bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light‐Activated, Multi‐Semiconductor Hybrid Microswimmers
Authors: O'Neel‐Judy Étude , Nicholls Dylan , Castañeda John , Gibbs John G. 
Published: July 2018

AbstractUsing a dynamic fabrication process, hybrid, photoactivated microswimmers made from two different semiconductors, titanium dioxide (TiO2) and cuprous oxide (Cu2O) are developed, where each material occupies a distinct portion of the multiconstituent particles. Structured light‐activated microswimmers made from only TiO2 or Cu2O are observed to be driven in hydrogen peroxide and water most vigorously under UV or blue light, respectively, whereas hybrid structures made from both of these materials exhibit wavelength‐dependent modes of motion due to the disparate responses of each photocatalyst. It is also found that the hybrid particles are activated in water alone, a behavior which is not observed in those made from a single semiconductor, and thus, the system may open up a new class of fuel‐free photoactive colloids that take advantage of semiconductor heterojunctions. The TiO2/Cu2O hybrid microswimmer presented here is but an example of a broader method for inducing different modes of motion in a single light‐activated particle, which is not limited to the specific geometries and materials presented in this study.
Zones of untreatable water pollution call for better appreciation of mitigation limits and opportunities
Authors: Destouni Georgia , Jarsjö Jerker 
Published: July 2018

This opinion piece addresses subsurface legacy sources and their role in mitigation of large‐scale water pollution and eutrophication. We provide a mechanistic theoretical basis and concrete data‐based exemplification of dominant contributions from such sources to total recipient loads. We specifically develop a diagnostic test to detect such contributions, recognizing that they are inaccessible and associated with long transport times that tend to evade detection when homogeneous catchment models are calibrated to typically heterogeneous catchments. Dominant legacy‐source contributions are also in practice untreatable within the commonly short time frames given for compliance with environmental regulation. We therefore argue that, for considerable water quality improvements to be achieved within such short time frames, mitigation measures need to be spatially differentiated and directed to (sub)catchments without major legacy sources. The presented diagnostic test identifies dominant prevalence of such sources where there is linear temporal correlation between the nutrient/pollutant loads and the water discharges from a (sub)catchment. Confidence in this identification may be strengthened by independent quantification of long transport times and records of temporally extended presence of nutrient/pollutant sources in the same (sub)catchment.This article is categorized under:
Science of Water > Water Quality
Engineering Water > Planning Water
Scattering of gravitational and electromagnetic waves off AdS2 × S2 in extreme Reissner-Nordstrom
Authors: Porfyriadis Achilleas P. 
Published: July 2018

AbstractThe direct product of two-dimensional anti-de Sitter spacetime with a two-sphere is an exact solution of four-dimensional Einstein-Maxwell theory without a cosmological constant. In this paper, we analytically solve the coupled gravitational and electromagnetic perturbation equations ofAdS2×S2in Einstein-Maxwell theory. On the other hand,AdS2×S2also describes the near-horizon region of the extreme Reissner-Nordstrom (ERN) black hole. We therefore also solve the connection problem: we show how theAdS2×S2perturbation equations arise from an appropriate near-horizon approximation of the corresponding equations for the ERN and then, using matched asymptotic expansions, we analytically extend theAdS2×S2solutions away from the near-horizon region connecting them with solutions in the far asymptotically flat region. From the point of view of ERN our results may be thought of as computing the classical scattering matrix for gravitational and electromagnetic waves which probe the near-horizon region of the black hole.
Child and adolescent sleep duration recommendations in relation to psychological and somatic complaints based on data between 1985 and 2013 from 11 to 15 year‐olds☆
Authors: Norell‐Clarke Annika , Hagquist Curt 
Published: July 2018

ABSTRACTPurposeTo investigate the association between sleep duration, sleep initiation difficulties and psychological and somatic complaints.MethodsWe used three cohorts of cross‐sectional Swedish questionnaire data, from the Health Behaviours of School aged Children (1985/1986, 2005/2006, 2013/2014, n=>18 000, aged 11–15). Specific complaints (e.g. pain) and total complaint load were used as outcomes of sleep duration, sleep initiation difficulties and the combination of them both.ResultsSleeping less than recommended and sleep initiation difficulties were associated with increased odds of specific complaints and belonging to the group with the greatest complaint load. The combination of short sleep duration and sleep initiation difficulties were associated with higher odds than either sleep issue alone. No interaction effects between time and sleep variables were found regarding complaints.ConclusionsThe findings support recent sleep duration recommendations. Further, sleep issues warrant a broad health assessment as they indicate a high likelihood of other complaints.
EXPLAINING ELECTIONS IN SINGAPORE: DOMINANT PARTY RESILIENCE AND VALENCE POLITICS
Authors: Oliver Steven , Ostwald Kai 
Published: July 2018

AbstractThe People's Action Party (PAP) of Singapore is one of the world's longest ruling dominant parties, having won every general election since the country's independence in 1965. Why do Singaporeans consistently vote for the PAP, contrary to the expectations of democratization theories? We argue that valence considerations—specifically, perceptions of party credibility—are the main factor in the voting behavior of Singapore's electorate, and are critical to explaining the PAP's resilience. Furthermore, we argue that the primacy of valence politics arose in part by design, as the PAP has used its control of Singapore's high-capacity state to reshape society and thereby reshape voter preferences towards its comparative advantages. We use a multi-methods approach to substantiate this argument, including a comprehensive quantitative analysis of recent elections. Ultimately, our findings suggest that a focus on valence politics can increase the resilience of dominant parties, but that such a strategy also faces natural limits.
Faunal overview of the Mud Hill locality from the early Permian Vale Formation of Taylor County, Texas
Authors: Gee Bryan M. , Rosscoe Steven J. , Scott Diane , Ostlien Judie , Reisz Robert R. 
Published: July 2018

AbstractThe Texas red beds represent one of the richest series of early Permian deposits in the world. In particular, the Clear Fork Group has produced a diverse assemblage of temnospondyls, early reptiles, and synapsids. However, most of this material has been sourced from the oldest member, the Arroyo Formation, and the understanding of the paleoecosystem of the younger Vale and Choza formations is less well resolved. Here we present a previously undescribed Vale locality, the first vertebrate-bearing locality from the formation to be described in detail in several decades, from near Abilene, Texas with juvenile diplocaulids, captorhinids, abundant material of rare taxa such asVaranopsand diadectids, and the first report of a recumbirostran ‘microsaur’ from the formation. This assemblage is atypical of early Permian deposits in the taxonomic and size distribution of the vertebrate fauna in comparison to other localities from the Vale Formation that preserve a greater abundance of aquatic taxa (e.g., fishes,Trimerorhachis) and synapsids (e.g.,Dimetrodon). Minimal abrasion of the elements, relative articulation and association of the specimen ofVaranops, and the paucity of aquatic taxa suggest an ephemeral pond deposit in which organisms were preserved essentially in situ. Our characterization of the locality also permits a revision and discussion of the vertebrate faunal assemblage of the Vale Formation.
VALUE AND PERFORMANCE OF ACCOUNTABLE CARE ORGANIZATIONS: A COST-MINIMIZATION ANALYSIS
Authors: Parasrampuria Sonal , Oakes Allison H. , Wu Shannon S. , Parikh Megha A. , Padula William V. 
Published: July 2018

Objectives:Determine the relationship between quality of an accountable care organization (ACO) and its long-term reduction in healthcare costs.Methods:We conducted a cost minimization analysis. Using Centers for Medicare and Medicaid cost and quality data, we calculated weighted composite quality scores for each ACO and organization-level cost savings. We used Markov modeling to compute the probability that an ACO transitioned between different quality levels in successive years. Considering a health-systems perspective with costs discounted at 3 percent, we conducted 10,000 Monte Carlo simulations to project long-term cost savings by quality level over a 10-year period. We compared the change in per-member expenditures of Pioneer (early-adopters) ACOs versus Medicare Shared Savings Program (MSSP) ACOs to assess the impact of coordination of care, the main mechanism for cost savings.Results:Overall, Pioneer ACOs saved USD 641.24 per beneficiary and MSSP ACOs saved USD 535.59 per beneficiary. By quality level: (a) high quality organizations saved the most money (Pioneer: USD 459; MSSP: USD 816); (b) medium quality saved some money (Pioneer: USD 222; MSSP: USD 105); and (c) low quality suffered financial losses (Pioneer: USD -40; MSSP: USD -386).Conclusions:Within the existing fee-for-service healthcare model, ACOs are a mechanism for decreasing costs by improving quality of care. Higher quality organizations incorporate greater levels of coordination of care, which is associated with greater cost savings. Pioneer ACOs have the highest level of integration of services; hence, they save the most money.
Hepatitis delta virus and hepatocellular carcinoma: an update
Authors: Romeo Raffaella , Petruzziello Arnolfo , Pecheur Eve Isabel , Facchetti Floriana , Perbellini Riccardo , Galmozzi Enrico , Khan Najeeb Ullah , Di Capua Lucia , Sabatino Rocco , Botti Gerardo , Loquercio Giovanna 
Published: July 2018

AbstractHepatitis delta virus (HDV) is a defective RNA virus that depends on the presence of hepatitis B virus (HBV) for the creation of new virions and propagation of the infection to hepatocytes. Chronic infection with HDV is usually associated with a worsening of HBV infection, leading more frequently to cirrhosis, increased risk of liver decompensation and hepatocellular carcinoma (HCC) occurrence. In spite of a progressive declining prevalence of both acute and chronic HDV infection observed over several years, mainly due to increased global health policies and mass vaccination against HBV, several European countries have more recently observed stable HDV prevalence mainly due to migrants from non-European countries. Persistent HDV replication has been widely demonstrated as associated with cirrhosis development and, as a consequence, development of liver decompensation and occurrence of HCC. Several treatment options have been attempted with poor results in terms of HDV eradication and improvement of long-term prognosis. A global effort is deemed urgent to enhance the models already existing as well as to learn more about HDV infection and correlated tumourigenesis mechanisms.
Insights Into Complex Subdecimeter Fracturing Processes Occurring During a Water Injection Experiment at Depth in Äspö Hard Rock Laboratory, Sweden
Authors: Kwiatek G. , Martínez‐Garzón P. , Plenkers K. , Leonhardt M. , Zang A. , von Specht S. , Dresen G. , Bohnhoff M. 
Published: July 2018

AbstractWe investigate the source characteristics of picoseismicity (Mw < −2) recorded during a hydraulic fracturing in situ experiment performed in the underground Äspö Hard Rock Laboratory, Sweden. The experiment consisted of six stimulations driven by three different water injection schemes and was performed inside a 28‐m‐long, horizontal borehole located at 410‐m depth. The fracturing processes were monitored with a variety of seismic networks including broadband seismometers, geophones, high‐frequency accelerometers, and acoustic emission sensors thereby covering a wide frequency band between 0.01 and 100,000 Hz. Here we study the high‐frequency signals with dominant frequencies exceeding 1000 Hz. The combined seismic network allowed for detection and detailed analysis of 196 small‐scale seismic events with moment magnitudes MW < −3.5 (source sizes of decimeter scale) that occurred solely during the stimulations and shortly after. The double‐difference relocated hypocenter catalog as well as source parameters were used to study the physical characteristics of the induced seismicity and then compared to the stimulation parameters. We observe a spatiotemporal migration of the picoseismic events away and toward the injection intervals in direct correlation with changes in the hydraulic energy (product of fluid injection pressure and injection rate). We find that the total radiated seismic energy is extremely low with respect to the product of injected fluid volume and pressure (hydraulic energy). The radiated seismic energy correlates well with the hydraulic energy rate. The obtained fault plane solutions for particularly well‐characterized events signify the reactivation of preexisting rock defects under influence of increased pore fluid pressure on fault plane orientations in good correspondence with the local stress field orientation.
Controls on Millennial‐Scale Atmospheric CO2 Variability During the Last Glacial Period
Authors: Bauska T. K. , Brook E. J. , Marcott S. A. , Baggenstos D. , Shackleton S. , Severinghaus J. P. , Petrenko V. V. 
Published: July 2018

AbstractChanges in atmospheric CO2 on millennial‐to‐centennial timescales are key components of past climate variability during the last glacial and deglacial periods (70–10 ka), yet the sources and mechanisms responsible for the CO2 fluctuations remain largely obscure. Here we report the 13C/12C ratio of atmospheric CO2 during a key interval of the last glacial period at submillennial resolution, with coeval histories of atmospheric CO2, CH4, and N2O concentrations. The carbon isotope data suggest that the millennial‐scale CO2 variability in Marine Isotope Stage 3 is driven largely by changes in the organic carbon cycle, most likely by sequestration of respired carbon in the deep ocean. Centennial‐scale CO2 variations, distinguished by carbon isotope signatures, are associated with both abrupt hydrological change in the tropics (e.g., Heinrich events) and rapid increases in Northern Hemisphere temperature (Dansgaard‐Oeschger events). These events can be linked to modes of variability during the last deglaciation, thus suggesting that drivers of millennial and centennial CO2 variability during both periods are intimately linked to abrupt climate variability.
Ion‐Scale Kinetic Alfvén Turbulence: MMS Measurements of the Alfvén Ratio in the Magnetosheath
Authors: Roberts O. W. , Toledo‐Redondo S. , Perrone D. , Zhao J. , Narita Y. , Gershman D. , Nakamura R. , Lavraud B. , Escoubet C. P. , Giles B. , Dorelli J. , Pollock C. , Burch J. 
Published: July 2018

AbstractTurbulence in the Earth's magnetosheath at ion kinetic scales is investigated with the magnetospheric multiscale spacecraft. Several possibilities in the wave paradigm have been invoked to explain plasma turbulence at ion kinetic scales such as kinetic Alfvén, slow, or magnetosonic waves. To differentiate between these different plasma waves is a challenging task, especially since some waves, in particular, kinetic slow waves and kinetic Alfvén waves, share some properties making the possibility to distinguishing between them very difficult. Using the excellent time resolution data set provided from both the fluxgate magnetometer and the Fast Plasma Instrument, the ratio of trace velocity fluctuations to the magnetic fluctuations (in Alfvén units), which is termed the Alfvén ratio, can be calculated down to ion kinetic scales. Comparison of the measured Alfvén ratio is performed with respect to the expectation from two‐fluid magnetohydrodynamic theory for the kinetic slow wave and kinetic Alfvén wave. Moreover, the plasma data also allow normalized fluctuation amplitudes of density and magnetic field to be compared differentiating between magnetosonic‐like and kinetic Alfvén‐like turbulence. Using these two different ratios, we can rule out that the fluctuations at ion scales are dominated by magnetosonic‐like fluctuations or kinetic slow‐like fluctuations and show that they are consistent with kinetic Alfvén‐like fluctuations. This suggests that in the wave paradigm, heating in the direction of the parallel magnetic field is predominantly by the Landau damping of the kinetic Alfvén wave.
Wetlandscape Fractal Topography
Authors: Bertassello Leonardo E. , Rao P. Suresh C. , Jawitz James W. , Botter Gianluca , Le Phong V. V. , Kumar Praveen , Aubeneau Antoine F. 
Published: July 2018

AbstractNatural wetlands are ecological, biogeochemical, and hydrological hot spots yet continue to disappear under human pressure. Their shapes and sizes control their hydroecological functions. We propose that elevation data can be used to delineate potential wetlands and that the (statistical) distributions of potential wetlands should be identical to the distributions of actual wetlands. We compare the shape and size distributions of wetlands reported in the National Wetland Inventory with those of potential wetlands identified using a topographic depression identification model. We estimated area and perimeter distributions as well as shoreline fractal dimension in six contrasting locations in the United States. Pareto distributions described the tails of these distributions, with similar slopes for both model and data. The shape of shorelines was also similar, and their fractal dimension clustered aroundD = 4/3, a pervasive value in nature. We also analyzed the entire wetland inventory data set for the conterminous United States (~20 million wetlands) for reference and found the statistics to be invariant across scales. Our results demonstrate that a simple topographic model can identify most reported wetlands as well as potential wetlands missing from the inventory. These findings could inform strategic surveys and the conservation of wetlandscapes.
Mapping H3+ Temperatures in Jupiter's Northern Auroral Ionosphere Using VLT‐CRIRES
Authors: Johnson R. E. , Melin H. , Stallard T. S. , Tao C. , Nichols J. D. , Chowdhury M. N. 
Published: July 2018

AbstractWe present a detailed study of the H3+ auroral emissions at Jupiter, using data taken on 31 December 2012 with the long‐slit Echelle spectrometer CRIRES (ESO‐VLT). From this data set the rotational temperature of the H3+ ions in Jupiter's upper atmosphere was calculated using the ratio of the ν2 Q(1,0−) and ν2 Q(3,0−) fundamental emission lines. The entire northern auroral region was observed, providing a highly detailed view of ionospheric temperatures, which were mapped onto polar projections. The temperature range we derive in the northern auroral region is ~750–1000 K, which is consistent with past studies, although the temperature structure differs. We identify two broad regions which exhibit temperature changes over a short period of time (~80 minutes). We propose that the changes in temperature could be due to a local time change in particle precipitation energy, or they could be caused by dynamic temperature changes generated in the neutral thermosphere due to the magnetospheric response to a transient enhancement of solar wind dynamic pressure, as predicted by models. By comparing the H3+ temperature, column density, total emission, and line‐of‐sight velocity, we were unable to identify a single dominant mechanism responsible for the energetics in Jupiter's northern auroral region. The comparison reveals that there is complex interplay between heating by impact from particle precipitation and Joule heating, as well as cooling by the H3+ thermostat effect.
Perchlorate‐Driven Combustion of Organic Matter During Pyrolysis‐Gas Chromatography‐Mass Spectrometry: Implications for Organic Matter Detection on Earth and Mars
Authors: Royle Samuel H. , Oberlin Elizabeth , Watson Jonathan S. , Montgomery Wren , Kounaves Samuel P. , Sephton Mark A. 
Published: July 2018

AbstractThe search for life on Mars targets the detection of organic matter from extant or extinct organisms. Current protocols use thermal extraction procedures to transfer organic matter to mass spectrometer detectors. Oxidizing minerals on Mars, such as perchlorate, interfere with organic detection by thermal extraction. Thermal decomposition of perchlorate releases oxygen, which promotes combustion of organic carbon. We have assessed the minimum mass ratio of organic carbon to perchlorate required to detect organic matter by thermal extraction and mass spectrometry. Locations on Mars with organic carbon to perchlorate ratios above 4.7–9.6 should be targeted. Because habitability is enhanced by the presence of liquid water and because perchlorate is a water‐soluble salt, locations on Mars with evidence of past or recent liquid water are high priority targets.
Water-dispersible PEG-curcumin/amine-functionalized covalent organic framework nanocomposites as smart carriers for in vivo drug delivery
Authors: Zhang Guiyang , Li Xinle , Liao Qiaobo , Liu Yanfeng , Xi Kai , Huang Wenyu , Jia Xudong 
Published: July 2018

AbstractCovalent organic frameworks (COFs) as drug-delivery carriers have been mostly evaluated in vitro due to the lack of COFs nanocarriers that are suitable for in vivo studies. Here we develop a series of water-dispersible polymer-COF nanocomposites through the assembly of polyethylene-glycol-modified monofunctional curcumin derivatives (PEG-CCM) and amine-functionalized COFs (APTES-COF-1) for in vitro and in vivo drug delivery. The real-time fluorescence response shows efficient tracking of the COF-based materials upon cellular uptake and anticancer drug (doxorubicin (DOX)) release. Notably, in vitro and in vivo studies demonstrate that PEG-CCM@APTES-COF-1 is a smart carrier for drug delivery with superior stability, intrinsic biodegradability, high DOX loading capacity, strong and stable fluorescence, prolonged circulation time and improved drug accumulation in tumors. More intriguingly, PEG350-CCM@APTES-COF-1 presents an effective targeting strategy for brain research. We envisage that PEG-CCM@APTES-COF-1 nanocomposites represent a great promise toward the development of a multifunctional platform for cancer-targeted in vivo drug delivery.
Creating two self-assembly micro-environments to achieve supercrystals with dual structures using polyhedral nanoparticles
Authors: Lee Yih Hong , Lay Chee Leng , Shi Wenxiong , Lee Hiang Kwee , Yang Yijie , Li Shuzhou , Ling Xing Yi 
Published: July 2018

AbstractOrganizing nanoparticles into supercrystals comprising multiple structures remains challenging. Here, we achieve one assembly with dual structures for Ag polyhedral building blocks, comprising truncated cubes, cuboctahedra, truncated octahedra, and octahedra. We create two micro-environments in a solvent evaporation-driven assembly system: one at the drying front and one at the air/water interface. Dynamic solvent flow concentrates the polyhedra at the drying front, generating hard particle behaviors and leading to morphology-dependent densest-packed bulk supercrystals. In addition, monolayers of nanoparticles adsorb at the air/liquid interface to minimize the air/liquid interfacial energy. Subsequent solvent evaporation gives rise to various structurally diverse dual-structure supercrystals. The topmost monolayers feature distinct open crystal structures with significantly lower packing densities than their densest-packed supercrystals. We further highlight a 3.3-fold synergistic enhancement of surface-enhanced Raman scattering efficiency arising from these dual-structure supercrystals as compared to a uniform one.