Showing papers by "University of Wisconsin–Milwaukee published in 2012"
TL;DR: The structural reformation of graphene, from pore generation to morphology transformation, is receiving growing attention, because the reconstruction of graphene could potentially result in localized highly reactive regions and thus unexpected properties for specifi c applications.
Abstract: Continuous scientifi c endeavors have been directed toward the optimization of graphene by manipulating its electronic, mechanical, chemical, and structural properties, such as surface area, pore geometry, and functional sites, in order to advance various potential applications, including nanoelectronics, energy storage/conversion, and catalysis. [ 1 ] The structural reformation of graphene, from pore generation to morphology transformation, is receiving growing attention, because the reconstruction of graphene could potentially result in localized highly reactive regions and thus unexpected properties for specifi c applications. [ 2 ] For instance, it was reported that crumpled graphene allows for the fabrication of polymer-graphene nanocomposite fi lms with low O 2 permeability and effective reduction of transparency. [ 3 ] Chemical functionalization of graphene (e.g., graphene oxide or GO) is another effective method for manipulating physical and chemical properties of graphene, because enriched reactive oxygen functional groups in GO can provide ample covalent bonding sites for the chemical functionalization. The functionalized GO can be easily converted to graphene-like materials through chemical or thermal reduction of GO. [ 4 ] For instance, nitrogen-doped graphene (NG) can be synthesized through thermal annealing of GO in ammonia, and the resulting NG showed some unique properties including improved conductivity and excellent catalytic activity. Actually, NG has been intensively investigated as electrode materials for lithium-ion batteries, catalysts for oxygen reduction reac-
871 citations
University of California, San Diego1, Lamont–Doherty Earth Observatory2, Goddard Institute for Space Studies3, University of Connecticut4, United States Geological Survey5, North Dakota State University6, State Street Corporation7, McGill University8, University of British Columbia9, University of Maryland, College Park10, National Center for Atmospheric Research11, Lund University12, Swedish University of Agricultural Sciences13, University of California, Santa Barbara14, Denver Federal Center15, University of Maine16, University of Plymouth17, University of Texas at Austin18, Swiss Institute of Bioinformatics19, University of Lausanne20, University of Wisconsin–Milwaukee21
TL;DR: In this paper, the authors compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius).
Abstract: Warming experiments are increasingly relied on to estimate plant responses to global climate change. For experiments to provide meaningful predictions of future responses, they should reflect the empirical record of responses to temperature variability and recent warming, including advances in the timing of flowering and leafing. We compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius). We show that warming experiments underpredict advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. For species that were common to both study types, the experimental results did not match the observational data in sign or magnitude. The observational data also showed that species that flower earliest in the spring have the highest temperature sensitivities, but this trend was not reflected in the experimental data. These significant mismatches seem to be unrelated to the study length or to the degree of manipulated warming in experiments. The discrepancy between experiments and observations, however, could arise from complex interactions among multiple drivers in the observational data, or it could arise from remediable artefacts in the experiments that result in lower irradiance and drier soils, thus dampening the phenological responses to manipulated warming. Our results introduce uncertainty into ecosystem models that are informed solely by experiments and suggest that responses to climate change that are predicted using such models should be re-evaluated.
751 citations
TL;DR: In this article, the authors studied CO2 photoreduction with water vapor on three TiO2 nanocrystal polymorphs (anatase, rutile, and brookite) that were engineered with defect-free and oxygen-deficient surfaces.
Abstract: CO2 photoreduction with water vapor has been studied on three TiO2 nanocrystal polymorphs (anatase, rutile, and brookite) that were engineered with defect-free and oxygen-deficient surfaces, respectively. It was demonstrated that helium pretreatment of the as-prepared TiO2 at a moderate temperature resulted in the creation of surface oxygen vacancies (VO) and Ti3+ sites on anatase and brookite but not on rutile. The production of CO and CH4 from CO2 photoreduction was remarkably enhanced on defective anatase and brookite TiO2 (up to 10-fold enhancement) as compared to the defect-free surfaces. Defective brookite was photocatalytically more active than anatase and rutile, probably because of a lower formation energy of VO on brookite. The results from in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analyses suggested that (1) defect-free TiO2 was not active for CO2 photoreduction since no CO2– is generated, and (2) CO2 photoreduction to CO possibly underwent different reaction ...
727 citations
European Southern Observatory1, Yale University2, Leiden University3, Max Planck Society4, Harvard University5, University of Wisconsin–Milwaukee6, University of Arizona7, University of California, Santa Cruz8, Tufts University9, Carnegie Learning10, California Institute of Technology11, University of Wisconsin-Madison12
TL;DR: 3D-HST as discussed by the authors is a near-infrared spectroscopic Treasury program with the Hubble Space Telescope for studying the physical processes that shape galaxies in the distant universe.
Abstract: We present 3D-HST, a near-infrared spectroscopic Treasury program with the Hubble Space Telescope for studying
the physical processes that shape galaxies in the distant universe. 3D-HST provides rest-frame optical spectra for
a sample of ∼7000 galaxies at 1 < z < 3.5, the epoch when ∼60% of all star formation took place, the number
density of quasars peaked, the first galaxies stopped forming stars, and the structural regularity that we see in
galaxies today must have emerged. 3D-HST will cover three quarters (625 arcmin^2) of the CANDELS Treasury
survey area with two orbits of primary WFC3/G141 grism coverage and two to four orbits with the ACS/G800L
grism in parallel. In the IR, these exposure times yield a continuum signal-to-noise ratio of ∼5 per resolution element
at H_140 ∼ 23.1 and a 5σ emission-line sensitivity of ∼5 × 10^(−17) erg s^−1 cm^(−2) for typical objects, improving by
a factor of ∼2 for compact sources in images with low sky background levels. The WFC3/G141 spectra provide
continuous wavelength coverage from 1.1 to 1.6μm at a spatial resolution of ∼0."13, which, combined with their
depth, makes them a unique resource for studying galaxy evolution. We present an overview of the preliminary
reduction and analysis of the grism observations, including emission-line and redshift measurements from combined
fits to the extracted grism spectra and photometry from ancillary multi-wavelength catalogs. The present analysis
yields redshift estimates with a precision of σ(z) = 0.0034(1 + z), or σ(v) ≈ 1000 km s^(−1). We illustrate how
the generalized nature of the survey yields near-infrared spectra of remarkable quality for many different types
of objects, including a quasar at z = 4.7, quiescent galaxies at z ∼ 2, and the most distant T-type brown dwarf
star known. The combination of the CANDELS and 3D-HST surveys will provide the definitive imaging and
spectroscopic data set for studies of the 1 < z < 3.5 universe until the launch of the James Webb Space Telescope.
723 citations
TL;DR: In this article, the authors compute the Galactic merger rates for NS-NS, BH-BH, and BH -BH mergers with the StarTrack code and show that the binding energy of the envelope plays a pivotal role in determining whether a binary merges within a Hubble time.
Abstract: The last decade of observational and theoretical developments in stellar and binary evolution provides an opportunity to incorporate major improvements to the predictions from population synthesis models. We compute the Galactic merger rates for NS-NS, BH-NS, and BH-BH mergers with the StarTrack code. The most important revisions include updated wind mass-loss rates (allowing for stellar-mass black holes up to 80 M {sub Sun }), a realistic treatment of the common envelope phase (a process that can affect merger rates by 2-3 orders of magnitude), and a qualitatively new neutron star/black hole mass distribution (consistent with the observed {sup m}ass gap{sup )}. Our findings include the following. (1) The binding energy of the envelope plays a pivotal role in determining whether a binary merges within a Hubble time. (2) Our description of natal kicks from supernovae plays an important role, especially for the formation of BH-BH systems. (3) The masses of BH-BH systems can be substantially increased in the case of low metallicities or weak winds. (4) Certain combinations of parameters underpredict the Galactic NS-NS merger rate and can be ruled out. (5) Models incorporating delayed supernovae do not agree with the observed NS/BH 'mass gap', in accordance with our previousmore » work. This is the first in a series of three papers. The second paper will study the merger rates of double compact objects as a function of redshift, star formation rate, and metallicity. In the third paper, we will present the detection rates for gravitational-wave observatories, using up-to-date signal waveforms and sensitivity curves.« less
678 citations
TL;DR: Experimental results indicated that CNTs-A have excellent adsorption capacity for methyl orange and methylene blue, and Kinetic regression results shown that the adsorbent kinetic was more accurately represented by a pseudo second-order model than Langmuir isotherm model.
Abstract: An alkali-acitvated method was explored to synthesize activated carbon nanotubes (CNTs-A) with a high specific surface area (SSA), and a large number of mesopores. The resulting CNTs-A were used as an adsorbent material for removal of anionic and cationic dyes in aqueous solutions. Experimental results indicated that CNTs-A have excellent adsorption capacity for methyl orange (149 mg/g) and methylene blue (399 mg/g). Alkali-activation treatment of CNTs increased the SSA and pore volume (PV), and introduced oxygen-containing functional groups on the surface of CNTs-A, which would be beneficial to improving the adsorption affinity of CNTs-A for removal of dyes. Kinetic regression results shown that the adsorption kinetic was more accurately represented by a pseudo second-order model. The overall adsorption process was jointly controlled by external mass transfer and intra-particle diffusion, and intra-particle diffusion played a dominant role. Freundlich isotherm model showed a better fit with adsorption da...
617 citations
TL;DR: Details on the FINDCHIRP algorithm as used in the search for subsolar mass binaries, binary neutron stars, neutron starblack hole binaries, and binary black holes are provided.
Abstract: Matched-filter searches for gravitational waves from coalescing compact binaries by the LIGO
Scientific Collaboration use the FINDCHIRP algorithm: an implementation of the optimal filter with
innovations to account for unknown signal parameters and to improve performance on detector data
that has nonstationary and non-Gaussian artifacts. We provide details on the FINDCHIRP algorithm as used
in the search for subsolar mass binaries, binary neutron stars, neutron starblack hole binaries, and binary
black holes.
528 citations
TL;DR: A cost-effective route for the preparation of Fe(3) C-based core-shell structured catalysts for oxygen reduction reactions was developed, which features an ultralow cost and excellent long-term stability suitable for mass production.
Abstract: A cost-effective route for the preparation of Fe(3) C-based core-shell structured catalysts for oxygen reduction reactions was developed. The novel catalysts generated a much higher power density (i.e., three times higher at R(ex) of 1 Ω) than the Pt/C in microbial fuel cells. Furthermore, the N-Fe/Fe(3)C@C features an ultralow cost and excellent long-term stability suitable for mass production.
505 citations
TL;DR: Graphene oxide (GO) has attracted intense interest for its use as a precursor material for the mass production of graphene-based materials, which hold great potential in various applications.
Abstract: Graphene oxide (GO) has attracted intense interest for its use as a precursor material for the mass production of graphene-based materials, which hold great potential in various applications. Insights into the structure of GO and reduced GO (RGO) are of significant interest, as their properties are dependent on the type and distribution of functional groups, defects, and holes from missing carbons in the GO carbon lattice. Modeling the structural motifs of GO can predict the structural evolution in its reduction and presents promising directions to tailor the properties of RGO. Two general reduction approaches, chemical and thermal, are proposed to achieve highly reduced GO materials. This review introduces typical chemical oxidation methods to produce GO from pure graphite, then summarizes the modeling progress on the GO structure and its oxidation and reduction dynamics, and lastly, presents the recent progress of RGO preparation through chemical and thermal reduction approaches. By summarizing recent studies on GO structural modeling and its reduction, this review leads to a deeper understanding of GO morphology and reduction path, and suggests future directions for the scalable production of graphene-based materials through atomic engineering.
481 citations
University of Leeds1, James Cook University2, University College London3, Ulster University4, Universiti Brunei Darussalam5, Forestry Commission6, New York Botanical Garden7, Museu Paraense Emílio Goeldi8, University of Exeter9, Universidad Autónoma Gabriel René Moreno10, Wageningen University and Research Centre11, University of Amsterdam12, University of Edinburgh13, Universidad Nacional de la Amazonía Peruana14, Paul Sabatier University15, National Park Service16, University of Texas at Austin17, Forestry Research Institute of Ghana18, University of São Paulo19, Smithsonian Institution20, Hokkaido University21, National University of Colombia22, Forest Research Institute Malaysia23, Conservation International24, University of Twente25, Environmental Change Institute26, Universidade do Estado de Mato Grosso27, University of York28, Commonwealth Scientific and Industrial Research Organisation29, University of Cambridge30, Duke University31, University of Los Andes32, Karlsruhe Institute of Technology33, Universidade Federal do Acre34, University of Yaoundé I35, Naturalis36, University of Wisconsin–Milwaukee37, Smithsonian Tropical Research Institute38, University of Stirling39
TL;DR: In this article, the effect of tree height (H) on tropical forest biomass and carbon storage estimates was investigated using data from 20 sites across four continents, and the results showed that tree H is an important allometric factor that needs to be included in future forest biomass estimates to reduce error in estimates of tropical carbon stocks and emissions.
Abstract: . Aboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer the following questions: 1. What is the best H-model form and geographic unit to include in biomass models to minimise site-level uncertainty in estimates of destructive biomass? 2. To what extent does including H estimates derived in (1) reduce uncertainty in biomass estimates across all 327 plots? 3. What effect does accounting for H have on plot- and continental-scale forest biomass estimates? The mean relative error in biomass estimates of destructively harvested trees when including H (mean 0.06), was half that when excluding H (mean 0.13). Power- and Weibull-H models provided the greatest reduction in uncertainty, with regional Weibull-H models preferred because they reduce uncertainty in smaller-diameter classes (≤40 cm D) that store about one-third of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows that including H reduces errors from 41.8 Mg ha−1 (range 6.6 to 112.4) to 8.0 Mg ha−1 (−2.5 to 23.0). For all plots, aboveground live biomass was −52.2 Mg ha−1 (−82.0 to −20.3 bootstrapped 95% CI), or 13%, lower when including H estimates, with the greatest relative reductions in estimated biomass in forests of the Brazilian Shield, east Africa, and Australia, and relatively little change in the Guiana Shield, central Africa and southeast Asia. Appreciably different stand structure was observed among regions across the tropical continents, with some storing significantly more biomass in small diameter stems, which affects selection of the best height models to reduce uncertainty and biomass reductions due to H. After accounting for variation in H, total biomass per hectare is greatest in Australia, the Guiana Shield, Asia, central and east Africa, and lowest in east-central Amazonia, W. Africa, W. Amazonia, and the Brazilian Shield (descending order). Thus, if tropical forests span 1668 million km2 and store 285 Pg C (estimate including H), then applying our regional relationships implies that carbon storage is overestimated by 35 Pg C (31–39 bootstrapped 95% CI) if H is ignored, assuming that the sampled plots are an unbiased statistical representation of all tropical forest in terms of biomass and height factors. Our results show that tree H is an important allometric factor that needs to be included in future forest biomass estimates to reduce error in estimates of tropical carbon stocks and emissions due to deforestation.
426 citations
TL;DR: This paper reviewed the empirical research that has investigated individual choices, challenges, and career consequences associated with various types of global work, and then developed a taxonomy of the global work experiences.
TL;DR: In this paper, the authors compute the Galactic merger rates for NS-NS, BH-BH, and BH -BH mergers with the StarTrack code and show that the binding energy of the envelope plays a pivotal role in determining whether a binary merges within a Hubble time.
Abstract: The last decade of observational and theoretical developments in stellar and binary evolution provides an opportunity to incorporate major improvements to the predictions from populations synthesis models. We compute the Galactic merger rates for NS-NS, BH-NS, and BH-BH mergers with the StarTrack code. The most important revisions include: updated wind mass loss rates (allowing for stellar mass black holes up to $80 \msun$), a realistic treatment of the common envelope phase (a process that can affect merger rates by 2--3 orders of magnitude), and a qualitatively new neutron star/black hole mass distribution (consistent with the observed "mass gap"). Our findings include: (i) The binding energy of the envelope plays a pivotal role in determining whether a binary merges within a Hubble time. (ii) Our description of natal kicks from supernovae plays an important role, especially for the formation of BH-BH systems. (iii) The masses of BH-BH systems can be substantially increased in the case of low metallicities or weak winds. (iv) Certain combinations of parameters underpredict the Galactic NS-NS merger rate, and can be ruled out. {\em (v)} Models incorporating delayed supernovae do not agree with the observed NS/BH "mass gap", in accordance with our previous work. This is the first in a series of three papers. The second paper will study the merger rates of double compact objects as a function of redshift, star formation rate, and metallicity. In the third paper we will present the detection rates for gravitational wave observatories, using up-to-date signal waveforms and sensitivity curves.
TL;DR: In this paper, a large sample of spectroscopically confirmed star-forming galaxies at redshifts 1.4 ≤ z/(spec) ≤ 3.7, with complementary imaging in the near and mid-IR from the ground and from the Hubble Space Telescope and the Spitzer Space Telescope, is used to infer the average star formation histories (SFHs) of typical galaxies from z ∼ 2============to 7.6.
Abstract: A large sample of spectroscopically confirmed star-forming galaxies at redshifts 1.4 ≤ z_(spec) ≤ 3.7, with
complementary imaging in the near- and mid-IR from the ground and from the Hubble Space Telescope and
Spitzer Space Telescope, is used to infer the average star formation histories (SFHs) of typical galaxies from z ∼ 2
to 7. For a subset of 302 galaxies at 1.5 ≤ z_(spec) < 2.6, we perform a detailed comparison of star formation rates
(SFRs) determined from spectral energy distribution (SED) modeling (SFRs[SED]) and those calculated from deep
Keck UV and Spitzer/MIPS 24μm imaging (SFRs[IR+UV]). Exponentially declining SFHs yield SFRs[SED]
that are 5–10 times lower on average than SFRs[IR+UV], indicating that declining SFHs may not be accurate for
typical galaxies at z ≳ 2. The SFRs of z ∼ 2–3 galaxies are directly proportional to their stellar masses (M_*),
with unity slope—a result that is confirmed with Spitzer/IRAC stacks of 1179 UV-faint (R > 25.5) galaxies—for
M_* ≳ 5 × 10^8M_⊙ and SFRs ≳ 2M_⊙ yr^(−1). We interpret this result in the context of several systematic biases that
can affect determinations of the SFR–M_* relation. The average specific SFRs at z ∼ 2–3 are remarkably similar
within a factor of two to those measured at z ≳ 4, implying that the average SFH is one where SFRs increase with
time. A consequence of these rising SFHs is that (1) a substantial fraction of UV-bright z ∼ 2–3 galaxies had faint
sub-L* progenitors at z ≳ 4; and (2) gas masses must increase with time from z = 2 to 7, over which time the
net cold gas accretion rate—as inferred from the specific SFR and the Kennicutt–Schmidt relation—is ∼2–3 times
larger than the SFR. However, if we evolve to higher redshift the SFHs and masses of the halos that are expected
to host L* galaxies at z ∼ 2, then we find that ≾10% of the baryons accreted onto typical halos at z ≳ 4 actually
contribute to star formation at those epochs. These results highlight the relative inefficiency of star formation even
at early cosmic times when galaxies were first assembling.
TL;DR: The recent development of analytical techniques and methods enables accurate selenium measurements of environmental concentrations, which will lead to a better understanding of biogeochemical processes, which may enable us to predict the distribution of Se health hazards in areas where this is currently unknown.
Abstract: Selenium is a natural trace element that is of fundamental importance to human health. The extreme geographical variation in selenium concentrations in soils and food crops has resulted in significant health problems related to deficient or excess levels of selenium in the environment. To deal with these kinds of problems in the future it is essential to get a better understanding of the processes that control the global distribution of selenium. The recent development of analytical techniques and methods enables accurate selenium measurements of environmental concentrations, which will lead to a better understanding of biogeochemical processes. This improved understanding may enable us to predict the distribution of selenium in areas where this is currently unknown. These predictions are essential to prevent future Se health hazards in a world that is increasingly affected by human activities.
TL;DR: Ivermectin, a broadly used anti-helminthic drug, proved to be a highly potent inhibitor of YFV replication and inhibited, although less efficiently, the replication of several other flaviviruses, i.e. dengue fever, Japanese encephalitis and tick-borne encephalopathy viruses.
Abstract: Objectives
Infection with yellow fever virus (YFV), the prototypic mosquito-borne flavivirus, causes severe febrile disease with haemorrhage, multi-organ failure and a high mortality. Moreover, in recent years the Flavivirus genus has gained further attention due to re-emergence and increasing incidence of West Nile, dengue and Japanese encephalitis viruses. Potent and safe antivirals are urgently needed.
TL;DR: In this paper, the authors studied four types of business ecosystems (Orchestra, Creative Bazaar, Jam Central, and MOD Station) and determined the success and failures of new ventures and established companies.
TL;DR: In this article, the authors present results from the Keck Baryonic Structure Survey (KBSS), a unique spectroscopic survey of the distant universe designed to explore the details of the connection between galaxies and intergalactic baryons.
Abstract: We present results from the Keck Baryonic Structure Survey (KBSS), a unique spectroscopic survey of the
distant universe designed to explore the details of the connection between galaxies and intergalactic baryons
within the same survey volumes, focusing particularly on scales from ∼ 50 kpc to a few Mpc. The KBSS is
optimized for the redshift range z ∼ 2-3, combining S/N ∼ 100 Keck/HIRES spectra of 15 of the brightest
QSOs in the sky at z ≃ 2.5-2.9 with very densely sampled galaxy redshift surveys within a few arcmin of each
QSO sightline. In this paper, we present quantitative results on the distribution, column density, kinematics,
and absorber line widths of neutral hydrogen (H_I) surrounding a subset of 886 KBSS star-forming galaxies
with 2.0 ≾ z ≾ 2.8 and with projected distances ≤ 3 physical Mpc from a QSO sightline. Using Voigt profile
decompositions of the full Lyα forest region of all 15 QSO spectra, we compiled a catalog of ∼6000 individual
absorbers in the redshift range of interest, with 12 ≤ log(N_(HI)) ≤ 21. These are used to measure H I absorption
statistics near the redshifts of foreground galaxies as a function of projected galactocentric distance from the
QSO sightline and for randomly chosen locations in the intergalacticmedium (IGM) within the survey volume.
We find that NHI and the multiplicity of velocity-associated H I components increase rapidly with decreasing
galactocentric impact parameter and as the systemic redshift of the galaxy is approached. The strongest H_I
absorbers within ≃ 100 physical kpc of galaxies have N_(HI) ∼ 3 orders of magnitude higher than those near
random locations in the IGM. The circumgalactic zone of most significantly enhanced H_I absorption is found
within transverse distances of ≾ 300 kpc and within ±300 km s^(-1) of galaxy systemic redshifts. Taking this
region as the defining bounds of the circumgalactic medium (CGM), nearly half of absorbers with log(N_(HI))
> 15.5 are found within the CGM of galaxies meeting our photometric selection criteria, while their CGM
occupy only 1.5% of the cosmic volume. The spatial covering fraction, multiplicity of absorption components,
and characteristic NHI remain significantly elevated to transverse distances of ∼2 physical Mpc from galaxies
in our sample. Absorbers with N_(HI) > 10^(14.5) cm^(-2) are tightly correlated with the positions of galaxies, while
absorbers with lower N_(HI) are correlated with galaxy positions only on ≳ Mpc scales. Redshift anisotropies
on these larger scales indicate coherent infall toward galaxy locations, while on scales of ∼ 100 physical kpc
peculiar velocities of Δv ≃ ±260 km s^(-1) with respect to the galaxies are indicated. The median Doppler widths
of individual absorbers within 1-3 r_(vir) of galaxies are larger by ≃ 50% than randomly chosen absorbers of the
same NHI, suggesting higher gas temperatures and/or increased turbulence likely caused by some combination
of accretion shocks and galactic winds around galaxies with M_(halo) ≃ 10^(12) M_⊙ at z ∼ 2-3.
TL;DR: In this article, the authors compare the generation of WOM (i.e., consumers sharing information about their own experiences) with the transmission of WOM, i.e. consumers passing on information about experiences they heard occurred to others.
Abstract: Previous research on word of mouth (WOM) has presented inconsistent evidence on whether consumers are more inclined to share positive or negative information about products and services. Some findings suggest that consumers are more inclined to engage in positive WOM, whereas others suggest that consumers are more inclined to engage in negative WOM. The present research offers a theoretical perspective that provides a means to resolve these seemingly contradictory findings. Specifically, the authors compare the generation of WOM (i.e., consumers sharing information about their own experiences) with the transmission of WOM (i.e., consumers passing on information about experiences they heard occurred to others). They suggest that a basic human motive to self-enhance leads consumers to generate positive WOM (i.e., share information about their own positive consumption experiences) but transmit negative WOM (i.e., pass on information they heard about others' negative consumption experiences). The aut...
TL;DR: Even surfaces with very high receding CA may have strong adhesion to ice if the size of the cracks is small, because the force needed to detach a piece of ice depends on the recedingCA and the initial size of interfacial cracks.
Abstract: We discuss mechanical forces that act upon a water droplet and a piece of ice on a rough solid surface and the difference between dewetting and ice fracture. The force needed to detach a water droplet depends on contact angle (CA) hysteresis and can be reduced significantly in the case of a superhydrophobic surface. The force needed to detach a piece of ice depends on the receding CA and the initial size of interfacial cracks. Therefore, even surfaces with very high receding CA may have strong adhesion to ice if the size of the cracks is small.
TL;DR: Demand-side research has been used to explain and predict those managerial decisions that increase value creation within a value system as discussed by the authors, emphasizing product markets as key sources of value-creation strategies for firms.
TL;DR: In this article, an ultrasound-assisted impregnation method was used to synthesize Mn-Ce mixed oxides (MnCe/Ti) to oxidize elemental mercury (Hg 0 ) at low temperatures in simulated low-rank (sub-bituminous and lignite) coal combustion flue gas and corresponding selective catalytic reduction (SCR) flue gases.
Abstract: TiO 2 supported Mn-Ce mixed oxides (Mn-Ce/Ti) synthesized by an ultrasound-assisted impregnation method were employed to oxidize elemental mercury (Hg 0 ) at low temperatures in simulated low-rank (sub-bituminous and lignite) coal combustion flue gas and corresponding selective catalytic reduction (SCR) flue gas. The catalysts were characterized by BET surface area analysis, X-ray diffraction (XRD) measurement and X-ray photoelectron spectroscopy (XPS) analysis. The combination of MnO x and CeO 2 resulted in significant synergy for Hg 0 oxidation. The Mn-Ce/Ti catalyst was highly active for Hg 0 oxidation at low temperatures (150–250 °C) under both simulated flue gas and SCR flue gas. The dominance of Mn 4+ and the presence of Ce 3+ on the Mn-Ce/Ti catalyst were responsible for its excellent catalytic performance. Hg 0 oxidation on the Mn-Ce/Ti catalyst likely followed the Langmuir–Hinshelwood mechanism, where reactive species on catalyst surface react with adjacently adsorbed Hg 0 to form Hg 2+ . NH 3 consumed the surface oxygen and limited the adsorption of Hg 0 , hence inhibiting Hg 0 oxidation over Mn-Ce/Ti catalyst. However, once NH 3 was cut off, the inhibited mercury oxidation activity could be completely recovered in the presence of O 2 . This study revealed the possibility of simultaneously oxidizing Hg 0 and reducing NO x at low flue gas temperatures. Such knowledge is of fundamental importance in developing effective and economical mercury and NO x control technologies for coal-fired power plants.
TL;DR: In this article, two types of graphene materials with very different morphologies, namely flat sheets of paper and crumpled particles, were used to modify anode and cathode electrodes in MFCs.
TL;DR: In this paper, a novel and selective gas-sensing platform with reduced graphene oxide (RGO) decorated with tin oxide (SnO2) nanocrystals (NCs) was presented.
Abstract: We report a novel and selective gas-sensing platform with reduced graphene oxide (RGO) decorated with tin oxide (SnO2) nanocrystals (NCs). This hybrid SnO2 NC–RGO platform showed enhanced NO2 but weakened NH3 sensing compared with bare RGO, showing promise in tuning the sensitivity and selectivity of RGO-based gas sensors.
TL;DR: In this paper, a large-scale randomized trial testing the efficacy of a family-school partnership model (i.e., conjoint behavioral consultation) for promoting behavioral competence and decrea...
Abstract: The present study is a large-scale randomized trial testing the efficacy of a family–school partnership model (i.e., conjoint behavioral consultation) for promoting behavioral competence and decrea...
TL;DR: In this article, three key intervals are evaluated using the concept of the equilibrium-line altitude (ELA) as a control on glaciation to provide insight into two intervals of paradoxical ice distribution during and following glaciation.
TL;DR: Inverse Compton cascades (ICC) initiated by energetic gamma rays (E {approx}> 100 GeV) enhance the GeV emission from bright, extragalactic TeV sources.
Abstract: Inverse Compton cascades (ICCs) initiated by energetic gamma rays (E {approx}> 100 GeV) enhance the GeV emission from bright, extragalactic TeV sources. The absence of this emission from bright TeV blazars has been used to constrain the intergalactic magnetic field (IGMF), and the stringent limits placed on the unresolved extragalactic gamma-ray background (EGRB) by Fermi have been used to argue against a large number of such objects at high redshifts. However, these are predicated on the assumption that inverse Compton scattering is the primary energy-loss mechanism for the ultrarelativistic pairs produced by the annihilation of the energetic gamma rays on extragalactic background light photons. Here, we show that for sufficiently bright TeV sources (isotropic-equivalent luminosities {approx}> 10{sup 42} erg s{sup -1}) plasma beam instabilities, specifically the 'oblique' instability, present a plausible mechanism by which the energy of these pairs can be dissipated locally, heating the intergalactic medium. Since these instabilities typically grow on timescales short in comparison to the inverse Compton cooling rate, they necessarily suppress the ICCs. As a consequence, this places a severe constraint on efforts to limit the IGMF from the lack of a discernible GeV bump in TeV sources. Similarly, it considerably weakens the Fermi limitsmore » on the evolution of blazar populations. Specifically, we construct a TeV-blazar luminosity function from those objects currently observed and find that it is very well described by the quasar luminosity function at z {approx} 0.1, shifted to lower luminosities and number densities, suggesting that both classes of sources are regulated by similar processes. Extending this relationship to higher redshifts, we show that the magnitude and shape of the EGRB above {approx}10 GeV are naturally reproduced with this particular example of a rapidly evolving TeV-blazar luminosity function.« less
TL;DR: In this paper, the activation of CO2 on defective surface of Cu(I)/TiO2-x has been studied using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).
Abstract: The activation of CO2 on defective surface of Cu(I)/TiO2–x has been studied using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). It was demonstrated that CO2– species, generated upon an electron attachment to CO2, are spontaneously dissociated into CO even in the dark on a partially oxygen depleted Cu(I)/TiO2–x surface prepared by thermal annealing in an inert environment. The formation of CO bound on Cu+ sites was identified in the DRIFT spectra, and isotopic carbon-labeling experiments confirmed that the produced CO was derived from CO2. The spontaneous dissociation of CO2– in the dark is to a large extent associated with the surface oxygen vacancies that provide not only the electronic charge (i.e., formation of Ti3+) but also the sites for the adsorption of oxygen atoms from CO2. The surface Cu+ species may facilitate destabilizing adsorbed CO2– and enhance its subsequent dissociation to CO. The defective surface is much more active than defect-free surface; the healed o...
TL;DR: Comprehensive behavior therapy is a safe and effective intervention for adults with Tourette syndrome and patients receiving behavior therapy who were available for assessment at 6 months after treatment showed continued benefit.
Abstract: Context Tics in Tourette syndrome begin in childhood, peak in early adolescence, and often decrease by early adulthood. However, some adult patients continue to have impairing tics. Medications for tics are often effective but can cause adverse effects. Behavior therapy may offer an alternative but has not been examined in a large-scale controlled trial in adults. Objective To test the efficacy of a comprehensive behavioral intervention for tics in adults with Tourette syndrome of at least moderate severity. Design A randomized controlled trial with posttreatment evaluations at 3 and 6 months for positive responders. Setting Three outpatient research clinics. Patients Patients (N = 122; 78 males; age range, 16-69 years) with Tourette syndrome or chronic tic disorder were recruited between December 27, 2005, and May 21, 2009. Interventions Patients received 8 sessions of comprehensive behavioral intervention for tics or 8 sessions of supportive treatment for 10 weeks. Patients with a positive response were given 3 monthly booster sessions. Main Outcome Measures Total tic score on the Yale Global Tic Severity Scale and the Clinical Global Impression–Improvement scale rated by a clinician masked to treatment assignment. Results Behavior therapy was associated with a significantly greater mean (SD) decrease on the Yale Global Tic Severity Scale (24.0 [6.47] to 17.8 [7.32]) from baseline to end point compared with the control treatment (21.8 [6.59] to 19.3 [7.40]) (P Conclusion Comprehensive behavior therapy is a safe and effective intervention for adults with Tourette syndrome. Trial Registration clinicaltrials.gov Identifier: NCT00231985
TL;DR: The study draws on the compliance theory and the general deterrence theory to propose a research model in which the relations among coercive control, remunerative control, which is generally missing in both research and practice; and certainty of control are studied.
Abstract: Companies' information security efforts are often threatened by employee negligence and insider breach. To deal with these insider issues, this study draws on the compliance theory and the general deterrence theory to propose a research model in which the relations among coercive control, which has been advocated by scholars and widely practiced by companies; remunerative control, which is generally missing in both research and practice; and certainty of control are studied. A Web-based field experiment involving real-world employees in their natural settings was used to empirically test the model. While lending further support to the general deterrence theory, our findings highlight that reward enforcement, a remunerative control mechanism in the information systems security context, could be an alternative for organizations where sanctions do not successfully prevent violation. The significant interactions between punishment and reward found in the study further indicate a need for a more comprehensive ...
TL;DR: A measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV is reported, derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory.
Abstract: We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of [505 +/- 22(stat)(-36)(+28)(syst)] mb is found.