited vendor specification. Gravimeters based on other physical principles offer high absolute accuracy or improved time-lapse sensitivity. All these may open possibilities for monitoring smaller and deeper subsurface changes and over shorter time intervals, with applications in hydrocarbon and geothermal production, gas and CO2 storage, hydrology, volcanology and more. Survey design and data processing are integral parts of a program. Sensor redundancy and repeat measurements provide opportunities for in-situ calibrations. An example from a gas accumulation shows a reduction in gravity of about 3 µGal and subsidence of 5–6 mm over 8 years. Both signals are clearly above the noise level and are likely to have been caused by production from a neighbouring structure. The information can quantify the amount of reservoir pore pressure drop, size of gas cap expansion and vertical movements of the gas-liquid contact to a precision well below 1 m.

Effects of plant extract and wood on anatomical structure in ecological environment interaction

In this study, the impregnation of a 3% solution of a mixture of medicinal aromatic plant extract, borax, and ferula plant extract on wood of eastern spruce (Picea orientalis L. (Link)) and mahogany were carried out and the changes in the anatomical structure of the impregnated wood were determined. Through obtaining extracts of various medicinal aromatic plants (ferula) and dual treatment with borax, the anatomical properties of wood material were examined and the related adhesion scale was determined. The highest retention (retention) was in mahogany wood borax (1.86%), and the lowest retention was again in mahogany wood ferula extract (0.31%). Both wood types demonstrated improved outcomes in comparison to the control sample when the air-dry and fully-dry specific gravity changes were investigated. The maximum air-dried specific gravity value was found in mahogany at 3% borax and ferula + borax (0.56 g/cm3), and the lowest at 3% ferula and borax (0.37 g/cm3). Mahogany wood with 3% borax had the greatest full dry specific gravity value (0.54 g/cm3), and spruce wood with 3% ferula and ferula + borax had the lowest (0.35 g/cm3). There was no retention in the tracheid and trachea cells that perform the transmission function. Because the sapphire cells are the cells that act as storage, adhesion has occurred in these cells.

Microgravity and immune cells.

The microgravity environment experienced during spaceflight severely impaired immune system, making astronauts vulnerable to various diseases that seriously threaten the health of astronauts. Immune cells are exceptionally sensitive to changes in gravity and the microgravity environment can affect multiple aspects of immune cells through different mechanisms. Previous reports have mainly summarized the role of microgravity in the classification of innate and adaptive immune cells, lacking an overall grasp of the laws that microgravity effects on immune cells at different stages of their entire developmental process, such as differentiation, activation, metabolism, as well as function, which are discussed and concluded in this review. The possible molecular mechanisms are also analysed to provide a clear understanding of the specific role of microgravity in the whole development process of immune cells. Furthermore, the existing methods by which to reverse the damage of immune cells caused by microgravity, such as the use of polysaccharides, flavonoids, other natural immune cell activators etc. to target cell proliferation, apoptosis and impaired function are summarized. This review will provide not only new directions and ideas for the study of immune cell function in the microgravity environment, but also an important theoretical basis for the development of immunosuppression prevention and treatment drugs for spaceflight.

Gravity estimation of groundwater mass balance of sandy aquifers in the land subsidence-hit region of Yunlin County, Taiwan

Land subsidence will decrease the safety factor of bridges and structures. Many highways and railways constructed decades ago are experiencing damage due to continual land subsidence in several alluvial fans of Taiwan. Groundwater over-pumping for industrial and agricultural uses leads to severe (>3 cm/year) land subsidence in the middle to distal Choushui River Alluvial Fan (CRAF), the largest alluvial fan in Taiwan. The Taiwan High Speed Rail passes through CRAF and land subsidence is now a major concern. Replenishing groundwater with artificial recharge lakes is a potential solution to mitigate land subsidence impacts. Using gravimetry, we examined two undetermined regional unconfined aquifers (RUAs) in the land subsidence-hit region that could host potential artificial recharge lakes to replenish groundwater. We established seven absolute gravity sites and measured time-lapsed gravity values in Yunlin in southern CRAF in 2021, including five sites in the subsidence-hit region and over two unconfined aquifers in the proximal fan. A consistent pattern of residual gravity changes associated with water storage changes at all the gravity sites confirms the recharge potential of the two RUAs in the land subsidence-hit region. Here we estimated groundwater storage changes by residual gravity changes around gravity sites without using prior hydrology information such as groundwater levels and storage coefficients. Of all the gravity sites in the land subsidence-hit region, the most significant March-to-September residual gravity change (26.6 μgal) and vertical displacement (−4.2 cm) were observed at Siutan elementary school (STES). The estimated groundwater storage change around STES is significantly large to increase the water balance in Yunlin, despite the site's severe land subsidence in 2021. We used electrical resistivity imaging (ERI) to aid the identification of the RUA near STES and discussed a potential joint gravimetry-ERI study of the RUAs for subsidence-mitigation engineering works such as constructions of recharge lakes.

Progress and prospect of the time-varying gravity in earthquake prediction in the Chinese Mainland

This paper mainly introduces the application and progress of the time-varying gravity in earthquake research in the Chinese Mainland. Since the Xingtai earthquake in 1966, China has begun mobile gravity monitoring, trying to explore the relationship between gravity changes and seismic activities. The gravity changes before and after the Haicheng MS7.3 earthquake in 1975 and the Tangshan MS7.8 earthquake in 1976 were observed. In 1981, a high-precision metal spring gravimeter was introduced to carry out high-precision mobile gravity observation in the key earthquake monitoring areas in western Yunnan. The gravity anomaly changes near the epicenters of the Lijiang MS7.0 earthquakes in 1996 were observed. In 1998, a high-precision absolute gravity survey was introduced to carry out the overall scale gravity field monitoring in the Chinese Mainland, and the large-scale gravity change information before Wenchuan MS8.0 and Yutian MS7.3 earthquakes in 2008 was obtained, and the effective prediction opinions were given. After the Wenchuan MS8.0 earthquake in 2008, the integration of the national network and the regional network accelerated, forming the whole gravity observation network in the Chinese Mainland, which made a relatively successful medium-term prediction for a series of earthquakes with MS6.0 or above (such as Lushan MS7.0, Menyuan MS6.4, and Jiuzhaigou MS7.0) in recent years and played an important role in the study of the earthquake mechanism and earthquake prediction level in China. Finally, the existing problems in time-varying gravity monitoring in China are pointed out, and the prospect of earthquake research using time-varying gravity monitoring data is put forward.

Relationship between gravity change and Yangbi MS6.4 earthquake

Based on the relative and absolute gravity measurements in the southern South-North Seismic Belt since 2015, we analyzed the dynamic change of the regional gravity field and its relationship with the Yangbi MS6.4 earthquake that occurred on May 21, 2021. The results show that: 1) The regional gravity field changes are closely related to the Weixi-Qiaohou fault, which reflects the surface gravity field changes caused by the fault activity from 2015 to 2021; 2) The gravity field change related to the preparation of Yangbi earthquake has experienced the evolution process of " steady state - regional gravity anomaly - local gravity anomaly - four-quadrant distribution - large area positive anomaly - earthquake occurring in the reverse change process "; 3) The cumulative and differential change images of the gravity field show that there were significant gravity changes in the two years preceding the Yangbi earthquake, and the earthquake occurred in the high-gradient belt of gravity variation, the center of the four-quadrant, and close to the zero contour turn; 4) The dynamic evolution image of the gravity field can well reflect the precursory phenomena during the preparation for the Yangbi MS6.4 earthquake. Based on the anomaly change of mobile gravity, a certain degree of medium-term prediction was made before the Yangbi MS6.4 earthquake, especially the determination of strong earthquake location.

Effects of Variations in Earth’s Gravitational Force Fields on Climate Change

World climate continues to deteriorate at varying rates in spite of different anthropogenic mitigative and adaptive interventions. Conversely, the gravitational force fields of the sun and moon hold Earth in orbit, amongst others. Herein, we explore the impacts of changes in these gravitational fields on global climate and examine their influences on natural events, such as ocean tides, volcanoes, geomagnetic storms and movement of tectonic plates. Beyond reports on greenhouse effect and mass transport, we discuss the influence of gravity on tidal bulges, melting glaciers, condensable atmosphere and other events, such as El Niño and La Niña, and correlate their typically subtle impacts on climate worldwide with variations in Earth’s gravity. The intention is to highlight other causative factors implicated in climatic change without diminishing the contributions of greenhouse gasses and other factors, which are currently regarded, by specialists and lay-public alike, as the major culprits of climate change. We submit that the shifts in Earth’s gravitational fields to sustain equilibrium and remain in orbit can manifest as perturbations of atmospheric temperatures, pressures and air concentrations as well as volume changes and ion effects; in hydrological bodies, and are some of the non-anthropogenic agents driving changes in global climate. We surmise, therefore, that the influence of changes in gravity, albeit subtle, on climate change is significant. It is envisaged that highlighting these subtle agents of change would intensify efforts toward ameliorating and/or eliminating drastic and deleterious changes in climate as well as at embracing adaptive measures at local and international levels.

Understanding the role of starch sheath layer in graviception of Alternanthera philoxeroides: a biophysical and microscopical study.

Plants' ability to sense and respond to gravity is a unique and fundamental process. When a plant organ is tilted, it adjusts its growth orientation relative to gravity direction, which is achieved by a curvature of the organ. In higher, multicellular plants, it is thought that the relative directional change of gravity is detected by starch-filled organelles that occur inside specialized cells called statocytes, and this is followed by signal conversion from physical information to physiological information within the statocytes. The classic starch statolith hypothesis, i.e., the starch accumulating amyloplasts movement along the gravity vector within gravity-sensing cells (statocytes) is the probable trigger of subsequent intracellular signaling, is widely accepted. Acharya Jagadish Chandra Bose through his pioneering research had investigated whether the fundamental reaction of geocurvature is contractile or expansive and whether the geo-sensing cells are diffusedly distributed in the organ or are present in the form of a definite layer. In this backdrop, a microscopy based experimental study was undertaken to understand the distribution pattern of the gravisensing layer, along the length (node-node) of the model plant Alternanthera philoxeroides and to study the microrheological property of the mobile starch-filled statocytes following inclination-induced graviception in the stem of the model plant. The study indicated a prominent difference in the pattern of distribution of the gravisensing layer along the length of the model plant. The study also indicated that upon changing the orientation of the plant from vertical position to horizontal position there was a characteristic change in orientation of the mobile starch granules within the statocytes. In the present study for the analysis of the microscopic images of the stem tissue cross sections, a specialized and modified microscopic illumination setup was developed in the laboratory in order to enhance the resolution and contrast of the starch granules.

Coseismic Gravity Changes and Crustal Deformation Induced by the 2018 Fiji Deep-Focus Earthquake Observed by GRACE and GRACE-FO Satellites

Earthquakes at depths of ≥300 km are generally called deep-focus earthquakes. Only two deep-focus earthquakes with Mw 8.0 or more have occurred in this century—the 2013 Okhotsk earthquake (Mw 8.3) and the 2018 Fiji earthquake (Mw 8.2) on 19 August 2018. However, the 2018 Fiji earthquake was only reported on seismographs, and the related crustal deformations were not observed by the Global Navigation Satellite System because the observation network did not exist around the epicenter. This study analyzed the time series of gravity data observed by the Gravity Recovery And Climate Experiment (GRACE) and its successor, GRACE Follow-On, and detected the spatial distribution of coseismic gravity changes mainly due to crustal deformation by the 2018 Fiji earthquake. The results in this study were not consistent with the numerical calculation of gravity changes when using the fault parameters estimated by the data of seismic waves. Thus, numerical calculations were used to construct a uniform slip rectangle fault model to explain coseismic gravity changes and provide a spatial distribution map of crustal deformation. However, this fault model is only based on gravity changes; thus, new research combining satellite gravimetry and seismic wave data will be necessary in the future.

Decoupled Control of Grasp and Rotation Constraints During Prehension of Weightless Objects.

Gravity provides critical information for the adjustment of body movement or manipulation of the handheld object. Indeed, the changes in gravity modify the mechanical constraints of prehensile actions, which may be accompanied by the changes in control strategies. The current study examined the effect of the gravitational force of a handheld object on the control strategies for subactions of multidigit prehension. A total of eight subjects performed prehensile tasks while grasping and lifting the handle by about 250mm along the vertical direction. The experiment consisted of two conditions: lifting gravity-induced (1g) and weightless (0g) handheld objects. The weightless object condition was implemented utilizing a robot arm that produced a constant antigravitational force of the handle. The current analysis was limited to the two-dimensional grasping plane, and the notion of the virtual finger was employed to formulate the cause-effect chain of elemental variables during the prehensile action. The results of correlation analyses confirmed that decoupled organization of two subsets of mechanical variables was observed in both 1g and 0g conditions. While lifting the handle, the two subsets of variables were assumed to contribute to the grasping and rotational equilibrium, respectively. Notably, the normal forces of the thumb and virtual finger had strong positive correlations. In contrast, the normal forces had no significant relationship with the variables as to the moment of force. We conclude that the gravitational force had no detrimental effect on adjustments of the mechanical variables for the rotational action and its decoupling from the grasping equilibrium.

Gravity influence in one-dimensional blood flow modeling

One-dimensional blood flow model accuracy has been verified in many studies. The topic of this work is introducing gravity into a one-dimensional model. For this purpose, gravitational force was introduced into an existing model. To account for gravity, the boundary conditions also must be adjusted to reflect the body's adaptation. For this purpose, a method for calculating the arterial resistance of the terminal arteries during gravity changes has been developed and presented in this article. The technique is based on the idea that the human body reacts to changes in gravity in such a way as to preserve the volume of blood delivered to the organs. Experiments have shown that not only the pressure, but also the flux waveform and the pressure waveform change when the flow is preserved. The method of adjusting the boundary conditions is such that the flow almost does not change after applying the gravity, but it is possible to estimate the change in pressure dynamics. This methodology can be used to study the blood flow in different cases related to gravity.

GRACE time-variable gravity and its application to geoscience: Quantitative analysis of relevant literature

The Gravity Recovery and Climate Experiment (GRACE) is the most important gravity satellite to date in human history. Since its launch in 2002, GRACE time-varying gravity has had an unprecedented impact on earth science and has generated revolutionary changes. Because of natural phenomena such as climate warming, glacial melting, sea level rise, and earthquakes, earth science research has become an increasingly popular discipline in recent years. This article summarizes the importance of GRACE time-varying gravity, its application to geoscience, and its development. We analyzed the historical development and current status of GRACE time-varying gravity as well as research hotspots by searching the literature in the core collection databases of the China National Knowledge Infrastructure and the Web of Science over the past 20 years. The CiteSpace and VOSviewer software packages were applied with reference to the principle of literature metrology. Our investigation and analysis of characteristic indexes, such as the numbers of publications, co-occurrence of keywords, and co-citation of documents, uncovered the wide application and promotion of gravity satellites, especially GRACE time-varying gravity, in earth science. The results showed that the number of publications addressing GRACE data and time-varying gravity theory is increasing annually and that the USA, China, and Germany are the main producers. The Chinese Academy of Sciences, the National Aeronautics and Space Administration of the United States, and the Helmholtz Association of German Research Centres rank among the top three institutions in the world in terms of producing the most publications on this topic. We found that GRACE time-varying gravity plays unique roles in measuring changes in terrestrial water storage changes, ice and snow melting and sea level changes, and (co)seismic gravity changes, as well as in promoting other disciplines.

Rapid Downregulation of H3K4me3 Binding to Immunoregulatory Genes in Altered Gravity in Primary Human M1 Macrophages

The sensitivity of human immune system cells to gravity changes has been investigated in numerous studies. Human macrophages mediate innate and thus rapid immune defense on the one hand and activate T- and B-cell-based adaptive immune response on the other hand. In this process they finally act as immunoeffector cells, and are essential for tissue regeneration and remodeling. Recently, we demonstrated in the human Jurkat T cell line that genes are differentially regulated in cluster structures under altered gravity. In order to study an in vivo near system of immunologically relevant human cells under physically real microgravity, we performed parabolic flight experiments with primary human M1 macrophages under highly standardized conditions and performed chromatin immunoprecipitation DNA sequencing (ChIP-Seq) for whole-genome epigenetic detection of the DNA-binding loci of the main transcription complex RNA polymerase II and the transcription-associated epigenetic chromatin modification H3K4me3. We identified an overall downregulation of H3K4me3 binding loci in altered gravity, which were unequally distributed inter- and intrachromosomally throughout the genome. Three-quarters of all affected loci were located on the p arm of the chromosomes chr5, chr6, chr9, and chr19. The genomic distribution of the downregulated H3K4me3 loci corresponds to a substantial extent to immunoregulatory genes. In microgravity, analysis of RNA polymerase II binding showed increased binding to multiple loci at coding sequences but decreased binding to central noncoding regions. Detection of altered DNA binding of RNA polymerase II provided direct evidence that gravity changes can lead to altered transcription. Based on this study, we hypothesize that the rapid transcriptional response to changing gravitational forces is specifically encoded in the epigenetic organization of chromatin.

Design and optimization of the tripod flexure for a 2m lightweight mirror for space application.

In order to ensure optimal optical performance, primary mirror assembly must be impervious to environmental influences. These environmental influences include gravity, assembly error, and thermal change, under which external loads are imposed on the mirror. The external loads degrade the mirror surface accuracy and cause misalignment between mirrors. In this paper, a tripod flexure with a flexible hinge is designed to alleviate the influence of the external load on the surface accuracy of a 2m primary mirror. This structure can effectively release the rotational freedom, provide a certain translational flexibility, and yield high axial stiffness. The axial stiffness is used to increase the frequency of the primary mirror assembly. According to the fast optimization model, the derivation of close form compliance equations is developed to characterize the flexibility, and parameter optimization is done to achieve the maximum performance. Then a finite element analysis and test are used to verify the final design. The results show that the index requirements of the 2m primary mirror have been met.

Estimating the thermal effect in gPhoneX observations

Stationary relative gravimeters are used in variety of applications, mainly due to their high sampling rate which is more suitable for study of certain geodynamic effects than absolute gravimeters. Study of weak signals is almost exclusively in the domain of superconducting gravimeters, as they possess the highest accuracy and stability of all types of relative gravimeters. Possible alternative to superconducting gravimeters are portable earth tide metal spring gravimeters. Zero-length spring gravimeters (e.g. LCR instruments) are usually considered to be the most accurate mechanical spring gravimeters. However, compared to superconducting instruments they remain too unstable for long-term gravity monitoring. Main reason supporting this statement is related to instrument's sensitivity to temperature changes and temperature induced tilts. Gravity observations from the gPhoneX #108 gravimeter stationed at Hurbanovo gravimetric observatory were tested in order to confirm the correlation between the observed gravity changes and ambient temperature changes and provide a solution for correcting the gPhone data for influence of the ambient temperature changes. Paper also aims to serve as a guide for other operators to estimate a parameters required for the calculation of ambient temperature correction.