Matching Items (889)
Filtering by

Clear all filters

128190-Thumbnail Image.png
Description

We present a novel paradigm to identify shared and unique brain regions underlying non-semantic, non-phonological, abstract, audio-visual (AV) memory vs. naming using a longitudinal functional magnetic resonance imaging experiment. Participants were trained to associate novel AV stimulus pairs containing hidden linguistic content. Half of the stimulus pairs were distorted images

We present a novel paradigm to identify shared and unique brain regions underlying non-semantic, non-phonological, abstract, audio-visual (AV) memory vs. naming using a longitudinal functional magnetic resonance imaging experiment. Participants were trained to associate novel AV stimulus pairs containing hidden linguistic content. Half of the stimulus pairs were distorted images of animals and sine-wave speech versions of the animal's name. Images and sounds were distorted in such a way as to make their linguistic content easily recognizable only after being made aware of its existence. Memory for the pairings was tested by presenting an AV pair and asking participants to verify if the two stimuli formed a learned pairing. After memory testing, the hidden linguistic content was revealed and participants were tested again on their recollection of the pairings in this linguistically informed state. Once informed, the AV verification task could be performed by naming the picture. There was substantial overlap between the regions involved in recognition of non-linguistic sensory memory and naming, suggesting a strong relation between them. Contrasts between sessions identified left angular gyrus and middle temporal gyrus as key additional players in the naming network. Left inferior frontal regions participated in both naming and non-linguistic AV memory suggesting the region is responsible for AV memory independent of phonological content contrary to previous proposals. Functional connectivity between angular gyrus and left inferior frontal gyrus and left middle temporal gyrus increased when performing the AV task as naming. The results are consistent with the hypothesis that, at the spatial resolution of fMRI, the regions that facilitate non-linguistic AV associations are a subset of those that facilitate naming though reorganized into distinct networks.

ContributorsSmith, Jason F. (Author) / Braun, Allen R. (Author) / Alexander, Gene E. (Author) / Chen, Kewei (Author) / Horwitz, Barry (Author) / College of Liberal Arts and Sciences (Contributor)
Created2013-10-11
128189-Thumbnail Image.png
Description

Hardships that face transmigrants working in agriculture include the potential for drug use. Reliant on village-based networks that facilitate border crossing and developing a plan for a destination within this country, transmigrants who try new drugs/alcohol and/or continue on accustomed drugs/alcohol are facilitated in these endeavors through locally generated networks

Hardships that face transmigrants working in agriculture include the potential for drug use. Reliant on village-based networks that facilitate border crossing and developing a plan for a destination within this country, transmigrants who try new drugs/alcohol and/or continue on accustomed drugs/alcohol are facilitated in these endeavors through locally generated networks as alternative forms of access and support. Seven cases of undocumented men from Mexico are reviewed to show how use of illicit drugs is minimally affected by economic success and time in the United States, or village-based networks that first facilitated entry into this country. Prior conditions, especially childhood difficulties and search for socioeconomic autonomy, precipitate new and/or continuing drug use within the United States on this side of the border, where both forms of drug use are facilitated by locally generated networks.

ContributorsBletzer, Keith (Author) / College of Liberal Arts and Sciences (Contributor)
Created2017-02-28
128188-Thumbnail Image.png
Description

We assembled daily maximum and minimum temperature records for 31 stations throughout Iran over the period 1961-2010. As with many other areas of the world, we found that both the maximum and minimum temperatures were increasing overall with the minimum temperatures increasing twice as fast as the maximum temperatures. We

We assembled daily maximum and minimum temperature records for 31 stations throughout Iran over the period 1961-2010. As with many other areas of the world, we found that both the maximum and minimum temperatures were increasing overall with the minimum temperatures increasing twice as fast as the maximum temperatures. We gathered population data for the stations near the beginning and end of the temperature records and found in all seasons and for both the maximum and minimum temperatures the magnitude of population growth positively influenced the temperature trends. However, unlike so many other studies, we found the strongest population growth signal in the winter for the maximum temperatures. We found evidence that this winter-season population-temperature signal is related snow cover. Our results illustrate that any number of processes are involved in explaining trends in historical maximum and minimum temperature records.

Created2016-08-11
128187-Thumbnail Image.png
Description

Soil temperature (Ts) change is a key indicator of the dynamics of permafrost. On seasonal and interannual timescales, the variability of Ts determines the active-layer depth, which regulates hydrological soil properties and biogeochemical processes. On the multi-decadal scale, increasing Ts not only drives permafrost thaw/retreat but can also trigger and

Soil temperature (Ts) change is a key indicator of the dynamics of permafrost. On seasonal and interannual timescales, the variability of Ts determines the active-layer depth, which regulates hydrological soil properties and biogeochemical processes. On the multi-decadal scale, increasing Ts not only drives permafrost thaw/retreat but can also trigger and accelerate the decomposition of soil organic carbon. The magnitude of permafrost carbon feedbacks is thus closely linked to the rate of change of soil thermal regimes. In this study, we used nine process-based ecosystem models with permafrost processes, all forced by different observation-based climate forcing during the period 1960–2000, to characterize the warming rate of Ts in permafrost regions. There is a large spread of Ts trends at 20 cm depth across the models, with trend values ranging from 0.010 ± 0.003 to 0.031 ± 0.005 °C yr-1. Most models show smaller increase in Ts with increasing depth. Air temperature (Tsub>a) and longwave downward radiation (LWDR) are the main drivers of Ts trends, but their relative contributions differ amongst the models. Different trends of LWDR used in the forcing of models can explain 61 % of their differences in Ts trends, while trends of Ta only explain 5 % of the differences in Ts trends. Uncertain climate forcing contributes a larger uncertainty in Ts trends (0.021 ± 0.008 °C yr-1, mean ± standard deviation) than the uncertainty of model structure (0.012 ± 0.001 °C yr-1), diagnosed from the range of response between different models, normalized to the same forcing. In addition, the loss rate of near-surface permafrost area, defined as total area where the maximum seasonal active-layer thickness (ALT) is less than 3 m loss rate, is found to be significantly correlated with the magnitude of the trends of Ts at 1 m depth across the models (R = −0.85, P = 0.003), but not with the initial total near-surface permafrost area (R = −0.30, P = 0.438). The sensitivity of the total boreal near-surface permafrost area to Ts at 1 m is estimated to be of −2.80 ± 0.67 million km2°C-1. Finally, by using two long-term LWDR data sets and relationships between trends of LWDR and Ts across models, we infer an observation-constrained total boreal near-surface permafrost area decrease comprising between 39 ± 14  ×  103 and 75 ± 14  ×  103km2yr-1 from 1960 to 2000. This corresponds to 9–18 % degradation of the current permafrost area.

ContributorsPeng, S. (Author) / Ciais, P. (Author) / Krinner, G. (Author) / Wang, T. (Author) / Gouttevin, I. (Author) / McGuire, A. D. (Author) / Lawrence, D. (Author) / Burke, E. (Author) / Chen, X. (Author) / Decharme, B. (Author) / Koven, C. (Author) / MacDougall, A. (Author) / Rinke, A. (Author) / Saito, K. (Author) / Zhang, W. (Author) / Alkama, R. (Author) / Bohn, Theodore (Author) / Delire, C. (Author) / Hajima, T. (Author) / Ji, D. (Author) / Lettenmaier, D. P. (Author) / Miller, P. A. (Author) / Moore, J. C. (Author) / Smith, B. (Author) / Sueyoshi, T. (Author) / College of Liberal Arts and Sciences (Contributor)
Created2016-01-20
128185-Thumbnail Image.png
Description

The Sky View Factor (SVF) is a dimension-reduced representation of urban form and one of the major variables in radiation models that estimate outdoor thermal comfort. Common ways of retrieving SVFs in urban environments include capturing fisheye photographs or creating a digital 3D city or elevation model of the environment.

The Sky View Factor (SVF) is a dimension-reduced representation of urban form and one of the major variables in radiation models that estimate outdoor thermal comfort. Common ways of retrieving SVFs in urban environments include capturing fisheye photographs or creating a digital 3D city or elevation model of the environment. Such techniques have previously been limited due to a lack of imagery or lack of full scale detailed models of urban areas. We developed a web based tool that automatically generates synthetic hemispherical fisheye views from Google Earth at arbitrary spatial resolution and calculates the corresponding SVFs through equiangular projection. SVF results were validated using Google Maps Street View and compared to results from other SVF calculation tools. We generated 5-meter resolution SVF maps for two neighborhoods in Phoenix, Arizona to illustrate fine-scale variations of intra-urban horizon limitations due to urban form and vegetation. To demonstrate the utility of our synthetic fisheye approach for heat stress applications, we automated a radiation model to generate outdoor thermal comfort maps for Arizona State University’s Tempe campus for a hot summer day using synthetic fisheye photos and on-site meteorological data. Model output was tested against mobile transect measurements of the six-directional radiant flux density. Based on the thermal comfort maps, we implemented a pedestrian routing algorithm that is optimized for distance and thermal comfort preferences. Our synthetic fisheye approach can help planners assess urban design and tree planting strategies to maximize thermal comfort outcomes and can support heat hazard mitigation in urban areas.

ContributorsMiddel, Ariane (Author) / Lukasczyk, Jonas (Author) / Maciejewski, Ross (Author) / College of Liberal Arts and Sciences (Contributor)
Created2017-03-27
128183-Thumbnail Image.png
Description

Streamer biofilm communities (SBC) are often observed within chemosynthetic zones of Yellowstone hot spring outflow channels, where temperatures exceed those conducive to photosynthesis. Nearest the hydrothermal source (75–88°C) SBC comprise thermophilic Archaea and Bacteria, often mixed communities including Desulfurococcales and uncultured Crenarchaeota, as well as Aquificae and Thermus, each carrying

Streamer biofilm communities (SBC) are often observed within chemosynthetic zones of Yellowstone hot spring outflow channels, where temperatures exceed those conducive to photosynthesis. Nearest the hydrothermal source (75–88°C) SBC comprise thermophilic Archaea and Bacteria, often mixed communities including Desulfurococcales and uncultured Crenarchaeota, as well as Aquificae and Thermus, each carrying diagnostic membrane lipid biomarkers. We tested the hypothesis that SBC can alternate their metabolism between autotrophy and heterotrophy depending on substrate availability. Feeding experiments were performed at two alkaline hot springs in Yellowstone National Park: Octopus Spring and “Bison Pool,” using various 13C-labeled substrates (bicarbonate, formate, acetate, and glucose) to determine the relative uptake of these different carbon sources. Highest 13C uptake, at both sites, was from acetate into almost all bacterial fatty acids, particularly into methyl-branched C15, C17 and C19 fatty acids that are diagnostic for Thermus/Meiothermus, and some Firmicutes as well as into universally common C16:0 and C18:0 fatty acids. 13C-glucose showed a similar, but a 10–30 times lower uptake across most fatty acids. 13C-bicarbonate uptake, signifying the presence of autotrophic communities was only significant at “Bison Pool” and was observed predominantly in non-specific saturated C16, C18, C20, and C22 fatty acids. Incorporation of 13C-formate occurred only at very low rates at “Bison Pool” and was almost undetectable at Octopus Spring, suggesting that formate is not an important carbon source for SBC. 13C-uptake into archaeal lipids occurred predominantly with 13C-acetate, suggesting also that archaeal communities at both springs have primarily heterotrophic carbon assimilation pathways. We hypothesize that these communities are energy-limited and predominantly nurtured by input of exogenous organic material, with only a small fraction being sustained by autotrophic growth.

ContributorsSchubotz, Florence (Author) / Hays, Lindsay E. (Author) / Meyer-Dombard, D'Arcy R. (Author) / Gillespie, Aimee (Author) / Shock, Everett (Author) / Summons, Roger E. (Author) / College of Liberal Arts and Sciences (Contributor)
Created2015-02-05
128180-Thumbnail Image.png
Description

Protection by melanin depends on its subcellular location. Although most filamentous fungi synthesize melanin via a polyketide synthase pathway, where and how melanin biosynthesis occurs and how it is deposited as extracellular granules remain elusive. Using a forward genetic screen in the pathogen Aspergillus fumigatus, we find that mutations in

Protection by melanin depends on its subcellular location. Although most filamentous fungi synthesize melanin via a polyketide synthase pathway, where and how melanin biosynthesis occurs and how it is deposited as extracellular granules remain elusive. Using a forward genetic screen in the pathogen Aspergillus fumigatus, we find that mutations in an endosomal sorting nexin abolish melanin cell-wall deposition. We find that all enzymes involved in the early steps of melanin biosynthesis are recruited to endosomes through a non-conventional secretory pathway. In contrast, late melanin enzymes accumulate in the cell wall. Such subcellular compartmentalization of the melanin biosynthetic machinery occurs in both A. fumigatus and A. nidulans. Thus, fungal melanin biosynthesis appears to be initiated in endosomes with exocytosis leading to melanin extracellular deposition, much like the synthesis and trafficking of mammalian melanin in endosomally derived melanosomes.

ContributorsUpadhyay, Srijana (Author) / Xu, Xinping (Author) / Lowry, David (Author) / Jackson, Jennifer C. (Author) / Roberson, Robert (Author) / Lin, Xiaorong (Author) / College of Liberal Arts and Sciences (Contributor)
Created2016-03-10
128177-Thumbnail Image.png
Description

Synthetic cathinones, colloquially referred to as “bath salts,” are derivatives of the psychoactive alkaloid cathinone found in Catha edulis (Khat). Since the mid-to-late 2000s, these amphetamine-like psychostimulants have gained popularity amongst drug users due to their potency, low cost, ease of procurement, and constantly evolving chemical structures. Concomitant with their

Synthetic cathinones, colloquially referred to as “bath salts,” are derivatives of the psychoactive alkaloid cathinone found in Catha edulis (Khat). Since the mid-to-late 2000s, these amphetamine-like psychostimulants have gained popularity amongst drug users due to their potency, low cost, ease of procurement, and constantly evolving chemical structures. Concomitant with their increased use is the emergence of a growing collection of case reports of bizarre and dangerous behaviors, toxicity to numerous organ systems, and death. However, scientific information regarding the abuse liability of these drugs has been relatively slower to materialize. Recently we have published several studies demonstrating that laboratory rodents will readily self-administer the “first generation” synthetic cathinones methylenedioxypyrovalerone (MDPV) and methylone via the intravenous route, in patterns similar to those of methamphetamine. Under progressive ratio schedules of reinforcement, the rank order of reinforcing efficacy of these compounds is MDPV ≥ methamphetamine > methylone. MDPV and methylone, as well as the “second generation” synthetic cathinones α-pyrrolidinovalerophenone (α-PVP) and 4-methylethcathinone (4-MEC), also dose-dependently increase brain reward function. Collectively, these findings indicate that synthetic cathinones have a high abuse and addiction potential and underscore the need for future assessment of the extent and duration of neurotoxicity induced by these emerging drugs of abuse.

ContributorsWatterson, Lucas (Author) / Olive, M. Foster (Author) / College of Liberal Arts and Sciences (Contributor)
Created2014-06-04
128172-Thumbnail Image.png
Description

This transdisciplinary study (involving humanities, anthropology, linguistics, and philosophy) contrasts the reductionist ideological “top-down” focus on the construction of our cultural “world” with the meandering technical “bottom-up” approach, searching for forgotten or usually omitted aspects in current studies of culture. The discovery goes from the cultural “thing theory” to semiotics,

This transdisciplinary study (involving humanities, anthropology, linguistics, and philosophy) contrasts the reductionist ideological “top-down” focus on the construction of our cultural “world” with the meandering technical “bottom-up” approach, searching for forgotten or usually omitted aspects in current studies of culture. The discovery goes from the cultural “thing theory” to semiotics, to communication, and to the emergence of human language from the biosemiotic and zoosemiotic processes of communication, in order to examine the impact of these processes on human culture and cultural theories. Finally, based on “heretical ideas” of Jan Patočka and Martin Heidegger, some philosophical implications for the new humanism and for humanities are outlined.

ContributorsVolek, Emil (Author) / College of Liberal Arts and Sciences (Contributor)
Created2014-06