Retrogressive thaw slumps and active layer detachment slides in the Brooks Range and foothills of northern Alaska: terrain and timing

Thesis (Ph.D.) University of Alaska Fairbanks, 2015Permafrost degradation is widespread throughout the circumpolar north, occurring by multiple modes and mechanisms on many types of landscapes. The pan-Arctic rate of permafrost degradation is reportedly increasing, and permafrost carbon and nitrogen release are likely to be major contributors to global atmospheric greenhouse gas concentrations in coming decades. Locally, liberation of previously frozen substrates, organic materials, and nutrients alters the ecology of receiving streams, causes ecological and hydrobiogeochemical impacts in lake ecosystems, and impacts vegetation through disturbance, nutrient release, and succession on altered surfaces. Understanding the diverse modes of permafrost landscape response to climate, within time and space, is critical to questions of future impacts and feedbacks to climate change. Active layer detachment sliding and retrogressive thaw slumping are important modes of upland permafrost degradation and disturbance throughout the low arctic, and have been linked with climate warming trends, ecosystem impacts, and permafrost carbon release. In the Brooks Range and foothills study region of northwest Alaska, active layer detachment slides and retrogressive thaw slumps are widespread and prominant modes of permafrost degradation. Their distribution has been partially correlated with landscape properties, especially upper permafrost characteristics. However, drivers of active layer detachment slide and retrogressive thaw slump distribution and initiation triggering mechanisms, are poorly understood in this region, and detailed spatial distribution of permafrost characteristics is particularly lacking for the entire area. To better understand retrogressive thaw slump initiation triggers, this research used archived ERS-1 synthetic aperture RADAR data (1997-2010) to determine the year of first detection for 21 active retrogressive thaw slumps in the Noatak Basin, and examined weather records from remote and regional weather stations (1992-2011), along with satellite image-derived seasonal snowpack distribution (2000-2012) for correlations among weather, snowpack duration, and the timing of retrogressive thaw slump initiation. Most slumps first appeared within a 13 month span beginning June of 2004. Early summer 2004 was distinct in the weather records for anomalously warm early thaw-season temperatures, intense rainfall events in May, and unusually early dissipation of the annual snowpack. Results suggest that, regionally, retrogressive thaw slump initiation may be clustered in time, in response to seasonal shifts or anomalous weather events, and that future landscape response to climate change may depend on the nature and timing of climate change as much as overall magnitude. SS_para>The project examined inter-related and co-varying terrain properties at specific sites to identify relationships among terrain properties and permafrost characteristics. Consistent relationships among vegetation, surficial geology and permafrost characteristics were found using multiple factor analysis ordination of empirical data from diverse field sites throughout the region. Ordination results suggest relevant relationships among these factors to support regional-scale spatial analysis of terrain and permafrost properties. Field sites were also found to form consistent groupings from hierarchical clustering of ordination results, suggesting that relationships among these factors remain relevant across diverse gradients of landscape conditions in the region. Several thousand observed feature locations of active layer detachment slides and retrogressive thaw slumps were then used to examine region-wide terrain suitability based on terrain properties including: surficial geology, topography, geomorphology, vegetation and hydrology. Structural equation modeling and integrated terrain unit analyses confirmed and identified the nature and relative strength of relationships among terrain factors explaining observed feature distribution. These results may partially correspond with permafrost ground ice conditions as well, which is further supported by our ordination results. Analysis results drove mapped estimates of terrain suitability for active layer detachment slides and retrogressive thaw slumps across the region, enabling better estimates of permafrost carbon vulnerable to release, and ecosystems potentially impacted by these modes of permafrost degradation. Up to 57% of the study region may contain 'suitable' terrain for one or both of these features. Results support a 'state factor' approach as a useful organizing framework for assessing and describing terrain suitability, and for examining drivers of permafrost characteristics

The influence of expertise on brain activation of the action observation network during anticipation of tennis and volleyball serves

In many daily activities, and especially in sport, it is necessary to predict the effects of others´ actions in order to initiate appropriate responses. Recently, researchers have suggested that the action–observation network (AON) including the cerebellum plays an essential role during such anticipation, particularly in sport expert performers. In the present study, we examined the influence of task-specific expertise on the AON by investigating differences between two expert groups trained in different sports while anticipating action effects. Altogether, 15 tennis and 16 volleyball experts anticipated the direction of observed tennis and volleyball serves while undergoing functional magnetic resonance imaging (fMRI). The expert group in each sport acted as novice controls in the other sport with which they had only little experience. When contrasting anticipation in both expertise conditions with the corresponding untrained sport, a stronger activation of AON areas (SPL, SMA), and particularly of cerebellar structures, was observed. Furthermore, the neural activation within the cerebellum and the SPL was linearly correlated with participant´s anticipation performance, irrespective of the specific expertise. For the SPL, this relationship also holds when an expert performs a domain-specific anticipation task. Notably, the stronger activation of the cerebellum as well as of the SMA and the SPL in the expertise conditions suggests that experts rely on their more fine-tuned perceptual-motor representations that have improved during years of training when anticipating the effects of others´ actions in their preferred sport. The association of activation within the SPL and the cerebellum with the task achievement suggests that these areas are the predominant brain sites involved in fast motor predictions. The SPL reflects the processing of domain-specific contextual information and the cerebellum the usage of a predictive internal model to solve the anticipation task

A raster version of the Circumpolar Arctic Vegetation Map (CAVM)

Land cover maps are the basic data layer required for understanding and modeling ecological patterns and processes. The Circumpolar Arctic Vegetation Map (CAVM), produced in 2003, has been widely used as a base map for studies in the arctic tundra biome. However, the relatively coarse resolution and vector format of the map were not compatible with many other data sets. We present a new version of the CAVM, building on the strengths of the original map, while providing a finer spatial resolution, raster format, and improved mapping. The Raster CAVM uses the legend, extent and projection of the original CAVM. The legend has 16 vegetation types, glacier, saline water, freshwater, and non-arctic land. The Raster CAVM divides the original rock-water-vegetation complex map unit that mapped the Canadian Shield into two map units, distinguishing between areas with lichen- and shrub-dominated vegetation. In contrast to the original hand-drawn CAVM, the new map is based on unsupervised classifications of seventeen geographic/floristic sub-sections of the Arctic, using AVHRR and MODIS data (reflectance and NDVI) and elevation data. The units resulting from the classification were modeled to the CAVM types using a wide variety of ancillary data. The map was reviewed by experts familiar with their particular region, including many of the original authors of the CAVM from Canada, Greenland (Denmark), Iceland, Norway (including Svalbard), Russia, and the U.S. The analysis presented here summarizes the area, geographical distribution, elevation, summer temperatures, and NDVI of the map units. The greater spatial resolution of the Raster CAVM allowed more detailed mapping of water-bodies and mountainous areas. It portrays coastal-inland gradients, and better reflects the heterogeneity of vegetation type distribution than the original CAVM. Accuracy assessment of random 1-km pixels interpreted from 6 Landsat scenes showed an average of 70% accuracy, up from 39% for the original CAVM. The distribution of shrub-dominated types changed the most, with more prostrate shrub tundra mapped in mountainous areas, and less low shrub tundra in lowland areas. This improved mapping is important for quantifying existing and potential changes to land cover, a key environmental indicator for modeling and monitoring ecosystems. The final product is publicly available at www.geobotany.uaf.edu and at Mendeley Data, DOI: 10.17632/c4xj5rv6kv.1

Diverse patients' attitudes towards Artificial Intelligence (AI) in diagnosis.

Artificial intelligence (AI) has the potential to improve diagnostic accuracy. Yet people are often reluctant to trust automated systems, and some patient populations may be particularly distrusting. We sought to determine how diverse patient populations feel about the use of AI diagnostic tools, and whether framing and informing the choice affects uptake. To construct and pretest our materials, we conducted structured interviews with a diverse set of actual patients. We then conducted a pre-registered (osf.io/9y26x), randomized, blinded survey experiment in factorial design. A survey firm provided n = 2675 responses, oversampling minoritized populations. Clinical vignettes were randomly manipulated in eight variables with two levels each: disease severity (leukemia versus sleep apnea), whether AI is proven more accurate than human specialists, whether the AI clinic is personalized to the patient through listening and/or tailoring, whether the AI clinic avoids racial and/or financial biases, whether the Primary Care Physician (PCP) promises to explain and incorporate the advice, and whether the PCP nudges the patient towards AI as the established, recommended, and easy choice. Our main outcome measure was selection of AI clinic or human physician specialist clinic (binary, "AI uptake"). We found that with weighting representative to the U.S. population, respondents were almost evenly split (52.9% chose human doctor and 47.1% chose AI clinic). In unweighted experimental contrasts of respondents who met pre-registered criteria for engagement, a PCP's explanation that AI has proven superior accuracy increased uptake (OR = 1.48, CI 1.24-1.77, p < .001), as did a PCP's nudge towards AI as the established choice (OR = 1.25, CI: 1.05-1.50, p = .013), as did reassurance that the AI clinic had trained counselors to listen to the patient's unique perspectives (OR = 1.27, CI: 1.07-1.52, p = .008). Disease severity (leukemia versus sleep apnea) and other manipulations did not affect AI uptake significantly. Compared to White respondents, Black respondents selected AI less often (OR = .73, CI: .55-.96, p = .023) and Native Americans selected it more often (OR: 1.37, CI: 1.01-1.87, p = .041). Older respondents were less likely to choose AI (OR: .99, CI: .987-.999, p = .03), as were those who identified as politically conservative (OR: .65, CI: .52-.81, p < .001) or viewed religion as important (OR: .64, CI: .52-.77, p < .001). For each unit increase in education, the odds are 1.10 greater for selecting an AI provider (OR: 1.10, CI: 1.03-1.18, p = .004). While many patients appear resistant to the use of AI, accuracy information, nudges and a listening patient experience may help increase acceptance. To ensure that the benefits of AI are secured in clinical practice, future research on best methods of physician incorporation and patient decision making is required

Diverse patients’ attitudes towards Artificial Intelligence (AI) in diagnosis

Artificial intelligence (AI) has the potential to improve diagnostic accuracy. Yet people are often reluctant to trust automated systems, and some patient populations may be particularly distrusting. We sought to determine how diverse patient populations feel about the use of AI diagnostic tools, and whether framing and informing the choice affects uptake. To construct and pretest our materials, we conducted structured interviews with a diverse set of actual patients. We then conducted a pre-registered (osf.io/9y26x), randomized, blinded survey experiment in factorial design. A survey firm provided n = 2675 responses, oversampling minoritized populations. Clinical vignettes were randomly manipulated in eight variables with two levels each: disease severity (leukemia versus sleep apnea), whether AI is proven more accurate than human specialists, whether the AI clinic is personalized to the patient through listening and/or tailoring, whether the AI clinic avoids racial and/or financial biases, whether the Primary Care Physician (PCP) promises to explain and incorporate the advice, and whether the PCP nudges the patient towards AI as the established, recommended, and easy choice. Our main outcome measure was selection of AI clinic or human physician specialist clinic (binary, “AI uptake”). We found that with weighting representative to the U.S. population, respondents were almost evenly split (52.9% chose human doctor and 47.1% chose AI clinic). In unweighted experimental contrasts of respondents who met pre-registered criteria for engagement, a PCP’s explanation that AI has proven superior accuracy increased uptake (OR = 1.48, CI 1.24–1.77, p \u3c .001), as did a PCP’s nudge towards AI as the established choice (OR = 1.25, CI: 1.05–1.50, p = .013), as did reassurance that the AI clinic had trained counselors to listen to the patient’s unique perspectives (OR = 1.27, CI: 1.07–1.52, p = .008). Disease severity (leukemia versus sleep apnea) and other manipulations did not affect AI uptake significantly. Compared to White respondents, Black respondents selected AI less often (OR = .73, CI: .55-.96, p = .023) and Native Americans selected it more often (OR: 1.37, CI: 1.01–1.87, p = .041). Older respondents were less likely to choose AI (OR: .99, CI: .987-.999, p = .03), as were those who identified as politically conservative (OR: .65, CI: .52-.81, p \u3c .001) or viewed religion as important (OR: .64, CI: .52-.77, p \u3c .001). For each unit increase in education, the odds are 1.10 greater for selecting an AI provider (OR: 1.10, CI: 1.03–1.18, p = .004). While many patients appear resistant to the use of AI, accuracy information, nudges and a listening patient experience may help increase acceptance. To ensure that the benefits of AI are secured in clinical practice, future research on best methods of physician incorporation and patient decision making is required

Cerebral atrophy is associated with development of chronic subdural haematoma

OBJECTIVE: To test that cerebral atrophy is associated with increased risk for development of chronic subdural haematoma (cSDH), this study performed volumetric analysis of computed tomography (CT) brain scans from patients who were diagnosed with cSDH on subsequent CT scans and their age-matched controls. METHODS: Volumetric analysis was performed on CT scans acquired a mean of 209 days prior to cSDH diagnosis in 19 patients. Cerebral atrophy present on these scans was then compared to 76 age-matched control patients randomly selected from cSDH-free subjects. RESULTS: There was a higher degree of atrophy in cSDH patients (n = 19, 14.3% ± 5.4%) than in age-matched control patients (n = 76, 11.9% ± 5.5%; p = 0.044). Logistical regression demonstrated that atrophy was found to be a significant predictor of cSDH at all ages (OR = 1.11, 95% CI = [1.01, 1.23], p = 0.05). For younger subjects ≤65 years of age (n = 50), atrophy was an even stronger predictor of cSDH (OR = 1.17, 95% CI = [1.02, 1.34], p = 0.026). CONCLUSIONS: Cerebral atrophy is associated with the development of cSDH and this association is greater in patients ≤65 years of age

\u3ci\u3eParamecium bursaria\u3c/i\u3e Chlorella Virus 1 Proteome Reveals Novel Architectural and Regulatory Features of a Giant Virus

The 331 kilobase pairs chlorovirus PBCV-1 genome was re-sequenced and annotated to correct errors in the original 15 year old sequence; forty codons was considered the minimum protein size of an open reading frame. PBCV-1 encodes 416 predicted protein encoding sequences and 11 tRNAs. A proteome analysis was also conducted on highly purified PBCV-1 virions using two mass-spectrometry based protocols. The mass spectrometry-derived data were compared to PBCV-1 and its host Chlorella variabilis NC64A predicted proteomes. Combined, these analyses revealed 148 unique virus-encoded proteins associated with the virion (about 35% of the coding capacity of the virus) and one host protein. Some of these proteins appear to be structural/architectural, whereas others have enzymatic, chromatin modification and signal transduction functions. Most (106) of these proteins have no known function or homologs in the existing gene databases except as orthologs with other chloroviruses, phycodnaviruses and nuclear-cytoplasmic large DNA viruses. The genes encoding these proteins are dispersed throughout the virus genome and most are transcribed late or early late in the infection cycle, which is consistent with virion morphogenesis

Money Value Art : State Funding, Free Markets, Big Pictures

The essays and artists’ projects in this collection explore the issue of arts funding in Canada, particularly in light of cuts in government funding. Twenty-two authors address a diverse range of topics in a variety of styles, from humorous personal anecdotes to sociological analysis. The editors intend to mark a moment of flux in Canadian culture, when global capitalism is the dominant model. Includes a timeline of arts funding in Canada from 1941 to 2001. Notes on contributors. Bibliography 2 p. Circa 200 bibl. ref