bluuebunny/crossref_metadata_2025 huggingface dataset:
A numerical process study on the rapid transport of stratospheric air down to the surface over western North America and the Tibetan Plateau
Authors: Škerlak Bojan , Pfahl Stephan , Sprenger Michael , Wernli Heini
Published: December 2018

Abstract. Upper-level fronts are often associated with the rapid transport of stratospheric air along tilted isentropes to the middle or lower troposphere, there leading to significantly enhanced ozone concentrations. Only occasionally these plumes of originally stratospheric air can be observed at the surface, because (i) stable boundary layers prevent an efficient vertical transport down to the surface, and (ii) if boundary layer turbulence is strong enough to enable this transport, the originally stratospheric air mass is strongly diluted by mixing such that only a weak stratospheric signal can be recorded at the surface. Most documented examples of stratospheric air reaching the surface are from mountainous regions. This study investigates two such events, using a passive stratospheric air mass tracer in a mesoscale model to explore the processes that enable the transport down to the surface. The events occurred in early May 2006 in the Rocky Mountains and in mid June 2006 on the Tibetan Plateau. In both cases, a tropopause fold associated with an upper-level front enabled stratospheric air to enter the troposphere. In our model simulation of the North American case, the strong frontal zone reaches down to 700 hPa and leads to a fairly direct vertical transport of the stratospheric tracer along the tilted isentropes to the surface. In the Tibetan Plateau case, however, no near-surface front exists and a reservoir of high stratospheric tracer concentrations forms at 300–400 hPa, without further isentropic descent. Entrainment at the top of the very deep boundary layer (reaching to 300 hPa over the Tibetan Plateau) and turbulence within the boundary layer fosters downward transport of stratospheric air to the surface. Interestingly, despite the strongly differing dynamical processes, stratospheric tracer concentrations at the surface reach peak values of 10–20 % in both cases, corroborating the potential of deep stratosphere-to-troposphere transport events to significantly influence surface ozone concentrations in these regions.
Regional Ionosphere Mapping Using Zero Difference GPS Carrier Phase
Authors: Tawfeek Heba , Sedeek Ahmed , Rabah Mostafa , El-Fiky Gamal
Published: December 2018

Abstract. Ionospheric delay, can be derived from dual frequency GNSS signals, and then converted into the Vertical Total Electron Contents (VTEC) along the signal path. Various models were devised to calculate VTEC. Examples of such models are the polynomial function model and spherical harmonics model. A common hypothesis of these models is that they are constructed based on the assumption that the entire electron content in the ionosphere is concentrated in a single thin shell at a selected height above Earth. The primary goal of the current research to develop an algorithm capable of producing VTEC maps on an hourly basis, using carrier phase observations from dual frequency GPS receiver. The developed algorithm uses a single GPS station (Zero-difference) to map VTEC over a regional area. The carrier phase measurements are much more precise than the code pseudorange measurements, but they contain an ambiguous term. If such ambiguities are fixed, thence the carrier phase measurements become as unambiguous pseudoranges, but accurate at the level of few millimeters. In current research Sequential Least Square Adjustment (SLSA) was considered to fix ambiguity term in carrier phase observations. The proposed algorithm was written using MATLAB and Called (ZDPID). Two GPS stations (ANKR and BSHM) were used from IGS network to evaluate the developed code, VTEC values were estimated over these two stations. Results of the proposed algorithm were compared with the Global Ionosphere Maps (GIMs), which is generally used as a reference. The results show that the mean difference between VTEC from GIM and estimated VTEC at ANKR station is ranging from −2.1 to 3.67 TECU and its RMS is 0.44. The mean difference between VTEC from GIM and estimated VTEC at BSHM station is ranging from −0.29 to 3.65 TECU and its RMS is 0.38. Another three GPS stations in Egypt were used to generate regional ionosphere maps over Nile Delta, Egypt. The mean differences between VTEC from GIM and estimated VTEC at SAID station is ranging from −1.1 to 3.69 TECU and its RMS is 0.37, from −1.29 to 3.27 TECU for HELW station with RMS equal 0.39, and from 0.2 to 4.2 TECU for BORG station with RMS equal 0.46. Therefore, the proposed algorithm can be used to estimate VTEC efficiently.
Coupled Ca and inorganic carbon uptake suggested by magnesium and sulfur incorporation in foraminiferal calcite
Authors: van Dijk Inge , Barras Christine , de Nooijer Lennart Jan , Mouret Aurélia , Geerken Esmee , Oron Shai , Reichart Gert-Jan
Published: December 2018

Abstract. Shell chemistry of foraminiferal carbonate proves to be useful in reconstructing past ocean conditions. A new addition to the proxy toolbox is the ratio of sulfur (S) to calcium (Ca) in foraminiferal shells, reflecting the ratio of SO42− to CO32− in seawater. When comparing species, the amount of SO42− incorporated, and therefore the S/Ca of the shell, increases with increasing magnesium (Mg) content. The uptake of SO42− in foraminiferal calcite is likely coupled to carbon uptake, while the incorporation of Mg is more likely related to Ca uptake since this element substitutes Ca in the crystal lattice. The relation between S and Mg incorporation in foraminiferal calcite therefore offers the opportunity to investigate the timing of processes involved in Ca and carbon uptake. To understand how foraminiferal S/Ca is related to Mg/Ca, we analyzed the concentration and within-shell distribution of S/Ca of three benthic species with different shell chemistry: Ammonia tepida, Bulimina marginata and Amphistegina lessonii. Furthermore, we investigated the link between Mg/Ca and S/Ca across species and the potential influence of temperature on foraminiferal S/Ca. We observed that S/Ca is positively correlated with Mg/Ca on microscale within specimens, as well as between and within species. In contrast, when shell Mg/Ca increases with temperature, foraminiferal S/Ca values remain similar. We evaluate our findings in the light of previously proposed biomineralization models and abiological processes involved during calcite precipitation. Although all kinds of processes, including crystal lattice distortion and element speciation at the site of calcification, may contribute to changes in the amount of S and Mg that is ultimately incorporated in foraminiferal calcite, these processes do not explain the consistent co-variation between Mg/Ca and S/Ca values. We observe that groups of foraminifera with different calcification pathways, e.g. hyaline versus porcelaneous species, show characteristic values for S/Ca and Mg/Ca, which might be linked to a different calcium and carbon uptake mechanism in porcelaneous and hyaline foraminifera. Whereas Mg incorporation is linked to the Ca-pump, S is linked to carbonate ion concentration via proton pumping. The fact that we observe coupled behavior of S and Mg, within specimens and between species suggests that proton pumping and Ca pumping are intrinsically coupled across scales.
Spatial variability of mean daily estimates of actual evaporation from remotely sensed imagery and surface reference data
Authors: Armstrong Robert N. , Pomeroy John W. , Martz Lawrence W.
Published: December 2018

Abstract. Land surface evaporation has considerable spatial variability that is not captured by point scale estimates calculated from meteorological data alone. Knowing how evaporation varies spatially remains an important issue for improving parameterisations of land surface schemes and hydrological models, and various land management practices. Satellite-based and aerial remote sensing has been crucial for capturing moderate to larger scale surface variables to indirectly estimate evaporative fluxes. However, more recent advances for field research via unmanned aerial vehicles (UAVs) now allows for the acquisition of more highly detailed surface data. Integrating models that can estimate actual evaporation from higher resolution imagery and surface reference data would be valuable to better examine potential impacts of local variations in evaporation on upscaled estimates. This study introduces a novel approach for computing a normalised index from surface variables that can be used to obtain more realistic distributed estimates of actual evaporation. For demonstration purposes the Granger and Gray evaporation model (G–D) was applied at a complex parkland site in central Saskatchewan, Canada. Visible and thermal images and meteorological reference data required to parameterise the model was obtained at midday. Normalised indexes (simple ratios) were computed at midday for albedo and net radiation. This allowed for single measured values albedo and mean daily net radiation to be scaled across high resolution images over a large study region. Albedo and net radiation estimates were within 5–10 % of measured values. An evaporation estimate for a grassed surface was 0.5 mm larger than eddy covariance measurements. The methods applied have two key advantages for estimating evaporation over previous remote sensing approaches, 1. Detailed daily estimates of actual evaporation were directly obtained using a physically-based evaporation model, and 2. Analysis of more detailed and reliable evaporation estimates may lead to improved methods for upscaling evaporative fluxes to larger scales.
Structural weakening of the Merapi dome identified by drone photogrammetry after the 2010 eruption
Authors: Darmawan Herlan , Walter Thomas R. , Troll Valentin R. , Budi-Santoso Agus
Published: December 2018

Abstract. Lava domes are subjected to structural weakening that can lead to
gravitational collapse and produce pyroclastic flows that may travel up to
several kilometers from a volcano's summit. At Merapi volcano, Indonesia,
pyroclastic flows are a major hazard, frequently causing high numbers of
casualties. After the Volcanic Explosivity Index 4 eruption in 2010, a new lava dome developed on
Merapi volcano and was structurally destabilized by six steam-driven
explosions between 2012 and 2014. Previous studies revealed that the
explosions produced elongated open fissures and a delineated block in the
southern dome sector. Here, we investigated the geomorphology, structures,
thermal fingerprint, alteration mapping and hazard potential of the Merapi
lava dome by using drone-based geomorphologic data and forward-looking
thermal infrared images. The block on the southern dome of Merapi is
delineated by a horseshoe-shaped structure with a maximum depth of 8 m and it
is located on the unbuttressed southern steep flank. We identify intense
thermal, fumarole and hydrothermal alteration activities along this
horseshoe-shaped structure. We conjecture that hydrothermal alteration may
weaken the horseshoe-shaped structure, which then may develop into a failure
plane that can lead to gravitational collapse. To test this instability
hypothesis, we calculated the factor of safety and ran a numerical model of
block-and-ash flow using Titan2D. Results of the factor of safety analysis
confirm that intense rainfall events may reduce the internal friction and
thus
gradually destabilize the dome. The titan2D model suggests that a
hypothetical gravitational collapse of the delineated unstable dome sector
may travel southward for up to 4 km. This study highlights the
relevance of gradual structural weakening of lava domes, which can influence
the development fumaroles and hydrothermal alteration activities of cooling
lava domes for years after initial emplacement.
Formation of linear planform chimneys controlled by preferential hydrocarbon leakage and anisotropic stresses in faulted fine-grained sediments, offshore Angola
Authors: Ho Sutieng , Hovland Martin , Blouet Jean-Philippe , Wetzel Andreas , Imbert Patrice , Carruthers Daniel
Published: December 2018

Abstract. A new type of gas chimney exhibiting an unconventional linear planform is found. These chimneys are termed Linear Chimneys, which have been observed in 3-D seismic data offshore of Angola. Linear Chimneys occur parallel to adjacent faults, often within preferentially oriented tier-bound fault networks of diagenetic origin (also known as anisotropic polygonal faults, PFs), in salt-deformational domains. These anisotropic PFs are parallel to salt-tectonic-related structures, indicating their submission to horizontal stress perturbations generated by the latter. Only in areas with these anisotropic PF arrangements do chimneys and their associated gas-related structures, such as methane-derived authigenic carbonates and pockmarks, have linear planforms. In areas with the classic isotropic polygonal fault arrangements, the stress state is isotropic, and gas expulsion structures of the same range of sizes exhibit circular geometry. These events indicate that chimney's linear planform is heavily influenced by stress anisotropy around faults. The initiation of polygonal faulting occurred 40 to 80 m below the present day seafloor and predates Linear Chimney formation. The majority of Linear Chimneys nucleated in the lower part of the PF tier below the impermeable portion of fault planes and a regional impermeable barrier within the PF tier. The existence of polygonal fault-bound traps in the lower part of the PF tier is evidenced by PF cells filled with gas. These PF gas traps restricted the leakage points of overpressured gas-charged fluids along the lower portion of PFs, hence controlling the nucleation sites of chimneys. Gas expulsion along the lower portion of PFs preconfigured the spatial organisation of chimneys. Anisotropic stress conditions surrounding tectonic and anisotropic polygonal faults coupled with the impermeability of PFs determined the directions of long-term gas migration and linear geometries of chimneys. Methane-related carbonates that precipitated above Linear Chimneys inherited the same linear planform geometry, and both structures record the timing of gas leakage and palaeo-stress state; thus, they can be used as a tool to reconstruct orientations of stress in sedimentary successions. This study demonstrates that overpressure hydrocarbon migration via hydrofracturing may be energetically more favourable than migration along pre-existing faults.
Sullo "ius adipiscendae civitatis Romanae per magistratum" nella "Lex Irnitana"
Authors: Russo Federico
Published: December 2018

Il capitolo 21 della Lex Irnitana stabilisce il diritto per gli ex magistrati del municipio che fossero anche decurioni di acquisire la cittadinanza romana allo scadere del loro incarico, insieme a parte dei loro familiari. Un’approfondita analisi del testo ha rivelato che esso, nel contempo e seppur indirettamente, determina anche i casi in cui tale diritto non si applicava. La lettura di altri capitoli della Lex di Irni come di alcuni passi della Lex della colonia di Urso ha permesso di meglio definire quelle situazioni in cui lo ius adipiscendae civitatis Romanae per magistratum, pure atteso, non avrebbe potuto trovare applicazione.
El gobernador provincial y las comunidades latinas: el caso de "Nemausus" en Estrabón
Authors: Olmo López Rubén
Published: December 2018

Propongo una nueva interpretación de Estrabón 4.1.12 y 4.6.4. En base a estos textos ambiguos se ha planteado la hipótesis de que Nemausus no estaría sometida a las órdenes del gobernador de la Narbonense. Sin embargo, no se conoce ninguna comunidad latina independiente de la jurisdicción del gobernador provincial y no existen indicios que prueben que Nemausus gozaba de un privilegio especial. Las frases de Estrabón se refieren a las 24 komai dependientes de Nemausus y es posible explicarlas dentro del marco institucional romano.
La onomástica de los "Latini Iuniani": una primera aproximación
Authors: López Barja de Quiroga Pedro
Published: December 2018

Aquí se compilan todas las referencias que tenemos a Latinos Junianos, en las fuentes literarias, identificados por su nombre, tanto las que son seguras como las menos probables, en el periodo entre Augusto y la dinastía de los Severos. También se lleva a cabo un análisis de los documentos relativos a Venidius Ennychus (Herculano) y, en particular, de algunos casos concretos que conocemos gracias a la epigrafía. La información procedente de Egipto así como las fuentes literarias tardorromanas no serán objeto de atención en este momento.
The Relationship Between Digital Egg Coloration and Egg Survival in Landlocked Fall Chinook
Authors: Robley Holiday , Barnes Michael E.
Published: December 2018

Digital color values were collected from the eggs of 128 spawns from individual landlocked fall Chinook salmon Oncorhynchus tshawytscha females from Lake Oahe, South Dakota, USA, in 2008, 2009, 2015 and 2016. For all spawns, the mean (SE) a* value, a measure of red-green chromaticness, was 10.99 (0.27), and ranged from 3.98 to 18.71. Mean (SE) b* (yellow-green) was 20.27 (0.32), and ranged from 9.28 to 28.50. Mean (SE) L* (white-black) was 20.73 (0.48), and ranged from 3.98 to 18.71. Egg total color index also showed considerable variation, with a mean (SE) of 23.05 (0.37) and range from 11.70 to 31.64. Egg survival to the eyed-stage was weakly, but significantly, correlated to b* (r = 0.206), L* (r = 0.185), Chroma (r = 0.211), and Entire Color Index (r = 0.211). Spawns with no egg survival had eggs with significantly lower a* values compared to spawns where at least some of the eggs survived to the eyed stage. L*, a*, b*, Chroma, and Entire Color Index varied significantly among the years, but Hue and egg survival to the eyed stage did not. The results of this study indicate a possible link between egg color and landlocked fall Chinook salmon egg survival, possibly due to differences in the diets of feral broodstock females or their ability to deposit bodily carotenoids in the developing eggs.
Components of Procurement Reforms That Influence Expenditure Management in Secondary Schools in Kenya: A Focus on Tender Advertising
Authors: Kibinu Kinuthia Eric , Odundo Paul A. , Nyagah Grace
Published: December 2018

In Kenya, the public procurement sector has developed over the past 5 decades, from a system with no regulations to a system regulated by circulars; and currently, to a system firmly grounded on sound laws and policies. The aim of this study was to establish the extent to which public secondary schools in Nairobi City County had complied with relevant legislative and policy provisions guiding procurement reforms, as well as the effect of selected  of reforms on expenditure management. This article focuses on the frequency of tender advertising. The evaluation research model III was applied to guide the research process and primary data were sourced in 2015 from 35 public secondary schools. Quantitative analysis included cross-tabulation with analysis of variance, chi-square statistic, correlation coefficient, as well as multiple regression. The study found that two-thirds of the schools were consistently advertising tenders as required by the legislative and policy provisions. Besides, the frequency of tender advertising significantly correlated with variation in procurement expenditure; and further caused a significant reduction in the same (beta weight = -0.335, t-statistic = -2.639 & ρ-value = 0.014), which signifies a positive influence on expenditure management. Ensuring consistency in advertising tenders is likely to help many schools improve on expenditure management; thereby, enhance the contribution of public procurement to national development.
Experimentally and Numerically Analyzed Piezoelectric Characteristics of PZT Ceramics
Authors: Yang Lale , Nagano Hirokazu , Okayasu Mitsuhiro
Published: December 2018

The electric generation characteristics of the PZT piezoelectric ceramics were examined experimentally and numerically. In this case, cyclic bending loading was applied to the PZT ceramics: bulk and thin-film membrane. Electric voltage increased with increasing the strain value. There was a sharp initial increase in positive voltage for the PZT ceramics as bending load was applied. Following this initial increase stage, a rapid fall to zero occurred. The reduction rate of the positive voltage was changed depending on the rigidly of the PZT ceramic: the higher the reduction rate, the higher the rigid of the ceramic. The electrical voltage from the circular membrane PZT ceramic during cyclic loading showed the higher level compared to that for the bulk one, in which the flexibility of the PZT ceramic was significant factor to obtain the high electric voltage. The variation of the electric voltages was estimated numerically, which was relatively in good agreement with the experimental one.
Is a Wetter Grid a Greener Grid? Estimating Emissions Offsets for Wind and Solar Power in the Presence of Large Hydroelectric Capacity
Authors: Castro Miguel
Published: December 2018

I use random fluctuations in hourly wind and solar generation in California to estimate how much they reduce emissions of carbon dioxide, sulfur dioxide, and nitrogen oxides. These offsets depend on the direct displacement of high-cost natural gas generators, and on the hydropower reallocation that occurs to the hours with the lowest increase in renewable generation. Solar power daily intermittency shifts hydro from the afternoon to the evening, which increases its emissions offsets since the gas generators displaced in the evening are dirtier than those kept running in the afternoon. In contrast, wind offsets are less sensitive to hydropower reallocation, since it leads to a substitution of generators with similar emissions intensities. These findings highlight the importance of accounting for interactions between wind, solar, and hydro capacity in assessing their environmental benefits. Similar lessons will apply to electric grids with storage capacity.
Short- to Mid-term Day-Ahead Electricity Price Forecasting Using Futures
Authors: Steinert Rick , Ziel Florian
Published: December 2018

Due to the liberalization of markets, the change in the energy mix and the surrounding energy laws, electricity research is a dynamically altering field with steadily changing challenges. One challenge especially for investment decisions is to provide reliable short to mid-term forecasts despite high variation in the time series of electricity prices. This paper tackles this issue in a promising and novel approach. By combining the precision of econometric autoregressive models in the short-run with the expectations of market participants reflected in future prices for the short- and mid-run we show that the forecasting performance can be vastly increased while maintaining hourly precision. We investigate the day-ahead electricity price of the EPEX Spot for Germany and Austria and setup a model which incorporates the Phelix future of the EEX for Germany and Austria. The model can be considered as an AR24-X model with one distinct model for each hour of the day. We are able to show that future data contains relevant price information for future time periods of the day-ahead electricity price. We show that relying only on deterministic external regressors can provide stability for forecast horizons of multiple weeks. By implementing a fast and efficient lasso estimation approach we demonstrate that our model can outperform several other models in the literature.
Enterprise in the economic calculus
of the impact of road investments
Authors: Brdulak Jacek , Pawlak Piotr
Published: December 2018

Development of infrastructure results in reduction of costs of transportation. It is a significant factor that influences both supply and demand side of production. By lowering the costs of transportation, production companies benefit, together with transport companies, who lower their own costs and thus they can be more competitive on the market of services. The article contains an analysis of mathematical and statistical methods used to measure and evaluate the effects of road investments. Gravity and potential, index and generated traffic models have been discussed. Assessment of the profitability of the investment and benefits for many has been presented on the example of the construction of 21 km section of a motorway which is a bypass of Mińsk Mazowiecki.
Między poczuciem wyższości cywilizacyjnej a autoidentyfikacją, między rasą a narodem. Polska i Chiny w drugiej połowie XIX wieku
Authors: Kołos Anna
Published: December 2018

The article discusses, on the one hand, three stages of developing views about race and superiority of European civilization reflected in the second half of the 19th century in aggressive social-Darwinism of positivists, and on the other it confronts racial generalizations with nation-centered thinking, which played an extremely important role in identity discourse of the Poles. On the example of China and the Siberian-Chinese borderland, it can be noticed that perception of geography and the ethnic diversity in the world through the prism of great historiosophical and racial constructions is manifested in quite widespread adaptation of orientalizing language of the hegemon speaking about backwardness, lack of maturity for modernization and definite supremacy of Europe, while resistance to the oppression of the partitioners, and more broadly to the colonial policy of the European powers allows in Poland, contemptuously called Halb-Asien, like in the case of Indians and Boers, creating a kind of auto-colonial identification with the seemingly “exotic” nation.
Dekonstrukcja tożsamości osoby z nabytą dysfunkcją ruchową organizmu – socjologiczna analiza procesu (nie)radzenia sobie z niepełnosprawnością
Authors: Niedbalski Jakub
Published: December 2018

Celem artykułu jest określenie, w jaki sposób powstanie trwałej dysfunkcji organizmu powoduje istotne przemiany w sposobie postrzegania samego siebie przez człowieka dotychczas cieszącego się pełnią władz nad swoim ciałem.
Artykuł porusza kwestie przemian dokonujących się w życiu osoby sprawnej, która w wyniku zdarzenia losowego nabyła niepełnosprawność. W tekście wykazano istniejącą paralelę pomiędzy kryzysem ciała wynikającym z utraty jego pełnej sprawności a kryzysem na poziomie tożsamości, którego objawem są tytułowe sytuacje (nie)radzenia sobie z wejściem w rolę osoby z niepełnosprawnością ruchową. Jednocześnie starano się podkreślić, że nabycie dysfunkcji ciała przyczynia się do zmian sposobu postrzegania siebie samego, co skutkuje dezorganizacją egzystencjalnego ładu i destabilizacją autodefinicji danej osoby.
W badaniach wykorzystane zostały dane jakościowe zdobyte za pomocą techniki pogłębionego wywiadu swobodnego przeprowadzonego wśród osób z niepełnosprawnością ruchową. Analiza i interpretacja materiału badawczego prowadzona była zgodnie z procedurami metodologii teorii ugruntowanej.
Editor's Corner
Authors: Sare Laura
Published: December 2018

This is my first cover I get to select as editor, and I chose my favorite topic—birds! On the cover is a piping plover nest, and here on this page is the adult version. These little shorebirds are entertaining to watch as they run along the beach, often eating worms they pull out of the sand that are longer than they are. I get to see them in Texas when they come down to spend the winter along the Gulf coast. Unfortunately regional populations of this bird are listed under the Endangered Species Act as Threatened or Endangered (ecos.fws.gov/ecp0/profile/speciesProfile?spcode=B079).
Reactive oxygen species regulate activity-dependent neuronal plasticity in Drosophila
Authors: Oswald Matthew CW , Brooks Paul S , Zwart Maarten F , Mukherjee Amrita , West Ryan JH , Giachello Carlo NG , Morarach Khomgrit , Baines Richard A , Sweeney Sean T , Landgraf Matthias
Published: December 2018

Reactive oxygen species (ROS) have been extensively studied as damaging agents associated with ageing and neurodegenerative conditions. Their role in the nervous system under non-pathological conditions has remained poorly understood. Working with the Drosophila larval locomotor network, we show that in neurons ROS act as obligate signals required for neuronal activity-dependent structural plasticity, of both pre- and postsynaptic terminals. ROS signaling is also necessary for maintaining evoked synaptic transmission at the neuromuscular junction, and for activity-regulated homeostatic adjustment of motor network output, as measured by larval crawling behavior. We identified the highly conserved Parkinson’s disease-linked protein DJ-1β as a redox sensor in neurons where it regulates structural plasticity, in part via modulation of the PTEN-PI3Kinase pathway. This study provides a new conceptual framework of neuronal ROS as second messengers required for neuronal plasticity and for network tuning, whose dysregulation in the ageing brain and under neurodegenerative conditions may contribute to synaptic dysfunction.
Role of the pre-initiation complex in Mediator recruitment and dynamics
Authors: Knoll Elisabeth R , Zhu Z Iris , Sarkar Debasish , Landsman David , Morse Randall H
Published: December 2018

The Mediator complex stimulates the cooperative assembly of a pre-initiation complex (PIC) and recruitment of RNA Polymerase II (Pol II) for gene activation. The core Mediator complex is organized into head, middle, and tail modules, and in budding yeast (Saccharomyces cerevisiae), Mediator recruitment has generally been ascribed to sequence-specific activators engaging the tail module triad of Med2-Med3-Med15 at upstream activating sequences (UASs). We show that yeast lacking Med2-Med3-Med15 are viable and that Mediator and PolII are recruited to promoters genome-wide in these cells, albeit at reduced levels. To test whether Mediator might alternatively be recruited via interactions with the PIC, we examined Mediator association genome-wide after depleting PIC components. We found that depletion of Taf1, Rpb3, and TBP profoundly affected Mediator association at active gene promoters, with TBP being critical for transit of Mediator from UAS to promoter, while Pol II and Taf1 stabilize Mediator association at proximal promoters.
Eigil Reimers; Våre Hjortedyr – en bok til undring, glede og kunnskap
Authors: Wiklund Eva
Published: December 2018

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Short-term interval aerobic exercise training does not improve memory functioning in relapsing-remitting multiple sclerosis—a randomized controlled trial
Authors: Baquet Lisa , Hasselmann Helge , Patra Stefan , Stellmann Jan-Patrick , Vettorazzi Eik , Engel Andreas K. , Rosenkranz Sina Cathérine , Poettgen Jana , Gold Stefan Michael , Schulz Karl-Heinz , Heesen Christoph
Published: December 2018

Background

Only few aerobic exercise intervention trials specifically targeting cognitive functioning have been performed in multiple sclerosis.

Objective and Methods

This randomized controlled trial with 34 patients in the intervention group (IG) (mean: 38.2 years (±9.6)) and 34 patients in the control group (CG) (mean: 39.6 years (±9.7)) aimed to determine the effects of aerobic exercise on cognition in relapsing-remitting multiple sclerosis (RRMS). The primary outcome was verbal learning assessed by the verbal learning and memory test (VLMT). Patients were randomized to an IG or a waitlist CG. Patients in the IG exercised according to an individually tailored training schedule (with two to three sessions per week for 12 weeks). The primary analysis was carried out using the intention-to-treat (ITT) sample with ANCOVA adjusting for baseline scores.

Results

A total of 77 patients with RRMS were screened and 68 participants randomized (CG n = 34; IG n = 34). The sample comprised 68% females, had a mean age of 39 years, a mean disease duration of 6.3 years, and a mean expanded disability status scale of 1.8. No significant effects were detected in the ITT analysis for the primary endpoint VLMT or any other cognitive measures. Moreover, no significant treatment effects were observed for quality of life, fatigue, or depressive symptoms.

Conclusion

This study failed to demonstrate beneficial effects of aerobic exercise on cognition in RRMS. The trial was prospectively registered at clinicaltrials.gov (NCT02005237).
Diazaphospholene Chemistry
Authors: Gudat Dietrich
Published: December 2018

Diazaphospholenes are N‐heterocyclic phosphines that can be derived from N‐heterocyclic carbenes by formally replacing the divalent carbon atom by a P–X unit consisting of a tervalent phosphorus atom and an exocyclic substituent X. This arrangement provides a very peculiar electronic structure that is characterized by an exceptionally strong hyperconjugation between delocalized π‐electrons in the ring and the σ*(P–X) orbital and results in a considerable ionic polarization of the exocyclic bond with a concomitant increase of negative partial charge on X. The effect persists even in unpolar P–X bonds and induces unprecedented chemical reactivity like a marked polarization of homonuclear bonds to phosphorus‐based substituents, which immensely facilitates bond activation reactions, and a reversal of the polarity (“Umpolung”) of the P–H bonds in secondary diazaphospholenes, which gives rise to a hydride behavior unprecedented for phosphines. The emerging exploitation of these features in diverse areas of synthetic chemistry sparked various applications of diazaphospholenes both as stoichiometric reagents and as organocatalysts. It is the aim of this article to give a comprehensive overview on the chemistry of diazaphospholenes, starting with a discussion of their specific electronic structure, and addressing their synthesis, principal reaction patterns, and applications as reagents in stoichiometric reactions and organocatalysts in metal‐free catalytic transformations. A concluding section will focus on ligand‐centered reactions of diazaphospholenes with exocyclic transition metal substituents (“metallo‐diazaphospholenes”) and their application in catalysis.
Competition between Exceptionally Long‐Range Alkyl Sidechain Ordering and Backbone Ordering in Semiconducting Polymers and Its Impact on Electronic and Optoelectronic Properties
Authors: Carpenter Joshua H. , Ghasemi Masoud , Gann Eliot , Angunawela Indunil , Stuard Samuel J. , Rech Jeromy James , Ritchie Earl , O'Connor Brendan T. , Atkin Joanna , You Wei , DeLongchamp Dean M. , Ade Harald
Published: December 2018

Intra‐ and intermolecular ordering greatly impacts the electronic and optoelectronic properties of semiconducting polymers. The interrelationship between ordering of alkyl sidechains and conjugated backbones has yet to be fully detailed, despite much prior effort. Here, the discovery of a highly ordered alkyl sidechain phase in six representative semiconducting polymers, determined from distinct spectroscopic and diffraction signatures, is reported. The sidechain ordering exhibits unusually large coherence lengths (≥70 nm), induces torsional/twisting backbone disorder, and results in a vertically multilayered nanostructure with ordered sidechain layers alternating with disordered backbone layers. Calorimetry and in situ variable temperature scattering measurements in a model system poly{4‐(5‐(4,8‐bis(3‐butylnonyl)‐6‐methylbenzo[1,2‐b:4,5‐b′]dithiophen‐2‐yl)thiophen‐2‐yl)‐2‐(2‐butyloctyl)‐5,6‐difluoro‐7‐(5‐methylthiophen‐2‐yl)‐2H‐benzo[d][1,2,3]triazole} (PBnDT‐FTAZ) clearly delineate this competition of ordering that prevents simultaneous long‐range order of both moieties. The long‐range sidechain ordering can be exploited as a transient state to fabricate PBnDT‐FTAZ films with an atypical edge‐on texture and 2.5× improved field‐effect transistor mobility. The observed influence of ordering between the moieties implies that improved molecular design can produce synergistic rather than destructive ordering effects. Given the large sidechain coherence lengths observed, such synergistic ordering should greatly improve the coherence length of backbone ordering and thereby improve electronic and optoelectronic properties such as charge transport and exciton diffusion lengths.
Light Emitting Diodes Based on Inorganic Composite Halide Perovskites
Authors: Lian Xiujun , Wang Xi , Ling Yichuan , Lochner Eric , Tan Lei , Zhou Yan , Ma Biwu , Hanson Kenneth , Gao Hanwei
Published: December 2018

CsPbBr3 is a promising type of light‐emitting halide perovskite with inorganic composition and desirable thermal stability. The luminescence efficiency of pristine CsPbBr3 thin films, however, appears to be limited. In this work, light emitting diodes based on CsPbBr3|Cs4PbBr6 composites are demonstrated. Both quantum efficiency and emission brightness are improved significantly compared with similar devices constructed using pure CsPbBr3. The high brightness can be attributed to the enhanced radiative recombination from CsPbBr3 crystallites confined in the Cs4PbBr6 host matrix. The unfavorable charge transport property of Cs4PbBr6 can be circumvented by optimizing the ratio between the host and the guest components and the total thickness of the composite thin films. The inorganic composition of the emitting layer also leads to improved device stability under the condition of continuous operation.
Recent Advances in the Functional 2D Photonic and Optoelectronic Devices
Authors: Wang Xiaoting , Cui Yu , Li Tao , Lei Ming , Li Jingbo , Wei Zhongming
Published: December 2018

2D layered materials such as graphene, black phosphorus (BP), transition metal dichalcogenides (TMDCs), and their hybrid systems exhibit wide coverage of bandgaps, unique crystal structures, and the facile integration for potential applications in photonic and optoelectronic devices. In the recent two years, various 2D functional systems have been developed with novel optoelectronic properties, thereby expanding the functional applications. Beyond the speed, efficiency, or sensitivity, these 2D crystals can offer additional advantages and distinct applications in terms of spectrum range, polarization, intensity, and structural designs. The main contents here focus on optoelectronic and photonic devices with unique functional applications, especially mentioning areas as follows: long‐wavelength photodetector, 2D polarization‐sensitive photodetector, 2D optoelectronic memory, and 2D material‐based optical modulator. For each section, the device design, performance, and operational principles are investigated and systematically discussed. Finally, the current research status is summarized and perspectives on possible applications in future are offered.
Palladium/Acid Relay Catalyzed Tandem Heck Coupling/6‐Endo Cyclization between ortho‐Halogenated Benzoates and Unactivated Terminal Alkenes for the Synthesis of 1‐Isochromanones
Authors: Wen Zhen‐Kang , Ge Xiao‐Min , Zhao Ze‐Kai , Chao Jian‐Bin
Published: December 2018

We report a unique and expeditious route to synthesize 1‐isochromanone derivatives through palladium catalyzed tandem Heck coupling/6‐endo hydroacyloxylation cyclization between readily available ortho‐halogenated benzoates and unactivated alkenes. Various 2‐bromo or 2‐iodo benzoates can be coupled efficiently with a broad range of alkenes to afford functionalized 1‐isochromanones in high yields. Significantly, this cost‐efficient and easy‐to‐handle synthetic methodology will have great prospect application in the synthetic and medicinal chemistry.

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Efficient Near Infrared Light Triggered Nitric Oxide Release Nanocomposites for Sensitizing Mild Photothermal Therapy
Authors: Zhang Xiao , Du Jiangfeng , Guo Zhao , Yu Jie , Gao Qin , Yin Wenyan , Zhu Shuang , Gu Zhanjun , Zhao Yuliang
Published: December 2018

Mild photothermal therapy (PTT), as a new anticancer therapeutic strategy, faces big challenges of limited therapeutic accuracy and side‐effects due to uneven heat distribution. Here, near infrared triggered nitric oxide (NO) release nanocomposites based on bismuth sulfide (Bi2S3) nanoparticles and bis‐N‐nitroso compounds (BNN) are constructed for NO‐enhanced mild photothermal therapy. Upon 808 nm irradiation, the high photothermal conversion efficiency and on‐demand NO release are realized simultaneously. Due to the unique properties of NO, enhanced antitumor efficacy of mild PTT based on BNN‐Bi2S3 nanocomposites is achieved in vitro and in vivo. Mechanism studies reveal that the exogenous NO from BNN‐Bi2S3 could not only impair the autophagic self‐repairing ability of tumor cells in situ, but also diffuse to the surrounding cells to enhance the therapeutic effect. This work points out a strategy to overcome the difficulties in mild PTT, and has potentials for further exploitation of NO‐sensitized synergistic cancer therapy.
Insights into the Epidemiology, Pathogenesis, and Therapeutics of Nonalcoholic Fatty Liver Diseases
Authors: Yu Yao , Cai Jingjing , She Zhigang , Li Hongliang
Published: December 2018

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease which affects ≈25% of the adult population worldwide, placing a tremendous burden on human health. The disease spectrum ranges from simple steatosis to steatohepatitis, fibrosis, and ultimately, cirrhosis and carcinoma, which are becoming leading reasons for liver transplantation. NAFLD is a complex multifactorial disease involving myriad genetic, metabolic, and environmental factors; it is closely associated with insulin resistance, metabolic syndrome, obesity, diabetes, and many other diseases. Over the past few decades, countless studies focusing on the investigation of noninvasive diagnosis, pathogenesis, and therapeutics have revealed different aspects of the mechanism and progression of NAFLD. However, effective pharmaceuticals are still in development. Here, the current epidemiology, diagnosis, animal models, pathogenesis, and treatment strategies for NAFLD are comprehensively reviewed, emphasizing the outstanding breakthroughs in the above fields and promising medications in and beyond phase II.
Semiconducting Polymer Thin Films Used in Organic Solar Cells: A Scanning Tunneling Microscopy Study
Authors: Caballero‐Quintana Irving , Maldonado José‐Luis , Meneses‐Nava Marco‐Antonio , Barbosa‐García Oracio , Valenzuela‐Benavides José , Bousseksou Azzedine
Published: December 2018

The widely used semiconducting polymers poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) (PH1000), poly(3‐hexylthiophene‐2,5‐diyl) (P3HT), and Poly[[4,8‐bis[(2‐ethylhexyl)oxy]benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl][3‐fluoro‐2‐[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl]] (PTB7) for organic photovoltaic (OPV) cells, are deposited on highly ordered pyrolytic graphite substrates and investigated by scanning tunneling microscopy (STM) under the liquid/solid interface technique. PEDOT:PSS film morphology shows an ellipsoidal shape of PEDOT surrounded by PSS with 4 nm size. STM images of P3HT reveal that films tend to form well‐defined crystalline domains with an average interchain distance around 1.41 nm and chain length ≈41 nm. PTB7 chains are self‐aggregated by using chlorobenzene as solvent; however, when using 1‐phenyloctane with 3% of 1,8‐diiodooctane, these chains show a worm‐like pattern with a distance of ≈2 nm between backbone chains and a chain length of ≈90 nm. For P3HT and PTB7 based OPVs, local J–V plots are determined from photoconductive atomic force microscopy (pc‐AFM) measurements and fitted with the modified Mott−Gurney equation, the reached parameters are correlated with those achieved from the macroscopic J–V graphs. Active films of OPVs cells based on PTB7 are also analyzed by using AFM phase imaging showing domains size of 80–120 nm. This current STM analysis can elucidate some new important insights on polymer film formation and morphology and therefore, their influence on the OPV performance.
Novel variants in SPTAN1 without epilepsy: An expansion of the phenotype
Authors: Gartner Valerie , Markello Thomas C. , Macnamara Ellen , De Biase Andrea , Thurm Audrey , Joseph Lisa , Beggs Alan H. , Schmahmann Jeremy D. , Berry Gerard T. , Anselm Irina , Boslet Emma , Tifft Cynthia J. , Gahl William A. , Lee Paul R.
Published: December 2018

We describe two unrelated children with de novo variants in the non‐erythrocytic alpha‐II‐spectrin (SPTAN1) gene who have hypoplastic brain structures, intellectual disability, and both fine and gross motor impairments. Using agnostic exome sequencing, we identified a nonsense variant creating a premature stop codon in exon 21 of SPTAN1, and in a second patient we identified an intronic substitution in SPTAN1 prior to exon 50 creating a new donor acceptor site. Neither of these variants has been described previously. Although some of these patients' features are consistent with the known SPTAN1 encephalopathy phenotype, these two children do not have epilepsy, in contrast to reports about nearly every other patient with heterozygous SPTAN1 variants and in all patients with a variant near the C‐terminal coding region. Moreover, both children have abnormal thyroid function, which has not been previously reported in association with SPTAN1 variant. We present a detailed discussion of the clinical manifestations of these two unique SPTAN1 variants and provide evidence that both variants result in reduced mRNA expression despite different locations within the gene and clinical phenotypes. These findings expand the motor, cognitive, and behavioral spectrum of the SPTAN1‐associated phenotype and invite speculation about underlying pathophysiologies.
Structural and Optical Properties of Zn1‐xMgxO Prepared by Calcination of ZnO + Mg(OH)2 after Hydro Micro Mechanical Activation
Authors: Vuong Thi Quynh Phuong , Lair Valentin , Lacoste François R. , Halloumi Samy , Coindeau Stéphane , Thiel Julien , Shubina Tatiana V. , Pauthe Monique , Gil Bernard
Published: December 2018

Zn1‐xMgxO microcrystals are produced in the 0.15 ≤ x ≤ 1 composition range by calcination of ZnO + Mg(OH)2 after hydro micro mechanical activation according to the patent WO2018065735A1. The structural properties of the samples have revealed the cohabitation of wurtzite and rock‐salt phases for x values ranging from 0.15 up to 0.6 with a clear increase of the proportion of cubic phase with x. A single cubic phase is observed in the range 0.66 ≤ x < 1. From the purity of these samples produced at very low cost, it is expected that they will be used as precursors for growth of advanced light emitters integrated into an already existing process as they exhibit exceptionally efficient (and robust with T) light emission in the ultraviolet region.
Flocculation of kaolin from aqueous suspension using low dosages of acrylamide‐based cationic flocculants
Authors: Suresha P. R. , Badiger Manohar V.
Published: December 2018

Flocculation of kaolin from aqueous streams has become very important in view of its wide range of applications. In this work, cationic flocculants based on copolymers of acrylamide (AM) and 3‐acrylamidopropyltrimethylammonium chloride (APTMAC) were synthesized with two different mole ratios of monomers, 80 mol % of AM (CP‐8020) and 40 mol % of AM (CP‐4060). The chemical structures of copolymers were confirmed by 1H and carbon‐13 nuclear magnetic resonance (13C NMR) spectroscopy. The molecular weight (MW) and zeta potential of the copolymers were determined. High MW was obtained for copolymer with high content of AM (CP‐8020) and high zeta potential was observed for copolymer with high content of APTMAC (CP‐4060). Flocculation of kaolin suspension was performed using both CP‐8020 and CP‐4060 and the flocculation was correlated to the zeta potential and MW of the copolymers. The optimum dosages of flocculants were determined. The mechanism of flocculation was discussed in terms of charge neutralization and bridging. The flocs of kaolin were characterized in terms of moisture content and size. To the best of our knowledge, this copolymer system was used for the first time for kaolin flocculation and found out to be efficient. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47286.