Permafrost Distribution Mapping And Temperature Modeling Along The Alaska Highway Corridor, Interior Alaska

Thesis (Ph.D.) University of Alaska Fairbanks, 2011An up-to-date permafrost distribution map is critical for making engineering decisions during the planning and design of any engineering project in Interior Alaska. I used a combination of empirical-statistical and remote sensing techniques to generate a high-resolution spatially continuous near-surface (< 1.6 m) permafrost map by exploiting the correlative relationships between permafrost and biophysical terrain parameters. A Binary Logistic Regression (BLR) model was used to establish the relationship between vegetation type, aspect-slope and permafrost presence. The logistic coefficients for each variable class obtained from the BLR model were supplied to respective variable classes mapped from remotely sensed data to estimate permafrost probability for every pixel. The BLR model predicts permafrost presence/absence at an accuracy of 88%. Near-surface permafrost occupies 37% of the total study area. A permafrost map based on the interpretation of airborne electromagnetic (EM) resistivity data shows 22.5 -- 43.5% of the total study area as underlain by permafrost. Permafrost distribution statistics from both the maps suggest near-surface permafrost distribution in the study area is sporadic (10 -- 50 % of the area underlain by permafrost). Changes in air temperature and/or winter snow depth are important factors responsible for permafrost aggradation or degradation. I evaluated the effects of past and recent (1941-2008) climate changes on permafrost and active-layer dynamics at selected locations using the Geophysical Institute Permafrost Laboratory model. Results revealed that active-layer thickness reached 0.58 and 1.0 m, and mean annual permafrost temperature increased by 1.6 and 1.7 �C during 1966-1994 at two sites in response to increased mean annual air temperature, mean summer air temperature and winter snow depth. The study found that active-layer thickness is not only a function of summer air temperature but also of mean annual air temperature and winter snow depth. Model simulation with a projected (2008-2098) climate scenario predicts 0.22 m loss of near-surface permafrost at one site and complete permafrost disappearance at another site by 2098. The contrasting permafrost behaviors at different sites under similar climate scenarios highlight the role of soil type and ground ice volume on permafrost dynamics; these factors determine permafrost resilience under a warming climate

Association of ABO blood group with severe falciparum malaria in adults: case control study and meta-analysis

<p>Abstract</p> <p>Background</p> <p>Erythrocyte-associated antigenic polymorphisms or their absence have perhaps evolved in the human population to protect against malarial infection. Studies in various populations consistently demonstrate that blood group 'O' confers resistance against severe falciparum infection. In India, Odisha state has one of the highest incidences of <it>Plasmodium falciparum </it>infection and contributes to the highest number of deaths by falciparum malaria. This study aims to evaluate the relationship between ABO blood group and severe malaria in an adult population at the tertiary care centre in Odisha.</p> <p>Methods</p> <p>A total of 353 <it>P. falciparum </it>infected subjects and 174 healthy controls were screened for ABO blood group. Falciparum-infected individuals were categorized as severe malaria and uncomplicated malaria. Severe malaria was further clinically phenotyped into cerebral malaria, non-cerebral severe malaria and multi-organ dysfunction. A meta-analysis was performed to assess the role of ABO blood group in severe malaria.</p> <p>Results</p> <p>Frequency of blood group 'B' was significantly higher in patients with severe malaria compared to the uncomplicated cases (P < 0.0001; OR = 4.09) and healthy controls (P < 0.0001; OR = 2.79). Irrespective of the level of clinical severity, blood group 'B' was significantly associated with cerebral malaria (P < 0.0001; OR = 5.95), multi-organ dysfunction (P < 0.0001; OR = 4.81) and non-cerebral severe malaria patients (P = 0.001; OR = 3.02) compared to the uncomplicated category. Prevalence of 'O' group in uncomplicated malaria (P < 0.0001; OR = 2.81) and healthy controls (P = 0.0003; OR = 2.16) was significantly high compared to severe malaria. Meta-analysis of previous studies, including the current one, highlighted the protective nature of blood group 'O' to severe malaria (P = 0.01). On the other hand, carriers of blood group 'A' (P = 0.04) and 'AB' (P = 0.04) were susceptible to malaria severity.</p> <p>Conclusions</p> <p>Results of the current study indicate that blood group 'O' is associated with reduced and 'B' blood group with increased risk of development of severe malaria in Odisha, India. Meta-analysis also supports the protective nature of blood group 'O' from severe falciparum infection.</p

Innate Lymphoid Cells in Mucosal Immunity

Innate lymphoid cells (ILCs) are innate counterparts of T cells that contribute to immune responses by secreting effector cytokines and regulating the functions of other innate and adaptive immune cells. ILCs carry out some unique functions but share some tasks with T cells. ILCs are present in lymphoid and non-lymphoid organs and are particularly abundant at the mucosal barriers, where they are exposed to allergens, commensal microbes, and pathogens. The impact of ILCs in mucosal immune responses has been extensively investigated in the gastrointestinal and respiratory tracts, as well as in the oral cavity. Here we review the state-of-the-art knowledge of ILC functions in infections, allergy and autoimmune disorders of the mucosal barriers

Isolated cutaneous leishmaniasis over face – A diagnostic dilemma

Cutaneous Leishmaniasis (CL) is a disease caused by an intracellular protozoa belong to the genus Leishmania, transmitted by the bite of a sandfly. It has diverse clinical presentation and may create a public health problem in endemic countries. CL is often confused with lepromatous leprosy, pimples and fungal dermatitis. This case is an isolated cutaneous variety in facial region which was mistaken and treated initially for fungal dermatitis and then for leprosy by local physicians. Smears examined from the skin lesion confirmed Leishmania amastigotes. The isolated localized CL may create confusion and its many differential diagnoses made delaying in the diagnosis

ANTIULCER ACTIVITY OF AMARANTHUS SPINOSUS LEAF EXTRACT AND ITS COMPARISION WITH FAMOTIDINE IN SHAY RATS

Anti-ulcer activities of petroleum ether, chloroform, Ethanolic extract of Amaranthus spinosus leaf were tested for anti-gastric ulcer activity in Shay rat model. Oral dose of 400mg/kg of ethanolic extract reduced the ulceration and with 800mg/kg body weight ethanolic extract there is the complete absence of ulceration. The anti-gastric activity of ethanolic extract of A.spinosus 800mg/kg body weight was found to be equal to the effect produced by 2mg/kg of Famotidine orally. The reduction in gastric activity was more with Famotidine and the reduction in peptic activity is more with ethanolic extract of A.spinosus. All extracts are safe up to 4000mg/kg. The result of petroleum ether, chloroform and aqueous extract in respect of anti-ulcer activity are less prominent. Keywords: Amaranthus spinosus, Shay rat model, Famotidine, Peptic activityÂ

Improved Boreal Forest Wildfire Fuel Type Mapping in Interior Alaska Using AVIRIS-NG Hyperspectral Data

In Alaska the current wildfire fuel map products were generated from low spatial (30 m) and spectral resolution (11 bands) Landsat 8 satellite imagery which resulted in map products that not only lack the granularity but also have insufficient accuracy to be effective in fire and fuel management at a local scale. In this study we used higher spatial and spectral resolution AVIRIS-NG hyperspectral data (acquired as part of the NASA ABoVE project campaign) to generate boreal forest vegetation and fire fuel maps. Based on our field plot data, random forest classified images derived from 304 AVIRIS-NG bands at Viereck IV level (Alaska Vegetation Classification) had an 80% accuracy compared to the 33% accuracy of the LANDFIRE’s Existing Vegetation Type (EVT) product derived from Landsat 8. Not only did our product more accurately classify fire fuels but was also able to identify 20 dominant vegetation classes (percent cover \u3e1%) while the EVT product only identified 8 dominant classes within the study area. This study demonstrated that highly detailed and accurate fire fuel maps can be created at local sites where AVIRIS-NG is available and can provide valuable decision-support information to fire managers to combat wildfires

SLc7a8 is a key amino acids supplier for the metabolic programs that sustain homeostasis and activation of type 2 innate lymphoid cells

Group 2 innate lymphoid cells (ILC2) are innate counterparts of T helper 2 (Th2) cells that maintain tissue homeostasis and respond to injuries through rapid interleukin (IL)-5 and IL-13 secretion. ILC2s depend on availability of arginine and branched-chain amino acids for sustaining cellular fitness, proliferation, and cytokine secretion in both steady state and upon activation. However, the contribution of amino acid transporters to ILC2 functions is not known. Here, we found that ILC2s selectively expres

The aryl hydrocarbon receptor instructs the immunomodulatory profile of a subset of Clec4a4 eosinophils unique to the small intestine

C-type lectin domain family 4, member a4 (Clec4a4) is a C-type lectin inhibitory receptor specific for glycans thought to be exclusively expressed on murine CD8α− conventional dendritic cells. Using newly generated Clec4a4-mCherry knock-in mice, we identify a subset of Clec4a4-expressing eosinophils uniquely localized in the small intestine lamina propria. Clec4a4+ eosinophils evinced an immunomodulatory signature, whereas Clec4a4− eosinophils manifested a proinflammatory profile. Clec4a4+ eosinophils expressed high levels of aryl hydrocarbon receptor (Ahr), which drove the expression of Clec4a4 as well as other immunomodulatory features, such as PD-L1. The abundance of Clec4a4+ eosinophils was dependent on dietary AHR ligands, increased with aging, and declined in inflammatory conditions. Mice lacking AHR in eosinophils expanded innate lymphoid cells of type 2 and cleared Nippostrongylus brasiliensis infection more effectively than did wild-type mice. These results highlight the heterogeneity of eosinophils in response to tissue cues and identify a unique AHR-dependent subset of eosinophils in the small intestine with an immunomodulatory profile

Northern Hemisphere permafrost map based on TTOP modelling for 2000-2016 at 1 km²scale

Permafrost is a key element of the cryosphere and an essential climate variable in the Global Climate Observing System. There is no remote-sensing method available to reliably monitor the permafrost thermal state. To estimate permafrost distribution at a hemispheric scale, we employ an equilibrium state model for the temperature at the top of the permafrost (TTOP model) for the 2000–2016 period, driven by remotely-sensed land surface temperatures, down-scaled ERA-Interim climate reanalysis data, tundra wetness classes and landcover map from the ESA Landcover Climate Change Initiative (CCI) project. Subgrid variability of ground temperatures due to snow and landcover variability is represented in the model using subpixel statistics. The results are validated against borehole measurements and reviewed regionally. The accuracy of the modelled mean annual ground temperature (MAGT) at the top of the permafrost is ±2 °C when compared to permafrost borehole data. The modelled permafrost area (MAGT 0) is around 21 × 106 km2 (22% of exposed land area), which is approximately 2 × 106 km2 less than estimated previously. Detailed comparisons at a regional scale show that the model performs well in sparsely vegetated tundra regions and mountains, but is less accurate in densely vegetated boreal spruce and larch forests

Northern Hemisphere permafrost map based on TTOP modelling for 2000–2016 at 1 km2 scale

Permafrost is a key element of the cryosphere and an essential climate variable in the Global Climate Observing System. There is no remote-sensing method available to reliably monitor the permafrost thermal state. To estimate permafrost distribution at a hemispheric scale, we employ an equilibrium state model for the temperature at the top of the permafrost (TTOP model) for the 2000–2016 period, driven by remotely- sensed land surface temperatures, down-scaled ERA-Interim climate reanalysis data, tundra wetness classes and landcover map from the ESA Landcover Climate Change Initiative (CCI) project. Subgrid variability of ground temperatures due to snow and landcover variability is represented in the model using subpixel statistics. The results are validated against borehole measurements and reviewed regionally. The accuracy of the modelled mean annual ground temperature (MAGT) at the top of the permafrost is ±2 °C when compared to permafrost borehole data. The modelled permafrost area (MAGT 0) is around 21 × 106 km2 (22% of exposed land area), which is approximately 2 × 106 km2 less than estimated previously. Detailed comparisons at a regional scale show that the model performs well in sparsely vegetated tundra regions and mountains, but is less accurate in densely vegetated boreal spruce and larch forests