Dry-hot Conditions Research Articles

Time-varying moisture characteristics and C-S-H gel properties of concrete in dry and hot environments

The construction of deeply buried tunnels has intensified concerns regarding shrinkage cracking and the long-term performance deterioration of lining concrete in dry-hot environments. These issues are related to the dynamic interconversion of internal moisture states, the changing moisture behavior over time, and the evolution of calcium silicate hydrate (C-S-H) properties. However, the mechanisms underlying these phenomena are not fully understood. This study investigates the dynamics of moisture content across different states, the source and composition of evaporated water, as well as the mechanism of change in the microscopic properties of C-S-H in concrete subjected to dry-hot conditions (40℃ and 60℃) and standard curing environments through tests on water loss rates, chemically bound water, and low-field nuclear magnetic resonance. The findings reveal that at 40℃ and 60℃, hydration products were generated rapidly before mold removal, leading to significant increases in chemically bound water, interlayer water, and gel water, while capillary water was notably consumed. After mold removal, the rate of chemically bound water increase slowed, while interlayer water, gel water, and capillary water evaporated significantly, with gel water comprising 87.27 % and 83.51 % of the evaporated water at 40℃ and 60℃, respectively. From day 1 to day 28, interlayer water, gel water, and capillary water contents decreased significantly, with reductions of up to 85.98 % at 60℃. In dry-hot environments, moisture primarily exists as chemically bound water and gel water, contrasting with standard curing conditions where capillary water is also present. The study concludes that drying of C-S-H gels leads to both positive effects, such as interlayer space compression and increased indentation modulus, and negative effects, including increased microporosity and reduced matric densification, ultimately contributing to the deterioration of long-term mechanical properties.

Dynamic assessment of the impact of compound dry-hot conditions on global terrestrial water storage

Precipitation and temperature are critical factors influencing terrestrial water storage (TWS) can lead to unexpected TWS losses when compounded by dryness and high temperatures. Yet, a dynamic assessment of the individual and combined effects of these conditions on TWS is lacking. This study proposes a framework to assess TWS loss driven by compound dry-hot conditions (CDHC) and dynamically evaluates risk probabilities and thresholds for 2003–2012 and 2013–2022. Results showed that CDHC exert a greater impact on TWS than dry or hot conditions alone. The risk probabilities of global TWS loss are higher in the late period than in the early period, with risk probabilities for light and extreme levels increasing by approximately 9–11 % and 2–7 %, respectively. Although the resilience of water resource systems to CDHC has increased in some regions, it still shows a decreasing trend on a global scale. The decrease in the resilience to TWS in major hyperarid areas is primarily influenced by temperature, whereas that in arid areas is primarily affected by precipitation. These distinct patterns may be the primary factors contributing to the exacerbation of global TWS loss. This study provides a novel approach for the dynamic assessment of global TWS under CDHC. The research findings offer valuable insights for decision-makers developing adaptive strategies to mitigate future CDHC challenges.

Growth data of outlying plantations allows benchmarking the tolerance to climate extremes and drought stress in the European larch.

Plantations located outside the species distribution area represent natural experiments to assess tree tolerance to climate variability. Climate change amplifies warming-related drought stress but also leads to more climate extremes. We studied plantations of the European larch (Larix decidua), a conifer native to central and eastern Europe, in northern Spain. We used climate, drought and tree-ring data from four larch plantations including wet (Valgañón, site V; Santurde, site S), intermediate (Ribavellosa, site R) and dry (Santa Marina, site M) sites. We aimed to benchmark the larch tolerance to climate and drought stress by analysing the relationships between radial growth increment (hereafter growth), climate data (temperature, precipitation, radiation) and a drought index. Basal area increment (BAI) was the lowest in the driest site M (5.2 cm2 yr-1; period 1988-2022), followed by site R (7.5 cm2 yr-1), with the youngest and oldest and trees being planted in M (35 years) and R (150 years) sites. BAI peaked in the wettest sites (V; 10.4 cm2 yr-1; S, 10.8 cm2 yr-1). We detected a sharp BAI reduction (30% of the regional mean) in 2001 when springto-summer conditions were very dry. In the wettest V and S sites, larch growth positively responded to current March and June-July radiation, but negatively to March precipitation. In the R site, high April precipitation enhanced growth. In the driest M site, warm conditions in the late prior winter and current spring improved growth, but warm-sunny conditions in July and dry-sunny conditions in August reduced it. Larch growth positively responded to spring-summer wet conditions considering short (1-6 months) and long (9-24 months) time scales in dry (site M) and wet-intermediate (sites S and R) sites, respectively. Larch growth is vulnerable to drought stress in dry slow-growing plantations, but also to extreme spring wet-cloudy events followed by dry-hot conditions in wet fast-growing plantations.

Irrigation Cooling Effect on Local Temperatures in the North China Plain Based on an Improved Detection Method

Irrigation has excellent potential for altering surface characteristics and the local climate. Although studies using site observations or remote sensing data have demonstrated an irrigation cooling effect (ICE) on the air temperature (Tem) and land surface temperature (LST), it is difficult to eliminate other stress factors due to different backgrounds. We characterized the irrigation effect as the differences (Δ) of LST and DCT (DCT = LST − Tem) between irrigated and adjacent non-irrigated areas. An improved method was proposed to detect it over the North China Plain (NCP) based on satellite observations. We also investigated the effects of irrigation on Tem, precipitation, NDVI, and ET, and explored the relationships between them. The results show that irrigation induced a decrease in the daytime/nighttime LST and DCT (−0.13/−0.09 and −0.14/−0.07 °C yr−1), Tem (−0.023 °C in spring), and precipitation (−1.461 mm yr−1), and an increase in NDVI (0.03 in spring) and ET (0.289 mm yr−1) across the NCP. The effect on nighttime LST and NDVI increased by 0.04 °C 10 yr−1 and 0.003 10 yr−1, and that on ET weakened by 0.23 mm 10 yr−1 during 2000–2015. The ICE on the LST had evident spatiotemporal heterogeneity, which was greater in the daytime, in the spring, and in the northern area of the NCP (dry–hot conditions). The daytime ICE in the NCP and northern NCP was 0.37 and 0.50 °C during spring, respectively, with the strongest ICE of 0.60 °C in Henan; however, the ICE was less evident (<0.1 °C) in the southern NCP throughout the year. The ΔNDVI, ΔET, and ΔTem were the main factors driving ICE, explaining approximatively 22%, 45%, and 25% of the daytime ICE, respectively. For every unit of these measures that was increased, the daytime ICE increased by about 7.3, 4.6, and 1.5 °C, respectively. This study highlights the broad irrigation effect on LST, ET, NDVI, and the climate, and provides important information for predicting climate change in the future. The improved method is more suitable for regions with uneven terrain and a varying climate.

Droughts across China: Drought factors, prediction and impacts

Drought is a complicated and costly natural hazard and identification of critical drought factors is critical for modeling and forecasting of droughts and hence development of drought mitigation measures (the Standardized Precipitation-Evapotranspiration Index) in both space and time. Here we quantified relationships between drought and 23 drought factors using remote sensing data during the period of 2002–2016. Based on the Gradient Boosting Algorithm (GBM), we found that precipitation and soil moisture had relatively large contributions to droughts. During the growing season, the relative importance of Normalized Difference Water Index (NDWI-7) for SPEI3, SPEI6, SPEI9, and SPEI12 reached as high as 50%. However, during the non-growing season, the Snow Cover Fraction (SCF) had larger fractional relative importance for short-term droughts in the Inner Mongolia and the Loess Plateau which can reach as high as 10%. We also compared Extremely Randomized Trees (ERT), H2O-based Deep Learning (Model developed by H2O.deep learning in R H2O.DL), and Extreme Learning Machine (ELM) for drought prediction at various time scales, and found that the ERT model had the highest prediction performance with R2 > 0.72. Based on the Meta-Gaussian model, we quantified the probability of maize yield reduction in the North China Plain under different compound dry-hot conditions. Due to extreme drought and hot conditions, Shandong Province in North China had the highest probability of >80% of the maize yield reduction; due to the extreme hot conditions, Jiangsu Province in East China had the largest probability of >86% of the maize yield reduction.

Probabilistic assessments of the impacts of compound dry and hot events on global vegetation during growing seasons

The response of vegetation to climate extremes, including droughts and hot extremes, has been evaluated extensively in recent decades. However, quantitative assessments of individual and combined impacts of dry and hot conditions on vegetation are rather limited. In this study, we developed a multivariate approach for analyzing vegetation responses to dry, hot, and compound dry-hot conditions from a probabilistic perspective using precipitation, temperature, and the Normalized Difference Vegetation Index (NDVI) for the period from 1982 to 2015. The Standardized Precipitation Index (SPI) and Standardized Temperature Index (STI) were used to define individual and compound dry and hot conditions. Based on the diagnosis of the correlation between SPI/STI and NDVI during growing seasons, we investigated the conditional probability of vegetation decline under different climate conditions. The results showed that vegetation was affected by compound dry and hot conditions (defined as SPI ⩽ −1.3 and STI > 1.3) in arid and semi-arid regions. In these regions, the conditional probabilities of vegetation decline under compound dry and hot conditions increased by 7% and 28% compared with those under individual dry and hot conditions, respectively. The impact of compound dry and hot events on vegetation for different biomes was also assessed. Temperate grassland was found to be particularly vulnerable to compound dry and hot conditions. This study highlights the necessity of considering compound dry and hot extremes when assessing vegetation responses to climate extremes under global warming.

Changes in climate-crop yield relationships affect risks of crop yield reduction

The relationship between climate variables (e.g., precipitation and temperature) and crop yield has been used to assess the impacts of climate extremes (e.g., droughts, heatwaves) on crop yield, which is commonly assumed to be time-invariant. However, climate-yield relationships may change over time due to the influence of global warming and human interventions. In particular, the concurrent changes in the precipitation-yield relationship and the temperature-yield relationship could pose challenges to the development of adaptation measures for agriculture planning and management. The objective of this study is to propose a statistical approach to estimate the risk of crop yield reduction under the dry condition, hot condition, and compound dry-hot condition due to concurrent changes in climate-yield relationships. Results show that the relationship between climate and maize yield in the top ten maize-producing countries has changed from 1961-1988 to 1989-2016. The risk of crop yield reduction generally increases with enhanced dependence between dry conditions and crop yield (or hot conditions and crop yield). Based on the multivariate distribution, results show that the risk of maize yield reduction increases for the majority of these countries under compound dry-hot conditions due to concurrent changes in climate-yield relationships. Results of this study are expected to provide useful insights for assessing agriculture vulnerability under global warming.

СЭНДВИЧ ТИПИДАГИ ЗАМОНАВИЙ ЙИҒМА ТАШҚИ ДЕВОРЛАРНИНГ ИСТИҚБОЛЛИ КОНСТРУКТИВ ЕЧИМЛАРИ

As a result of theoretical and experimental experiments conducted in this study, the specifics of the temperature field in the heat-insulated parts of the outer wall of a hidden metal frame of a residential building built of cement sandwich panels in dry hot conditions of Uzbekistan were identified.

Properties of nanomodified concrete in dry hot external conditions

Based on the analysis of literary sources, the article determines the possibility of producing fine-grained concrete for monolithic concreting with water modified with structured colloidal surfactants. Peculiarities of monolithic concreting in dry hot conditions are given and the issues of preparation technology of fine-grained concrete based on cement systems with nanomodified structured colloidal surfactants water are considered. It combines knowledge of the laws of structure formation and modification of the systems “Portland cement - micro-fillers - superplasticizer - colloidal surfactants” to ensure the technological and operational properties of concrete in the face of changing factors of its technology and operation. An increase in the rate of heating of concrete leads to a decrease in the strength of concrete. However, the decrease in strength of concrete structured by colloidal surfactants is much less than in concrete that does not contain these substances. The results of studies have established that the use of superplasticized systems based on cement and structured water allows directionally controlling technological properties and creating a solid concrete structure with improved construction and technical properties during hardening in dry, hot temperature conditions. The results of the studies allow us to draw the following conclusions: the introduction of colloidal hydrophobic surfactants into the composition of concrete in ultra-low concentrations leads to a decrease in the stratification of cellular concrete along the height of the product; the introduction of concrete to colloidal hydrophobic surfactants in ultra-low concentrations leads to a decrease in its thermal conductivity; the introduction of colloidal hydrophobic surfactants into the composition of concrete in ultra-low concentrations leads to an increase in its stability, both to the action of elevated temperatures and low (frost). This creates the possibility of early loading of structures, shortening the production cycle, increasing the turnover of formwork and accelerating the construction of monolithic buildings and structures in dry, hot temperature conditions.

First evidence for the presence of Andisols in the dry-hot environment of the Arabian Shield

Saudi Arabia has many volcanoes and extensive basaltic lava fields known as harrats located along the western part of the Arabian Shield sub-parallel to the Red Sea. The soils developed on these volcanic materials have not yet been investigated. Forty representative soil profiles were selected from six harrats and their morphological and physicochemical properties as well as their mineralogical compositions were characterized using standard chemical, XRD, SEM, and TEM techniques. The main objective of this study was to determine if the soils developed from basaltic rocks in the harrats of the Arabian Shield are Andisols. The results revealed that all representative profiles had volcanic glass content that ranged from 15 to 40%, P-retention capacity >35%, and acid oxalate extractable A1o + 1/2 Feo that ranged from 0.44 to 2.20%. The crystalline clay minerals were dominated by smectite, kaolin (kaolinite/halloysite), and mica (illite), whereas, chlorite-hydroxy-interlayered vermiculite (Ch-HIV), palygorskite, Ca-zeolites, and pseudo-chlorite were present as minor components. Small amounts of allophane, imogolite, and ferrihydrite made up the poorly-crystalline clay minerals. All representative profiles satisfied the criteria for andic soil properties, and were classified as Torrands due to the presence of an aridic soil moisture regime in the area. Paleoclimatic conditions that existed in the Arabian Peninsula over the last few thousand years are consistent with the formation of andic and/or vitric soil properties. Because of this, Andisols developed from pyroclastic parent materials and are now present in dry-hot conditions. The presence of Andisols in the study area was demonstrated, and was mainly attributed to the influence of Pleistocene paleoclimatic conditions.

Quantifying likelihoods of extreme occurrences causing maize yield reduction at the global scale

A variety of weather and climate extremes (e.g., droughts, heatwaves) can lead to negative impacts on crop yields and food security. It is thus important to understand likelihoods of extreme occurrences causing crop yield reduction for enhanced resilience of the food system. Here, we investigate the likelihood of occurrences of dry, hot, and compound dry-hot conditions causing crop yield reduction for ten maize-producing countries based on climate observations and country-level maize yields for the period 1961–2016. The likelihood of occurrences of different extremes causing maize yield reduction is quantified using a multivariate statistical model. Results show that the multivariate model performs well in quantifying the likelihood of extreme occurrences (i.e., dry, hot and compound dry-hot conditions) causing maize yield reduction. Overall, the likelihood of occurrences of the above three conditions leading to yield reduction varies among ten maize-producing countries and that of compound dry-hot condition is the highest for most countries, which is shown to be closely related to the precipitation-temperature dependence of each country. Moreover, the likelihood of compound dry-hot occurrences becomes higher as the severity of crop yield reduction increases. These findings highlight significant impacts of compound dry-hot conditions on maize yield reduction and provide valuable information for formulating effective agricultural measures under global warming.

Probabilistic evaluation of the impact of compound dry-hot events on global maize yields

Weather and climate extremes, such as droughts and hot extremes, may result in marked damages to crop yields and threaten regional and global food security. Understanding the relationship between climate extremes and crop yields is of critical importance for food security under a changing climate. The objective of this study is to investigate the probabilistic variability of maize yields with respect to compound dry-hot events, which has been shown to be more stressful to crops compared with individual dry or hot events. A multivariate model is first constructed to model the joint behavior of the dry condition, hot condition, and crop yields. The response of crop yields under different dry, hot, and compound dry-hot conditions at national and global scales is then investigated based on the conditional distribution. For the major maize producing countries (top 5), the probability of maize yield reduction could increase by from 0.07 to 0.31 (from 0.04 to 0.31) when the individual extreme drought (extreme hot) conditions changed to compound dry-hot conditions. The probabilistic evaluation of compound dry-hot events' impacts on maize yields is expected to provide useful insights for the mitigation of compound events and their impacts under a changing climate.

Effects of olive oil mill wastewater on chemical, microbiological, and physical properties of soil incubated under four different climatic conditions

The objective of this study was to understand the degradation of the organic matter of olive mill wastewater (OMW) and its phytotoxic and water repellent effects in dependence on four different climatic conditions. We hypothesized that warm conditions with sufficient soil moisture ensure optimal biological activity and thus minimize negative effects of the OMW treatment. Therefore, OMW-treated soil was incubated for 60 days under four climatic conditions. During incubation, we monitored pH, contents of nitrate, manganese and phenolic compounds, soil respiration, soil water repellency, and δ13C. Additionally, calorific value and thermal stability of the soil organic matter at the beginning and end of incubation were determined. Soil samples of the wet-cold and moist-warm incubation were tested for phytotoxicity using a seed germination bioassay with Lepidium sativum. As a function of climatic conditions, positive and negative effects, e.g., addition of nutrients, phytotoxicity, and soil water repellency, were observed. Under dry-hot conditions, the soil was still water repellent after 60 days of incubation whereas the wet-hot, moist-warm, and wet-cold incubation show that soil would stay wettable if soil moisture before OMW treatment would be sufficient. Thus, the impact of OMW treatment on soil quality strongly depends on the environmental conditions which should favor an enhancement of microbial activity to minimize negative effects.

Adaptive, water-conserving strategies in Hedysarum mongolicum endemic to a desert shrubland ecosystem

Adaptive mechanisms in Hedysarum mongolicum to dry and hot conditions in desert areas remain unclear. In this work, the diurnal and seasonal dynamics of sap flow in H. mongolicum, endemic to a semi-arid desert shrubland ecosystem, were studied. Stem sap flow was continuously monitored with heat balance sensors from June to October, 2012. Diurnal pattern in sap flow per stem area (J s) revealed a clear seasonal trend, with J s peaking earlier in summer (~10:00 h, 3 h before solar noon, R s), than in autumn (at roughly the same time as R s). Seasonally, J s was positively correlated to leaf area index. Excluding effects of phenology, volumetric soil water content (VWC) affected J s the greatest. In general, VWC was revealed to regulate the degree of response of J s to meteorological factors [R s, temperature T, and water vapor pressure deficit (VPD)], with sap flow being more responsive to these factors when VWC was high (>0.09 m3 m−3). Under low VWC (<0.09 m3 m−3), positive response of J s to the meteorological factors became saturated (leveled off) or declined when dry-hot conditions exceeded an hourly mean T, R s, and VPD of 24 °C, 700 W m−2, and 2.1 kPa, respectively. The results showed that H. mongolicum shrubs adapt to hot-dry or water-limited conditions in summer by closing their stomata in mid-morning and reducing the sensitivity in J s to T, R s, and VPD. The understanding of adaptive mechanisms in desert shrub species could potentially provide important baseline information towards the ecological restoration and sustainable development of arid- and semi-arid ecosystems.

Конструктивные решения наружной стены при уширении корпусов жилых домов вторичной застройки в условиях сейсмической опасности и сухого жаркого климата Центральной Азии

Конструктивные решения наружной стены при уширении корпусов жилых домов вторичной застройки в условиях сейсмической опасности и сухого жаркого климата Центральной Азии

FUSARIUM SPP. ASSOCIATED TO CITRUS DRY ROOT ROT: AN EMERGING ISSUE FOR MEDITERRANEAN CITRICULTURE

FUSARIUM SPP. ASSOCIATED TO CITRUS DRY ROOT ROT: AN EMERGING ISSUE FOR MEDITERRANEAN CITRICULTURE

Decreased CO2 availability and inactivation of Rubisco limit photosynthesis in cotton plants under heat and drought stress in the field

Heat and drought stresses are often coincident and constitute major factors limiting global crop yields. A better understanding of plant responses to the combination of these stresses under production environments will facilitate efforts to improve yield and water use efficiencies in a climatically changing world. To evaluate photosynthetic performance under dry-hot conditions, four cotton (Gossypium barbadense L.) cultivars, Monseratt Sea Island (MS), Pima 32 (P32), Pima S-6 (S6) and Pima S-7 (S7), were studied under well-watered (WW) and water-limited (WL) conditions at a field site in central Arizona. Differences in canopy temperature and leaf relative water content under WL conditions indicated that, of the four cultivars, MS was the most drought-sensitive and S6 the most drought-tolerant. Net CO2 assimilation rates (A) and stomatal conductances (gs) decreased and leaf temperatures increased in WL compared to WW plants of all cultivars, but MS exhibited the greatest changes. The response of A to the intercellular CO2 concentration (A–Ci) showed that, along with stomatal closure, non-stomatal factors associated with heat stress also limited A under WL conditions, especially in MS. The activation state of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) decreased in WL compared to WW plants, consistent with thermal inhibition of Rubisco activase activity. The extent of Rubisco deactivation could account for the metabolic limitation to photosynthesis in MS. Taken together, these data reveal the complex relationship between water availability and heat stress for field-grown cotton plants in a semi-arid environment. Both diffusive (drought-stress-induced) and biochemical (heat-stress-induced) limitations contributed to decreased photosynthetic performance under dry-hot conditions.

Post-impact deposits in Tvären, a marine Middle Ordovician crater south of Stockholm, Sweden

AbstractThe well-preserved Tvären crater is noteworthy for being one of a small number of Early and Middle Ordovician impact structures formed in a marine environment. It is demonstrated to be an impact structure by the presence of a breccia lens, consisting of crystalline basement rocks, and shocked quartz. The breccia lens formed under dry-hot conditions after expulsion of sea-water by the impact. Resurging sea-water thereupon deposited a positively graded, 60 m thick turbidite-like unit. This graded resurge deposit is a previously unknown feature, to be expected in open-sea impacts. Breccia in the lower part of this graded deposit contains fragments of a remarkably complete orthoceratite limestone succession that existed at the site of impact, resting on non-lithified sand of probably Early to earliest Middle Cambrian age. A sedimentary succession was deposited inside the crater at depths decreasing from more than 200 m in the initial stages to some 100 m at the time of deposition of the youngest preserved beds. The environment within the crater thus favoured deposition of an essentially complete stratigraphic succession with depth-controlled palaeoecology for a significant time interval after the impact. Whereas planktonic members, like graptolites and chitinozoa, are present throughout the post-impact succession, and asaphids, almost as persistent, became established at an early date, burrowers were somewhat reluctant to enter and remopleuridids and small strophomenids came in at a late stage. We suggest as a result of this study that structures formed by impact may offer unique information about the palaeogeology and palaeoenvironment of the region hit by the impact.

Stomatal Response of some Cultivated and Wild Tuber-bearing Potatoes in Warm Tropics as Influenced by Water Deficits

Leaf resistances of 14 cultivated potato genotypes (Solanum spp.) and three tuber-bearing wild Solanum species were compared when plants were grown under water stress at two tropical sites. Factors investigated were diurnal changes in leaf resistance, the effect of plant age, transient drought versus well-watered conditions of potted and field-grown plants. These measurements were carried out in order to determine the stomatal behaviour of tuber-bearing genotypes and species. Significant genotypic differences in leaf resistances were noted within the cultivated genotypes. All genotypes had higher resistances when water-stressed, but LT-7 appeared to have the lowest leaf resistances. Genetic differences in stomatal behaviour of tuber-bearing Solanum species were confirmed. Abaxial stomatal resistances of water-stressed plants of the species ranged between 1.74 and 13.8 s cm-1. Stomata of S. chacoense were less affected by drought (three-fold) than S. tuberosum (four-fold). The greatest effect was on S. jungasense (five-fold) and on S. raphanifolium. These data show that stomata behaviour among tuber-bearing Solanum species is sufficiently different to warrant investigations of drought-resistance in potato species under dry hot conditions.

Water-use Efficiency of Trifolium alexandrinum Exposed to Salt Stress under Different Environmental Conditions

Summary Trifolium alexandrinum L. was cultivated under salt stress and under 3 sets of environmental conditions. In a field study in the northern Negev Desert (Israel) a sand-pot cultivation was used to study salt response and water-use efficiency (WUE) under a dry, hot climate. At moderate salinity (50mM NaCl) growth of plants was only reduced by 22 % and WUE increased significantly with respect to control plants. Leaf to stem ratios significantly decreased with the salt treatment. In an open-air experiment in Australia under dry hot conditions but in solution culture, dry matter production of plants from a 50 mM NaCl treatment was reduced by 70 %, leaf to stem ratio increased, and WUE decreased significantly. In a solution-culture experiment in a glasshouse, a 50 mM NaCl treatment reduced growth of plants by 62 %, and leaf to stem ratio increased. Salinity had no effect on WUE. Possible underlying mechanisms of these phenomena are being discussed.