bluuebunny/crossref_metadata_2025 huggingface dataset:
Job strain, work characteristics and back pain: A study in a University hospital
Authors: Courvoisierl Delphine S. , Genevayl Stéphane , Cedraschil Christine , Bessirel Nadia , Griesser‐Delacretazl Anne‐Claude , Monninl Dominique , Pernegerl Thomas V.
Published: December 2010

Objectives: The demand‐control‐support “job strain” model is frequently used in occupational health research. We sought to explore the relationship between job strain and back pain.

Method: One thousand two hundred and ninety‐eight collaborators of a Swiss teaching hospital responded to a cross‐sectional questionnaire survey that measured job strain, the occurrence of back pain as well as the characteristics and consequences of this pain.

Results: Job strain computed with both psychological and physical demands was strongly and significantly associated with various measures of back pain. These associations displayed a dose—response pattern, and remained strong even after adjustment for job characteristics and professional categories. In contrast, separate dimensions of job strain (except physical demands) and job strain computed with only psychological demands did not remain significantly associated with back pain after adjustment for other variables.

Conclusion: Our results support the findings linking back pain to job strain. Moreover, the relationship between back pain and job strain is much stronger if job strain includes both psychological and physical demands. Results of this study suggest that workplace interventions that aim to reduce job strain may help prevent back pain and may alleviate the personal, social, and economic burden attributable to back pain.
Comparison of digital and optical hand-held refractometers for the measurement of feline urine specific gravity
Authors: Bennett Alexander D. , McKnight Grace E. , Dodkin Steve J. , Simpson Kerry E. , Schwartz Anita M. , Gunn-Moore Danièlle A.
Published: December 2010

Measuring urine specific gravity (USG) is an important component of urine analysis as it evaluates renal concentrating capability. The objective of this study was to quantify the difference in USG values between a hand-held optical analogue refractometer and a cat-specific digital instrument. Urine samples from 55 cats were assessed. There was a statistically significant difference between these two refractometers ( P<0.001), with the optical refractometer (mean USG=1.031) consistently reading higher than the digital refractometer (mean USG=1.027). Results for a random subset of the samples ( n=10) were compared with urine osmolality and both the optical and digital instruments demonstrated excellent correlation. While an accurate USG reading is important, it is unlikely that the statistical significance between the two instruments is clinically significant and, therefore, unlikely to result in a change in patient evaluation or treatment plans. While both the digital and optimal refractometers are highly correlated to the urine osmolality, making both devices valid for assessment of USG in clinical practice, this digital device is easier to read and eliminates the variability of subjective interpretation.
Retrobulbar thrombus in a cat with systemic hypertension
Authors: Norsworthy Gary D. , de Faria Vanessa P.
Published: December 2010

This report describes a 14-year-old neutered male Norwegian Forest cat that was evaluated for a complaint of inappetence, lethargy, and ocular protrusion with third eyelid prolapse. The systemic blood pressure was elevated at 205/129 mmHg. Fundic examination revealed severe retinal hemorrhage in both eyes. Based on an ultrasound study of the retrobulbar area, a thrombus caudal to the right globe was suspected. Over 18 days, the cat exhibited significant clinical improvement as well as good blood pressure control. To our knowledge this is the first report of a retrobulbar thrombus in a cat with systemic hypertension.
Field research in operations and supply chain management
Authors: DeHoratius Nicole , Rabinovich Elliot
Published: December 2010

This article highlights the contribution of field research to the generation of operations and supply chain management theory. We summarize the papers included in this special issue while emphasizing the value of research that offers rich descriptions of operating practices. The specific articles included in this volume illustrate how field based observations and a deep understanding of the operating phenomenon can benefit both the development of theory and the advancement of management practice.
Taxonomic status and paleoecology of Rusingoryx atopocranion (Mammalia, Artiodactyla), an extinct Pleistocene bovid from Rusinga Island, Kenya
Authors: Faith J. Tyler , Choiniere Jonah N. , Tryon Christian A. , Peppe Daniel J. , Fox David L.
Published: December 2010

Rusingoryx atopocranion is a poorly known extinct alcelaphine bovid, documented in Pleistocene deposits associated with Middle Stone Age artifacts on Rusinga Island, Kenya. Following its initial description, Rusingoryx was subsumed into Megalotragus, which includes the extinct giant wildebeests, on the basis of its cranial architecture. Renewed investigations of the Pleistocene deposits on Rusinga Island recovered a large sample of Rusingoryx specimens that provide new taxonomic and paleoecological insight. This study (1) reviews the morphological and phylogenetic evidence concerning the taxonomic status of Rusingoryx and (2) evaluates its paleoecology and dietary habits. The morphology and phylogenetic data indicate that Rusingoryx is distinct from Megalotragus; they likely shared a common ancestor in the late Pliocene. Ecomorphology and mesowear analysis point to a specialized grazing adaptation, and its association with arid-adapted ungulates suggests a preference for arid grasslands. The confirmation of Rusingoryx as a valid taxonomic entity, together with the presence of other extinct taxa (including Megalotragus) on Rusinga Island, suggests an increasingly complex pattern of ungulate biogeography and extinctions in the late Quaternary of East Africa. Rusingoryx appears to have been part of an arid-adapted faunal community that potentially persisted in East Africa until the onset of the Holocene.
A chironomid-based reconstruction of summer temperatures in NW Iceland since AD 1650
Authors: Langdon P.G. , Caseldine C.J. , Croudace I.W. , Jarvis S. , Wastegård S. , Crowford T.C.
Published: December 2010

Few studies currently exist that aim to validate a proxy chironomid-temperature reconstruction with instrumental temperature measurements. We used a reconstruction from a chironomid percentage abundance data set to produce quantitative summer temperature estimates since AD 1650 for NW Iceland through a transfer function approach, and validated the record against instrumental temperature measurements from Stykkishólmur in western Iceland. The core was dated through Pb-210, Cs-137 and tephra analyses (Hekla 1693) which produced a well-constrained dating model across the whole study period. Little catchment disturbance, as shown through geochemical (Itrax) and loss-on-ignition data, throughout the period further reinforce the premise that the chironomids were responding to temperature and not other catchment or within-lake variables. Particularly cold phases were identified between AD 1683–1710, AD 1765–1780 and AD 1890–1917, with relative drops in summer temperatures in the order of 1.5–2°C. The timing of these cold phases agree well with other evidence of cooler temperatures, notably increased extent of Little Ice Age (LIA) glaciers. Our evidence suggests that the magnitude of summer temperature cooling (1.5–2°C) was enough to force LIA Icelandic glaciers into their maximum Holocene extent, which is in accordance with previous modelling experiments for an Icelandic ice cap (Langjökull).
Intraoperative Neuromonitoring for Early Localization and Identification of Recurrent Laryngeal Nerve During Thyroid Surgery
Authors: Chiang Feng‐Yu , Lu I‐Cheng , Chen Hui‐Chun , Chen Hsiu‐Ya , Tsai Cheng‐Jing , Lee Ka‐Wo , Hsiao Pi‐Jung , Wu Che‐Wei
Published: December 2010

Early and definite identification of the recurrent laryngeal nerve (RLN) is an important step to avoid inadvertent nerve injury during complicated thyroid operations. This study aimed to determine the feasibility of routine use of intraoperative neuromonitoring (IONM) to localize and identify the RLN at an early stage of thyroid surgery. This prospective study enrolled 220 consecutive patients (333 RLNs at risk) who underwent thyroid operations with application of IONM. The RLN was localized and identified routinely with a nerve stimulator after opening the space between the thyroid and carotid sheath. The success rates of early RLN localization and identification were evaluated. The current for localization and the amplitude of evoked laryngeal electromyographic signals were also recorded and analyzed. All RLNs, including 87 (26%) nerves that were regarded as difficult to identify, were successfully localized and identified. The stimulation level for RLN localization was 2mA in 315 nerves (95%) and 3mA in the other 18 nerves (5%). The signal obtained from RLN localization (amplitude = 932 ±436μV) showed a clear and reliable laryngeal electromyographic response that was similar to that from direct vagus (amplitude=811±389μV) or RLN stimulation (amplitude=1132±472μV). The palsy rate was 0.6% and no permanent palsy occurred. RLN injury is rare if the nerve is definitely identified early in the thyroid operation. The conclusion of this study is that IONM is a reliable tool for early RLN localization and identification, even in complicated thyroid operations.
Electromyographic Study of Differential Sensitivity to Succinylcholine of the Diaphragm, Laryngeal and Somatic Muscles: A Swine Model
Authors: Lu I‐Cheng , Wang Hsun‐Mo , Kuo Yi‐Wei , Shieh Chia‐Fang , Chiang Feng‐Yu , Wu Che‐Wei , Tsai Cheng‐Jing
Published: December 2010

Neuromuscular blocking agents (NMBAs) might diminish the electromyography signal of the vocalis muscles during intraoperative neuromonitoring of the recurrent laryngeal nerve. The aim of this study was to compare differential sensitivity of different muscles to succinylcholine in a swine model, and to realize the influence of NMBAs on neuromonitoring. Six male Duroc‐Landrace piglets were anesthetized with thiamylal and underwent tracheal intubation without the use of an NMBA. The left recurrent laryngeal nerve, the spinal accessory nerve, the right phrenic nerve and the brachial plexus were stimulated. Evoked potentials (electromyography signal) of four muscle groups were elicited from needle electrodes before and after intravenous succinylcholine bolus (1.0 mg/kg). Recorded muscles included the vocalis muscles, trapezius muscle, diaphragm and triceps brachii muscles. The onset time and 80% recovery of control response were recorded and analyzed. The testing was repeated after 30 minutes. The onset time of neuromuscular blocking for the vocalis muscles, trapezius muscle, diaphragm and triceps brachii muscle was 36.3 ± 6.3 seconds, 38.8 ± 14.9 seconds, 52.5 ± 9.7 seconds and 45.0 ± 8.2 seconds during the first test; and 49.3 ± 10.8 seconds, 40.0 ± 12.2 seconds, 47.5 ± 11.9 seconds and 41.3 ± 10.1 seconds during the second test. The 80% recovery of the control response for each muscle was 18.3 ± 2.7 minutes, 16.5±6.9 minutes, 8.1±2.5 minutes and 14.8±2.9 minutes during the first test; and 21.5±3.8 minutes, 12.5 ± 4.3 minutes, 10.5 ± 3.1 minutes and 16.4 ± 4.2 minutes during the second test. The sensitivity of the muscles to succinylcholine, ranked in order, was: the vocalis muscles, the triceps brachii muscle, the trapezius muscle and the diaphragm. We demonstrated a useful and reliable animal model to investigate the effects of NMBAs on intraoperative neuromonitoring. Extrapolation of these data to humans should be done with caution.
Immigration Distress and Associated Factors Among Vietnamese Women in Transnational Marriages in Taiwan
Authors: Yang Yung‐Mei , Wang Hsiu‐Hung , Anderson Debra
Published: December 2010

The purpose of this study was to explore the types and predictors of immigration distress among Vietnamese women in transnational marriages in Taiwan. A cross‐sectional survey with face‐to‐face interviews was conducted for data collection. A convenient sample of 203 Vietnamese women in transnational marriages in southern Taiwan was recruited. The Demographic Inventory measured the participants' age, education, employment status, religion, length of residency and number of children, as well as their spouse's age, education, employment status and religion. The Demand of Immigration Specific Distress scale measured the level of distress and had six subscales: loss, novelty, occupational adjustment, language accommodation, discrimination and alienation. Among the 203 participants, 6.4% had a high level of immigration distress; 91.1% had moderate distress; and 2.5% had minor distress. Higher mean scores were found for the loss, novelty and language accommodation subscales of the Demand of Immigration Specific Distress scale. Participant's (r = 0.321, p < 0.01) and spouse's (r = 0.375, p < 0.01) unemployment, and more children (r = 0.129, p < 0.05) led to greater immigration distress. Length of residency in Taiwan (r = 0.576, p < 0.001) was an effective predictor of immigration distress. It indicated that the participants who had stayed fewer years in Taiwan had a higher level of immigrant distress. Health care professionals need to be aware that the female newcomers in transnational marriages are highly susceptible to immigration distress. The study suggests that healthcare professionals need to provide a comprehensive assessment of immigration distress to detect health problems early and administer culturally appropriate healthcare for immigrant women in transnational marriages.
Anorectal Malignant Melanomas: Experience of Uludag University
Authors: Aytac Berna , Adim Saduman Balaban , Yerci Omer , Yilmazlar Tuncay
Published: December 2010

Anorectal melanomas represent a group of mucosal melanomas with unknown etiology and poor prognosis. The lesions can be misdiagnosed as hemorrhoids during clinical examination. We reviewed the morphological and clinical features of 14 anorectal melanomas, and discuss the treatment modalities of this entity. Fourteen patients who were diagnosed with anorectal malignant melanoma between 1997 and 2004 were evaluated with regard to age, sex, size, morphology, lymph node or distant metastasis, treatment modality and survival. Eight patients were female and six were male, and their mean age was 58 years. The size of melanoma ranged from 3 cm to 8 cm. Pathological evaluation revealed epithelioid and spindle cell type tumor in seven and two patients, respectively, whereas, in the remaining seven patients, the tumor was composed of both types. Pigmentation was apparent in all tumors. There was lymph node metastasis in 11 patients and distant metastasis in all patients. Eleven patients underwent abdominoperineal resection and three were treated by local excision. Mean survival was 8.7 months. Prognosis of anorectal melanoma remains poor. Awareness of the diverse clinicopathological features of these lesions, both on the part of the clinicians and pathologists, is crucial for their early detection and proper treatment.
Multiple Organ Infarctions Following Disseminated Intravascular Coagulation Precipitated by Sepsis in A Healthy Infant: A Case Report
Authors: Wang Chien‐Hua , Lee Min‐Sheng , Lin Lung‐Chang , Yang Rei‐Cheng
Published: December 2010

Multiple organ infarctions are a very rare clinical event in children. We report a 3‐month‐old infant with sepsis and disseminated intravascular coagulation, who was diagnosed with cerebral ischemic stroke associated with middle cerebral artery stenosis and subsequent retinal infarction by magnetic resonance imaging, fundoscopy and magnetic resonance angiography. In addition, he suffered from renal infarction with hypertension and was treated until 1 year of age. We emphasize the importance of early recognition of organ infarctions, prophylaxis of risk factors and of optimized therapy of the underlying etiology.
Subcutaneous Emphysema, Pneumothorax, Pneumomediastinum, and Pneumoperitoneum During Colonoscopic Balloon Dilation: A Case Report
Authors: Chan Yi‐Chen , Tsai Yu‐Chuan , Fang Shih‐Yuan
Published: December 2010

A 77‐year‐old woman underwent colonoscopic balloon dilatation for colonic stricture 1 year after laparoscopic anterior resection of sigmoid colon cancer. During the balloon dilatation, panfacial swelling and apnea were noted. Emergency endotracheal intubation was undertaken. Chest X‐ray revealed diffuse subcutaneous emphysema and bilateral pneumothorax. We discuss the possible mechanism and management of this uncommon complication during therapeutic colonoscopy.
Malignant Melanoma of the Choroid in the Eye With Oculodermal Melanocytosis of a Chinese Woman
Authors: Chen Ya‐Chi , Chang Cheng‐Hsien , Hsu Shiuh‐Liang , Hsu Min‐Wen , Lee Chia‐Ling
Published: December 2010

In this study, we report a rare case of choroidal melanoma in an eye with oculodermal melanocytosis (Nevus of Ota). A 56‐year‐old Taiwanese woman with oculodermal melanocytosis in the right eye was found to have an ipsilateral uveal melanoma. Histopathology of the enucleated eye confirmed the diagnosis of malignant choroidal melanoma of mixed cell type. A search of the literature revealed strong evidence that oculodermal melanocytosis can predispose to the development of uveal melanoma in Caucasians. Only seven such cases have been reported in the East Asian population. This is believed to be the first such reported case in a patient of Chinese descent.
Spontaneous Internal Jugular Vein Thrombosis: A Case Report
Authors: Serinken Mustafa , Karcioglu Ozgur , Korkmaz Ayhan
Published: December 2010

Internal jugular vein thrombosis (IJVT) is an elusive vascular disease that is rarely seen, with potentially lethal complications such as sepsis and pulmonary embolism. Spontaneous IJVT is considered when no apparent predisposing cause of thrombosis is present. A previously healthy, 31‐year‐old woman presented to the university‐based emergency department because of painless swelling in the right anterior side of her neck. Physical examination revealed a painless, soft and immobile mass in the right anterior side of her neck beneath the sternocleidomastoid muscle, without hyperemia or local heat. On ultrasonographic examination, a hyperechogenic mass was visualized around the thoracic entrance of the right internal jugular vein, which was suggestive of a thrombus. The patient was administered intravenous antibiotic and low‐molecular‐weight heparin followed by oral coumadin as anticoagulant therapy. Her complaints were relieved within 5 days. She was completely well after 6 months. Venous thrombosis generally results from impaired blood flow locally or systemically that leads to activation of coagulation. Primary care physicians should sustain a high index of suspicion in patients who present with undiagnosed swelling in the neck, or other signs and symptoms attributed to IJVT.
Dynamic inversion of the 2000 Tottori earthquake based on elliptical subfault approximations
Authors: Di Carli Sara , François‐Holden Caroline , Peyrat Sophie , Madariaga Raul
Published: December 2010

We propose a simplified nonlinear method for the kinematic and dynamic inversion of near‐field strong motion data at low frequencies. Using a few elliptical patches we reduce the number of independent parameters of the inverse problem. We apply this method to the dynamic inversion of the Western Tottori (Japan) earthquake (Mw 6.6–6.8) of 6 October 2000. Using unfiltered records we relocated the hypocenter close to 14 km in depth. Fifteen records obtained by the KiK‐net and K‐NET accelerometer networks were then filtered to the 0.1–0.5 Hz frequency range and integrated to displacement. We compare observed and synthetic records using the 2 norm. A nonlinear kinematic inversion for the elliptical subfaults is first computed using the neighborhood algorithm (NA). Inversion converges to a slip distribution modeled by just two elliptical patches. We then propose a dynamic inversion method based on the same simple geometrical ideas. Dynamic rupture propagation is computed by finite differences on a coarse numerical grid. Rupture propagation is controlled by a classical slip weakening friction law. Inversion is implemented with the NA for a barrier model. In this model prestress is uniform and rupture propagation is arrested by a simple distribution of barriers. Inversion converges to a model with two elliptical barriers. Synthetics computed for the dynamic inversion fit the observed data, reducing the variance by nearly 60%. By making different assumptions about the rupture process we illustrate the nonuniqueness of the solution to dynamic inversion.
Characterization and comparison of landslide triggering in different tectonic and climatic settings
Authors: Tatard L. , Grasso J. R. , Helmstetter A. , Garambois S.
Published: December 2010

The spatial and temporal distributions of landslides in six catalogues are analyzed in order to better understand landslide triggering mechanisms. The six landslide catalogs are New Zealand, Yosemite (California), Grenoble (French Alps), Val d'Arly (French Alps), Australia, and Wollongong (New South Wales, Australia). Landslides are clustered in time for all catalogs. For New Zealand, Yosemite, Australia, and Wollongong, the frequency of landslides varies between 1 and 1000 events per day and is well fitted by a power law: there is no characteristic scale for daily rates. When the large rates of daily landslides are known to be rain or earthquake triggered, our results suggest the same triggering may hold for the small daily rates. Earthquakes are found to trigger landslides for the New Zealand, Yosemite, and Australia areas at distances as large as 20 times their fault lengths. There is no evidence of landslides triggered by earthquakes for the three other catalogs. Small M ≤ 4 earthquakes have little influence on landslide triggering, if any, for all catalogs. For New Zealand, Yosemite, Val d'Arly, Australia, and Wollongong, the number of landslides per month is significantly correlated with monthly rainfall. A correlation with temperature is found only for Grenoble and New Zealand. Landslide triggering (strong clustering in time and space) is more important in New Zealand than in Grenoble, probably because the forcing (seismicity and climate) is stronger in New Zealand than in the French Alps but possibly also because of a high sensitivity to landslides in New Zealand. We suggest that intensity of clustering in space and time can be used to assess the importance of landslide triggering and the processes responsible for triggering.
Organized melt, seismic anisotropy, and plate boundary lubrication
Authors: Holtzman Benjamin K. , Kendall J.‐Michael
Published: December 2010

Based on observations in both the laboratory and the Earth, we develop the hypothesis that plate boundaries are lubricated by networks of melt‐rich shear zones. Such lubrication would serve to reduce effective strength and focus deformation at plates boundaries. This idea emerges from two sets of observations: (1) stress‐driven melt segregation and organization in experimentally deformed mantle rocks and (2) seismic anisotropy patterns as observed at three divergent plate boundaries (the Ethiopian Rift, the Reykjanes Ridge, and the East Pacific Rise). In all three tectonic settings, the magnitude of anisotropy is greatest at the probable locations of the lithosphere‐asthenosphere boundary within the plate boundary (“marginal LAB”). Seismic anisotropy in the upper mantle is controlled by the lattice preferred orientation (LPO) of predominant olivine and the alignment of melt structures. The observed patterns of anisotropy are controlled by the dip angle of the marginal LAB. When steeply dipping, shear wave splitting in vertically traveling waves (e.g., SKS phases) is most sensitive to the alignment of melt, and surface waves should reveal faster Rayleigh wave velocities than Love wave velocities (VSV > VSH). When shallowly dipping, shear wave splitting in vertically traveling body waves is controlled by olivine LPO, and surface waves show faster Love wave velocities than Rayleigh wave velocities (VSV < VSH). The formation of melt‐rich networks by stress‐driven segregation should be most effective where strain rates are highest. These melt‐lubricated shear zones will reduce effective viscosity relative to the direct extrapolation of viscosity values derived from laboratory creep experiments on homogenous samples. A composite model of anisotropic seismic properties is developed to test the hypothesis that melt segregates along the LAB, incorporating olivine fabrics with oriented and segregated melt over a range of length scales. This model is applied to observations from the three example plate boundaries, leaving the reader to speculate on the implications for interpretation of anisotropy patterns at other geodynamic settings.
Data based quest for solar wind‐magnetosphere coupling function
Authors: Balikhin M. A. , Boynton R. J. , Billings S. A. , Gedalin M. , Ganushkina N. , Coca D. , Wei H.
Published: December 2010

The NARMAX (Nonlinear Autoregressive Moving Average with eXogenous inputs) modeling based approach is used to identify the relations for Solar wind Magnetosphere Coupling Functions in order to identify the one with the best Dst index forecasting abilities. It is argued that the Error Reduction Ratio which is a cornerstone concept in the NARMAX system identification methodology is more appropriate for such nonlinear system as the terrestrial magnetosphere than correlation function analysis which has often been used in the past. It is shown that the identified relationships for coupling functions are proportional to , where is the clock angle, and not to as was suggested in earlier studies. It is shown that the factor appears naturally within the analytical model of Kan and Lee (1979) as the dependence on the clock angle.
Numerical simulation of plasma transport in Saturn's inner magnetosphere using the Rice Convection Model
Authors: Liu X. , Hill T. W. , Wolf R. A. , Sazykin S. , Spiro R. W. , Wu H.
Published: December 2010

We use the Rice Convection Model to simulate plasma transport in Saturn's inner magnetosphere, 2 < L < 12, where L = equatorial distance in planetary radii. By incorporating a continuously active distributed plasma source derived from neutral cloud modeling, the simulation shows alternating longitudinal sectors (“fingers”) of inflow and outflow. Their initial development confirms the retarding effects of the Coriolis force and the pickup current. In their further nonlinear development, the inflow fingers become much narrower in longitude than the outflow ones, which may explain a previously unexplained feature of the Cassini Plasma Spectrometer (CAPS) observations. Our analysis confirms that the narrower inflowing fingers have much larger radial speeds than the broader outflowing sectors. We analyze the corotation lag and find that in the innermost region (L < 5) the pickup current is the major driver of the corotation lag, but in the more distant region (L > 5) both the pickup current and the Coriolis acceleration contribute significantly to the corotation lag. We compare our simulation results with observational results from CAPS data. For the radial flow component, the simulation results fit observations reasonably well. In the azimuthal component, there are significant differences in the magnitude and radial structure of the corotation lag, which may provide guidance for future refinement of the plasma source model.
Estimation of downward long‐wave radiation at the surface combining remotely sensed data and NWP data
Authors: Trigo Isabel F. , Barroso Carla , Viterbo Pedro , Freitas Sandra C. , Monteiro Isabel T.
Published: December 2010

Here we assess established algorithms and a newly developed scheme for the estimation of downward long‐wave radiation flux at the surface (DLR), i.e., the irradiance reaching the surface within 4 and 100 μm. These different methods correspond to bulk parameterization schemes, which merge the signature of clouds on Meteosat second‐generation (MSG) data with information on atmosphere water content and near‐surface air temperature available from numerical weather prediction (NWP) fields. The new formulation consists of a generalization of a method first developed for clear sky cases and now fine‐tuned for a wider range of atmospheric conditions. The performance of this and three other parameterization schemes is compared with independent ground observations. Such a validation exercise is extended also to European Centre for Medium‐Range Weather Forecast (ECMWF) flux forecasts, since the ECMWF model is the main source of information on air temperature and water vapor content, and to surface fluxes obtained from the Clouds and the Earth's Radiant Energy System (CERES). It is shown that the new parameterization scheme performs well when compared to other methods, with root mean square errors within 20 Wm−2. The overall good matching between parameterized values and in situ data suggests a good performance of a relatively simple bulk scheme and also of the use of MSG‐based cloud identification.
Comparison of one-particle basis set extrapolation to explicitly correlated methods for the calculation of accurate quartic force fields, vibrational frequencies, and spectroscopic constants: Application to H2O, N2H+, NO2+, and C2H2
Authors: Huang Xinchuan , Valeev Edward F. , Lee Timothy J.
Published: December 2010

One-particle basis set extrapolation is compared with one of the new R12 methods for computing highly accurate quartic force fields (QFFs) and spectroscopic data, including molecular structures, rotational constants, and vibrational frequencies for the H2O, N2H+, NO2+, and C2H2 molecules. In general, agreement between the spectroscopic data computed from the best R12 and basis set extrapolation methods is very good with the exception of a few parameters for N2H+ where it is concluded that basis set extrapolation is still preferred. The differences for H2O and NO2+ are small and it is concluded that the QFFs from both approaches are more or less equivalent in accuracy. For C2H2, however, a known one-particle basis set deficiency for C–C multiple bonds significantly degrades the quality of results obtained from basis set extrapolation and in this case the R12 approach is clearly preferred over one-particle basis set extrapolation. The R12 approach used in the present study was modified in order to obtain high precision electronic energies, which are needed when computing a QFF. We also investigated including core-correlation explicitly in the R12 calculations, but conclude that current approaches are lacking. Hence core-correlation is computed as a correction using conventional methods. Considering the results for all four molecules, it is concluded that R12 methods will soon replace basis set extrapolation approaches for high accuracy electronic structure applications such as computing QFFs and spectroscopic data for comparison to high-resolution laboratory or astronomical observations, provided one uses a robust R12 method as we have done here. The specific R12 method used in the present study, CCSD(T)R12, incorporated a reformulation of one intermediate matrix in order to attain machine precision in the electronic energies. Final QFFs for N2H+ and NO2+ were computed, including basis set extrapolation, core-correlation, scalar relativity, and higher-order correlation and then used to compute highly accurate spectroscopic data for all isotopologues. Agreement with high-resolution experiment for 14N2H+ and 14N2D+ was excellent, but for 14N16O2+ agreement for the two stretching fundamentals is outside the expected residual uncertainty in the theoretical values, and it is concluded that there is an error in the experimental quantities. It is hoped that the highly accurate spectroscopic data presented for the minor isotopologues of N2H+ and NO2+ will be useful in the interpretation of future laboratory or astronomical observations.
Lock-exchange experiments with an autocatalytic reaction front
Authors: Malham I. Bou , Jarrige N. , Martin J. , Rakotomalala N. , Talon L. , Salin D.
Published: December 2010

A viscous lock-exchange gravity current corresponds to the reciprocal exchange of two fluids of different densities in a horizontal channel. The resulting front between the two fluids spreads as the square root of time, with a diffusion coefficient reflecting the buoyancy, viscosity, and geometrical configuration of the current. On the other hand, an autocatalytic reaction front between a reactant and a product may propagate as a solitary wave, namely, at a constant velocity and with a stationary concentration profile, resulting from the balance between molecular diffusion and chemical reaction. In most systems, the fluid left behind the front has a different density leading to a lock-exchange configuration. We revisit, with a chemical reaction, the classical situation of lock-exchange. We present an experimental analysis of buoyancy effects on the shape and the velocity of the iodate arsenous acid autocatalytic reaction fronts, propagating in horizontal rectangular channels and for a wide range of aspect ratios (1/3 to 20) and cylindrical tubes. We do observe stationary-shaped fronts, spanning the height of the cell and propagating along the cell axis. Our data support the contention that the front velocity and its extension are linked to each other and that their variations scale with a single variable involving the diffusion coefficient of the lock-exchange in the absence of chemical reaction. This analysis is supported by results obtained with lattice Bathnagar-Gross-Krook (BGK) simulations Jarrige et al. [Phys. Rev. E 81, 06631 (2010)], in other geometries (like in 2D simulations by Rongy et al. [J. Chem. Phys. 127, 114710 (2007)] and experiments in cylindrical tubes by Pojman et al. [J. Phys. Chem. 95, 1299 (1991)]), and for another chemical reaction Schuszter et al. [Phys. Rev. E 79, 016216 (2009)].
The Zeeman effect and hyperfine interactions in J = 1–0 transitions of CH+ and its isotopologues
Authors: Amano T.
Published: December 2010

The J = 1 − 0 transitions of \documentclass[12pt]{minimal}\begin{document}$^{12}$\end{document}12CH \documentclass[12pt]{minimal}\begin{document}$^+$\end{document}+, \documentclass[12pt]{minimal}\begin{document}$^{13}$\end{document}13CH \documentclass[12pt]{minimal}\begin{document}$^+$\end{document}+, and \documentclass[12pt]{minimal}\begin{document}$^{12}$\end{document}12CD \documentclass[12pt]{minimal}\begin{document}$^+$\end{document}+ in the ground \documentclass[12pt]{minimal}\begin{document}$X^1\Sigma ^+$\end{document}X1Σ+ state have been unambiguously identified by using an extended negative glow discharge as an ion source. Unexpectedly large Zeeman splittings have been observed, and the \documentclass[12pt]{minimal}\begin{document}$^{13}$\end{document}13CH \documentclass[12pt]{minimal}\begin{document}$^+$\end{document}+ line exhibits nuclear spin-rotation hyperfine splitting in addition to the Zeeman effect. The nuclear spin-rotation coupling constant was determined to be 1.087(50) MHz for the \documentclass[12pt]{minimal}\begin{document}$^{13}$\end{document}13C species. The rotational g-factor is found to be –7.65(29), in terms of the nuclear magneton for the J = 1 and v = 0 state, more than an order of magnitude larger than values for typical diamagnetic closed shell molecules. These larger than usual magnetic interactions for a \documentclass[12pt]{minimal}\begin{document}$^1\Sigma$\end{document}1Σ molecule are caused by the large rotational energy and relatively small excitation energy of the excited \documentclass[12pt]{minimal}\begin{document}$A^1\Pi$\end{document}A1Π state. The effective g-factor and the spin-rotation coupling constant obtained by ab initio calculations agree very well with the experimentally determined values.
The effect of attractions on the local structure of liquids and colloidal fluids
Authors: Taffs Jade , Malins Alex , Williams Stephen R. , Royall C. Patrick
Published: December 2010

We revisit the role of attractions in liquids and apply these concepts to colloidal suspensions. Two means are used to investigate the structure; the pair correlation function and a recently developed topological method. The latter identifies structures topologically equivalent to ground state clusters formed by isolated groups of 5 ⩽ m ⩽ 13 particles, which are specific to the system under consideration. Our topological methodology shows that, in the case of Lennard-Jones, the addition of attractions increases the system's ability to form larger (m ⩾ 8) clusters, although pair-correlation functions are almost identical. Conversely, in the case of short-ranged attractions, pair correlation functions show a significant response to adding attraction, while the liquid structure exhibits a strong decrease in clustering upon adding attractions. Finally, a compressed, weakly interacting system shows a similar pair structure and topology.
Dynamics and mechanism of the non-adiabatic transitions from the ungerade I2(D0+u) state induced by collisions with rare gas atoms
Authors: Akopyan M. E. , Khadikova E. I. , Lukashov S. S. , Poretsky S. A. , Pravilov A. M. , Buchachenko A. A. , Suleimanov Yu. V.
Published: December 2010

The stepwise three-photon two-color laser excitation scheme is used for selective population of the first-tier ion-pair D0+u state of molecular iodine. Collection and analysis of the luminescence after the excitation of the vD = 6, 8, 13 and 18 vibronic levels of the D state in the pure iodine vapor and the gas-phase mixtures with He, Ar and Xe provide the total and, whenever possible, partial rate constants for the collision-induced non-adiabatic transitions to the other ion-pair states of the first tier. Comparison with the analogous data obtained previously for the non-adiabatic transitions from the E0+g state reveals the similarity between two cases. For He, the D ↔ E transitions are preferable, whereas for Ar and Xe transitions to the D′ and β states dominate at vD = 6, 8 and 13, in accord with the statistical considerations. Efficient population of the δ state at vD = 18 in Ar and Xe is the most prominent non-statistical feature observed. The vibrational product state distributions for the D → E transitions are also obtained. In contrast to the previously studied E → D transition, they show significant positive vibronic energy transfer. The measurements for He and Ar are accompanied by the quantum scattering calculations that reproduce well the main qualitative features of the experimental results.
Universality of non-Ohmic shunt leakage in thin-film solar cells
Authors: Dongaonkar S. , Servaites J. D. , Ford G. M. , Loser S. , Moore J. , Gelfand R. M. , Mohseni H. , Hillhouse H. W. , Agrawal R. , Ratner M. A. , Marks T. J. , Lundstrom M. S. , Alam M. A.
Published: December 2010

We compare the dark current-voltage (IV) characteristics of three different thin-film solar cell types: hydrogenated amorphous silicon (a-Si:H) p-i-n cells, organic bulk heterojunction (BHJ) cells, and Cu(In,Ga)Se2 (CIGS) cells. All three device types exhibit a significant shunt leakage current at low forward bias (V<∼0.4) and reverse bias, which cannot be explained by the classical solar cell diode model. This parasitic shunt current exhibits non-Ohmic behavior, as opposed to the traditional constant shunt resistance model for photovoltaics. We show here that this shunt leakage (Ish), across all three solar cell types considered, is characterized by the following common phenomenological features: (a) voltage symmetry about V=0, (b) nonlinear (power law) voltage dependence, and (c) extremely weak temperature dependence. Based on this analysis, we provide a simple method of subtracting this shunt current component from the measured data and discuss its implications on dark IV parameter extraction. We propose a space charge limited (SCL) current model for capturing all these features of the shunt leakage in a consistent framework and discuss possible physical origin of the parasitic paths responsible for this shunt current mechanism.
New sample cell configuration for wide-frequency dielectric spectroscopy: DC to radio frequencies
Authors: Nakanishi Masahiro , Sasaki Yasutaka , Nozaki Ryusuke
Published: December 2010

A new configuration for the sample cell to be used in broadband dielectric spectroscopy is presented. A coaxial structure with a parallel plate capacitor (outward parallel plate cell: OPPC) has made it possible to extend the frequency range significantly in comparison with the frequency range of the conventional configuration. In the proposed configuration, stray inductance is significantly decreased; consequently, the upper bound of the frequency range is improved by two orders of magnitude from the upper limit of conventional parallel plate capacitor (1 MHz). Furthermore, the value of capacitance is kept high by using a parallel plate configuration. Therefore, the precision of the capacitance measurement in the lower frequency range remains sufficiently high. Finally, OPPC can cover a wide frequency range (100 Hz–1 GHz) with an appropriate admittance measuring apparatus such as an impedance or network analyzer. The OPPC and the conventional dielectric cell are compared by examining the frequency dependence of the complex permittivity for several polar liquids and polymeric films.
Aggregation work at polydisperse micellization: Ideal solution and “dressed micelle” models comparing to molecular dynamics simulations
Authors: Burov S. V. , Shchekin A. K.
Published: December 2010

General thermodynamic relations for the work of polydisperse micelle formation in the model of ideal solution of molecular aggregates in nonionic surfactant solution and the model of “dressed micelles” in ionic solution have been considered. In particular, the dependence of the aggregation work on the total concentration of nonionic surfactant has been analyzed. The analogous dependence for the work of formation of ionic aggregates has been examined with regard to existence of two variables of a state of an ionic aggregate, the aggregation numbers of surface active ions and counterions. To verify the thermodynamic models, the molecular dynamics simulations of micellization in nonionic and ionic surfactant solutions at two total surfactant concentrations have been performed. It was shown that for nonionic surfactants, even at relatively high total surfactant concentrations, the shape and behavior of the work of polydisperse micelle formation found within the model of the ideal solution at different total surfactant concentrations agrees fairly well with the numerical experiment. For ionic surfactant solutions, the numerical results indicate a strong screening of ionic aggregates by the bound counterions. This fact as well as independence of the coefficient in the law of mass action for ionic aggregates on total surfactant concentration and predictable behavior of the “waterfall” lines of surfaces of the aggregation work upholds the model of “dressed” ionic aggregates.
An efficient magneto-optical trap of metastable krypton atoms
Authors: Cheng C.-F. , Jiang W. , Yang G.-M. , Sun Y.-R. , Pan H. , Gao Y. , Liu A.-W. , Hu S.-M.
Published: December 2010

We report a magneto-optical trap of metastable krypton atoms with a trap loading rate of \documentclass[12pt]{minimal}\begin{document}$3\times 10^{11}$\end{document}3×1011 atoms/s and a trap capture efficiency of \documentclass[12pt]{minimal}\begin{document}$3\times 10^{-5}$\end{document}3×10−5. The system starts with an atomic beam of metastable krypton produced in a liquid-nitrogen cooled, radio-frequency driven discharge. The metastable beam flux emerging from the discharge is \documentclass[12pt]{minimal}\begin{document}$1.5\times 10^{14}$\end{document}1.5×1014 atoms/s/sr. The flux in the forward direction is enhanced by a factor of 156 with transverse laser cooling. The atoms are then slowed inside a Zeeman slower before captured by a magneto-optic trap. The trap efficiency can be further improved, possibly to the \documentclass[12pt]{minimal}\begin{document}$10^{-2}$\end{document}10−2 level, by gas recirculation. Such an atom trap is useful in trace analysis applications where available sample size is limited.
Can we make a Bohmian electron reach the speed of light, at least for one instant?
Authors: Tausk Daniel V. , Tumulka Roderich
Published: December 2010

In Bohmian mechanics, a version of quantum mechanics that ascribes world lines to electrons, we can meaningfully ask about an electron's instantaneous speed relative to a given inertial frame. Interestingly, according to the relativistic version of Bohmian mechanics using the Dirac equation, a massive particle's speed is less than or equal to the speed of light, but not necessarily less. That is, there are situations in which the particle actually reaches the speed of light—a very nonclassical behavior. That leads us to the question of whether such situations can be arranged experimentally. We prove a theorem, Theorem 5, implying that for generic initial wave functions the probability that the particle ever reaches the speed of light, even if at only one point in time, is zero. We conclude that the answer to the question is no. Since a trajectory reaches the speed of light whenever the quantum probability current \documentclass[12pt]{minimal}\begin{document}$\overline{\psi }\gamma ^\mu \psi$\end{document}ψ¯γμψ is a lightlike 4-vector, our analysis concerns the current vector field of a generic wave function and may thus be of interest also independently of Bohmian mechanics. The fact that the current is never spacelike has been used to argue against the possibility of faster-than-light tunneling through a barrier, a somewhat similar question. Theorem 5, as well as a more general version provided by Theorem 6, are also interesting in their own right. They concern a certain property of a function \documentclass[12pt]{minimal}\begin{document}$\psi :\mathbb {R}^4\rightarrow \mathbb {C}^4$\end{document}ψ:R4→C4 that is crucial to the question of reaching the speed of light, namely being transverse to a certain submanifold of \documentclass[12pt]{minimal}\begin{document}$\mathbb {C}^4$\end{document}C4 along a given compact subset of space-time. While it follows from the known transversality theorem of differential topology that this property is generic among smooth functions \documentclass[12pt]{minimal}\begin{document}$\psi :\mathbb {R}^4\rightarrow \mathbb {C}^4$\end{document}ψ:R4→C4, Theorem 5 asserts that it is also generic among smooth solutions of the Dirac equation.
The role of atomic excited states of Au on N2O capture and activation: A multireference second-order perturbation theory study
Authors: Olvera-Neria Oscar , Bertin Virineya , Poulain Enrique
Published: December 2010

Nitrous oxide (N2O) is an intermediate compound formed during catalysis occurring in automobile exhaust pipes. Atomic Au in its ground state is unable to react with N2O, however, several Au excited states are bound to N2O, but not all of these states are able to activate N2O bonds. In this work, N2O capture and activation by a single Au atom are studied considering Au in the ground and excited states with multiplicities = 2, 4 and 6. The Au + N2O reactions are studied at multireference second-order perturbation level of theory using Cs symmetry. The AuN2O (4A′, 4A′′, 6A′ and 6A′′) adducts are spontaneously created from Au excited states. From these complexes, only the 4A′, 6A′ and 6A′′ states exhibit N2O activation reaction paths yielding N2, NO and O atoms as end products when N2O approaches Au excited states side-on. Cations both ground and excited states, capture N2O although only the Au+ (5A′) + N2O (1Σ+) → NAuNO+ (5A′) reaction (for the end-on and side-on approaches) shows N2O activation with N–N bond breaking. In the case of Au anions, the ground state and most of the excited states capture N2O and activation takes place according to Au− (3A′, 5A′, 5A′′) + N2O (1Σ+) → AuO− (3A′, 5A′, 5A′′) + N2(g) for the N2O end-on approach by the oxygen atom. The reaction paths show a metal-gas dative covalent bonding character. Mulliken charge population analysis obtained for the active states shows that the binding is done through charge donation and retro-donation between the metal and the N2O molecule.