63 research outputs found
Global, regional and national burdens of non-melanoma skin cancer attributable to occupational exposure to solar ultraviolet radiation for 183 countries, 2000-2019: A systematic analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury.
A World Health Organization (WHO) and International Labour Organization (ILO) systematic review reported sufficient evidence for higher risk of non-melanoma skin cancer (NMSC) amongst people occupationally exposed to solar ultraviolet radiation (UVR). This article presents WHO/ILO Joint Estimates of global, regional, national and subnational occupational exposures to UVR for 195 countries/areas and the global, regional and national attributable burdens of NMSC for 183 countries, by sex and age group, for the years 2000, 2010 and 2019.
We calculated population-attributable fractions (PAFs) from estimates of the population occupationally exposed to UVR and the risk ratio for NMSC from the WHO/ILO systematic review. Occupational exposure to UVR was modelled via proxy of occupation with outdoor work, using 166 million observations from 763 cross-sectional surveys for 96 countries/areas. Attributable NMSC burden was estimated by applying the PAFs to WHO's estimates of the total NMSC burden. Measures of inequality were calculated.
Globally in 2019, 1.6 billion workers (95 % uncertainty range [UR] 1.6-1.6) were occupationally exposed to UVR, or 28.4 % (UR 27.9-28.8) of the working-age population. The PAFs were 29.0 % (UR 24.7-35.0) for NMSC deaths and 30.4 % (UR 29.0-31.7) for disability-adjusted life years (DALYs). Attributable NMSC burdens were 18,960 deaths (UR 18,180-19,740) and 0.5 million DALYs (UR 0.4-0.5). Men and older age groups carried larger burden. Over 2000-2019, attributable deaths and DALYs almost doubled.
WHO and the ILO estimate that occupational exposure to UVR is common and causes substantial, inequitable and growing attributable burden of NMSC. Governments must protect outdoor workers from hazardous exposure to UVR and attributable NMSC burden and inequalities
International pooled study on diet and bladder cancer: the bladder cancer, epidemiology and nutritional determinants (BLEND) study: Design and baseline characteristics
Background: In 2012, more than 400,000 urinary bladder cancer cases occurred worldwide, making it the 7th most common type of cancer. Although many previous studies focused on the relationship between diet and bladder cancer, the evidence related to specific food items or nutrients that could be involved in the development of bladder cancer remains inconclusive. Dietary components can either be, or be activated into, potential carcinogens through metabolism, or act to prevent carcinogen damage. Methods/design: The BLadder cancer, Epidemiology and Nutritional Determinants (BLEND) study was set up with the purpose of collecting individual patient data from observational studies on diet and bladder cancer. In total, data from 11,261 bladder cancer cases and 675,532 non-cases from 18 case-control and 6 cohort studies from all over the world were included with the aim to investigate the association between individual food items, nutrients and dietary patterns and risk of developing bladder cancer. Discussion: The substantial number of cases included in this study will enable us to provide evidence with large statistical power, for dietary recommendations on the prevention of bladder cancer
The global burden of cancer attributable to risk factors, 2010–19: a systematic analysis for the Global Burden of Disease Study 2019
BACKGROUND: Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. METHODS: The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk–outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. FINDINGS: Globally, in 2019, the risk factors included in this analysis accounted for 4·45 million (95% uncertainty interval 4·01–4·94) deaths and 105 million (95·0–116) DALYs for both sexes combined, representing 44·4% (41·3–48·4) of all cancer deaths and 42·0% (39·1–45·6) of all DALYs. There were 2·88 million (2·60–3·18) risk-attributable cancer deaths in males (50·6% [47·8–54·1] of all male cancer deaths) and 1·58 million (1·36–1·84) risk-attributable cancer deaths in females (36·3% [32·5–41·3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20·4% (12·6–28·4) and DALYs by 16·8% (8·8–25·0), with the greatest percentage increase in metabolic risks (34·7% [27·9–42·8] and 33·3% [25·8–42·0]). INTERPRETATION: The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden
Geomechanical characterisation of massive rock for deep TBM tunnelling
A combined geological and rock mechanics approach to tunnel face behaviour prediction,
based on improved understanding of brittle fracture processes during TBM excavation, was developed to
complement empirical design and performance prediction for TBM tunnelling applications in novel
geological conditions. A major challenge of this research is combining geological and engineering languages,
methods, and objectives to construct a unified geomechanics characterisation system. The goal of this system
is to describe the spalling sensitivity of hard, massive, highly stressed crystalline rock, often deformed by
tectonic processes. Geological, lab strength testing and TBM machine data were used to quantify the impact
of interrelated geological factors, such as mineralogy, grain size, fabric and the heterogeneity of all these
factors at micro and macro scale, on spalling sensitivity and to combine these factors within a TBM advance
framework. This was achieved by incorporating aspects of geology, tectonics, mineralogy, materials strength
theory, fracture process theory and induced stresses
Constitutive Model for Numerical Modelling of Highly Stressed Heterogeneous Massive Rocks at Excavation Boundaries
A numerical modelling approach was developed to explicitly simulate geomechanical characteristics of intact rock: mineralogy, grain size and fabric. The approach involved creating a representative constitutive model for each of three common rock-forming minerals: mica, quartz and feldspar. The constitutive models developed are valid within the low confinement realm of excavation boundaries, where tensile fracture processes dominate. The mineral types were assigned to numerical elements, which were associated with each other through an algorithm created in a finite difference model, FLAC 2D (Itasca 2007a), to simulate real crystal geometries and orientations. The numerical models were used in a parametric investigation of the geomechanical characteristics and compared with published observations of the rock yielding process in laboratory testing. This approach has allowed the explicit grain-scale investigation of the impact of geomechanical characteristics on rock yielding at low confinement, leading to an improved mechanistic understanding of excavation-scale rock yielding processes at excavation
boundaries
Physical property relationships of the Rotokawa Andesite, a significant geothermal reservoir rock in the Taupo Volcanic Zone, New Zealand
Background
Geothermal systems are commonly hosted in highly altered and fractured rock. As a result, the relationships between physical properties such as strength and permeability can be complex. Understanding such properties can assist in the optimal utilization of geothermal reservoirs. To resolve this issue, detailed laboratory studies on core samples from active geothermal reservoirs are required. This study details the results of the physical property investigations on Rotokawa Andesite which hosts a significant geothermal reservoir.
Methods
We have characterized the microstructure (microfracture density), porosity, density, permeability, elastic wave velocities, and strength of core from the high-enthalpy Rotokawa Andesite geothermal reservoir under controlled laboratory conditions. We have built empirical relationships from our observations and also used a classical micromechanical model for brittle failure. Further, we compare our results to a Kozeny-Carman permeability model to better constrain the fluid flow behavior of the rocks.
Results
We show that the strength, porosity, elastic moduli, and permeability are greatly influenced by pre-existing fracture occurrence within the andesite. Increasing porosity (or microfracture density) correlates well to a decreasing uniaxial compressive strength, increasing permeability, and a decreasing compressional wave velocity.
Conclusions
Our results indicate that properties readily measurable by borehole geophysical logging (such as porosity and acoustic velocities) can be used to constrain more complex and pertinent properties such as strength and permeability. The relationships that we have provided can then be applied to further understand processes in the Rotokawa reservoir and other reservoirs worldwide
The development and application of the alteration strength index equation
We have developed an Alteration Strength Index (ASI) equation to address the effect of hydrothermal alteration on mechanical rock properties. This equation can be used to estimate a range of rock strengths, comparable to uniaxial compressive strength (UCS), based on rapid analysis of mineralogy and microstructure. We used rock samples from three geothermal fields in the Taupo Volcanic Zone (TVZ) to represent a range of alteration types. These are sedimentary, intrusive and extrusive rocks, typical of geothermal systems, from shallow and deep boreholes (72 measured Depth (mD) to 3280 mD). The parameters used in ASI were selected based on literature relating these aspects of mineralogy and microstructure to rock strength. The parameters in ASI define the geological characteristics of the rock, such as proportions of primary and secondary mineralogy, individual mineral hardness, porosity and fracture number. We calibrated the ASI against measured UCS for our samples from the TVZ to produce a strong correlation (R2 of 0.86), and from this correlation we were able to derive an equation to convert ASI to UCS. Because the ASI–UCS relationship is based on an empirical fit, the UCS value that is obtained from conversion of the ASI includes an error of 7 MPa for the 50th percentile and 25 MPa for the 90th percentile with a mean error of 11 MPa. A sensitivity analysis showed that the mineralogy parameter is the dominant characteristic in this equation, and the ASI equation using only mineralogy can be used to provide an estimated UCS range, although the error (or uncertainty) becomes greater. This provides the ability to estimate strength even when either fracture or porosity information are not available, for example in the case of logging drill cuttings. This research has also allowed us to provide ranges of rock strengths based solely on the alteration zones, mineralogy, and depth of lithologies found in a typical geothermal field that can be used to update conceptual models of geothermal fields
Deformation, Strength, and Failure Mode of Deep Geothermal Reservoir Rocks
Rocks sourced from active geothermal systems can
have unique responses to deformation, due to unique
alteration mineralogy and complex microstructure.
The current state of understanding of mechanical
behaviour of rocks under varying stress conditions is
well established on suites of rocks with simple
mineralogy and microstructure. Brittle failure can
increase porosity and permeability and generate
seismicity, whereas inelastic deformation in the
ductile regime will decrease porosity and will likely
decrease permeability, and generate no or distinct low
frequency seismicity. Many studies have focused on
the behaviour of siliclastic and carbonate rocks to
establish the transition form brittle to ductile
behaviour. The geothermal systems in New Zealand,
and many other areas, are hosted in mainly volcanic
rocks, limiting the applicability of current data and
knowledge to these systems.
We present results from laboratory triaxial
deformation and strength testing of drill core sampled
from a deep geothermal reservoir. We have used our
findings to construct failure criteria based on our
investigations and compared them to the in-situ and
induced stress conditions that may lead to
macroscopically brittle or ductile deformation of the
host rock. Our results show that under the current
stress conditions at the Rotokawa geothermal field the
host rock behaves in a brittle, rather than compactive,
fashion. Under these in-situ stress conditions brittle
fracture generation dominates over cataclastic pore
collapse, resulting in a rock mass with suitable macroscale
permeability for fluid extraction. Our results also
show that the rock strength is typically too high for the
induced stresses during drilling to initiate borehole
breakout. This is supported by borehole observations
revealing very little borehole damage in the host rock
Engineering Geology Education for the 21st Century
A sound background in geology is necessary if geomechanics is to address the changing face of the
Earth as shown by recent geohazard events, by continued urban, infrastructure and resource
development, and by climate change both in New Zealand and internationally. Engineering geologists
provide this background in nearly every engineering consultancy, resource extraction and government
institution in Australasia.
We have used recent developments in post-secondary geo-education to create a learning experience
that meets the demands of the modern professional engineering geologist. We are developing a
revised programme of study that makes use of online and block learning, accommodating a societal
need for distance learning. Online interaction with lecturers and fellow students will be used for
delivery of subject fundamentals, while application of the concepts to practical examples will be
undertaken during short, intensive blocks. This structure will require students to both learn and
prepare independently, and increase the amount of experiential learning through project work and
involvement with industry.
We present four teaching and assessment techniques that are well suited to delivery through online
and block formats, while ensuring that students gain the technical and professional knowledge and
skills expected of engineering geologists. Online lecture delivery through interactive podcasts allows
students to study the lecture material at a distance, but we stress that this must be coupled with face-to-face
time. We use field work, group work and problem solving to allow students to reach the higher
levels of learning technical material, such as synthesis and evaluation, while gaining professional
skills
Rock mass properties and edifice strength data from Pinnacle Ridge, Mt. Ruapehu, New Zealand
International audienceVolcanic edifices exhibit spatially variable physical and mechanical properties. Magmatic intrusions are common at shallow depths within the volcanic edifice and are a poorly-understood contributor to this spatial variability. Intrusion-related alteration has been found to weaken rock mass strength through the development of joints and fractures; however, there is a paucity of research investigating how intrusions affect rock mass strength specific to the geotechnical units that define the rock masses. In this study, we employ a range of field techniques—field permeametry, rock hardness assessment, rock mass classification, and discontinuity mapping—to characterise an exposed fossil geothermal system produced by a shallow intrusion at Pinnacle Ridge, Mt. Ruapehu (New Zealand). We find that intrusions detrimentally affect the rock mass characteristics of altered brecciated lava margins. The resulting change in rock mass strength may be offset by an increase in intact rock strength as a product of alteration mineral precipitation in microfractures. Consequently, the final strength of the rock mass of the altered brecciated lava margins has the potential to be lowest of any of the geotechnical units in the volcanic edifice. We also conclude that these discontinuities increase permeability of the host rock at distances from the intrusion roughly proportional to 1–2 times the thickness of the intrusion itself under near-surface conditions. The data and conclusions presented in this study help to bridge the gap between the lab- and the field-scale and have immediate relevance to engineering geology and geothermal applications worldwide, and to rock mass classification assessments in volcanic environments
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