Matching Items (1,894)
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Endolithic microbial communities are prominent features of intertidal marine habitats, where they colonize a variety of substrates, contributing to their erosion. Almost 2 centuries worth of naturalistic studies focused on a few true-boring (euendolithic) phototrophs, but substrate preference has received little attention. The Isla de Mona (Puerto Rico) intertidal zone

Endolithic microbial communities are prominent features of intertidal marine habitats, where they colonize a variety of substrates, contributing to their erosion. Almost 2 centuries worth of naturalistic studies focused on a few true-boring (euendolithic) phototrophs, but substrate preference has received little attention. The Isla de Mona (Puerto Rico) intertidal zone offers a unique setting to investigate substrate specificity of endolithic communities since various phosphate rock, limestone and dolostone outcrops occur there. High-throughput 16S rDNA genetic sampling, enhanced by targeted cultivation, revealed that, while euendolithic cyanobacteria were dominant operational taxonomic units (OTUs), the communities were invariably of high diversity, well beyond that reported in traditional studies and implying an unexpected metabolic complexity potentially contributed by secondary colonizers. While the overall community composition did not show differences traceable to the nature of the mineral substrate, we detected specialization among particular euendolithic cyanobacterial clades towards the type of substrate they excavate but only at the OTU phylogenetic level, implying that close relatives have specialized recurrently into particular substrates. The cationic mineral component was determinant in this preference, suggesting the existence in nature of alternatives to the boring mechanism described in culture that is based exclusively on transcellular calcium transport.

ContributorsCouradeau, Estelle (Author) / Roush, Daniel (Author) / Guida, Brandon (Author) / Garcia-Pichel, Ferran (Author) / College of Liberal Arts and Sciences (Contributor)
Created2017-01-23
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Norwegian protected areas have historically been managed by central, expertise bureaucracy; however, a governance change in 2010 decentralized and delegated the right to manage protected areas to locally elected politicians and elected Sámi representatives in newly established National Park Boards. We explore how this new governance change affects adaptive capacity

Norwegian protected areas have historically been managed by central, expertise bureaucracy; however, a governance change in 2010 decentralized and delegated the right to manage protected areas to locally elected politicians and elected Sámi representatives in newly established National Park Boards. We explore how this new governance change affects adaptive capacity within the reindeer industry, as the reindeer herders are now participating with other users in decision-making processes related to large tracts of protected areas in which they have pasture access. Aspects within adaptive capacity and resilience thinking are useful as complementary dimensions to a social-ecological system framework (Ostrom 2007) in exploring the dynamics of complex adaptive social-ecological systems. The National Park Board provides a novel example of adaptive governance that can foster resilient livelihoods for various groups of actors that depend on protected areas. Data for this paper were gathered primarily through observation in National Park Board meetings, focus groups, and qualitative interviews with reindeer herders and other key stakeholders. We have identified certain aspects of the national park governance that may serve as sources of resilience and adaptive capacity for the natural system and pastoral people that rely on using these areas. The regional National Park Board is as such a critical mechanism that provides an action arena for participation and conflict resolution. However, desired outcomes such as coproduction of knowledge, social learning, and increased adaptive capacity within reindeer husbandry have not been actualized at this time. The challenge with limited scope of action in the National Park Board and a mismatch between what is important for the herders and what is addressed in the National Park Board become important for the success of this management model.

ContributorsRisvoll, Camilla (Author) / Fedreheim, Gunn Elin (Author) / Sandberg, Audun (Author) / BurnSilver, Shauna (Author) / College of Liberal Arts and Sciences (Contributor)
Created2014
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Description

Coordinated drilling efforts are an important method to investigate active tectonics and magmatic processes related to faults and volcanoes. The US National Science Foundation (NSF) recently sponsored a series of workshops to define the nature of future continental drilling efforts. As part of this series, we convened a workshop to

Coordinated drilling efforts are an important method to investigate active tectonics and magmatic processes related to faults and volcanoes. The US National Science Foundation (NSF) recently sponsored a series of workshops to define the nature of future continental drilling efforts. As part of this series, we convened a workshop to explore how continental scientific drilling can be used to better understand active tectonic and magmatic processes. The workshop, held in Park City, Utah, in May 2013, was attended by 41 investigators from seven countries. Participants were asked to define compelling scientific justifications for examining problems that can be addressed by coordinated programs of continental scientific drilling and related site investigations. They were also asked to evaluate a wide range of proposed drilling projects, based on white papers submitted prior to the workshop.

Participants working on faults and fault zone processes highlighted two overarching topics with exciting potential for future scientific drilling research: (1) the seismic cycle and (2) the mechanics and architecture of fault zones. Recommended projects target fundamental mechanical processes and controls on faulting, and range from induced earthquakes and earthquake initiation to investigations of detachment fault mechanics and fluid flow in fault zones. Participants working on active volcanism identified five themes: the volcano eruption cycle; eruption sustainability, near-field stresses, and system recovery; eruption hazards; verification of geophysical models; and interactions with other Earth systems. Recommended projects address problems that are transferrable to other volcanic systems, such as improved methods for identifying eruption history and constraining the rheological structure of shallow caldera regions. Participants working on chemical geodynamics identified four major themes: large igneous provinces (LIPs), ocean islands, continental hotspot tracks and rifts, and convergent plate margins (subduction zones).

This workshop brought together a diverse group of scientists with a broad range of scientific experience and interests. A particular strength was the involvement of both early-career scientists, who will initiate and carry out these new research programs, and more senior researchers with many years of experience in scientific drilling and active tectonics research. Each of the themes and questions outlined above has direct benefits to society, including improving hazard assessment, direct monitoring of active systems for early warning, renewable and non-renewable resource and energy exploitation, and predicting the environmental impacts of natural hazards, emphasizing the central role that scientific drilling will play in future scientific and societal developments.

ContributorsShervais, J. (Author) / Evans, J. (Author) / Toy, V. (Author) / Kirkpatrick, J. (Author) / Clarke, Amanda (Author) / Eichelberger, J. (Author) / College of Liberal Arts and Sciences (Contributor)
Created2014-12-22
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Recent studies provide compelling evidence for the idea that creative thinking draws upon two kinds of processes linked to distinct physiological features, and stimulated under different conditions. In short, the fast system-I produces intuition whereas the slow and deliberate system-II produces reasoning. System-I can help see novel solutions and associations

Recent studies provide compelling evidence for the idea that creative thinking draws upon two kinds of processes linked to distinct physiological features, and stimulated under different conditions. In short, the fast system-I produces intuition whereas the slow and deliberate system-II produces reasoning. System-I can help see novel solutions and associations instantaneously, but is prone to error. System-II has other biases, but can help checking and modifying the system-I results. Although thinking is the core business of science, the accepted ways of doing our work focus almost entirely on facilitating system-II. We discuss the role of system-I thinking in past scientific breakthroughs, and argue that scientific progress may be catalyzed by creating conditions for such associative intuitive thinking in our academic lives and in education. Unstructured socializing time, education for daring exploration, and cooperation with the arts are among the potential elements. Because such activities may be looked upon as procrastination rather than work, deliberate effort is needed to counteract our systematic bias.

ContributorsScheffer, Marten (Author) / Bascompte, Jordi (Author) / Bjordam, Tone K. (Author) / Carpenter, Stephen R. (Author) / Clarke, Laurie B. (Author) / Folke, Carl (Author) / Marquet, Pablo (Author) / Mazzeo, Nestor (Author) / Meerhoff, Mariana (Author) / Sala, Osvaldo (Author) / Westley, Frances R. (Author) / College of Liberal Arts and Sciences (Contributor)
Created2015
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Human populations differ reliably in the degree to which people favor family, friends, and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review

Human populations differ reliably in the degree to which people favor family, friends, and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories for cross-population differences in parochialism.

ContributorsHruschka, Daniel (Author) / Henrich, Joseph (Author) / College of Liberal Arts and Sciences (Contributor)
Created2013-09-11
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Description

Embodiment theory proposes that knowledge is grounded in sensorimotor systems, and that learning can be facilitated to the extent that lessons can be mapped to these systems. This study with 109 college-age participants addresses two overarching questions: (a) how are immediate and delayed learning gains affected by the degree to

Embodiment theory proposes that knowledge is grounded in sensorimotor systems, and that learning can be facilitated to the extent that lessons can be mapped to these systems. This study with 109 college-age participants addresses two overarching questions: (a) how are immediate and delayed learning gains affected by the degree to which a lesson is embodied, and (b) how do the affordances of three different educational platforms affect immediate and delayed learning? Six 50 min-long lessons on centripetal force were created. The first factor was the degree of embodiment with two levels: (1) low and (2) high. The second factor was platform with three levels: (1) a large scale “mixed reality” immersive environment containing both digital and hands-on components called SMALLab, (2) an interactive whiteboard system, and (3) a mouse-driven desktop computer.

Pre-tests, post-tests, and 1-week follow-up (retention or delayed learning gains) tests were administered resulting in a 2 × 3 × 3 design. Two knowledge subtests were analyzed, one that relied on more declarative knowledge and one that relied on more generative knowledge, e.g., hand-drawing vectors. Regardless of condition, participants made significant immediate learning gains from pre-test to post-test. There were no significant main effects or interactions due to platform or embodiment on immediate learning. However, from post-test to follow-up the level of embodiment interacted significantly with time, such that participants in the high embodiment conditions performed better on the subtest devoted to generative knowledge questions. We posit that better retention of certain types of knowledge can be seen over time when more embodiment is present during the encoding phase. This sort of retention may not appear on more traditional factual/declarative tests. Educational technology designers should consider using more sensorimotor feedback and gestural congruency when designing and opportunities for instructor professional development need to be provided as well.

Created2016-11-25
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The maternal separation (MS) paradigm is an animal model of early life stress. Animals subjected to MS during the first 2 weeks of life display altered behavioral and neuroendocrinological stress responses as adults. MS also produces altered responsiveness to and self-administration (SA) of various drugs of abuse including cocaine, ethanol,

The maternal separation (MS) paradigm is an animal model of early life stress. Animals subjected to MS during the first 2 weeks of life display altered behavioral and neuroendocrinological stress responses as adults. MS also produces altered responsiveness to and self-administration (SA) of various drugs of abuse including cocaine, ethanol, and amphetamine. However, no studies have yet examined the effects of MS on methamphetamine (METH) SA. This study was performed to examine the effects of MS on the acquisition of METH SA, extinction, and reinstatement of METH-seeking behavior in adulthood. Given the known influence of early life stress and drug exposure on epigenetic processes, we also investigated group differences in levels of the epigenetic marker methyl CpG binding protein 2 (MeCP2) in the nucleus accumbens (NAc) core. Long–Evans pups and dams were separated on postnatal days (PND) 2–14 for either 180 (MS180) or 15 min (MS15). Male offspring were allowed to acquire METH SA (0.05 mg/kg/infusion) in 15 2-h daily sessions starting at PND67, followed by extinction training and cue-induced reinstatement of METH-seeking behavior. Rats were then assessed for MeCP2 levels in the NAc core by immunohistochemistry. The MS180 group self-administered significantly more METH and acquired SA earlier than the MS15 group. No group differences in extinction or cue-induced reinstatement were observed. MS15 rats had significantly elevated MeCP2-immunoreactive cells in the NAc core as compared to MS180 rats. Together, these data suggest that MS has lasting influences on METH SA as well as epigenetic processes in the brain reward circuitry.

ContributorsLewis, Candace (Author) / Staudinger, Kelsey (Author) / Scheck, Lena (Author) / Olive, M. Foster (Author) / College of Liberal Arts and Sciences (Contributor)
Created2013-06-17
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Description

A realistic simulation of snow cover and its thermal properties are important for accurate modelling of permafrost. We analyse simulated relationships between air and near-surface (20  cm) soil temperatures in the Northern Hemisphere permafrost region during winter, with a particular focus on snow insulation effects in nine land surface models,

A realistic simulation of snow cover and its thermal properties are important for accurate modelling of permafrost. We analyse simulated relationships between air and near-surface (20  cm) soil temperatures in the Northern Hemisphere permafrost region during winter, with a particular focus on snow insulation effects in nine land surface models, and compare them with observations from 268 Russian stations. There are large cross-model differences in the simulated differences between near-surface soil and air temperatures (ΔT; 3 to 14 °C), in the sensitivity of soil-to-air temperature (0.13 to 0.96 °C °C-1), and in the relationship between ΔT and snow depth. The observed relationship between ΔT and snow depth can be used as a metric to evaluate the effects of each model's representation of snow insulation, hence guide improvements to the model's conceptual structure and process parameterisations. Models with better performance apply multilayer snow schemes and consider complex snow processes. Some models show poor performance in representing snow insulation due to underestimation of snow depth and/or overestimation of snow conductivity. Generally, models identified as most acceptable with respect to snow insulation simulate reasonable areas of near-surface permafrost (13.19 to 15.77 million  km2). However, there is not a simple relationship between the sophistication of the snow insulation in the acceptable models and the simulated area of Northern Hemisphere near-surface permafrost, because several other factors, such as soil depth used in the models, the treatment of soil organic matter content, hydrology and vegetation cover, also affect the simulated permafrost distribution.

ContributorsWang, Wenli (Author) / Rinke, Annette (Author) / Moore, John C. (Author) / Ji, Duoying (Author) / Cui, Xuefeng (Author) / Peng, Shushi (Author) / Lawrence, David M. (Author) / McGuire, A. David (Author) / Burke, Eleanor J. (Author) / Chen, Xiaodong (Author) / Decharme, Bertrand (Author) / Koven, Charles (Author) / MacDougall, Andrew (Author) / Saito, Kazuyuki (Author) / Zhang, Wenxin (Author) / Alkama, Ramdane (Author) / Bohn, Theodore (Author) / Ciais, Philippe (Author) / Delire, Christine (Author) / Gouttevin, Isabelle (Author) / Hajima, Tomohiro (Author) / Krinner, Gerhard (Author) / Lettenmaier, Dennis P. (Author) / Miller, Paul A. (Author) / Smith, Benjamin (Author) / Sueyoshi, Tetsuo (Author) / Sherstiukov, Artem B. (Author) / College of Liberal Arts and Sciences (Contributor)
Created2016-08-11
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Description

The catalytic hydrogenation of nitroarenes is an environmentally benign technology for the production of anilines, which are key intermediates for manufacturing agrochemicals, pharmaceuticals and dyes. Most of the precious metal catalysts, however, suffer from low chemoselectivity when one or more reducible groups are present in a nitroarene molecule. Herein we

The catalytic hydrogenation of nitroarenes is an environmentally benign technology for the production of anilines, which are key intermediates for manufacturing agrochemicals, pharmaceuticals and dyes. Most of the precious metal catalysts, however, suffer from low chemoselectivity when one or more reducible groups are present in a nitroarene molecule. Herein we report FeOx-supported platinum single-atom and pseudo-single-atom structures as highly active, chemoselective and reusable catalysts for hydrogenation of a variety of substituted nitroarenes. For hydrogenation of 3-nitrostyrene, the catalyst yields a TOF of ~1,500 h-1, 20-fold higher than the best result reported in literature, and a selectivity to 3-aminostyrene close to 99%, the best ever achieved over platinum group metals. The superior performance can be attributed to the presence of positively charged platinum centres and the absence of Pt–Pt metallic bonding, both of which favour the preferential adsorption of nitro groups.

ContributorsWei, Haisheng (Author) / Liu, Xiaoyan (Author) / Wang, Aiqin (Author) / Zhang, Leilei (Author) / Qiao, Botao (Author) / Yang, Xiaofeng (Author) / Huang, Yanqiang (Author) / Miao, Shu (Author) / Liu, Jingyue (Author) / Zhang, Tao (Author) / College of Liberal Arts and Sciences (Contributor)
Created2014-12-03
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Description

The Mars Science Laboratory landed in Gale crater on Mars in August 2012, and the Curiosity rover then began field studies on its drive toward Mount Sharp, a central peak made of ancient sediments. CheMin is one of ten instruments on or inside the rover, all designed to provide detailed

The Mars Science Laboratory landed in Gale crater on Mars in August 2012, and the Curiosity rover then began field studies on its drive toward Mount Sharp, a central peak made of ancient sediments. CheMin is one of ten instruments on or inside the rover, all designed to provide detailed information on the rocks, soils and atmosphere in this region. CheMin is a miniaturized X-ray diffraction/X-ray fluorescence (XRD/XRF) instrument that uses transmission geometry with an energy-discriminating CCD detector. CheMin uses onboard standards for XRD and XRF calibration, and beryl:quartz mixtures constitute the primary XRD standards. Four samples have been analysed by CheMin, namely a soil sample, two samples drilled from mudstones and a sample drilled from a sandstone. Rietveld and full-pattern analysis of the XRD data reveal a complex mineralogy, with contributions from parent igneous rocks, amorphous components and several minerals relating to aqueous alteration. In particular, the mudstone samples all contain one or more phyllosilicates consistent with alteration in liquid water. In addition to quantitative mineralogy, Rietveld refinements also provide unit-cell parameters for the major phases, which can be used to infer the chemical compositions of individual minerals and, by difference, the composition of the amorphous component.

ContributorsBish, David (Author) / Blake, David (Author) / Vaniman, David (Author) / Sarrazin, Philippe (Author) / Bristow, Thomas (Author) / Achilles, Cherie (Author) / Dera, Przemyslaw (Author) / Chipera, Steve (Author) / Crisp, Joy (Author) / Downs, R. T. (Author) / Farmer, Jack (Author) / Gailhanou, Marc (Author) / Ming, Doug (Author) / Morookian, John Michael (Author) / Morris, Richard (Author) / Morrison, Shaunna (Author) / Rampe, Elizabeth (Author) / Treiman, Allan (Author) / Yen, Albert (Author) / College of Liberal Arts and Sciences (Contributor)
Created2014-10-21