bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuroticism, recall bias and attention bias for valenced probes: a twin study
Authors: Rijsdijk F. V. , Riese H. , Tops M. , Snieder H. , Brouwer W. H. , Smid H. G. O. M. , Ormel J.
Published: April 2008

Background

Prior research on the nature of the vulnerability of neuroticism to psychopathology suggests biases in information processing towards emotional rather than neutral information. It is unclear to what extent this relationship can be explained by genetic or environmental factors.

Method

The genetic relationship between a neuroticism composite score and free recall of pleasant and unpleasant words and the reaction time on negative probes (dot-probe task) was investigated in 125 female twin pairs. Interaction effects were modelled to test whether the correlation between neuroticism and cognitive measures depended on the level of the neuroticism score.

Results

The only significant correlation was between neuroticism and the proportion of recalled unpleasant words (heritability is 30%), and was only detectable at the higher end of the neuroticism distribution. This interaction effect seems to be due to environmental effects that make people in the same family more similar (e.g. parental discipline style), rather than genetic factors. An interesting sub-finding was that faster reaction times for left versus right visual field probes in the dot-probe task suggest that cognitive processing in the right hemisphere is more sensitive to subliminal (biologically relevant) cues and that this characteristic is under substantial genetic control (49%). Individual differences in reaction times on right visual field probes were due to environmental effects only.

Conclusions

There is no evidence that the predisposition of individuals to focus on negative (emotional) stimuli is a possible underlying genetic mechanism of neuroticism.
Affective modulation of external misattribution bias in source monitoring in schizophrenia
Authors: Costafreda S. G. , Brébion G. , Allen P. , McGuire P. K. , Fu C. H. Y.
Published: April 2008

Background

Schizophrenic patients tend to attribute internal events to external agents, a bias that may be linked to positive symptoms. We investigated the effect of emotional valence on the cognitive bias.

Method

Male schizophrenic subjects (n=30) and an experimenter alternatively produced neutral and negative words. The subject then decided whether he or the experimenter had generated the item.

Results

External misattributions were more common than self-misattributions, and the bias was greater for patients with active hallucinations and delusions relative to patients in remission. Actively psychotic patients but not patients in remission were more likely to generate external misattributions with negative relative to neutral words.

Conclusions

Affective modulation of the externalizing cognitive bias in source monitoring is evident in patients with hallucinations and delusions.
Resonant acceleration of electrons by intense circularly polarized Gaussian laser pulses
Authors: Niu H.Y. , He X.T. , Qiao B. , Zhou C.T.
Published: April 2008

Resonant acceleration of plasma electrons in combined circularly polarized Gaussian laser fields and self-generated quasistatic fields has been investigated theoretically and numerically. The latter includes the radial quasistatic electric field, the azimuthal quasistatic magnetic field and the axial one. The resonant condition is theoretically given and numerically testified. The results show some of the resonant electrons are accelerated to velocities larger than the laser group velocity and thus gain high energy. For peak laser intensity I0 = 1 × 1020 W cm−2 and plasma density n0 = 0.1ncr, the relativistic electron beam with energies increased from 207 MeV to 262 MeV with a relative energy width around 24% and extreme low beam divergence less than 1° has been obtained. The effect of laser intensity and plasma density on the final energy gain of resonant electrons is also investigated.
Non-adiabatic cluster expansion after ultrashort laser interaction
Authors: Faenov A.Ya. , Magunov A.I. , Pikuz T.A. , Skobelev I.Yu. , Giulietti D. , Betti S. , Galimberti M. , Gamucci A. , Giulietti A. , Gizzi L.A. , Labate L. , Levato T. , Tomassini P. , Marques J.R. , Bourgeois N. , Dobosz dufrenoy S. , Ceccotti T. , Monot P. , Reau F. , Popescu H. , D'oliveira P. , Martin PH. , Fukuda Y. , Boldarev A.S. , Gasilov S.V. , Gasilov V.A.
Published: April 2008

We used X-ray spectroscopy as a diagnostic tool for investigating the properties of laser-cluster interactions at the stage in which non-adiabatic cluster expansion takes place and a quasi-homogeneous plasma is produced. The experiment was carried out with a 10 TW, 65 fs Ti:Sa laser focused on CO2 cluster jets. The effect of different laser-pulse contrast ratios and cluster concentrations was investigated. The X-ray emission associated to the Rydberg transitions allowed us to retrieve, through the density and temperature of the emitting plasma, the time after the beginning of the interaction at which the emission occurred. The comparison of this value with the estimated time for the “homogeneous” plasma formation shows that the degree of adiabaticity depends on both the cluster concentration and the pulse contrast. Interferometric measurements support the X-ray data concerning the plasma electron density.
The role of hollow atoms in the spectra of an ultrashort-pulse-laser-driven Ar cluster target
Authors: Colgan J. , Abdallah J. , Faenov A. Y. , Pikuz T. A. , Skobelev I. Y. , Fortov V. E. , Fukuda Y. , Akahane Y. , Aoyama M. , Inoue N. , Yamakawa K.
Published: April 2008

An investigation is made of the role of hollow atoms in the spectra of an ultrashort-pulse-laser-driven Ar cluster target. Experimental measurements are presented from an Ar cluster-gas target using short-pulse lasers with various intensities, durations, and contrasts. Calculations in support of these measurements have been performed using a detailed atomic kinetics model with the ion distributions found from solution of the time-dependent rate equations. The calculations are in good agreement with the measurements and the role of hollow atoms in the resulting complicated spectra is analyzed. It is demonstrated that, although the presence of hollow atoms is estimated to add only around 2% to the total line emission, signatures of hollow atom spectra can be identified in the calculations, which are qualitatively supported by the experimental measurements.
Development of laser-induced breakdown spectroscopy for microanalysis applications
Authors: Godwal Y. , Taschuk M.T. , Lui S.L. , Tsui Y.Y. , Fedosejevs R.
Published: April 2008

Laser induced breakdown spectroscopy is a fast non-contact technique for the analysis of the elemental composition of any sample. Our focus is to advance this technique into a regime where we use pulse energies below 100 µJ. This regime is referred to as micro-laser-induced breakdown spectroscopy or µLIBS. At present we have concentrated on two application areas : (1) The imaging of latent fingerprints and (2) the extension to laser ablation followed by laser-induced fluorescence (LA-LIF) for very high sensitivity analysis of contaminants in water. Preliminary pulse emission scaling of Na in latent fingerprints has been investigated for ~130 fs, 266 nm pulses with energies below 15 µJ. The lowest energy for reliable single shot detection of Na is approximately 3.5 µJ. A 2D map of a fingerprint on a Si wafer has been successfully demonstrated using 5 µJ pulses. In LA-LIF the detection sensitivity of micro-laser-induced breakdown spectroscopy (µLIBS) is improved by coupling it with a second resonant probe pulse. This technique was investigated for the detection of Pb at low concentrations when ablated by 266 nm, 170 µJ pulses. After a short delay the resulting plume was re-excited with a nanosecond laser pulse tuned to a specific transition of Pb. In the case of the resonant dual-pulse LIBS the limit of detection was found to be approximately 60 ppb for Pb in water for 1000 shots. It is expected that this result could be implemented with fiber or microchip lasers with multi-kHz repetition rates and fiber Bragg grating tuning elements. The results are promising for the development of portable µLIBS water monitoring systems and portable fingerprint scanners.
Gauss paragraphs of classical links and a characterization of virtual link groups
Authors: KURLIN VITALIY
Published: April 2008

A classical link in 3-space can be represented by a Gauss paragraph encoding a link diagram in a combinatorial way. A Gauss paragraph may code not a classical link diagram, but a diagram with virtual crossings. We present a criterion and a linear algorithm detecting whether a Gauss paragraph encodes a classical link. We describe Wirtinger presentations realizable by virtual link groups.
Interrogating the genome to understand oestrogen-receptor-mediated transcription
Authors: Dietz Sara C. , Carroll Jason S.
Published: April 2008

Defining transcription mediated by the oestrogen (estrogen) receptor (ER) in breast cancer cell models has been an area of interest for many years. Initial studies focused on promoter regions of putative target genes and revealed significant insight into the basis of ER binding to DNA. More recently, the complexities of ER transcription are starting to become apparent. It is now clear that ER can regulate gene targets from significant distances and that cooperating transcription factors play an integral role in ER activity. It is also clear that the sequence information defining an in vivo ER-binding site is more complicated than initially thought. However, contemporary genomic tools based on chromatin immunoprecipitation (ChIP) – such as ChIP-on-chip and ChIP–sequencing – and gene expression profiling have allowed us to redefine the underlying properties of ER biology on a genomic scale. The advances in technology that have permitted a better understanding of how and where ER can bind to DNA are discussed in this review. The possible clinical implications of these findings for understanding the role of oestrogen in breast cancer are also briefly considered.
Effects of Organic Phase, Fermentation Media, and Operating Conditions on Lactic Acid Extraction
Authors: Hossain Md Monwar , Maisuria J. L.
Published: April 2008

Lactic acid has extensive uses in the food, pharmaceutical, cosmetic and chemical industry. Lately, its use in producing biodegradable polymeric materials (polylactate) makes the production of lactic acid from fermentation broths very important. The major part of the production cost accounts for the cost of separation from very dilute reaction media where productivity is low as a result of the inhibitory nature of lactic acid. The current method of extraction/separation is both expensive and unsustainable. Therefore, there is great scope for development of alternative technology that will offer efficiency, economic, and environmental benefits. One of the promising technologies for recovery of lactic acid from fermentation broth is reactive liquid‐liquid extraction. In this paper the extraction and recovery of lactic acid based on reactive processes is examined and the performance of a hydrophobic microporous hollow‐fiber membrane module (HFMM) is evaluated. First, equilibrium experiments were conducted using organic solutions consisting of Aliquat 336/trioctylamine (as a carrier) and tri‐butyl phosphate (TBP)/sunflower oil (as a solvent) The values of the distribution coefficient were obtained as a function of feed pH, composition of the organic phase (ratio of carrier to solvent), and temperature (range 8–40 °C). The optimum extraction was obtained with the organic phase consisting of a mixture of 15wt % tri‐octylamine (TOA) and 15% Aliquat 336 and 70% solvent. The organic phase with TBP performed best but is less suitable because of its damaging properties (toxicity and environmental impact) and cost. Sunflower oil, which performed moderately, can be regarded as a better option as it has many desirable characteristics (nontoxic, environment‐ and operator‐friendly) and it costs much less. The percentage extraction was approximately 33% at pH 6 and at room temperature (can be enhanced by operating at higher temperatures) at a feed flow rate of 15–20 L/h. These results suggest that the hollow‐fiber membrane process yields good percentage extraction at the fermentation conditions and its in situ application could improve the process productivity by suppressing the inhibitory effect of lactic acid.
Radiocarbon‐based carbon source quantification of anomalous isotopic foraminifera in last glacial sediments in the western North Pacific
Authors: Uchida Masao , Ohkushi Ken'ichi , Kimoto Katsunori , Inagaki Fumio , Ishimura Toyoho , Tsunogai Urumu , TuZino Taqumi , Shibata Yasuyuki
Published: April 2008

A previous study interpreted extremely 13C‐depleted excursions of planktonic and benthic foraminifera in last glacial sediments (17,500 to 25,400 cal years B.P.) of the core retrieved from off Shimokita Peninsula and off Hokkaido, Japan, as evidence for periodic releases of methane, arising from the dissociation of methane hydrate. To better understand the formation process of the 13C‐depleted excursions, we conducted high‐resolution natural radiocarbon measurements and biogeochemical analyses. We found highly depleted 13C excursions ranging from −10.2‰ to −1.6‰ and −6.8‰ to −1.6‰ in planktonic and benthic foraminifera, respectively. Most of the foraminiferal tests in these horizons were brown, most likely as a result of postdepositional alteration, reflecting the formation of authigenic carbonate on the surface of tests. These alterations were also supported by high levels of Mg‐calcite and the acid‐leaching test for anomalous foraminifera. To evaluate the carbon sources in the altered foraminifera tests, we quantified the relative contributions of 14C‐free methane‐derived carbon sources to the formation of authigenic carbonates in foraminifera with depleted 13C excursions using a coupled mass balance isotopic model (14C/C and 13C/12C). The radiocarbon ages of both planktonic and benthic 13C‐depleted foraminifera were approximately 600 to 2000 years older than those of normal tests from nearby horizons. The relative contributions of authigenic carbonates derived from the methane oxidizing process reached to ∼22 wt% for planktonic foraminifera and ∼15 wt% for benthic foraminifera. The δ13C values of methane calculated from the mass balance model were between −29‰ and −68‰ for planktonic foraminifera and between −40‰ and −108‰ for benthic foraminifera, consistent with δ13C values reported for thermogenic and abiogenic methane in global methane hydrate reservoirs. These data consistently suggest that methane‐related drastic environmental change occurred in the horizons that included δ13C anomalies. This study provides important information for interpreting geological records of the methane hydrate instability associated with climate.
Antarctic sediment chronology by programmed‐temperature pyrolysis: Methodology and data treatment
Authors: Rosenheim Brad E. , Day Mary Beth , Domack Eugene , Schrum Heather , Benthien Albert , Hayes John M.
Published: April 2008

We report a detailed programmed‐temperature pyrolysis/combustion methodology for radiocarbon (14C) dating of Antarctic sub‐ice shelf sediments. The method targets the autochthonous organic component in sediments that contain a distribution of acid‐insoluble organic components from several sources of different ages. The approach has improved sediment chronology in organic‐rich sediments proximal to Antarctic ice shelves by yielding maximum age constraints significantly younger than bulk radiocarbon dates from the same sediment horizons. The method proves adequate in determining isotope ratios of the pre‐aged carbon end‐member; however, the isotopic compositions of the low‐temperature measurements indicate that no samples completely avoided mixing with some proportion of pre‐aged organic material. Dating the unresolved but desired young end‐member must rely on indirect methods, but a simple mixing model cannot be developed without knowledge of the sedimentation rate or comparable constraints. A mathematical approach allowing for multiple mixing components yields a maximum likelihood age, a first‐order approximation of the relative proportion of the autochthonous component, and the temperature at which allochthonous carbon begins to volatilize and mix with the autochthonous component. It is likely that our estimation of the cutoff temperature will be improved with knowledge of the pyrolysis kinetics of the major components. Chronology is improved relative to bulk acid‐insoluble organic material ages from nine temperature interval dates down to two, but incorporation of inherently more pre‐aged carbon in the first division becomes more apparent with fewer and larger temperature intervals.
Land use change effects on trace gas fluxes in the forest margins of Central Sulawesi, Indonesia
Authors: Veldkamp Edzo , Purbopuspito Joko , Corre Marife D. , Brumme Rainer , Murdiyarso Daniel
Published: April 2008

Land use changes and land use intensification are considered important processes contributing to the increasing concentrations of the greenhouse gases nitrous oxide (N2O) and methane (CH4) and of nitric oxide (NO), a precursor of ozone. Studies on the effects of land use changes and land use intensification on soil trace gas emissions were mostly conducted in Latin America and only very few in Asia. Here we present results from Central Sulawesi where profound changes in land use and cultivation practices take place: traditional agricultural practices like shifting cultivation and slash‐and‐burn agriculture are replaced by permanent cultivation systems and introduction of income‐generating cash crops like cacao. Our results showed that N2O emissions were higher from cacao agroforestry (35 ± 10 μg N m−2 h−1) than maize (9 ± 2 μg N m−2 h−1), whereas intermediate rates were observed from secondary forests (25 ± 11 μg N m−2 h−1). NO emissions did not differ among land use systems, ranging from 12 ± 2 μg N m−2 h−1 for cacao agroforestry and secondary forest to 18 ± 2 μg N m−2 h−1 for maize. CH4 uptake was higher for maize (−30 ± 4 μg C m−2 h−1) than cacao agroforestry (−18 ± 2 μg C m−2 h−1) and intermediate rates were measured from secondary forests (−25 ± 4 μg C m−2 h−1). Combining these data with results from other studies in this area, we present chronosequence effects of land use change on trace gas emissions from natural forest, through maize cultivation, to cacao agroforestry (with or without fertilizer). Compared to the original forests, this typical land use change in the study area clearly led to higher N2O emissions and lower CH4 uptake with age of cacao agroforestry systems. We conclude that this common land use sequence in the area combined with the increasing use of fertilizer will strongly increase soil trace gas emissions. We suggest that the future hot spot regions of high N2O (and to a lesser extend NO) emissions in the tropics are those areas where climatic and edaphic conditions allow for intensive agriculture. This scenario is probably preferable over the alternative of agriculture extensification, which would imply a dramatic increase in deforestation rates with accompanying CO2 emissions.
Evaluating Mg/Ca ratios as a temperature proxy in the estuarine oyster, Crassostrea virginica
Authors: Surge Donna , Lohmann Kyger C
Published: April 2008

We examined the potential utility of Mg/CaSHELL ratios recorded in shells of the estuarine oyster Crassostrea virginica as a temperature proxy because oxygen isotope ratios (δ18O) in estuaries are complicated by the simultaneous fluctuation in temperature and salinity, whereas Mg/CaWATER ratios are assumed to be constant above 10 practical salinity units (psu). We tested this assumption and observed a slight mixing effect between 10 psu and normal marine values emphasizing the need to test this assumption in estuarine settings. Microsamples of shell carbonate were analyzed for δ18O, δ13C, and Mg/Ca ratios. Measured δ18OSHELL and δ13CSHELL were compared to predicted values to assign dates to shell samples. Once samples and dates were aligned, corresponding temperature and salinity for a particular sample were known, enabling comparison of Mg/CaSHELL ratios and temperature. When all Mg/CaSHELL data were compared to temperature, a weak but statistically significant correlation was observed (r2 = 0.05, p < 0.01). Because date assignments may become increasingly uncertain further back in time and earlier studies identified ontogenetic effects in juvenile portions of shells from other bivalve species, we examined the relationship from only the last year of growth. When only data from the last year of growth were compared, a slightly stronger positive relationship between Mg/CaSHELL ratios andDMg (the partition coefficient) emerged (Mg/CaSHELL, r2 = 0.30, p < 0.01; DMg, r2 = 0.33, p < 0.01). The improved correlation may result from either ontogenetic effects influencing the incorporation of Mg into the younger portion of the shell and/or inaccurate date assignments. Regardless of the cause, our equations are similar to previously published equations for C. virginica and other taxa. Despite the low correlations, our improved relationship supports further study under controlled experimental conditions.
Numerical modeling of the fluid flow impact of thin baffle laminae in cross bedding
Authors: Ma Jingsheng , Couples Gary D. , Gardiner Andy R.
Published: April 2008

Thin layers of less permeable materials can occur in cross‐bedded rocks and may function as flow baffles, thus influencing the bulk fluid flow. However, it can be challenging to model their flow impact using standard grid‐based techniques that can only capture the topology and geometry of the layers accurately using a large number of small cells. In this paper, a numerical method, recently developed by the authors for modeling fluid flow in fault damage zones that contain thin low‐permeability fault strands, is demonstrated as being applicable to modeling the flow impact of thin baffle laminae in cross beds. This method does not require thin baffles to be discretized explicitly. For a range of permeability contrasts between the thin baffle layers and the rest of the matrix, upscaled permeability values are derived for models that have the same volumetric fraction of baffle material. The results show that when the baffles are completely connected, the upscaled permeability is less than for cases where the baffles do not form a continuous impediment for all levels of permeability contrast and declines more steeply with the increase of the permeability contrast. The flow effect of the layer configuration becomes more apparent for the disconnected situation when the permeability contrast is high. The method is shown to be accurate and efficient for this type of work. These results highlight the importance of capturing the topology and volume of the thin baffle layers in flow modeling of cross beds and the necessity of using appropriate numerical techniques.
In Memoriam
Authors: Anonymous
Published: April 2008

John E. Brolley, 89, 28 January 2008, Magnetospheric Physics, 1980

Steven Clifford, 64, 18 September 2007, Atmospheric Sciences, 1974
Understanding Marine Biotic Responses to Fossil Fuel Emissions: ESF EuroCLIMATE Workshop: Atmospheric CO2, Ocean Acidification, and Ecological Changes in Planktonic Calcifying Organisms; Barcelona, Spain, 26–28 September 2007
Authors: Ziveri Patrizia , Young Jeremy , Fabry Victoria , Bijma Jelle , Turk Daniela , Kiefer Thorsten , Eisenhauer Tony
Published: April 2008

Ocean acidification (OA) is increasingly recognized as an additional effect of rising carbon dioxide (CO2) levels. To study this, a workshop, funded by the European Science Foundation EuroCLIMATE Programme and the Past Global Changes (PAGES) project, brought together a range of experts to review knowledge of the likely effects of OA on planktonic calcifying organisms and marine biogeochemistry in the upper ocean and to prioritize research for the near future.

The 45 participants reviewed research on four core‐topic sessions: (1) Biocalcification mechanisms and their vulnerability to OA; (2) Genetics and physiology: Investigating organismal responses to OA; (3) Ecology and biogeography: Predicting the effects of population responses to OA; and (4) Lessons from the fossil record: Past responses to OA. Results and discussion will be published; a detailed report is available at http://www.esf.org/acidification‐workshop/venue.html and http://the‐eggs.org/articles.php?id=112.
Demonstrating fractal scaling of baseflow residence time distributions using a fully‐coupled groundwater and land surface model
Authors: Kollet Stefan J. , Maxwell Reed M.
Published: April 2008

The influence of the vadose zone, land surface processes, and macrodispersion on the shape and scaling behavior of residence time distributions of baseflow is studied using a fully coupled watershed model in conjunction with a Lagrangian, particle‐tracking approach. Numerical experiments are used to simulate groundwater flow paths from recharge locations along the hillslope to the streambed. These experiments are designed to isolate the influences of topography, vadose zone/land surface processes, and macrodispersion on subsurface transport of tagged parcels of water. The results of these simulations agree with previous observations that such distributions exhibit a power law form and fractal behavior, which can be identified from plots of the residence time distribution and the power spectra. It is shown that vadose zone/land surface processes significantly affect both the residence time distributions and their spectra.
Evidence of impacts from rising temperature on inflows to the Murray‐Darling Basin
Authors: Cai Wenju , Cowan Tim
Published: April 2008

The 2001–2007 Australian drought was the hottest on record with inflows to Australia's longest river system, the Murray‐Darling, reaching an historical low. Here we examine the relative importance of rising temperature and decreasing rainfall over its catchment, the Murray Darling Basin (MDB). Although annual‐total inflow is more sensitive to rainfall over the southern MDB, where rainfall since 2001, has been the lowest on record, this alone can not explain the observed inflow decline. A relationship exists between inflow variations and fluctuations of temperature not associated with rainfall in the austral winter and spring: a rise of 1°C leads to an approximate 15% reduction in the climatological annual inflow. Our results provide strong evidence that rising temperatures due to the enhanced greenhouse effect have a strong impact on southern Australia's water resources, in addition to any reduction in rainfall, and project a long‐term decline in inflows to this river system as the greenhouse effect continues.
The autoimmune regulator PHD finger binds to non‐methylated histone H3K4 to activate gene expression
Authors: Org Tõnis , Chignola Francesca , Hetényi Csaba , Gaetani Massimiliano , Rebane Ana , Liiv Ingrid , Maran Uko , Mollica Luca , Bottomley Matthew J , Musco Giovanna , Peterson Pärt
Published: April 2008

Mutations in the gene autoimmune regulator (AIRE) cause autoimmune polyendocrinopathy candidiasis ectodermal dystrophy. AIRE is expressed in thymic medullary epithelial cells, where it promotes the expression of tissue‐restricted antigens. By the combined use of biochemical and biophysical methods, we show that AIRE selectively interacts with histone H3 through its first plant homeodomain (PHD) finger (AIRE–PHD1) and preferentially binds to non‐methylated H3K4 (H3K4me0). Accordingly, in vivo AIRE binds to and activates promoters containing low levels of H3K4me3 in human embryonic kidney 293 cells. We conclude that AIRE–PHD1 is an important member of a newly identified class of PHD fingers that specifically recognize H3K4me0, thus providing a new link between the status of histone modifications and the regulation of tissue‐restricted antigen expression in thymus.
The role of kinases in the Hedgehog signalling pathway
Authors: Aikin Reid A , Ayers Katie L , Thérond Pascal P
Published: April 2008

The Hedgehog (Hh) signalling pathway has a crucial role in several developmental processes and is aberrantly activated in a variety of cancers. In Drosophila, many of the canonical Hh pathway components are phosphorylated, yet the precise role of these phosphorylation events in the regulation of Hh signal transduction is unclear. Furthermore, the Hh pathway receives input from several kinases that have well‐described roles in other cellular functions, some of which have both positive and negative effects on Hh signalling. Several recent studies have characterized the role of specific phosphorylation events in the Hh pathway, and have begun to shed light on how phosphorylation of Hh signalling components affects their subcellular location, stability and activity to mediate the transcriptional response to the Hh gradient.
Review of the Carbon Dioxide Splitting Patent Literature
Authors: Rayne Sierra
Published: April 2008

Increasing concentrations of carbon dioxide in the atmosphere have stimulated significant global research and development efforts regarding the reduction in emissions from all point and non-point sources. In addition to technologies that do not use carbon feedstocks or which capture and "permanently" store carbon dioxide (i.e., sequestration), there is considerable worldwide interest for dissociating waste stream carbon dioxide molecules into their constituent carbon and oxygen atoms ("CO2 splitting") as a final "end-of-pipe" treatment option. This document presents a review of on-point issued and applied for patents in the field of carbon dioxide splitting. The findings suggest patents in this area appear to be subject to a higher standard because of the global importance of the carbon dioxide issue. Authorities may be hesitant, on policy grounds, to issue broad-ranging patents for carbon dioxide splitting in order to prevent a worldwide reluctance towards adopting feasible treatment methods because of the high patent licensing costs that may accrue.
A silica long base tiltmeter with high stability and resolution
Authors: Boudin F. , Bernard P. , Longuevergne L. , Florsch N. , Larmat C. , Courteille C. , Blum P.-A. , Vincent T. , Kammentaler M.
Published: April 2008

In order to be able to provide valuable data in multiparameter measurement field operations, tiltmeters need to have a noise level better or equal than 10−9rad for a period range from a few minutes to a few years and a long term stability ranging from 10−7to10−8rad∕yr. Tiltmeter measurements should also be as much as possible insensitive to thermal disturbances, by taking great care of the horizontality of the base line tube first. Secondly, thermal responses have been assessed. We also took great care of the coupling of our tiltmeters with the bedrock. We’ve designed a long base tiltmeter with sensors in silica which has a low dilatation coefficient. The linear variable displacement transducer is based on coil coupling (powered by an alternative voltage). Finally we show the results of two 100m silica water tube tiltmeters which were installed in a mine in the French Vosges massif in the framework of a hydrology research project. These instruments show a remarkably good stability (6.5×10−9rad∕month) and a low noise level (of the order of 10−11rad). Toroidal and spheroidal free modes of the Earth were observed after the two last major earthquakes on Sumatra.
Theoretical study of the interaction of carbon monoxide with 3d metal dimers
Authors: Jiang Ling , Xu Qiang
Published: April 2008

The interaction of carbon monoxide with 3d metal dimers (scandium through zinc) has been examined using six different exchange-correlation density functionals. Results are compared to the relevant experimental values and to other theoretical investigations when available, and the overall agreement has been obtained. The BP86 functional gives calculated C–O stretching vibrational frequencies much closer to the experimental values than the B3P86, B3LYP, mPW1PW91, and PBE1PBE functionals, and furthermore, replacing the correlation part by the Lee–Yang–Parr correlation functional yields essentially the same results. It is generally found that on going from left to right across the 3d metal series, the preference for geometrical configuration is from side-on-bonded mode to bridging, and then to terminal, whereas Ni2CO adopts bridging mode. Particularly, the present computation reveals a significant tendency toward four-electron donor carbonyl groups with metal-oxygen bonds with the early transition metals scandium and titanium. The C–O stretching vibrational frequencies in the ground states of M2CO (M=Sc to Zn) increase generally from the left to the right side of the Periodic Table. The binding energies exhibit an overall decrease trend. These general trends in the interaction of carbon monoxide with 3d metal dimers mirror the main features of CO adsorption on transition metal surfaces.
A new potential energy surface and predicted infrared spectra of He–CO2: Dependence on the antisymmetric stretch of CO2
Authors: Ran Hong , Xie Daiqian
Published: April 2008

A new potential energy surface involving the antisymmetric Q3 normal mode of CO2 for the He–CO2 van der Waals complex is constructed at the coupled-cluster singles and doubles with noniterative inclusion of connected triple [CCSD(T)] level with augmented correlation-consistent quadruple-zeta (aug-cc-pVQZ) basis set plus bond functions. Two vibrationally adiabatic potentials with CO2 at both the ground and the first excited vibrational states are generated from the integration of the three-dimensional potential over the Q3 coordinate. The potential has a T-shaped global minimum and two equivalent linear local minima. The bound rovibrational energy levels are obtained using the radial discrete variable representation/angular finite basis representation method and the Lanczos algorithm. The observed band origin shift of the complex (0.0946cm−1) is successfully reproduced by our calculation (0.1034cm−1). The infrared spectra of the complex are also predicted. The fundamental band is in excellent agreement with the experiment. Most of the transitions corresponding to the observed hot band [M. J. Weida et al., J. Chem. Phys. 101, 8351 (1994)] are assigned reasonably.
Improvement of the coupled-cluster singles and doubles method via scaling same- and opposite-spin components of the double excitation correlation energy
Authors: Takatani Tait , Hohenstein Edward G. , Sherrill C. David
Published: April 2008

There has been much interest in cost-free improvements to second-order Møller–Plesset perturbation theory (MP2) via scaling the same- and opposite-spin components of the correlation energy (spin-component scaled MP2). By scaling the same- and opposite-spin components of the double excitation correlation energy from the coupled-cluster of single and double excitations (CCSD) method, similar improvements can be achieved. Optimized for a set of 48 reaction energies, scaling factors were determined to be 1.13 and 1.27 for the same- and opposite-spin components, respectively. Preliminary results suggest that the spin-component scaled CCSD (SCS-CCSD) method will outperform all MP2 type methods considered for describing intermolecular interactions. Potential energy curves computed with the SCS-CCSD method for the sandwich benzene dimer and methane dimer reproduce the benchmark CCSD(T) potential curves with errors of only a few hundredths of 1kcalmol−1 for the minima. The performance of the SCS-CCSD method suggests that it is a reliable, lower cost alternative to the CCSD(T) method.
Experiments on three-dimensional wall-layer scale Lorentz actuators in high-Reynolds-number axisymmetric turbulent boundary layers
Authors: Bandyopadhyay P. R. , Castano J. M. , Thivierge D. P.
Published: April 2008

Drag reduction of high-Reynolds-number axisymmetric bodies in saltwater flow using numerous small Lorentz actuators is considered. The actuators are three-dimensional and each of them encompasses the footprint of approximately one turbulence production domain at a Reynolds number Reτ of 103, based on friction velocity and boundary layer thickness. The actuators seed the turbulent boundary layer locally with pulsing toroids of vorticity that straddle the periphery of the actuators. The central downward jet of the toroid counters the upward flow between naturally occurring near-wall vortex pairs. Owing to the presence of the wall, the downward central jet is deflected into wall-jets that lie underneath the toroid. The agglomerated effects of the pulsing of the power applied to the three-dimensional actuators are modeled as Stokes oscillators. An axisymmetric body containing 210 numbers of subcentimeter-scale electromagnetic surface actuators was built. Measurements over this body show that drag reduction efficiency is higher compared to that expected in two-dimensional actuators at similar Reynolds numbers. Drag reduction depends on the parameter StT+∕(2πReτn), where St is Stuart number and T+ is pulsing time scale in wall-layer variables, approximately in the same manner as two-dimensional actuators do. However, the exponent n is zero—not 1.0 like that in two-dimensional actuators. At Reτ≫103, the same three-dimensional actuators would no longer match the footprints of the unit turbulence production domains and the same applied power would be a weaker perturbation on the streak vorticity. A denser clustering of three-dimensional actuators for the same input power is a likely solution for higher Reynolds numbers.
Redistribution of dopant during microwave annealing of a multilayer structure for production p−n junction
Authors: Pankratov E. L.
Published: April 2008

In this paper analysis of dopant redistribution in a multilayer structure during microwave annealing for production of p−n junctions has been done. It has been shown that inhomogeneity of the solid-state structure leads to increasing sharpness of the p−n junction and the homogeneity of dopant distribution in doped areas. Inhomogeneity of temperature distribution in the multilayer structure (the inhomogeneity corresponds to microwave annealing), which leads to increasing sharpness of the p−n junction and the homogeneity of dopant distribution, has been studied. Some conditions on properties of the considered multilayer structure, which correspond to increasing sharpness and homogeneity, have been determined.
Calculation of the gas temperature in a throughflow atmospheric pressure dielectric barrier discharge torch by spectral line shape analysis
Authors: Ionascut-Nedelcescu A. , Carlone C. , Kogelschatz U. , Gravelle D. V. , Boulos M. I
Published: April 2008

An analysis of spectral line profiles is used to calculate the gas temperature and to estimate the upper limit of the electron density in an atmospheric pressure dielectric barrier discharge torch. Two transitions are studied, that of helium (He) at 587.5nm and that of hydrogen (Hβ) at 486.1nm, both observed in the spectra of the light emitted from the gap-space region. Relevant broadening mechanisms including the Doppler and Stark effects, as well as the collision processes between an emitter and a neutral particle, are reviewed. It is deduced that the main contribution to the broadened profiles is due to collisions. Through knowledge of the van der Waals interaction potential, a general expression for determining the gas temperature is derived and applied to each transition. The results obtained from both lines are in agreement; i.e., the gas temperature is found to be 460±60K at the highest voltage applied. This value is consistent with the experimental observation that at these conditions the afterglow plasma cannot ignite paper, whose ignition temperature is 507K. Since no signature of the Stark effect can be detected either in He or Hβ transition, the upper limit of the electron density, estimated from the uncertainty on the Hβ linewidth, is 4×1012cm−3. The generality of the method allows one to determine the temperature as a function of other parameters, such as voltage and flow rate. Concerning the applied voltage, the gas temperature increases linearly from 315±30to460±60K, as derived from both lines. Over the same voltage range, a similar behavior is found for the rotational temperature, as deduced from the first negative B(Σu+2,v=0)→X(Σg+2,v=0) transition of the molecular nitrogen ion. However, the temperature varies between 325±30 and 533±15K, indicating an overestimation of the gas temperature. On the other hand, the gas temperature derived from each of the lines does not show a significant variation with the He flow rate in the range of 5–40l∕min.
Characterization of majority and minority carrier deep levels in p-type GaN:Mg grown by molecular beam epitaxy using deep level optical spectroscopy
Authors: Armstrong A. , Caudill J. , Corrion A. , Poblenz C. , Mishra U. K. , Speck J. S. , Ringel S. A.
Published: April 2008

Deep level defects in p-type GaN:Mg grown by molecular beam epitaxy were characterized using steady-state photocapacitance and deep level optical spectroscopy (DLOS). Low frequency capacitance measurements were used to alleviate dispersion effects stemming from the deep Mg acceptor. Use of DLOS enabled a quantitative survey of both deep acceptor and deep donor levels, the latter being particularly important due to the limited understanding of minority carrier states for p-type GaN. Simultaneous electron and hole photoemissions resulted in a convoluted deep level spectrum that was decoupled by emphasizing either majority or minority carrier optical emission through control of the thermal filling time conditions. In this manner, DLOS was able to resolve and quantify the properties of deep levels residing near both the conduction and valence bandedges in the same sample. Bandgap states through hole photoemission were observed at Ev+3.05eV, Ev+3.22eV and Ev+3.26eV. Additionally, DLOS revealed levels at Ec−3.24eV and Ec−2.97eV through electron emission to the conduction band with the former attributed to the Mg acceptor itself. The detected deep donor concentration is less than 2% of activated [Mg] and demonstrates the excellent quality of the film.
Compressible streaming instabilities of warm multicomponent collisional magnetized astrophysical disks
Authors: Nekrasov A. K.
Published: April 2008

A general theory for instabilities of multicomponent warm magnetized accretion disks is developed using Maxwell’s equations and the equations of motion and continuity for each disk component. The compressibility, anisotropic thermal pressure, and collisions of the charged species with neutrals are taken into account. The thermal effects are involved without any simplifications. An equilibrium state is discussed. The dispersion relation is derived in the most general form for an arbitrary direction of the wave vector of perturbations and for an arbitrary strength of the thermal effects. The solutions of the dispersion relation are found in some specific case appropriated for the weakly ionized plasma in the regions of the protostellar and protoplanetary disks, where the electrons can be considered as thermal and magnetized and the ions and dust grains as cold and unmagnetized. These solutions describe new axisymmetric and nonaxisymmetric electromagnetic disk instabilities due to collisions and the difference between the stationary azimuthal velocities of different charged species.
Vacuum-UV negative photoion spectroscopy of SF5CF3
Authors: Simpson M. J. , Tuckett R. P. , Dunn K. F. , Hunniford C. A. , Latimer C. J. , Scully S. W. J.
Published: April 2008

Ion pair formation, generically described as AB→A++B−, from vacuum-UV photoexcitation of trifluoromethyl sulfur pentafluoride, SF5CF3, has been studied by anion mass spectrometry using synchrotron radiation in the photon energy range of 10–35eV. The anions F−, F2−, and SFx− (x=1–5) are observed. With the exception of SF5−, the anions observed show a linear dependence of signal with pressure, showing that they arise from ion pair formation. SF5− arises from dissociative electron attachment, following photoionization of SF5CF3 as the source of low-energy electrons. Cross sections for anion production are put on to an absolute scale by calibration of the signal strengths with those of F− from both SF6 and CF4. Quantum yields for anion production from SF5CF3, spanning the range of 10−7–10−4, are obtained using vacuum-UV absorption cross sections. Unlike SF6 and CF4, the quantum yield for F− production from SF5CF3 increases above the onset of photoionization.
Transmission properties of electron in quantum rings
Authors: Li Chun-Lei , Yang Fu-Hua , Feng Song-Lin , Wang Xiao-Ming
Published: April 2008

We investigated the transmission probability of a single electron transmission through a quantum ring device based on the single-band effective mass approximation method and transfer matrix theory. The time-dependent Schrödinger equation is applied on a Gaussian wave packet passing through the quantum ring system. The electron tunneling resonance peaks split when the electron transmits through a double quantum ring. The splitting energy increases as the distance between the two quantum rings decreases. We studied the tunneling time through the single electron transmission quantum ring from the temporal evolution of the Gaussian wave packet. The electron probability density is sensitive to the thickness of the barrier between the two quantum rings.
A novel antiproton radial diagnostic based on octupole induced ballistic loss
Authors: Andresen G. B. , Bertsche W. , Bowe P. D. , Bray C. C. , Butler E. , Cesar C. L. , Chapman S. , Charlton M. , Fajans J. , Fujiwara M. C. , Funakoshi R. , Gill D. R. , Hangst J. S. , Hardy W. N. , Hayano R. S. , Hayden M. E. , Humphries A. J. , Hydomako R. , Jenkins M. J. , Jørgensen L. V. , Kurchaninov L. , Lambo R. , Madsen N. , Nolan P. , Olchanski K. , Olin A. , Page R. D. , Povilus A. , Pusa P. , Robicheaux F. , Sarid E. , El Nasr S. Seif , Silveira D. M. , Storey J. W. , Thompson R. I. , van der Werf D. P. , Wurtele J. S. , Yamazaki Y.
Published: April 2008

We report results from a novel diagnostic that probes the outer radial profile of trapped antiproton clouds. The diagnostic allows us to determine the profile by monitoring the time history of antiproton losses that occur as an octupole field in the antiproton confinement region is increased. We show several examples of how this diagnostic helps us to understand the radial dynamics of antiprotons in normal and nested Penning–Malmberg traps. Better understanding of these dynamics may aid current attempts to trap antihydrogen atoms.
Experimental and theoretical correlation of very intense visible green photoluminescence in BaZrO3 powders
Authors: Cavalcante L. S. , Longo V. M. , Zampieri M. , Espinosa J. W. M. , Pizani P. S. , Sambrano J. R. , Varela J. A. , Longo E. , Simões M. L. , Paskocimas C. A.
Published: April 2008

Very intense visible green photoluminescence (PL) was observed at room temperature in structurally ordered-disordered BaZrO3 powders. Ab initio calculations, ultraviolet-visible absorption spectroscopy, electron paramagnetic resonance, and PL were performed. Theoretical and experimental results showed that local defects in the cubic structure caused by [ZrO5⋅VOz] complex clusters, where VOz=VOx, VO•, and VO••, play an important role in the formation of hole-electron pairs, giving rise to a charge gradient in the structure which is responsible for PL emission.