Levels Of Environmental Stress Research Articles

A burrowing ecosystem engineer positively affects its microbial prey under stressful conditions.

Species that facilitate others under stressful conditions are often ecosystem engineers: organisms that modify or create physical habitat.However, the net effect of an engineering species on another depends on both the magnitude of the direct interactions (e.g., competition or predation) and the specific environmental context.We used a laboratory system to isolate the trophic and engineering impacts of a predator, the nematode Caenorhabditis remanei, on its prey, Escherichia coli under different levels of environmental stress. We predicted that under stressful surface conditions the nematodes would positively impact their prey by creating burrows which protected the bacteria.Colony plate counts of E. coli indicated that there was a stress‐induced change in the net impact of nematodes on bacteria from neutral to positive. Predator engineering in the form of burrowing allowed larger bacteria populations to survive.We conclude that even in a simple two‐species system a predator can positively impact prey via ecosystem engineering.

The Effects of Music Intervention on Environmental Stress and Sleep Quality in Patients with Liver Transplantation

Purpose The purpose of this study was to examine effects of music intervention on environmental stress and sleep quality in liver transplant patients who are receiving care in one-person isolation rooms of an ICU. Methods The study was a quasi-experimental design pre-and-post nonequivalent control group. Participants were 37 patients (18 in the experimental group and 19 in the control group) who, after receiving liver transplant, were hospitalized in one-person isolation rooms of the ICU. The study covered patients admitted between August 2016 and December 2017. Earplugs and sleep shades were provided as ordinary care to both experimental and control groups, and music intervention was provided to the experimental group three times a day for 30 minutes each from the first day of hospitalization. Results The first hypothesis, “The experimental group who received music intervention will experience a lower environmental stress level than the control group” was supported (Z=-3.212, p<.001). The second hypothesis, “The experimental group who received music intervention will experience a higher sleep quality than the control group” was also supported (t=3.715, p=.001). Conclusion Findings show that music intervention is an effective nursing intervention to reduce environmental stress and improve sleep quality in liver transplant patients in the ICU. 주요어: 간이식, ìŒì• ì¤‘ìž¬, 중환자실, 환경 ìŠ¤íŠ¸ë ˆìŠ¤, 수면의 질 Key words: Liver transplantation, Music therapy, Intensive care units

Recent advances in the characterization of plant transcriptomes in response to drought, salinity, heat, and cold stress.

Despite recent advancements in plant molecular biology and biotechnology, providing food security for an increasing world population remains a challenge. Drought (water scarcity), salinity, heat, and cold stress are considered major limiting factors that affect crop production both qualitatively and quantitatively. Therefore, the development of cost-effective and environmentally friendly strategies will be needed to resolve these agricultural problems. This will require a comprehensive understanding of transcriptomic alterations that occur in plants in response to varying levels of environmental stresses, singly and in combination. Here, we briefly discuss the current status and future challenges in plant research related to understanding transcriptional changes that occur in response to drought, salinity, heat, and cold stress.

Effects of heart rate variability biofeedback training on psychological state and cardiac autonomic regulation in stressed people

IntroductionPsychological stress is common in our fast‐paced society and strongly influences mental and physical well‐being. Specific training methods have been recently proposed to deal with the negative effects of stress. heart rate variability biofeedback training, a method whereby the subject controls an unusually breathing rate to reach cardiac coherence, has been shown to reduce anxiety and improve cardiac autonomic dynamics in diseased people as well as in young competitors. The present study was designed to examine the effects of short sessions of biofeedback (BFB) training in subjects classified as being severely stressed.MethodsTwenty‐four participants characterized by a high level of state anxiety, were randomly assigned into a BFB group (n=12) or a control Group (n=12). In the BFB group, cardiac coherence training using a biofeedback device (URGOfeel®, URGOTECH) was conducted during 5 weeks, 5‐min twice a day.Subjects completed two sessions of tests (before and after 5‐weeks BFB training). Each session consisted in 4 conditions, a baseline “quiet” condition, a condition of cognitive tasks (to assess different domains of executive functioning), and two conditions of cognitive tasks associated to two levels of environmental‐induced stress. To create gradual level of environmental stress, the experimental context was modified by generating visual and sound interferences with negative feedback and time pressure. Heartbeat intervals were recorded (Polar Belt) for 10‐min both at baseline and after 5‐weeks BFB training and was assessed in temporal domain (RMSSD) and from non‐linear analyses (entropy index calculated from MultiScale Entropy, MSE). Participants filled out a series of questionnaires on‐line, notably the Spielberger state anxiety questionnaire (STAI) and the NASA‐TLX to measure the impact of stress on anxiety and workload, before and after each session and conditions.ResultsBefore BFB training the induced stress, was associated with a high level of anxiety and a low entropy when compared to baseline and cognitive tasks conditions. After BFB training, both psychological state and entropy in cardiac dynamics were improved in every condition.Conclusionthe present study confirms the blunting of physiological complexity in heart rate dynamics in stressed subjects especially under acute stress. The phenomenon is generally associated with an altered heart‐brain interconnectivity and a lesser adaptive capacity to everchanging environments. The main outcome here was the efficiency of (very) short BFB training sessions to restore an improved autonomic control in stressed subjects whatever their environment.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Health risk assessment for highway toll station workers exposed to PM2.5-bound heavy metals

Highway toll station workers exposed to vehicle emissions during their working time, could induce excessive reactive oxygen species (ROS) generation and lead to significant health effects. This study conducted a comprehensive exposure investigation of environmental pollutants and oxidative stress levels for highway toll station workers during March–May 2014 in Tianjin, China. PM2.5 exposure samples were collected by personal monitors during worker’ day-shift working time (9:00 a.m. - 5:00 p.m.), and particulate heavy metals were analyzed by ICP-MS. Urinary 8-OHdG concentrations were analyzed in pre- and post-work urine samples from selected subjects to reflect their oxidative stress (OS) level variation. Results showed that PM2.5 average exposure concentration was 230.73 ± 142.99 μg m−3. Pb, Zn and Cr were the most abundant elements of metals, accounting for over 70% of total particulate heavy metals. Values based on geoaccumulation index (Igeo) and enrichment factor (EF) analysis indicated that heavy metals including Pb, As, Cd, Cr, Ni, Cu, Zn were mainly derived from anthropogenic sources, presenting heavily pollution levels. Health assessment was conducted using integrated toxicity values and Monte Carlo simulation, and results indicated that exposure to PM2.5-bound heavy metals can trigger significant adverse non-carcinogenic and carcinogenic risk. Urinary 8-OHdG concentrations of participants elevated over 2 times after their day-shift working exposure, indicating that pollutants from vehicle emission could cause DNA damage for highway toll station workers. However, we did not find significant association between fine particle-bound heavy metals and urinary 8-OHdG levels. Much work should be conducted in the future study focusing on confounding factors.

Biogeomorphic feedbacks and the ecosystem engineering of recently deglaciated terrain

Matthews’ 1992 geoecological model of vegetation succession within glacial forefields describes how following deglaciation the landscape evolves over time as the result of both biotic and abiotic factors, with the importance of each depending on the level of environmental stress within the system. We focus in this paper on how new understandings of abiotic factors and the potential for biogeomorphic feedbacks between abiotic and biotic factors makes further development of this model important. Disturbance and water dynamics are two abiotic factors that have been shown to create stress gradients that can drive early ecosystem succession. The subsequent establishment of microbial communities and vegetation can then result in biogeomorphic feedbacks via ecosystem engineering that influence the role of disturbance and water dynamics within the system. Microbes can act as ecosystem engineers by supplying nutrients (via remineralization of organic matter and nitrogen fixation), enhancing soil development, either decreasing (encouraging weathering) or increasing (binding sediment grains) geomorphic stability, and helping retain soil moisture. Vegetation can act as an ecosystem engineer by fixing nitrogen, enhancing soil development, modifying microbial community structure, creating seed banks, and increasing geomorphic stability. The feedbacks between vegetation and water dynamics in glacial forefields are still poorly studied. We propose a synthesized model of ecosystem succession within glacial forefields that combines Matthews’ initial geoecological model and Corenblit's model to illustrate how gradients in environmental stress combined with successional time drive the balance between abiotic and biotic factors and ultimately determine the successional stage and potential for biogeomorphic feedbacks.

Dysregulation of autophagy and stress granule-related proteins in stress-driven Tau pathology.

Imbalance of neuronal proteostasis associated with misfolding and aggregation of Tau protein is a common neurodegenerative feature in Alzheimer's disease (AD) and other Tauopathies. Consistent with suggestions that lifetime stress may be an important AD precipitating factor, we previously reported that environmental stress and high glucocorticoid (GC) levels induce accumulation of aggregated Tau; however, the molecular mechanisms for such process remain unclear. Herein, we monitor a novel interplay between RNA-binding proteins (RBPs) and autophagic machinery in the underlying mechanisms through which chronic stress and high GC levels impact on Tau proteostasis precipitating Tau aggregation. Using molecular, pharmacological and behavioral analysis, we demonstrate that chronic stress and high GC trigger mTOR-dependent inhibition of autophagy, leading to accumulation of Tau aggregates and cell death in P301L-Tau expressing mice and cells. In parallel, we found that environmental stress and GC disturb cellular homeostasis and trigger the insoluble accumulation of different RBPs, such as PABP, G3BP1, TIA-1, and FUS, shown to form stress granules (SGs) and Tau aggregation. Interestingly, an mTOR-driven pharmacological stimulation of autophagy attenuates the GC-driven accumulation of Tau and SG-related proteins as well as the related cell death, suggesting a critical interface between autophagy and the response of the SG-related protein in the neurodegenerative potential of chronic stress and GC. These studies provide novel insights into the RNA-protein intracellular signaling regulating the precipitating role of environmental stress and GC on Tau-driven brain pathology.

Abstract P201: Exposure to Stress and Low Salt Diet Increases Blood Pressure in Mice Lacking the Brain-Specific Renin Isoform Renin-b

Previous experience to various hypertensive conditions including psychosocial stress and high or low salt diet enhances the response to subsequent hypertensive challenges. Importantly, the activation of the brain renin angiotensin system (RAS) is required for the sensitization to these hypertensive challenges. We previously reported that the brain-specific renin isoform (Ren-b) tonically inhibits the activation of the brain RAS and the ablation of Ren-b results in brain RAS disinhibition leading to hypertension. Interestingly, we observed a high degree of variability in the blood pressure (BP) between Ren-b KO cohorts that can be attributed to different levels of environmental stress. Thus, BP and heart rate (HR) from five separate experimental cohorts which were subjected to different levels of stress were re-analyzed and compared. In cohorts that were not subjected to any surgical procedures, Ren-b KO mice housed in a stressful environment exhibited higher systolic BP (cohort 1, KO: 130 ± 1 vs WT: 122 ± 1 mmHg, p&lt;0.05) in comparison with animals housed in a quiet and more regulated environment (cohort 2; KO: 116 ± 1 mmHg vs WT: 116 ± 1). BP was selectively higher in Ren-b KO mice subjected to a surgical procedure required to study a BP mechanism (Cohort 3, KO: 137 ± 2 vs WT: 117 ± 3, p&lt;0.05; Cohort 4, KO: 139 ± 2 vs WT: 112 ± 6, p&lt;0.05; Cohort 5, KO: 137 ± 3 vs WT: 113 ± 3 mmHg, p&lt;0.05). Similarly, elevation of BP was associated with increased HR. Altogether this reanalysis of pre-existing data suggests that Ren-b KO mice might be sensitive to environmental or surgical stressors. Next, we hypothesized that Ren-b KO mice are sensitized to high salt diet, thus BP was acquired in WT or Ren-b KO fed low or high salt diet (0.3% and 4.0% NaCl, respectively) for a week in a quiet environment. On high salt diet, Ren-b KO did not manifest an increase in mean BP (WT: 113±2 vs KO: 109±2 mmHg, p=0.18), indicating that Ren-b KO are not salt-sensitive. In contrast, on low salt diet Ren-b KO exhibited modest increase in mean BP compared to WT (WT: 108±2 vs KO: 113±1 mmHg, p&lt;0.05) indicating that Ren-b KO might be sensitive to conditions that exacerbate activation of peripheral RAS. We conclude that disinhibition of brain RAS by the ablation of Ren-b leads to exaggerated response to hypertensive challenges.

Developmental stability and environmental stress: A geometric morphometrics analysis of asymmetry in the human femur.

The evaluation of developmental stability (DS) by measuring fluctuating asymmetry (FA), a bioindicator of general cumulative stress, is an approach that has often been used to characterize health status in past populations. New techniques of geometric morphometrics now enable a better appreciation of FA than before, with a more refined quantification of variation. The aim of our study is to determine the effectiveness of geometric morphometrics analyses of asymmetry in the human femur for the study of individual DS and inferring health status of human populations. We conducted a comparative analysis between two diachronic populations of distinct and known health status. Two samples of 70 pairs of adult femurs from individuals of comparable age range and sex were selected and CT-scanned. For each 3D reconstruction, two sets of 27 landmarks were digitized to quantify and minimize the effect of measurement error on the evaluation of FA. While the measurement of FA in femoral centroid size seemed comparable between the samples, the amount of FA in femoral shape differed. Individuals who experienced high levels of environmental stress presented higher intra-individual variation. In parallel, results did not reveal any significant differences in DS between sexes or age groups. The geometric morphometrics analysis of femoral asymmetry was effective for distinguishing two populations. After considering various factors of influence, genetics and biomechanics seem to have a limited impact on the results. Expressing FA appears to be normal but dependent on the disturbances of DS produced by environmental stress.

Abundance-Biomass Comparison approach to assess the environmental stressors in Diyawannawa wetland in monsoonal and non-monsoonal seasons

Abundance-Biomass Comparison (ABC) approach is a graphical approach that compares the abundance and biomass of organisms in order to predict the environmental stress level of an ecosystem. The present study was conducted in selected sites located at non-rehabilitated and rehabilitated areas of the Diyawannawa wetland in Sri Lanka in the monsoonal and non-monsoonal seasons. The ABC was performed on the macrobenthic mollusk species collected from the study sites. Eight species of macrobenthic mollusks, namely, Bithynia tentaculata, Melanoides turbeculata, Melanoides turriculus, Thiara scabra, Lamellidens marginalis, Pila globosa, Gyraulus saigonensis and Lymnaea stagnalis were recorded during the study period. Based on Principal Component Analysis, B. tentaculata, and, P. globosa were identified as characteristic gastropod species that could be used to classify study sites in the rehabilitated and non-rehabilitated areas of this tropical wetland system. In the monsoonal season, overlapping cumulative percentage dominance of abundance and cumulative percentage dominance of biomass curves in sites A, B, and F indicated partially disturbed environmental conditions. The site C of the non-rehabilitated area, showed a typical undisturbed condition and the sites D and E of the rehabilitated area the cumulative percentage dominance of biomass curve was located above the abundance curve, indicating disturbed environmental conditions in these sites during monsoonal season. During the non-monsoonal season in all the sites except site F of the rehabilitated area, the cumulative percentage dominance of abundance curve was located above the biomass curve, indicating undisturbed environmental conditions in these sites. In the site F, the cumulative percentage dominance of abundance and the cumulative percentage dominance of biomass curves were crossing each other, indicating partially disturbed environmental conditions at this site. The values of the W statistic, which ranged from 0.004 to 0.374 in the non-monsoonal season and ranged from 0.1 to 0.2 in the monsoonal season, and pollution and water quality categorization by modified biotic index (MBI) were in agreement with the results of the ABC approach.

Fluctuating Dental Arch Asymmetry in Different Malocclusion Groups.

ObjectiveTo compare the degree of dental arch fluctuating asymmetry (FA) among patients with Class I, II, and III malocclusions.Subjects and methodsThe sample comprised randomly selected plaster casts of 131 patients: 39 Class I (19 males and 20 females), 57 Class II (23 males and 34 females), and 35 Class III (20 males and 15 females). Dental models were scanned and digitized using ATOS II SO. The measurements of the teeth and dental arches were taken using the ATOS viewer version 6.A.2 software. Six arch widths and five arch depths were measured. The FA was assessed as a composite index of total weighted asymmetry (TWA). The analysis of variance was used to determine whether there were any statistically significant differences between the groups.ResultsComposite TWA measures of fluctuating asymmetry for dental arch variables were the highest in Class III, and lowest in Class I malocclusion. Males displayed a higher degree of asymmetry than females. The asymmetry degree was higher in the mandibular dental arches than in the maxillary dental arches in all malocclusion groups.ConclusionThe TWA values were low but they differed significantly between the groups of malocclusion. Class III malocclusion displayed higher FA values than Class I and Class II malocclusion. Higher FA of dental arches in Angle’s Class III can be considered an indicator of increased developmental instability in this malocclusion due to high levels of genetic and environmental stress during the period of early development.

Biodiversity effects on ecosystem functioning respond unimodally to environmental stress.

Understanding how biodiversity (B) affects ecosystem functioning (EF) is essential for assessing the consequences of ongoing biodiversity changes. An increasing number of studies, however, show that environmental conditions affect the shape of BEF relationships. Here, we first use a game-theoretic community model to reveal that a unimodal response of the BEF slope can be expected along environmental stress gradients, but also how the ecological mechanisms underlying this response may vary depending on how stress affects species interactions. Next, we analysed a global dataset of 44 experiments that crossed biodiversity with environmental conditions. Confirming our main model prediction, the effect of biodiversity on ecosystem functioning tends to be greater at intermediate levels of environmental stress, but varies among studies corresponding to differences in stress-effects on species interactions. Together, these results suggest that increases in stress from ongoing global environmental changes may amplify the consequences of biodiversity changes.

Planning from the Margin—The European Union’s Potential Role in Spatial Planning for Managing Activities in the Marine Arctic

Abstract The Arctic is subject to increasing levels of human activities and environmental stresses. The need to protect Arctic ecosystems and utilize the region’s resources sustainably necessitates effective and coordinated management of human activities. A potentially important instrument is marine spatial planning (MSP). The article analyses the potential of the European Union (EU) to contribute to the development and implementation of MSP, or related instruments, in the marine Arctic. Although we conclude that EU law relevant to MSP currently has very limited applicability in the region, either directly or through the so-called EEA EFTA States, there are still ways in which the EU may contribute to making activities in the marine Arctic more sustainable. In this context, the EU’s new ‘policy for the Arctic’ could be an important instrument, but it will not by itself affect the region’s development or even guarantee concerted action by the EU Member States.

Patterns of herbivory and leaf morphology in two Mexican hybrid oak complexes: Importance of fluctuating asymmetry as indicator of environmental stress in hybrid plants

Interspecific hybridization is a prevalent process in plant species that may have different ecological and evolutionary consequences. Interactions with herbivorous insects may be altered because of hybridization among host plants. These changes result from the morphological, physiological and chemical traits expressed in hybrid individuals. Therefore, it is of interest to document the changes in traits such as leaf morphology and their consequences on patterns of herbivory by insects in hybrid complexes of plants. Another useful indicator that may serve to evaluate developmental instability resulting from genetic or environmental stress in hybrid plants is fluctuating asymmetry. In this study, we used two previously genetically characterized complexes of hybridizing Mexican oaks as models to compare and understand the relationships between leaf morphology, fluctuating asymmetry and herbivory levels in parental and hybrid individuals. Results indicated that in the Quercus affinis × Q. laurina complex, hybrid individuals show a distinct morphology in relation to the parental species, while in the Q. magnoliifolia × Q. resinosa complex, hybrids were similar to Q. resinosa. In both hybrid complexes, our results show that hybrid individuals have higher levels of fluctuating asymmetry and herbivory levels, which may reflect higher levels of genetic or environmental stress in comparison to the parental species. These results might help explain why oak species usually remain distinct despite the high frequency of hybridization characteristic of the genus.

Expression patterns of SRB1 and other stress-related genes in Candida albicans under oxidative, hyperosmotic and thermal stress.

Candida albicans, a human fungal pathogen, is able to tolerate certain levels of environmental stresses. Its cell wall plays an important role in cellular homeostasis, responding to environmental stimuli. SRB1 gene encodes a GDP-mannose pyrophosphorylase that catalyzes the formation of the major cell wall component, mannan. The exact relationship between SRB1 and various stresses is not yet fully understood. In current study, C. albicans SC5314 cells were exposed to oxidative, hyperosmotic, and thermal stresses. The expression of SRB1 and related stress response genes, HOG1, CAP1, MKC1, and HSP90, was systematically evaluated in cells exposed to various levels of stress. In addition, the apoptosis and ultrastructural changes of the cells were examined. We found that the expression of SRB1 and related stress response genes significantly increased under oxidative, hyperosmotic, and thermal stresses, and the increased gene expression was correlated with higher percentages of apoptosis and ultrastructural changes in C. albicans cells. We propose that protein glycosylation is associated with stress response that involves SRB1 in C. albicans. Further in-depth studies of SRB1 function should aid our understanding of C. albicans pathogenesis, and provide important clues about the development of novel antifungal compounds for drug resistant C. albicans.

Stomatal traits in Iberian populations of Osmunda regalis (Osmundaceae, Polypodiopsida) and its relationship with bioclimatic variables

Stomata are very conservative structures in plants, which allows and control the gas exchange. This ecophysiological fact appear to be critical in the ecology and adaptation of plants to environment. Plant individuals can, among other issues, adjust size and density of the stomata to adapt themselves to hydric, thermic and light regimes. In turn, this led to the reduction of transpiration and control of water losses, which is crucial in areas with Mediterranean climate. The fern Osmunda regalis have populations in both biogeographical regions of the Iberian Peninsula (Eurosiberian and Mediterranean regions), but when locations are highly continental the populations are scarce and isolated. The objective of this study is to characterize the stomatal morphological traits in both regions, to detect possible adaptations in individuals occurring in Mediterranean locations. 26 individuals of 17 different populations were sampled. Applying microscopic techniques, 4447 observations of length and width, and 234 of density and PCI were done. The sampling spots were characterized by two bioclimatic indices of Emberger and Gorzynski, and also mean maximum and minimum temperature values were obtained. All the information was included in a dataset that was statistically analyzed with the software SPSS. Our results show that Osmunda regalis fronds have higher PCI and density values in the Eurosiberian region, as expected. Gorczynski continentality index (K), and the mean maximum and minimum annual temperatures influences over stomatal traits. This is clearly informing that in the Mediterranean region, the temperature is an important factor that triggers stomatal adaptations of O. regalis to continental locations with higher levels of environmental stress. On the contrary, Emberger pluviometric index (Q) seems to be less explicative by its own. Perhaps this is related with the habitat of O. regalis in soils with high freatic level, fact which could lead to a more independent stomata from rainfall

Stomatal traits in Iberian populations of Osmunda regalis (Osmundaceae, Polypodiopsida) and its relationship with bioclimatic variables

Stomata are very conserved structures in plants, which allows and control the gas exchange. This ecophysiological fact appears to be critical in the ecology and adaptation of plants to environment. Plant individuals can, among other issues, adjust size and density of the stomata to adapt themselves to hydric, thermic and light regimes. In turn, this led to the reduction of transpiration and control of water losses, which is crucial in areas with Mediterranean climate. The fern Osmunda regalis has populations in both biogeographical regions of the Iberian Peninsula (Eurosiberian and Mediterranean regions), but when locations are highly continental the populations are scarce and isolated. The objective of this study is to characterize the stomatal morphological traits in both regions, to detect possible adaptations in individuals occurring in Mediterranean locations. 26 individuals of 17 different populations were sampled. Applying microscopic techniques, 4447 observations of length and width, and 234 of density and PCI were done. The sampling spots were characterized by two bioclimatic indices of Emberger and Gorzynski, and also mean maximum and minimum temperature values were obtained. All the information was included in a dataset that was statistically analyzed with the software SPSS. Our results show that Osmunda regalis fronds have higher PCI and density values in the Eurosiberian region, as expected. Gorczynski continentality index (K), and the mean maximum and minimum annual temperatures influences over stomatal traits. This is clearly informing that in the Mediterranean region, the temperature is an important factor that triggers stomatal adaptations of O. regalis to continental locations with higher levels of environmental stress. On the contrary, Emberger pluviometric index (Q) seems to be less explicative by its own. Perhaps this is related with the habitat of O. regalis in soils with high freatic level, fact which could lead to a more independent stomata from rainfall.

The Level of Academic and Environmental Stress among College Students: A Case in the College of Education

Stress that can arise from various academic and environmental aspects is very common among college students. Uncontrollable stress lowers academic, social, environmental, psychological and physical adjustment. In this research, the level of academic and environmental stress among College of Education (CoE) in EIT was intensively discovered. It was explored in relation to the students’ cumulative GPA and gender. The major academic and environmental factors that contribute to more stress among the college students was of a great interest in the study. Moreover, investigating the stress management strategies practiced by the college students was among the main concerns. To obtain a reliable data, a total of 107 students of 2nd, 3rd, and 4th year of the College of Education were randomly and conveniently selected to fill the self-developed questionnaire and in the focus group discussion. The data were analysed with the help of descriptive and inferential statistical techniques. The data computation process was assisted by a Software Package for Social Sciences (SPSS). The study findings reveal that majority of the College of Education students experience a moderate level of academic and environmental stress. Gender and Cumulative GPA of the students were also found not to have statistically significant difference. However, CGPA was merely found to have a slight statistically significant relationship with the level of environmental stress. Majority of the students expressed as they practice various positive stress management strategies. The study is expected to contribute a lot in assessing the level of stress and identifying the most stressful academic and environmental factors.

Modeling the decline of labor-sharing in the semi-desert region of Chile

The rapid environmental changes currently underway in many dry regions of the world, and the deep uncertainty about their consequences, underscore a critical challenge for sustainability: how to maintain cooperation that ensures the provision of natural resources when the benefits of cooperating are variable, sometimes uncertain, and often limited. In this work, we present the case of a group of rural communities in a semi-desert region of Chile, where cooperation in the form of labor-sharing has helped maintain higher agriculture yields, group cohesion, and identity. Today, these communities face the challenge of adapting to recurrent droughts, extreme rainfall, and desertification. We formulated an agent-based model to investigate the consequences of regional climate changes on the fate of these labor-exchange institutions. The model, implemented in the framework of prospect theory, simulates the economic decisions of households to engage, or not, in labor-sharing agreements under different scenarios of water supply, water variability, and socio-environmental risk. Results show that the number of fulfilled labor-sharing agreements is reduced by water scarcity and environmental variability. More importantly, defections that involve non-fulfillment of these agreements are more likely to emerge at the intermediate level of environmental variability and water supply stress. These results underscore the need for environmental policy instruments that consider the effects of regional climate changes on the social dynamics of these communities.

Impact of the Late Triassic mass extinction on functional diversity and composition of marine ecosystems

AbstractMass extinctions have profoundly influenced the history of life, not only through the death of species but also through changes in ecosystem function and structure. Importantly, these events allow us the opportunity to study ecological dynamics under levels of environmental stress for which there are no recent analogues. Here, we examine the impact and selectivity of the Late Triassic mass extinction event on the functional diversity and functional composition of the global marine ecosystem, and test whether post‐extinction communities in the Early Jurassic represent a regime shift away from pre‐extinction communities in the Late Triassic. Our analyses show that, despite severe taxonomic losses, there is no unequivocal loss of global functional diversity associated with the extinction. Even though no functional groups were lost, the extinction event was, however, highly selective against some modes of life, in particular sessile suspension feeders. Although taxa with heavily calcified skeletons suffered higher extinction than other taxa, lightly calcified taxa also appear to have been selected against. The extinction appears to have invigorated the already ongoing faunal turnover associated with the Mesozoic Marine Revolution. The ecological effects of the Late Triassic mass extinction were preferentially felt in the tropical latitudes, especially amongst reefs, and it took until the Middle Jurassic for reef ecosystems to fully recover to pre‐extinction levels.