bluuebunny/crossref_metadata_2025 huggingface dataset:
Trends in emissions and concentrations of air pollutants in the lower troposphere in the Baltimore/Washington airshed from 1997 to 2011
Authors: He H. , Stehr J. W. , Hains J. C. , Krask D. J. , Doddridge B. G. , Vinnikov K. Y. , Canty T. P. , Hosley K. M. , Salawitch R. J. , Worden H. M. , Dickerson R. R.
Published: February 2013

Abstract. Trends in the composition of the lower atmosphere (0–1500 m altitude) and surface air quality over the Baltimore/Washington area and surrounding states were investigated for the period from 1997 to 2011. We examined emissions, ground-level observations and long-term aircraft measurements to characterize trends in air pollution. The USEPA Continuous Emissions Monitoring System (CEMS) program reported substantial decreases in point sources resulting from national and regional control measures; these decreases are definitely reflected in the ground-level observations. The decreasing trend of CO column contents is ~8.0 Dobson Unit (DU) decade−1, corresponding to ~350 ppbv decade−1 in the lower troposphere. Satellite observations of long-term, near-surface CO show ~40% decrease over western Maryland between 2000 and 2011, the same magnitude as indicated by aircraft measurements over upwind regions of Baltimore/Washington aished. After compensating for inter-annual temperature variations, historical aircraft measurements suggest the daily net production of tropospheric ozone over Baltimore/Washington area decreases from ~20 ppbv in the late 1990s to ~7 ppbv in the early 2010s during the ozone season. A decrease in the long-term ozone column content is observed as ~2.0 DU decade−1 in the lowest 1500 m, corresponding to ~13 ppbv decade−1 decrease. Back trajectory cluster analysis demonstrates that emissions of air pollutants from Ohio and Pennsylvania through Maryland influence column contents of downwind ozone in the lower atmosphere. The trends of air pollutants reveal the success of regulations implemented over the last decade and the importance of region wide emission controls over the eastern United States.
GPS observations of medium-scale traveling ionospheric disturbances over Europe
Authors: Otsuka Y. , Suzuki K. , Nakagawa S. , Nishioka M. , Shiokawa K. , Tsugawa T.
Published: February 2013

Abstract. Two-dimensional structures of medium-scale traveling ionospheric disturbances (MSTIDs) over Europe have been revealed, for the first time, by using maps of the total electron content (TEC) obtained from more than 800 GPS receivers of the European GPS receiver networks. From statistical analysis of the TEC maps obtained 2008, we have found that the observed MSTIDs can be categorized into two groups: daytime MSTID and nighttime MSTID. The daytime MSTID frequently occurs in winter. Its maximum occurrence rate in monthly and hourly bin exceeds 70% at lower latitudes over Europe, whereas it is approximately 45% at higher latitudes. Since most of the daytime MSTIDs propagate southward, we speculate that they could be caused by atmospheric gravity waves in the thermosphere. The nighttime MSTIDs also frequently occur in winter but most of them propagate southwestward, in a direction consistent with the theory that polarization electric fields play an important role in generating the nighttime MSTIDs. The nighttime MSTID occurrence rate shows distinct latitudinal difference: The maximum of the occurrence rate in monthly and hourly bin is approximately 50% at lower latitudes in Europe, whereas the nighttime MSTID was rarely observed at higher latitudes. We have performed model calculations of the plasma density perturbations caused by a gravity wave and an oscillating electric field to reproduce the daytime and nighttime MSTIDs, respectively. We find that TEC perturbations caused by gravity waves do not show dip angle dependencies, while those caused by the oscillating electric field have a larger amplitude at lower latitudes. These dip angle dependencies of the TEC perturbation amplitude could contribute to the latitudinal variation of the MSTID occurrence rate. Comparing with previous studies, we discuss the longitudinal difference of the nighttime MSTID occurrence rate, along with the E- and F-region coupling processes. The seasonal variation, of the nighttime MSTID occurrence rate in Europe, is not consistent with the theory that the longitudinal and seasonal variations of the nighttime MSTID occurrence could be attributed to those of the Es layer occurrence.
Simultaneous assimilation of satellite and eddy covariance data for improving terrestrial water and carbon simulations at a semi-arid woodland site in Botswana
Authors: Kato T. , Knorr W. , Scholze M. , Veenendaal E. , Kaminski T. , Kattge J. , Gobron N.
Published: February 2013

Abstract. Terrestrial productivity in semi-arid woodlands is strongly susceptible to changes in precipitation, and semi-arid woodlands constitute an important element of the global water and carbon cycles. Here, we use the Carbon Cycle Data Assimilation System (CCDAS) to investigate the key parameters controlling ecological and hydrological activities for a semi-arid savanna woodland site in Maun, Botswana. Twenty-four eco-hydrological process parameters of a terrestrial ecosystem model are optimized against two data streams separately and simultaneously: daily averaged latent heat flux (LHF) derived from eddy covariance measurements, and decadal fraction of absorbed photosynthetically active radiation (FAPAR) derived from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Assimilation of both data streams LHF and FAPAR for the years 2000 and 2001 leads to improved agreement between measured and simulated quantities not only for LHF and FAPAR, but also for photosynthetic CO2 uptake. The mean uncertainty reduction (relative to the prior) over all parameters is 14.9% for the simultaneous assimilation of LHF and FAPAR, 8.5% for assimilating LHF only, and 6.1% for assimilating FAPAR only. The set of parameters with the highest uncertainty reduction is similar between assimilating only FAPAR or only LHF. The highest uncertainty reduction for all three cases is found for a parameter quantifying maximum plant-available soil moisture. This indicates that not only LHF but also satellite-derived FAPAR data can be used to constrain and indirectly observe hydrological quantities.
Initial Spread of 137Cs over the shelf of Japan: a study using the high-resolution global-coastal nesting ocean model
Authors: Lai Z. , Chen C. , Beardsley R. , Lin H. , Ji R. , Sasaki J. , Lin J.
Published: February 2013

Abstract. The 2011 Tohoku earthquake caused radionuclide 137Cs be directly released into the ocean from the Fukushima Dai-ichi nuclear power plants. A high-resolution global-coastal nesting ocean model was established to simulate the initial spread of 137Cs as conservative tracer over the shelf of Japan after the accident. The major advantage in the current model system is to use unstructured grids to resolve the power plant and the coastal geometry with a grid resolution much higher than that used in previous modeling experiments. Therefore, it gives us an opportunity to examine the necessity whether the detailed structure of the Power plant should be considered for numerical experiment of 137Cs dispersion or not. This could provide us an alternative insight into the physical processes that lead to its spread of 137Cs over the shelf of Japan. Our results suggested that to resolve the dispersion process from the source point to the south and north discharging canal is critical for an accurate prediction of the spread of 137Cs to the 30 km sites off the coast. Moreover, a 2 km grid resolution along Japan coast is probably not high enough to resolve the plume correctly. Finally, the model-data comparison suggested that the physical process associated with the transfer of dissolved 137Cs into the sediment phase could potentially be important and should be considered in the future tracer modeling.
The Medieval Climate Anomaly and the Little Ice Age in the eastern Ecuadorian Andes
Authors: Ledru M.-P. , Jomelli V. , Samaniego P. , Vuille M. , Hidalgo S. , Herrera M. , Ceron C.
Published: February 2013

Abstract. To better characterize the climate variability of the last millennium in the high Andes, we analyzed the pollen content of a 1150-yr-old sediment core collected in a bog located at 3800 m a.s.l. in the páramo in the eastern Cordillera in Ecuador. An upslope convective index based on the ratio between cloud transported pollen from the Andean forest to the bog (T) and Poaceae pollen frequencies, related to the edaphic moisture of the páramo (P), was defined. This index was used to distinguish changes in the atmospheric moisture from the soil moisture content of the páramo and their associated patterns of interdecadal El Niño–Southern Oscillation (ENSO) variability and South American summer monsoon (SASM) activity. Results show that between 850 and 1250 AD, the Medieval Climate Anomaly interval was warm and moist with a high transported pollen/Poaceae pollen (T/P) index linked to high ENSO variability and weak SASM activity. Between 1250 and 1550 AD, a dry climate prevailed, characterized by an abrupt decrease in the T/P index and therefore no upslope cloud convection, related to lower ENSO variability and with significant impact on the floristic composition of the páramo. During the Little Ice Age, two phases were observed: first, a wet phase between 1550 and 1750 AD linked to low ENSO variability in the Pacific and warm south equatorial Atlantic sea surface temperatures (SSTs) favored the return of a wet páramo, and then a cold and dry phase between 1750 and 1800 AD associated with low ENSO variability and weak SASM activity resulted in drying of the páramo. The current warm period marks the beginning of a climate characterized by high convective activity – the highest in the last millennium – and weaker SASM activity modifying the water storage of the páramo. Our results show that the páramo is progressively losing its capacity for water storage and that the interdecadal variability of both tropical Pacific and Atlantic SSTs matter for Andean climate patterns, although many teleconnection mechanisms are still poorly understood.
Seemingly divergent sea surface temperature proxy records in the central Mediterranean during the last deglacial
Authors: Sicre M.-A. , Siani G. , Genty D. , Kallel N. , Essallami L.
Published: February 2013

Abstract. Sea surface temperatures (SSTs) were reconstructed over the last 25 000 yr using alkenone paleothermometry and planktonic foraminifera assemblages from two cores of the central Mediterranean Sea: the MD04-2797 core (Siculo–Tunisian channel) and the MD90-917 core (South Adriatic Sea). Comparison of the centennial scale structure of the two temperature signals during the last deglacial period reveals significant differences in timing and amplitude. We suggest seasonal changes likely account for seeming proxy record divergences during abrupt transitions from glacial to interglacial climates and for the apparent short duration of the Younger Dryas (YD) depicted by the alkenone time-series, a feature that has already been stressed in earlier studies on the Mediterranean deglaciation.
An optical model for deriving the spectral particulate backscattering coefficients in clear and turbid coastal waters
Authors: Tiwari S. P. , Shanmugam P.
Published: February 2013

Abstract. An optical model is developed based on the diffuse attenuation coefficient (Kd) to estimate particulate backscattering coefficients bbp(λ) in clear and turbid coastal waters. A large in-situ data set is used to establish robust relationships between bbp(530) and bbp(555) and Kd(490) using an efficient nonlinear least square method which uses the Trust-Region algorithm with Bisquare weights scheme to adjust the coefficients. These relationships are obtained with good correlation coefficients (R2 = 0.786 and 0.790), low Root Mean Square Error (RMSE = 0.00076 and 0.00072) and 95% confidence bounds. The new model is tested with two independent data sets such as the NOMAD SeaWiFS Match-ups and OOXIX IOP algorithm workshop evaluation data set (Version 2.0w APLHA). Results show that the new model makes good retrievals of bbp at all key wavelengths (from 412–683 nm), with statistically significant improvements over other inversion models. Thus, the new model has the potential to improve our knowledge of particulate matters and their optical variability in both clear and turbid coastal waters.
Serum NGAL in Critically Ill Children in ICU from a Single Center in Egypt
Authors: Youssef Doaa Mohammed , Esh Asmaa Mohammed , Helmy Hassan Ebthag , Ahmed Tahia Mohammed
Published: February 2013

Introduction.The mortality and morbidity associated with acute kidney injury (AKI), unfortunately, remain unacceptably high. We aimed to detect the extent of serum neutrophil gelatinase-associated lipocalin (NGAL) to early detect AKI in critically ill children.Subjects and Methods.This is a case control study. It included 75 subjects that include 15 as controls and 60 critically ill children. Patients were further subdivided according to RIFLE criteria into two other categories: patients who developed AKI and patients who did not develop AKI. Serum NGAL assayed on admission and after 3 days.Results.There was significant increase in the level of NGAL among patients group when compared with control group. Also, 21.7% of children admitted to PICU developed AKI from which 8.3% needed dialysis. The receiver operating characteristic curve of NGAL at day 0 revealed AUC of 0.63 with 95% CI of 0.50–0.77. At a cutoff value of 89.5 ng/mL, the sensitivity of NGAL was 84.6%, while specifcity was 59.6%, positive predictive value was 36.7%, negative predictive value was 68.4%, and accuracy was 93.3% in diagnosis of AKI.Conclusion.We found that NGAL acts as a sensitive marker rather than a specific one for AKI. At the same time, it presents as a negative predictive value more valuable than being a positive predictive value in detecting AKI.
Conductance Fluctuations in Chains of Particles Arising from Conformational Changes of Stabilizer Molecules
Authors: Govor L. V. , Parisi J.
Published: February 2013

We have bridged a pair of gold electrodes with various arrangements of gold nanoparticles stabilized with citrate molecules. The resulting devices exhibited current fluctuations at a constant bias voltage and fluctuations of the differential conductance as a function of the bias voltage. These fluctuations were attributed to the interplay of molecular conformation, charge switching, and breaking of the links at the interface molecules-electrode. We found that, for all investigated samples, the contact resistance at the interface molecules-electrode was by about one order of magnitude larger than that between nanoparticles coupled by citrate molecules. We conclude that the mechanism of charge transport can be viewed as a series of discrete steps involving initial hopping (injection) of the charge from the left-hand-side gold electrode to the molecules, tunnelling of the charge through the molecules-nanoparticle-molecules (MNM) unit, hopping to the next MNM unit, etc., and finally hopping (extraction) of the charge to the right-hand-side gold electrode.
Radiative and Porous Effects on Free Convection Flow near a Vertical Plate that Applies Shear Stress to the Fluid
Authors: Fetecau Corina , Rana Mehwish , Fetecau Constantin
Published: February 2013

General solutions for the unsteady free convection flow of an incompressible viscous fluid due to an infinite vertical plate that applies a shear stress f (t) to the fluid are established when thermal radiation and porous effects are taken into consideration. They satisfy all imposed initial and boundary conditions and can generate a large class of exact solutions corresponding to different motions with technical relevance. The velocity is presented as a sum of thermal and mechanical components. Finally, some special cases are brought to light, and effects of pertinent parameters on the fluid motion are graphically underlined.
Molecular Simulations of Hydrated Proton Exchange Membranes: the Structure
Authors: Marchand Gabriel , Bopp Philippe A. , Spohr Eckhard
Published: February 2013

The structure of two hydrated proton exchange membranes for fuel cells (PEMFC), Nafion® (Dupont) and Hyflon® (Solvay), is studied by all-atom molecular dynamics (MD) computer simulations. Since the characteristic times of these systems are long compared to the times for which they can be simulated, several different, but equivalent, initial configurations with a large degree of randomness are generated for different water contents and then equilibrated and simulated in parallel. A more constrained structure, analog to the newest model proposed in the literature based on scattering experiments, is investigated in the same way. One might speculate that a limited degree of entanglement of the polymer chains is a key feature of the structures showing the best agreement with experiment. Nevertheless, the overall conclusion remains that the scattering experiments cannot distinguish between the several, in our view equally plausible, structural models. We thus find that the characteristic features of experimental scattering curves are, after equilibration, fairly well reproduced by all systems prepared with our method. We thus study in more detail some structural details. We attempt to characterize the spatial and size distribution of the water rich domains, which is where the proton diffusion mostly takes place, using several clustering algorithms.
High Enrichment of 6Li in Molten Nitrates by the Klemm Method
Authors: Okada Isao , Nomura Masao , Haibara Teruo
Published: February 2013

The Klemm method of isotopic enrichment (countercurrent electromigration of molten salts) and many of its implications are reviewed and discussed. On the basis of this principle, a small amount of 6Li was enriched in some experiments from its original abundance, 7:6%, to 94:9% at about 300 °C. The variation of the conditions led to a modified setup where, by disposing a small amount of NaNO3 between the catholyte (NH4NO3) and the zone of LiNO3, the frontal part, where 6Li is to be enriched, could be kept stable under high current density for more than one month without any problem of corrosion. The reasons and implications of this new step are discussed, underlining the up-to-dateness of Klemm’s experiment.
From "Bio-Power" to "Neuropolitics"
Authors: Sardamov Ivelin ,   Philosophy Documentation Center
Published: February 2013

According to Foucault, power in modern society is diffuse and pervasive, and works through the agency of free subjects. Its imperatives are internalized by indi­viduals who become self-disciplined, are tied to a particular identity, and govern their own behavior accordingly. Drawing on recent insights from neuroscience, the whole process of norm internalization can be seen as an expression of “neuropower” and a form of “neuropolitics” through which social and power relations become ingrained not just in human bodies and minds, but also in human brains. In recent decades, this process has been partly reversed as a result of the proliferation of information technologies and the electronic media.
Revision of Dadagulella gen. nov., the “Gulella radius group" (Gastropoda: Streptaxidae) of the eastern Afrotropics, including six new species and three new subspecies
Authors: Rowson Ben , Tattersfield Peter
Published: February 2013

The genus Dadagulella gen. nov. is described to include 16 species of small, dentate, ovate-acuminate Afrotropical snails. An identification key is provided and biogeography, anatomy and systematics are discussed. The type species is the Kenyan D. radius (Preston, 1910) comb. nov., whose name has informally been used for part of the group in the past. Substantial intraspecific variation occurs in three species: D. radius itself, D. browni (van Bruggen, 1969) comb. nov. and D. minuscula (Morelet, 1877) comb. nov. (= Ennea fischeriana Morelet, 1881) (non Gulella minuscula Emberton & Pearce, 2000) . We recognise subspecies within each of these: D.radius radius (Preston, 1910) comb. nov., D. r. calva (Connolly, 1922) comb. et stat. nov., D. browni browni (van Bruggen, 1969) comb. nov., D. b. mafiensis subsp. nov., D. b. semulikiensis subsp. nov., D. minuscula minuscula (Morelet, 1877) comb. nov., D. m. mahorana subsp. nov. Six new Tanzanian species are described: D. cresswelli sp. nov., D. delta sp. nov., D. ecclesiola sp. nov., D. frontierarum sp. nov., D. minareta sp. nov., and D. pembensis sp. nov. The genus includes seven other previously described species: D. cuspidata (Verdcourt, 1962) comb. nov.; D. rondoensis (Verdcourt, 1994) comb. nov.; D. conoidea (Verdcourt, 1996) comb. nov.; D. selene (van Bruggen & Van Goethem, 1999) comb. nov.; D. meredithae (van Bruggen, 2000) comb. nov.; D. nictitans (Rowson & Lange, 2007) comb. nov.; and D. delgada (Muratov, 2010) comb. nov.
Model Eliciting Activities: A Home Run
Authors: Magiera Marta T.
Published: February 2013

An aluminum bat activity supports goals of STEM learning by engaging students in resourceful problem solving.
Coordinate an Attack Using the Calculator
Authors: Kranz Sharie R. , Amato Carlo A. , Freudenthal Eric A.
Published: February 2013

Teachers using these graphing tasks experienced engagement in understanding the need for the coordinate system.
A Pathway for Mathematical Practices
Authors: Wenrick Melanie , Behrend Jean L. , Mohs Laura C.
Published: February 2013

See how the NCTM Process Standards in action integrate Common Core State Standards in a second-grade classroom.
Fundamental Problems of Internal Gravity Waves Dynamics in Ocean
Authors: Vitaly V. Bulatov  , Yury V. Vladimirov
Published: February 2013

In paper fundamental problems of internal gravity waves dynamics are considered. The solution of this problem is expressed in terms of the Green’s function and the asymptotic representations of the solutions are considered. The uniform asymptotic forms of the internal gravity waves in horizontally inhomogeneous and non-stationary stratified ocean are obtained. A modified spatio-temporal ray method is proposed, which belongs to the class of geometrical optics methods (WKBJ method). Analytical and numerical algorithms of internal gravity wave calculations for the real ocean parameters are presented.
Revisiting Walter Benjamin’s “The Task of the Translator” in Light of His Concept of Criticism in German Romanticism1
Authors: St. André James
Published: February 2013

Walter Benjamin’s essay “The Task of the Translator,” the most widely cited twentieth century philosophical statement on translation, is commonly seen as one of the most opaque and misunderstood essays in the field. This paper uses a close reading of Benjamin’s doctoral thesis, “The Concept of Criticism in German Romanticism,” to throw light on his thoughts on translation. I argue that the German Romantics’ definition of art, and art’s relation to criticism, are crucial to understanding why Benjamin conceived of translation as an “afterlife” of the work of art, why he believed that translatability is an innate quality of the work of art, and why he speaks of translation as moving the work of art onto a higher plane. I read Benjamin’s own essay on translation as a sort of “criticism” which seeks to “translate” the philosophical ideals of the Romantics, and thus give them an afterlife, and then reflect upon the implications for translation studies today.
Utiliser des médicaments stimulants pour améliorer sa performance : usages et discours de jeunes adultes québécois
Authors: Thoër Christine , Robitaille Michèle
Published: February 2013

L’utilisation de médicaments stimulants par les étudiants pour améliorer la performance académique en l’absence de trouble de déficit de l’attention avec hyperactivité (TDAH) et hors du cadre de la prescription, est une pratique qui semble gagner en popularité auprès des étudiants américains. Cette recherche exploratoire basée sur des entrevues semi-dirigées réalisées auprès de 26 jeunes adultes québécois étudiants et travailleurs, âgés de 20 à 25 ans, visait à documenter l’usage de stimulants et à cerner les significations qu’ils construisent autour de ces utilisations. Nos résultats montrent qu’étudiants et travailleurs recourent aux stimulants pour augmenter leur concentration et leur capacité à rester alertes dans le but d’améliorer la qualité de leur travail et leur productivité. Les discours que construisent ces jeunes adultes autour de ces pratiques renvoient à trois problématiques : une faille personnelle, un déséquilibre perçu entre les ressources personnelles et les contraintes qu’impose l’environnement académique ou professionnel et une difficulté à concilier les engagements dans des rôles multiples. Le recours aux médicaments stimulants est ainsi présenté par les jeunes adultes comme une stratégie d’automédication ou comme une ressource pour favoriser l’adaptation aux exigences de l’environnement ou aux multiples engagements identitaires. Les médicaments stimulants sont perçus comme des produits efficaces et relativement sécuritaires, et leur utilisation pour améliorer la performance est jugée légitime puisqu’elle vise la réussite académique ou professionnelle.
Time line of redox events in aging postmitotic cells
Authors: Brandes Nicolas , Tienson Heather , Lindemann Antje , Vitvitsky Victor , Reichmann Dana , Banerjee Ruma , Jakob Ursula
Published: February 2013

The precise roles that oxidants play in lifespan and aging are still unknown. Here, we report the discovery that chronologically aging yeast cells undergo a sudden redox collapse, which affects over 80% of identified thiol-containing proteins. We present evidence that this redox collapse is not triggered by an increase in endogenous oxidants as would have been postulated by the free radical theory of aging. Instead it appears to be instigated by a substantial drop in cellular NADPH, which normally provides the electron source for maintaining cellular redox homeostasis. This decrease in NADPH levels occurs very early during lifespan and sets into motion a cascade that is predicted to down-regulate most cellular processes. Caloric restriction, a near-universal lifespan extending measure, increases NADPH levels and delays each facet of the cascade. Our studies reveal a time line of events leading up to the system-wide oxidation of the proteome days before cell death.
Hierarchical organization of context in the hippocampal episodic code
Authors: Takahashi Susumu
Published: February 2013

The hippocampal system appears to be critically important in establishing episodic memory of both internal and external events within contexts as well as spatial memory, which enables flexible spatial navigation. However, the neuronal substrates that function across different memories in the hippocampal system are poorly understood. I monitored large-scale activity patterns of hippocampal neuronal ensembles in rats performing a novel, continuous task that combined one visually guided and two memory-guided types of navigations in a constant environment. I found that the activity patterns of the hippocampal ensemble represent spatiotemporal contexts (journeys) constructed by temporally ordered past, present and expected future places in tandem with visually or mnemonically guided non-spatial contexts (task-demands) to form episodes. This finding therefore suggests that the hierarchical organization of contexts based on pattern separation and completion enables the hippocampus to play a dual role in spatial navigation and recall of episodic memory.
Recognition of familiar food activates feeding via an endocrine serotonin signal in Caenorhabditis elegans
Authors: Song Bo-mi , Faumont Serge , Lockery Shawn , Avery Leon
Published: February 2013

Familiarity discrimination has a significant impact on the pattern of food intake across species. However, the mechanism by which the recognition memory controls feeding is unclear. Here, we show that the nematode Caenorhabditis elegans forms a memory of particular foods after experience and displays behavioral plasticity, increasing the feeding response when they subsequently recognize the familiar food. We found that recognition of familiar food activates the pair of ADF chemosensory neurons, which subsequently increase serotonin release. The released serotonin activates the feeding response mainly by acting humorally and directly activates SER-7, a type 7 serotonin receptor, in MC motor neurons in the feeding organ. Our data suggest that worms sense the taste and/or smell of novel bacteria, which overrides the stimulatory effect of familiar bacteria on feeding by suppressing the activity of ADF or its upstream neurons. Our study provides insight into the mechanism by which familiarity discrimination alters behavior.
Current Enhancement with Contact-Area-Limited Doping for Bottom-Gate, Bottom-Contact Organic Thin-Film Transistors
Authors: Noda Kei , Wakatsuki Yusuke , Yamagishi Yuji , Wada Yasuo , Toyabe Toru , Matsushige Kazumi
Published: February 2013

The current enhancement mechanism in contact-area-limited doping for bottom-gate, bottom-contact (BGBC) p-channel organic thin-film transistors (OTFTs) was investigated both by simulation and experiment. Simulation results suggest that carrier shortage and large potential drop occur in the source-electrode/channel interface region in a conventional BGBC OTFT during operation, which results in a decrease in the effective field-effect mobility. These phenomena are attributed to the low carrier concentration of active semiconductor layers in OTFTs and can be alleviated by contact-area-limited doping, where highly doped layers are prepared over source–drain electrodes. According to two-dimensional current distribution obtained from the device simulation, a current flow from the source electrode to the channel region via highly doped layers is generated in addition to the direct carrier injection from the source electrode to the channel, leading to the enhancement of the drain current and effective field-effect mobility. The expected current enhancement mechanism in contact-area-limited doping was experimentally confirmed in typical α-sexithiophene (α-6T) BGBC thin-film transistors.
Spectral and Transient Luminescence Measurements on GaSb/AlGaSb Quantum Wells Grown on GaSb/GaAs Heterojunctions with and without Interfacial Misfit Arrays
Authors: Jahan Nahid A. , Ahirwar Pankaj , Rotter Thomas J. , Balakrishnan Ganesh , Kumano Hidekazu , Suemune Ikuo
Published: February 2013

Growth of 90° interfacial-misfit-dislocation (IMF) array at heterointerfaces offers low dislocation densities in highly mismatched heterostructures such as GaSb/GaAs. We investigated time-integrated and time-resolved photoluminescence (PL) properties of a GaSb/AlGaSb quantum well (QW) structure grown on (001) GaAs substrate with and without IMF array at the GaSb-buffer/GaAs interface. Our observation reveals that the low-temperature PL from the QW with IMF is twice more intense than that of the QW without IMF, indicating higher quantum efficiency with IMF. The QW with IMF also exhibited the band filling effect at higher excitation power revealed from the spectrally resolved PL decay measurements. These results are the indication of subdued dislocation density with the IMF growth mode. Our PL measurement results along with supportive band-structure calculation of the GaSb/AlGaSb QW show that the luminescence efficiency of the present QW structure is limited by the hole leakage at elevated temperature. Therefore the IMF effect will be more clearly demonstrated by replacing the heterostructure with the one with higher band-offsets.
Analytical Model for Direct Tunneling Gate Current in Long-Channel Undoped Cylindrical Surrounding Gate Metal–Oxide–Semiconductor Field Effect Transistors
Authors: Han Ru , Li Cong
Published: February 2013

In this study, an analytical direct tunneling gate current model for long-channel undoped cylindrical surrounding gate (CSG) MOSFETs is developed. On the basis of an analytical model, the direct tunneling gate current in CSG MOSFETs is investigated. It is found that direct tunneling gate current is a strong function of gate oxide thickness, but less affected by the change in channel radius. It is also revealed that considering the influence of the source and drain, as the length of the underlap region decreases to zero, the direct tunneling gate current drastically increases. The accuracy of the analytical model is verified by the good agreement of its results with those obtained by the three-dimensional numerical device simulator ISE.
Device Quality Evaluation of Periodically Poled Crystals by Diffraction Analysis at Different Wavelengths
Authors: Choi Ju Won , Kang Heejong , Ko Do-Kyeong , Ro Jung Hoon , Yu Nan Ei
Published: February 2013

A quality evaluation method of periodically poled crystals was suggested using two different wavelengths based on an analysis of far-field diffraction. To confirm the ability of our tool, diffraction intensities were obtained at various samples, and experimental results agreed well with simulation curve based on the binary phase grating theory. The proposed tool could easily distinguish that efficiency variation of second harmonic within an error of less than 2.54%. It could be a highly precise and convenient method to investigate periodically poled structures.
High-Breakdown-Voltage and Low-Specific-on-Resistance GaN p–n Junction Diodes on Free-Standing GaN Substrates Fabricated Through Low-Damage Field-Plate Process
Authors: Hatakeyama Yoshitomo , Nomoto Kazuki , Terano Akihisa , Kaneda Naoki , Tsuchiya Tadayoshi , Mishima Tomoyoshi , Nakamura Tohru
Published: February 2013

In this letter, we describe the characteristics of Gallium Nitride (GaN) p–n junction diodes fabricated on free-standing GaN substrates with low specific on-resistance R
on and high breakdown voltage V
B. The breakdown voltage of the diodes with the field-plate (FP) structure was over 3 kV, and the leakage current was low, i.e., in the range of 10-4 A/cm2. The specific on-resistance of the diodes of 60 µm diameter with the FP structure was 0.9 mΩ·cm2. Baliga's figure of merit (V
B
2/R
on) of 10 GW/cm2 is obtained. Although a certain number of dislocations were included in the device, these excellent results indicated a definite availability of this material system for power-device applications.
Synthesis and Characterization of Novel Smart Flocculant Based on Poly(MAam)‐Pregelled Starch Graft Copolymers and Their Degraded Products
Authors: Mostafa Kh. M. , El‐Sanabary A. A.
Published: February 2013

Poly(methacrylamide)‐pregelled starch graft copolymers derived from native pregelled starch (substrate I) and hydrolyzed pregelled starches having different molecular weights were prepared and evaluated as flocculants for ferric laurate aqueous dispersions. This was done by subjecting substrate I as a starting substrate to acid hydrolysis to obtain three levels of hydrolyzed pregelled starch having different molecular weights (substrates II–IV). The latter were graft copolymerized with various amounts of methacrylamide monomers using an Mn(IV)‐citric acid redox pair for initiating grafting to obtain copolymers having different graft yields. The flocculation efficiency was followed by estimating the transmission (%) and weight removal (%) of the flocculants. The grafted pregelled starches were characterized by estimating apparent viscosity, intrinsic viscosity, and elemental analysis. The major factors affecting the flocculation process such as the flocculent dose, pH of the flocculation medium, and molecular weight as well as the extent of grafting were studied in detail. It is observed from the obtained results that the flocculation efficiency of the prepared copolymers (a) increases by increasing the flocculants dose to reach a peak value then decreases thereafter; (b) increases by decreasing the pH values from 8 to 6; (c) increases by decreasing the molecular weight of the parent starch and follows the following order: substrate IV < substrate III < substrate II < substrate I; (d) increases by increasing the extent of grafting within the range studied; and (e) poly(methacrylamide)‐graft copolymers derived from hydrolyzed pregelled starch (substrates II–IV) show a higher flocculation efficiency than polyacrylamide as a synthetic flocculant. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21339; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21339
Quinolinesulfonamides of Aryloxy‐/Arylthio‐ethyl Piperidines: Influence of an Arylether Fragment on 5‐HT1A/5‐HT7 Receptor Selectivity
Authors: Grychowska Katarzyna , Marciniec Krzysztof , Canale Vittorio , Szymiec Michał , Glanowski Grzegorz , Satała Grzegorz , Maślankiewicz Andrzej , Pawłowski Maciej , Bojarski Andrzej J. , Zajdel Paweł
Published: February 2013

The solid‐phase synthesis of a new series of 19 biomimetics of long‐chain arylpiperazines, namely flexible quinoline sulfonamides of aryl(heteroaryl)oxy‐/heteroarylthio‐ethyl 4‐aminomethylpiperidines, is reported. Various structural modifications applied followed by biological evaluation for 5‐HT1A, 5‐HT6, and 5‐HT7 receptors gave further support of a possible replacement of arylpiperazine with aryloxy‐/arylthio‐ethyl derivatives of alicyclic amines and control of receptor selectivity upon diversification in the aryl(heteroaryl)oxy‐/heteroarylthio‐ethyl fragment.
Alternating Direction Implicit‐Methoden für die Bauteilsimulation: Chancen und Herausforderungen
Authors: Paepcke Anne , Nicolai Andreas
Published: February 2013

Die Simulation komplexer baukonstruktiver Details stellt hohe Anforderungen an numerische Lösungsverfahren. In dem Artikel wird sich auf das Alternating Direction Implicit (ADI)‐Verfahren als Alternative zum klassischen Impliziten Euler‐Verfahren konzentriert. Neben der direkten Anwendung wird eine Block‐Variante eingeführt und mit zwei verschiedenen Lösungsstrategien kombiniert: als ADI‐Zeitschrittverfahren und als ADI‐Vorkonditionierer für ein Krylov‐Unterraum‐Verfahren innerhalb einer impliziten Euler‐Zeitschrittintegration. Die numerischen Verfahren werden an zwei repräsentativen Beispielen getestet: der Trocknungsprozess einer Ziegelwand und ein Wärmebrückenproblem. Die Ergebnisse geben Aufschluss über die Anwendbarkeit der numerischen Methoden auf hochgradig nichtlineare Problemstellungen unter dem Einfluss unstetiger Materialeigenschaften.

Chances and challenges of using Alternating Direction Implicit (ADI) methods for heat and moisture transport simulation. The simulation of complex details of building constructions imposes high demands on the numerical solution method. The article focuses on the Alternating Direction Implicit (ADI) method. We introduce the direct solution technique and a block variant of this method and combine it with different numerical strategies: an ADI time stepping procedure and an ADI preconditioned Krylov subspace method combined with an implicit Euler time integration. In order to check capability of the different numerical methods we design two representative examples: the drying of a brick wall and a thermal bridge simulation. The results give an indication about the applicability of the numerical methods to highly nonlinear problems combined with discontinuous material properties.
Energieeffiziente Kühlung und thermischer Raumkomfort (Teil 2): Simulationsbasierte Evaluierung von Kühlkonzepten in verschiedenen europäischen Klimazonen
Authors: Pfafferott Jens , Kalz Doreen
Published: February 2013

Unter dem europäischen Programm Intelligent Energy for Europe (IEE) fanden sich acht europäische Partner zusammen, um im Rahmen des Projektes ThermCo Lüftungs‐ und Kühlenergiekonzepte für Nichtwohngebäude mit niedrigem Energieeinsatz im Hinblick auf die Energieeffizienz und den thermischen Raumkomfort zu bewerten (siehe Teil 1 dieser Veröffentlichung in Bauphysik 34 (2012), Heft 6. Mit Hilfe einer Simulationsstudie für ein typisches Bürogebäude wird das Potenzial unterschiedlicher Lüftungs‐ und Kühlstrategien unter Berücksichtigung von Energieeffizienz und Raumkomfort für verschiedene europäische Klimazonen bewertet. Die Ergebnisse weisen eine hohe Wirksamkeit von Nachtlüftungskonzepten im nord‐europäischen Sommerklima mit verhältnismäßig niedrigen Außentemperaturen nach. Im mitteleuropäischen Sommerklima bietet das Erdreich ein ausreichend niedriges Temperaturniveau für den effizienten Einsatz von wassergeführten Flächentemperiersystemen. Im südeuropäischen Sommerklima kann eine aktive Kühlung über Luft die hohen und schnell fluktuierenden Kühllasten effizient abführen.

Energy efficient cooling and ventilation concepts for thermal interior comfort: Simulation‐based evaluation of cooling concepts in different European climate zones (Part 2). Under the framework of the European Program Intelligent Energy for Europe (IEE), the project ThermCo evaluates low‐energy ventilation and cooling concepts for non‐residential buildings all‐over Europe using a standardized method based on existing monitoring data from best practice examples (part 1, in Bauphysik 6/2012). A simulation study investigates the potential of different ventilation and cooling strategies with regard to energy efficiency and thermal comfort in different European climates. The results demonstrate a high potential for night ventilation strategies in North‐European climate with low ambient air temperatures. In the Mid‐European climate, water based low‐energy cooling technologies based on radiant cooling make use of the cool ground in summer. Active cooling provides good thermal comfort in South‐European climate with high and fluctuating cooling loads.
Grünbrücken als Verbundkonstruktion
Authors: Suffner Andrea , Ommert Christian , Schiller Guido
Published: February 2013

Für die Bauaufgabe Grünbrücke sind verschiedene Bauwerkskonstruktionen bekannt und in der Vergangenheit ausgeführt worden. Unter den besonderen Bedingungen einer ebenen Topografie und der Errichtung der Bauwerke unter Aufrechterhaltung des Verkehrs über bestehenden Autobahnen mit hoher Verkehrsbelastung wird eine mittelstützenfreie Verbundkonstruktion beschrieben sowie auf die Besonderheiten in Planung und Herstellung eingegangen.

Im Land Brandenburg wurden in den letzten drei Jahren drei dieser Grünbrücken gleicher Bauart mit Verbundfertigteilen errichtet.

Green bridges as composite structures

Several types of structures are known to build green bridges and have been implemented in the past. Under the particular conditions of an even topography – even or flat terrain – and of construction whilst maintaining traffic above existing highly frequented motorways, a composite structure without central supports is described and the particularities of its design and construction are explained.

In the State of Brandenburg, in the last three years, three of these green bridges of the same construction type were erected with prefabricated composite elements.
Experimentelle Untersuchungen zur mitwirkenden Breite für Querkraft von einfeldrigen Fahrbahnplatten
Authors: Reißen Karin , Hegger Josef
Published: February 2013

Die Anforderungen an Brückenbauwerke haben sich in den vergangenen Jahren infolge der steigenden Verkehrszahlen deutlich erhöht. Gleichzeitig hat sich mit der Umstellung der Normen der rechnerische Querkraftwiderstand von Bauteilen ohne Querkraftbewehrung verringert. Als Folge lässt sich für Brückenbauwerke im Bestand mit Fahrbahnplatten ohne Querkraftbewehrung nach derzeitigen technischen Regeln oft keine ausreichende Querkrafttragfähigkeit nachweisen. Daher wurde im Rahmen eines von der Bundesanstalt für Straßenwesen (BASt) geförderten Forschungsvorhabens das Querkrafttragverhalten von Fahrbahnplatten aus Stahlbeton genauer analysiert. Der vorliegende Aufsatz beschreibt die Ergebnisse der experimentellen Untersuchungen zur maßgebenden Lastverteilungsbreite für Radlasten bei einfeldrigen, gelenkig gelagerten Platten ohne Querkraftbewehrung.

Experimental investigations on the effective width for shear of single span bridge deck slabs

The requirements for the load‐carrying capacity of bridges have increased significantly due to rising traffic loads in the last decades. Furthermore, the design rules of the German codes have changed leading to smaller calculated shear capacities of reinforced concrete members without shear reinforcement. Therefore, the calculated shear capacity of a large number of existing concrete bridge deck slabs without shear reinforcement is not sufficient. For the above reasons, the shear‐bearing behaviour of slabs has been investigated within a research programme funded by the Federal Highway Research Institute of Germany (BASt). The paper presents the results of the experimental investigations on the effective width for shear of simply supported single span slabs without shear reinforcement.
Beurteilung der Wirkungsweise von adaptiven Seildämpfern im Brückenbau durch Koppelung von numerischer Simulation und Experiment
Authors: Scheufler Wolfgang , Burghard Stefan , Fischer Oliver , Braun Christian
Published: February 2013

In vielen weit gespannten Schrägseilbrücken werden Seildämpfer zur Verringerung von Seilschwingungen eingebaut. Bedämpft werden dabei in erster Linie unerwünschte Querschwingungen (Schwingungen außerhalb der Kabelebene) der Tragseile. Neben der vorgesehenen Reduzierung der Bewegungen in der Kabelebene der Wirkungsrichtung der Dämpfer zeigen Untersuchungen, dass auch die Bewegungen quer zu dieser Richtung von den Dämpfern beeinflusst werden. Mithilfe der hybriden Versuchstechnik sollen diese Phänomene im Rahmen eines Forschungsvorhabens am Lehrstuhl für Massivbau der Technischen Universität München genauer untersucht werden.

Evaluation of the effects of adaptive cable dampers by use of hybrid testing methods

Various wide spanned cable‐stayed bridges are protected against cable vibrations with vibration absorbers. The focus of the damping measures is to reduce lateral oscillations of the cables. Although reducing vibrations in the effective direction of the installed vibration absorber, it is approved by research that vibrations are influenced transverse to the vibration absorber's effective direction as well. Using hybrid testing methods these phenomenons shall be discovered in detail within an actual research project at the Department of Concrete Structures of the Technische Universität München.
Binary classification with pFDR‐pFNR losses
Authors: Dickhaus Thorsten , Blankertz Benjamin , Meinecke Frank C.
Published: February 2013

Connecting multiple testing with binary classification, we derive a false discovery rate‐based classification approach for two‐class mixture models, where the available data (represented as feature vectors) for each individual comparison take values in for some and may exhibit certain forms of autocorrelation. This generalizes previous findings for the independent case in dimension . Two resulting classification procedures are described which allow for incorporating prior knowledge about class probabilities and for user‐supplied weighting of the severity of misclassifying a member of the “0”‐class as “1” and vice versa. The key mathematical tools to be employed are multivariate estimation methods for probability density functions or density ratios. We compare the two algorithms with respect to their theoretical properties and with respect to their performance in practice. Computer simulations indicate that they can both successfully be applied to autocorrelated time series data with moving average structure. Our approach was inspired and its practicability will be demonstrated by applications from the field of brain‐computer interfacing and the processing of electroencephalography data.