bluuebunny/crossref_metadata_2025 huggingface dataset:
GGGGCC microsatellite RNA is neuritically localized, induces branching defects, and perturbs transport granule function
Authors: Burguete Alondra Schweizer , Almeida Sandra , Gao Fen-Biao , Kalb Robert , Akins Michael R , Bonini Nancy M
Published: December 2015

Microsatellite expansions are the leading cause of numerous neurodegenerative disorders. Here we demonstrate that GGGGCC and CAG microsatellite repeat RNAs associated with C9orf72 in amyotrophic lateral sclerosis/frontotemporal dementia and with polyglutamine diseases, respectively, localize to neuritic granules that undergo active transport into distal neuritic segments. In cultured mammalian spinal cord neurons, the presence of neuritic GGGGCC repeat RNA correlates with neuronal branching defects, and the repeat RNA localizes to granules that label with fragile X mental retardation protein (FMRP), a transport granule component. Using a Drosophila GGGGCC expansion disease model, we characterize dendritic branching defects that are modulated by FMRP and Orb2. The human orthologs of these modifiers are misregulated in induced pluripotent stem cell-differentiated neurons (iPSNs) from GGGGCC expansion carriers. These data suggest that expanded repeat RNAs interact with the messenger RNA transport and translation machinery, causing transport granule dysfunction. This could be a novel mechanism contributing to the neuronal defects associated with C9orf72 and other microsatellite expansion diseases.
Internal models for interpreting neural population activity during sensorimotor control
Authors: Golub Matthew D , Yu Byron M , Chase Steven M
Published: December 2015

To successfully guide limb movements, the brain takes in sensory information about the limb, internally tracks the state of the limb, and produces appropriate motor commands. It is widely believed that this process uses an internal model, which describes our prior beliefs about how the limb responds to motor commands. Here, we leveraged a brain-machine interface (BMI) paradigm in rhesus monkeys and novel statistical analyses of neural population activity to gain insight into moment-by-moment internal model computations. We discovered that a mismatch between subjects’ internal models and the actual BMI explains roughly 65% of movement errors, as well as long-standing deficiencies in BMI speed control. We then used the internal models to characterize how the neural population activity changes during BMI learning. More broadly, this work provides an approach for interpreting neural population activity in the context of how prior beliefs guide the transformation of sensory input to motor output.
Precise assembly of complex beta sheet topologies from de novo designed building blocks
Authors: King Indigo Chris , Gleixner James , Doyle Lindsey , Kuzin Alexandre , Hunt John F , Xiao Rong , Montelione Gaetano T , Stoddard Barry L , DiMaio Frank , Baker David
Published: December 2015

Design of complex alpha-beta protein topologies poses a challenge because of the large number of alternative packing arrangements. A similar challenge presumably limited the emergence of large and complex protein topologies in evolution. Here, we demonstrate that protein topologies with six and seven-stranded beta sheets can be designed by insertion of one de novo designed beta sheet containing protein into another such that the two beta sheets are merged to form a single extended sheet, followed by amino acid sequence optimization at the newly formed strand-strand, strand-helix, and helix-helix interfaces. Crystal structures of two such designs closely match the computational design models. Searches for similar structures in the SCOP protein domain database yield only weak matches with different beta sheet connectivities. A similar beta sheet fusion mechanism may have contributed to the emergence of complex beta sheets during natural protein evolution.
Ion channels and calcium signaling in motile cilia
Authors: Doerner Julia F , Delling Markus , Clapham David E
Published: December 2015

The beating of motile cilia generates fluid flow over epithelia in brain ventricles, airways, and Fallopian tubes. Here, we patch clamp single motile cilia of mammalian ependymal cells and examine their potential function as a calcium signaling compartment. Resting motile cilia calcium concentration ([Ca2+] ~170 nM) is only slightly elevated over cytoplasmic [Ca2+] (~100 nM) at steady state. Ca2+ changes that arise in the cytoplasm rapidly equilibrate in motile cilia. We measured CaV1 voltage-gated calcium channels in ependymal cells, but these channels are not specifically enriched in motile cilia. Membrane depolarization increases ciliary [Ca2+], but only marginally alters cilia beating and cilia-driven fluid velocity within short (~1 min) time frames. We conclude that beating of ependymal motile cilia is not tightly regulated by voltage-gated calcium channels, unlike that of well-studied motile cilia and flagella in protists, such as Paramecia and Chlamydomonas.
A versatile pipeline for the multi-scale digital reconstruction and quantitative analysis of 3D tissue architecture
Authors: Morales-Navarrete Hernán , Segovia-Miranda Fabián , Klukowski Piotr , Meyer Kirstin , Nonaka Hidenori , Marsico Giovanni , Chernykh Mikhail , Kalaidzidis Alexander , Zerial Marino , Kalaidzidis Yannis
Published: December 2015

A prerequisite for the systems biology analysis of tissues is an accurate digital three-dimensional reconstruction of tissue structure based on images of markers covering multiple scales. Here, we designed a flexible pipeline for the multi-scale reconstruction and quantitative morphological analysis of tissue architecture from microscopy images. Our pipeline includes newly developed algorithms that address specific challenges of thick dense tissue reconstruction. Our implementation allows for a flexible workflow, scalable to high-throughput analysis and applicable to various mammalian tissues. We applied it to the analysis of liver tissue and extracted quantitative parameters of sinusoids, bile canaliculi and cell shapes, recognizing different liver cell types with high accuracy. Using our platform, we uncovered an unexpected zonation pattern of hepatocytes with different size, nuclei and DNA content, thus revealing new features of liver tissue organization. The pipeline also proved effective to analyse lung and kidney tissue, demonstrating its generality and robustness.
Striatal dynamics explain duration judgments
Authors: Gouvêa Thiago S , Monteiro Tiago , Motiwala Asma , Soares Sofia , Machens Christian , Paton Joseph J
Published: December 2015

The striatum is an input structure of the basal ganglia implicated in several time-dependent functions including reinforcement learning, decision making, and interval timing. To determine whether striatal ensembles drive subjects' judgments of duration, we manipulated and recorded from striatal neurons in rats performing a duration categorization psychophysical task. We found that the dynamics of striatal neurons predicted duration judgments, and that simultaneously recorded ensembles could judge duration as well as the animal. Furthermore, striatal neurons were necessary for duration judgments, as muscimol infusions produced a specific impairment in animals' duration sensitivity. Lastly, we show that time as encoded by striatal populations ran faster or slower when rats judged a duration as longer or shorter, respectively. These results demonstrate that the speed with which striatal population state changes supports the fundamental ability of animals to judge the passage of time.
Investigation of the biaxial stress of Al-doped ZnO thin films on a flexible substrate with RF magnetron sputtering
Authors: Huang Kuo-Ting , Chen Hsi-Chao , Cheng Po-Wei , Chang Jhe-Ming
Published: December 2015

Transparent conductive Al-doped ZnO (AZO) thin films were deposited onto poly(ethylene terephthalate) (PET) substrate, using the radio frequency (RF) magnetron sputtering method. The residual stress of flexible electronics was investigated by a double beam shadow moiré interferometer with phase shifting interferometry (PSI). Moreover, the biaxial stress of AZO thin films can be graphically represented by using Mohr’s circle of stress. The residual stress of AZO thin films becomes more compressive with the increase in sputtering power. The maximum residual stress is −1115.74 MPa, and the shearing stress is 490.57 MPa at a sputtering power of 200 W. The trends of residual stress were evidenced by the X-ray diffraction (XRD) patterns and optical properties of AZO thin films. According to the evaluation results of the refractive index and the extinction coefficient, the AZO thin films have better quality when the sputtering power less than 100 W.
Intramale variation in sperm size: functional significance in a polygynous mammal
Authors: Ros-Santaella José Luis , Pintus Eliana , Garde José Julián
Published: December 2015

Studies concerning the relationships between sperm size and velocity at the intraspecific level are quite limited and often yielded contradictory results across the animal kingdom. Intramale variation in sperm size may represent a meaningful factor to predict sperm velocity, due to its relationship with the level of sperm competition among related taxa. Because sperm phenotype is under post-copulatory sexual selection, we hypothesized that a reduced intramale variation in sperm size is associated with sperm competitiveness in red deer. Our results show that low variation in sperm size is strongly related to high sperm velocity and normal sperm morphology, which in turn are good predictors of male fertility in this species. Furthermore, it is well known that the red deer show high variability in testicular mass but there is limited knowledge concerning the significance of this phenomenon at intraspecific level, even though it may reveal interesting processes of sexual selection. Thereby, as a preliminary result, we found that absolute testes mass is negatively associated with intramale variation in sperm size. Our findings suggest that sperm size variation in red deer is under a strong selective force leading to increase sperm function efficiency, and reveal new insights into sexual selection mechanisms.
O processo decisório e o uso das lógicas effectuation e causation, frente à transição da pequena para a média empresa: casos do setor hoteleiro na cidade de Curitiba-PR
Authors: Leucz Talita , Andreassi Tales
Published: December 2015

O presente estudo busca analisar como as mudanças ocasionadas pelo crescimento da empresa afetam o processo decisório, com foco na transição de pequena para média empresa. Tal tema é muito pouco explorado na literatura, principalmente sob os aspectos abordados pelas lógicas Effectuation e Causation, descritas por Sarasvathy (2001).  A pesquisa teve caráter qualitativo e exploratório e fez uso do método de estudos de casos, por meio de entrevistas em profundidade com empreendedores, sucessores e gerentes de dois hotéis na cidade de Curitiba, setor este que apresenta grande visibilidade e crescimento nos últimos anos. Ao finalizar a pesquisa, concluiu-se que a transição de pequena para média empresa afeta as decisões no sentido de i) aumentar a formalização de processos, ii) ocorrer uma maior delegação de pequenos poderes, iii) haver um maior distanciamento entre funcionários e a cúpula administrativa, iv) ter uma preocupação maior com a capacitação dos funcionários, v) levar em consideração aspectos racionais na decisão, vi) haver uma equipe de suporte para tomada de decisões, vii) haver uma preocupação com o longo prazo, viii) as responsabilidades tornam-se mais claras e ix) mais autonomia é delegada aos funcionários.
Turismo e sustentabilidade ambiental na comunidade de Barra Grande, Cajueiro da Praia, Piauí (PI)
Authors: Vieira Anderson Fontenele , Araújo José Luís Lopes
Published: December 2015

A comunidade de Barra Grande, destino turístico localizado no município de Cajueiro da Praia, Piauí (PI), foi objeto de investigação deste estudo. O turismo nesta região cresceu gerando mudanças estruturais, sociais e ambientais. O objetivo da pesquisa foi analisar os impactos ambientais do turismo em Barra Grande considerando os Indicadores de Sustentabilidade Ambiental (ISA) do IBGE (Instituto Brasileiro de Geografia e Estatística). Foi realizado levantamento bibliográfico e documental sobre as políticas públicas de turismo e meio ambiente, além da aplicação de entrevistas semiestruturadas com dezoito meios de hospedagem diagnosticando três indicadores: abastecimento de água, esgotamento sanitário, e coleta e destinação de resíduos sólidos, que mensuraram parâmetros de pressão (impactos) ao meio natural, qualificaram o estado desse meio e a existência de mecanismos de reposta na minimização dos impactos. A relevância científica consiste na análise da sustentabilidade, por meio de indicadores embasados no Modelo PER (Pressão-Estado-Resposta), adotado pela OECD (Organização para a Cooperação e Desenvolvimento Econômico), de modo a conduzir ações estratégicas para solucionar os problemas ambientais. Quanto aos resultados preliminares, percebeu-se, que as políticas apresentam parte das suas normatizações não empreendidas na prática. No tocante a coleta de campo nos meios de hospedagem, identificou-se que estes estão de acordo com dois dos parâmetros qualitativos avaliados, comprovando que o destino precisa melhorar quanto a sustentabilidade. Por fim, espera-se que os dados possam contribuir no planejamento turístico, além de construir elementos para subsidiar discussões, novas abordagens de pesquisa sobre a viabilidade e adesão de segmentos turísticos sustentáveis no contexto do estado do Piauí ou de outras regiões do Brasil.
Sigma Receptor Binding Assays
Authors: Chu Uyen B. , Ruoho Arnold E.
Published: December 2015

Sigma receptors, both Sigma‐1(S1R) and Sigma‐2 (S2R), are small molecule‐regulated, primarily endoplasmic reticulum (ER) membrane‐associated sites. A number of drugs bind to sigma receptors, including the antipsychotic haloperidol and (+)‐pentazocine, an opioid analgesic. Sigma receptors are implicated in many central nervous system disorders, in particular Alzheimer's disease and conditions associated with motor control, such as Amyotrophic Lateral Sclerosis (ALS). Described in this unit are radioligand binding assays used for the pharmacological characterization of S1R and S2R. Methods detailed include a radioligand saturation binding assay for defining receptor densities and a competitive inhibition binding assay employing [3H]‐(+)‐pentazocine for identifying and characterizing novel ligands that interact with S1R. Procedures using [3H]‐1,3‐di(2‐tolyl)guanidine ([3H]‐DTG), a nonselective sigma receptor ligand, are described for conducting a saturation binding and competitive inhibition assays for the S2R site. These protocols are of value in drug discovery in identifying new sigma ligands and in the characterization of these receptors. © 2015 by John Wiley & Sons, Inc.
In Vitro Binding of [3H]PSB‐0413 to P2Y12 Receptors
Authors: Dupuis Arnaud , Heim Véronique , Ohlmann Philippe , Gachet Christian
Published: December 2015

The P2Y12 /ADP receptor plays a central role in platelet activation. Characterization of this receptor is mandatory for studying disorders associated with a P2Y12 receptor defect and for evaluating P2Y12 receptor agonists and antagonists. In the absence of suitable anti‐P2Y12 antibodies, radioligand binding assays are the only way to conduct such studies. While various radioligands were employed in the past for this purpose, none were found to be suitable for routine use. Described in this unit are protocols for quantitatively and qualitatively assessing P2Y12 receptors with [3H]PSB‐0413, a selective antagonist for this site. The saturation and competition assays described herein make possible the determination of P2Y12 receptor density on cells, as well as the potencies and affinities of test agents at this site. © 2015 by John Wiley & Sons, Inc.
The impact of climatic and atmospheric teleconnections on the brine inventory over the Laptev Sea shelf between 2007 and 2011
Authors: Thibodeau Benoit , Bauch Dorothea
Published: December 2015

Export of brine‐enriched water from Siberian shelves is thought to be a key parameter in maintaining the Arctic Halocline, which isolates the fresh and cold surface water from the warm Atlantic water and thus prevent dramatic change in the Arctic sea‐ice thermodynamic. In this study, we used 5 years of oxygen isotope and hydrological summer surveys to better understand the factors controlling the brine inventory and distribution over the Laptev Sea shelf. The inventory was maximal in 2011 and 2007 and minimal in 2010. The brine inventory interannual variations are coherent with the winter Arctic Oscillation index that was maximal in 2011 and 2007 and minimal in 2010, which is known to modulate Arctic winds and sea‐ice export pattern. While we should remain cautious since our record is limited to 5 years, our results suggest that the combined effect of the Arctic Oscillation and of the Arctic Dipole is the main factor controlling the annual variations in the inventory of brine‐enriched waters from the Laptev Sea shelf between 2007 and 2011, especially during extreme negative Arctic Oscillation and Arctic Dipole conditions as in 2010.
Stress state and its anomaly observations in the vicinity of a fault in NanTroSEIZEExpedition 322
Authors: Wu Hung‐Yu , Saito Saneatsu , Kinoshita Masataka
Published: December 2015

To better understand the stress state and geological properties within the shallow Shikoku Basin, southwest of Japan, two sites, C0011A and C0011B, were drilled in open‐ocean sediments using Logging While Drilling (LWD) and coring, respectively. Resistivity image logging was performed at C0011A from sea floor to 950 m below sea floor (mbsf). At C0011B, the serial coring was obtained in order to determine physical properties from 340 to 880 mbsf. For the LWD images, a notable breakout anomaly was observed at a depth of 615 m. Using resistivity images and a stress polygon, the potential horizontal principal stress azimuth and its magnitude within the 500–750 mbsf section of the C0011A borehole were constrained. Borehole breakout azimuths were observed for the variation by the existence of a fault zone at a depth of 615 mbsf. Out of this fracture zone, the breakout azimuth was located at approximately 109° ± 12°, subparallel to the Nankai Trough convergence vector (300–315°). Our calculations describe a stress drop was determined based on the fracture geometry. A close 90° (73° ± 12°) rotation implied a 100% stress drop, defined as a maximum shear stress drop equal to 1 MPa. The magnitude of the horizontal principal stresses near the fracture stress anomaly ranged between 49 and 52 MPa, and the bearing to the vertical stress (Sv = 52 MPa) was found to be within the normal‐faulting stress regime. Low rock strength and a low stress level are necessary to satisfy the observations.
Influence of anthropogenic groundwater unloading in Indo‐Gangetic plains on the 25 April 2015 Mw 7.8 Gorkha, Nepal earthquake
Authors: Kundu Bhaskar , Vissa Naresh Krishna , Gahalaut V. K.
Published: December 2015

Groundwater usage in the Indo‐Gangetic plains exceeds replenishment of aquifers, leading to substantial reduction in the mass. Such anthropogenic crustal unloading may promote long‐term fault slip or may modulate seismic activity in the adjoining Himalayan region. Our simulation using Gravity Recovery and Climate Experiment data and hydrological models of such a process indicates that the thrust earthquakes on the Main Himalayan Thrust (MHT), including the recent 25 April 2015 Mw 7.8 Gorkha, Nepal earthquake, are probably influenced by the anthropogenic groundwater unloading process in the Gangetic plains. The groundwater withdrawal leading to crustal unloading in the Gangetic plains causes a significant component of horizontal compression which adds to the secular interseimic compression at the seismogenic depth (5–20 km) on the MHT beneath the Himalayan arc and at hypocentral depth of the 2015 Gorkha, Nepal earthquake. This effect enhances the Coulomb stress on the locked zone of MHT.
Differential uplift and incision of the Yakima River terraces, central Washington State
Authors: Bender Adrian M. , Amos Colin B. , Bierman Paul , Rood Dylan H. , Staisch Lydia , Kelsey Harvey , Sherrod Brian
Published: December 2015

The fault‐related Yakima folds deform Miocene basalts and younger deposits of the Columbia Plateau in central Washington State. Geodesy implies ~2 mm/yr of NNE directed shortening across the folds, but until now the distribution and rates of Quaternary deformation among individual structures has been unclear. South of Ellensburg, Washington, the Yakima River cuts a ~600 m deep canyon across several Yakima folds, preserving gravel‐mantled strath terraces that record progressive bedrock incision and related rock uplift. Here we integrate cosmogenic isochron burial dating of the strath terrace gravels with lidar analysis and field mapping to quantify rates of Quaternary differential incision and rock uplift across two folds transected by the Yakima River: Manastash and Umtanum Ridge. Isochron burial ages from in situ produced26Al and10Be at seven sites across the folds date episodes of strath terrace formation over the past ~2.9 Ma. Average bedrock incision rates across the Manastash (~88 m/Myr) and Umtanum Ridge (~46 m/Myr) anticlines are roughly 4 to 8 times higher than rates in the intervening syncline (~14 m/Myr) and outside the canyon (~10 m/Myr). These contrasting rates demonstrate differential bedrock incision driven by ongoing Quaternary rock uplift across the folds at rates corresponding to ~0.13 and ~0.06 mm/yr shortening across postulated master faults dipping 30 ± 10°S beneath the Manastash and Umtanum Ridge anticlines, respectively. The reported Quaternary shortening across the anticlines accounts for ~10% of the ~2 mm/yr geodetic budget, suggesting that other Yakima structures actively accommodate the remaining contemporary deformation.
Refinement of the critical angle calculation for the contrast reversal of oil slicks under sunglint
Authors: Lu Yingcheng , Sun Shaojie , Zhang Minwei , Murch Brock , Hu Chuanmin
Published: December 2015

It has long been observed that oil slicks under sunglint can reverse their optical contrast against nearby oil‐free seawater. Such a phenomenon has been described through both empirical statistical analysis of the sunglint strength and modeled theoretically using a critical angle concept. The critical angle, in this model, is the angle at which the image pixels show no or negligible contrast between oiled and nonoiled seawater. Pixels away from this critical angle show either positive or negative contrast from the oil‐free pixels. Although this concept has been fully demonstrated in the published literature, its calculation needs to be further refined to take into account: (1) the different refractive indices of oil slicks (from natural seeps) and seawater and (2) atmospheric effects in the sensor‐measured radiance. Using measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) over oil films in the Gulf of Mexico, we show improvement in the modeled and MODIS‐derived reflectance over oil slicks originated from natural seeps after incorporating these two factors in the model. Specifically, agreement between modeled and measured sunglint reflectance is found for both negative and positive‐contrasting oil slicks. These results indicate that surface roughness and reflectance from oil films can be estimated given any solar/viewing geometry and surface wind. Further, this model might be used to correct the sunglint effect on thick oil under similar illumination conditions. Once proven possible, it may allow existing laboratory‐based models, which estimate oil thickness after such corrections, to be applied to remote sensing imagery.
PDO and ENSO modulations intensified decadal sea level variability in the tropical Pacific
Authors: Moon Jae‐Hong , Song Y. Tony , Lee HuiKyo
Published: December 2015

According to long‐term sea level reconstruction and steric sea level data, regional sea levels in the tropical Pacific have oscillated between east and west on a decadal time scale over the past 60 years, but the oscillation has been intensified significantly in the last three decades. Using conditional composite analysis, we show that the recent intensification in sea level variability is caused by modulation between the Pacific Decadal Oscillation (PDO) and El Niño‐Southern Oscillation (ENSO), i.e., an El Niño in a positive PDO or a La Niña in a negative PDO phase. Our analysis of meteorological fields indicates that atmospheric circulation associated with the changes in ENSO‐PDO phase relationship plays a positive role in enhancing the decadal sea level oscillation. The intensified sea level oscillation, when superimposed on the global trend of sea level rise, will have profound implications for coastal communities, therefore, the combined effect of PDO and ENSO should be taken into account in the decadal sea level prediction in the tropical Pacific.
On the vertical phytoplankton response to an ice‐free Arctic Ocean
Authors: Lawrence J. , Popova E. , Yool A. , Srokosz M.
Published: December 2015

Rapidly retreating sea ice is expected to influence future phytoplankton production in the Arctic Ocean by perturbing nutrient and light fields, but poor understanding of present phytoplankton distributions and governing mechanisms make projected changes highly uncertain. Here we use a simulation that reproduces observed seasonal phytoplankton chlorophyll distributions and annual nitrate to hypothesize that surface nitrate limitation in the Arctic Ocean deepens vertical production distributions where light‐dependent growth rates are lower. We extend this to interpret depth‐integrated production changes projected by the simulation for an ice‐free Arctic Ocean. Future spatial changes correspond to patterns of reduced surface nitrate and increased light. Surface nitrate inventory reductions in the Beaufort Gyre and Atlantic inflow waters drive colocated production distributions deeper to where light is lower, offsetting increases in light over the water column due to reduced ice cover and thickness. Modest production increases arise, 10% in a seasonally ice‐free Arctic Ocean and increasing to 30% by the end of the century, occurring at depth.
Resolving the impact of stratosphere‐to‐troposphere transport on the sulfur cycle and surface ozone over the Tibetan Plateau using a cosmogenic 35S tracer
Authors: Lin Mang , Zhang Zhisheng , Su Lin , Hill‐Falkenthal Jason , Priyadarshi Antra , Zhang Qianggong , Zhang Guoshuai , Kang Shichang , Chan Chuen‐Yu , Thiemens Mark H.
Published: December 2015

The Himalayas were recently identified as a global hot spot for deep stratosphere‐to‐troposphere transport (STT) in spring. Although the STT in this region may play a vital role in tropospheric chemistry, the hydrological cycle and aquatic ecosystems in Asia, there is no direct measurement of a chemical stratospheric tracer to verify and evaluate its possible impacts. Here we use cosmogenic 35S as a tracer for air masses originating in the stratosphere and transported downward. We measure concentrations of 35S in fresh surface snow and river runoff samples collected from Mount Everest in April 2013 to be more than 10 times higher than previously reported by any surface measurement, in support of the Himalayas as a gateway of springtime STT. In light of this result, measurements of 35SO2 and 35SO42− at Nam Co in spring 2011 are reanalyzed to investigate the magnitudes of stratospheric air masses from the Himalayas to the tropospheric sulfur cycle and surface O3 level over the Tibetan Plateau. A simple one‐box model reveals that the oxidative lifetime of SO2 is reduced in aged STT plumes. Triple oxygen isotopic measurements of sulfate samples suggest that enhanced O3 levels may shift the oxidation pathway of SO2 in the troposphere, which may be constrained by further intensive sampling and measurements. Comparison with surface O3 measurements and traditional meteorological tracing methods shows that 35S is a potentially unique and sensitive tracer to quantify the contribution of stratospheric air to surface O3 levels in fresh or aged STT plumes.
Characterizing interannual variability of glacier dynamics and dynamic discharge (1999–2015) for the ice masses of Ellesmere and Axel Heiberg Islands, Nunavut, Canada
Authors: Van Wychen Wesley , Davis Jamie , Burgess David O. , Copland Luke , Gray Laurence , Sharp Martin , Mortimer Colleen
Published: December 2015

Landsat 7 and RADARSAT‐1/RADARSAT‐2 satellite images are used to produce the most comprehensive record of glacier motion in the Canadian High Arctic to date and to characterize spatial and temporal variability in ice flow over the past ~15 years. This allows us to assess whether dynamically driven glacier change can be attributed to “surging” or “pulsing,” or whether other mechanisms are involved. RADAR velocity mapping allows annual regional dynamic discharge (iceberg calving) to be calculated for 2000 and the period 2011–2015 (yielding a mean regional discharge of 2.21 ± 0.68 Gt a−1), and velocities derived from feature tracking of optical imagery allow for annual dynamic discharge to be calculated for select glaciers from 1999 to 2010. Since ~2011, several of the major tidewater‐terminating glaciers within the region have decelerated and their dynamic discharge has decreased. Trinity and Wykeham Glaciers (Prince of Wales Icefield) represent a notable departure from this pattern as they have generally accelerated over the study period. The resulting increase in dynamic discharge from these glaciers entirely compensates (within error limits) for the decrease in discharge from the other tidewater glaciers across the study region. These two glaciers accounted for ~62% of total regional dynamic discharge in winter 2015 (compared to ~22% in 2000), demonstrating that total ice discharge from the Canadian High Arctic can be sensitive to variations in flow of just a few tidewater glaciers.
Vertical land motion as a key to understanding sea level change and variability
Authors: Wöppelmann Guy , Marcos Marta
Published: December 2015

Vertical land motions are a key element in understanding how sea levels have changed over the past century and how future sea levels may impact coastal areas. Ideally, to be useful in long‐term sea level studies, vertical land motion should be determined with standard errors that are 1 order of magnitude lower than the contemporary climate signals of 1 to 3 mm/yr observed on average in sea level records, either using tide gauges or satellites. This metrological requirement constitutes a challenge in geodesy. Here we review the most successful instrumental methods that have been used to determine vertical displacements at the Earth's surface, so that the objectives of understanding and anticipating sea levels can be addressed adequately in terms of accuracy. In this respect, the required level of uncertainty is examined in two case studies (global and local). A special focus is given to the use of the Global Positioning System (GPS) and to the combination of satellite radar altimetry with tide gauge data. We update previous data analyses and assess the quality of global satellite altimetry products available to the users for coastal applications. Despite recent advances, a near‐plateau level of accuracy has been reached. The major limitation is the realization of the terrestrial reference frame, whose physical parameters, the origin and the scale factor, are beyond the scope of a unique technique such as the GPS. Additional practical but nonetheless important issues are associated with the installation of GPS antennas, such as ensuring that there is no unknown differential vertical motion with the tide gauge.
Representing low‐frequency variability in continuous rainfall simulations: A hierarchical random Bartlett Lewis continuous rainfall generation model
Authors: Wasko Conrad , Pui Alexander , Sharma Ashish , Mehrotra Rajeshwar , Jeremiah Erwin
Published: December 2015

Low‐frequency variability, in the form of the El Niño‐Southern Oscillation, plays a key role in shaping local weather systems. However, current continuous stochastic rainfall models do not account for this variability in their simulations. Here a modified Random Pulse Bartlett Lewis stochastic generation model is presented for continuous rainfall simulation exhibiting low‐frequency variability. Termed the Hierarchical Random Bartlett Lewis Model (HRBLM), the model features a hierarchical structure to represent a range of rainfall characteristics associated with the El Niño‐Southern Oscillation with parameters conditioned to vary as functions of relevant climatic states. Long observational records of near‐continuous rainfall at various locations in Australia are used to formulate and evaluate the model. The results indicate clear benefits of using the hierarchical climate‐dependent structure proposed. In addition to accurately representing the wet spells characteristics and observed low‐frequency variability, the model replicates the interannual variability of the antecedent rainfall preceding the extremes, which is known to be of considerable importance in design flood estimation applications.
Amino‐Functionalized Conjugated Polymer as an Efficient Electron Transport Layer for High‐Performance Planar‐Heterojunction Perovskite Solar Cells
Authors: Sun Chen , Wu Zhihong , Yip Hin‐Lap , Zhang Hua , Jiang Xiao‐Fang , Xue Qifan , Hu Zhicheng , Hu Zhanhao , Shen Yan , Wang Mingkui , Huang Fei , Cao Yong
Published: December 2015

An amino‐functionalized copolymer with a conjugated backbone composed of fluorene, naphthalene diimide, and thiophene spacers (PFN‐2TNDI) is introduced as an alternative electron transport layer (ETL) to replace the commonly used [6,6]‐Phenyl‐C61‐butyric acid methyl ester (PCBM) in the p–i–n planar‐heterojunction organometal trihalide perovskite solar cells. A combination of characterizations including photoluminescence (PL), time‐resolved PL decay, Kelvin probe measurement, and impedance spectroscopy is used to study the interfacial effects induced by the new ETL. It is found that the amines on the polymer side chains not only can passivate the surface traps of perovskite to improve the electron extraction properties, they also can reduce the work function of the metal cathode by forming desired interfacial dipoles. With these dual functionalities, the resulted solar cells outperform those based on PCBM with power conversion efficiency (PCE) increased from 12.9% to 16.7% based on PFN‐2TNDI. In addition to the performance enhancement, it is also found that a wide range of thicknesses of the new ETL can be applied to produce high PCE devices owing to the good electron transport property of the polymer, which offers a better processing window for potential fabrication of perovskite solar cells using large‐area coating method.
Engineering Cobalt Phosphide (CoP) Thin Film Catalysts for Enhanced Hydrogen Evolution Activity on Silicon Photocathodes
Authors: Hellstern Thomas R. , Benck Jesse D. , Kibsgaard Jakob , Hahn Christopher , Jaramillo Thomas F.
Published: December 2015

Transition metal phosphide catalysts have recently emerged as active, earth abundant alternatives to precious metals for the hydrogen evolution reaction in acid. High performance, scalable catalysts are necessary for the successful implementation of photoelectrochemical water splitting devices, which have the potential to generate hydrogen in a sustainable manner. Herein, a general synthetic route is reported to produce transition metal phosphide thin films, which is used to fabricate cobalt phosphide (CoP) catalysts with high average turnover frequency (TOFavg), 0.48 H2 s−1 and 1.0 H2 s−1 at 100 and 120 mV overpotential, respectively. Furthermore, it is shown that CoP thin films can be applied to silicon photoabsorbers to generate one of the most active precious metal‐free crystalline silicon photocathodes to date, achieving −10 mA cm−2 at +0.345 V vs. reversible hydrogen electrode. The synthesis route presented here provides a platform for both fundamental studies of well‐defined electrocatalysts and the fabrication of high‐performance photoelectrodes.
The importance of gravity in droplet evaporation: A comparison of pendant and sessile drop evaporation with particles
Authors: Devlin Nicole Raley , Loehr Katherine , Harris Michael T.
Published: December 2015

As a droplet with particles evaporates, the particles deposit on the substrate surface. In this work, we show the extent of gravitational effects on the particle deposition profile and propose a new model for particle tracing in an evaporating droplet which accounts for gravitational effects. Experimentally, we compare pendant and sessile water droplets with 1 and 3 μm polystyrene particles. Numerically, the finite element method was used to create a transport model of the evaporating droplet system and particle deposition. The numerical and experimental results have excellent agreement and show that a pendant water droplet with 1 and 3 μm polystyrene spheres has significant separation of the two particle sizes. Finally, a phase diagaram was created to map different deposition profiles for various gravitational Péclet numbers (PeG) and ratios of Péclet number to Damköhler number (Pe/Da). © 2015 American Institute of Chemical Engineers AIChE J, 62: 947–955, 2016
Low concentration sand transport in multiphase viscous horizontal pipes: An experimental study and modeling guideline
Authors: Najmi Kamyar , McLaury Brenton S. , Shirazi Siamack A. , Cremaschi Selen
Published: December 2015

Low concentration particle transport in multiphase horizontal pipes in the presence of a viscous liquid is experimentally investigated. The experiments were conducted for a wide range of liquid and gas flow rates in both intermittent and stratified flows. Critical flow rates (velocity) is defined as the minimum required liquid and gas flow rates (velocities) to keep particles constantly moving in the pipe. The effects of physical parameters such as sand concentration, sand size, pipe size, and liquid viscosity are also experimentally investigated. It is observed that that critical velocity is a function of sand concentration and sand size and increases by increasing either within the ranges of particle concentrations and sizes examined. Regarding the effect of carrier liquid viscosity, the experimental data reveal that by increasing viscosity the minimum required flow rates to constantly move sand along the pipe increases within the range examined. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1821–1833, 2016
Metal‐Free C(sp3)‐O Bond Formation through Radical Translocation: A Mild, Efficient, and Practical Approach to α‐Alkoxybenzamides
Authors: Huang Feng‐Qing , Zhou Guo‐Xiu , Dong Xin , Qi Lian‐Wen , Zhang Bo
Published: December 2015

A mild and metal‐free method to functionalize aliphatic C−H bonds adjacent to a nitrogen atom through radical translocation, oxidation to an iminium intermediate, and nucleophilic trapping with alcohols is described. The transformation proceeds efficiently with edible ascorbic acid (vitamin C) as the radical initiator and readily available tert‐butyl nitrite as the nitrosating reagent. Notably, any transition‐metal or additive is not required. The current method provides simple, efficient, and practical access to valuable α‐alkoxybenzamides in moderate to good yields.
Binuclear Aromatic C−H Bond Activation at a Dirhenium Site
Authors: Adams Richard D. , Rassolov Vitaly , Wong Yuen Onn
Published: December 2015

The electronically unsaturated dirhenium complex [Re2(CO)8(μ‐H)(μ‐Ph)] (1) has been found to exhibit aromatic C−H activation upon reaction with N,N‐diethylaniline, naphthalene, and even [D6]benzene to yield the compounds [Re2(CO)8(μ‐H)(μ‐η1‐NEt2C6H4)] (2), [Re2(CO)8(μ‐H)(μ‐η2‐1,2‐C10H7)] (3), and [D6]‐1, respectively, in good yields. The mechanism has been elucidated by using DFT computational analyses, and involves a binuclear C−H bond‐activation process.
Click Functionalization of a Dibenzocyclooctyne‐Containing Conjugated Polyimine
Authors: Kardelis Vladimir , Chadwick Ryan C. , Adronov Alex
Published: December 2015

A conjugated poly(phenyl‐co‐dibenzocyclooctyne) Schiff‐base polymer, prepared through polycondensation of dibenzocyclooctyne bisamine (DIBO‐(NH2)2) with bis(hexadecyloxy)phenyldialdehyde, is reported. The resulting polymer, which has a high molecular weight (Mn>30 kDa, Mw>60 kDa), undergoes efficient strain‐promoted alkyne–azide cycloaddition reactions with a series of azides. This enables quantitative modification of each repeat unit within the polymer backbone and the rapid synthesis of a conjugated polymer library with widely different substituents but a consistent degree of polymerization (DP). Kinetic studies show a second‐order reaction rate constant that is consistent with monomeric dibenzocyclooctynes. Grafting with azide‐terminated polystyrene and polyethylene glycol monomethyl ether chains of varying molecular weight resulted in the efficient syntheses of a series of graft copolymers with a conjugated backbone and maximal graft density.
Multifunctional coatings created using an antimicrobial polymer as a platform for titania precipitation on cotton
Authors: Lum June S. , Salinas Stephen S. , Filocamo Shaun F.
Published: December 2015

Titania precipitation on cotton has been achieved using a commercially available antimicrobial polymer, Reputex 20. The cotton swatches precipitated with titania retain antimicrobial activity, and we have also shown the ability to encapsulate diisopropylfluorophosphatase (DFPase), an enzyme capable of breaking down organofluorophosphates. Cotton swatches are easily prepared and precipitation occurs at room temperature in aqueous solutions at neutral pH. Both the antimicrobial properties of Reputex 20 and the hydrolytic activity of the DFPase enzyme are retained after titania precipitation, generating a cotton material exhibiting multifunctional properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43199.
Preparation and characterization of pH responsive poly(methacrylic acid‐acrylamide‐N‐hydroxyethyl acrylamide) hydrogels for drug delivery systems
Authors: Bal Ayça , Özkahraman Bengi , Özbaş Zehra
Published: December 2015

In this study, pH responsive polymers composed of methacrylic acid, acrylamide, and N‐hydroxyethyl acrylamide were synthesized by free radical polymerization technique. The characterization was done with Fourier transform infrared spectroscopy and scanning electron microscopy. The swelling and drug release behavior of the hydrogels was determined as a function of time at 37°C in pH 2.1 and 7.4. The swelling and drug release studies showed that increased methacrylic acid amount caused a higher increase in swelling and drug release values at pH 7.4 than those at pH 2.1. In addition, the drug release data were applied to kinetic models such as zero order, first order, and Higuchi equations, and it fit well in the Higuchi model of the hydrogel. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43226.
Consensus in second‐order Markovian jump multi‐agent systems via impulsive control using sampled information with heterogenous delays
Authors: Yi Jing‐Wen , Wang Yan‐Wu , Xiao Jiang‐Wen , Chen Yang
Published: December 2015

This paper investigates the consensus problem of second‐order Markovian jump multi‐agent systems with delays. Both network‐induced random delay and node‐induced state delay are considered, where the network‐induced random delay, subjected to a Markov chain, exists in the switching signal and the node‐induced state delay, related to switching topologies, is heterogeneous between any two linked agents. In order to reduce communication and control energy, an impulsive protocol is proposed, where each agent only can get delayed relative positions to neighbors and the velocity of itself at impulsive instants. By performing three steps of model transformation and introducing a mapping for two independent Markov chains, the consensus problem of the original continuous‐time system is equivalent to the stability problem of a discrete‐time expand error system with two Markovian jumping parameters and a necessary and sufficient criterion is derived. A numerical example is given to illustrate the effectiveness of the theoretical result.@@@@This work is supported by the National Natural Science Foundation of China under Grants 61374171, 61572210, and 51537003, the Fundamental Research Funds for the Central Universities (2015TS030), and the Program for Changjiang Scholars and Innovative Research Team in University (IRT1245).
Optimal Control and Synchronization of Alternated Julia Sets
Authors: Wang Pei , Liu Shutang
Published: December 2015

In this paper, spatial‐alternated Julia sets are discussed, which are obtained by alternating the spatial‐alternated system, and plane‐alternated Julia sets are discussed, which are obtained by alternating the plane‐alternated system. The control of spatial‐alternated Julia sets and plane‐alternated Julia sets is achieved via the optimal control. Moreover, the synchronization of two different plane‐alternated Julia sets is implemented via the optimal control. The simulations illustrate the effectiveness of the control method.
Interdecadal change of the active‐phase summer monsoon in East Asia (Meiyu) since 1979
Authors: Wang S.‐Y. Simon , Lin Yen‐Heng , Wu Chi‐Hua
Published: December 2015

The timing of active‐phase East Asian summer monsoon (Meiyu) undergoes a marked shift since 1979. Diagnostic analysis indicates that active convection over Taiwan has occurred later in the season, from late May to early June, with a tendency of increasingly intense rainfall. This timing shift of convection results from a southward migration of Meiyu rainband, driven by an upper‐level cyclonic anomaly over eastern China and a lower‐level anticyclonic anomaly in the subtropical Western Pacific. Together, these two circulation patterns enhance both the moisture transport and baroclinic forcing. The role of Western Pacific warming and anthropogenic greenhouse gases in these changes is suggested.
Sensitive and selective turn‐on fluorescence method for cetyltrimethylammonium bromide determination based on acridine orange–polystyrene sulfonate complex
Authors: Li Na , Hao Xia , Kang Bei Hua , Li Nian Bing , Luo Hong Qun
Published: December 2015

This work proposed a rapid and novel fluorescence‐sensing system using a complex of acridine orange (AO) and polystyrene sulfonate (PSS) to sensitively recognize and monitor cetyltrimethylammonium bromide (CTAB) in an aqueous medium. AO can interact with PSS and a complex is formed via electrostatic attraction and hydrophobic interaction. The fluorescence of AO is greatly quenched after the introduction of PSS. Upon its subsequent addition, CTAB can interact and form a complex with PSS because the electrostatic attraction between CTAB and PSS is much stronger than that between AO and PSS, which results in significant fluorescence recovery. Interestingly, the proposed method can be applied for the discrimination and detection of surfactants with different hydrocarbon chain lengths due to their different binding affinity toward PSS. The detection limit for CTAB is as low as 0.2 µg/mL and the linear range is from 0.5 to 3.5 µg/mL. Moreover, we applied the sensor to the successful detection of CTAB in water samples. Copyright © 2015 John Wiley & Sons, Ltd.
Boden – ein unterschätzter Lebensraum
Authors: Xylander Willi , Lehmitz Ricarda , Hohberg Karin , Lang Birgit , Russell David J.
Published: December 2015

Der Boden ist einer der individuen‐ und artenreichsten Lebensräume der Erde und Ort vielfältiger ökosystemarer Dienstleistungen. Aktuelle Forschungsprojekte zur Entstehung und Entwicklung von Bodentiergemeinschaften, zu den vielfältigen Wechselwirkungen innerhalb des Bodennahrungsnetzes und zur Verbreitung von Bodentieren geben unter anderem Einblick in die ökologischen Ansprüche und Anpassungsfähigkeit der Welt unter unseren Füßen und tragen so dazu bei, eine nachhaltige Nutzung der Ökoressource Boden zu gewährleisten.