Cumulative Changes Research Articles

A QUANTUM LEAP? THE CASE FOR RADICAL INNOVATION

Incremental innovation has become the norm as the influence of business and management disciplines and functions have come to dominate research and practice—for example, standard processes for product development, design-thinking to improve existing user practices and superficial business model variations. Such incremental approaches to managing innovation have merit, and can result in significant cumulative changes over time. However, the way in which such incremental innovation is resourced, organised and managed is fundamentally different to that for radical innovation, which is critical to address more significant commercial and social challenges. The cases of new product development (NPD) and business model innovation (BMI) are examined to identify the challenges researchers and managers face. We argue that to acquire a deeper understanding of how radical innovation works, more ambitious cross-disciplinary research is needed, rather than the current direction of travel in the literature towards single discipline studies and standard processes that apply primarily to incremental commercial innovations.

PENENTUAN SENSITIVITAS YANG BERPENGARUH TERHADAP PRODUKSI RESERVOIR MULTILAYER SECARA COMMINGLE

Multilayer reservoirs are not uncommon in oil and gas fields. In optimizing production in multilayer reservoirs, commingle production is an option. When producing a multilayer reservoir, it is necessary to select a reservoir with suitable characteristics. More and more research in producing multilayer reservoirs by commingle is being carried out. Forchheimer conducted research on the effect of turbulence that occurs, especially in gas wells. This turbulence effect causes pressure disturbances from the reservoir into the well. When the reservoir is produced in commingle, how does gas turbulence affect the production. This research is devoted to the production of commingle wells that penetrate three layers of a multilayer dry gas reservoir by considering the turbulence that occurs. Then it is determined the possible sensitivity that has an effect using literature studies in the multilayer field and gas well field based on the cumulative changes in production that occur in each sensitivity.

Instability of High Liquid Limit Soil Slope for the Expressway Induced by Rainfall

The instability of high liquid limit soil slope is a common engineering problem in highway construction. This study focused on the slope at section K79 + 880 of the Guang-Le Expressway in Guangdong Province, China. In order to reduce the landslide and learn the mechanism of the high liquid limited soil slope, the effects of different rainfall intensities and rainfall time on the high liquid limit soil slope were studied by in-site monitoring and numerical simulation. According to the characteristics of the slope deformation and the monitoring data, the slope landslide is divided into three grades. Numerical simulation results show that the influence of rainfall intensity on the safety factor of high liquid limit soil slope is greater than that of rainfall time. At the slope top, the cumulative changes of Mises stress in Group B and Group C were −2.19 kPa and −2.91 kPa, respectively, and the cumulative decreases were −7.22% and −9.60%, respectively. At the slope bottom, the cumulative changes of Mises stress in Group B and Group C were −2.05 kPa and −4.32 kPa, respectively, and the cumulative decreases were −4.50% and −9.48%, respectively. With the increase of rainfall for 24 h, the safety factor of Group C decreased by an average of 0.0408, and with the increase of rainfall time, the safety factor increased, and the safety factor of 96 h of rainfall in Group C was 0.1249 lower than that of 24 h of rainfall. The greater the rainfall intensity, the greater the change of matrix suction at the top of the slope, and the more prone the top of the slope to shallow landslides. For the high liquid limit soil slope, slope instability phenomena such as surface flow collapse occur easily and have little impact on the deep sliding surface. The dimensionless displacement coefficient K is proposed to quantify the landslide displacement under different rainfall. A general method is proposed to measure the cumulative displacement of the K79 + 880 slope where the sensor is not placed.

Deformation Mechanics of Fuel Cell Gas Diffusion Layer: Cyclic Response and Constitutive Model

The deformation mechanics of a typical gas diffusion layer using experimental and advanced modelling technique is reported. The experimental cyclic response is observed similar to pseudo-elastic materials with highly nonlinear loading/unloading. The cyclic compressive mechanical response of gas diffusion layer (GDL) is modelled to be the outcome of cumulative changes in deformation kinematics of matrix and fiber fractions. The individual mechanisms necessitating the energy dissipation, residual strain, and stress softening during cyclic mechanical response are related to nonlinear hyperelastic matrix with the damage function and inelastic activation function at the interface of constituents. The model predicts highly nonlinear elastic loading, residual strain, hysteresis, and damage quotient associated with stress softening as a function of several cycles. The significant takeaway from this study is in terms of quantifying strength, inelastic nature of individual constituents. The proposed model is simulated for low-level altering stresses of up to twenty cycles. The results show the build-up of residual strains and hysteresis as a function of fuel cell clamping pressure.

High nitrogen addition after the application of sewage sludge compost decreased the bioavailability of heavy metals in soil

Nitrogen (N) fertilizer is highly significant in agricultural production, but long-term N addition causes changes in quality indicators, such as soil organic matter (SOM), thus affecting the absorption and accumulation of organic pollutants. Therefore, paying more attention to organic fertilizers in the development of green agriculture is necessary. However, the accumulation of heavy metals (HMs) contained in organic fertilizers (especially sewage sludge compost (SSC)) in the soil can cause environmental contamination, but how this cumulative reaction changes with the long-term N addition remains unclear. Here the SSC impact on the bioavailability of five typical HMs (cadmium–Cd, chromium–Cr, copper–Cu, lead–Pb and arsenic–As) in the soil-plant system before and after SSC application was demonstrated through a field study in soils with different application rates of 0, 100 and 300 kg N ha−1yr−1, respectively. Our results showed that SSC application increased the concentration of most HMs in soil profiles and plant systems (wheat roots and grains), but the accumulation rate of HMs and most bioaccumulation values (BAC–bioaccumulation coefficient and BCF–bioconcentration factor) in plant systems were both lower in high-N addition soil than that in the low-N group. Moreover, speciation distribution results further indicated that SSC application increased the LB (liable available form, including F1–water soluble, F2–ion exchangeable, and F3–bound to carbonates) form of HMs and decreased the PB (potentially available form, including F4–humic acids and F6–fraction bound to organic matter) form of HMs in high-N addition soil, respectively. Those results suggested that HM bioavailability in high-N addition soil was lower than that in low-N addition soil when applied with SSC. Overall, this study found that increasing soil N content can inhibit the bioavailability of HMs when applying SSC, providing suggestions for optimizing the trialability and risk assessment of SSC application.

Exploring Tourism Efficiency and Its Drivers to Understand the Backwardness of the Tourism Industry in Gansu, China.

Gansu Province is rich in tourism resources, and it is the hometown of the “copper galloping horse”, which is the logo of China’s tourism. However, the scale and revenues of tourism in Gansu province are still at a low level. This paper first evaluated the tourism efficiency of 14 cities and prefectures of Gansu Province in China from 2011 to 2019 using the super-slack-based measure (Super-SBM) and then investigated the internal driving mechanism of the efficiency change through the Global Malmquist-Luenberger (GML) index and its decomposition, and finally analyzed the external influencing elements of tourist efficiency by the Tobit model. The results revealed that the tourism efficiency of Gansu Province had increased rapidly during the study period, especially after 2016, the rising range increased. From 2011 to 2019, the cumulative changes in GML index, technological change (TC), and efficiency change (EC) of tourism efficiency in Gansu Province were 5.053, 4.145 and 1.160, respectively, indicating that the improvement of tourism efficiency in Gansu province is mainly due to technological progress. The regression results of the Tobit model show that the status of the tourism industry, trade openness, information level, and technological innovation level can significantly promote tourism efficiency in the province. At the same time, upgrading the industrial structure and the improvement of greening coverage inhibit tourism efficiency. However, the impact of the economic development level on the tourism efficiency of Gansu Province is not apparent. According to the research results, this paper puts forward corresponding suggestions to promote the development of tourism in Gansu Province. This study is crucial for hospitality, tourism, and policy sectors to understand the underlying factors and promote the healthy development of the tourism industry in Gansu Province.

Soil water and solute transport in an Andosol apple orchard including the dormancy period in a snowy cold region

Early spring corresponds to the snowmelt season in apple orchards of the northern hemisphere. This has a significant effect on the initial growth of shoots and flower buds of apple trees. Understanding the soil environment of the orchard during the non-growth period as monitored by farmers is important for managing year-round apple production. However, the details of mass transport, such as that of soil water and solute, during the non-growing season in the Andosols remain unclear. This study conducted soil environment monitoring in an Andosol apple orchard in Aomori Prefecture, Japan, during the non-growing season in winter to examine the year-round changes in the soil environment, using a field monitoring system that is necessary for understanding the soil environment. Volumetric water content, soil bulk electrical conductivity, and soil temperature were measured, and the cumulative changes in total soil moisture (ΣΔTSM) were calculated from the monitored volumetric water content. Results showed that although ΣΔTSM tended to increase (i.e., dry out) annually with periodicity, the variation was small compared to that of apple orchards with gravelly brown forest soil. These results could significantly influence fertilization management of apple orchard soil during the summer drought season and early spring when the roots of apple trees begin taking up nutrients. In particular, it was revealed that if sufficient nutrients remain in the soil pore water in early spring, the negative impact of excessive fertilization on the surrounding environment can be reduced. Therefore, this study constitutes an innovative step in the implementation of field monitoring system to understand the details of mass transport in the Andosol apple orchard soil.

Changes of vegetational cover and the induced impacts on hydrological processes under climate change for a high-diversity watershed of south China

Understanding the changes in hydrological process is a key subject for water resource management of a high-diversity watershed. In this paper, through an establishment of a SWAT-based model, the effects of climate change and its induced vegetation change on hydrological process were analyzed in the East River Basin. The model could well simulate the hydrological processes of the basin including surface runoff (SURQ), groundwater (GWQ), lateral flow (LATQ), total water yield (WYLD), actual evapotranspiration (ET), and groundwater recharge (PERC). Under the vegetation change induced by temperature increase, the effects of the vegetation change on hydrological process were larger than that of the temperature change. Under the vegetation change caused by the increase of temperature and precipitation, the vegetation change enhanced the effects of climate change on annual SURQ, LATQ, GWQ, WYLD, and PERC of the basin. Under spatial scale, when the temperature and precipitation changed simultaneously, the increase of precipitation could promote the increase of annual ET in sub-watersheds. Also, the annual SURQ, WYLD, GWQ and ET in western sub-watersheds were more sensitive to the cumulative changes of vegetation and climate. This work can provide useful information to decision makers in water resource management of watersheds.

Arctic roads and railways: social and environmental consequences of transport infrastructure in the circumpolar North

Land-based transport corridors and related infrastructure are increasingly extending into and across the Arctic in support of resource development and population growth, causing large-scale cumulative changes to northern socio-ecological systems. These changes include the increased mobility of people, goods and resources, and environmental impacts on landscapes and ecosystems as the human footprint reaches remote, unindustrialized regions. Arctic climate change is also generating new challenges for the construction and maintenance of these transport systems, requiring adaptive engineering solutions as well as community resilience. In this review article, we consider the complex entanglements between humans, the environment, and land transportation infrastructure in the North and illustrate these interrelations by way of seven case studies: the Baikal–Amur Mainline, Bovanenkovo Railway, Alaska–Canada Highway, Inuvik–Tuktoyatuk Highway, Alaska Railroad, Hudson Bay Railway, and proposed railways on Baffin Island, Canada. As new infrastructure is built and anticipated across the circumpolar North, there is an urgent need for an integrated socio-ecological approach to impact assessment. This would include full consideration of Indigenous knowledge and concerns, collaboration with local communities and user groups in assessment, planning and monitoring, and evaluation of alternative engineering designs to contend with the impacts of climate change in the decades ahead.

Ukraine war-induced sanctions against Russia: Consequences on transition economies

We analyze the spillovers of Western economic sanctions against Russia into twenty-seven transition economies of the former Soviet Union, and Central and Eastern Europe. These spillovers are measured in terms of their impact on bilateral trade and direct investments for the period of 2014–2018. We construct a new dataset to quantify each episode of Western/US sanctions against Russia. The gravity models of bilateral trade and direct investment are used and the data analysis is conducted using Poisson pseudo-maximum likelihood econometric technique. We estimate that the Western and U.S. sanctions against Russia spilled over into third-party small countries. These sanctions resulted in the significant decline of exports from transition economies, Russian imports to transition economies, and Russian direct investments to transition economies. Interestingly, the direct investments to Russia from transition economies sharply increased during the same period. The quantitative estimates of the spillovers suggest the following cumulative changes. Due to an imposed sanction type (e.g., against an individual, entity or sector) each episode of Western/U.S. sanction resulted in the decline of aforementioned indicators in the range of 10.9–30.5-million-dollar/5.6–16.9-million-dollar of exports from transition economies, 6.3–17.7-million-dollar/3.3–9.8-million-dollar of Russian imports to transition economies, and 3.4–9.4-million-dollar/1.7–5.2-million-dollar of Russian direct investments to transition economies. The direct investments to Russia from transition economies increased by 10.9–30.6-million-dollar/5.7–17-million-dollar, respectively.

Personality stability and change: A meta-analysis of longitudinal studies.

Past research syntheses provided evidence that personality traits are both stable and changeable throughout the life span. However, early meta-analytic estimates were constrained by a relatively small universe of longitudinal studies, many of which tracked personality traits in small samples over moderate time periods using measures that were only loosely related to contemporary trait models such as the Big Five. Since then, hundreds of new studies have emerged allowing for more precise estimates of personality trait stability and change across the life span. Here, we updated and extended previous research syntheses on personality trait development by synthesizing novel longitudinal data on rank-order stability (total k = 189, total N = 178,503) and mean-level change (total k = 276, N = 242,542) from studies published after January 1, 2005. Consistent with earlier meta-analytic findings, the rank-order stability of personality traits increased significantly throughout early life before reaching a plateau in young adulthood. These increases in stability coincide with mean-level changes in the direction of greater maturity. In contrast to previous findings, we found little evidence for increasing rank-order stabilities after Age 25. Moreover, cumulative mean-level trait changes across the life span were slightly smaller than previously estimated. Emotional stability, however, increased consistently and more substantially across the life span than previously found. Moderator analyses indicated that narrow facet-level and maladaptive trait measures were less stable than broader domain and adaptive trait measures. Overall, the present findings draw a more precise picture of the life span development of personality traits and highlight important gaps in the personality development literature. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

It all adds up…the impact of cumulative changes on safety and production

AbstractOn December 21, 1999, a Cessna 150 M aircraft attempted a take‐off at Moorabbin General Aviation Airport in Australia. Just after take‐off, the engine lost all power. The pilot managed a forced landing onto the grass at the end of the runway. On touch down, the engine resumed power. This event led to approximately 5000 piston engine aircraft being grounded and triggered an investigation from the refinery that manufactured the fuel in the plane. An independent investigation by the Australian Transport Safety Bureau determined that a series of cumulative changes in how the fuel was manufactured led to the carry over of a corrosion inhibitor, which contaminated the fuel. Cumulative changes are often hard to track, as their consequences may not be readily apparent. This paper will explore the cumulative changes that occurred and how the application of a new risk assessment technique, Delta HAZOP, might have assisted in uncovering the impacts of the cumulative changes. Delta HAZOP views a system more holistically and looks for the impacts of cumulative changes to uncover risks that may be missed via the guideword approach.

Women’s lifetime reproductive profiles and frailty among aging individuals in the USA and the Philippines

Frailty, particularly traits which are related to sex steroid hormone production, results from the age-associated decline in function considered to be part of the typical aging process. This process may vary with influences including environmental, biological, or lifestyle factors. An area of concern that has received relatively little attention is the impact of cumulative lifetime changes in sex steroid hormones related to the traits we see that typify the human aging process. Women’s lifetime reproductive profiles include menstrual/ovulatory cycles, gestation, and lactation, all of which respond to changes in sex steroid hormone levels. Here, we review data on reproductive profiles and risks of frailty among post-menopausal women. In the current study, our team collected reproductive histories of women to determine the estimated number of lifetime reproductive cycles (ELC). We interviewed 44 women in the USA and 67 women in the Philippines aged 65 years plus to obtain data on reproductive cycles, pregnancy, and breastfeeding. Participants completed several frailty tasks including grip strength, a sit-to-stand test, and gait speed. While ELC was not associated with frailty in the US population, higher ELC was associated with lower frailty among the Philippine population. The current study should be considered as an exploratory project investigating field-friendly methods to use when considering lifetime reproductive histories and the influence on the aging process.

Does artistic activity help kids avoid obesity? Emergent considerations in the ecology of childhood BMI

Although the positive relationship between arts engagement and mental health is well documented, arts participation may be an emergent factor in the ecology of childhood obesity. Prior research hypothesized several potential health benefits of arts participation including healthy diet and lifestyles, but the available evidence is mainly limited to cross-sectional covariate-adjustment models for the adult population. We employed a newly released panel of the Early Childhood Longitudinal Study kindergarten cohort (ECLS-K: 2011), which is a nationally representative sample of American children who entered kindergarten in 2010–2011 (n = 15,820). We applied both dynamic panel models with Maximum Likelihood estimation as well as difference-in-differences models to address unobserved heterogeneity. Our results showed that childhood arts activity is significantly associated with reduced weight status in elementary schooling. In particular, arts participation in elementary schooling reduced the risk of being overweight on a year-to-year basis; the effect size was between 12% and 23% of a SD of BMI for all children. Arts participation at kindergarten also had a significant relationship with cumulative changes in BMI over the course of elementary schooling, especially for female and White female children (about 22% and 32% of a SD of BMI). There are considerable arts participation gaps between families and regions, and these early artistic experiences appear to affect the risk of being overweight. This suggests the possibility of a larger social reproduction process via an ecological pathway that might be easily overlooked—the accumulation of arts experience and concurrent health inequalities in childhood.

LipidClock: A Lipid-Based Predictor of Biological Age.

Complexity is a fundamental feature of biological systems. Omics techniques like lipidomics can simultaneously quantify many thousands of molecules, thereby directly capturing the underlying biological complexity. However, this approach transfers the original biological complexity to the resulting datasets, posing challenges in data reduction and analysis. Aging is a prime example of a process that exhibits complex behaviour across multiple scales of biological organisation. The aging process is characterised by slow, cumulative and detrimental changes that are driven by intrinsic biological stochasticity and mediated through non-linear interactions and feedback within and between these levels of organization (ranging from metabolites, macromolecules, organelles and cells to tissue and organs). Only collectively and over long timeframes do these changes manifest as the exponential increases in morbidity and mortality that define biological aging, making aging a problem more difficult to study than the aetiologies of specific diseases. But aging’s time dependence can also be exploited to extract key insights into its underlying biology. Here we explore this idea by using data on changes in lipid composition across the lifespan of an organism to construct and test a LipidClock to predict biological age in the nematode Caenorhabdits elegans. The LipidClock consist of a feature transformation via Principal Component Analysis followed by Elastic Net regression and yields and Mean Absolute Error of 1.45 days for wild type animals and 4.13 days when applied to mutant strains with lifespans that are substantially different from that of wild type. Gompertz aging rates predicted by the LipidClock can be used to simulate survival curves that are in agreement with those from lifespan experiments.

The Off-Table Technique Increases Operating Room Efficiency in Direct Anterior Hip Replacement

BackgroundWhen performing a total hip arthroplasty via the direct anterior approach (DAA), many orthopedic surgeons utilize an orthopedic traction table. This technique requires an expensive table, time for positioning, staff to operate the table, and time-consuming transitions when preparing the femur. Some surgeons advocate for an “off-table” technique to avoid these difficulties. In this paper, we compare operating room efficiency between on-table and off-table techniques.Material and methodsWe retrospectively reviewed patients undergoing total hip arthroplasty by a single surgeon across the transition from on-table to off-table DAA technique. Three cohorts were defined; the last 40 on-table hips, the first 40 off-table hips, followed by the second 40 hips. Timestamps from the operative record were recorded to calculate setup, surgical, takedown, and total room time. Implant fixation, patient demographic data, comorbidities, and complications were recorded.ResultsFrom cohort 1 to 2, there was a 7-minute (14.44%, P = .0002) improvement in setup time but no change in total room time. From cohort 2 to 3, there was an additional 7-minute (15.47%, P < .0001) improvement in setup time, 32-minute (25.88%, P < .0001) improvement in surgical time, and 40-minute (21.96%, P < .0001) improvement in total room time yielding cumulative changes from cohort 1 to 3 of 15 minutes (27.68%, P < .0001), 28 minutes (23.11%, P < .0001), and 43 minutes (23.37%, P < .0001), respectively. There was no correlation between height, weight, or body mass index and time at any interval.ConclusionConversion to an off-table DAA technique offers an improvement in operating room efficiency. This is seen in setup, operative, and total room time. Implementation could allow for an additional case each day.

RNA bisulfite sequencing reveals NSUN2-mediated suppression of epithelial differentiation in pancreatic cancer.

Posttranscriptional modifications in RNA have been considered to contribute to disease pathogenesis and tumor progression. NOL1/NOP2/Sun domain family member 2 (NSUN2) is an RNA methyltransferase that promotes tumor progression in several cancers. Pancreatic cancer relapse inevitably occurs even in cases where primary tumors have been successfully treated. Associations of cancer progression due to reprogramming of the cancer methyl-metabolome and the cancer genome have been noted, but the effect of base modifications, namely 5-methylcytosine (m5C), in the transcriptome remains unclear. Aberrant regulation of 5-methylcytosine turnover in cancer may affect posttranscriptional modifications in coding and noncoding RNAs in disease pathogenesis. Mutations in NSUN2 have been reported as drivers of neurodevelopmental disorders in mice, and upregulated expression of NSUN2 in tumors of the breast, bladder, and pancreas has been reported. In this study, we conducted mRNA whole transcriptomic bisulfite sequencing to categorize NSUN2 target sites in the mRNA of human pancreatic cancer cells. We identified a total of 2829 frequent m5C sites in mRNA from pancreatic cancer cells. A total of 90.9% (2572/2829) of these m5C sites were mapped to annotated genes in autosomes and sex chromosomes X and Y. Immunohistochemistry staining confirmed that the NSUN2 expression was significantly upregulated in cancer lesions in the LSL-KrasG12D/+;Trp53fl/fl;Pdx1-Cre (KPC) spontaneous pancreatic cancer mouse model induced by Pdx1-driven Cre/lox system expressing mutant KrasG12D and p53 deletion. The in vitro phenotypic analysis of NSUN2 knockdown showed mild effects on pancreatic cancer cell 2D/3D growth, morphology and gemcitabine sensitivity in the early phase of tumorigenesis, but cumulative changes after multiple cell doubling passages over time were required for these mutations to accumulate. Syngeneic transplantation of NSUN2-knockdown KPC cells via subcutaneous injection showed decreased stromal fibrosis and restored differentiation of ductal epithelium in vivo. SIGNIFICANCE: Transcriptome-wide mRNA bisulfite sequencing identified candidate m5C sites of mRNAs in human pancreatic cancer cells. NSUN2-mediated m5C mRNA metabolism was observed in a mouse model of pancreatic cancer. NSUN2 regulates cancer progression and epithelial differentiation via mRNA methylation.

Indigenous mental health and climate change: A systematic literature review

Indigenous Peoples are among the most vulnerable to adverse mental health impacts resulting from climate change globally. In the context of a continually changing climate, an understanding of the diverse risks, impact, and responses of Indigenous communities to climate related mental health impacts is timely. The present study conducted a systematic literature review on the related effects, mechanisms of vulnerability, and adaptive responses and coping strategies to climate change related mental health impacts specific to global Indigenous Peoples. This review systematically selected articles from Scopus, MEDLINE, and Google Scholar, published since 2000. Twenty-three original studies were included for full review. The results confirmed direct impacts commonly caused by cumulative changes in climate increased non-clinical mental health impacts with the potential to develop to clinical mental illnesses with repeated, ongoing exposure. Also, indirect impacts further exacerbated various mechanisms of vulnerability amongst Indigenous communities, introducing unique intangible losses relating to place attachment, culture, food security and other socio-economic disadvantages. These results were dominated by specific regions, with few quantitative studies. This review emphasises the importance of engaging with Indigenous communities in responding to climate change, incorporating both qualitative and quantitative methods to capture indirect impacts to mental health, and understanding the priorities and existing adaption strategies that could integrate Indigenous cultures and knowledge.

Tree growth response to drought partially explains regional-scale growth and mortality patterns in Iberian forests.

Tree-ring data has been widely used to inform about tree growth responses to drought at the individual scale, but less is known about how tree growth sensitivity to drought scales up driving changes in forest dynamics. Here, we related tree-ring growth chronologies and stand-level forest changes in basal area from two independent data sets to test if tree-ring responses to drought match stand forest dynamics (stand basal area growth, ingrowth, and mortality). We assessed if tree growth and changes in forest basal area covary as a function of spatial scale and tree taxa (gymnosperm or angiosperm). To this end, we compared a tree-ring network with stand data from the Spanish National Forest Inventory. We focused on the cumulative impact of drought on tree growth and demography in the period 1981-2005. Drought years were identified by the Standardized Precipitation Evapotranspiration Index, and their impacts on tree growth by quantifying tree-ring width reductions. We hypothesized that forests with greater drought impacts on tree growth will also show reduced stand basal area growth and ingrowth and enhanced mortality. This is expected to occur in forests dominated by gymnosperms on drought-prone regions. Cumulative growth reductions during dry years were higher in forests dominated by gymnosperms and presented a greater magnitude and spatial autocorrelation than for angiosperms. Cumulative drought-induced tree growth reductions and changes in forest basal area were related, but initial stand density and basal area were the main factors driving changes in basal area. In drought-prone gymnosperm forests, we observed that sites with greater growth reductions had lower stand basal area growth and greater mortality. Consequently, stand basal area, forest growth, and ingrowth in regions with large drought impacts was significantly lower than in regions less impacted by drought. Tree growth sensitivity to drought can be used as a predictor of gymnosperm demographic rates in terms of stand basal area growth and ingrowth at regional scales, but further studies may try to disentangle how initial stand density modulates such relationships. Drought-induced growth reductions and their cumulative impacts have strong potential to be used as early-warning indicators of regional forest vulnerability.

The Impact of Rising Reservoir Water Level on the Gravity Field and Seismic Activity in the Reservoir Area: Evidence from the Impoundment of the Three Gorges Reservoir (China)

Using the test–retest data of the relative gravity field and earthquake monitoring catalog of the Three Gorges Reservoir (TGR) from October 2001 to October 2009, this paper systematically analyzes the changes in the gravity field in the head area of the reservoir and the temporal and spatial distribution characteristics of seismic activity during the impoundment process. It also employs the surrogate reshuffling tests to calculate the cross-correlation between the reservoir water level and the seismic activity sequence and discusses the influence of the rising reservoir water level on the gravity field and seismic activity in the reservoir region. Then, by constructing a three-dimensional finite-difference model based on the theory of fluid–solid coupling, the mechanism of reservoir-induced earthquakes is discussed from the aspects of direct reservoir water load and reservoir water infiltration. The results show that: (1) The rising reservoir water level has had a critical impact on the gravity field and seismic activity in the reservoir’s head area. The cumulative changes in the gravity field from October 2001 to November 2008 show that water impounding has led to a huge banded positive anomaly of gravity along the river near Xiangxi, which reached 450 × 10−8 ms−2. The seismicity activity dominated by micro-earthquakes after a 135 m water level rose rapidly, and the monthly average earthquake frequency increased from 2.00 before the impoundment to 92.60 after the 175 m stage. (2) From the beginning of the impoundment to the experimental impoundment stage of 175 m, the time series correlation test result between the monthly frequency of earthquakes and the water level of the reservoir also changed from uncorrelated before the water storage to correlated when the time lag was 0 months at a 95% confidence threshold. This indicates that the seismic activity obviously has a direct relationship with the load pressure produced by the rapid rise of the reservoir water level, which causes the instability of the mines, karst caves, shallow rock strata, and faults within 10 km along the river and near the reservoir bank, and consequently induces earthquakes. (3) As the TGR enters the 175 m high-level operation stage, the cross-correlation test confirmed that the seismic activity and the reservoir water level show negative correlation characteristics under the time lag of 4 to 5 months, indicating that the seismic activity has a lagging response to the reservoir water level change. The continued infiltration of the reservoir water, followed by the softening of the faults and other actions, triggered the Xiangxi M4.1 earthquake at the center of the four quadrants of gravity anomalies near Xiangxi on 22 November 2008. The Xiangxi segment of the reservoir and its periphery, a triangular geological region where the Xiannvshan faults, the Jiuwanxi fault, and the Yangtze River meet, might be at risk of having reservoir-induced tectonic earthquakes.