Asynchronous Changes Research Articles

Asynchronous changes of hydrogen sulfide and its generating enzymes in most tissues with the aging process.

Aging is an inevitable and irreversible biological process that gradually heightens the risks of various diseases and death. As a newly discovered endogenous gasotransmitter, hydrogen sulfide (H2S) has been identified to exert multiple beneficial impacts on the regulation of aging and age-related pathologies. This study was aimed at systematically exploring the relationship between asynchronous aging processes and H2S concentrations in various tissues of aging mice. Samples of plasma and 13 tissues were collected from four cross-sectional age groups (3, 6, 12 and 18 months of age) covering the lifespan of male C57BL/6J mice. The H2S concentration was quantified by a reported liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with monobromobimane derivatization. Additionally, the expressions of cystathionine γ-lyase (CSE), cystathionine β-synthase and 3-mercaptopyruvate sulfurtransferase, in those tissues were analyzed by Western blotting. We discovered that the H2S concentrations decreased asynchronously with the aging process in plasma, heart, liver, kidney, spleen, subcutaneous fat and brown fat and increased in brain and lung. At least one of the three H2S-generating enzymes expressions was compensatorily up-regulated with the aging process in most tissues, among which the up-regulation of CSE was the most prominent.

Population asynchrony within and between trophic levels have contrasting effects on consumer community stability in asubtropical lake.

Clarifying the effects of biodiversity on ecosystem stability in the context of global environmental change is crucial for maintaining ecosystem functions and services. Asynchronous changes between trophic levels over time (i.e. trophic community asynchrony) are expected to increase trophic mismatch and alter trophic interactions, which may consequently alter ecosystem stability. However, previous studies have often highlighted the stabilising mechanism of population asynchrony within a single trophic level, while rarely examining the mechanism of trophic community asynchrony between consumers and their food resources. In this study, we analysed the effects of population asynchrony within and between trophic levels on community stability under the disturbances of climate warming, fishery decline and de-eutrophication, based on an 18-year monthly monitoring dataset of 137 phytoplankton and 91 zooplankton in a subtropical lake. Our results showed that species diversity promoted community stability mainly by increasing population asynchrony both for phytoplankton and zooplankton. Trophic community asynchrony had a significant negative effect on zooplankton community stability rather than that of phytoplankton, which supports the match-mismatch hypothesis that trophic mismatch has negative effects on consumers. Furthermore, the results of the structural equation models showed that warming and top-down effects may simultaneously alter community stability through population dynamics processes within and between trophic levels, whereas nutrients act on community stability mainly through the processes within trophic levels. Moreover, we found that rising water temperature decreased trophic community asynchrony, which may challenge the prevailing idea that climate warming increases the trophic mismatch between primary producers and consumers. Overall, our study provides the first evidence that population and trophic community asynchrony have contrasting effects on consumer community stability, which offers a valuable insight for addressing global environmental change.

Asynchronous characteristics of Feammox and iron reduction from paddy soils in Southern China

Recently, the newly discovered anaerobic ammonium oxidation coupled with iron reduction (i.e., Feammox) has been proven to be a widespread nitrogen (N) loss pathway in ecosystems and has an essential contribution to gaseous N loss in paddy soil. However, the mechanism of iron-nitrogen coupling transformation and the role of iron-reducing bacteria (IRB) in Feammox were poorly understood. This study investigated the Feammox and iron reduction changes and microbial community evolution in a long-term anaerobic incubation by 15N isotope labeling combined with molecular biological techniques. The average rates of Feammox and iron reduction during the whole incubation were 0.25 ± 0.04 μg N g−1 d−1 and 40.58 ± 3.28 μg Fe g−1 d−1, respectively. High iron oxide content increased the Feammox rate, but decreased the proportion of Feammox–N2 in three Feammox pathways. RBG-13-54-9, Brevundimonas, and Pelomonas played a vital role in the evolution of microbial communities. The characteristics of asynchronous changes between Feammox and iron reduction were found through long-term incubation. IRB might not be the key species directly driving Feammox, and it is necessary to reevaluate the role of IRB in Feammox process.

Spatiotemporal Variation of the Cretaceous‐Eocene Arc Magmatism in Lhasa‐Tengchong Terrane

AbstractIt was recognized that two magmatic belts in the Lhasa‐Tengchong terrane formed due to the Mesozoic‐Cenozoic Tethyan evolution. Still, their spatiotemporal variations of magmatic flare‐ups/lulls are rarely discussed. Here we use the new U‐Pb and Lu‐Hf isotopic data of captured zircons and a comprehensive data set to show that the flare‐up of northern magmatic belt has peak ages of 110 Ma in central and northern Lhasa and 120 Ma in eastern Tengchong, possibly related to the tectonic transition from Meso‐ and Neo‐Tethyan double subduction to Neo‐Tethyan single subduction. For the southern magmatic belt, the flare‐ups at 100–85 Ma and 65–45 Ma in eastern southern Lhasa indicate obvious juvenile crustal growth, while flare‐ups at 75–45 Ma in western southern Lhasa and Tengchong record ancient crustal reworking. Such flare‐up variations in the southern magmatic belt possibly resulted from asynchronous changes in the Neo‐Tethyan slab dip.

Thermal evolution and strengthening mechanisms in LPBF CoCrFeMnNi alloy: New insights on correlation between microstructure and mechanics with LAGBs

The complex microstructure with multi-scale features in CoCrFeMnNi alloy, prepared by laser powder bed fusion (LPBF), significantly improves strength while maintaining sufficient ductility, but it theoretically has thermal instability. The thermal stability of these multi-scale microstructure features and their impact on mechanical properties are systematically analyzed by means of annealing. The multi-scale microstructure features are characterized by asynchronous changes as temperature increases, leading to non-uniform changes in mechanical properties, notably at 400 °C and 1000 °C. The entangled dislocations and segregated elements at cellular substructure boundaries exhibit limited thermal stability, beginning to disintegrate at 400 °C and complete by 1000 °C. In contrast, both low-angle and high-angle grain boundaries maintain their effectiveness up to 1000 °C. The strengthening effect of low-angle grain boundaries (LAGBs), distinct from dislocation strengthening, has been quantitatively assessed through experimental methods, revealing that LAGBs contribute 17.13% to the overall strengthening, effective up to 1000 °C. However, dislocation strengthening contributes only 25.87%，marking a notable deviation from the traditionally estimated 50% dislocation contribution. This study provides a new perspective on understanding the relationship between the microstructure and mechanical properties of alloys prepared by LPBF.

Asynchronous Holocene human population changes in north and south China as related to animal resource utilization

During the Holocene, rich Neolithic and Bronze cultures developed in the middle and lower reaches of Yellow River valley (north China) and Yangtze River valley (south China), making them the core areas of past human activities. Thus, it is important to reveal the process and driving mechanism of regional population change. Agriculture development has always been taken as the key driver of population changes, and current studies mainly focus on the role that cultivation played, however, it is still unclear if animal resource utilization also contributed to regional population changes. Here, the spatiotemporal changes of population and domestic animal utilization levels in north and south China from 10 to 2 ka BP have been reconstructed based on 27,935 archaeological sites and faunal remains data from 94 sites, respectively, and the change in potential wild animal resources has been simulated by the Minimum Terrestrial Resource Model (MTRM). The results show asynchronous changes of population occurred in north and south China during 10–2 ka BP, which were correlated with regional domestic and potential wild animal resource utilization. In north China, more significant population growth corresponded to a greater increase of domestic animal ratios and a sharp decline of potential wild animal resources after 8 ka BP. In south China, less significant population growth was accompanied by a slower increase of domestic animal ratios and stable variations of potential wild animal resources. This research suggests that different changes of potential wild animal resources in north and south China contributed to spatial variations in survival pressure, utilization level of domestic animals, and population growth, which was further determined by asynchronous changes of precipitation in the two regions. This study explains the impact of climate changes on population from a new perspective.

Positive Lynden-Bell derivative as a ticket to the bar trap?

ABSTRACT We have translated the results of N-body simulations of one barred model into the language of action variables and frequencies. Using this language, we analysed the behaviour of all orbits in the model on a large time-scale at the stage of a mature bar. We show that the orbits join the bar while preserving their adiabatic invariant, which takes into account the three-dimensional structure of the orbits. This allows us to apply the concept of the Lynden-Bell derivative for each of these orbits and trace how the sign of the derivative changes; i.e. how asynchronous changes in angular momentum Lz and orbital precession rate Ωpr (normal orbital mode) change to synchronous (abnormal mode). The transition to the abnormal mode occurs when Ωpr reaches the angular velocity of the pattern Ωp, after which the orbit becomes stuck in the bar trap. All this happens against the background of secular changes in actions (Lz decreases, JR and Jz increase). At the same time, corotating particles near two stable Lagrange points are also subject to secular changes in their actions. They increase Lz and drift to the periphery, shifting corotation outwards. We also show that a change in the orbital mode from normal to abnormal and the trapping of orbits in a bar are possible only when the bar speed decreases with time, regardless of what is causing the bar to slow down. Our findings clarify and expand the picture of bar formation and evolution in numerical models.

Drought offsets the vegetation greenness-induced gross primary productivity from 1982 to 2018 in China

Recent studies have shown that climate stress may cause asynchronous changes between greenness and productivity, but the mechanism how greenness and productivity respond to drought remains unclear. The significant greening of vegetation in China has attracted worldwide attention; nevertheless, it is unclear whether large-scale greening will translate into productivity in the context of recent droughts. In this study, we used the vegetation index dataset to extract long-term trends in vegetation greenness and productivity from 1982 to 2018, and then chose the multi-scale Standardized Precipitation Evapotranspiration Index (SPEI) index to measure how vegetation greenness and productivity change in response to drought. The results show that significant vegetation greening did not cause a simultaneous increase in productivity during 1982–2018. Vegetation greenness and productivity trends were relatively consistent before 2000 and diverged after 2000, especially during the prolonged drought of 2000–2009. The opposite trend between greenness and productivity in humid ecosystems during drought periods mainly caused this trend difference. In humid ecosystems, short-term drought promotes vegetation greening, while long-term drought has no significant impact on greenness. However, the inhibitory effect of drought on productivity deepens with an increase in drought duration. Therefore, prolonged droughts offset vegetation greenness-induced gross primary productivity. We also found that prolonged drought causes a significant decrease in greenness but has little effect on productivity in arid ecosystems, possibly because vegetation productivity is more sensitive to soil water than atmospheric drought. Our results highlight the complexity of vegetation growth in the context of climate change. Furthermore, it is crucial to pay attention to the impact of climate stress on regional carbon sequestration functions, considering the significant carbon sink potential of forest areas in southern China.

Tabular Two-Dimensional Correlation Analysis for Multifaceted Characterization Data.

We propose tabular two-dimensional correlation spectroscopy analysis for extracting features from multifaceted characterization data, essential for understanding material properties. This method visualizes similarities and phase lags in structural parameter changes through heatmaps, combining hierarchical clustering and asynchronous correlations. We applied the proposed method to data sets of carbon nanotube (CNT) films annealed at various temperatures and revealed the complexity of their hierarchical structures, which include elements such as voids, bundles, and amorphous carbon. Our analysis addresses the challenge of attempting to understand the sequence of structural changes, especially in multifaceted characterization data where 11 structural parameters derived from eight characterization methods interact with complex behavior. The results show how phase lags (asynchronous changes from stimuli), and parameter similarities can illuminate the sequence of structural changes in materials, providing insights into phenomena such as the removal of amorphous carbon and graphitization in annealed CNTs. This approach is beneficial even with limited data and holds promise for a wide range of material analyses, demonstrating its potential in elucidating complex material behaviors and properties.

Asynchronous changes in terrestrial near-surface wind speed among regions across China from 1973 to 2017

Understanding the characteristics and causes of asynchronous changes in near-surface wind speed (NSWS) improves the ability of climate projection, but yet to be comprehended are the asynchronous features in NSWS and possible causes over China. In this study, the asynchronous variations in NSWS among regions are considerable across China. The non-synchronization of variations in intra-annual NSWS was manifested in the amplitudes and periods of NSWS. The amplitudes and periods of intra-annual NSWS among regions were in the ranges of 0.08–0.20 m s−1 and 0.24–0.32 years, respectively. The intra-annual changes in NSWS in different regions were influenced by different large–scale ocean–atmosphere circulations (LOACs). The non-synchronization of variations in interannual NSWS was also manifested in the amplitudes and periods of NSWS, and the strongest and weakest interannual variations in NSWS occurred over northeast and northwest China. The interannual variations in NSWS could be induced by El Niño–Southern Oscillation (ENSO). At intra-annual and interannual scales, LOACs mainly controlled the changes in the phase of NSWS, which could not be responsible for the amplitudes of NSWS. The interdecadal NSWS also showed regional differences, and it mainly exhibited an increase after the 1990s in all regions except for South China. The interdecadal changes in NSWS among regions were also dominated by LOACs, which contributed reached 50.0% to the NSWS changes. Furthermore, the LOACs dominated not only the changes in the phase of interdecadal NSWS but also the changes in amplitudes of interdecadal NSWS.

Signed expressions spotting and recognition in an assistive technology system

An algorithm for processing the continuous stream of incoming video data to detect and recognize signed expressions is proposed. The aim is to improve an assistive technology system. The method is based on the dynamic flow of expression models between a repository of inactive models and pools of active and completed models. When modeling signed expressions, so-called visemes are used. These are units smaller than words - the equivalent of phonemes known from speech recognition. Visemes are extracted by clustering descriptors of the holistic skeletons. The sequential-simultaneous nature of gestures is considered, and the modeling is carried out in four parallel channels related to the position and shape of both hands. The conditions for activation, deactivation, and recognition of the model as completed are formulated, assuming asynchronous changes in individual channels. The method is successfully tested on a demanding dataset recorded by potential users.

Fluctuating Wind Load Properties on the Surface of Inverted Umbrella-Shaped Membrane Structure Group

In the ABL wind tunnel, three inverted umbrella-shaped membrane structure groups were subjected to simultaneous pressure measurement model test. Time series of the fluctuating wind pressure were collected from 24 different wind angles. Upon examining the correlation coefficient of the fluctuating wind pressure between the upper and lower surfaces at the same pressure tap, it was discovered that the fluctuating wind pressure of the upwind roof exhibited asynchronous changes, which is a characteristic of a negative correlation area and has detrimental effects on the structure’s wind resistance. The local areas with non-Gaussian properties were evaluated by analyzing the probability density function of representative pressure taps. The mechanism behind non-Gaussian wind pressure was elucidated through considerations of the central limit theorem and spatial correlation of fluctuating wind pressure. This study introduces a quantitative classification criterion for identifying the non-Gaussian distribution area of fluctuating wind pressure, setting the threshold at an 80% cumulative probability for both skewness and kurtosis. The analysis showed that the steady airflow of the structure corresponds to the Gaussian distribution area, while the non-Gaussian distribution area is primarily concentrated at the front edge of the upwind roof and the rear edge of the downwind roof. To ascertain the peak factor for the non-Gaussian distribution, the improved peak factor method was utilized, providing insights into the range of peak factor in the non-Gaussian distribution area of this particular roof configuration. This information serves as a foundation for the wind resistance design of this structure.

Characterization of Puberty in an Australian Population-Based Cohort Study

PurposeCurrent knowledge of the characteristics of puberty beyond age at menarche and thelarche is limited, particularly within population-based cohorts. Secular trends and concerns of the health effects of early puberty reinforce the value of contemporary studies characterizing the timing, tempo, duration, and synchronicity of puberty. MethodsThe Childhood to Adolescence Transition Study is a unique Australian cohort of individuals followed annually from late childhood to late adolescence, with up to eight assessments of pubertal stage from 9 to 19 years of age (N = 1,183; 636 females). At each assessment, females reported their Tanner Stage of breast and pubic hair development, while males reported on genital/pubic hair development. Nonlinear mixed-effects models characterized pubertal trajectories and were used to derive each individual’s estimates of timing, tempo, and synchronicity. Parametric survival models were used to estimate the overall duration of puberty. ResultsTiming of mid-puberty (Tanner Stage 3) ranged from 12.5 to 13.5 years, with females developing approximately 6 months before males. Pubertal tempo (at mid-puberty) was similar across sex (between half and one Tanner Stage per year), but the overall duration of puberty was slightly shorter in males. Most females exhibited asynchronous changes of breast and pubic hair development. DiscussionEstimates of pubertal timing and tempo are consistent with reports of cohorts from two or more decades ago, suggesting stabilization of certain pubertal characteristics in predominantly White populations. However, our understanding of the duration of puberty and individual differences in pubertal characteristics (e.g., synchronicity of physical changes) remains limited.

Hydroclimate changes since the last glacial maximum from sedimentary biomarkers in a crater lake in the Great Khingan Mountains, Northeast China

The scarcity of well-dated, highly temporally resolved, paleoclimate records since the last glacial maximum (LGM) in Northeast China limits our understanding of past climatic variations and the prediction of future hydrological changes in the context of anthropogenic global warming. A high-resolution n-alkane record covering the past ∼25 kyr was retrieved from Lake Tuofengling, a hydrologically closed crater lake in the central Great Khingan Mountains. The sediments contained a suite of mid- and long-chain n-alkanes with a strong odd-to even-carbon number predominance. The relative proportion of mid-to long-chain n-alkane homologues (Paq) was proposed to evaluate the input of submerged/floating plants into lake sediments relative to that from emergent/terrestrial plants, which could be a useful indicator of lake level in lacustrine settings. The Paq proxy demonstrated that lake level increased stably from the shallowest level during the LGM to a maximum depth at 7.5–3.0 cal ka BP, with a minor decreasing trend during the late Holocene. The asynchronous changes in effective moisture in the East Asian summer monsoon (EASM) region since the LGM might be directly or indirectly mediated by the shift in the rainfall belt, the position and intensity of the Western Pacific Subtropical High and Okhotsk High at different timescales. Our study provides new insights into climatic evolution in Northeast China, where the main climate pattern may not always be similar to the typical EASM pattern.

Insights into asynchronous changes of cell wall polymers accumulated in different cell types during conifer xylem differentiation

An improved understanding of the events involved in cell wall polymers deposition during xylem development could provide new scientific ways for molecular regulation and biomass utilization. Axial and radial cells are spatially heterogeneous and have highly cross-correlated developmental behavior, whereas the deposition of corresponding cell wall polymers during xylem differentiation is less studied. To clarify our hypothesis that cell wall polymers of two cell types accumulated asynchronously, we performed hierarchical visualization, including label-free in situ spectral imaging of different polymer compositions during the development of Pinus bungeana. In axial tracheids, the deposition of cellulose and glucomannan was observed on earlier stages of secondary wall thickening than that of xylan and lignin, while xylan distribution was strongly related to spatial distribution of lignin during differentiation. The content of lignin and polysaccharides increased by over 130 % and 60 % respectively when the S3 layer was formed, compared to the S2 stage. In ray cells, the deposition of crystalline cellulose, xylan, and lignin was generally lagged compared to that in corresponding axial tracheids, although the process followed a similar order. The concentration of lignin and polysaccharides in ray cells was only approximately 50 % of that in the axial tracheids during secondary wall thickening.

Numerical investigation of the synchronous and asynchronous changes of ignition timing in a double spark plugs direct injection rotary engine

Numerical investigation of the synchronous and asynchronous changes of ignition timing in a double spark plugs direct injection rotary engine

Comparison of the dynamics of DNA damage in blood leukocytes and survival of mice after total body irradiation with Bragg peak carbon ions or x-rays

This study has determined a survival rate of mice irradiated with accelerated carbon ions (450 MeV/nucleon) in the Bragg peak or X-ray at a dose of 6.5 Gy, using the comet assay. Levels of DNA damage (%TDNA) in blood leukocytes from mice were measured 1 day before, 1-23 days after exposure to carbon ions and 1-28 days after exposure to X-ray radiation at the same dose. According to survival and % TDNA parameters, it was found that a damaging effect of carbon ions is greater than that of X-rays and substantial variations in % TDNA, which occur in individual animals, could appear to cause individual differences in the development of genome instability in the long term. It is assumed that a higher % TDNA in leukocytes after carbon ion exposure compared to that of X-rays, a wide range of variations and asynchronous changes in individuals in the post-irradiation period are associated with the induction of clustered DNA damages and mitochondrial dysfunction, and are also due to genetic and epigenetic factors. The results obtained point to the need to assess the state of blood leukocytes in animals with a heterogeneous genetic background using the comet assay before irradiation in order to form a group with similar %TDNA values. The revealed differences in individual laboratory animals require further study in order to improve animal models in the light of the development of personalized biomedicine.

Millennial Variability in Intermediate Ocean Circulation and Indian Monsoonal Weathering Inputs During the Last Deglaciation and Holocene

AbstractThe relationship between ocean circulation and monsoon systems over orbital to sub‐millennial timescales is a crucial but poorly constrained component of the climate system. Here, using foraminiferal and detrital neodymium (Nd) isotope records from the intermediate‐depth northern Indian Ocean, we provide new evidence revealing that both monsoon‐driven weathering inputs and water mass advection from the Southern Ocean influenced past seawater Nd isotope changes in this region. Our results suggest that Indian Summer Monsoon weakening coincided with enhanced northward Antarctic Intermediate Water (AAIW) advection during the last deglaciation, reflecting a strong interhemispheric coupling. In contrast, the Early Holocene was characterized by enhanced monsoon strength but persistently strong AAIW inflow, indicating a relationship in the opposite sense. These differing interhemispheric relationships indicate asynchronous changes in the global atmosphere—ocean—climate system, and may represent a previously unrecognized component of the ocean‐atmosphere reorganization during the deglacial to Holocene transition.

Two-Dimensional Clustering of Spectral Changes for the Interpretation of Raman Hyperspectra.

Two-dimensional correlation spectroscopy (2D-COS) is a technique that permits the examination of synchronous and asynchronous changes present in hyperspectral data. It produces two-dimensional correlation coefficient maps that represent the mutually correlated changes occurring at all Raman wavenumbers during an implemented perturbation. To focus our analysis on clusters of wavenumbers that tend to change together, we apply a k-means clustering to the wavenumber profiles in the perturbation domain decomposition of the two-dimensional correlation coefficient map. These profiles (or trends) reflect peak intensity changes as a function of the perturbation. We then plot the co-occurrences of cluster members two-dimensionally in a manner analogous to a two-dimensional correlation coefficient map. Because wavenumber profiles are clustered based on their similarity, two-dimensional cluster member spectra reveal which Raman peaks change in a similar manner, rather than how much they are correlated. Furthermore, clustering produces a discrete partitioning of the wavenumbers, thus a two-dimensional cluster member spectrum exhibits a discrete presentation of related Raman peaks as opposed to the more continuous representations in a two-dimensional correlation coefficient map. We demonstrate first the basic principles of the technique with the aid of synthetic data. We then apply it to Raman spectra obtained from a polystyrene perchlorate model system followed by Raman spectra from mammalian cells fixed with different percentages of methanol. Both data sets were designed to produce differential changes in sample components. In both cases, all the peaks pertaining to a given component should then change in a similar manner. We observed that component-based profile clustering did occur for polystyrene and perchlorate in the model system and lipids, nucleic acids, and proteins in the mammalian cell example. This confirmed that the method can translate to "real world" samples. We contrast these results with two-dimensional correlation spectroscopy results. To supplement interpretation, we present the cluster-segmented mean spectrum of the hyperspectral data. Overall, this technique is expected to be a valuable adjunct to two-dimensional correlation spectroscopy to further facilitate hyperspectral data interpretation and analysis.

Variations in the nutrient concentration and composition in Liaodong Bay under long-term human activities

This paper analyzed the long-term variations in nutrients in Liaodong Bay and their potential influencing factors based on historical data from 1978 to 2019. Under the influence of both human activities and natural changes, the concentration of DIN increased approximately 4-fold from the end of the 1990s to the mid-2010s, while DIP and DSi concentrations decreased from the beginning to the end of the 1980s and have since increased again. Asynchronous changes in nutrient levels have led to changes in the nutrient composition, which has caused a series of ecological effects. The total phytoplankton abundance decreased from the 1980s to the end of the 1990s and then increased again. Additionally, the phytoplankton composition shifted from a diatom-dominated to a dinoflagellate-dominated system, and the dominant species of zooplankton changed. Harmful algal blooms (HABs) rarely occurred before the 1980s but have frequently occurred since the end of the 1990s.