bluuebunny/crossref_metadata_2025 huggingface dataset:
A Match-based approach to the estimation of polar stratospheric ozone loss using Aura Microwave Limb Sounder observations
Authors: Livesey N. J. , Santee M. L. , Manney G. L.
Published: September 2015

Abstract. The well-established "Match" approach to quantifying chemical destruction of ozone in the polar lower stratosphere is applied to ozone observations from the Microwave Limb Sounder (MLS) on NASA's Aura spacecraft. Quantification of ozone loss requires distinguishing transport- and chemically induced changes in ozone abundance. This is accomplished in the Match approach by examining cases where trajectories indicate that the same air mass has been observed on multiple occasions. The method was pioneered using ozonesonde observations, for which hundreds of matched ozone observations per winter are typically available. The dense coverage of the MLS measurements, particularly at polar latitudes, allows matches to be made to thousands of observations each day. This study is enabled by recently developed MLS Lagrangian trajectory diagnostic (LTD) support products. Sensitivity studies indicate that the largest influence on the ozone loss estimates are the value of potential vorticity (PV) used to define the edge of the polar vortex (within which matched observations must lie) and the degree to which the PV of an air mass is allowed to vary between matched observations. Applying Match calculations to MLS observations of nitrous oxide, a long-lived tracer whose expected rate of change is negligible on the weekly to monthly timescales considered here, enables quantification of the impact of transport errors on the Match-based ozone loss estimates. Our loss estimates are generally in agreement with previous estimates for selected Arctic winters, though indicating smaller losses than many other studies. Arctic ozone losses are greatest during the 2010/11 winter, as seen in prior studies, with 2.0 ppmv (parts per million by volume) loss estimated at 450 K potential temperature (~ 18 km altitude). As expected, Antarctic winter ozone losses are consistently greater than those for the Arctic, with less interannual variability (e.g., ranging between 2.3 and 3.0 ppmv at 450 K). This study exemplifies the insights into atmospheric processes that can be obtained by applying the Match methodology to a densely sampled observation record such as that from Aura MLS.
The effect of assimilating satellite derived soil moisture in SiBCASA on simulated carbon fluxes in Boreal Eurasia
Authors: van der Molen M. K. , de Jeu R. A. M. , Wagner W. , van der Velde I. R. , Kolari P. , Kurbatova J. , Varlagin A. , Maximov T. C. , Kononov A. V. , Ohta T. , Kotani A. , Krol M. C. , Peters W.
Published: September 2015

Abstract. Boreal Eurasia is a region where the interaction between droughts and the carbon cycle may have significant impacts on the global carbon cycle. Yet the region is extremely data sparse with respect to meteorology, soil moisture and carbon fluxes as compared to e.g. Europe. To better constrain our vegetation model SiBCASA, we increase data usage by assimilating two streams of satellite derived soil moisture. We study if the assimilation improved SiBCASA's soil moisture and its effect on the simulated carbon fluxes. By comparing to unique in situ soil moisture observations, we show that the passive microwave soil moisture product did not improve the soil moisture simulated by SiBCASA, but the active data seem promising in some aspects. The match between SiBCASA and ASCAT soil moisture is best in the summer months over low vegetation. Nevertheless, ASCAT failed to detect the major droughts occurring between 2007 and 2013. The performance of ASCAT soil moisture seems to be particularly sensitive to ponding, rather than to biomass. The effect on the simulated carbon fluxes is large, 5–10% on annual GPP and TER, and tens of percent on local NEE, and 2% on area-integrated NEE, which is the same order of magnitude as the inter-annual variations. Consequently, this study shows that assimilation of satellite derived soil moisture has potentially large impacts, while at the same time further research is needed to understand under which conditions the satellite derived soil moisture improves the simulated soil moisture.
HydroSCAPE: a multi-scale framework for streamflow routing in large-scale hydrological models
Authors: Piccolroaz S. , Di Lazzaro M. , Zarlenga A. , Majone B. , Bellin A. , Fiori A.
Published: September 2015

Abstract. We present HydroSCAPE, a large scale hydrological model with an innovative streamflow routing scheme based on the Width Function Instantaneous Unit Hydrograph (WFIUH) theory, which is designed to facilitate coupling with weather forecasting and climate models. HydroSCAPE preserves geomorphological dispersion of the river network when dealing with horizontal hydrological fluxes, irrespective of the adopted grid size, which is typically inherited from the overlaying weather forecast or climate model. This is achieved through a separate treatment of hillslope processes and routing within the river network, with the latter simulated by suitable transfer functions constructed by applying the WFIUH theory to the desired level of detail. Transfer functions are constructed for each grid cell and nodes of the network where water discharge is desired by taking advantage of the detailed morphological information contained in the Digital Elevation Model of the zone of interest. These characteristics render HydroSCAPE well suited for multi-scale applications, ranging from catchment up to continental scale, and to investigate extreme events (e.g. floods) that require an accurate description of routing through the river network. The model enjoys reliability and robustness, united to parsimony in the adopted parametrization and computational efficiency, leading to a dramatic reduction of the computational effort with respect to full-gridded models at comparable level of accuracy of routing. Additionally, HydroSCAPE is designed with a simple and flexible modular structure, which makes it particularly suitable to massive parallelization, customization according to the specific user needs and preferences (e.g. choice of rainfall-runoff model), and continuous development and improvements.
Strong ground motion prediction for southwestern China from small earthquake records
Authors: Tao Z. R. , Tao X. X. , Cui A. P.
Published: September 2015

Abstract. For regions lack of strong ground motion records, a method is developed to predict strong ground motion by small earthquake records from local broadband digital earthquake networks. Sichuan and Yunnan regions, located in southwestern China, are selected as the targets. Five regional source and crustal medium parameters are inversed by micro-Genetic Algorithm. These parameters are adopted to predict strong ground motion for moment magnitude (Mw) 5.0, 6.0 and 7.0. Strong ground motion data are compared with the results, most of the result pass through ideally the data point plexus, except the case of Mw 7.0 in Sichuan region, which shows an obvious slow attenuation. For further application, this result is adopted in probability seismic hazard assessment (PSHA) and near-field strong ground motion synthesis of the Wenchuan Earthquake.
Dual plane PIV investigation of acoustically excited jets in a swirl nozzle
Authors: Regunath G. S. , Zimmerman W. B. , Rees J. M.
Published: September 2015

Abstract. A novel dual-plane dye laser PIV technique used to analyze helicity and energy dissipation in an unexcited turbulent swirling jet of pressurized cold air has established that regions within the flow field of the jet exhibiting high helicity are correlated with regions of high turbulent kinetic energy dissipation. This PIV configuration provides estimates of all components of the velocity gradient tensor, facilitating calculation of the helicity from the vorticity components. Application of this novel dual-plane PIV technique is extended in this study to investigate helical structures in a turbulent swirling jet where the underlying shear flow is subjected to external acoustic sinusoidal forcing in a plane perpendicular to the central axis of the jet. It was found that acoustic excitation had a significant effect on the mean velocity profile parallel to the direction of the jet. The horizontal forcing resulted in the generation of vorticity that was skewed with a pitch that favored a distribution of angles around 90° with respect to the velocity vector. The distribution of the time-averaged helicity angle indicated organized helical activity, but such activity is not dominated by large-scale coherent structures of maximal helicity.
Improving semi-automated glacier mapping with a multi-method approach: applications in central Asia
Authors: Smith T. , Bookhagen B. , Cannon F.
Published: September 2015

Abstract. Studies of glaciers generally require precise glacier outlines. Where these are not available, extensive manual digitization in a geographic information system (GIS) must be performed, as current algorithms struggle to delineate glacier areas with debris cover or other irregular spectral profiles. Although several approaches have improved upon spectral band ratio delineation of glacier areas, none have entered wide use due to complexity or computational intensity. In this study, we present and apply a glacier mapping algorithm in Central Asia which delineates both clean glacier ice and debris-covered glacier tongues. The algorithm is built around the unique velocity and topographic characteristics of glaciers and further leverages spectral and spatial relationship data. We found that the algorithm misclassifies between 2 and 10 % of glacier areas, as compared to a ~ 750 glacier control data set, and can reliably classify a given Landsat scene in 3–5 min. The algorithm does not completely solve the difficulties inherent in classifying glacier areas from remotely sensed imagery but does represent a significant improvement over purely spectral-based classification schemes, such as the band ratio of Landsat 7 bands three and five or the normalized difference snow index. The main caveats of the algorithm are (1) classification errors at an individual glacier level, (2) reliance on manual intervention to separate connected glacier areas, and (3) dependence on fidelity of the input Landsat data.
Improved GRACE regional mass balance estimates of the Greenland Ice Sheet cross-validated with the input-output method
Authors: Xu Z. , Schrama E. , van der Wal W. , van den Broeke M. , Enderlin E. M.
Published: September 2015

Abstract. In this study, we use satellite gravimetry data from the Gravity Recovery and Climate Experiment (GRACE) to estimate regional mass changes of the Greenland ice sheet (GrIS) and neighbouring glaciated regions using a least-squares inversion approach. We also consider results from the input-output method (IOM) that quantifies the difference between mass input and output of the surface mass balance (SMB) components from the Regional Atmospheric Climate Model version 2 (RACMO2) and ice discharge (D) from 12 years of high-precision ice velocity and thickness surveys. We use a simulation model to quantify and correct for GRACE approximation errors in mass changes between different sub-regions of GrIS and investigate the reliability of pre-1990s ice discharge estimates based on modelled runoff. We find that the difference between IOM and our improved GRACE mass change estimates is reduced in terms of the long-term mass changes when using runoff-based discharge estimates in several sub-areas. In most regions our GRACE and IOM solutions are consistent with other studies, but differences remain in the northwestern GrIS. We verify the GRACE mass balance in that region by considering several different GIA models and mass change estimates derived from the Ice, Cloud and land Elevation satellite (ICEsat). We conclude that the remaining differences between GRACE and IOM are likely due to underestimated uncertainties in the IOM solutions.
CORRELATION OF FILLER NETWORKING WITH REINFORCEMENT AND DYNAMIC PROPERTIES OF SSBR/CARBON BLACK/SILICA COMPOSITES
Authors: Feng Wengjiang , Tang Zhenghai , Weng Peijin , Guo Baochun
Published: September 2015

The use of silica to partially replace carbon black is a common practice in the fabrication of “green tires.” Although some degree of consensus has been approached concerning the improved performance conferred by silica substitution, such as the improved dispersion of carbon black, a quantitative understanding of the relationship between filler networking and the performance of rubber composites has not been established. Thus, an investigation focusing on filler network structure and the correlation between the network structure and the reinforcement of rubber composites was conducted. We prepared solution-polymerized styrene–butadiene rubber (SSBR) reinforced by carbon black and carbon black/silica in different ratios. To exclude as much of the effect from changed crosslinking, and figure out how filler blending influences filler dispersion and filler network structure, the silane generally used in the tire industry was not adopted. The quantitative predictor, the mass fractal dimension df, was derived from the Kraus model and the Huber–Vilgis model. We found that when the amount of substituted silica increases, the filler cluster branching decreases, accompanied by increased reinforcement efficiency. The depressed filler networking induced by silica substitution at an appropriate proportion leads to improved dynamic properties, including lower rolling resistance and better wet skid. When the silica proportion in the filler is too high, severe filler networking is observed, resulting in decreased reinforcing efficiency and impaired dynamic properties.
La innovación en los procesos de provisión de personal: una perspectiva para la gestión del talento humano en las organizaciones
Authors: Paz Subillaga Alfredo Augusto , Núñez Rafael
Published: September 2015

Dentro del proceso de provisión de personal en el área de recursos humanos ha existido siempre un rechazo generalizado a poder manejar indicadores macroeconómicos con enfoque laboral, razón por la cual se desarrolló el presente estudio, puesto que existe la necesidad de indicar esa importancia y además demostrar el conocimiento que tienen los gestores del área de recursos humanos en este tema, aplicándolo a un proceso de provisión de personal por medio de la oferta laboral.En este sentido, es imperante que la preocupación por enlazar estas variables, es decir, los recursos humanos y los indicadores macroeconómicos sea latente, pues en el estadio de la gestión de las personas que trabajan en un área tan importante como la mencionada, deben tener sus parámetros de acción, de modo que estos puedan servir como base para la toma de decisiones importantes para tener al mejor talento humano dentro de las organizaciones y así lograr los objetivos trazados.El objetivo de la investigación es demostrar la importancia que tiene la provisión de personal, la innovación de sus procesos y los indicadores macroeconómicos laborales en la oferta laboral en un proceso de provisión de personal. Es una investigación de carácter descriptivo y muestra en sus principales resultados que la innovación y el conocimiento de las variables tratadas en los gestores de recursos humanos en las empresas metalmecánicas son aspectos que pueden ayudar a mejorar el proceso de provisión.Esta investigación es de tipo cuantitativa con propósito descriptivo, en la cual se consideró la muestra total de 16 gerentes de recursos humanos de empresas metalmecánicas, consideradas grandes, que cuentan con más de mil empleados en la Ciudad de Guatemala.Entre las conclusiones más importantes de esta investigación están que la innovación en los procesos de recursos humanos debe ser entendida como un valor agregado; cuando factores macroeconómicos y microeconómicos se cruzan con los objetivos de una organización, es cuando la gestión de los recursos humanos debe estar alineada de manera estratégica y no debe ser ajeno para los administradores de recursos humanos, manejar aspectos macroeconómicos, pues dentro de la estrategia y la gestión propia de la administración de este rubro debe existir un interés y una conciencia del impacto que pueda causar la información y estadísticas de este tipo en la empresa.Revista Portal de la Ciencia, No. 7, diciembre 2014; 65-76
Learning about Functions through Learner-Generated Examples
Authors: Dinkelman Martha O. , Cavey Laurie O.
Published: September 2015

In an introductory algebra course, LGEs engage students in writing about mathematics and can be used as a formative assessment tool.
Exploring New Geometric Worlds
Authors: Nirode Wayne
Published: September 2015

Familiar sets of points defined by distances appear as unexpected shapes in larger-distance geometry.
Virtual Miniature Golf
Authors: Edwards Michael Todd , Quinlan James
Published: September 2015

Current standards place significant emphasis on transformations in school geometry: “Fundamental are the rigid motions: translations, rotations, reflections, and combinations of these,” and “dynamic geometry environments provide students with experimental and modeling tools that allow them to investigate geometric phenomena” (CCSSI, 2010, p. 74). With these aims in mind, we share a favorite classroom activity—virtual miniature golf. Building on the work of Coxford and Usiskin (1991) and Powell et al. (1994), this activity provides geometry students with a real-world context for exploring reflection and reflection composition in technology-rich settings.
Making the Most of Going over Homework
Authors: Otten Samuel , Cirillo Michelle , Herbel-Eisenmann Beth A.
Published: September 2015

Reconsider typical discourse strategies when discussing homework and move toward a system that promotes the Standards for Mathematical Practice.
Board Game Frenzy
Authors: Simpson Amber , Monroe Jodi , Raquet Janel
Published: September 2015

What is your favorite board game? The problems below are based on popular games that can be played at home, within your classroom, or as part of family math nights at your school. We encourage you to send these problems home with students to promote mathematics learning with family members and peers outside the classroom. We recognize that these games may not be available in every classroom; you may want to display game board images on an interactive whiteboard in the classroom and as handouts for students to take home.
The Richness of Children's Fraction Strategies
Authors: Kent Laura B. , Empson Susan B. , Nielsen Lynne
Published: September 2015

Fifth graders explore approaches to solving a division-of-fractions problem introduced within the context of hot chocolate servings.
Designing a Children's Recreation Room
Authors: Lee Mi Yeon
Published: September 2015

Through this project-based unit, students engage in STEM fields by doing research and finding solutions to a real-world problem as an interior designer who is consulted to plan a children's recreation room. iSTEM (Integrating Science Technology Engineering in Mathematics) authors share ideas and activities that stimulate student interest in the integrated fields of science, technology, engineering, and mathematics (STEM) in K–grade 6 classrooms.
Point‐of‐care HIV early infant diagnosis: is test sensitivity everything?
Authors: Dunning Lorna , Hsiao Nei‐yuan , Myer Landon
Published: September 2015

Despite improvements in PMTCT services in low‐ and middle‐income countries, there are still almost 200,000 new paediatric HIV infections annually in sub‐Saharan Africa. This has led to early infant HIV diagnosis (EID) programmes becoming a public health priority, but until recently, EID has required specialist laboratory equipment and trained personnel which is only feasible in urban, centralized facilities. It is thought that the successful implementation of a point‐of‐care (POC) test for EID has the potential to increase access to virological tests and address some of the barriers regarding retention of infants in care. However, POC evaluation has not integrated focus on performance characteristics with the health systems issues surrounding the adoption of and optimum use of these new technologies. We propose that moderate improvements in linkage to care can more than offset suboptimal sensitivity of a POC EID test which could be critical in adjusting the focus for EID programme management away from test performance and towards their ability to facilitate successful linkage to antiretroviral therapy (ART) services. These findings also highlight the urgent need to explore the implementation and operational aspects of emerging POC tests in order to fully realize the potential benefits of new technologies in practice.
The many mysteries of Homo naledi
Authors: Stringer Chris
Published: September 2015

More than 1500 fossils from the Rising Star cave system in South Africa have been assigned to a new human species, Homo naledi, which displays a unique combination of primitive and derived traits throughout the skeleton.
Unix Survival Guide
Authors: Stein Lincoln D.
Published: September 2015

Most bioinformatics software has been designed to run on Linux and other Unix‐like systems. Unix is different from most desktop operating systems because it makes extensive use of a text‐only command‐line interface. It can be a challenge to become familiar with the command line, but once a person becomes used to it, there are significant rewards, such as the ability to string a commonly used series of commands together with a script. This appendix will get you started with the command line and other Unix essentials. © 2015 by John Wiley & Sons, Inc.
Delayed dynamic triggering of deep tremor along the Parkfield‐Cholame section of the San Andreas Fault following the 2014 M6.0 South Napa earthquake
Authors: Peng Zhigang , Shelly David R. , Ellsworth William L.
Published: September 2015

Large, distant earthquakes are known to trigger deep tectonic tremor along the San Andreas Fault and in subduction zones. However, there are relatively few observations of triggering from regional distance earthquakes. Here we show that a small tremor episode about 12–18 km NW of Parkfield was triggered during and immediately following the passage of surface waves from the 2014 Mw 6.0 South Napa main shock. More notably, a major tremor episode followed, beginning about 12 h later, and centered SE of Parkfield near Cholame. This major episode is one of the largest seen over the past several years, containing intense activity for ~3 days and taking more than 3 weeks to return to background levels. This episode showed systematic along‐strike migration at ~5 km/d, suggesting that it was driven by a slow‐slip event. Our results suggest that moderate‐size earthquakes are capable of triggering major tremor and deep slow slip at regional distances.
An M component with a concurrent dart leader traveling along different paths during a lightning flash
Authors: Stolzenburg M. , Marshall T. C. , Karunarathne S. , Karunarathna N. , Orville R. E.
Published: September 2015

Utilizing time‐correlated high‐speed video and electric field change data, a seven‐stroke lightning flash is described in which the fifth return stroke (RS) occurs 0.80 ms after the fourth RS connects to a different ground location 3.3 km away. The fifth RS is 0.34 ms after an M component starts down the different channel. The fifth stroke involves a dart leader traveling concurrently, though slower than the M component, in a prior channel to ground. There was no indication of leader advance along this path earlier during the fourth RS. The fourth stroke involves a stepped leader that started from the end of an observed prior dart leader branch which did not previously propagate to ground. The concurrent M component and dart leader are preceded by an in‐cloud event evidenced by a large‐amplitude, fast electric field change pulse, at 6.1 km estimated altitude, inferred as the connection to the channel for the M component. The M component current apparently initiates the dart leader about 40 µs later. A visible channel length of 10,400 m allows for the 2‐D propagation speed of the M component luminosity to be estimated in the range of 1.0 to 1.2 × 108 m s−1. The concurrent dart leader travels a visible length of 3445 m with 2‐D speed of 1.7 × 107 m s−1, similar to other dart leaders in this flash. Luminosity evolution along the channel through the RS and M component is also described. Estimated optical risetimes of three separate M components are 80–200 µs at 520 m above ground.
Effect of ions on sulfuric acid‐water binary particle formation: 2. Experimental data and comparison with QC‐normalized classical nucleation theory
Authors: Duplissy J. , Merikanto J. , Franchin A. , Tsagkogeorgas G. , Kangasluoma J. , Wimmer D. , Vuollekoski H. , Schobesberger S. , Lehtipalo K. , Flagan R. C. , Brus D. , Donahue N. M. , Vehkamäki H. , Almeida J. , Amorim A. , Barmet P. , Bianchi F. , Breitenlechner M. , Dunne E. M. , Guida R. , Henschel H. , Junninen H. , Kirkby J. , Kürten A. , Kupc A. , Määttänen A. , Makhmutov V. , Mathot S. , Nieminen T. , Onnela A. , Praplan A. P. , Riccobono F. , Rondo L. , Steiner G. , Tome A. , Walther H. , Baltensperger U. , Carslaw K. S. , Dommen J. , Hansel A. , Petäjä T. , Sipilä M. , Stratmann F. , Vrtala A. , Wagner P. E. , Worsnop D. R. , Curtius J. , Kulmala M.
Published: September 2015

We report comprehensive, demonstrably contaminant‐free measurements of binary particle formation rates by sulfuric acid and water for neutral and ion‐induced pathways conducted in the European Organization for Nuclear Research Cosmics Leaving Outdoor Droplets chamber. The recently developed Atmospheric Pressure interface‐time of flight‐mass spectrometer was used to detect contaminants in charged clusters and to identify runs free of any contaminants. Four parameters were varied to cover ambient conditions: sulfuric acid concentration (105 to 109 mol cm−3), relative humidity (11% to 58%), temperature (207 K to 299 K), and total ion concentration (0 to 6800 ions cm−3). Formation rates were directly measured with novel instruments at sizes close to the critical cluster size (mobility size of 1.3 nm to 3.2 nm). We compare our results with predictions from Classical Nucleation Theory normalized by Quantum Chemical calculation (QC‐normalized CNT), which is described in a companion paper. The formation rates predicted by the QC‐normalized CNT were extended from critical cluster sizes to measured sizes using the UHMA2 sectional particle microphysics model. Our results show, for the first time, good agreement between predicted and measured particle formation rates for the binary (neutral and ion‐induced) sulfuric acid‐water system. Formation rates increase with RH, sulfuric acid, and ion concentrations and decrease with temperature at fixed RH and sulfuric acid concentration. Under atmospheric conditions, neutral particle formation dominates at low temperatures, while ion‐induced particle formation dominates at higher temperatures. The good agreement between the theory and our comprehensive data set gives confidence in using the QC‐normalized CNT as a powerful tool to study neutral and ion‐induced binary particle formation in atmospheric modeling.
Controls on nitrous oxide production and consumption in reservoirs of the Ohio River Basin
Authors: Beaulieu Jake J. , Nietch Christopher T. , Young Jade L.
Published: September 2015

Aquatic ecosystems are a globally significant source of nitrous oxide (N2O), a potent greenhouse gas, but estimates are largely based on studies conducted in streams and rivers with relatively less known about N2O dynamics in reservoirs. Due to long water residence times and high nitrogen (N) loading rates, reservoirs support substantial N processing and therefore may be particularly important sites of N2O production. Predicting N2O emissions from reservoirs is difficult due to complex interactions between microbial N processing in the oxygen‐poor hypolimnion and oxygen‐rich epilimnion. Here we present the results of a survey of N2O depth profiles in 20 reservoirs draining a broad range of land use conditions in four states in the U.S. Nitrous oxide was supersaturated in the epilimnion of 80% of the reservoirs and was undersaturated in only one, indicating that reservoirs in this region are generally a source of N2O to the atmosphere. Nitrous oxide was undersaturated in the hypolimnion of 10 reservoirs, supersaturated in 9, and transitioned from supersaturation to undersaturation in 1 reservoir that was monitored periodically from midsummer to fall. All reservoirs with a mean hypolimnion nitrate concentration less than 50 µg N L−1 showed evidence of net N2O consumption in the hypolimnion. All reservoirs sampled during lake turnover supported N2O production throughout the water column. These results indicate that N2O dynamics in reservoirs differ widely both among systems and through time but can be predicted based on N and oxygen availability and degree of thermal stratification.
Novel Effective Approach for the Fabrication of PDMS‐Based Elastic Volume Gratings
Authors: Ryabchun Alexander , Wegener Michael , Gritsai Yuri , Sakhno Oksana
Published: September 2015

All‐optical fabrication of elastic volume diffraction gratings in polydimethylsiloxane (PDMS) is presented. Novel material based on the commercially available PDMS with incorporated benzophenone (BPh) photoactive molecules is developed. The gratings are formed by a holographic technique and UV irradiation through an amplitude mask. New material permits to obtain efficient volume gratings with periods ranging from hundreds nanometers to dozens of micrometers in elastic films of different thicknesses. Besides symmetric transmission 1D gratings, slanted and 2D gratings have been fabricated as well. Photoattachment of BPh molecules and their real‐time diffusion within elastic PDMS matrix in accordance with the spatially modulated light is considered as a mechanism of the gratings formation. The refractive index modulation amplitude of about 7.0 × 10−4 is achieved. It is shown that mechanical strain of the elastic volume gratings allows fully reproducible alteration of the gratings parameters. In order to tune the diffracted wavelength over the whole visible spectral range (from 410 up to 700 nm), a strain of about 75% is required. New volume diffraction PDMS gratings represent very successful combination of cheap and widely known materials with one‐step optical fabrication techniques providing high‐performance tunable diffraction elements that can be applied in photonics, sensing, and spectroscopy.
A Bistable Switch in Dynamic Thiodepsipeptide Folding and Template‐Directed Ligation
Authors: Mukherjee Rakesh , Cohen‐Luria Rivka , Wagner Nathaniel , Ashkenasy Gonen
Published: September 2015

Bistable reaction networks provide living cells with chemically controlled mechanisms for long‐term memory storage. Such networks are also often switchable and can be flipped from one state to the other. We target here a major challenge in systems chemistry research, namely developing synthetic, non‐enzymatic, networks that mimic such a complex function. Therefore, we describe a dynamic network that depending on initial thiodepsipeptide concentrations leads to one of two distinct steady states. This bistable system is readily switched by applying the appropriate stimuli. The relationship between the reaction network topology and its capacity to invoke bistability is then analyzed by control experiments and theory. We suggest that demonstrating bistable behavior using synthetic networks further highlights their possible role in early evolution, and may shine light on potential utility for novel applications, such as chemical memories.
The effects of on‐street parking on the service rate of nearby intersections
Authors: Cao Jin , Menendez Monica , Nikias Vasileios
Published: September 2015

An on‐street parking maneuver can often start a temporary bottleneck, leading to additional delay endured by the following vehicles. If the maneuver occurs near a signalized intersection, the service rate of the intersection might be reduced. In this paper, a model is built to analyze the effects of parking maneuvers on the intersection service rate. Based on the hydrodynamic theory of traffic flow, the perturbation caused by the parking maneuver is analyzed. Using dimensional analysis, we illustrate the relation between the background conditions, the distance from the parking area to the intersection, and the intersection service rate. Based on this relation, one can compute the service rate reduction caused by existing on‐street parking areas. A minimum distance between the parking area and the intersection to avoid such reduction can be accordingly found. Numerical examples based on empirical data from the city of Zurich, Switzerland, are provided to illustrate the practical applications. Although the analysis is based on streets with a single lane per direction, the findings can provide some insights regarding different situations. We hope such findings can be used as a basis for developing on‐street parking design guidelines. Copyright © 2015 John Wiley & Sons, Ltd.
Diversity in Reduction with Short‐Chain Dehydrogenases: Tetrahydroxynaphthalene Reductase, Trihydroxynaphthalene Reductase, and Glucose Dehydrogenase
Authors: Conradt David , Schätzle Michael A. , Husain Syed Masood , Müller Michael
Published: September 2015

NAD(P)H‐dependent oxidoreductases from the short‐chain dehydrogenases/reductases (SDRs) family possess high functional diversity. Three SDRs, namely, tetrahydroxy‐ and trihydroxynaphthalene reductases (T4HNR, T3HNR) involved in the dihydroxynaphthalene‐melanin biosynthesis of the phytopathogenic fungus Magnaporthe grisea, and glucose dehydrogenase (GDH) from Bacillus subtilis, were characterized regarding their substrate range and functional behavior. T4HNR and T3HNR share activities towards the stereoselective reduction of 2‐tetralone derivatives and 2,3‐dihydro‐1,4‐naphthoquinones and show distinct but different stereochemical outcome in the case of epoxy‐1,4‐napthoquinones as substrates. GDH shares the activity towards 2,3‐dihydro‐1,4‐naphthoquinones, however, with low stereocontrol. Moreover, GDH reduces 2‐hydroxy‐2,3‐dihydro‐1,4‐naphthoquinone into trans‐4‐hydroxyscytalone with a high diastereomeric excess (96 %), whereas T4HNR gave the cis diastereomer (diastereomeric excess>99 %). Thus, SDRs provide a much higher functional and stereochemical diversity than previously thought, already exemplified by many transformations of three members of this enzyme family.
Efficient Counter Electrode Manufactured from Ag2S Nanocrystal Ink for Dye‐Sensitized Solar Cells
Authors: He Qingquan , Huang Shoushuang , Zai Jiantao , Tang Nianqi , Li Bo , Qiao Qiquan , Qian Xuefeng
Published: September 2015

It is generally believed that silver or silver‐based compounds are not suitable counter electrode (CE) materials for dye‐sensitized solar cells (DSSCs) due to the corrosion of the I−/I3− redox couple in electrolytes. However, Ag2S has potential applications in DSSCs for catalyzing I3− reduction reactions because of its high carrier concentration and tiny solubility product constant. In the present work, CE manufactured from Ag2S nanocrystals ink exhibited efficient electrocatalytic activity in the reduction of I3− to I− in DSSCs. The DSSC consisting of Ag2S CE displayed a higher power conversion efficiency of 8.40 % than that of Pt CE (8.11 %). Moreover, the devices also showed the characteristics of fast activity onset, high multiple start/stop capability and good irradiated stability. The simple composition, easy preparation, stable chemical property, and good catalytic performance make the developed Ag2S CE as a promising alternative to Pt CE in DSSCs.
Innovative Disulfide Esters of Dithiocarbamic Acid as Women‐Controlled Contraceptive Microbicides: A Bioisosterism Approach
Authors: Mandalapu Dhanaraju , Lal Nand , Kumar Lokesh , Kushwaha Bhavana , Gupta Sonal , Kumar Lalit , Bala Veenu , Yadav Santosh K. , Singh Pratiksha , Singh Nidhi , Maikhuri Jagdamba P. , Sankhwar Satya N. , Shukla Praveen K. , Siddiqi Imran , Gupta Gopal , Sharma Vishnu L.
Published: September 2015

In an ongoing effort to discover an effective, topical, dual‐function, non‐surfactant contraceptive vaginal microbicide, a novel series of 2,2′‐disulfanediylbis(3‐(substituted‐1‐yl)propane‐2,1‐diyl) disubstituted‐1‐carbodithioates were designed by using a bioisosterism approach. Thirty‐three compounds were synthesized, and interestingly, most demonstrated multiple activities: they were found to be spermicidal at a minimal effective concentration of 1–0.001 %, trichomonacidal against drug‐susceptible and resistant Trichomonas strains at minimal inhibitory concentration (MIC) ranges of 10.81–377.64 and 10.81–754.14 μM, respectively, and fungicidal at MIC 7.93–86.50 μM. These compounds were also found to be non‐cytotoxic to human cervical (HeLa) epithelial cells and vaginal microflora (Lactobacilli) in vitro. The most promising compound, 2,2′‐disulfanediylbis(3‐(pyrrolidin‐1‐yl)propane‐2,1‐diyl)dipyrrolidine‐1‐carbodithioate (5), exhibited spermicidal activity 15‐fold higher than that of the marketed spermicide Nonoxynol‐9 (N‐9) and also demonstrated microbicidal potency. To identify common structural features required for spermicidal activity, a 3D‐QSAR analysis was carried out, as well as in vivo efficacy studies and fluorescent labeling studies to determine the biological targets of compound 5.
Phase Transformations of Copper Sulfide Nanocrystals: Towards Highly Efficient Quantum‐Dot‐Sensitized Solar Cells
Authors: Liu Lige , Liu Chang , Fu Wenping , Deng Luogen , Zhong Haizheng
Published: September 2015

Owing to their high electrical conductivity, tunable plasmonic absorption spectra, low cost, and abundance in nature, Cu2−xS nanocrystals are of great interest as functional materials for photovoltaic and photothermal applications. With the aim of developing low‐cost high‐efficiency quantum‐dot‐sensitized solar cells, solution‐processed Cu2−xS nanocrystal films are synthesized and their phase transformations upon thermal treatment are investigated. A combination of experimental results and theoretical analysis illustrates the thermodynamic evolution of the crystal structures and the composition caused by the thermal‐annealing process. The use of Cu2−xS nanocrystal films as counter electrodes in quantum‐dot‐sensitized solar cells is also explored. The devices have an optimized power‐conversion efficiency of 5.81 % for tetragonal Cu2S nanocrystal films that are derived from annealed Cu1.8S nanocrystal films.
Evaluation of longitudinal steroid profiles from male football players in UEFA competitions between 2008 and 2013
Authors: Baume Norbert , Geyer Hans , Vouillamoz Marc , Grisdale Richard , Earl Mike , Aguilera Rodrigo , Cowan David A. , Ericsson Magnus , Gmeiner Günter , Kwiatkowska Dorota , Kioukia‐Fougia Nassia , Molina Adeline , Ruivo João , Segura Jordi , Van Eenoo Peter , Jan Nicolas , Robinson Neil , Saugy Martial
Published: September 2015

Testosterone and related compounds are the most recurrent doping substances. The steroid profile, consisting of the quantification of testosterone and its metabolites, has been described as the most significant biomarker to detect doping with pseudo‐endogenous anabolic steroids. The steroidal module of the Athlete Biological Passport (ABP) was launched by the World Anti‐Doping Agency (WADA) in 2014. To assess the value of introducing the module to its anti‐doping programme, the Union of European Football Associations (UEFA) decided to analyze retrospectively the steroid profile data of 4195 urine samples, collected from 879 male football players and analyzed in 12 WADA‐accredited laboratories between 2008 and mid‐2013. This study focused on the evaluation of T/E ratios. The coefficient of variation (CV) and the adaptive model were the two statistical models used to study the longitudinal follow‐up. A CV of 46% was determined to be the maximal natural intra‐individual variation of the T/E when the sequence consisted of single data points analyzed in different laboratories. The adaptive model showed some profiles with an atypical T/E sequence and also enabled an estimate of the prevalence of external factors impacting the T/E sequences. Despite the limitations of this retrospective study, it clearly showed that the longitudinal and individual follow‐up of the T/E biomarker of the players is a good tool for target testing in football. UEFA has therefore decided to implement the steroidal module of the ABP from the start of the next European football season in September 2015. Copyright © 2015 John Wiley & Sons, Ltd.
Conspicuous male coloration impairs survival against avian predators in Aegean wall lizards, Podarcis erhardii
Authors: Marshall Kate L.A. , Philpot Kate E. , Stevens Martin
Published: September 2015

Animal coloration is strikingly diverse in nature. Within‐species color variation can arise through local adaptation for camouflage, sexual dimorphism and conspicuous sexual signals, which often have conflicting effects on survival. Here, we tested whether color variation between two island populations of Aegean wall lizards (Podarcis erhardii) is due to sexual dimorphism and differential survival of individuals varying in appearance. On both islands, we measured attack rates by wild avian predators on clay models matching the coloration of real male and female P. erhardii from each island population, modeled to avian predator vision. Avian predator attack rates differed among model treatments, although only on one island. Male‐colored models, which were more conspicuous against their experimental backgrounds to avian predators, were accordingly detected and attacked more frequently by birds than less conspicuous female‐colored models. This suggests that female coloration has evolved primarily under selection for camouflage, whereas sexually competing males exhibit costly conspicuous coloration. Unexpectedly, there was no difference in avian attack frequency between local and non‐local model types. This may have arisen if the models did not resemble lizard coloration with sufficient precision, or if real lizards behaviorally choose backgrounds that improve camouflage. Overall, these results show that sexually dimorphic coloration can affect the risk of predator attacks, indicating that color variation within a species can be caused by interactions between natural and sexual selection. However, more work is needed to determine how these findings depend on the island environment that each population inhabits.
Signatures of selection in the three‐spined stickleback along a small‐scale brackish water – freshwater transition zone
Authors: Konijnendijk Nellie , Shikano Takahito , Daneels Dorien , Volckaert Filip A.M. , Raeymaekers Joost A. M.
Published: September 2015

Local adaptation is often obvious when gene flow is impeded, such as observed at large spatial scales and across strong ecological contrasts. However, it becomes less certain at small scales such as between adjacent populations or across weak ecological contrasts, when gene flow is strong. While studies on genomic adaptation tend to focus on the former, less is known about the genomic targets of natural selection in the latter situation. In this study, we investigate genomic adaptation in populations of the three‐spined sticklebackGasterosteus aculeatusL. across a small‐scale ecological transition with salinities ranging from brackish to fresh. Adaptation to salinity has been repeatedly demonstrated in this species. A genome scan based on 87 microsatellite markers revealed only few signatures of selection, likely owing to the constraints that homogenizing gene flow puts on adaptive divergence. However, the detected loci appear repeatedly as targets of selection in similar studies of genomic adaptation in the three‐spined stickleback. We conclude that the signature of genomic selection in the face of strong gene flow is weak, yet detectable. We argue that the range of studies of genomic divergence should be extended to include more systems characterized by limited geographical and ecological isolation, which is often a realistic setting in nature.
PEGylated DOTA‐AHA‐Based GdIII Chelates: A Relaxometric Study
Authors: Fontes André , Karimi Shima , Helm Lothar , Ferreira Paula M. , André João P.
Published: September 2015

Three PEGylated derivatives of 6‐amino‐2‐[4,7,10‐tris(carboxymethyl)‐1,4,7,10‐tetrazacyclododec‐1‐yl]hexanoic acid (DOTA‐AHA) with different molecular weights were prepared and characterized. Their GdIII chelates were studied in aqueous solution through variable‐temperature 1H nuclear magnetic relaxation dispersion (NMRD) and 17O NMR spectroscopy to determine their relaxivities and the parameters that govern them. The relaxivity varied from 5.1 to 6.5 mM–1 s–1 (37 °C and 60 MHz) as the molecular weight of the polyethylene glycol (PEG) chain increased and was slightly higher than that of the parent chelate Gd(DOTA‐AHA), owing to a small contribution of a slow global rotation of the complexes. A variable‐temperature 1H NMR spectroscopy study of several LnIII chelates of DOTA‐A(PEG750)HA allowed the determination of the isomeric M/m ratio (M = square‐antiprismatic isomer and m = twisted square‐antiprismatic isomer; the latter presents a much faster water exchange), which was estimated to be ca. 1:0.2 for the GdIII chelate, very close to that of [Gd(DOTA)]–. This explains why the PEGylated GdIII chelate has a water rate exchange similar to that of [Gd(DOTA)]–. The predominance of the M isomer is a consequence of the bulky PEG moiety, which does not favor the stabilization of the m isomer in sterically crowded systems at the substituent site, in contrast to what happens with less packed asymmetrical DOTA‐type chelates with substitution at one of the four acetate C(α) atoms.
Simplified cryopreservation of the microalga Chlorella vulgaris integrating a novel concept for cell viability estimation
Authors: Morschett Holger , Reich Sebastian , Wiechert Wolfgang , Oldiges Marco
Published: September 2015

Microalgae currently receive growing attention as promising candidates for future bio‐economy concepts. However, the reliable maintenance of production strains remains challenging. The well‐established serial subculturing techniques suffer from low long‐time stability and high effort and are therefore stepwise being replaced by cryopreservation. Currently, available protocols are often deduced from cell culture technology and are rather complex. This study aimed to investigate if less complex approaches can be applied. We introduce an easy‐to‐use cryopreservation protocol based on the model organism Chlorella vulgaris. To overcome error‐prone viability estimation by plating techniques, an alternative method using growth pattern analysis was developed. As revealed by growth pattern analysis, the preservation of stationary phase cells proved superior to the commonly applied concept of freezing cells from the growing phase. Controlled‐rate cooling using simple devices resulted in reproducibly high post‐thawing viabilities in the range of 63 ± 2%. Moreover, the presented protocol highlights the potential of simplifying microalgal cryo‐preservation procedures, thereby reducing the required labor and material need to a minimum. Apart from the viability analysis of the cryopreserved microalga C. vulgaris, this approach seems to have the potential to be applied for other algae species and microorganisms, as well.