Showing papers by "University of Illinois at Urbana–Champaign published in 2013"
Posted Content•
TL;DR: The Satisfaction With Life Scale is narrowly focused to assess global life satisfaction and does not tap related constructs such as positive affect or loneliness, but is shown to have favorable psychometric properties, including high internal consistency and high temporal reliability.
Abstract: This article reports the development and validation of a scale to measure global life satisfaction, the Satisfaction With Life Scale (SWLS). Among the various components of subjective well-being, the SWLS is narrowly focused to assess global life satisfaction and does not tap related constructs such as positive affect or loneliness. The SWLS is shown to have favorable psychometric properties, including high internal consistency and high temporal reliability. Scores on the SWLS correlate moderately to highly with other measures of subjective well-being, and correlate predictably with specific personality characteristics. It is noted that the SWLS is suited for use with different age groups, and other potential uses of the scale are discussed.
21,449 citations
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TL;DR: Wilson's (1967) review of the area of subjective well-being (SWB) advanced several conclusions regarding those who report high levels of "happiness". A number of his conclusions have been overturned: youth and modest aspirations no longer are seen as prerequisites of SWB.
Abstract: W. Wilson's (1967) review of the area of subjective well-being (SWB) advanced several conclusions regarding those who report high levels of "happiness". A number of his conclusions have been overturned: youth and modest aspirations no longer are seen as prerequisites of SWB. E. Diener's (1984) review placed greater emphasis on theories that stressed psychological factors. In the current article, the authors review current evidence for Wilson's conclusions and discuss modern theories of SWB that stress dispositional influences, adaptation, goals, and coping strategies. The next steps in the evolution of the field are to comprehend the interaction of psychological factors with life circumstances in producing SWB, to understand the causal pathways leading to happiness, understand the processes underlying adaptation to events, and develop theories that explain why certain variables differentially influence the different components of SWV (life satisfaction, pleasant affect, and unpleasant affect).
9,254 citations
University of Illinois at Urbana–Champaign1, Joint Institute for the Study of the Atmosphere and Ocean2, Cooperative Institute for Research in Environmental Sciences3, University of Leeds4, University of Oslo5, United States Environmental Protection Agency6, University of Michigan7, Pacific Northwest National Laboratory8, German Aerospace Center9, United States Department of Energy10, Max Planck Society11, University of Tokyo12, National Oceanic and Atmospheric Administration13, Forschungszentrum Jülich14, Norwegian Meteorological Institute15, Indian Institute of Technology Bombay16, China Meteorological Administration17, Peking University18, Met Office19, Desert Research Institute20, Clarkson University21, Stanford University22, European Centre for Medium-Range Weather Forecasts23, International Institute of Minnesota24, Goddard Institute for Space Studies25, Yale University26, University of Washington27, University of California, Irvine28
TL;DR: In this paper, the authors provided an assessment of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice.
Abstract: Black carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr−1 in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m−2 with 90% uncertainty bounds of (+0.08, +1.27) W m−2. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W m−2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial-era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m−2 with 90% uncertainty bounds of +0.17 to +2.1 W m−2. Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm the climate. We estimate that black carbon, with a total climate forcing of +1.1 W m−2, is the second most important human emission in terms of its climate forcing in the present-day atmosphere; only carbon dioxide is estimated to have a greater forcing. Sources that emit black carbon also emit other short-lived species that may either cool or warm climate. Climate forcings from co-emitted species are estimated and used in the framework described herein. When the principal effects of short-lived co-emissions, including cooling agents such as sulfur dioxide, are included in net forcing, energy-related sources (fossil fuel and biofuel) have an industrial-era climate forcing of +0.22 (−0.50 to +1.08) W m−2 during the first year after emission. For a few of these sources, such as diesel engines and possibly residential biofuels, warming is strong enough that eliminating all short-lived emissions from these sources would reduce net climate forcing (i.e., produce cooling). When open burning emissions, which emit high levels of organic matter, are included in the total, the best estimate of net industrial-era climate forcing by all short-lived species from black-carbon-rich sources becomes slightly negative (−0.06 W m−2 with 90% uncertainty bounds of −1.45 to +1.29 W m−2). The uncertainties in net climate forcing from black-carbon-rich sources are substantial, largely due to lack of knowledge about cloud interactions with both black carbon and co-emitted organic carbon. In prioritizing potential black-carbon mitigation actions, non-science factors, such as technical feasibility, costs, policy design, and implementation feasibility play important roles. The major sources of black carbon are presently in different stages with regard to the feasibility for near-term mitigation. This assessment, by evaluating the large number and complexity of the associated physical and radiative processes in black-carbon climate forcing, sets a baseline from which to improve future climate forcing estimates.
4,591 citations
Posted Content•
TL;DR: The Satisfaction With Life Scale (SWLS) as discussed by the authors was developed to assess satisfaction with the respondent's life as a whole, which does not assess the individual's satisfaction with life domains such as health or mental health but allows subjects to integrate and weight these domains in whatever way they choose.
Abstract: The Satisfaction With Life Scale (SWLS) was developed to assess satisfaction with the respondent’s life as a whole. The scale does not assess satisfaction with life domains such as health or finances but allows subjects to integrate and weight these domains in whatever way they choose. Normative data are presented for the scale, which shows good convergent validity with other scales and with other types of assessments of subjective well-being. Life satisfaction as assessed by the SWLS shows a degree of temporal stability (e.g., 0.54 for 4 years), yet the SWLS has shown sufficient sensitivity to be potentially valuable to detect change in life satisfaction during the course of clinical intervention. Further, the scale shows discriminant validity from emotional well-being measures. The SWLS is recommended as a complement to scales that focus on psychopathology or emotional well-being because it assesses an individuals’ conscious evaluative judgment of his or her life by using the person’s own criteria.
4,255 citations
TL;DR: In this paper, the authors present the current status and implementation of battery chargers, charging power levels, and infrastructure for plug-in electric vehicles and hybrid vehicles and classify them into off-board and on-board types with unidirectional or bidirectional power flow.
Abstract: This paper reviews the current status and implementation of battery chargers, charging power levels, and infrastructure for plug-in electric vehicles and hybrids. Charger systems are categorized into off-board and on-board types with unidirectional or bidirectional power flow. Unidirectional charging limits hardware requirements and simplifies interconnection issues. Bidirectional charging supports battery energy injection back to the grid. Typical on-board chargers restrict power because of weight, space, and cost constraints. They can be integrated with the electric drive to avoid these problems. The availability of charging infrastructure reduces on-board energy storage requirements and costs. On-board charger systems can be conductive or inductive. An off-board charger can be designed for high charging rates and is less constrained by size and weight. Level 1 (convenience), Level 2 (primary), and Level 3 (fast) power levels are discussed. Future aspects such as roadbed charging are presented. Various power level chargers and infrastructure configurations are presented, compared, and evaluated based on amount of power, charging time and location, cost, equipment, and other factors.
2,327 citations
27 Oct 2013
TL;DR: A series of new latent semantic models with a deep structure that project queries and documents into a common low-dimensional space where the relevance of a document given a query is readily computed as the distance between them are developed.
Abstract: Latent semantic models, such as LSA, intend to map a query to its relevant documents at the semantic level where keyword-based matching often fails In this study we strive to develop a series of new latent semantic models with a deep structure that project queries and documents into a common low-dimensional space where the relevance of a document given a query is readily computed as the distance between them The proposed deep structured semantic models are discriminatively trained by maximizing the conditional likelihood of the clicked documents given a query using the clickthrough data To make our models applicable to large-scale Web search applications, we also use a technique called word hashing, which is shown to effectively scale up our semantic models to handle large vocabularies which are common in such tasks The new models are evaluated on a Web document ranking task using a real-world data set Results show that our best model significantly outperforms other latent semantic models, which were considered state-of-the-art in the performance prior to the work presented in this paper
1,935 citations
Joint Genome Institute1, Bielefeld University2, University of California, Davis3, University of Technology, Sydney4, Bigelow Laboratory For Ocean Sciences5, University of British Columbia6, University of Nevada, Las Vegas7, University of Patras8, Woods Hole Oceanographic Institution9, University of Illinois at Urbana–Champaign10, University of Queensland11
TL;DR: This study applies single-cell genomics to target and sequence 201 archaeal and bacterial cells from nine diverse habitats belonging to 29 major mostly uncharted branches of the tree of life and provides a systematic step towards a better understanding of biological evolution on the authors' planet.
Abstract: Genome sequencing enhances our understanding of the biological world by providing blueprints for the evolutionary and functional diversity that shapes the biosphere. However, microbial genomes that are currently available are of limited phylogenetic breadth, owing to our historical inability to cultivate most microorganisms in the laboratory. We apply single-cell genomics to target and sequence 201 uncultivated archaeal and bacterial cells from nine diverse habitats belonging to 29 major mostly uncharted branches of the tree of life, so-called 'microbial dark matter'. With this additional genomic information, we are able to resolve many intra- and inter-phylum-level relationships and to propose two new superphyla. We uncover unexpected metabolic features that extend our understanding of biology and challenge established boundaries between the three domains of life. These include a novel amino acid use for the opal stop codon, an archaeal-type purine synthesis in Bacteria and complete sigma factors in Archaea similar to those in Bacteria. The single-cell genomes also served to phylogenetically anchor up to 20% of metagenomic reads in some habitats, facilitating organism-level interpretation of ecosystem function. This study greatly expands the genomic representation of the tree of life and provides a systematic step towards a better understanding of biological evolution on our planet.
1,856 citations
TL;DR: This paper addresses the problem of learning similarity-preserving binary codes for efficient similarity search in large-scale image collections by proposing a simple and efficient alternating minimization algorithm, dubbed iterative quantization (ITQ), and demonstrating an application of ITQ to learning binary attributes or "classemes" on the ImageNet data set.
Abstract: This paper addresses the problem of learning similarity-preserving binary codes for efficient similarity search in large-scale image collections. We formulate this problem in terms of finding a rotation of zero-centered data so as to minimize the quantization error of mapping this data to the vertices of a zero-centered binary hypercube, and propose a simple and efficient alternating minimization algorithm to accomplish this task. This algorithm, dubbed iterative quantization (ITQ), has connections to multiclass spectral clustering and to the orthogonal Procrustes problem, and it can be used both with unsupervised data embeddings such as PCA and supervised embeddings such as canonical correlation analysis (CCA). The resulting binary codes significantly outperform several other state-of-the-art methods. We also show that further performance improvements can result from transforming the data with a nonlinear kernel mapping prior to PCA or CCA. Finally, we demonstrate an application of ITQ to learning binary attributes or "classemes" on the ImageNet data set.
1,697 citations
Pacific Northwest National Laboratory1, California Institute of Technology2, Princeton University3, Humboldt University of Berlin4, Pennsylvania State University5, Brookhaven National Laboratory6, University of California, Riverside7, University of Illinois at Urbana–Champaign8, United States Department of Energy9, University of California, Berkeley10, University of Toronto11, University of Michigan12, University of Amsterdam13, Utah State University14, Max Planck Society15, Louisiana State University16
TL;DR: Providing a future energy supply that is secure and CO_2-neutral will require switching to nonfossil energy sources such as wind, solar, nuclear, and geothermal energy and developing methods for transforming the energy produced by these new sources into forms that can be stored, transported, and used upon demand.
Abstract: Two major energy-related problems confront the world in the
next 50 years. First, increased worldwide competition for
gradually depleting fossil fuel reserves (derived from past
photosynthesis) will lead to higher costs, both monetarily and politically. Second, atmospheric CO_2 levels are at their highest recorded level since records began. Further increases are predicted to produce large and uncontrollable impacts on the world climate. These projected impacts extend beyond climate to ocean acidification, because the ocean is a major sink for atmospheric CO2.1 Providing a future energy supply that is secure and CO_2-neutral will require switching to nonfossil energy sources such as wind, solar, nuclear, and geothermal energy and developing methods for transforming the energy produced by these new sources into forms that can be stored, transported, and used upon demand.
1,651 citations
Alternatives1, John Innes Centre2, University of Bonn3, University of North Carolina at Chapel Hill4, University of Wisconsin-Madison5, University of Utah6, University of Southern California7, University of Edinburgh8, University of Warwick9, Harvard University10, University College Cork11, University of Queensland12, University of Hertfordshire13, University of Potsdam14, University of California, San Diego15, Goethe University Frankfurt16, University of California, San Francisco17, University of Delaware18, Uppsala University19, Medical University of Vienna20, J. Craig Venter Institute21, University of Hawaii at Manoa22, Leibniz Association23, University of Iowa24, University of Aberdeen25, Georgia Institute of Technology26, University of California, Berkeley27, University of Groningen28, Princeton University29, University of Marburg30, University of Illinois at Urbana–Champaign31, Saarland University32, Norwegian University of Life Sciences33, Massey University34, Toyama Prefectural University35, ETH Zurich36, University of Saskatchewan37, Rutgers University38, Scripps Research Institute39, University of Helsinki40, Texas A&M University41, National Institutes of Health42, Technical University of Berlin43, University of Otago44, University of Cambridge45, University of Alberta46, Michigan State University47, Hofstra University48
TL;DR: This review presents recommended nomenclature for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), a rapidly growing class of natural products.
1,560 citations
TL;DR: Graphene is a two-dimensional (2D) material with over 100-fold anisotropy of heat flow between the in-plane and out-of-plane directions.
Abstract: Graphene is a two-dimensional (2D) material with over 100-fold anisotropy of heat flow between the in-plane and out-of-plane directions. High in-plane thermal conductivity is due to covalent sp2 bonding between carbon atoms, whereas out-of-plane heat flow is limited by weak van der Waals coupling. Herein, we review the thermal properties of graphene, including its specific heat and thermal conductivity (from diffusive to ballistic limits) and the influence of substrates, defects, and other atomic modifications. We also highlight practical applications in which the thermal properties of graphene play a role. For instance, graphene transistors and interconnects benefit from the high in-plane thermal conductivity, up to a certain channel length. However, weak thermal coupling with substrates implies that interfaces and contacts remain significant dissipation bottlenecks. Heat flow in graphene or graphene composites could also be tunable through a variety of means, including phonon scattering by substrates, edges or interfaces. Ultimately, the unusual thermal properties of graphene stem from its 2D nature, forming a rich playground for new discoveries of heat flow physics and potentially leading to novel thermal management applications.
TL;DR: This work introduces a set of materials and design concepts for a rechargeable lithium ion battery technology that exploits thin, low modulus silicone elastomers as substrates, with a segmented design in the active materials, and unusual 'self-similar' interconnect structures between them.
Abstract: An important trend in electronics involves the development of materials, mechanical designs and manufacturing strategies that enable the use of unconventional substrates, such as polymer films, metal foils, paper sheets or rubber slabs. The last possibility is particularly challenging because the systems must accommodate not only bending but also stretching. Although several approaches are available for the electronics, a persistent difficulty is in power supplies that have similar mechanical properties, to allow their co-integration with the electronics. Here we introduce a set of materials and design concepts for a rechargeable lithium ion battery technology that exploits thin, low modulus silicone elastomers as substrates, with a segmented design in the active materials, and unusual ‘self-similar’ interconnect structures between them. The result enables reversible levels of stretchability up to 300%, while maintaining capacity densities of B1.1 mAh cm � 2 . Stretchable wireless power transmission systems provide the means to charge these types of batteries, without direct physical contact.
TL;DR: This Review summarized the current knowledge of oxidative stress in Escherichia coli, the model organism for which the understanding of damage and defence is most well developed, and proposed strategies to protect themselves with scavenging enzymes and repair systems.
Abstract: Oxic environments are hazardous. Molecular oxygen adventitiously abstracts electrons from many redox enzymes, continuously forming intracellular superoxide and hydrogen peroxide. These species can destroy the activities of metalloenzymes and the integrity of DNA, forcing organisms to protect themselves with scavenging enzymes and repair systems. Nevertheless, elevated levels of oxidants quickly poison bacteria, and both microbial competitors and hostile eukaryotic hosts exploit this vulnerability by assaulting these bacteria with peroxides or superoxide-forming antibiotics. In response, bacteria activate elegant adaptive strategies. In this Review, I summarize our current knowledge of oxidative stress in Escherichia coli, the model organism for which our understanding of damage and defence is most well developed.
27 Aug 2013
TL;DR: A novel technique is developed that leverages a small amount of scratch capacity on links to apply updates in a provably congestion-free manner, without making any assumptions about the order and timing of updates at individual switches.
Abstract: We present SWAN, a system that boosts the utilization of inter-datacenter networks by centrally controlling when and how much traffic each service sends and frequently re-configuring the network's data plane to match current traffic demand. But done simplistically, these re-configurations can also cause severe, transient congestion because different switches may apply updates at different times. We develop a novel technique that leverages a small amount of scratch capacity on links to apply updates in a provably congestion-free manner, without making any assumptions about the order and timing of updates at individual switches. Further, to scale to large networks in the face of limited forwarding table capacity, SWAN greedily selects a small set of entries that can best satisfy current demand. It updates this set without disrupting traffic by leveraging a small amount of scratch capacity in forwarding tables. Experiments using a testbed prototype and data-driven simulations of two production networks show that SWAN carries 60% more traffic than the current practice.
TL;DR: 3D interdigitated microbattery architectures fabricated by printing concentrated lithium oxide-based inks exhibit high areal energy and power densities, which may find potential application in autonomously powered microdevices.
Abstract: 3D interdigitated microbattery architectures (3D-IMA) are fabricated by printing concentrated lithium oxide-based inks. The microbatteries are composed of interdigitated, high-aspect ratio cathode and anode structures. Our 3D-IMA, which exhibit high areal energy and power densities, may find potential application in autonomously powered microdevices.
TL;DR: The ability of these ultrathin, mechanically compliant, biocompatible devices to afford minimally invasive operation in the soft tissues of the mammalian brain foreshadow applications in other organ systems, with potential for broad utility in biomedical science and engineering.
Abstract: Successful integration of advanced semiconductor devices with biological systems will accelerate basic scientific discoveries and their translation into clinical technologies. In neuroscience generally, and in optogenetics in particular, the ability to insert light sources, detectors, sensors, and other components into precise locations of the deep brain yields versatile and important capabilities. Here, we introduce an injectable class of cellular-scale optoelectronics that offers such features, with examples of unmatched operational modes in optogenetics, including completely wireless and programmed complex behavioral control over freely moving animals. The ability of these ultrathin, mechanically compliant, biocompatible devices to afford minimally invasive operation in the soft tissues of the mammalian brain foreshadow applications in other organ systems, with potential for broad utility in biomedical science and engineering.
TL;DR: This work introduces a large area, flexible piezoelectric material that consists of sheets of electrospun fibres of the polymer poly[(vinylidenefluoride-co-trifluoroethylene] in order to enable ultra-high sensitivity for measuring pressure, even at exceptionally small values (0.1 Pa).
Abstract: Multifunctional capability, flexible design, rugged lightweight construction and self-powered operation are desired attributes for electronics that directly interface with the human body or with advanced robotic systems. For these applications, piezoelectric materials, in forms that offer the ability to bend and stretch, are attractive for pressure/force sensors and mechanical energy harvesters. Here, we introduce a large area, flexible piezoelectric material that consists of sheets of electrospun fibres of the polymer poly[(vinylidenefluoride-co-trifluoroethylene]. The flow and mechanical conditions associated with the spinning process yield free-standing, three-dimensional architectures of aligned arrangements of such fibres, in which the polymer chains adopt strongly preferential orientations. The resulting material offers exceptional piezoelectric characteristics, to enable ultra-high sensitivity for measuring pressure, even at exceptionally small values (0.1 Pa). Quantitative analysis provides detailed insights into the pressure sensing mechanisms, and establishes engineering design rules. Potential applications range from self-powered micro-mechanical elements, to self-balancing robots and sensitive impact detectors.
TL;DR: An ultrathin, compliant skin-like sensor/actuator technology that can pliably laminate onto the epidermis to provide continuous, accurate thermal characterizations that are unavailable with other methods are introduced.
Abstract: Precision thermometry of the skin can, together with other measurements, provide clinically relevant information about cardiovascular health, cognitive state, malignancy and many other important aspects of human physiology. Here, we introduce an ultrathin, compliant skin-like sensor/actuator technology that can pliably laminate onto the epidermis to provide continuous, accurate thermal characterizations that are unavailable with other methods. Examples include non-invasive spatial mapping of skin temperature with millikelvin precision, and simultaneous quantitative assessment of tissue thermal conductivity. Such devices can also be implemented in ways that reveal the time-dynamic influence of blood flow and perfusion on these properties. Experimental and theoretical studies establish the underlying principles of operation, and define engineering guidelines for device design. Evaluation of subtle variations in skin temperature associated with mental activity, physical stimulation and vasoconstriction/dilation along with accurate determination of skin hydration through measurements of thermal conductivity represent some important operational examples.
TL;DR: This paper proposed to frame sentence-based image annotation as the task of ranking a given pool of captions and showed that the importance of training on multiple captions per image, and of capturing syntactic (word order-based) and semantic features of these captions, is emphasized.
Abstract: The ability to associate images with natural language sentences that describe what is depicted in them is a hallmark of image understanding, and a prerequisite for applications such as sentence-based image search. In analogy to image search, we propose to frame sentence-based image annotation as the task of ranking a given pool of captions. We introduce a new benchmark collection for sentence-based image description and search, consisting of 8,000 images that are each paired with five different captions which provide clear descriptions of the salient entities and events. We introduce a number of systems that perform quite well on this task, even though they are only based on features that can be obtained with minimal supervision. Our results clearly indicate the importance of training on multiple captions per image, and of capturing syntactic (word order-based) and semantic features of these captions. We also perform an in-depth comparison of human and automatic evaluation metrics for this task, and propose strategies for collecting human judgments cheaply and on a very large scale, allowing us to augment our collection with additional relevance judgments of which captions describe which image. Our analysis shows that metrics that consider the ranked list of results for each query image or sentence are significantly more robust than metrics that are based on a single response per query. Moreover, our study suggests that the evaluation of ranking-based image description systems may be fully automated.
01 Jan 2013
TL;DR: This work develops a broadcast-based algorithm, termed the subgradient-push, which steers every node to an optimal value under a standard assumption of subgradient boundedness, which converges at a rate of O (ln t/√t), where the constant depends on the initial values at the nodes, the sub gradient norms, and, more interestingly, on both the consensus speed and the imbalances of influence among the nodes.
Abstract: We consider distributed optimization by a collection of nodes, each having access to its own convex function, whose collective goal is to minimize the sum of the functions. The communications between nodes are described by a time-varying sequence of directed graphs, which is uniformly strongly connected. For such communications, assuming that every node knows its out-degree, we develop a broadcast-based algorithm, termed the subgradient-push, which steers every node to an optimal value under a standard assumption of subgradient boundedness. The subgradient-push requires no knowledge of either the number of agents or the graph sequence to implement. Our analysis shows that the subgradient-push algorithm converges at a rate of O (ln t/√t), where the constant depends on the initial values at the nodes, the subgradient norms, and, more interestingly, on both the consensus speed and the imbalances of influence among the nodes.
French Institute of Health and Medical Research1, University of Bordeaux2, King's College London3, University of Valencia4, World Health Organization5, University of Illinois at Urbana–Champaign6, McGill University7, University of Bedfordshire8, Erasmus University Rotterdam9, University of Rennes10, National Institutes of Health11, Columbia University12, Dalhousie University13, Autonomous University of Madrid14, University of Foggia15, Pan American Health Organization16
TL;DR: There is agreement on the usefulness of defining frailty in clinical settings as well as on its main dimensions, however, additional research is needed before an operative definition of frailty can be established.
Abstract: BACKGROUND: There is no consensus regarding the definition of frailty for clinical uses. METHODS: A modified Delphi process was used to attempt to achieve consensus definition. Experts were selected from different fields and organized into five Focus Groups. A questionnaire was developed and sent to experts in the area of frailty. Responses and comments were analyzed using a pre-established strategy. Statements with an agreement more than or equal to 80% were accepted. RESULTS: Overall, 44% of the statements regarding the concept of frailty and 18% of the statements regarding diagnostic criteria were accepted. There was consensus on the value of screening for frailty and about the identification of six domains of frailty for inclusion in a clinical definition, but no agreement was reached concerning a specific set of clinical/laboratory biomarkers useful for diagnosis. CONCLUSIONS: There is agreement on the usefulness of defining frailty in clinical settings as well as on its main dimensions. However, additional research is needed before an operative definition of frailty can be established.
TL;DR: High throughput microbial 16S ribosomal RNA gene sequencing indicated that diversity, richness and composition of howler GI microbiomes varied with host habitat in relation to diet, and a reduction in the number of genes related to butyrate production and hydrogen metabolism in the microbiomes of howlers occupying suboptimal habitats may impact host health.
Abstract: The gastrointestinal (GI) microbiome contributes significantly to host nutrition and health. However, relationships involving GI microbes, their hosts and host macrohabitats remain to be established. Here, we define clear patterns of variation in the GI microbiomes of six groups of Mexican black howler monkeys (Alouatta pigra) occupying a gradation of habitats including a continuous evergreen rainforest, an evergreen rainforest fragment, a continuous semi-deciduous forest and captivity. High throughput microbial 16S ribosomal RNA gene sequencing indicated that diversity, richness and composition of howler GI microbiomes varied with host habitat in relation to diet. Howlers occupying suboptimal habitats consumed less diverse diets and correspondingly had less diverse gut microbiomes. Quantitative real-time PCR also revealed a reduction in the number of genes related to butyrate production and hydrogen metabolism in the microbiomes of howlers occupying suboptimal habitats, which may impact host health.
TL;DR: The devices combine elastomeric compound optical elements with deformable arrays of thin silicon photodetectors into integrated sheets that can be elastically transformed from the planar geometries in which they are fabricated to hemispherical shapes for integration into apposition cameras.
Abstract: In arthropods, evolution has created a remarkably sophisticated class of imaging systems, with a wide-angle field of view, low aberrations, high acuity to motion and an infinite depth of field. A challenge in building digital cameras with the hemispherical, compound apposition layouts of arthropod eyes is that essential design requirements cannot be met with existing planar sensor technologies or conventional optics. Here we present materials, mechanics and integration schemes that afford scalable pathways to working, arthropod-inspired cameras with nearly full hemispherical shapes (about 160 degrees). Their surfaces are densely populated by imaging elements (artificial ommatidia), which are comparable in number (180) to those of the eyes of fire ants (Solenopsis fugax) and bark beetles (Hylastes nigrinus). The devices combine elastomeric compound optical elements with deformable arrays of thin silicon photodetectors into integrated sheets that can be elastically transformed from the planar geometries in which they are fabricated to hemispherical shapes for integration into apposition cameras. Our imaging results and quantitative ray-tracing-based simulations illustrate key features of operation. These general strategies seem to be applicable to other compound eye devices, such as those inspired by moths and lacewings (refracting superposition eyes), lobster and shrimp (reflecting superposition eyes), and houseflies (neural superposition eyes).
Proceedings Article•
02 Apr 2013TL;DR: VeriFlow as discussed by the authors is a layer between a software-defined networking controller and network devices that checks for network-wide invariant violations dynamically as each forwarding rule is inserted, modified or deleted.
Abstract: Networks are complex and prone to bugs. Existing tools that check network configuration files and the data-plane state operate offline at timescales of seconds to hours, and cannot detect or prevent bugs as they arise.
Is it possible to check network-wide invariants in real time, as the network state evolves? The key challenge here is to achieve extremely low latency during the checks so that network performance is not affected. In this paper, we present a design, VeriFlow, which achieves this goal. VeriFlow is a layer between a software-defined networking controller and network devices that checks for network-wide invariant violations dynamically as each forwarding rule is inserted, modified or deleted. VeriFlow supports analysis over multiple header fields, and an API for checking custom invariants. Based on a prototype implementation integrated with the NOX OpenFlow controller, and driven by a Mininet OpenFlow network and Route Views trace data, we find that VeriFlow can perform rigorous checking within hundreds of microseconds per rule insertion or deletion.
University of Alberta1, Peking University2, Chinese Academy of Sciences3, Macquarie University4, Los Alamos National Laboratory5, Northwestern University6, Radboud University Nijmegen7, McMaster University8, Nanjing University9, Xinjiang University10, University of Warwick11, University of Oxford12, University of Cambridge13, Technion – Israel Institute of Technology14, Academia Sinica15, University of Bonn16, Max Planck Society17, University of Amsterdam18, University of Illinois at Urbana–Champaign19
TL;DR: In this paper, the authors present the current best physical understanding of common envelope evolution (CEE) and highlight areas of consensus and disagreement, and stress ideas which should point the way forward for progress in this important but long-standing and largely unconquered problem.
Abstract: This work aims to present our current best physical understanding of common-envelope evolution (CEE). We highlight areas of consensus and disagreement, and stress ideas which should point the way forward for progress in this important but long-standing and largely unconquered problem. Unusually for CEE-related work, we mostly try to avoid relying on results from population synthesis or observations, in order to avoid potentially being misled by previous misunderstandings. As far as possible we debate all the relevant issues starting from physics alone, all the way from the evolution of the binary system immediately before CEE begins to the processes which might occur just after the ejection of the envelope. In particular, we include extensive discussion about the energy sources and sinks operating in CEE, and hence examine the foundations of the standard energy formalism. Special attention is also given to comparing the results of hydrodynamic simulations from different groups and to discussing the potential effect of initial conditions on the differences in the outcomes. We compare current numerical techniques for the problem of CEE and also whether more appropriate tools could and should be produced (including new formulations of computational hydrodynamics, and attempts to include 3D processes within 1D codes). Finally we explore new ways to link CEE with observations. We compare previous simulations of CEE to the recent outburst from V1309 Sco, and discuss to what extent post-common-envelope binaries and nebulae can provide information, e.g. from binary eccentricities, which is not currently being fully exploited.
TL;DR: Recent progress in the design and synthetic strategies for ORR catalysts including controlling the shape and size of Pt and its bimetallic alloys, and controlling the surface composition and structure of core-shell, monolayer, and hollow porous structures are reviewed.
Abstract: An efficient oxygen reduction reaction (ORR) offers the potential for clean energy generation in low-temperature, proton-exchange membrane fuel cells running on hydrogen fuel and air. In the past several years, researchers have developed high-performance electrocatalysts for the ORR to address the obstacles of high cost of the Pt catalyst per kilowatt of output power and of declining catalyst activity over time. Current efforts are focused on new catalyst structures that add a secondary metal to change the d-band center and the surface atomic arrangement of the catalyst, altering the chemisorption of those oxygencontaining species that have the largest impact on the ORR kinetics and improving the catalyst activity and cost effectiveness.This Account reviews recent progress in the design of Pt-based ORR electrocatalysts, including improved understanding of the reaction mechanisms and the development of synthetic methods for producing catalysts with high activity and stability. Researchers have made several...
Delft University of Technology1, UNESCO-IHE Institute for Water Education2, Vienna University of Technology3, University of Saskatchewan4, University of Illinois at Urbana–Champaign5, Swedish Meteorological and Hydrological Institute6, National Center for Atmospheric Research7, Karlsruhe Institute of Technology8, University of Bristol9, Russian Academy of Sciences10, University of Arizona11, Rhodes University12, University of Bologna13, University of Aberdeen14, Agrocampus Ouest15
TL;DR: The Prediction in Ungauged Basins (PUB) initiative of the International Association of Hydrological Sciences (IAHS) launched in 2003 and concluded by the PUB Symposium 2012 held in Delft (23-25 October 2012), set out to shift the scientific culture of hydrology towards improved scientific understanding of hydrological processes, as well as associated uncertainties and the development of models with increasing realism and predictive power as discussed by the authors.
Abstract: The Prediction in Ungauged Basins (PUB) initiative of the International Association of Hydrological Sciences (IAHS), launched in 2003 and concluded by the PUB Symposium 2012 held in Delft (23–25 October 2012), set out to shift the scientific culture of hydrology towards improved scientific understanding of hydrological processes, as well as associated uncertainties and the development of models with increasing realism and predictive power. This paper reviews the work that has been done under the six science themes of the PUB Decade and outlines the challenges ahead for the hydrological sciences community.Editor D. KoutsoyiannisCitation Hrachowitz, M., Savenije, H.H.G., Bloschl, G., McDonnell, J.J., Sivapalan, M., Pomeroy, J.W., Arheimer, B., Blume, T., Clark, M.P., Ehret, U., Fenicia, F., Freer, J.E., Gelfan, A., Gupta, H.V., Hughes, D.A., Hut, R.W., Montanari, A., Pande, S., Tetzlaff, D., Troch, P.A., Uhlenbrook, S., Wagener, T., Winsemius, H.C., Woods, R.A., Zehe, E., and Cudennec, C., 2013. A d...
TL;DR: Using historic data sets, the degree to which global change over 120 years disrupted plant-pollinator interactions in a temperate forest understory community in Illinois, USA is quantified and it is suggested that networks will be less resilient to future changes.
Abstract: Using historic data sets, we quantified the degree to which global change over 120 years disrupted plant-pollinator interactions in a temperate forest understory community in Illinois, USA. We found degradation of interaction network structure and function and extirpation of 50% of bee species. Network changes can be attributed to shifts in forb and bee phenologies resulting in temporal mismatches, nonrandom species extinctions, and loss of spatial co-occurrences between extant species in modified landscapes. Quantity and quality of pollination services have declined through time. The historic network showed flexibility in response to disturbance; however, our data suggest that networks will be less resilient to future changes.
TL;DR: This tutorial review provides examples of how the chemical and physical effects of high intensity ultrasound can be exploited for the preparation or modification of a wide range of nanostructured materials.
Abstract: High intensity ultrasound can be used for the production of novel materials and provides an unusual route to known materials without bulk high temperatures, high pressures, or long reaction times. Several phenomena are responsible for sonochemistry and specifically the production or modification of nanomaterials during ultrasonic irradiation. The most notable effects are consequences of acoustic cavitation (the formation, growth, and implosive collapse of bubbles), and can be categorized as primary sonochemistry (gas-phase chemistry occurring inside collapsing bubbles), secondary sonochemistry (solution-phase chemistry occurring outside the bubbles), and physical modifications (caused by high-speed jets or shock waves derived from bubble collapse). This tutorial review provides examples of how the chemical and physical effects of high intensity ultrasound can be exploited for the preparation or modification of a wide range of nanostructured materials.
TL;DR: The present review is a transition metal-catalyzed synthesis of aromatic monocyclic heterocycles, aiming at achieving greater levels of molecular complexity and better functional group compatibilities in a convergent and atom economical fashions from readily accessible starting materials and under mild reaction conditions.
Abstract: Heterocycles constitute the largest and the most diverse family of organic compounds Among them, aromatic heterocycles represent structural motifs found in a great number of biologically active natural and synthetic compounds, drugs, and agrochemicals Moreover, aromatic heterocycles are widely used for synthesis of dyes and polymeric materials of high value 1 There are numerous reports on employment of aromatic heterocycles as intermediates in organic synthesis 2
Although, a variety of highly efficient methodologies for synthesis of aromatic heterocycles and their derivatives have been reported in the past, the development of novel methodologies is in cuntinious demand Particlularly, development of new synthetic approaches toward heterocycles, aiming at achieving greater levels of molecular complexity and better functional group compatibilities in a convergent and atom economical fashions from readily accessible starting materials and under mild reaction conditions, is one of a major research endeavor in modern synthetic organic chemistry Transition metal-catalyzed transformations, which often help to meet the above criteria, are among the most attractive synthetic tools
Several excellent reviews dealing with transition metal-catalyzed synthesis of heterocyclic compounds have been published in literature during recent years Many of them highlighted the use of a particular transition metal, such as gold,3 silver,4 palladium,5 copper,6 cobalt,7 ruthenium,8 iron,9 mercury,10 rare-earth metals,11 and others Another array of reviews described the use of a specific kind of transformation, for instance, intramolecular nucleophilic attack of heteroatom at multiple C–C bonds,12 Sonogashira reaction,13 cycloaddition reactions,14 cycloisomerization reactions,15 C–H bond activation processes,16 metathesis reactions,17 etc Reviews devoted to an application of a particular type of starting materials have also been published Thus, for example, applications of isocyanides,18 diazocompounds,19 or azides20 have been discussed In addition, a significant attention was given to transition metal-catalyzed multicomponent syntheses of heterocycles21 Finally, syntheses of heterocycles featuring formation of intermediates, such as nitrenes,22 vinylidenes,23 carbenes, and carbenoids24 have also been reviewed
The main focus of the present review is a transition metal-catalyzed synthesis of aromatic monocyclic heterocycles The organization of the review is rather classical and is based on a heterocycle, categorized in the following order: (a) ring size of heterocycle, (b) number of heteroatoms, (c) type of heterocycle, and (d) a class of transformation involved A brief mechanistic discussion is given to provide information about a possible reaction pathway when necessary The review mostly discusses recent literature, starting from 200425 until the end of 2011, however, some earlier parent transformations are discussed when needed