Search Results (3,597)

Pogo is identified as a deep-seated, intrusion-related gold deposit. Carbonate minerals have a close spatial relationship to hydrothermal gold mineralization in all of its principal ore zones. The carbon and oxygen isotopic ratios of carbonate minerals (siderite, ankerite, and calcite) present within the deposit illustrate the isotopic evolution of the ore-forming fluid. The initial hydrothermal fluid phase is interpreted to be magmatic in origin. The fluid evolution was characterized by a gradual decrease in δ¹⁸O and a slight increase in δ¹³C with decreasing temperature. The dominant carbon-bearing species was CO₂, with methane introduced sporadically. Siderite is associated with early-stage mineralization and occurs with ankerite in main-stage ore assemblages. Calcite is recognized in the later stages of mineralization. Gold in the Pogo deposit occurs as native gold, Au-Bi-Te minerals, inclusions in sulfide minerals, or as “invisible gold”. The latter is found in pyrite, chalcopyrite, arsenopyrite, and quartz, based on ion microprobe analysis. The presence of invisible gold in these minerals has significant metallurgical implications for gold processing at the Pogo mine. Full article

The formation of an aluminosilicate gel structure made of alkali-activated materials (AAMs) was conducted through an alkali-activation reaction of the solid precursors (fly ash, metakaolin, and wood ash). Fly and wood ash are by-products of the burning process of coal and wood, respectively. Alkali-activated materials of aluminosilicate origin, made from the different ashes, fly and wood, are very attractive research targets and can be applied in various technological fields due to their thermal stability, resistance to thermal shock, high porosity, high sustainability, and finally, low energy loss during production. In this paper, we evaluate physico-chemical properties, microstructure, and radiological environmental impacts when wastes that contain elevated levels of naturally occurring radionuclides (NORs) such as fly ash and wood ash are made into “green cements” such as AAMs. The determination of radionuclide content was performed by means of gamma-ray spectrometry. Results showed that the AAMs have a lower value in the activity concentration of radionuclides than raw materials. The external absorbed gamma dose rate was 74.7–107.3 nGy/h, and the external radiation hazard index values were in range of 0.445–0.628 Bq/kg. The results of the activity concentration measurements for alkali-activated materials indicate the potential of their safe application in building construction. In terms of the structural characterizations, the obtained alkali-activated materials were examined using XRD, DRIFT, FESEM, and TEM analyses. Full article

Malaysia can accurately analyse flood patterns and susceptible forecast areas and allocate resources as efficiently as possible by leveraging geographic information systems (GIS). Authorities can execute data-driven plans for robust flood control and quick catastrophe response because of this technology. However, in Malaysia, public authorities adequately apply GIS, researchers often limit the use of GIS applications to study natural disasters and communities find GIS challenging to learn and adopt. By producing flood risk mapping using GIS applications that make it easy for the communities to understand the situation, the government and communities can implement programs to mitigate the impacts of natural hazards. Reviewing the available literature on the use of GIS applications in assessing natural hazards, this study found that GIS applications effectively provide flood risk mapping and positively impact natural disaster management to ensure that the worst impacts of natural hazards can be avoided. Moreover, this study revealed the importance of GIS applications and technologies in managing natural hazards in communities to make them better prepared for disaster management. Based on the scientific research, 12 articles were identified to analyse flood management activities in Malaysia. Therefore, the government and relevant agencies should take advantage of the appropriate use of GIS in managing natural disasters and educate the population about applying GIS so that present and future generations can gain this knowledge earlier and use it better in mitigating disaster risks. Full article

Tourism and climate change have a two-way relation. Spatial planning can challenge this correlation, by making tourism destinations more resilient to climate change and tourism contributing less to the climate change acceleration. Based on literature review and theoretical research, this paper unravels the spatial structure of tourism destinations and presents systematically the way tourism affects—and is affected by—climate change. The objective of this paper is to articulate policy and planning recommendations and guidelines to address resilience against climate change at all destination scales. The paper identifies as most threatened the destinations facing extreme weather events, temperature fluctuations, and sea level rise (and more precisely the coastal and mountainous destinations), followed by areas facing water shortage and droughts, areas with fragile tourism resources (natural and cultural), and those experiencing overtourism. In regard to spatial planning for tourism (cross-cutting or sectoral), the paper argues that it has a proactive nature (making tourism destinations less vulnerable to climate change) but also can contribute to the earlier recovery of them after a disaster/damage has occurred. Spatial planning is also important for moderating the uncontrolled tourism growth responsible for climate change acceleration. A key conclusion is that a risk assessment and analysis should be an integral part of spatial tourism planning, focusing on the hazards and threats related to climate change. Full article

The skin, the largest organ of the human body, plays numerous essential roles, including protection against environmental hazards and the regulation of body temperature. The processes of skin homeostasis and ageing are complex and influenced by many factors, with epigenetic mechanisms being particularly significant. Epigenetics refers to the regulation of gene expression without altering the underlying DNA sequence. The dynamic nature of the skin, characterized by constant cellular turnover and responsiveness to environmental stimuli, requires precise gene activity control. This control is largely mediated by epigenetic modifications such as DNA methylation, histone modification, and regulation by non-coding RNAs. The present review endeavours to provide a comprehensive exploration and elucidation of the role of epigenetic mechanisms in regulating skin homeostasis and ageing. By integrating our current knowledge of epigenetic modifications with the latest advancements in dermatological research, we can gain a deeper comprehension of the complex regulatory networks that govern skin biology. Understanding these mechanisms also presents promising avenues for therapeutic interventions aimed at improving skin health and mitigating age-related skin conditions. Full article

The stability and diversity of the natural landscape is critical to maintaining the ecological functions of a region. However, ecosystems in the Yunnan section of the Tropic of Cancer face increasing pressure from climate change, human activities, and natural disasters, which significantly influence their vulnerability. Ecosystem vulnerability is determined by structural and functional sensitivity, coupled with insufficient adaptability to external stressors. While previous research has emphasized the effects of climate change, the multidimensional impacts of land use and human activities have often been overlooked. This study aims to comprehensively assess the ecological vulnerability of the Yunnan section of the Tropic of Cancer, addressing this research gap by utilizing geographic information system (GIS) technology and the Vulnerability Scoping Diagram (VSD) model. The study constructs a multidimensional evaluation index system based on exposure, sensitivity, and adaptive capacity, with a specific focus on the effects of land use, human activities, and natural disasters. Key indicators include road and population density, soil erosion, and geological hazards, along with innovative considerations of economic adaptive capacity to address gaps in previous assessments. The findings highlight that ecological vulnerability is predominantly concentrated in areas with low vegetation cover and severe soil erosion. Human activities, particularly road and population density, are identified as significant drivers of ecological vulnerability. Sensitivity is heavily influenced by soil erosion and geological disasters, while economic adaptability emerges as a critical factor in mitigating ecological risks. By proposing targeted policy recommendations—such as enhancing ecological protection and restoration, optimizing land use planning, and increasing public environmental awareness—this study provides actionable strategies to reduce ecological vulnerability. The findings offer crucial scientific support for improving the ecological environment in the Tropic of Cancer region and contribute to achieving sustainable development goals. Full article

Determining the ‘best-fitting’ distribution for data is an important problem in data analysis. Specifically, observing how the distribution of data changes as values below (or above) a threshold are omitted from analyses can be of use in various applications, from animal movement to the modelling of natural phenomena. Such truncated distributions, known as hazard functions, are widely studied and well understood in survival analysis, although rarely widely used in data analysis. Here, by considering the hazard and reverse-hazard functions, we demonstrate a qualitative assessment of the ‘best-fit’ distribution of data. Specifically, we highlight the potential advantages of this method when determining whether power-law behaviour may or may not be present in data. Finally, we demonstrate this approach using some real-world datasets. Full article

Coal mine water hazards are one of the five major natural disasters in mines, and water in depleted areas is the most serious form of water hazard causing casualties. The exploration of depleted areas, especially old tunnels, presents significant challenges, and achieving the required borehole density for exploration in depleted areas is difficult in reality. The authors of this paper previously applied for a patent titled “Water Injection Exploration Method for Depleted Areas Based on Stress Seepage Principle”. In order to theoretically analyze the feasibility of the patented results and validate them in practice, we first analyze the stress distribution and seepage phenomena around the goaf theoretically, construct boreholes underground in Renlou Coal Mine, conducting on-site water injection tests for different zones (depleted areas, old tunnels, and general boreholes), and perform transient electromagnetic observations during the water injection tests. A total of 355 sets of water injection flow rate and pressure data were obtained from different zones in three different boreholes; permeability coefficients were calculated based on the measured data, and relevant diagrams were drawn. Through the analysis of water injection test data and theoretical analysis, the following conclusions were drawn: there are disturbances and stress reduction zones around depleted areas (old tunnels), and when the equivalent normal stress induced by water injection pressure is greater than zero, the permeability of fractures will increase significantly. Whether it is a borehole aimed at depleted areas or old tunnels, it shows the characteristic that the closer the distance to the depleted areas (old tunnels) is, the smaller the water injection pressure, and the larger the permeability coefficient. When water is injected into the disturbance and stress reduction zones of the depleted areas (old tunnels), the water injection pressure can decrease from 9–10 MPa to 3–4 MPa, and the permeability coefficient may even increase in quantity value. The phenomena of pressure reduction and increased permeability during water injection are significantly observable, indicating that the water injection exploration method for depleted areas based on the stress seepage principle is feasible and has practical significance. Full article

The rapid growth of unconventional natural gas development (UNGD), also known as hydraulic fracturing, has raised concerns of potential exposures to hazardous chemicals. Few studies have examined the risk of childhood cancer from exposure to UNGD. A case–control study included 498 children diagnosed with leukemia, lymphoma, central nervous system neoplasms, and malignant bone tumors during the period 2010–2019 identified through the Pennsylvania Cancer Registry. Cases were matched to controls using Pennsylvania birth records. For each subject, a new overall UNGD exposure metric was calculated which incorporates both spatial (proximity) and temporal (duration) aspects of well activity. Conditional logistic regression models were used to estimate the risk of combined and individual cancers by overall UNGD exposure, and well proximity. Children with a higher overall UNGD exposure (3rd/4th quartiles) had an increased risk for the four malignancies combined [OR] 1.69 (95% CI 1.01, 2.82) and 1.79 (95% CI 1.00, 3.19) compared to non-exposed children. Overall, individuals living within 0.5 miles of a UNGD site were 3.94 times (95% CI 1.66, 9.30) more likely to develop a malignancy compared to non-exposed children and the risk of lymphoma within 0.5 miles and 0.5–1 miles was also elevated [ORs of 5.05 (95% CI 1.09, 23.39) and 7.71 (95% CI 1.01, 59.00), respectively] compared to non-exposed. Our study found that overall UNGD cumulative activity as well as a proximity to UNGD wells were associated with an increased risk of childhood lymphoma and overall childhood cancers combined. Full article

Flood incident management involves taking actions to save lives and reduce damages during a flood. Agent-based modelling tools have recently been developed to simulate the dynamic interactions between people and floodwater as a flood event unfolds. To date, these have only been applied in locations with a wealth of data, relying upon bespoke local or national datasets. Although informal settlements have a concentration of vulnerable people and are often more exposed to natural hazards, data availability is often limited, posing challenges for planning and implementing flood incident management actions. In this study, a model that was first applied in the UK is adapted and applied to simulate flood evacuations in Kibera, a densely populated informal settlement in Nairobi. Although data quality limits some of the model’s potential, the results reproduce patterns of observed behaviour. Evacuation shelters in the Northwest, North, and Northeast are shown to perform best. A major exit route to the South, a bridge crossing, and a river path are shown to be especially prone to congestion during evacuations. This paper reports on the first application of an agent-based model to an informal settlement, Kibera. The demonstration is an important step towards an operational tool for flood incident management planning in informal settlements around the world. Full article

The use of satellite imagery for surface deformation monitoring has been steadily increasing. However, the study of extracting deformation slopes from deformation data requires further advancement. This limitation not only poses challenges for subsequent studies but also restricts the potential for deeper exploration and utilization of deformation data. The LT-1 satellite, China’s largest L-band synthetic aperture radar satellite, offers a new perspective for monitoring. In this study, we extracted deformation slopes in Chongqing and its surrounding areas of China based on deformation data generated by LT-1. Twelve factors were selected to analyze their influence on slope deformation, including elevation, topographic position, slope, landcover, soil, lithology, relief, average rainfall intensity, and distances to rivers, roads, railways, and active faults. A total of 5863 deformation slopes were identified, covering an area of 140 km², mainly concentrated in the central part of the study area, with the highest area density reaching 0.22%. Among these factors, average rainfall intensity was found to have the greatest impact on deformation slope. These findings provide valuable information for geological disaster early warning and management in Chongqing and surrounding areas, while also demonstrating the practical value of the LT-1 satellite in deformation monitoring. Full article

As cities have expanded into floodplains, the need for their protection has become crucial, prompting the evolution of flood studies. Here, we describe the operational tools, methods and processes used in flood risk engineering studies in the 1970s, and we evaluate the technological progress up to the present day. To this aim, we reference relevant regulations and legislation and the recorded experiences of engineers who performed hydrological, surveying and hydraulic studies in the 1970s. These are compared with the operational framework of a contemporary flood risk assessment study conducted in the Pikrodafni basin in the Attica region. We conclude that, without the technologically advanced tools available today, achieving the level of detail and accuracy in flood mapping that is now possible would have been unfeasible, even with significant human resources. However, ongoing urban development and growth continue to encroach upon flood plains that have existed for centuries, contributing to increased flood risk. Full article

In this research, a numerical model for simulating dam break floods was developed utilizing ArcGIS 10.8, 3ds Max 2021, and Flow-3D v11.2 software, with the aim of accurately representing the dam break disaster at Tianchi Lake in Changbai Mountain. The study involved the construction of a Triangulated Irregular Network (TIN) terrain surface and the application of 3ds Max 2021 to enhance the precision of the three-dimensional terrain data, thereby optimizing the depiction of the region’s topography. The finite volume method, along with multi-block grid technology, was employed to model the dam break scenario at Tianchi Lake. To evaluate the severity of the dam break disaster, the research integrated land use classifications within the study area with the simulated flood depths resulting from the dam break, applying the natural breaks method for hazard level classification. The findings indicated that the computational fluid dynamics (CFD) numerical model developed in this study significantly enhanced both the efficiency and accuracy of the simulations. Furthermore, the disaster assessment methodology that incorporated land use types facilitated the generation of inundation maps and disaster zoning maps across two scenarios, thereby effectively assessing the impacts of the disaster under varying conditions. Full article

Background: Plexiform neurofibromas (PNs) are histologically benign peripheral nerve sheath tumors associated with neurofibromatosis type 1 (NF1) and often lead to significant morbidity due to growth. Management includes watchful waiting, surgery for partial debulking, and, since recently, systemic treatment with MEK inhibitors. However, due to the scarcity of natural history studies, our understanding of the natural progression of PNs to guide clinicians in deciding in whom and when to intervene is scarce. This study aims to describe the characteristics of NF1 patients with PNs and compare those at high risk for PN progression or experiencing significant morbidity from PN (complex PN) with NF1 patients with PNs of lower complexity. Methods: In this retrospective cohort study using clinical data from hospital records of NF1 patients with PNs seen at the Sophia Children’s Hospital in the Netherlands between 2012 and 2023, we assessed determinants of clinical phenotypes and PN characteristics predictive of outcomes, including PN complexity and the timing of intervention for PN. We assessed the outcomes using logistic regression analysis and Cox regression. Results: Ninety patients with a median age at last evaluation of 15.7 years and a median follow-up duration of 9.8 years were included. Out of 90 individuals with a benign PN, 37 developed plexiform neurofibroma morbidity during follow-up. Older age was (corrected for pathogenic NF1 variant and PN location) significantly associated with plexiform neurofibroma morbidity. Cox regression revealed that craniofacial and trunk PNs were associated with a higher intervention hazard compared to limb PNs. Conclusion: Our pilot multivariate approach identified older age and the location of the PN to be mostly associated with a higher chance of plexiform neurofibroma morbidity and higher intervention hazard. This may contribute to decisions regarding in whom and when to initiate treatment in NF1 patients with PNs. Full article

The coast is the most dynamic part of the Earth’s surface due to its strategic position at the interface of the land and the sea. It is, therefore, exposed to hazards and specific risks because of the geography as well as the geological and environmental characteristics of different countries. The coastal environment is essentially dynamic and evolving in time and space, marked by waves, tides, and seasons; moreover, it is subjected to many marine and continental processes (forcing). This succession of events significantly influences the frequency and severity of coastal hazards. The present paper aims at describing and characterizing the hazards and vulnerabilities on the Cameroonian coast. Cameroon possesses 400 km of coastline, which is exposed to various hazards. It is important to determine the probabilities of these hazards, the associated effects, and the related vulnerabilities. In this study, in this stable intraplate setting, the methodology used was diverse and combined techniques for the study of the shore and methods for the treatment of climatic data. Also, historical data were collected during field observations and from the CRED website for all the natural hazards recorded in Cameroon. In addition, documents on climate change were consulted. Remotely sensed data, combined with GIS tools, helped to determine and assess the associated risks. A critical grid combining a severity and frequency analysis was used to better understand these hazards and the coastal vulnerabilities of Cameroon. The results show that Cameroon’s coastal margins are subject to natural processes that cause shoreline changes, including inundation, erosion, and accretion. This study identified seven primary hazard types (earthquakes, volcanism, landslides, floods, erosion, sea level rise, and black tides) affecting the Cameroonian coastline, with the erosion rate exceeding 1.15 m/year at Cape Cameroon. Coastal populations are continuously threatened by these natural or man-induced hazards, and they are periodically subjected to catastrophic disasters such as floods and landslides, as experienced in Cameroon. In addition, despite the existence of the National Contingency Plan devised by the Directorate of Civil Protection, National Risk, and Climate Change Observatories, the implementation of disaster risk reduction and mitigation strategies is suboptimal. Full article