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Showing papers by "University of Notre Dame published in 2008"


Journal ArticleDOI
20 Mar 2008-Nature
TL;DR: Some of the science and technology being developed to improve the disinfection and decontamination of water, as well as efforts to increase water supplies through the safe re-use of wastewater and efficient desalination of sea and brackish water are highlighted.
Abstract: One of the most pervasive problems afflicting people throughout the world is inadequate access to clean water and sanitation. Problems with water are expected to grow worse in the coming decades, with water scarcity occurring globally, even in regions currently considered water-rich. Addressing these problems calls out for a tremendous amount of research to be conducted to identify robust new methods of purifying water at lower cost and with less energy, while at the same time minimizing the use of chemicals and impact on the environment. Here we highlight some of the science and technology being developed to improve the disinfection and decontamination of water, as well as efforts to increase water supplies through the safe re-use of wastewater and efficient desalination of sea and brackish water.

6,967 citations


Journal ArticleDOI
10 Mar 2008-Nature
TL;DR: In this article, the authors study the trajectory of 100,000 anonymized mobile phone users whose position is tracked for a six-month period and find that the individual travel patterns collapse into a single spatial probability distribution, indicating that humans follow simple reproducible patterns.
Abstract: The mapping of large-scale human movements is important for urban planning, traffic forecasting and epidemic prevention. Work in animals had suggested that their foraging might be explained in terms of a random walk, a mathematical rendition of a series of random steps, or a Levy flight, a random walk punctuated by occasional larger steps. The role of Levy statistics in animal behaviour is much debated — as explained in an accompanying News Feature — but the idea of extending it to human behaviour was boosted by a report in 2006 of Levy flight-like patterns in human movement tracked via dollar bills. A new human study, based on tracking the trajectory of 100,000 cell-phone users for six months, reveals behaviour close to a Levy pattern, but deviating from it as individual trajectories show a high degree of temporal and spatial regularity: work and other commitments mean we are not as free to roam as a foraging animal. But by correcting the data to accommodate individual variation, simple and predictable patterns in human travel begin to emerge. The cover photo (by Cesar Hidalgo) captures human mobility in New York's Grand Central Station. This study used a sample of 100,000 mobile phone users whose trajectory was tracked for six months to study human mobility patterns. Displacements across all users suggest behaviour close to the Levy-flight-like pattern observed previously based on the motion of marked dollar bills, but with a cutoff in the distribution. The origin of the Levy patterns observed in the aggregate data appears to be population heterogeneity and not Levy patterns at the level of the individual. Despite their importance for urban planning1, traffic forecasting2 and the spread of biological3,4,5 and mobile viruses6, our understanding of the basic laws governing human motion remains limited owing to the lack of tools to monitor the time-resolved location of individuals. Here we study the trajectory of 100,000 anonymized mobile phone users whose position is tracked for a six-month period. We find that, in contrast with the random trajectories predicted by the prevailing Levy flight and random walk models7, human trajectories show a high degree of temporal and spatial regularity, each individual being characterized by a time-independent characteristic travel distance and a significant probability to return to a few highly frequented locations. After correcting for differences in travel distances and the inherent anisotropy of each trajectory, the individual travel patterns collapse into a single spatial probability distribution, indicating that, despite the diversity of their travel history, humans follow simple reproducible patterns. This inherent similarity in travel patterns could impact all phenomena driven by human mobility, from epidemic prevention to emergency response, urban planning and agent-based modelling.

5,514 citations


Journal ArticleDOI
TL;DR: The Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) at CERN as mentioned in this paper was designed to study proton-proton (and lead-lead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 10(34)cm(-2)s(-1)
Abstract: The Compact Muon Solenoid (CMS) detector is described. The detector operates at the Large Hadron Collider (LHC) at CERN. It was conceived to study proton-proton (and lead-lead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 10(34)cm(-2)s(-1) (10(27)cm(-2)s(-1)). At the core of the CMS detector sits a high-magnetic-field and large-bore superconducting solenoid surrounding an all-silicon pixel and strip tracker, a lead-tungstate scintillating-crystals electromagnetic calorimeter, and a brass-scintillator sampling hadron calorimeter. The iron yoke of the flux-return is instrumented with four stations of muon detectors covering most of the 4 pi solid angle. Forward sampling calorimeters extend the pseudo-rapidity coverage to high values (vertical bar eta vertical bar <= 5) assuring very good hermeticity. The overall dimensions of the CMS detector are a length of 21.6 m, a diameter of 14.6 m and a total weight of 12500 t.

5,193 citations


Journal ArticleDOI
TL;DR: In this paper, three major ways to utilize semiconductor dots in solar cell include (i) metal−semiconductor or Schottky junction photovoltaic cell, (ii) polymer−smiconductor hybrid solar cell, and (iii) quantum dot sensitized solar cell.
Abstract: The emergence of semiconductor nanocrystals as the building blocks of nanotechnology has opened up new ways to utilize them in next generation solar cells. This paper focuses on the recent developments in the utilization of semiconductor quantum dots for light energy conversion. Three major ways to utilize semiconductor dots in solar cell include (i) metal−semiconductor or Schottky junction photovoltaic cell (ii) polymer−semiconductor hybrid solar cell, and (iii) quantum dot sensitized solar cell. Modulation of band energies through size control offers new ways to control photoresponse and photoconversion efficiency of the solar cell. Various strategies to maximize photoinduced charge separation and electron transfer processes for improving the overall efficiency of light energy conversion are discussed. Capture and transport of charge carriers within the semiconductor nanocrystal network to achieve efficient charge separation at the electrode surface remains a major challenge. Directing the future resear...

2,434 citations


Journal ArticleDOI
03 Jul 2008-ACS Nano
TL;DR: The photocatalytic methodology not only provides an on-demand UV-assisted reduction technique but also opens up new ways to obtain photoactive graphene-semiconductor composites.
Abstract: Graphene oxide suspended in ethanol undergoes reduction as it accepts electrons from UV-irradiated TiO2 suspensions. The reduction is accompanied by changes in the absorption of the graphene oxide, as the color of the suspension shifts from brown to black. The direct interaction between TiO2 particles and graphene sheets hinders the collapse of exfoliated sheets of graphene. Solid films cast on a borosilicate glass gap separated by gold-sputtered terminations show an order of magnitude decrease in lateral resistance following reduction with the TiO2 photocatalyst. The photocatalytic methodology not only provides an on-demand UV-assisted reduction technique but also opens up new ways to obtain photoactive graphene-semiconductor composites.

2,397 citations


Journal ArticleDOI
TL;DR: Two major findings are highlighted: ability to tune the photoelectrochemical response and photoconversion efficiency via size control of CdSe quantum dots and improvement in the photoconversions efficiency by facilitating the charge transport through TiO2 nanotube architecture.
Abstract: Different-sized CdSe quantum dots have been assembled on TiO2 films composed of particle and nanotube morphologies using a bifunctional linker molecule. Upon band-gap excitation, CdSe quantum dots inject electrons into TiO2 nanoparticles and nanotubes, thus enabling the generation of photocurrent in a photoelectrochemical solar cell. The results presented in this study highlight two major findings: (i) ability to tune the photoelectrochemical response and photoconversion efficiency via size control of CdSe quantum dots and (ii) improvement in the photoconversion efficiency by facilitating the charge transport through TiO2 nanotube architecture. The maximum IPCE (photon-to-charge carrier generation efficiency) obtained with 3 nm diameter CdSe nanoparticles was 35% for particulate TiO2 and 45% for tubular TiO2 morphology. The maximum IPCE observed at the excitonic band increases with decreasing particle size, whereas the shift in the conduction band to more negative potentials increases the driving force and favors fast electron injection. The maximum power-conversion efficiency

1,608 citations


Journal ArticleDOI
13 Mar 2008-Nature
TL;DR: It is demonstrated that excess nitrate in streams elicits a disproportionate increase in the fraction of nitrate that is exported to receiving waters and reduces the relative role of small versus large streams as nitrate sinks.
Abstract: About a quarter of the nitrogen added to the biosphere is exported from rivers to the ocean or inland basins, indicating substantial sinks for nitrogen must exist in the landscape. Data from nitrogen stable isotope tracer experiments across 72 streams suggests that the total uptake of nitrate is related to ecosystem photosynthesis, and that denitrification is related to ecosystem respiration. A stream network model demonstrates that excess nitrate in streams elicits a disproportionate increase in the fraction of nitrate that is exported to receiving waters and reduces the relative role of small versus large streams as nitrate sinks. Anthropogenic addition of bioavailable nitrogen to the biosphere is increasing1,2 and terrestrial ecosystems are becoming increasingly nitrogen-saturated3, causing more bioavailable nitrogen to enter groundwater and surface waters4,5,6. Large-scale nitrogen budgets show that an average of about 20–25 per cent of the nitrogen added to the biosphere is exported from rivers to the ocean or inland basins7,8, indicating that substantial sinks for nitrogen must exist in the landscape9. Streams and rivers may themselves be important sinks for bioavailable nitrogen owing to their hydrological connections with terrestrial systems, high rates of biological activity, and streambed sediment environments that favour microbial denitrification6,10,11. Here we present data from nitrogen stable isotope tracer experiments across 72 streams and 8 regions representing several biomes. We show that total biotic uptake and denitrification of nitrate increase with stream nitrate concentration, but that the efficiency of biotic uptake and denitrification declines as concentration increases, reducing the proportion of in-stream nitrate that is removed from transport. Our data suggest that the total uptake of nitrate is related to ecosystem photosynthesis and that denitrification is related to ecosystem respiration. In addition, we use a stream network model to demonstrate that excess nitrate in streams elicits a disproportionate increase in the fraction of nitrate that is exported to receiving waters and reduces the relative role of small versus large streams as nitrate sinks.

1,193 citations


Journal ArticleDOI
TL;DR: The stages of invasion known as the "invasion pathway" are used to identify 5 nonexclusive consequences of climate change for invasive species and the need for enhanced environmental monitoring and expanded coordination among entities involved in invasive-species management is emphasized.
Abstract: Scientific and societal unknowns make it difficult to predict how global environmental changes such as climate change and biological invasions will affect ecological systems. In the long term, these changes may have interacting effects and compound the uncertainty associated with each individual driver. Nonetheless, invasive species are likely to respond in ways that should be qualitatively predictable, and some of these responses will be distinct from those of native counterparts. We used the stages of invasion known as the "invasion pathway" to identify 5 nonexclusive consequences of climate change for invasive species: (1) altered transport and introduction mechanisms, (2) establishment of new invasive species, (3) altered impact of existing invasive species, (4) altered distribution of existing invasive species, and (5) altered effectiveness of control strategies. We then used these consequences to identify testable hypotheses about the responses of invasive species to climate change and provide suggestions for invasive-species management plans. The 5 consequences also emphasize the need for enhanced environmental monitoring and expanded coordination among entities involved in invasive-species management.

1,130 citations


Journal ArticleDOI
TL;DR: This survey covers the historical development and current state of the art in image understanding for iris biometrics and suggests a short list of recommended readings for someone new to the field to quickly grasp the big picture of irisBiometrics.

933 citations


Journal ArticleDOI
TL;DR: In this paper, a solution-based approach of chemical reduction of AuCl4- ions in graphene suspensions is explored, where gold particles anchored on octadecylamine functionalized graphene are readily suspendable in THF medium.
Abstract: Renewed interest in graphene architectures has opened up new avenues to utilize them in electronic and optoelectronic applications. The desire to design graphene−metal nanohybrid assemblies has led us to explore a solution-based approach of chemical reduction of AuCl4- ions in graphene suspensions. The gold particles anchored on octadecylamine functionalized graphene are readily suspendable in THF medium. The dependence of particle stability on the graphene concentration and SEM analysis indicate that the gold nanoparticles are well dispersed on graphene sheets. Transient absorption spectroscopy measurements suggest that the ultrafast disappearance of plasmon absorption and its recovery are unaffected by the presence of graphene.

886 citations


Journal ArticleDOI
TL;DR: In this paper, the recent developments and trends in combustion science towards the synthesis of nanomaterials are discussed, and different modifications made to conventional combustion approaches for preparation of nano-materials are critically analyzed.
Abstract: The recent developments and trends in combustion science towards the synthesis of nanomaterials are discussed. Different modifications made to conventional combustion approaches for preparation of nanomaterials are critically analyzed. Special attention is paid to various applications of combustion synthesized nanosized products.

Journal ArticleDOI
21 Mar 2008-Science
TL;DR: This work has established that variations in surface and near-surface atomic structure as a function of size in this smallest of size regimes may make a difference in important geochemical and biogeochemical reactions and kinetics in minerals.
Abstract: Minerals are more complex than previously thought because of the discovery that their chemical properties vary as a function of particle size when smaller, in at least one dimension, than a few nanometers, to perhaps as much as several tens of nanometers. These variations are most likely due, at least in part, to differences in surface and near-surface atomic structure, as well as crystal shape and surface topography as a function of size in this smallest of size regimes. It has now been established that these variations may make a difference in important geochemical and biogeochemical reactions and kinetics. This recognition is broadening and enriching our view of how minerals influence the hydrosphere, pedosphere, biosphere, and atmosphere.

Journal ArticleDOI
01 Jun 2008-Traffic
TL;DR: Exosomes isolated from cells infected with various intracellular pathogens have been shown to contain microbial components and can promote antigen presentation and macrophage activation, suggesting that exosomes may function in immune surveillance.
Abstract: The number of studies concerning bioactive vesicles has significantly increased in recent years with much of this increase stemming from work on exosomes. This class of bioactive vesicles is formed through the fusion of multivesicular bodies (MVBs) with the plasma membrane and release of intraluminal vesicles (ILVs) as exosomes. Originally observed as a mechanism to remove transferrin receptor during reticulocyte maturation (1), more recent studies have focused on the role of exosomes in antigen presentation (reviewed in 2). The presence of antigens on exosomes released from tumor cells and the ability of these exosomes to stimulate anti-tumor responses in vitro and in vivo suggest that their use may hold therapeutic promise for cancer patients. An area of very recent interest has been on exosomes role in the spread of pathogens as well as their potential function in promoting or regulating an immune response upon infection. Studies have shown that exosomes may function in the cell-to-cell spread of HIV (3,4), although this may simply reflect analogous biogenesis/trafficking of exosome and envelope proteins (5). Exosomes have also been successfully used as vaccines against various pathogens. Finally, studies have suggested that exosomes released from cells infected with intracellular pathogens such as Mycobacterium tuberculosis (M. tb) contain microbial components and that these exosomes have immune modulatory activity. In this review, we give a general summary of MVBs and exosomes but focus primarily on their diverse functions as well as their potential usefulness as vaccines and disease biomarkers.

Journal ArticleDOI
TL;DR: The mean collective behavior at large scales is studied and it is shown that the interevent time of consecutive calls is heavy-tailed, which has implications for dynamics of spreading phenomena in social networks.
Abstract: Novel aspects of human dynamics and social interactions are investigated by means of mobile phone data. Using extensive phone records resolved in both time and space, we study the mean collective behavior at large scales and focus on the occurrence of anomalous events. We discuss how these spatiotemporal anomalies can be described using standard percolation theory tools. We also investigate patterns of calling activity at the individual level and show that the interevent time of consecutive calls is heavy-tailed. This finding, which has implications for dynamics of spreading phenomena in social networks, agrees with results previously reported on other human activities.

Journal ArticleDOI
TL;DR: A conservative least-squares polynomial reconstruction operator is applied to the discontinuous Galerkin method, which yields space–time polynomials for the vector of conserved variables and for the physical fluxes and source terms that can be used in a natural way to construct very efficient fully-discrete and quadrature-free one-step schemes.

Journal ArticleDOI
TL;DR: Early detection and in-depth understanding of invasive species and infectious diseases will require an integrated network of research platforms and information exchange to identify hotspots of invasion or disease emergence, which can facilitate a full understanding of the resulting effects on ecosystems and society as mentioned in this paper.
Abstract: Invasive species, disease vectors, and pathogens affect biodiversity, ecosystem function and services, and human health. Climate change, land use, and transport vectors interact in complex ways to determine the spread of native and non-native invasive species, pathogens, and their effects on ecosystem dynamics. Early detection and in-depth understanding of invasive species and infectious diseases will require an integrated network of research platforms and information exchange to identify hotspots of invasion or disease emergence. Partnerships with state and federal agencies that monitor the spread and impacts of invasive species and pathogens will be critical in developing a national data and research network that can facilitate a full understanding of the resulting effects on ecosystems and society. Citizen science can also play a role; individuals can report new invasions, record phenological changes associated with invasions or disease outbreaks, and can participate in efforts such as the Breeding Bir...

Journal ArticleDOI
TL;DR: This article found that 60% of the propensity to vote is passed onto the other member of the household, suggesting a mechanism by which civic participation norms are adopted and couples grow more similar over time.
Abstract: Members of the same household share similar voting behaviors on average, but how much of this correlation can be attributed to the behavior of the other person in the household? Disentangling and isolating the unique effects of peer behavior, selection processes, and congruent interests is a challenge for all studies of interpersonal influence. This study proposes and utilizes a carefully designed placebo-controlled experimental protocol to overcome this identification problem. During a face-to-face canvassing experiment targeting households with two registered voters, residents who answered the door were exposed to either a Get Out the Vote message (treatment) or a recycling pitch (placebo). The turnout of the person in the household not answering the door allows for contagion to be measured. Both experiments find that 60% of the propensity to vote is passed onto the other member of the household. This finding suggests a mechanism by which civic participation norms are adopted and couples grow more similar over time.

Journal ArticleDOI
TL;DR: In this article, a power-law distribution of on-and off-times observed in colloidal semiconductor quantum dots, nanorods, nanowires and some organic dyes is discussed.
Abstract: Virtually all known fluorophores exhibit mysterious episodes of emission intermittency. A remarkable feature of the phenomenon is a power-law distribution of on- and off-times observed in colloidal semiconductor quantum dots, nanorods, nanowires and some organic dyes. For nanoparticles, the resulting power law extends over an extraordinarily wide dynamic range: nine orders of magnitude in probability density and five to six orders of magnitude in time. Exponents hover about the ubiquitous value of -3/2. Dark states routinely last for tens of seconds—practically forever on quantum mechanical timescales. Despite such infinite states of darkness, the dots miraculously recover and start emitting again. Although the underlying mechanism responsible for this phenomenon remains a mystery and many questions persist, we argue that substantial theoretical progress has been made.

Journal ArticleDOI
Joshua A. Frieman1, Joshua A. Frieman2, Bruce A. Bassett3, Andrew C. Becker4, Changsu Choi5, D. Cinabro6, F. DeJongh2, Darren L. DePoy7, Ben Dilday1, Mamoru Doi8, Peter M. Garnavich9, Craig J. Hogan4, Jon A. Holtzman10, Myungshin Im5, Saurabh Jha11, Richard Kessler1, Kohki Konishi8, Hubert Lampeitl12, John Marriner2, Jennifer L. Marshall7, D. McGinnis2, G. Miknaitis2, Robert C. Nichol13, J. L. Prieto7, Adam G. Riess14, Adam G. Riess12, Michael Richmond15, Roger W. Romani11, Masao Sako16, Donald P. Schneider17, Mathew Smith13, Naohiro Takanashi8, Kouichi Tokita8, Kurt van der Heyden, Naoki Yasuda8, Chen Zheng11, Jennifer K. Adelman-McCarthy2, James Annis2, Roberto J. Assef7, J. C. Barentine18, J. C. Barentine19, Ralf Bender20, Roger Blandford11, William N. Boroski2, Malcolm N. Bremer21, Howard Brewington18, Chris A. Collins22, Arlin P. S. Crotts23, Jack Dembicky18, Jason D. Eastman7, Alastair C. Edge24, Edmond Edmondson13, Edward C. Elson, Michael E. Eyler25, Alexei V. Filippenko26, Ryan J. Foley26, Stephan Frank7, Ariel Goobar27, Tina Gueth10, James E. Gunn28, Michael Harvanek18, Michael Harvanek29, Ulrich Hopp20, Yutaka Ihara8, Želko Ivezić4, Steven M. Kahn11, Jared Kaplan30, Stephen B. H. Kent2, Stephen B. H. Kent1, William Ketzeback18, S. J. Kleinman31, S. J. Kleinman18, Wolfram Kollatschny32, Richard G. Kron1, Jurek Krzesinski18, D. Lamenti33, Giorgos Leloudas34, Huan Lin2, Dan Long18, John R. Lucey24, Robert H. Lupton28, Elena Malanushenko18, Viktor Malanushenko18, Russet McMillan18, Javier Méndez35, Christopher W. Morgan7, Christopher W. Morgan25, Tomoki Morokuma8, Atsuko Nitta18, Linda Ostman27, Kaike Pan18, Constance M. Rockosi36, A. Kathy Romer37, Pilar Ruiz-Lapuente35, G. Saurage18, K. Schlesinger7, Stephanie A. Snedden18, Jesper Sollerman27, Jesper Sollerman34, Chris Stoughton2, Maximilian Stritzinger34, Mark SubbaRao1, Douglas L. Tucker2, Petri Väisänen, Linda C. Watson7, S. Watters18, J. Craig Wheeler19, Brian Yanny2, Donald G. York1 
TL;DR: The Sloan Digital Sky Survey-II (SDSS-II) as mentioned in this paper is a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band imaging over an area of 300 sq. deg.
Abstract: The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. The survey region is a stripe 2.5° wide centered on the celestial equator in the Southern Galactic Cap that has been imaged numerous times in earlier years, enabling construction of a deep reference image for the discovery of new objects. Supernova imaging observations are being acquired between September 1 and November 30 of 2005-7. During the first two seasons, each region was imaged on average every five nights. Spectroscopic follow-up observations to determine supernova type and redshift are carried out on a large number of telescopes. In its first two three-month seasons, the survey has discovered and measured light curves for 327 spectroscopically confirmed SNe Ia, 30 probable SNe Ia, 14 confirmed SNe Ib/c, 32 confirmed SNe II, plus a large number of photometrically identified SNe Ia, 94 of which have host-galaxy spectra taken so far. This paper provides an overview of the project and briefly describes the observations completed during the first two seasons of operation.

Journal ArticleDOI
TL;DR: The present review examines the major issues pertaining to how to best conceptualize and measure life stress, for they will be crucial to resolve if progress is to be made in understanding ways in which life stress may or may not contribute to psychological and physical disorders.
Abstract: The idea that adverse life circumstances and negative life events contribute to disorder and disease has long been held. Advances in conceptualizing and defining these conditions under the common label of life stress have led to progress in measuring both the environmental and individual response characteristics that may promote disorder and disease. In general, a substantial and growing research literature supports the basic premise that life stress plays an important role in the development of many psychological and physical problems. Recent research, too, strongly suggests that interest in life stress in relation to health and disease will accelerate over the coming years. Yet debates and controversies remain concerning how to best conceptualize and measure life stress, which presents distinctive challenges for advancing the field. The present review examines the major issues pertaining to these debates, controversies, and challenges, for they will be crucial to resolve if progress is to be made in und...

Journal ArticleDOI
01 Feb 2008-EPL
TL;DR: It is found that for human dynamics memory is weak, and the bursty character is due to the changes in the interevent time distribution, and it is shown that current models lack in their ability to reproduce the activity pattern observed in real systems, opening up avenues for future work.
Abstract: The dynamics of a wide range of real systems, from email patterns to earthquakes, display a bursty, intermittent nature, characterized by short timeframes of intense activity followed by long times of no or reduced activity. The understanding of the origin of such bursty patterns is hindered by the lack of tools to compare different systems using a common framework. Here we propose to characterize the bursty nature of real signals using orthogonal measures quantifying two distinct mechanisms leading to burstiness: the interevent time distribution and the memory. We find that while the burstiness of natural phenomena is rooted in both the interevent time distribution and memory, for human dynamics memory is weak, and the bursty character is due to the changes in the interevent time distribution. Finally, we show that current models lack in their ability to reproduce the activity pattern observed in real systems, opening up avenues for future work. Copyright c �EPLA, 2008

Journal ArticleDOI
TL;DR: A basin-to-channel-scale implementation of the Advanced Circulation (ADCIRC) unstructured grid hydrodynamic model has been developed that accurately simulates hurricane storm surge, tides, and river flow in this complex region as mentioned in this paper.
Abstract: Southern Louisiana is characterized by low-lying topography and an extensive network of sounds, bays, marshes, lakes, rivers, and inlets that permit widespread inundation during hurricanes. A basin- to channel-scale implementation of the Advanced Circulation (ADCIRC) unstructured grid hydrodynamic model has been developed that accurately simulates hurricane storm surge, tides, and river flow in this complex region. This is accomplished by defining a domain and computational resolution appropriate for the relevant processes, specifying realistic boundary conditions, and implementing accurate, robust, and highly parallel unstructured grid numerical algorithms. The model domain incorporates the western North Atlantic, the Gulf of Mexico, and the Caribbean Sea so that interactions between basins and the shelf are explicitly modeled and the boundary condition specification of tidal and hurricane processes can be readily defined at the deep water open boundary. The unstructured grid enables highly refi...

Journal ArticleDOI
TL;DR: The goal of this work is to understand how the linewidth of the localized surface plasmon resonance depends on the size, shape, and environment of the nanoparticles.
Abstract: This article provides a review of our recent Rayleigh scattering measurements on single metal nanoparticles. Two different systems will be discussed in detail: gold nanorods with lengths between 30 and 80 nm, and widths between 8 and 30 nm; and hollow gold-silver nanocubes (termed nanoboxes or nanocages depending on their exact morphology) with edge lengths between 100 and 160 nm, and wall thicknesses of the order of 10 nm. The goal of this work is to understand how the linewidth of the localized surface plasmon resonance depends on the size, shape, and environment of the nanoparticles. Specifically, the relative contributions from bulk dephasing, electron-surface scattering, and radiation damping (energy loss via coupling to the radiation field) have been determined by examining particles with different dimensions. This separation is possible because the magnitude of the radiation damping effect is proportional to the particle volume, whereas, the electron-surface scattering contribution is inversely proportional to the dimensions. For the nanorods, radiation damping is the dominant effect for thick rods (widths greater than 20 nm), while electron-surface scattering is dominant for thin rods (widths less than 10 nm). Rods with widths in between these limits have narrow resonances-approaching the value determined by the bulk contribution. For nanoboxes and nanocages, both radiation damping and electron-surface scattering are significant at all sizes. This is because these materials have thin walls, but large edge lengths and, therefore, relatively large volumes. The effect of the environment on the localized surface plasmon resonance has also been studied for nanoboxes. Increasing the dielectric constant of the surroundings causes a red-shift and an increase in the linewidth of the plasmon band. The increase in linewidth is attributed to enhanced radiation damping.

Journal ArticleDOI
TL;DR: In this article, the authors compare the chemical abundances at the sites of 12 nearby (z < 0.14) Type Ic supernovae (SN Ic) that showed broad lines, but had no observed gamma-ray burst (GRB), with the chemical abundance in five nearby galaxies at the site of GRBs where broad-lined SN Ic were seen after the fireball had faded.
Abstract: We compare the chemical abundances at the sites of 12 nearby (z < 0.14) Type Ic supernovae (SN Ic) that showed broad lines, but had no observed gamma-ray burst (GRB), with the chemical abundances in five nearby (z < 0.25) galaxies at the sites of GRBs where broad-lined SN Ic were seen after the fireball had faded. It has previously been noted that GRB hosts are low in luminosity and low in their metal abundances. If low metallicity is sufficient to force the evolution of massive stars to end their lives as GRBs with an accompanying broad-lined SN Ic, then we would expect higher metal abundances for the broad-lined SN Ic that have no detected GRBs. This is what we observe, and this trend is independent of the choice of metallicity calibration we adopt and the mode of SN survey that found the broad-lined SN Ic. A unique feature of this analysis is that we present new spectra of the host galaxies and analyze all measurements of both samples in the same set of methods, using the galaxy emission-line measurements corrected for extinction and stellar absorption, via independent metallicity diagnostics of Kewley & Dopita, McGaugh, and Pettini & Pagel. In our small sample, the boundary between galaxies that have GRBs accompanying their broad-lined SN Ic and those that have broad-lined SN Ic without GRBs lies at an oxygen abundance of 12 + log(O/H)KD02 ~ 8.5, which corresponds to 0.2-0.6 Z☉ depending on the adopted metallicity scale and solar abundance value. Even when we limit the comparison to SN Ic that were found in untargeted supernova surveys, the environment of every broad-lined SN Ic that had no GRB is more metal rich than the site of any broad-lined SN Ic where a GRB was detected.


Journal ArticleDOI
Martti Raidal, A. van der Schaaf1, Ikaros I.Y. Bigi2, Michelangelo L. Mangano3, Yannis K. Semertzidis4, Steven Abel5, S. Albino6, Stefan Antusch7, Ernesto Arganda8, Borut Bajc, Sw. Banerjee9, Carla Biggio7, Monika Blanke10, Monika Blanke7, W. Bonivento11, Gustavo C. Branco12, Gustavo C. Branco3, Douglas Bryman13, Andrzej J. Buras10, Lorenzo Calibbi14, Lorenzo Calibbi15, Augusto Ceccucci3, Piotr H. Chankowski16, Sacha Davidson17, Aldo Deandrea17, David DeMille18, Frank F. Deppisch19, Marco Aurelio Diaz, Björn Duling10, Marta Felcini3, W. Fetscher, F. Forti20, Dilip Kumar Ghosh, Manuel Giffels21, Mario Giorgi20, Gian F. Giudice3, E. Goudzovskij, Tao Han22, Philip Harris23, Maria J. Herrero8, Junji Hisano24, R. J. Holt25, Katri Huitu26, Alejandro Ibarra, Olga Igonkina27, Amon Ilakovac28, J. Imazato29, Gino Isidori, Filipe R. Joaquim8, Mario Kadastik, Y. Kajiyama, Stephen F. King30, Klaus Kirch31, Mikhail Kozlov32, Maria Krawczyk3, Maria Krawczyk16, Thomas Kress21, Oleg Lebedev3, Alberto Lusiani20, Ernest Ma33, G. Marchiori20, A. Masiero, Isabella Masina3, G. Moreau34, Takehiko Mori24, M. Muntel, Nicola Neri20, Fabrizio Nesti, C. J. G. Onderwater, Paride Paradisi35, S. T. Petcov15, S. T. Petcov36, M. Picariello37, V. Porretti14, Anton Poschenrieder10, Maxim Pospelov9, L. Rebane, M. N. Rebelo3, M. N. Rebelo12, Adam Ritz9, L. Roberts38, Andrea Romanino15, J. M. Roney9, A. M. Rossi, Reinhold Rückl39, Goran Senjanovic40, Nicola Serra11, Tetsuo Shindou, Y. Takanishi15, Cecilia Tarantino10, A. M. Teixeira34, E. Torrente-Lujan41, K. J. Turzynski16, K. J. Turzynski42, T. E. J. Underwood5, Sudhir K. Vempati43, Oscar Vives14 
TL;DR: In this article, the authors discuss the theoretical, phenomenological and experimental issues related to flavor phenomena in the charged lepton sector and in flavor conserving CP-violating processes.
Abstract: This chapter of the report of the “Flavor in the era of the LHC” Workshop discusses the theoretical, phenomenological and experimental issues related to flavor phenomena in the charged lepton sector and in flavor conserving CP-violating processes. We review the current experimental limits and the main theoretical models for the flavor structure of fundamental particles. We analyze the phenomenological consequences of the available data, setting constraints on explicit models beyond the standard model, presenting benchmarks for the discovery potential of forthcoming measurements both at the LHC and at low energy, and exploring options for possible future experiments.

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TL;DR: Simulations conclusively demonstrate that the slow translational and rotational dynamics, which are manifest in the high viscosity, may be attributable to the formation of a strong, pervasive hydrogen-bonded network.
Abstract: The capture of CO2 from fossil fuel combustion, particularly in coal-fired power plants, represents a critical component of efforts aimed at stabilizing greenhouse gas levels in the atmosphere. Alkanolamines have traditionally been used to this end; however, drawbacks such as volatility, degradation, and regeneration costs have been drivers for the development of new, superior technologies. Recently, several seminal studies with ionic liquids (ILs), both experimental and computational, have demonstrated their potential as CO2 capture agents. In traditional ILs, experimental studies with CO2 have revealed its unusually high physical solubility in these media. Complementary simulation studies have provided evidence that this is attributable to CO2 occupying void space within the liquid and favorably interacting with the anion. Recently, a series of second-generation task-specific ionic liquids (TSILs) containing amine functional groups have been synthesized and demonstrated to have much higher capacities fo...

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TL;DR: Some of the major applications of NMR in drug discovery, focusing on hit and lead generation, are highlighted, and a critical analysis of its current and potential utility is provided.
Abstract: In the past decade, the potential of harnessing the ability of nuclear magnetic resonance (NMR) spectroscopy to monitor intermolecular interactions as a tool for drug discovery has been increasingly appreciated in academia and industry. In this Perspective, we highlight some of the major applications of NMR in drug discovery, focusing on hit and lead generation, and provide a critical analysis of its current and potential utility.

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TL;DR: This paper found that exposure to an open classroom climate at school can partially compensate for the disadvantages of young people with low socioeconomic status, even when controlling for individual, classroom, school, and district characteristics.
Abstract: Does civics instruction have an impact on the political engagement of adolescents? If so, how? Analysis of data from CIVED, a major study of civic education conducted in 1999, finds that an open classroom climate has a positive impact on adolescents’ civic knowledge and appreciation of political conflict, even upon controlling for numerous individual, classroom, school, and district characteristics. Furthermore, an open classroom environment fosters young people’s intention to be an informed voter. Results further show that exposure to an open classroom climate at school can partially compensate for the disadvantages of young people with low socioeconomic status.

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TL;DR: In this paper, a review examines recent advances in sample size planning, not only from the perspective of an individual researcher, but also with regard to the goal of developing cumulative knowledge.
Abstract: This review examines recent advances in sample size planning, not only from the perspective of an individual researcher, but also with regard to the goal of developing cumulative knowledge. Psychologists have traditionally thought of sample size planning in terms of power analysis. Although we review recent advances in power analysis, our main focus is the desirability of achieving accurate parameter estimates, either instead of or in addition to obtaining sufficient power. Accuracy in parameter estimation (AIPE) has taken on increasing importance in light of recent emphasis on effect size estimation and formation of confidence intervals. The review provides an overview of the logic behind sample size planning for AIPE and summarizes recent advances in implementing this approach in designs commonly used in psychological research.