bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of 9,10‐diphenylanthracene‐based blue light emitting materials
Authors: Kim Sul Ong , Jung Hyun Cheol , Lee Min‐Jung , Jun Chen , Kim Yun‐Hi , Kwon Soon‐Ki
Published: September 2009

A new series of conjugated polymers having diphenylanthracene vinylene biphenylene and diphenylanthracene vinylene terphenylene in the main chain and fluorene pendant group, were synthesized by nickel catalized Yamamoto coupling and palladium catalized Suzuki coupling. The obtained polymers showed good solubility in the common organic solvent and number average molecular weights of 14,000–9500 with a polydispersity indexes ranging from 1.7 to 2.1. Both polymers possess excellent thermal stability with glass transition temperatures of 123–127 °C and the onset decomposition temperatures of 420–400 °C. The obtained polymers showed blue emission (λmax = 461 for PFPA and λmax = 455 nm for PFPAME) in PL spectra, specially, PFPAME containing diphenylanthracene vinylene terphenylenevinylene showed the consistent emission in the solution and film. The double‐layered device with an ITO/PEDOT/PFPAME/LiF/Al structure has a turn‐on voltage of about 5.8 V, maximum brightness of 152 cd/m2 and an electroluminescent efficiency of 0.143 lm/W, and stable blue EL emission that is not altered by increased voltage. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5908–5916, 2009
The current global status of chinese materia medica
Authors: Xinmin Liu , Jiangqiang Zou , Zhixiang Sheng , Guangqiang Su , Shilin Chen
Published: September 2009

The Chinese government has recently established a national project to improve the standards of Chinese Materia Medica (CMM) products, particularly regarding their quality control and safety evaluation, in order to promote modernization and increase international trade. In 2006, the global sales value of Chinese medicinal products increased to 20 billion US$, and the export value of CMM was up to more than 1 billion US$. However, the standard of these products still needs to be improved to meet the more stringent requirements of the international markets. Over the past decade we have witnessed the increasing growth in popularity of health foods and herbal medicinal products, especially Chinese Materia Medica products (CMM). Copyright © 2009 John Wiley & Sons, Ltd.
Evolution of the stable water isotopic composition of the rain sampled along Sahelian squall lines
Authors: Risi Camille , Bony Sandrine , Vimeux Francoise , Chong Michel , Descroix Luc
Published: September 2009

In the Tropics, the stable isotopic composition (HDO, H$_{2}^{18}$O) of precipitation is strongly modulated by convective activity. To better understand how convective processes impact the precipitation isotopic composition, we analyze the isotopic composition of rain collected during the passage of four squall lines over the Sahel (Niamey, Niger) in August 2006 during the African Monsoon Multidisciplinary Analysis (AMMA) campaign. The high‐frequency sampling (5−10 min) of the precipitation allows us to investigate the evolution of the precipitation isotopic composition in different phases of the squall lines. Despite a large variability among the different squall lines, some robust isotopic features appear: the W shape of the δ18O evolution and the deuterium excess decrease in the first part of the stratiform zone. To understand more quantitatively how convective processes impact the precipitation isotopic composition, a simple stationary two‐dimensional transport model including a representation of cloud microphysics and isotopic fractionation is developed and forced by three‐dimensional winds retrieved from the Massachusetts Institute of Technology (MIT) radar on 11 August 2006. The model reproduces the robust observed features and a large sensitivity to the squall‐line dynamics. This model suggests that the main controlling factors of the isotopic evolution are (1) squall‐line dynamics, especially the downward advection of air at the rear of the squall lines, affecting the vapour composition and, by isotopic equilibration, the subsequent precipitation composition and (2) rain re‐evaporation. This suggests that water isotopes have the potential to better constrain squall‐line dynamics and rain re‐evaporation, and to evaluate the representation of convective processes in numerical models. Copyright © 2009 Royal Meteorological Society
Estimation of Aqueous‐Phase Reaction Rate Constants of Hydroxyl Radical with Phenols, Alkanes and Alcohols
Authors: Wang Ya‐nan , Chen Jingwen , Li Xuehua , Zhang Siyu , Qiao Xianliang
Published: September 2009

A quantitative structure activity relationship (QSAR) model was developed for the aqueous‐phase hydroxyl radical reaction rate constants (kOH) employing quantum chemical descriptors and multiple linear regressions (MLR). The QSAR development followed the OECD guidelines, with special attention to validation, applicability domain (AD) and mechanistic interpretation. The established model yielded satisfactory performance: the correlation coefficient square (R2) was 0.905, the root mean squared error (RMSE) was 0.139, the leave‐many‐out cross‐validated QLMO2 was 0.806, and the external validated QEXT2 was 0.922 log units. The AD of the model covering compounds of phenols, alkanes and alcohols, was analyzed by Williams plot. The main molecular structural factors governing kOH are the energy of the highest occupied molecular orbital (EHOMO), average net atomic charges on hydrogen atoms ($\rm{ \overline {Q_{\rm{H}}^{} } }$), molecular surface area (MSA) and dipole moment (μ). It was concluded that kOH increased with increasing EHOMO and MSA, while decreased with increasing $\rm{ \overline {Q_{\rm{H}}^{} } }$ and μ.
Resistive Switching in Nanogap Systems on SiO2 Substrates
Authors: Yao Jun , Zhong Lin , Zhang Zengxing , He Tao , Jin Zhong , Wheeler Patrick J. , Natelson Douglas , Tour James M.
Published: September 2009

Voltage‐controlled resistive switching in various gap systems on SiO2 substrates is reported. The nanoscale‐sized gaps are made by several means using different materials including metals, semiconductors, and amorphous carbon. The switching site is further reduced in size by using multiwalled carbon nanotubes and single‐walled carbon nanotubes. The switching in all the gap systems shares the same characteristics. This independence of switching on the material compositions of the electrodes, accompanied by observable damage to the SiO2 substrate at the gap region, bespeaks the intrinsic switching from post‐breakdown SiO2. It calls for caution when studying resistive switching in nanosystems on oxide substrates, since oxide breakdown extrinsic to the nanosystem can mimic resistive switching. Meanwhile, the high ON/OFF ratio (≈105), fast switching time (2 µs, tested limit), and durable cycles show promising memory properties. The observed intermediate states reveal the filamentary nature of the switching.
Grand tour and the Andrews plot
Authors: Moustafa Rida E. , Hadi Ali S.
Published: September 2009

The relationship between Andrews plot and Grand Tour (GT) stems from the fact that both view multiprojections of hyperdimensional data. The difference, however, is that GT views all possible projections of the data, while Andrews plot views only sets of projections. In this paper, we give a quick introduction to GT and Andrews plot and some visualization examples. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Statistical Graphics and Visualization
Role of triggering receptor expressed on myeloid cells‐1 in experimental severe acute pancreatitis
Authors: Kamei Keiko , Yasuda Takeo , Ueda Takashi , Qiang Fu , Takeyama Yoshifumi , Shiozaki Hitoshi
Published: September 2009

Background/purpose

Triggering receptor expressed on myeloid cells‐1 (TREM‐1) is a regulator of immunity and an amplifier of inflammatory signaling. The aim was to clarify the role of TREM‐1 in the pathophysiology of experimental severe acute pancreatitis (SAP).

Methods

SAP was induced by retrograde injection of 3 and 20% sodium deoxycholate (DCA) into the biliopancreatic ducts in rats (DCA pancreatitis). Soluble TREM‐1 levels in serum, ascitic fluid, pancreas, liver and kidney were determined with an established available enzyme‐linked immunosorbent assay (ELISA) kit. To clarify the source of soluble TREM‐1 in serum and ascitic fluid, peritoneal macrophage depletion was done. Moreover, the effect of blockade of TREM‐1 pathway was examined using LP17 (a synthetic TREM‐1 inhibitor).

Results

Soluble TREM‐1 levels in serum and ascitic fluid were higher in SAP. Membrane‐bound TREM‐1 protein was increased in pancreas, liver and kidney in SAP. Peritoneal macrophage depletion resulted in the reduction of soluble TREM‐1 levels in serum and ascitic fluid. Pretreatment with LP17 improved the hepatic and renal dysfunction (serum aspartate aminotransferase and blood urea nitrogen levels) in SAP.

Conclusions

TREM‐1 may act as an important mediator for inflammation and organ injury in SAP. TREM‐1 may be a potential therapeutic target for the development of SAP and associated organ dysfunction.
Rare site giant cell tumors: report of two cases on phalanges of the finger and review of literature
Authors: Saikia Kabul C. , Bhuyan S. K. , Goswami S. , Bora A.
Published: September 2009

Giant cell tumor (GCT) of bone arising from a phalanx of a finger is extremely rare. We report two cases of GCT arising from a phalanx of a finger. One case presented with recurrence following the amputation of the left ring finger (performed elsewhere). He was treated successfully with ray amputation. The other case was treated primarily by intralesional curettage and autogenous bone graft. At their most recent follow-ups (80 and 24 months, respectively), both were recurrence free and had returned to their previous occupational and recreational activities.
A controlled study of consumption of β-glucan-enriched soups for 2 months by type 2 diabetic free-living subjects
Authors: Cugnet-Anceau Christine , Nazare Julie-Anne , Biorklund Maria , Le Coquil Elodie , Sassolas Agnès , Sothier Monique , Holm Jorgen , Landin-Olsson Mona , Önning Gunilla , Laville Martine , Moulin Philippe
Published: September 2009

Type 2 diabetes is associated with a higher cardiovascular risk and there has been a growing interest in using dietary intervention to improve lipid profile and glucose control. The present work aims at analysing the effects of the enrichment of a normal diet with β-glucan (3·5 g/d) in free-living type 2 diabetic subjects for 2 months, using a palatable soup. This trial was a parallel, placebo-controlled, double-blinded randomised study performed in fifty-three type 2 diabetic subjects. During a 3-week run-in period, subjects daily consumed a ready meal control soup (without β-glucan). For the following 8 weeks, subjects were randomly assigned to consume daily either a control soup or a β-glucan soup. Changes in lipid profile (total cholesterol (TC), HDL- and LDL-cholesterol (HDLc and LDLc), apo B and TAG) and in glucose control (HbA1c and fasting glucose) were measured. There was no significant alteration in lipid profile in the two groups (TC, HDLc, LDLc and apo B). TAG decreased significantly in the β-glucan group compared with the control group ( − 0·12 (sd0·38)v. 0·12 (sd0·44) mmol/l,P = 0·03). HbA1c and fasting glucose were not reduced in any group. A single daily ingestion of 3·5 g β-glucan, as required by official dietary recommendations, for 8 weeks did not change the lipid profile and HbA1c in type 2 diabetic subjects. To improve the metabolic profile of type 2 diabetic subjects in the long term, the quantity, the food vectors and the tolerability of β-glucan products may be re-evaluated.
Effects ofBacillus thuringiensisCry1Ab and Cry3Aa endotoxins on predatory Coleoptera tested through artificial diet-incorporation bioassays
Authors: Porcar M. , García-Robles I. , Domínguez-Escribà L. , Latorre A.
Published: September 2009

Traditional approaches to studying the effects of genetically modified (GM) crops on beneficial insects involve either field assays, comparing insect population levels between control and GM crops or tritrophic bioassays with contaminated insects – usually larvae or eggs of Lepidoptera – as preys. Here, we report the results of a bioassay using an artificial diet, suitable for predatory Coleoptera, to supplyBacillus thuringiensis(Bt) solubilized Cry1Ab and Cry3Aa as well as trypsin-activated Cry1Ab toAtheta coriariaandCryptolaemus montrouzieriadults and young larvae ofAdalia bipunctata. Water, solubilization buffer and trypsin-treated solubilization buffer were used as controls. In total, 1600 insects were assayed. Assays showed a relatively low mortality rate in the controls, ranging from as low as 7% after 15 days (C. montrouzieri) to about 15–20% after five days (A. bipunctata) or 15 days (A. coriaria). For all three predators, there were no statistical differences between the mortality recorded in any of the treatment groups and the corresponding controls. These results indicate a lack of short- (A. bipunctata) and long-term (A. coriariaandC. montrouzieri) mortality associated with oral ingestion of Cry1Ab and Cry3Aa at the high dose tested (50 μg ml−1). We discuss the relevance of these findings for the ecology of beneficial Coleoptera and compatibility with Bt and GM Bt crops.
Relative expression of antigen B coding gene of bubaline isolates of Echinococcus granulosus in fertile and sterile cysts
Authors: Pan D. , Bera A.K. , Bandyopadhyay S. , Das S.K. , Bandyopadhyay S. , Bhattacharyya S. , Manna B. , De S. , Bhattacharya D.
Published: September 2009

This article communicates the relative quantification of five isoforms of antigen B (AgB) of Echinococcus granulosus. Relative expression of the AgB was quantified in active and inactive cysts. Cysts with germinal membrane, clear cyst fluid and protoscoleces showed uniform expression of the five isoforms and were utilized as control. Relative expression of AgB1 was the highest in cysts, where calcification has initiated. AgB2 and AgB4 were expressed more in fertile cysts irrespective of the condition of germinal membrane. The lowest expression of AgB3 was seen in calcified cysts. The relative expression of AgB5 could not be correlated with respect to the condition of the cyst because AgB5 is typically expressed by the adult stage of the parasite.
Enteric calicivirus and rotavirus infections in domestic pigs
Authors: HALAIHEL N. , MASÍA R. M. , FERNÁNDEZ-JIMÉNEZ M. , RIBES J. M. , MONTAVA R. , De BLAS I. , GIRONÉS O. , ALONSO J. L. , BUESA J.
Published: September 2009

We report the prevalence of rotavirus and calicivirus infections, along with their respective association with diarrhoea in the porcine population of the region of northern Spain. A total of 221 samples were collected at random from different farms in the region and from the main slaughterhouse facility in the city of Zaragoza. Faecal samples were scored as diarrhoeic or normal and grouped into five groups to match general farm management and age criteria: group I (suckling 0–4 weeks), group II (weaning >4–8 weeks), group III (transition >8–16 weeks), group IV (fattening >16–24 weeks) and group V (adults >24 weeks). Group A rotavirus detection and caliciviruses were investigated by reverse transcription–polymerase chain reaction (RT–PCR). Conventional RT–PCR was performed using primers designed to detect rotavirus group A, caliciviruses and/or human noroviruses. A real-time RT–PCR was carried out using TaqMan probes for genogroups GI and GII of noroviruses. Rotaviruses and caliciviruses were detected with an overall prevalence of 16·7% and 12·2%, respectively. Rotavirus detection in faecal samples was associated with both age and faecal consistency, being more frequent in piglets aged <8 weeks with odds ratios (ORs) equal to 4·3 and 4·9, respectively. Calicivirus shedding in faecal samples was homogenously distributed in all ages, showing no significant association with age or faecal consistency (OR 0·87 and 0·99, respectively). A selection of rotavirus-positive stools were genotyped by multiplex nested PCR. G10, P[6], G12 P[8], G9 [p8] and G4 P[23] genotype combinations were found. Three isolates showed a G3 genotype, but their VP4 gene could not be amplified. It should be noted that the G9 genotype was the major G genotype circulating during that period in Spain. None of the porcine samples was positive for norovirus by real-time RT–PCR, despite the ability of this technique to detect at least 18 human norovirus genotypes. Our data indicate that human noroviruses are unlikely to be circulating in the porcine population; however, sapoviruses have been found. Contrary to rotavirus infection, Calicivirus infection is asymptomatic. Specific primers to detect porcine noroviruses are needed.
Le passé surcomposé sous la loupe
Authors: WILMET MARC
Published: September 2009

Comment s'effectue la surcomposition d'un verbe français? Réponse: non pas en composant l'auxiliaire, ainsi qu'on l'affirme généralement, mais en composant l'auxilié. Combien existe-t-il alors de formes surcomposées avec avoir ou être? Réponse: autant que de formes composées moins une, soit neuf. La plus courante de ces formes est le passé surcomposé. Défini en termes de temps: présent bisantérieur, et en termes d'aspect: sécant bisextensif, il est schématisable sur la ligne du temps par le tracé ABCD (où A désigne le repère de l'actualité, B l'auxiliaire de surcomposition, C l'auxiliaire de composition, D l'auxilié). Ses emplois se ventilent en quatre types selon que la relation bijective D↔C↔B est saisie en D, en C (saisie par l'arrière de la relation D↔C et saisie par l'avant de la relation C↔B) ou en B.
Mapping the availability and accessibility of healthy food in rural and urban New Zealand – Te Wai o Rona: Diabetes Prevention Strategy
Authors: Wang Jing , Williams Margaret , Rush Elaine , Crook Nic , Forouhi Nita G , Simmons David
Published: September 2009

Objective

Uptake of advice for lifestyle change for obesity and diabetes prevention requires access to affordable ‘healthy’ foods (high in fibre/low in sugar and fat). The present study aimed to examine the availability and accessibility of ‘healthy’ foods in rural and urban New Zealand.

Design

We identified and visited (‘mapped’) 1230 food outlets (473 urban, 757 rural) across the Waikato/Lakes areas (162 census areas within twelve regions) in New Zealand, where the Te Wai O Rona: Diabetes Prevention Strategy was underway. At each site, we assessed the availability of ‘healthy’ foods (e.g. wholemeal bread) and compared their cost with those of comparable ‘regular’ foods (e.g. white bread).

Results

Healthy foods were generally more available in urban than rural areas. In both urban and rural areas, ‘healthy’ foods were more expensive than ‘regular’ foods after adjusting for the population and income level of each area. For instance, there was an increasing price difference across bread, meat, poultry, with the highest difference for sugar substitutes. The weekly family cost of a ‘healthy’ food basket (without sugar) was 29·1 % more expensive than the ‘regular’ basket ($NZ 176·72 v. $NZ 136·84). The difference between the ‘healthy’ and ‘regular’ basket was greater in urban ($NZ 49·18) than rural areas ($NZ 36·27) in adjusted analysis.

Conclusions

‘Healthy’ foods were more expensive than ‘regular’ choices in both urban and rural areas. Although urban areas had higher availability of ‘healthy’ foods, the cost of changing to a healthy diet in urban areas was also greater. Improvement in the food environment is needed to support people in adopting healthy food choices.
Along‐ and across‐axis variations in crustal thickness and structure at the Mid‐Atlantic Ridge at 5°S obtained from wide‐angle seismic tomography: Implications for ridge segmentation
Authors: Planert Lars , Flueh Ernst R. , Reston Timothy J.
Published: September 2009

Two end‐member styles of crustal accretion are observed at two adjacent spreading segments at the Mid‐Atlantic Ridge at 5°S: focused accretion to the segment center with rapid crustal thinning toward the transform in the northern segment and crustal thickening toward the transform at an oceanic core complex in the southern segment. Our results were obtained by tomographic inversion of wide‐angle seismic reflection and refraction data collected along three intersecting profiles. The segment north of the 5°S fracture zone is characterized by a well‐developed median valley with a pronounced seafloor bulge in the segment center. A discrete portion of anomalously low velocities (−0.4 to −0.5 km/s relative to average off‐axis structure) at depths of ∼2.5 km beneath this bulge is possibly related to the presence of elevated temperatures and perhaps small portions of partial melt. This suggests that this segment is currently in a magmatically active period, which is confirmed by the observation of fresh lava flows and ongoing high‐temperature hydrothermal activity at the seafloor. Close to the current spreading axis, the crust thins rapidly from 8.5 km beneath the segment center to less than 3 km beneath the transform fault which indicates that melt supply here is strongly focused to the segment center. The reduction in crustal thickness is almost exclusively accommodated by the thinning of velocity portions indicative of seismic layer 3. The transform fault is characterized by more uniform velocity gradients throughout the entire crustal section and very low upper mantle velocities of 7.2–7.3 km/s indicating that serpentinization could be as much as 25% at 3.5 km depth. In contrast, ∼4.1 Ma old crust of the northern segment shows only minor thinning from the segment center toward the segment end. Here, the transform is characterized by a normal seismic layer 2/3 transition suggesting robust melt supply to the segment end at those times. In the adjacent southern segment, the crust thickens from ∼2.5 km beneath the flank of an oceanic core complex to ∼5.0 km at the segment boundary. The observed changes in crustal thickness show a significant temporal and lateral variability in melt supply and suggest a more complex crustal emplacement process than predicted by models of focused melt supply to the segment centers.
Impact of the assimilation of Atmospheric Infrared Sounder radiance measurements on short‐term weather forecasts
Authors: McCarty Will , Jedlovec Gary , Miller Timothy L.
Published: September 2009

Advanced spaceborne instruments have the ability to improve the horizontal and vertical characterization of temperature and water vapor in the atmosphere through the explicit use of hyperspectral thermal infrared radiance measurements. The incorporation of these measurements into a data assimilation system provides a means to continuously characterize a three‐dimensional, instantaneous atmospheric state necessary for the time integration of numerical weather forecasts. Measurements from the National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) are incorporated into the grid point statistical interpolation (GSI) three‐dimensional variational (3D‐Var) assimilation system to provide improved initial conditions for use in a mesoscale modeling framework mimicking that of the operational North American Mesoscale (NAM) model. The methodologies for the incorporation of the measurements into the system are presented. Though the measurements have been shown to have a positive impact in global modeling systems, the measurements are further constrained in this system as the model top is physically lower than the global systems and there is no ozone characterization in the background state. For a study period, the measurements are shown to have positive impact on both the analysis state as well as subsequently spawned short‐term (0–48 h) forecasts, particularly in forecasted geopotential height and precipitation fields. At 48 h, height anomaly correlations showed an improvement in forecast skill of 2.3 h relative to a system without the AIRS measurements. Similarly, the equitable threat and bias scores of precipitation forecasts of 25 mm (6 h)−1 were shown to be improved by 8% and 7%, respectively.
Normal faulting along the southern margin of the Puna Plateau, northwest Argentina
Authors: Schoenbohm Lindsay M. , Strecker Manfred R.
Published: September 2009

Though orogen‐parallel shortening and vertical extension have dominated the tectonic evolution of the central Andes, a significant kinematic shift from horizontal contraction to extension appears to have occurred within the high Puna‐Altiplano Plateau, with the establishment of extension oblique to the orogen since late Miocene time. We present data from the southern margin of the Puna Plateau, NW Argentina, where new normal faults have been documented in the Fiambalá, Punta Negra, and La Quebrada areas. The unifying characteristics of these areas are that young normal faults reactivate or crosscut older thrust and reverse faults. The relationship between the faults and the late Miocene–Pliocene Punaschotter conglomerate suggests that the extensional faulting must be younger than 3.5 to 7 Ma. Existing data are incomplete but indicate that similar horizontal extension has occurred in many regions throughout the Puna‐Altiplano Plateau, while shortening continues along the plateau margins. Given the spatial and temporal distribution of this late Miocene to Pliocene kinematic shift, both lithospheric loss in the Puna Plateau and plateau‐wide gravitational extensional spreading enhanced by slowing of plate convergence rate could be responsible. The young, disorganized, horizontal extension in the Andes today may be the precursor to more pronounced extension such as observed on the Tibetan Plateau since mid‐Miocene time.
New reconstructions of streamflow variability in the South Saskatchewan River Basin from a network of tree ring chronologies, Alberta, Canada
Authors: Axelson Jodi N. , Sauchyn David J. , Barichivich Jonathan
Published: September 2009

In western Canada growing demand for water resources has increased vulnerability to hydrological drought. The near full allocation of water supplies in the Oldman and Bow River subbasins of the South Saskatchewan River Basin has resulted in a moratorium on new surface water licenses. In this region, short instrumental records limit the detection of long‐term hydrological variability. To extend the historical record, we collected 14 new moisture‐sensitive tree ring chronologies and reconstructed the average October through September flow of the Oldman (1618–2004) and South Saskatchewan (SSR) (1400–2004) rivers. Our SSR proxy record updates a previously published reconstruction. While the 20th century is representative of drought frequency over the long term, droughts are of greater severity and duration in the preinstrumental proxy record. A spectral analysis of the reconstructed flows revealed quasiperiodic cycles at interannual to multidecadal scales.
Evidence of sediment resuspension by island trapped waves
Authors: Jordi Antoni , Basterretxea Gotzon , Wang Dong‐Ping
Published: September 2009

Six months of current and acoustic backscatter data from an acoustic Doppler current profiler (ADCP) moored in the shelf off Mallorca (Balearic Islands, Mediterranean Sea) were analyzed. The presence of island trapped waves (ITWs) was determined by correspondence of energetic subinertial peaks in the alongshore current spectra with theoretical wave modes. Although currents in this area averaged 0.06 m/s and rarely exceeded 0.5 m/s, an intense episode with currents larger than 1 m/s was observed between March 8 and 11, 2007. Our analysis demonstrates that ITWs generated by local wind forcing were responsible for such currents, causing significant sediment resuspension on those days. It is suggested that even moderate wind pulses can induce important resuspension along the shelf by generating ITWs. This could be an overlooked mechanism of coupling between atmospheric and shelf circulation with significant implications for sediment dynamics and biogeochemical cycles.
Atmospheric aerosol variations at Okinawa Island in Japan observed by MAX‐DOAS using a new cloud‐screening method
Authors: Takashima H. , Irie H. , Kanaya Y. , Shimizu A. , Aoki K. , Akimoto H.
Published: September 2009

Atmospheric aerosol profile observations using Multi Axis Differential Optical Absorption Spectroscopy (MAX‐DOAS) have been conducted at Cape Hedo (26.87°N, 128.25°E), the northernmost point of Okinawa Island in Japan, since 30 March 2007. Comparisons of aerosol extinction at 476 nm by MAX‐DOAS with ground‐based lidar measurements for cloud‐free conditions over more than 1 year showed good agreement on both seasonal and intraseasonal time scales, with differences of less than 30% on average for 0–1 km. Agreement between aerosol optical depths retrieved by MAX‐DOAS and the sky radiometer was also observed during the same period, with differences of less than 30% in most cases. A cloud‐screening method using MAX‐DOAS data based on the physical properties of clouds was developed to evaluate aerosol variations, focused primarily on transboundary air pollution below low‐level clouds, using relative humidity derived from MAX‐DOAS H2O measurements and the MAX‐DOAS color index, defined as the ratio of the intensities at 500 and 380 nm. This method consists of two steps: cloud screening in the troposphere using the color index and cloud‐base height determination from the relative humidity. The former was consistent with lidar cloud screening at 0–6 km, and for the latter, a strong negative correlation between the lidar cloud‐base height and the relative humidity was found. Using this unique cloud‐screening method, we investigated aerosol variations at 0–1 km. A clear annual minimum was found in August–September, with low variability in relation to oceanic sources of clean air masses, whereas the maximum was found in November–May, with large variability in relation to continental sources of polluted air masses. This new cloud‐screening method can be useful for evaluating aerosols below clouds, particularly during the northern winter at Cape Hedo, when and where transboundary air pollution from the Asian continent below low‐level clouds frequently occurs in conjunction with strong westerly winds.
Deterministic versus stochastic trends: Detection and challenges
Authors: Fatichi S. , Barbosa S. M. , Caporali E. , Silva M. E.
Published: September 2009

The detection of a trend in a time series and the evaluation of its magnitude and statistical significance is an important task in geophysical research. This importance is amplified in climate change contexts, since trends are often used to characterize long‐term climate variability and to quantify the magnitude and the statistical significance of changes in climate time series, both at global and local scales. Recent studies have demonstrated that the stochastic behavior of a time series can change the statistical significance of a trend, especially if the time series exhibits long‐range dependence. The present study examines the trends in time series of daily average temperature recorded in 26 stations in the Tuscany region (Italy). In this study a new framework for trend detection is proposed. First two parametric statistical tests, the Phillips‐Perron test and the Kwiatkowski‐Phillips‐Schmidt‐Shin test, are applied in order to test for trend stationary and difference stationary behavior in the temperature time series. Then long‐range dependence is assessed using different approaches, including wavelet analysis, heuristic methods and by fitting fractionally integrated autoregressive moving average models. The trend detection results are further compared with the results obtained using nonparametric trend detection methods: Mann‐Kendall, Cox‐Stuart and Spearman'sρtests. This study confirms an increase in uncertainty when pronounced stochastic behaviors are present in the data. Nevertheless, for approximately one third of the analyzed records, the stochastic behavior itself cannot explain the long‐term features of the time series, and a deterministic positive trend is the most likely explanation.
Synthesis of a germanium analogue of a dithiocarboxylic acid anhydride from the Ge(i) pyridyl-1-azaallyl dimer
Authors: Leung Wing-Por , Chiu Wang-Kin , Chong Kim-Hung , Mak Thomas C. W.
Published: September 2009

The reaction of germanium(i) pyridyl-1-azaallyl dimer [(RGe)2] (2) [R = {N(SiMe3)C(Ph)C(SiMe3)(C5H4N-2)}] with an excess of elemental sulfur afforded an unprecedented germanium analogue of a dithiocarboxylic acid anhydride [{Ge(S)R}2S] (4). The X-ray structures of 2 and 4 have been determined.
Thermal conductivity and phonon transport properties of silicon using perturbation theory and the environment-dependent interatomic potential
Authors: Pascual-Gutiérrez José A. , Murthy Jayathi Y. , Viskanta Raymond
Published: September 2009

Silicon thermal conductivities are obtained from the solution of the linearized phonon Boltzmann transport equation without the use of any parameter-fitting. Perturbation theory is used to compute the strength of three-phonon and isotope scattering mechanisms. Matrix elements based on Fermi’s golden rule are computed exactly without assuming either average or mode-dependent Grüeisen parameters, and with no underlying assumptions of crystal isotropy. The environment-dependent interatomic potential is employed to describe the interatomic force constants and the perturbing Hamiltonians. A detailed methodology to accurately find three-phonon processes satisfying energy- and momentum-conservation rules is also described. Bulk silicon thermal conductivity values are computed across a range of temperatures and shown to match experimental data very well. It is found that about two-thirds of the heat transport in bulk silicon may be attributed to transverse acoustic modes. Effective relaxation times and mean free paths are computed in order to provide a more complete picture of the detailed transport mechanisms and for use with carrier transport models based on the Boltzmann transport equation.
Theory of high field carrier transport and impact ionization in wurtzite GaN. Part I: A full band Monte Carlo model
Authors: Bertazzi Francesco , Moresco Michele , Bellotti Enrico
Published: September 2009

High field electron and hole transport in wurtzite phase GaN is studied using an ensemble Monte Carlo method. The model includes the details of the full band structure derived from nonlocal empirical pseudopotential calculations. The nonpolar carrier-phonon interaction is treated within the framework of the rigid pseudoion approximation using ab initio techniques to determine the phonon dispersion relation. The calculated carrier-phonon scattering rates are consistent with the electronic structure and the phonon dispersion relation thus removing adjustable parameters such as deformation potential coefficients. The impact ionization transition rate is computed based on the calculated electronic structure and the corresponding wave-vector dependent dielectric function. The complex band structure of wurtzite GaN requires the inclusion of band-to-band tunneling effects that are critical at high electric fields. The electric-field-induced interband transitions are investigated by the direct solution of the time dependent multiband Schrödinger equation. The multiband description of the transport predicts a considerable increase in the impact ionization coefficients compared to the case in which tunneling is not considered. In the second part of this work it will be shown that the proposed numerical model correctly predicts the carrier multiplication gain and breakdown voltage of a variety of GaN avalanche photodetectors that have been recently fabricated by several research groups.
Validation of on- and off-axis neutral beam current drive against experiment in DIII-D
Authors: Park J. M. , Murakami M. , Petty C. C. , Heidbrink W. W. , Osborne T. H. , Holcomb C. T. , Van Zeeland M. A. , Prater R. , Luce T. C. , Wade M. R. , Austin M. E. , Brooks N. H. , Budny R. V. , Challis C. D. , DeBoo J. C. , deGrassie J. S. , Ferron J. R. , Gohil P. , Hobirk J. , Hollmann E. M. , Hong R. M. , Hyatt A. W. , Lohr J. , Lanctot M. J. , Makowski M. A. , McCune D. C. , Politzer P. A. , St John H. E. , Suzuki T. , West W. P. , Unterberg E. A. , Yu J. H.
Published: September 2009

Neutral beam current drive (NBCD) experiments in DIII-D using vertically shifted plasmas to move the current drive away from the axis have clearly demonstrated robust off-axis NBCD. Time-dependent measurements of magnetic field pitch angles by the motional Stark effect diagnostic are used to obtain the evolution of the poloidal magnetic flux, which indicates a broad off-axis NBCD profile with a peak at about half the plasma minor radius. In most cases, the measured off-axis NBCD profile is consistent with calculations using an orbit-following Monte Carlo code for the beam ion slowing down including finite-orbit effects provided there is no large-scale magnetohydrodynamic activity such as Alfvén eigenmodes modes or sawteeth. An alternative analysis method shows good agreement between the measured pitch angles and those from simulations using transport-equilibrium codes. Two-dimensional image of Doppler-shifted fast ion Dα light emitted by neutralized energetic ions shows clear evidence for a hollow profile of beam ion density, consistent with classical beam ion slowing down. The magnitude of off-axis NBCD is sensitive to the alignment of the beam injection relative to the helical pitch of the magnetic field lines. If the signs of toroidal magnetic field and plasma current yield the proper helicity, both measurement and calculation indicate that the efficiency is as good as on-axis NBCD because the increased fraction of trapped electrons reduces the electron shielding of the injected ion current, in contrast with electron current drive schemes where the trapping of electrons degrades the efficiency. The measured off-axis NBCD increases approximately linearly with the injection power, although a modest amount of fast ion diffusion is needed to explain an observed difference in the NBCD profile between the measurement and the calculation at high injection power.
Presence of left-handedness and negative refraction in antiferromagnetic/ionic-crystal multilayered films
Authors: Song Yuling , Ta Jinxing , Li Hua , Wang Xuan-Zhang
Published: September 2009

We present a simple structure of multilayered film that possesses left-handedness-like and negative refraction at infrared frequencies. It periodically consists of antiferromagnetic (AF) and ionic-crystal (IC) layers, where IC material has a transverse optical phonon frequency near and below the AF resonant frequency. We calculated the angle between the energy flow and wave vector of a plane wave in the film and its refraction angle, and found an analytical condition under which both left-handedness and negative refraction appear in the multilayered film, and the negative refraction phenomenon disappears when AF layers are thinner than IC. Numerical simulation results verify these analytical findings.
Experimental characterization and theoretical modeling of the strain effect on the evolution and interband transitions of InAs quantum dots grown on InxGa1−xAs (0.0⩽x⩽0.3) metamorphic pseudosubstrates on GaAs wafers
Authors: Ghanad-Tavakoli Shahram , Naser Mohamed A. , Thompson David A. , Jamal Deen M.
Published: September 2009

Experimental characterization and theoretical study of the interband transitions of self-assembled InAs quantum dots (QDs) grown on metamorphic pseudosubstrates of InxGa1−xAs (0.0⩽x⩽0.3) are reported. The effect of the varying underlying strain on the size distribution of InAs QDs and their photoluminescence emission wavelength is investigated by employing different substrate compositions. Atomic force microscopy images of the QDs show that the ratio of the height/lateral diameter of the QDs decreases with decreasing strain and the photoluminescence of the buried InAs QDs shows that the peak wavelength redshifts with increasing In mole fraction of the underlying pseudosubstrates. A theoretical model based on the Green’s function technique is used to calculate the density of states (DOS) of the QDs for the different samples based on the measured dot geometries. From the DOS, the electron and hole energy levels can be obtained, yielding the possible interband transitions. Good agreement between the model and the experimental results is obtained by allowing for Ga incorporation, from the substrate and barrier layers, into the InAs QDs and it is found that the necessary Ga mole fraction varies linearly with the Ga mole fraction in the underlying InxGa1−xAs pseudosubstrate.
Characterization of thick film poly(triarylamine) semiconductor diodes for direct x-ray detection
Authors: Intaniwet Akarin , Mills Christopher A. , Shkunov Maxim , Thiem Heiko , Keddie Joseph L. , Sellin Paul J.
Published: September 2009

Thick film (≥5 μm thick) semiconducting polymer diodes incorporating poly(triarylamine) (PTAA) have been produced and applied as direct x-ray detectors. Experiments determined that a rectifying diode behavior persists when increasing the thickness of the active layer above typical thin film thicknesses (<1 μm), and the electrical conduction mechanism of the diodes has been identified. Direct current and photoconductivity measurements on indium tin oxide/poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate)/PTAA/metal diodes confirm that carrier conduction occurs via a Poole–Frenkel mechanism. The energy band structure of diodes (having gold or aluminum top electrodes) has been elucidated and used to explain the resulting electrical characteristics. Theoretical calculations show that, upon irradiation with x-rays, the diode quantum efficiency increases with increasing polymer film thickness. The diodes produced here display characteristics similar to their thin film analogs, meaning that they may be operated in a similar way and therefore may be useful for radiation dosimetry applications. Upon irradiation, the diodes produce an x-ray photocurrent that is proportional to the dose, thus demonstrating their suitability for direct x-ray detectors. The x-ray photocurrent remains the same in a device after a cumulative exposure of 600 Gy and after aging for 6 months.
Intrinsic and extrinsic diffusion of indium in germanium
Authors: Kube R. , Bracht H. , Chroneos A. , Posselt M. , Schmidt B.
Published: September 2009

Diffusion experiments with indium (In) in germanium (Ge) were performed in the temperature range between 550 and 900 °C. Intrinsic and extrinsic doping levels were achieved by utilizing various implantation doses. Indium concentration profiles were recorded by means of secondary ion mass spectrometry and spreading resistance profiling. The observed concentration independent diffusion profiles are accurately described based on the vacancy mechanism with a singly negatively charged mobile In-vacancy complex. In accord with the experiment, the diffusion model predicts an effective In diffusion coefficient under extrinsic conditions that is a factor of 2 higher than under intrinsic conditions. The temperature dependence of intrinsic In diffusion yields an activation enthalpy of 3.51 eV and confirms earlier results of Dorner et al. [Z. Metallk. 73, 325 (1982)]. The value clearly exceeds the activation enthalpy of Ge self-diffusion and indicates that the attractive interaction between In and a vacancy does not extend to third nearest neighbor sites which confirms recent theoretical calculations. At low temperatures and high doping levels, the In profiles show an extended tail that could reflect an enhanced diffusion at the beginning of the annealing.
Growth of single-crystalline zirconium diboride thin film on sapphire
Authors: Bera Sambhunath , Sumiyoshi Yuichiro , Yamada-Takamura Yukiko
Published: September 2009

Conducting and reflecting thin film of ZrB2, which has lattice mismatch of only 0.6% to GaN, was grown epitaxially on sapphire substrate [α-Al2O3(0001)] via thermal decomposition of Zr(BH4)4. In situ reflection high energy electron diffraction and ex situ x-ray diffraction analyses indicate that the epitaxial relationship is singular, i.e., ZrB2[0001]∥Al2O3[0001] and ZrB2[112¯0]∥Al2O3[101¯0]. X-ray photoelectron spectroscopy and scanning tunneling microscopy revealed that the oxide-free surface could be recovered by heating the film at approximately 750 °C under ultrahigh vacuum, which demonstrates its suitability as a template for the growth of nitride semiconductors.
Chemical structure of the (Zn1−x,Mgx)O/CuIn(S,Se)2 interface in thin film solar cells
Authors: Erfurth F. , Hußmann B. , Schöll A. , Reinert F. , Grimm A. , Lauermann I. , Bär M. , Niesen Th. , Palm J. , Visbeck S. , Weinhardt L. , Umbach E.
Published: September 2009

The formation of the interface between a magnetron sputtered (Zn1−x,Mgx)O buffer layer and a CuIn(S,Se)2 absorber in thin film solar cells has been investigated by x-ray photoelectron spectroscopy and x-ray induced Auger electron spectroscopy. Detailed analysis of the spectra shows the incorporation of Zn into the absorber surface in the initial stage of the deposition process forming ZnS and/or ZnSe bonds. As a result we find the buffer layer to be Zn-depleted near the interface.
Three-dimensional fluid simulations of a simple magnetized toroidal plasma
Authors: Ricci Paolo , Rogers B. N.
Published: September 2009

Three-dimensional fluid simulations are performed in a simple magnetized toroidal plasma, in which vertical and toroidal magnetic fields create helicoidal magnetic field lines that terminate on the torus vessel. The simulations are carried out in the three-dimensional flux tube that wraps around the torus and are able to describe both interchange and drift-wave dynamics. The presence of different turbulence regimes is pointed out; in particular, it is shown that turbulence can be quenched by either a sufficiently large plasma source, or a sufficiently small vertical field, or a sufficiently high parallel resistivity. The simulations considered herein reveal that interchange turbulence dominates over the drift-wave dynamics. Considering the experimental observations, we finally discuss the limitations of the present model.
Cross sections and photoelectron angular distributions in photodetachment from negative ions using equation-of-motion coupled-cluster Dyson orbitals
Authors: Oana C. Melania , Krylov Anna I.
Published: September 2009

We report total and differential cross sections for photodetachment from negative ions using Dyson orbitals calculated from equation-of-motion coupled-cluster wave functions and free wave description of the detached electron. The energy dependence of the cross sections is reproduced well, however, the accuracy of absolute values varies. For F−, C−, NH2−, and H−, the calculated cross sections are within the error bars from the experimental values, whereas the errors for Li− and OH− are about 20%. The largest errors are observed for O− and O2− for which the calculated cross sections differ from the experimental ones by factors of 3 and 2, respectively. Calculated anisotropy parameters for atomic anions exhibit too slow decrease, which suggests that the diffuseness of the computed Dyson orbitals is underestimated. Moreover, in the asymptotic region, the orbitals exhibit artifactual oscillations probably due to the limitations of Gaussian basis sets. The analysis of the trends in the experimental anisotropy parameters suggests that the interaction of the detached electron with the core, which is neglected in the present model, is important.
Magnetic tunnel junction based microwave detector
Authors: Fan X. , Cao R. , Moriyama T. , Wang W. , Zhang H. W. , Xiao John Q.
Published: September 2009

We investigated the tunneling magnetoresistance change in magnetic tunnel junctions in the presence of external microwaves. The changing relative angle between the free layer and the pinned layer results in a rectification of the average resistance change. Due to its miniature size and its sensitivity to the microwave magnetic field, the magnetic tunnel junction could be utilized as a microwave power sensor with the ability to detect microwave frequencies. Studying microwave power and bias current dependencies reveals desired sensor features with linear responses and enhanced signal levels.