| 1. |
|
|
| 2. |
|
|
| 3. |
- Klionsky, Daniel J., et al.
(author)
-
Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
-
In: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
-
Research review (peer-reviewed)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
|
|
| 4. |
- Dalton, A. S., et al.
(author)
-
An updated radiocarbon-based ice margin chronology for the last deglaciation of the North American Ice Sheet Complex
- 2020
-
In: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791. ; 234
-
Journal article (peer-reviewed)abstract
- The North American Ice Sheet Complex (NAISC; consisting of the Laurentide, Cordilleran and Innuitian ice sheets) was the largest ice mass to repeatedly grow and decay in the Northern Hemisphere during the Quaternary. Understanding its pattern of retreat following the Last Glacial Maximum is critical for studying many facets of the Late Quaternary, including ice sheet behaviour, the evolution of Holocene landscapes, sea level, atmospheric circulation, and the peopling of the Americas. Currently, the most up-to-date and authoritative margin chronology for the entire ice sheet complex is featured in two publications (Geological Survey of Canada Open File 1574 [Dyke et al., 2003]; 'Quaternary Glaciations - Extent and Chronology, Part II' [Dyke, 2004]). These often-cited datasets track ice margin recession in 36 time slices spanning 18 ka to 1 ka (all ages in uncalibrated radiocarbon years) using a combination of geomorphology, stratigraphy and radiocarbon dating. However, by virtue of being over 15 years old, the ice margin chronology requires updating to reflect new work and important revisions. This paper updates the aforementioned 36 ice margin maps to reflect new data from regional studies. We also update the original radiocarbon dataset from the 2003/2004 papers with 1541 new ages to reflect work up to and including 2018. A major revision is made to the 18 ka ice margin, where Banks and Eglinton islands (once considered to be glacial refugia) are now shown to be fully glaciated. Our updated 18 ka ice sheet increased in areal extent from 17.81 to 18.37 million km(2), which is an increase of 3.1% in spatial coverage of the NAISC at that time. Elsewhere, we also summarize, region-by-region, significant changes to the deglaciation sequence. This paper integrates new information provided by regional experts and radiocarbon data into the deglaciation sequence while maintaining consistency with the original ice margin positions of Dyke et al. (2003) and Dyke (2004) where new information is lacking; this is a pragmatic solution to satisfy the needs of a Quaternary research community that requires up-to-date knowledge of the pattern of ice margin recession of what was once the world's largest ice mass. The 36 updated isochrones are available in PDF and shapefile format, together with a spreadsheet of the expanded radiocarbon dataset (n = 5195 ages) and estimates of uncertainty for each interval. (C) 2020 Elsevier Ltd. All rights reserved.
|
|
| 5. |
- Menounos, B., et al.
(author)
-
Cordilleran Ice Sheet mass loss preceded climate reversals near the Pleistocene Termination
- 2017
-
In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 358:6364, s. 781-784
-
Journal article (peer-reviewed)abstract
- The Cordilleran Ice Sheet (CIS) once covered an area comparable to that of Greenland. Previous geologic evidence and numerical models indicate that the ice sheet covered much of westernmost Canada as late as 12.5 thousand years ago (ka). New data indicate that substantial areas throughout westernmost Canada were ice free prior to 12.5 ka and some as early as 14.0 ka, with implications for climate dynamics and the timing of meltwater discharge to the Pacific and Arctic oceans. Early Bolling-Allerod warmth halved the mass of the CIS in as little as 500 years, causing 2.5 to 3.0 meters of sea-level rise. Dozens of cirque and valley glaciers, along with the southern margin of the CIS, advanced into recently deglaciated regions during the Bolling-Allerod and Younger Dryas.
|
|
| 6. |
- Timmins, Iain R., et al.
(author)
-
International pooled analysis of leisure-time physical activity and premenopausal breast cancer in women from 19 cohorts
- 2024
-
In: Journal of Clinical Oncology. - : American Society of Clinical Oncology. - 0732-183X .- 1527-7755. ; 42:8, s. 927-939
-
Journal article (peer-reviewed)abstract
- PURPOSE: There is strong evidence that leisure-time physical activity is protective against postmenopausal breast cancer risk but the association with premenopausal breast cancer is less clear. The purpose of this study was to examine the association of physical activity with the risk of developing premenopausal breast cancer.METHODS: We pooled individual-level data on self-reported leisure-time physical activity across 19 cohort studies comprising 547,601 premenopausal women, with 10,231 incident cases of breast cancer. Multivariable Cox regression was used to estimate hazard ratios (HRs) and 95% CIs for associations of leisure-time physical activity with breast cancer incidence. HRs for high versus low levels of activity were based on a comparison of risk at the 90th versus 10th percentiles of activity. We assessed the linearity of the relationship and examined subtype-specific associations and effect modification across strata of breast cancer risk factors, including adiposity.RESULTS: Over a median 11.5 years of follow-up (IQR, 8.0-16.1 years), high versus low levels of leisure-time physical activity were associated with a 6% (HR, 0.94 [95% CI, 0.89 to 0.99]) and a 10% (HR, 0.90 [95% CI, 0.85 to 0.95]) reduction in breast cancer risk, before and after adjustment for BMI, respectively. Tests of nonlinearity suggested an approximately linear relationship (Pnonlinearity = .94). The inverse association was particularly strong for human epidermal growth factor receptor 2-enriched breast cancer (HR, 0.57 [95% CI, 0.39 to 0.84]; Phet = .07). Associations did not vary significantly across strata of breast cancer risk factors, including subgroups of adiposity.CONCLUSION: This large, pooled analysis of cohort studies adds to evidence that engagement in higher levels of leisure-time physical activity may lead to reduced premenopausal breast cancer risk.
|
|
| 7. |
- Selck, H., et al.
(author)
-
Assessing and managing multiple risks in a changing worldThe Roskilde recommendations
- 2017
-
In: Environmental Toxicology and Chemistry. - Hoboken, NJ : Wiley. - 0730-7268 .- 1552-8618. ; 36:1, s. 7-16
-
Journal article (peer-reviewed)abstract
- Roskilde University (Denmark) hosted a November 2015 workshop, Environmental RiskAssessing and Managing Multiple Risks in a Changing World. This Focus article presents the consensus recommendations of 30 attendees from 9 countries regarding implementation of a common currency (ecosystem services) for holistic environmental risk assessment and management; improvements to risk assessment and management in a complex, human-modified, and changing world; appropriate development of protection goals in a 2-stage process; dealing with societal issues; risk-management information needs; conducting risk assessment of risk management; and development of adaptive and flexible regulatory systems. The authors encourage both cross-disciplinary and interdisciplinary approaches to address their 10 recommendations: 1) adopt ecosystem services as a common currency for risk assessment and management; 2) consider cumulative stressors (chemical and nonchemical) and determine which dominate to best manage and restore ecosystem services; 3) fully integrate risk managers and communities of interest into the risk-assessment process; 4) fully integrate risk assessors and communities of interest into the risk-management process; 5) consider socioeconomics and increased transparency in both risk assessment and risk management; 6) recognize the ethical rights of humans and ecosystems to an adequate level of protection; 7) determine relevant reference conditions and the proper ecological context for assessments in human-modified systems; 8) assess risks and benefits to humans and the ecosystem and consider unintended consequences of management actions; 9) avoid excessive conservatism or possible underprotection resulting from sole reliance on binary, numerical benchmarks; and 10) develop adaptive risk-management and regulatory goals based on ranges of uncertainty. Environ Toxicol Chem 2017;36:7-16. (c) 2016 SETAC
|
|
| 8. |
- Von Holle, Ann, et al.
(author)
-
BMI and breast cancer risk around age at menopause
- 2024
-
In: Cancer Epidemiology. - : Elsevier. - 1877-7821 .- 1877-783X. ; 89
-
Journal article (peer-reviewed)abstract
- Background: A high body mass index (BMI, kg/m2) is associated with decreased risk of breast cancer before menopause, but increased risk after menopause. Exactly when this reversal occurs in relation to menopause is unclear. Locating that change point could provide insight into the role of adiposity in breast cancer etiology.Methods: We examined the association between BMI and breast cancer risk in the Premenopausal Breast Cancer Collaborative Group, from age 45 up to breast cancer diagnosis, loss to follow-up, death, or age 55, whichever came first. Analyses included 609,880 women in 16 prospective studies, including 9956 who developed breast cancer before age 55. We fitted three BMI hazard ratio (HR) models over age-time: constant, linear, or nonlinear (via splines), applying piecewise exponential additive mixed models, with age as the primary time scale. We divided person-time into four strata: premenopause; postmenopause due to natural menopause; postmenopause because of interventional loss of ovarian function (bilateral oophorectomy (BO) or chemotherapy); postmenopause due to hysterectomy without BO. Sensitivity analyses included stratifying by BMI in young adulthood, or excluding women using menopausal hormone therapy.Results: The constant BMI HR model provided the best fit for all four menopausal status groups. Under this model, the estimated association between a five-unit increment in BMI and breast cancer risk was HR=0.87 (95% CI: 0.85, 0.89) before menopause, HR=1.00 (95% CI: 0.96, 1.04) after natural menopause, HR=0.99 (95% CI: 0.93, 1.05) after interventional loss of ovarian function, and HR=0.88 (95% CI: 0.76, 1.02) after hysterectomy without BO.Conclusion: The BMI breast cancer HRs remained less than or near one during the 45–55 year age range indicating that the transition to a positive association between BMI and risk occurs after age 55.
|
|
| 9. |
- Dalton, April S., et al.
(author)
-
Deglaciation of the north American ice sheet complex in calendar years based on a comprehensive database of chronological data: NADI-1
- 2023
-
In: QUATERNARY SCIENCE REVIEWS. - 0277-3791 .- 1873-457X. ; 321
-
Journal article (peer-reviewed)abstract
- The most recent deglaciation of the North American Ice Sheet Complex (NAISC: comprising the Innuitian, Cordilleran, and Laurentide ice sheets) offers a broad perspective from which to analyze the timing and rate of ice retreat, deglacial sea-level rise, and abrupt climate change events. Previous efforts to portray the retreat of the NAISC have been focused largely on minimum-limiting radiocarbon ages and ice margin location(s) tied to deglacial landforms that were not, for the most part, chronologically constrained. Here, we present the first version of North American Deglaciation Isochrones (NADI-1) spanning 25 to 1 ka in calendar years before present. Key new features of this work are (i) the incorporation of cosmogenic nuclide data, which offer a direct constraint on the timing of ice recession; (ii) presentation of all data and time-steps in calendar years; (iii) optimal, minimum, and maximum ice extents for each time-step that are designed to capture uncertainties in the ice margin position, and; (iv) extensive documentation and justification for the placement of each ice margin. Our data compilation includes 2229 measurements of Be-10, 459 measurements of Al-26 and 35 measurements of Cl-36 from a variety of settings, including boulders, bedrock surfaces, cobbles, pebbles, and sediments. We also updated a previous radiocarbon dataset (n = 4947), assembled luminescence ages (n = 397) and gathered uranium-series data (n = 2). After scrutiny of the geochronological dataset, we consider >90% of data to be reliable or likely reliable. Key findings include (i) a highly asynchronous maximum glacial extent in North America, occurring as early as 27 ka to as late as 17 ka, within and between ice sheets. In most marine realms, extension of the ice margin to the continental shelf break at 25 ka is somewhat speculative because it is based on undated and spatially scattered ice stream and geomorphic evidence; (ii) detachment of the Laurentide and Cordilleran ice sheets took place gradually via southerly and northerly 'unzipping' of the ice masses, starting at 17.5 ka and ending around 14 ka; (iii) the final deglaciation of Hudson Bay began at 8.5 ka, with the collapse completed by 8 ka. The maximum extent of ice during the last glaciation occurred at 22 ka and covered 15,470,000 km(2). All North American ice sheets merged at 22 ka for the first time in the Quaternary. The highly asynchronous Last Glacial Maximum in North America means that our isochrones (starting at 25 ka) capture ice advance across some areas, which is based on limited evidence and is therefore somewhat speculative. In the Supplementary Data, the complete NADI-1 chronology is available in PDF, GIF and shapefile format, together with additional visualizations and spreadsheets of geochronological data. The NADI-1 shapefiles are also available at https://doi.org/10.5281/zenodo.8161764.
|
|
| 10. |
- Dalton, April S., et al.
(author)
-
The marine δ18O record overestimates continental ice volume during Marine Isotope Stage 3
- 2022
-
In: Global and Planetary Change. - Amsterdam : Elsevier. - 0921-8181 .- 1872-6364. ; 212, s. 103814-103814
-
Journal article (peer-reviewed)abstract
- There is disagreement in the Quaternary research community in how much of the marine δ18O signal is driven by change in ice volume. Here, we examine this topic by bringing together empirical and modelling work for Marine Isotope Stage 3 (MIS 3; 57 ka to 29 ka), a time when the marine δ18O record indicates moderate continental glaciation and a global mean sea level between −60 m and −90 m. We compile and interpret geological data dating to MIS 3 to constrain the extent of major Northern Hemisphere ice sheets (Eurasian, Laurentide, Cordilleran). Many key data, especially published in the past ~15 years, argue for an ice-free core of the formerly glaciated regions that is inconsistent with inferences from the marine δ18O record. We compile results from prior studies of glacial isostatic adjustment to show the volume of ice inferred from the marine δ18O record is unable to fit within the plausible footprint of Northern Hemisphere ice sheets during MIS 3. Instead, a global mean sea level between −30 m and − 50 m is inferred from geological constraints and glacial isostatic modelling. Furthermore, limited North American ice volumes during MIS 3 are consistent with most sea-level bounds through that interval. We can find no concrete evidence of large-scale glaciation during MIS 3 that could account for the missing ~30 m of sea-level equivalent during that time, which suggests that changes in the marine δ18O record are driven by other variables, including water temperature. This work urges caution regarding the reliance of the marine δ18O record as a de facto indicator of continental ice when few geological constraints are available, which underpins many Quaternary studies.
|
|
| 11. |
- Huss, M., et al.
(author)
-
Toward mountains without permanent snow and ice
- 2017
-
In: Earth's Future. - 2328-4277. ; 5:5, s. 418-435
-
Research review (peer-reviewed)abstract
- The cryosphere in mountain regions is rapidly declining, a trend that is expected to accelerate over the next several decades due to anthropogenic climate change. A cascade of effects will result, extending from mountains to lowlands with associated impacts on human livelihood, economy, and ecosystems. With rising air temperatures and increased radiative forcing, glaciers will become smaller and, in some cases, disappear, the area of frozen ground will diminish, the ratio of snow to rainfall will decrease, and the timing and magnitude of both maximum and minimum streamflow will change. These changes will affect erosion rates, sediment, and nutrient flux, and the biogeochemistry of rivers and proglacial lakes, all of which influence water quality, aquatic habitat, and biotic communities. Changes in the length of the growing season will allow low-elevation plants and animals to expand their ranges upward. Slope failures due to thawing alpine permafrost, and outburst floods from glacier-and moraine-dammed lakes will threaten downstream populations.Societies even well beyond the mountains depend on meltwater from glaciers and snow for drinking water supplies, irrigation, mining, hydropower, agriculture, and recreation. Here, we review and, where possible, quantify the impacts of anticipated climate change on the alpine cryosphere, hydrosphere, and biosphere, and consider the implications for adaptation to a future of mountains without permanent snow and ice.
|
|
| 12. |
- Clague, JJ, et al.
(author)
-
Late Holocene environmental change at treeline in the Northern Coast Mountains, British Columbia, Canada
- 2004
-
In: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791. ; 23:23-24, s. 2413-2431
-
Journal article (peer-reviewed)abstract
- An integrated stratigraphic, paleoecological, and geochronological study of lake and fen sediments just beyond the terminus of Berendon Glacier provides insights into late Holocene climate, vegetation, and glacier change in the northern Coast Mountains of British Columbia. Cores collected from two small lakes in the foreland of Berendon Glacier and pits dug in a nearby fen record Little lee Age and older glacier advances. The first Little Ice Age advance in this area began more than 500 years ago and peaked in the early 17th century. An earlier Neoglacial advance began about 2800-3000 cal yr ago and may have lasted for hundreds of years. There is also evidence for an intervening advance of even smaller magnitude around 1200-1300 cal yr ago. The advances are broadly synchronous with those in other parts of western North America, indicating that they were caused by regional, possibly global, changes in climate. Plant communities within the study area did not change dramatically during the late Holocene. The ranges of some plants, however, likely retracted or extended near treeline in response to changes in mean temperatures of perhaps 1-2degreesC, as A well as changes in summer snow cover. The greatest changes in vegetation occurred within and just beyond the forefields of Berendon, Frank Mackie, and other nearby glaciers. The largest climate shifts of the last 3000 years took place during the late Little Ice Age and the last century. Climate warmed about 1-2degreesC during the 20th century, accompanied by a rise in treeline, an increase in coniferous tree cover in the subalpine zone, and an increase in the temperature and biological productivity of ponds. These trends are likely to continue if climate, as expected, continues to warm. (C) 2004 Elsevier Ltd. All rights reserved.
|
|
| 13. |
- Margold, Martin, et al.
(author)
-
Retreat pattern of the Cordilleran Ice Sheet in central British Columbia at the end of the last glaciation reconstructed from glacial meltwater landforms
- 2013
-
In: Boreas. - : Wiley. - 0300-9483 .- 1502-3885. ; 42:4, s. 830-847
-
Journal article (peer-reviewed)abstract
- The Cordilleran Ice Sheet (CIS) covered much of the mountainous northwestern part of North America at least several times during the Pleistocene. The pattern and timing of its growth and decay are, however, poorly understood. Here, we present a reconstruction of the pattern of ice-sheet retreat in central British Columbia at the end of the last glaciation based on a palaeoglaciological interpretation of ice-marginal meltwater channels, eskers and deltas mapped from satellite imagery and digital elevation models. A consistent spatial pattern of high-elevation (1600-2400m a.s.l.), ice-marginal meltwater channels is evident across central British Columbia. These landforms indicate the presence of ice domes over the Skeena Mountains and the central Coast Mountains early during deglaciation. Ice sourced in the Coast Mountains remained dominant over the southern and east-central parts of the Interior Plateau during deglaciation. Our reconstruction shows a successive westward retreat of the ice margin from the western foot of the Rocky Mountains, accompanied by the formation and rapid evolution of a glacial lake in the upper Fraser River basin. The final stage of deglaciation is characterized by the frontal retreat of ice lobes through the valleys of the Skeena and Omineca Mountains and by the formation of large esker systems in the most prominent topographic lows of the Interior Plateau. We conclude that the CIS underwent a large-scale reconfiguration early during deglaciation and was subsequently diminished by thinning and complex frontal retreat towards the Coast Mountains.
|
|
| 14. |
- Margold, Martin, et al.
(author)
-
Timing of terminal Pleistocene deglaciation at high elevations in southern and central British Columbia constrained by Be-10 exposure dating
- 2014
-
In: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 99, s. 193-202
-
Journal article (peer-reviewed)abstract
- The Cordilleran Ice Sheet (CIS) covered most of British Columbia and southern Yukon Territory at the local Last Glacial Maximum (ILGM) during Marine Oxygen Isotope Stage 2. However, its subsequent demise is not well understood, particularly at high elevations east of its ocean-terminating margin. We present Be-10 exposure ages from two high-elevation sites in southern and central British Columbia that help constrain the time of initial deglaciation at these sites. We sampled granodiorite erratics at elevations of 2126-2230 m a.s.l. in the Marble Range and 1608-1785 m a.s.l. in the Telkwa Range at the western margin of the Interior Plateau. The erratics at both sites are near ice-marginal meltwater channels that delineate the local ice surface slope and thus the configuration of the ice sheet during deglaciation. The locations of the erratics and their relations to meltwater channels ensure that the resulting Be-10 ages date CIS deglaciation and not the retreat of local montane glaciers. Our sample sites emerged above the surface of the CIS as its divide migrated westward from the Interior Plateau to the axis of the Coast Mountains. Two of the four samples from the summit area of the Marble Range yielded apparent exposure ages of 14.0 +/- 0.7 and 15.2 +/- 0.8 ka. These ages are 1.8-3.0 ka younger than the well-established ILGM age of ca 17 ka for the Puget lobe of the CIS in Washington State; they are 1.7 ka younger than the ILGM age for the Puget lobe if a snow-shielding correction to their uncertainty-weighted mean age is applied. The other two samples yielded much older apparent exposure ages (20.6 +/- 1.4 and 33.0 +/- 1.5 ka), indicating the presence of inherited isotopes. Four samples collected from the summit area of the Telkwa Range in the Hazelton Mountains yielded well clustered apparent exposure ages of 10.1 +/- 0.6, 10.2 +/- 0.7, 10.4 +/- 0.5, and 11.5 +/- 1.1 ka. Significant present-day snow cover introduces a large uncertainty in the apparent exposure ages from this site. A snow-shielding correction based on present-day snow cover data increases the uncertainty-weighted mean exposure age of the Telkwa Range erratics to 12.4 +/- 0.7 ka, consistent with deglacial C-14 ages from areas near sea level to the west. Our exposure ages show a thinning of the southern portion of the CIS shortly after the ILGM and persistence of a remnant mountain ice cap in the central Coast Mountains into the Younger Dryas Chronozone. Our data also show that the summit area of the Marble Range was ice-covered during the ILGM. The presence of an ice body of considerable dimension in north-central British Columbia until, or possibly even after, the Younger Dryas highlights the need for geomorphological and geochronological studies of the ice dispersal centre over the Skeena Mountains in northwest British Columbia and the need for better understanding of the response of the CIS to Lateglacial climate fluctuations.
|
|
| 15. |
- Nhu, Viet-Ha, et al.
(author)
-
Landslide Susceptibility Mapping Using Machine Learning Algorithms and Remote Sensing Data in a Tropical Environment
- 2020
-
In: International Journal of Environmental Research and Public Health. - Switzerland : MDPI. - 1661-7827 .- 1660-4601. ; 17:14
-
Journal article (peer-reviewed)abstract
- We used AdaBoost (AB), alternating decision tree (ADTree), and their combination as an ensemble model (AB-ADTree) to spatially predict landslides in the Cameron Highlands, Malaysia. The models were trained with a database of 152 landslides compiled using Synthetic Aperture Radar Interferometry, Google Earth images, and field surveys, and 17 conditioning factors (slope, aspect, elevation, distance to road, distance to river, proximity to fault, road density, river density, normalized difference vegetation index, rainfall, land cover, lithology, soil types, curvature, profile curvature, stream power index, and topographic wetness index). We carried out the validation process using the area under the receiver operating characteristic curve (AUC) and several parametric and non-parametric performance metrics, including positive predictive value, negative predictive value, sensitivity, specificity, accuracy, root mean square error, and the Friedman and Wilcoxon sign rank tests. The AB model (AUC = 0.96) performed better than the ensemble AB-ADTree model (AUC = 0.94) and successfully outperformed the ADTree model (AUC = 0.59) in predicting landslide susceptibility. Our findings provide insights into the development of more efficient and accurate landslide predictive models that can be used by decision makers and land-use managers to mitigate landslide hazards.
|
|
| 16. |
- Nhu, Viet-Ha, et al.
(author)
-
Shallow Landslide Susceptibility Mapping : A Comparison between Logistic Model Tree, Logistic Regression, Naïve Bayes Tree, Artificial Neural Network, and Support Vector Machine Algorithms
- 2020
-
In: International Journal of Environmental Research and Public Health. - Switzerland : MDPI. - 1661-7827 .- 1660-4601. ; 17:8, s. 1-30
-
Journal article (peer-reviewed)abstract
- Shallow landslides damage buildings and other infrastructure, disrupt agriculture practices, and can cause social upheaval and loss of life. As a result, many scientists study the phenomenon, and some of them have focused on producing landslide susceptibility maps that can be used by land-use managers to reduce injury and damage. This paper contributes to this effort by comparing the power and effectiveness of five machine learning, benchmark algorithms—Logistic Model Tree, Logistic Regression, Naïve Bayes Tree, Artificial Neural Network, and Support Vector Machine—in creating a reliable shallow landslide susceptibility map for Bijar City in Kurdistan province, Iran. Twenty conditioning factors were applied to 111 shallow landslides and tested using the One-R attribute evaluation (ORAE) technique for modeling and validation processes. The performance of the models was assessed by statistical-based indexes including sensitivity, specificity, accuracy, mean absolute error (MAE), root mean square error (RMSE), and area under the receiver operatic characteristic curve (AUC). Results indicate that all the five machine learning models performed well for shallow landslide susceptibility assessment, but the Logistic Model Tree model (AUC = 0.932) had the highest goodness-of-fit and prediction accuracy, followed by the Logistic Regression (AUC = 0.932), Naïve Bayes Tree (AUC = 0.864), ANN (AUC = 0.860), and Support Vector Machine (AUC = 0.834) models. Therefore, we recommend the use of the Logistic Model Tree model in shallow landslide mapping programs in semi-arid regions to help decision makers, planners, land-use managers, and government agencies mitigate the hazard and risk.
|
|
| 17. |
- Salvati, Aryan, et al.
(author)
-
Flood susceptibility mapping using support vector regression and hyper-parameter optimization
- 2023
-
In: Journal of Flood Risk Management. - : John Wiley and Sons Inc. - 1753-318X. ; 16:4
-
Journal article (peer-reviewed)abstract
- Floods are both complex and destructive, and in most parts of the world cause injury, death, loss of agricultural land, and social disruption. Flood susceptibility (FS) maps are used by land-use managers and land owners to identify areas that are at risk from flooding and to plan accordingly. This study uses machine learning ensembles to produce objective and reliable FS maps for the Haraz watershed in northern Iran. Specifically, we test the ability of the support vector regression (SVR), together with linear kernel (LK), base classifier (BC), and hyper-parameter optimization (HPO), to identify flood-prone areas in this watershed. We prepared a map of 201 past floods to predict future floods. Of the 201 flood events, 151 (75%) were used for modeling and 50 (25%) were used for validation. Based on the relevant literature and our field survey of the study area, 10 effective factors were selected and prepared for flood zoning. The results show that three of the 10 factors are most important for predicting flood-sensitive areas, specifically and in order of importance, slope, distance to the river and river. Additionally, the SVR-HPO model, with area under the curve values of 0.986 and 0.951 for the training and testing phases, outperformed the other two tested models.
|
|
| 18. |
- Shahabi, Himan, et al.
(author)
-
Flood Detection and Susceptibility Mapping Using Sentinel-1 Remote Sensing Data and a Machine Learning Approach : Hybrid Intelligence of Bagging Ensemble Based on K-Nearest Neighbor Classifier
- 2020
-
In: Remote Sensing. - Switzerland : MDPI. - 2072-4292. ; 12:2, s. 1-30
-
Journal article (peer-reviewed)abstract
- Mapping flood-prone areas is a key activity in flood disaster management. In this paper, we propose a new flood susceptibility mapping technique. We employ new ensemble models based on bagging as a meta-classifier and K-Nearest Neighbor (KNN) coarse, cosine, cubic, and weighted base classifiers to spatially forecast flooding in the Haraz watershed in northern Iran. We identified flood-prone areas using data from Sentinel-1 sensor. We then selected 10 conditioning factors to spatially predict floods and assess their predictive power using the Relief Attribute Evaluation (RFAE) method. Model validation was performed using two statistical error indices and the area under the curve (AUC). Our results show that the Bagging–Cubic–KNN ensemble model outperformed other ensemble models. It decreased the overfitting and variance problems in the training dataset and enhanced the prediction accuracy of the Cubic–KNN model (AUC=0.660). We therefore recommend that the Bagging–Cubic–KNN model be more widely applied for the sustainable management of flood-prone areas.
|
|
| 19. |
- Sharifipour, Behzad, et al.
(author)
-
Rangeland species potential mapping using machine learning algorithms
- 2023
-
In: Ecological Engineering. - : Elsevier. - 0925-8574 .- 1872-6992. ; 189
-
Journal article (peer-reviewed)abstract
- Documenting habitats of rangeland plant species is required to properly manage rangelands and to understand ecosystem processes. A reliable rangeland species potential map can help managers and policy makers design a sustainable grazing system on rangelands. The aim of this study is to map the plant species in the Qurveh City rangelands, Kurdistan Province, Iran, using state-of-the-art machine learning algorithms, including Support Vector Machine (SVM), Artificial Neural Network (ANN), Naïve Bayes (NB), Bayes Net (BN) and Classification and Regression Tree (CART). A total of 185 rangeland species were used in the study, together with 20 conditioning factors, to build and validate models. The One-R feature section technique and multicollinearity test were used, respectively, to determine the most important factors and correlations between them. Model validation was performed using sensitivity, specificity, accuracy, F1-measure, Matthews correlation coefficient (MCC), Kappa, root mean square error (RMSE), and area under the receiver operating characteristic curve (AUC). Results showed that topographic wetness index (TWI), slope angle, elevation, soil phosphorus and soil potassium were the five most important factors to increase the rangeland plants habitat suitability. The Naïve Bayes algorithm (AUC = 0.782) had the highest performance and prediction accuracy and best consistency across the species in the investigated rangeland, followed by the SVM (AUC = 0.763), ANN (AUC = 0.762), CART (AUC = 0.627), and BN (AUC = 0.617) models.
|
|
| 20. |
- Stroeven, Arjen, 1963-, et al.
(author)
-
Investigating the glacial history of the northern sector of the Cordilleran Ice Sheet with cosmogenic 10Be concentrations in quartz
- 2010
-
In: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 29:25-26, s. 3630-3643
-
Journal article (peer-reviewed)abstract
- Exposure durations of glacial landforms in widely separated areas of central Yukon Territory affected bythe northern sector of the Cordilleran Ice Sheet (CIS) and alpine glaciers have been determined usingcosmogenic 10Be in quartz. The aim of our research is to test previous reconstructions of glacial historyand to begin to address the paucity of chronological control for the lateral and vertical extent of thenorthern CIS. Chronological evidence for CIS expansion predating the Last Glacial Maximum comes fromminimum surface exposure durations of c 100 ka for two bedrock samples within the Reid glacial limit,indicating a possible marine Oxygen Isotope Stage (OIS) 6 age for this event, and from minimumexposure durations of about 40 ka for boulders on moraines constructed by alpine glaciers on a nunatakwithin the McConnell glacial limit (OIS 2), indicating a possible OIS 4 age. High elevation minimumsurface exposure durations within the McConnell limit indicate that some areas formerly mapped asnunataks were covered by cold-based ice prior to 30 ka. Montane glaciation in the Mackenzie Mountains,outside the McConnell glacial limit, was contemporaneous with nearby CIS advance at 17 ka, with CISretreat by 15 ka. Deglaciation of the Tintina Trench, a major ice discharge route, was completed by 12 ka.At this time ice in an adjacent discharge route to the south was still entering higher-elevation valleys inthe Pelly Mountains. A Lateglacial readvance may have peaked at ca 10 ka in the Ogilvie Mountains.Considerable variation in ages from individual landforms, and possible complex histories, requireadditional cosmogenic nuclide measurements to confirm interpretations.
|
|
| 21. |
- Stroeven, Arjen P., et al.
(author)
-
Investigating absolute chronologies of glacial advances in the NW sector of the Cordilleran Ice Sheet with terrestrial in situ cosmogenic nuclides
- 2014
-
In: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 92, s. 429-443
-
Journal article (peer-reviewed)abstract
- Geologic mapping in Yukon Territory, Canada, over the past 100 years has revealed a consistent pattern of diminishing Cordilleran Ice Sheet (CIS) extent during successively younger glaciations. Although this pattern is generally accepted, there is still much uncertainty about the number of glaciations, their ages, and the dynamics of the different lobes that constituted the digitate ice sheet margin, their subglacial thermal regimes, and ice thicknesses. We address uncertainties in the timing of glaciation using cosmogenic nuclide exposure dating at key localities that straddle several major lobes of the CIS in west-central Yukon Territory. Differences in exposure duration within what are thought to be the same map units are perhaps due to inheritance (older than expected), but more likely result from postglacial shielding (younger than expected) or surface erosion. Despite a significant spread in exposure durations on moraines and within map units, and tending to rely on longest exposure durations on moraines due to postglacial degradation and shielding, our results indicate that the McConnell glacial advance occurred during Marine Oxygen Isotope Stage (MIS) 2, judging from oldest minimum apparent exposure ages of 15.7 +/- 1.5 and 17.7 +/- 1.6 ka, a Gladstone glacial advance occurred before 51.8 +/- 4.7 ka (MIS 4) and Reid glacial advances before 79.8 +/- 7.3 and 82.8 +/- 7.5 ka (consistent with MIS 6). Traces of even older glacial advances predate 100 ka (107.5 +/- 9.9-154.3 +/- 14.2 ka).
|
|
