Displacement Instability Research Articles

Environmental displacement and political instability: Evidence from Africa

Does environmental displacement provoke political instability? Though migration has long been considered an intermediary in the causal path between environmental change and political upheaval, the relationship remains theoretically underdeveloped and evidence has been limited. This article examines the impact of displacement caused by sudden-onset natural hazards on disruptive antigovernment events including armed conflict, protests and violent riots. It leverages the new Environmental Displacement Dataset (EnDis), an original dataset that identifies quantities of human movement in response to six types of sudden-onset natural hazards in Africa from 1990 to 2017, including floods, storms, wildfires, landslides, earthquakes and volcanic activity. The results of the analyses show that while environmental displacement is not associated with civil war onset or protests, it does increase the incidence of attacks by armed non-state actors and violent riots. Importantly, these destabilizing effects occurr primarily (1) in the context of displacement driven by floods and storms, and (2) when levels of displacement are well above average. Collectively, these findings portend deepening security crises and violent political upheaval as climate change drives more frequent episodes of extreme weather and excessive environmental displacement.

Research on coal wall failure and stability control technology of large coal seams with a soft and thick seam

AbstractTo address the issues of coal rib instability and high occurrence of roof falls in high extraction height fully mechanized coal mining of soft coal seams, this study comprehensively employs theoretical analysis, numerical calculations, and field industrial experiments. By analyzing the distribution characteristics of coal rib displacement and deformation instability zones under different mechanical parameters of soft coal seams, the instability mechanism of coal ribs in high extraction height mining of thick and soft coal seams is revealed, and corresponding stability control techniques for high extraction height coal ribs and supports are developed. The study shows that the stability of coal ribs in high extraction height mining fields of soft and thick coal seams decreases as the values of mechanical parameters decrease. In other words, the smaller the cohesion and deformation parameters of the coal body, the more prone the coal rib is to roof falls. By utilizing advanced deep‐hole static water infusion technology, the frequency of roof falls in extremely soft high extraction height working faces is reduced by 80%, the average depth of roof falls is decreased by 35%, and the average length of roof falls is reduced by 50%. The stability of the coal ribs is effectively improved.

Influence of Anterior Talofibular Ligament Injury and Ankle Anterior Displacement on Symptoms in Individuals With Chronic Ankle Instability.

Repeated ankle sprains can lead to injuries, including those of the anterior talofibular ligament (ATFL); however, the extent to which these ligament injuries are associated with symptoms of chronic ankle instability (CAI) remains unclear. To examine the influence of ATFL injury and ankle anterior displacement on symptoms of CAI. Case-control study. University laboratory. A total of 122 of 426 college students who completed a questionnaire on the history of ankle sprain were enrolled in healthy (n = 34; 24 men, 10 women; age = 20.6 ± 0.5 years), coper (n = 49; 38 men, 11 women; age = 20.2 ± 1.2 years), and CAI groups (n = 39; 24 men, 15 women; age = 20.1 ± 1.1 years). One examiner measured the ATFL delineation using ultrasound and anterior ankle displacement using a capacitance-type sensor device. The Cumberland Ankle Instability Tool was applied to assess pain and perceived instability. The ATFL was normal more frequently in the healthy group and abnormal more frequently in the CAI group (χ2 = 18.45, P < .001). Anterior ankle displacement was greater in the coper and CAI groups than in the healthy group (both, P < .001), but no difference was observed between the coper and CAI groups (P = .16). We observed no correlation between the anterior ankle displacement and Cumberland Ankle Instability Tool scores (r = -0.004, P = .71) in participants with previous ankle sprains. Observation of an abnormal ATFL on ultrasonography was associated with anterior displacement of the ankle joint. However, the influence of anterior ankle displacement due to damage to the ATFL on the pain and perceived instability in CAI was assumed to be small.

Momentum transport of morphological instability in fluid displacement with changes in viscosity.

Saffman-Taylor instability exhibits a stepwise unstable morphology from a stable interface to viscous fingering, eventually leading to tip splitting. The nonlinear dynamics of the destabilized interface depends on various flow properties. However, the physicochemical mechanism that determines the transition point of the flow state is unclear. We studied the interfacial instability transition in miscible displacement from a thermodynamic perspective by calculating the momentum transport and entropy production. Using numerical analysis based on Darcy's law coupled with the convection-diffusion equation, the observed flux-dependent flow state transitions were attributed to the selection of the flow state with a higher entropy production.

Step-like displacement prediction and failure mechanism analysis of slow-moving reservoir landslide

Landslides triggered by extreme rainfall due to global climate change are becoming more frequent. The Earth surface processes activity and landform evolution caused by landslide movement seriously affect human survival and the environment. In recent years, the reservoir slope located in the Three Gorges reservoir (TGR) area has been subject to the combined effects of extreme rainfall and reservoir regulation, which have been highly susceptible to inducing landslides. Reservoir landslides usually show step-like slow movement characteristics. The causes of slow-moving landslides are complex, the mechanisms behind them are difficult to grasp, and it may evolve into violent landslide disasters. Therefore, accurately predicting step-like displacement in slow-moving landslides is an effective solution for risk reduction. To achieve the accurate prediction of the step-like displacement of slow-moving landslides and the analysis of the failure mechanism, this study establishes a prediction model applicable to step-like displacement prediction of slow-moving reservoir landslides is developed based on 16 years of continuously monitored cumulative displacement of the Jiuxianping landslide, combined with the Empirical Mode Decomposition (EMD) method and the Improved Particle Swarm Optimization (IPSO) optimized the Long short-term memory (LSTM) neural network. This approach can effectively improve step-like displacement prediction accuracy. In particular, this approach can better represent the association between the step displacement of slow-moving landslides with environmental characteristics (e.g., rainfall, reservoir level). The study reveals that there are differences in the mechanisms and influencing conditions that cause the deformation of different areas of the landslide. Additionally, the reservoir water level fluctuation and seasonal rainfall are identified as the primary reasons contributing to the stepped displacement of the Jiuxianping landslide. The method provides a basis for the step-like displacement prediction, instability mechanism and landform evolution study of slow-moving reservoir landslides and provides valuable guidance for the prevention and control of similar reservoir geomorphic hazards worldwide.

Evaluation of heterogeneity effect on CO2 transport in regularly distributed and natural clast-matrix conglomerate cores

A series of numerical simulations were performed to investigate the heterogeneity effect resulting from spatial distribution of clast-matrix in conglomerates on CO2 migration under the reservoir conditions. Natural conglomerate cores drilled from geological CO2 storage site in South Korea as well as constructed cores comprising regularly distributed clast-matrix were numerically analyzed. Throughout the study, CO2 distribution, velocity of the CO2 front, breakthrough curves (BTCs), differential pressure (ΔP), gravity number (Ngv), and capillary number (Nc) were assessed to highlight the heterogeneity effect. In the regularly distributed clast-matrix cores, the CO2 plume with the corrugated shape of the front migrated faster than the matrix-only core. Even though the clast ratio was changed more than 10 %, there was not much difference in the arrival velocity of the CO2 plume (∼2.0×10−4 m/min). Nevertheless, there was a correlation between the clast ratio and the arrival velocity, clearly shown in the L-5 core having alternating layers of matrix and clasts. At natural conglomerate cores (JC-1 and JC-2), the migration pattern of the CO2 plume significantly differed. However, the clast-matrix ratio and the arrival velocity were strongly correlated with a large variation in the arrival velocity (∼2.6×10−3 m/min) despite the small change of the clast-matrix ratio. The variance of the cumulative arrival velocity was correlated with the clast-matrix ratio and the irregularity of the BTCs, which implied that the instability in the frontal displacement of the CO2 plume became greater where the clast ratio increased more. The ΔP was significantly affected by the distribution of clasts and matrix; ΔP increased as the CO2 passed narrow or heterogeneous pathways enclosed by the clasts and decreased as CO2 passed wide or diverging pathways. Interestingly, the highest ΔP was shown in the cores having the smallest clast ratio, implied that the heterogeneous distribution of clast-matrix could influence a degree of overpressure generation. The lowest Ngv below 1 and highest Ngv appear in JC-2 where the total clast ratio is more than 50 % and in H-1 consisting of matrix-only, respectively. The obtained ranges of Nc show that all the models are under capillary-dominated flow conditions relevant for CO2 sequestration. The magnitude of both Ngv and Nc correlates to the total clast ratio.

Influence of two-phase displacement characteristics on the storage efficiency and security of geological carbon storage

In the mitigation of greenhouse gas emissions, the storage efficiency and security of geological carbon storage (GCS) are the focus of attention, and both of them are closely related to the displacement behavior between immiscible two phases. In this study, CO2-water two-phase displacement experiments were conducted on six samples with various pore structures using nuclear magnetic resonance and magnetic resonance imaging technology to characterize the fluid distribution and determine displacement patterns. The displacement property was found to be closely related to the heterogeneity and anisotropy of pore structure. The two-phase displacement instability gradually evolved from tonguing (logCa > −2.94) to capillary fingering (logCa < −2.03), and then further evolved into viscous fingering (logCa > −2.03). Nevertheless, rocks with good connectivity and high permeability will restrain the occurrence of unstable displacement even if logCa is in the favorable range. Combined analyses of displacement patterns and pore structure can provide effective means for the evaluation of reservoir and caprock. For rocks dominated by micropores, their displacement pattern is more likely to correspond to time-consuming piston-like displacement. Their high sealing efficiency is characterized by high capillary displacement pressure and low effective gas permeability, which allow them to be considered as caprocks. For rocks with lower capillary displacement pressure and higher effective gas permeability, their lower residual water saturation makes them more suitable as favorable reservoirs for GCS. Reservoir rocks with stable piston-like displacement exhibit the highest displacement efficiency, while the difference of displacement rates in pores with diverse sizes caused by the fingering or tonguing phenomena weakens the displacement efficiency.

Effect of sinusoidal injection velocity on miscible viscous fingering of a finite sample: Nonlinear simulation

The effect of a sinusoidal injection on the fingering instability in a miscible displacement in the application of liquid chromatography, pollutant contamination in aquifers, etc., is investigated. The injection velocity, U(t) is characterized by its amplitude of Γ and time-period of T. The solute transport, flow in porous media, and mass conservation in a two-dimensional porous media is modeled by the convection-diffusion equation, Darcy's equation, and the continuity equation, respectively. The numerical simulation is performed in COMSOL Multiphysics utilizing a finite-element based approach. The fingering dynamics for various time-period have been studied for two scenarios namely, injection-extraction (Γ>1) and extraction-injection (Γ<−1). The onset of fingers and vigorous mixing is observed for Γ>1, whereas for Γ<−1, the onset gets delayed. The viscosity contrast between the sample and the surrounding fluid is characterized by the log-mobility ratio R. When R>0 the rare interface becomes unstable, while for R<0 the frontal interface deformed. In the case of R<0, the extraction-injection process attenuates the fingering dynamics, which is beneficial in chromatographic separations or pollutant dispersion in underground aquifers. The injection-extraction process is observed to have a longer mixing length, indicating early interaction between both interfaces. The degree of mixing χ(t) is more pronounced for injection-extraction scenario and least for extraction-injection R<0,Γ=−2. The average convective forces are more dominant for Γ>1,R=2 till the deformed rare interface interact with diffusive frontal interface. The average diffusive forces are significant for Γ<−1,R=−2 which can be helpful in separation of chemicals in chromatography. This study therefore provided new insights into the role of alternate injection-extraction injections in altering the fingering dynamics of the miscible sample.

Investigation of morphological, structural and electronic transformation of PVDF and ZnO/rGO/PVDF hybrid membranes

Synergistic doping of 2-D Material ZnO nanosheets and reduced graphene oxide (rGO) of Polyvinylidene fluoride (PVDF), PVDF/ZnO, and PVDF/ZnO/rGO Hybrid membranes simply by solution casting technique for raising electronically favored β-phase ratio. Rietveld refinement X-ray diffraction technique, FTIR, Microscopic investigation, SEM, and density-functional theory (DFT) calculations were employed to unravel the atomistic origin of negative piezoelectricity, and increasing reasons for total dipole moment, electrostatic potential and bandgap energy of PVDF hybrid membranes, which arises from the sizeable displacive instability of two-dimensional material coupled with its reduced lattice dimensionality.

Lagrangian Numerical Simulation of Proppant Transport in Channel Fracturing

This paper focuses on the numerical simulation of particle (“proppant”) transport in channel fracturing, in which fiber-proppant fluid is pumped intermittently into hydraulic fractures, alternated with clean fluid pulses. The pulsed pumping protocol leads to heterogeneous/channelized proppant distribution in fractures, generating open flow channels with high conductivity. To understand the evolution of the channelized proppant distribution, we develop an efficient pseudo-3D multiphase particle-in-cell (P3D MP-PIC) method to simulate the proppant transport during the pumping process. Compared with the Eulerian-Eulerian (EE) models, the MP-PIC approach has higher accuracy in modeling particle-fluid and particle-particle interactions by tracing the particles in a Lagrangian fashion. Compared with the computational fluid dynamics-discrete element method (CFD-DEM), the MP-PIC method is more computationally efficient due to a parcel feature and the fast calculation of particle forces. Reduced from the 3D MP-PIC method, the P3D MP-PIC method has better computational efficiency and flexibility to couple with other subsurface processes (e.g., fracture propagation and fluid leakoff) while also achieving sufficient accuracy for engineering purposes. Due to the Eulerian-Lagrangian (EL) nature, the P3D MP-PIC method can track the trajectories of the fiber-proppant clusters whose effective viscosity and the settling velocity are determined based on the laboratory results. With an accurate description of fluid and particle dynamics, this work reveals the critical physical mechanisms of the proppant transport in channel fracturing: stable displacement and Saffman-Taylor (ST) instability. The alternate occurrence of these two mechanisms gives rise to the channelized proppant distribution. To investigate the influential factors of the channel patterns, we conduct parametric studies on the operational parameters, including injection rate, fiber concentration, and pulsing mode. The effect of fracture propagation and gravitational settling is also discussed in detail.

Lateral Stress Radiographs of Lateral Compression Type 1 Pelvic Injuries, With the Injured Side Down or Up, Reliably Measure Occult Instability.

To evaluate the interobserver reliability of measured displacement and occult instability of minimally displaced lateral compression type 1 (LC1) fractures on lateral stress radiographs (LSRs) and to compare differences in displacement between LSR with the injured side down (ID) and up (IU). Retrospective review. Urban Level 1 trauma center. Twenty-three adult patients with minimally displaced (&lt;1 cm) LC1 injuries. None. Three orthopaedic surgeons measured the distance between the radiographic teardrops on LSR and supine anteroposterior pelvic radiographs to calculate dynamic fracture displacement. The interobserver reliability of the measured displacement, a continuous variable, was assessed by calculating the intraclass correlation coefficient. The interobserver reliability of occult instability (≥10 mm of displacement on LSR), a categorical variable, was assessed by calculating the kappa value. Matched-pairs analysis was performed to calculate the mean difference of measurements between observers and between ID and IU LSR. The interobserver reliability of the measured displacement was excellent (intraclass correlation coefficient 0.93). The mean difference in measurements between observers ranged from -1.8 to 0.96 mm. The mean difference in the measured displacement between ID and IU LSRs for each observer ranged from -0.6 to 0.3 mm. There was 83% (19/23 cases) agreement on the presence of occult instability (≥10 mm of displacement on LSR) on both ID and IU LSRs. The interobserver reliability of occult instability was moderate (kappa 0.76). Measured fracture displacement and occult instability of minimally displaced LC1 injuries were reliably measured and identified on LSR, regardless of the laterality.

Accelerated Movements of Xiaomojiu Landslide Observed with SBAS-InSAR and Three-Dimensional Measurements, Upper Jinsha River, Eastern Tibet

Many ancient landslides in the upper reaches of the Jinsha River seriously threaten the safety of residents on both sides of the river. The river erosion and groundwater infiltration have greatly reduced the stability of the ancient landslides along the Jinsha River and revived many large landslides. Studying their deformation characteristics and mechanisms and predicting possible failure processes are significant to the safety of residents and hydropower projects. We used SBAS-InSAR and three-dimensional decomposition techniques in our study. Our results showed that the trailing edge and middle part of the landslide have rapidly deformed. The maximum vertical annual displacement rate was 12 cm/a period from July 2017 to July 2019. Correlation analysis showed that creep deformation is closely related to the river damming of the Baige landslide events and that the rising river level was an important factor in the resurrection and accelerated destruction of the Xiaomojiu landslide. As a result, we predicted the possible failure process of the Xiaomojiu landslide, which might have lasted 80 s and eventually formed a landslide deposit with a height of about 150 m, a length of approximately 1500 m, and an average width of 450 m. Our results provide data references for displacement monitoring and instability risk simulation of large landslides along the Jinsha River.

Experimental study on the role of polymer addition in Saffman–Taylor instability in miscible flow displacement

The role of nonlinear rheology of polymeric fluids in finger formation and the ensuing morphology of the patterns in miscible flow displacement is examined experimentally. The poly(ethylene oxide) (PEO) is introduced in either displaced or displacing fluid. The PEO solutions exhibit shear-thinning viscosity as well as normal stresses. As viscous fingering is primarily caused by the viscosity contrast between two miscible fluids, the zero-shear viscosities of the two fluids are controlled mainly by their composition. The contribution of rheological behavior in fingering is studied by varying the molecular weight of the polymer. The development of fingering patterns in PEO solutions is observed to be more complex showing more branches and tip-splitting vis-à-vis Newtonian fluid even for the same value of effective viscosity contrast regardless of polymer addition in either fluids. Particularly, flow displacement with displaced PEO solution exhibits significantly intensified patterns such that a fractal-like growth is observed when PEO solution of either high concentration or high molecular weight is being displaced. The additional nonlinear behavior, sidebranching, tip-splitting, and shielding is attributed to the inhomogeneity in fluid viscosity and normal stresses (or elasticity) due to local flow behavior. While shear-thinning behavior promotes the longitudinal growth of fingers leading to the shielding effect, the presence of normal stresses inhibits longitudinal growth of fingers promoting fingers in the transverse direction that imparts tip-splitting. Overall, the nonlinear rheology of the fluids gives rise to the effects, in addition to the viscosity modifications, and hence, is crucial for determining the morphology of the fingering instability.

Disasters, Displacement, and Housing Instability: Estimating Time to Stable Housing 13 Years after Hurricane Katrina

Abstract Catastrophic disasters disrupt the structural and social aspects of housing, which can lead to varying lengths of displacement and housing instability for affected residents. Stable housing is a critical aspect of postdisaster recovery, which makes it important to understand how much time passes before displaced residents are able to find stable housing. Using the Gulf Coast Child and Family Health Study, a longitudinal cohort of Mississippi and Louisiana residents exposed to Hurricane Katrina (n = 1079), we describe patterns of stable housing by identifying protective and prohibitive factors that affect time to stable housing in the 13 years following the storm. Survival analyses reveal that median time to stable housing was 1082 days—over 3 years after Katrina. Age, housing tenure, marital status, income, and social support each independently affected time to stable housing. Findings suggest that postdisaster housing instability is similar to other forms of housing instability, including eviction, frequent moves, and homelessness. Significance Statement Climate change is expected to increase gradual-onset events like sea level rise, as well as the frequency and intensity of acute disasters like hurricanes. Such events when coupled with population growth, coastline development, and increasing inequality will lead to high levels of displacement and housing instability. Using longitudinal data, we wanted to understand how much time passed until residents who were displaced by Hurricane Katrina were able to find permanent and stable housing and identify factors that either prolonged or accelerated respondents’ time to stable housing. Addressing this gap can help to improve resident recovery and create targeted postdisaster housing policy, especially as displacement from disasters becomes increasingly common among those living in regions susceptible to the effects of climate change.

The concept design of the upgrade of EAST in-vessel second-generation fast control power supply

The elongated plasma has vertical displacement instability, which could be retrained by active control. The topology of the second-generation fast control power supply is three-phase uncontrolled rectification and H-bridge inverter structure, which can achieve fast response (less than 1 ms) and large rated current (6 kA). But the power supply requires to further improve the power quality and achieve the recuperation of braking energy. The main topology is optimized. This paper will introduce the optimized fast control power supply that adopted three-phase voltage source PWM rectifier. The simulation and experiment results show the correctness of the theoretical analysis and provide the technical reference for the vertical stability fast power supply in other Tokamak devices.

Impact of gravity and inertia on stable displacements of DNAPL in highly permeable porous media

The flow of Dense Non-Aqueous Phase Liquid (DNAPL) in highly permeable porous media is characterized by a complex interplay between surface tension, viscous, gravity, and inertia forces. Gravitational effects in these systems have been particularly studied in the context of displacement instability, but little work has focused on the impact of gravitational and inertia forces on the stable displacement of DNAPL in highly permeable but non-fractured porous media. Here, we study the impact of the gravity and Forchheimer numbers on the stable displacement of DNAPL fronts in porous media. We first performed DNAPL injection experiments in bead packings of different sizes for different inlet flow rates and initial saturation. These experiments were accurately modeled using a Darcy–Forchheimer model combined with an Arbitrary Lagrangian–Eulerian tracking of the DNAPL front. Once validated against stable injections in glass beads, the model was then used to perform a broader parametric study than available with our experimental setup. We explored different injection and pumping scenarios over a range of dimensionless numbers. We found that gravity can significantly alter the fluid front in flows commonly found in contaminant hydrology. We estimate, however, that inertia will have a non-negligible impact upon the displacement of DNAPL only during active remediation techniques (e.g., free product pumping method) or pipe rupture events involving low-viscous DNAPL in highly-permeable porous media.

Flexible Fixation Technique for Subtle Lisfranc Injuries

Background: Subtle Lisfranc injuries represent a primarily ligamentous Lisfranc complex injury involving the Lisfranc ligament and the medial and middle cuneiform ligaments. Static radiographic displacement or dynamic instability of the medial cuneiform and 2nd metatarsal typically warrants operative intervention to prevent chronic functional pain, allow for timely return-to-sport, and mitigate posttraumatic osteoarthritis. Flexible fixation techniques offer a unique solution to the issues seen with transarticular screws, plates, and arthrodesis for ligamentous Lisfranc injuries. Indications: We present the case of a 16-year-old female basketball player with a subtle Lisfranc injury sustained during practice. X-rays show isolated widening of the 1st and 2nd metatarsal bases and dynamic diastasis between the medial and middle cuneiforms. Magnetic resonance imaging (MRI) confirmed a rupture of the plantar Lisfranc ligament. After extensive discussion regarding treatment options, the patient and her family decided to proceed with surgical intervention using a suture anchor and button technique to restore stability to the Lisfranc ligament and intercuneiform complexes. Technique Description: A standardized dynamic examination under anesthesia identifies the extent of the injury. Exposure of the base of the 2nd metatarsal and medial cuneiform is performed. Reduction clamps are applied to restore the intercuneiform relationship and interval between the medial cuneiform and base of 2nd metatarsal. The suture anchor and button construct is placed using fluoroscopic guidance. A final dynamic examination is performed to confirm stability of the construct. Results: Biomechanical studies have shown that flexible fixation maintains physiologic motion about the Lisfranc articulations and has comparable stability to transarticular screws in cadaveric models of isolated Lisfranc ligament insufficiency. Clinical results are limited but demonstrate excellent postoperative functional outcome scores with very few fixation-related complications at 1 to 3 years. Discussion: Flexible fixation techniques for subtle Lisfranc injuries offer unique benefits to transarticular screws, plates, and arthrodesis. We highlight the appropriate evaluation of patients with a suspected subtle ligamentous Lisfranc injury, the surgical technique using a suture button and anchor construct, and review postoperative management and expected outcomes based on the present literature.

Understanding the interplay of capillary and viscous forces in CO2 core flooding experiments

Interaction between capillary and viscous forces significantly affects the flow instability in immiscible displacement, which is usually investigated by visualization of flow patterns in 2d porous micromodels or in 3d system equipped with X-ray CT. However, in most practical applications, visualization of flow in porous media is not possible and the pressure signal is often as one of the important sources of information. Core flooding experiments were implemented in this study to investigate the interplay of capillary and viscous effects by analysis of differential pressure. Water and crude oil were employed as defending fluid, and different states of CO2 were injected as invading fluid. The inlet was set as the constant injection flow rate while the outlet as the constant pressure. In viscous-dominated displacement, differential pressure evidently depends on the injection rate and the pressure decline curve is fitted by a power function. The exponent of the function is found to be significantly larger at the crossover between capillary-dominated and viscous-dominated regions. In capillary-dominated displacement, the pressure profile is characterized by a pressure jump at the beginning and intermittent fluctuations during the displacement. Further analysis by wavelet decomposition indicates a transition point existing in standard deviation of pressure fluctuations when the displacement is transformed from capillary-dominated to viscous-dominated. The experimental results are finally verified by a macroscopic capillary number, which characterizes the interaction between capillary and viscous forces at a critical value of Ncamacro∼1, agreeing well with the Log Nca-Log M phase diagram.

Reconnoitering school children vulnerability and its determinants: Evidence from flood disaster-hit rural communities of Pakistan

Children are disproportionately affected by disasters, in both the long and short term, particularly in developing countries. Children in rural areas face the most adversity since they are inadequately prepared, lacking in resources, and oblivious to their potential. Many children continue to turn to their parents or guardians for help in emergencies, however, the behavior, awareness, and preparedness of a child is equally important during an emergency. This paper takes a closer look at the physical, psychological, and educational vulnerabilities, as well as factors that influence the involvement of children in flood disaster-related activities (between 2010 and 2014) in selected disaster-hit rural communities of Pakistan. This study was based on interviews with a total of 100 school children from four selected regions and analysis was performed using univariate, bivariate, and multivariate methods. The study results show that school children in Nowshera are more susceptible to disasters than the other districts, particularly due to their psychological, physical, and educational well-being. Nowshera has the highest percentage of children who are vulnerable to all three types of vulnerability. Damage to homes and emotional distress are significant predictors of psychological vulnerability, while proximity to disaster-prone areas, poor diet, and parental loss are important contributors to physical vulnerability. Children displacement, delayed enrolment, multiple relocations, and family instability are the main factors determining educational vulnerability. Our findings suggest that in addition to having improved building infrastructure, schools must engage in disaster management efforts to educate school children about the risks of disasters.

Child health and wellbeing in a changing climate

Abstract Children are one of the most sensitive groups to climate change, along with the elderly and those in small island developing states, according to the Intergovernmental Panel on Climate Change. UNICEF estimates that more than half a billion children are estimated to live in extremely high flood risk areas. Children are vulnerable to both the sudden events linked to climate change (e.g., flooding, heatwaves, and wildfires) as well as slower-onset impacts (e.g., water scarcity, shifting agricultural zones, rising sea levels, and increasing disease-vector ranges). Climate change has enormous potential to undermine development gains and livelihood options for today's children. This presentation will provide an overview of impacts on child health and development of both the sudden climate change effects, including extreme weather events, extreme heat, and effects on natural systems; and consequences of the changing climate, such as displacement, migration, and social instability. The trauma of living through a climate-related disaster can have substantial mental health impacts on children and youth. Some key challenges towards to studying and modelling these impacts will be shared. Finally, action and commitments to protect children from climate change will be highlighted.