bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of Anastomotic Leak and its Prognosis in Digestive Surgery
Authors: Haga Yoshio , Wada Yasuo , Takeuchi Hitoshi , Ikejiri Koji , Ikenaga Masakazu
Published: December 2010

Background

Anastomotic leak (AL) is a dangerous postoperative complication in gastrointestinal surgery. The present study focuses on whether our prediction scoring system, “Estimation of Physiologic Ability and Surgical Stress” (E‐PASS), could predict occurrence of AL and its prognosis in various kinds of gastrointestinal surgical procedures.

Methods

We prospectively investigated parameters of E‐PASS, absence or presence of AL, and in‐hospital mortality in 6,005 patients who underwent elective digestive surgery with alimentary tract reconstruction in 45 acute care hospitals in Japan between 1 April 2002 and 31 March 2007.

Results

Incidences of AL were 19.6% for esophagectomy via right thoracotomy and laparotomy, 11.7% for pancreaticoduodenectomy, 7.4% for low anterior resection, 4.0% for total gastrectomy, 1.8% for open distal gastrectomy, 1.3% for open colectomy, for an overall incidence of 4.1%. The incidence in each procedure significantly correlated with median value of surgical stress score of the E‐PASS (R = 0.78, n = 11, p = 0.0048). The incidences of AL increased when Total Risk Points (TRP) of the E‐PASS increased; 1.1% at the TRP range of <500, 2.8% at 500 to <1,000, 4.8% at 1,000 to <1,500, and 13.6% at ≥1,500 (p < 0.0001). In patients who suffered from AL, an in‐hospital mortality rate at TRP < 1,000 was significantly lower than that at TRP of ≥1,000 (1.1 vs. 15.9%; p = 0.00019).

Conclusions

The E‐PASS, requiring only nine variables, may be useful in predicting AL and its prognosis.
Arachidonic Acid Induces Production of 17,20β‐Dihydroxy‐4‐pregnen‐3‐one (DHP) via a Putative PGE2 Receptor in Fish Follicles from the Eurasian Perch
Authors: Henrotte E. , Milla S. , Mandiki S. N. M. , Kestemont P.
Published: December 2010

The effects of docosahexaenoic, eicosaenoic and arachidonic acids (DHA, EPA and ARA, respectively) on sex‐steroid and prostaglandin (PG) production were investigated in Eurasian perch (Perca fluviatilis) follicles using an in‐ vitro incubation technique. Only ARA was able to induce the production of 17,20β‐dihydroxy‐4‐pregnen‐3‐one (DHP), the hormone produced by vitellogenic follicles undergoing final meiotic maturation, as well as the production of PGE2 and PGF2α by the follicles. This work also investigated, using a preliminary pharmacological approach, the presence of a functional PGE2‐like receptor in fish follicles. Exogenous PGE2 and butaprost (specific agonist of the EP2 receptor) stimulated DHP production. A second experiment assayed the cyclic adenosine monophosphate (cAMP) production by the follicles after 24 h of incubation with the agonist and antagonist of the EP2 receptor. As observed in mammals, we concluded that the cAMP produced in response to PGE2 was probably mediated by an intracellular mechanism via a PGE2‐like receptor. This is the first pharmacological indication of this type of receptors in fish follicles. This study also indicates that ARA, and its derivatives, PGE2 and PGF2α, may act on final follicle maturation in Eurasian perch.
The influence of brace type on the success rate of the Ponseti treatment protocol for idiopathic clubfoot
Authors: Hemo Yoram , Segev Eitan , Yavor Ariella , Ovadia Dror , Wientroub Shlomo , Hayek Shlomo
Published: December 2010

Purpose

The success of the Ponseti method for treating idiopathic clubfoot deformity is dependent on the casting techniques and the adherence of the patient to the foot abduction brace protocol. Newly developed brace designs claim to be more comfortable, to be easier to use and to prevent dislodgement of the foot from the brace, making them more efficient and improving patient compliance. They are, however, more costly, and, therefore, accessible to fewer patients. We compared the compliance and treatment outcome using two brace designs, the traditional simple brace of pre-walking shoes attached to a Dennis Browne (DB) bar and the new sophisticated Mitchell brace.

Methods

We compared the functional outcome and compliance with the post-corrective bracing protocol of 38 children with idiopathic clubfoot treated in our institution using two brace designs. Twenty-one chose the DB brace and 17 chose the Mitchell brace.

Results

There was no difference in the compliance rate or in the final clinical and radiological outcomes of the two groups after a minimum of 2 years of follow-up. A positive correlation was found between the Pirani score at the beginning of treatment and the final functional score for both groups. Both groups were satisfied with the selected brace. Both groups were equally compliant with the brace protocol.

Conclusion

We conclude that new and more expensive brace designs do not necessarily provide better clinical results. Fully corrected foot and a strong family–treating team partnership are crucial to adherence with the brace protocol.
Intrusion and deformation at Campi Flegrei, southern Italy: Sills, dikes, and regional extension
Authors: Woo Judith Y. L. , Kilburn Christopher R. J.
Published: December 2010

The Campi Flegrei volcanic district, in southern Italy, has been uplifted since 1968 by a net maximum of 3 m during the intervals 1968–1972 and 1982–1984. The uplift represents a permanent deformation against a background rate of subsidence of about 17 mm a−1. Previous models have reproduced the observed vertical deformation but not the full pattern of horizontal movements. The 1982–1983 deformation is here reanalyzed in terms of a penny‐shaped sill on its own, with a tabular surface protrusion, or in an extensional stress field. It can be explained best by the intrusion of a sill (of 0.03–0.04 km3 at a depth of 2.75 km) in a crust that is being stretched ESE‐WNW at a strain rate of about 5.6 × 10−5 a−1. The sill's volume is similar to the common volumes of Campi Flegrei's eruptions since the Neapolitan Yellow Tuff (NYT) caldera was formed 15.6 ka ago. This similarity and the permanent nature of the uplift favor magmatic intrusion as the primary source of unrest. Sill formation may thus reflect the spreading of magma at a level of neutral buoyancy or along lateral discontinuities in the crust. The southern part of the caldera has been shielded from post‐NYT eruptions, despite some 33 m of permanent uplift since Roman times. Precursors to eruptions may thus be related not to caldera‐wide uplift but to the preceding conditions that determine whether magma ascends beneath the southern part of the caldera (favoring sill intrusion) or elsewhere (favoring an eruption).
Active tectonics in northern Victoria Land (Antarctica) inferred from the integration of GPS data and geologic setting
Authors: Dubbini M. , Cianfarra P. , Casula G. , Capra A. , Salvini F.
Published: December 2010

A semipermanent Global Positioning System (GPS) network of 30 vertices known as the Victoria Land Network for Deformation Control (VLNDEF) was set up in the Austral summer of 1998 in northern Victoria Land (NVL), including Terra Nova Bay (TNB), Antarctica. The locations were selected according to the known Cenozoic fault framework, which is characterized by a system of NW‐SE regional faults with right‐lateral, strike‐slip kinematics. The TNB1 permanent GPS station is within the VLNDEF, and following its installation on a bedrock monument in October 1998, it has been recording almost continuously. The GPS network has been surveyed routinely every two summers, using high‐quality, dual‐frequency GPS receivers. In this study we present the results of a distributed session approach applied to the processing of the GPS data of the VLNDEF. An improved reference frame definition was implemented, including a new Euler pole, to compute the Antarctic intraplate residual velocities. The projection of the residual velocities on the main faults in NVL show present‐day activities for some faults, including the Tucker, Leap Year, Lanterman, Aviator, and David faults, with right‐lateral strike‐slip kinematics and local extensional and compressional components. This active fault pattern divides NVL into eight rigid blocks, each characterized by its relative movements and rigid rotations. These show velocities of up to several millimeters per year, which are comparable to those predicted by plate tectonic theory at active plate margins.
Ancient Tree Ring Archives in the U.S. Great Lakes Region
Authors: Panyushkina Irina P. , Leavitt Steven W.
Published: December 2010

Rather than being a seamless transition from Late Glacial Maximum to the start of the Holocene between 15,000 and 8000 years ago, the warming during this period was punctuated by abrupt climatic instabilities. These include the Younger Dryas cold event, the Preboreal Oscillation, and an isolated cooling event around 8200 years ago (see Figure 1, bottom right).
Budget Realities Could Put Damper on Some NOAA Programs
Authors: Showstack Randy
Published: December 2010

The fall meeting of the National Oceanic and Atmospheric Administration's (NOAA) Science Advisory Board was in part a study in contrasts: discussing the agency's vision, goals, and recent successes while facing the harsh economic and political landscape that will make it difficult for NOAA to receive sufficient funding for the current fiscal year (FY 2011) to do little more than tread water toward reaching some of those goals.
Major Changes in AGU Publication Fees
Authors: Cook Bill
Published: December 2010

Effective with any manuscript submitted after 31 December 2010, AGU is eliminating color charges in all formats. At the same time that we eliminate color charges, we are simplifying publication fees. Articles published in Journal of Geophysical Research; Geochemistry, Geophysics, Geosystems; and Radio Science will each have a flat fee of $1000, and Geophysical Research Letters (GRL) articles will each have a flat fee of $500. These prices represent a small drop from the average cost currently paid by authors. We will retain the excess page charges for full articles longer than 13 pages (including Water Resources Research) and 4 pages for letters, comments, and replies. This simplification means we can streamline the “calculator” authors must use when submitting manuscripts to AGU.
Fellows Celebrated at Fall Meeting
Authors: Anonymous
Published: December 2010

The 2010 AGU Fellows will be presented during the Fall Meeting Honors Tribute in San Francisco, Calif. The formal ceremony will be held on Wednesday, 15 December 2010. President‐Elect Carol Finn will introduce each Fellow and read a brief statement of the achievements for which each has been selected.
Crustal structure beneath the Indochina peninsula from teleseismic receiver functions
Authors: Bai Ling , Tian Xiaobo , Ritsema Jeroen
Published: December 2010

We analyze teleseismic receiver functions to determine the crustal structure beneath the Indochina peninsula which is located immediately south‐east of the eastern Himalayan syntaxis basin. We found that the Indochina peninsula is characterized by a thin (∼31 km) crust with a low Vp/Vs ratio (∼1.68). The intra‐lower crustal low‐velocity zone (LVZ) is observed beneath the northwestern part of our study region. We hypothesize that it is an extension of the lower crustal LVZ observed beneath the southeastern Tibet and the South China block and that it terminates at the Dien Bien Phu Fault (DBPF). A LVZ observed in the upper crust beneath southeast of the DBPF indicates that the crust is ductile and earthquakes are rare.
Magnetospheric period oscillations at Saturn: Comparison of equatorial and high‐latitude magnetic field periods with north and south Saturn kilometric radiation periods
Authors: Andrews D. J. , Coates A. J. , Cowley S. W. H. , Dougherty M. K. , Lamy L. , Provan G. , Zarka P.
Published: December 2010

It has recently been shown using Cassini radio data that Saturn kilometric radiation (SKR) emissions from the Northern and Southern hemispheres of Saturn are modulated at distinctly different periods, ∼10.6 h in the north and ∼10.8 h in the south, during the southern summer conditions that prevailed during the interval from 2004 to near‐equinox in mid‐2009. Here we examine Cassini magnetospheric magnetic field data over the same interval and show that two corresponding systems of magnetic field oscillations that have the same overall periods, as the corresponding SKR modulations, to within ∼0.01% are also present. Specifically, we show that the rotating quasi‐dipolar field perturbations on southern open field lines and the rotating quasi‐uniform field in the inner region of closed field lines have the same period as the southern SKR modulations, although with some intervals of slow long‐term phase drift of unknown origin, while the rotating quasi‐dipolar field perturbations on northern open field lines have the same period as the northern SKR modulations. We also show that while the equatorial quasi‐uniform field and effective southern transverse dipole are directed down tail and toward dawn at southern SKR maxima, as found in previous studies, the corresponding northern transverse dipole is directed approximately opposite, pointing sunward and also slightly toward dawn at northern SKR maxima. We discuss these findings in terms of the presence of two independent high‐latitude field‐aligned current systems that rotate with different periods in the two hemispheres.
Modeling dynamics and thermodynamics of icebergs in the Barents Sea from 1987 to 2005
Authors: Keghouche I. , Counillon F. , Bertino L.
Published: December 2010

A modeling study of iceberg drift characteristics in the Barents and Kara seas for the period 1987–2005 is presented. Maps of iceberg density and potential locations subject to grounding complement sparse existing oceanographic and aerial field survey campaigns. The model suggests preferential pathways from the most important calving sources. Icebergs originating from Franz Josef Land have the largest spread over the domain. Simulations confirm the previously observed seasonal cycle of the southernmost extent of the icebergs. Strong interannual variability of the iceberg extent with a weak decreasing trend occurs, similar to the observed sea ice extent. Analysis of the atmospheric forcing reveals that years with anomalous northerly winds enhance the southward iceberg extension. Northerly winds also have a positive delayed impact on the iceberg extent. They limit the inflow of Atlantic Water into the Barents Sea and, therefore, its heat content the following year, increasing the mean age of icebergs and thus their potential extension. Finally, the model is able to reproduce the observed extreme iceberg extension southeast of the Barents Sea in May 2003.
Using repeated patterns in snow distribution modeling: An Arctic example
Authors: Sturm Matthew , Wagner Anna M.
Published: December 2010

Snow distribution patterns are similar from one year to the next because they are largely controlled by the interaction of topography, vegetation, and consistent synoptic weather patterns. On a yearly basis none of these controls changes radically. As a consequence, deep and shallow areas of snow tend to be fixed in space, producing depth differences that may vary in absolute, but not relative, amounts from year to year. While this fact is widely known, the use of patterns in modeling snow cover distribution is limited. Here, on the basis of a training set of nine annual snow depth surveys from a small tundra basin in Alaska, we identify the climatological snow distribution pattern (CSDP). Using this and a few depth measurements, the snow distribution for years that were not included in the training set is predicted and mapped with a near‐zero bias and RMSE that ranged from 4.4 to 10.4 cm. The accuracy of this strictly empirical approach to modeling the depth distribution is similar to, or better than, the output from a weather‐driven physically based snow model. However, in our view a hybrid approach is best. Ingesting the CSDP into SnowModel, a widely used numerical code that simulates snow processes, the accuracy of the model output is improved by up to 60%. This hybrid approach retains the advantages of running a weather‐driven numerical code but adds spatial accuracy currently only obtainable from observed snow patterns. The patterns can be captured in several ways, including aerial photography or satellite remote sensing during snowmelt.
Associations of Visceral and Liver Fat With the Metabolic Syndrome Across the Spectrum of Obesity: The AGES‐Reykjavik Study
Authors: Kim Lauren J. , Nalls Michael A. , Eiriksdottir Gudny , Sigurdsson Sigurdur , Launer Lenore J. , Koster Annemarie , Chaves Paulo H.M. , Jonsdottir Birna , Garcia Melissa , Gudnason Vilmundur , Harris Tamara B. ,   For the AGES‐Reykjavik Study Investigators
Published: December 2010

Visceral adipose tissue (VAT) is a key pathogenic fat depot in the metabolic syndrome (MetS), but liver fat (LF) may also play an important role. We evaluated associations of VAT and LF with MetS in normal weight, overweight, and obese men and women (BMI <25, 25–29.9, and ≥30 kg/m2, respectively). This analysis included 2,495 participants from the Age, Gene/Environment Susceptibility (AGES)–Reykjavik study with computed tomography measurements for VAT and LF. MetS was defined by ≥3 of the following: larger abdominal circumference, hypertension, elevated triglyceride (TG), low high‐density lipoprotein (HDL), impaired fasting glucose (IFG), and microalbuminuria. We estimated the odds of MetS per 1‐s.d. increase in VAT and LF, adjusting for key covariates. VAT was associated with an increased odds of MetS in normal weight, overweight, and obese women (odds ratios (OR) = 2.78, 1.63, and 1.43, respectively; all P < 0.01) that diminished in magnitude with increasing BMI (VAT × BMI class interaction P < 0.001). In men, VAT was related to MetS only among the overweight (OR = 1.69, P < 0.01). LF was associated with MetS in the overweight and obese groups in women (OR = 1.38 and 1.45; both P < 0.001) and in men (OR = 1.38, P = 0.01; and OR = 1.27, P = 0.10), but not in the normal weight groups. These BMI‐specific relationships persisted when both fat depots were included in the model. VAT and LF were associated with MetS independently of each other, and these relationships were modified by BMI class such that, VAT was the more important depot at lower levels of obesity and LF at higher levels. Importantly, fatty liver may be a novel metabolic risk factor in overweight and obese individuals.
Association of BMI and Cardiovascular Risk Stratification in the Elderly African‐American Females
Authors: Javed Fahad , Aziz Emad F. , Sabharwal Manpreet S. , Nadkarni Girish N. , Khan Shahzeb A. , Cordova Juan P. , Benjo Alexandre M. , Gallagher Dympna , Herzog Eyal , Messerli Franz H. , Pi‐Sunyer F. Xavier
Published: December 2010

We aimed to estimate the association of BMI and risk of systemic hypertension in African‐American females aged 65 years and older. In this retrospective, cross‐sectional study, medical charts were randomly reviewed after obtaining institutional review board approval and data collection was conducted for height, weight, BMI, age, ethnicity, gender, and hypertension. A multivariable logistic regression analysis was performed. The mean BMI was significantly higher in hypertensive subjects than normotensives (30.3 vs. 29 kg/m2; P = 0.003). A higher proportion of hypertensive subjects had a BMI >23 kg/m2 as compared to normotensives (88.9% vs. 83.5%; P = 0.023). When the log odds of having a history of hypertension was plotted against BMI as a continuous variable, we found that the odds showed an increasing trend with increasing BMI and a steep increase after a BMI of 23 kg/m2. When BMI was analyzed as a categorical variable, a BMI of 23–30 kg/m2 was found to have an odds ratio of 1.43 (95% confidence interval 1.01–2.13; P = 0.05) and a BMI of >30 kg/m2 had an odds ratio of 1.76 (95% confidence interval 1.17–2.65; P = 0.007) when compared to a BMI of <23 kg/m2. This association remained significant in both univariate and multivariate analysis. We conclude that BMI is an independent predictor of hypertension in elderly African‐American females. Our results indicate that the risk of hypertension increased significantly at BMI of >23 kg/m2 in this ethnic group. Weight reduction to a greater extent than previously indicated could play an integral role in prevention and control of high blood pressure in this particular population.
High Leptin/Adiponectin Ratio and Serum Triglycerides Are Associated With an “At‐Risk” Phenotype in Young Severely Obese Patients
Authors: Labruna Giuseppe , Pasanisi Fabrizio , Nardelli Carmela , Caso Rosanna , Vitale Dino F. , Contaldo Franco , Sacchetti Lucia
Published: December 2010

“At‐risk” severely obese subjects are characterized by insulin resistance, and higher visceral fat and plasma lipid levels compared with metabolically healthy obese (MHO) subjects, although both groups have a high BMI and fat mass. The aim of this study was to measure several serum adipokines and gastrointestinal hormones in a young severely obese population from Southern Italy to identify biochemical markers of the “at‐risk” insulin‐resistant obese profile. We studied 160 unrelated white young adults (mean age = 25.2 years, mean BMI = 44.9 kg/m2, 65% women) affected by obesity for at least 5 years. Serum concentrations of glucagon, ghrelin, gastric inhibitory peptide, glucagon like peptide‐1, interleukin‐6, tumor necrosis factor α, leptin, adiponectin, adipsin, and visfatin were measured. The leptin/adiponectin (L/A) ratio and fatty liver index (FLI) were calculated. We found a prevalence of 21.3% of MHO patients in our young severely obese patients. At univariate analysis, the “at‐risk” group had higher mean levels of BMI (P < 0.0001), leptin (P = 0.039, men) and the L/A ratio (P = 0.003), and lower mean levels of visfatin (P = 0.026) than the MHO group. The L/A ratio, serum triglycerides, and male sex were significantly associated with “at‐risk” obesity and accounted for 19.5% of insulin resistance at multivariate analysis. In conclusion, we demonstrate that a high serum L/A ratio and high levels of serum triglycerides may be markers of “at‐risk” obesity, independent of waist circumference (WC) and BMI, in young severely obese population.
Effect of Diet With and Without Exercise Training on Markers of Inflammation and Fat Distribution in Overweight Women
Authors: Fisher Gordon , Hyatt Tanya C. , Hunter Gary R. , Oster Robert A. , Desmond Renee A. , Gower Barbara A.
Published: December 2010

The independent effects of exercise and weight loss on markers of inflammation (MOI) in obese individuals have not been clearly characterized. The objectives of this study were to: (i) identify the independent effects of exercise and weight loss on MOI and (ii) determine whether changes in MOI were associated with changes in fat distribution. Subjects were 126 healthy, premenopausal women, BMI 27–30 kg/m2. They were randomized to one of three groups: diet only, diet + aerobic‐, or diet + resistance training until a BMI <25 kg/m2 was achieved. Fat distribution was measured with computed tomography, and body composition with dual‐energy X‐ray absorptiometry. Serum concentrations of tumor necrosis factor (TNF)‐α, soluble TNF receptor 1 (sTNF‐R1), soluble TNF receptor 2 (sTNF‐R2), C‐reactive protein (CRP), and interleukin (IL)‐6 were assessed. Results of repeated‐measures ANOVA indicated a significant effect of time on MOI, such that MOI decreased with weight loss. Results of mixed‐model analysis indicated that adjusting for intra‐abdominal adipose tissue (IAAT) and total fat mass explained the decreases in TNF‐α and sTNF‐R1, whereas only total fat mass explained the decreases in sTNF‐R2, IL‐6, and CRP. In conclusion, weight loss was associated with decreases in MOI. The effect of weight loss appeared to be mediated by changes in total fat mass or IAAT. Addition of exercise did not alter the response, suggesting that weight loss has a more profound impact for reducing MOI in overweight women than exercise.
Long‐Term Effects of a Multidisciplinary Treatment of Uncomplicated Obesity on Carotid Intima‐Media Thickness
Authors: Buscemi Silvio , Batsis John A. , Verga Salvatore , Carciola Tommasa , Mattina Alessandro , Citarda Salvatore , Re Andrea , Arnone Mariangela , D'Orio Leonardo , Belmonte Serena , D'Angelo Angela , Cerasola Giovanni
Published: December 2010

Obesity is associated with well‐known cardiovascular risk factors and a lower life expectancy. This study investigated whether nonoperative nutritional treatment of obesity without comorbidities influenced the carotid intima‐media thickness (c‐IMT) in the long run. Fifty‐four subjects of an original cohort of 251 subjects were re‐evaluated 10 years after a medical nutritional treatment (MNT) with cognitive‐behavioral approach for uncomplicated obesity. Forty subjects were classified as failure (10‐year body weight change >0.5 kg) and 14 (body weight change ≤0.5 kg) as a success of the MNT. Ten years after MNT, c‐IMT significantly increased (0.06 ± 0.02 mm; P = 0.004) in the failure group and significantly decreased (−0.07 ± 0.03 mm; P = 0.027) in the success group. Ten‐year change in c‐IMT correlated significantly with 10‐year change in body weight (r = 0.28; P = 0.040). Multiple stepwise linear regression analysis demonstrated that age, final BMI, and group (success or failure) influenced independently the 10‐year c‐IMT. In conclusion, this study is in agreement with the possibility that the successful MNT of obesity may be an effective choice in the long run and seems to indicate that it may be able to reduce the cardiovascular risk as reflected by the change in c‐IMT.
Mode bifurcation and fold points of complex dispersion curves for the negative index metamaterial Goubau line
Authors: Overfelt P. L. , Halterman Klaus , Feng Simin , Bowling D. R.
Published: December 2010

In this paper the complex dispersion curves of the four lowest-order transverse magnetic modes of a dielectric Goubau line (ϵ>0,μ>0) are compared with those of a weakly dispersive negative index metamaterial (NIM) Goubau line. The vastly different dispersion curve structure for the NIM Goubau line is characterized by unusual features such as mode bifurcation, complex fold points, both proper and improper complex modes, and merging of complex and real modes.
Minimizing crosstalk in three-axial induction magnetometers
Authors: Grosz Asaf , Paperno Eugene , Amrusi Shai , Szpruch Tal
Published: December 2010

A model for crosstalk in three-axial induction magnetometers has been developed theoretically and verified experimentally. The effect of crosstalk on the magnetometer accuracy has been analyzed. It has been found that the inevitable crosstalk in the transverse coils has two components: one due to the applied magnetic flux and the other due to the secondary flux produced by the electric current in the longitudinal coil. The first component has a constant magnitude. The phase of the second component, relative to the first one, is nearly 180° at low frequencies, 90° at resonance, and 0° at high frequencies. Its magnitude approaches zero at low frequencies, has the maximum at resonance, and then drops off by a factor equal to the coils’ quality factor and approaches the first component value. As a result, the crosstalk due to the applied flux is dominant at low frequencies. At a frequency just below the resonance, the crosstalk is very low, if no magnetic feedback is applied. Just above the resonance, the crosstalk reaches the maximum because of the rapid increase in the secondary flux. Applying a strong enough magnetic feedback nearly flattens the crosstalk amplitude response. However, an undesirable effect of the feedback is that it significantly increases the minimum crosstalk value. A very low crosstalk at a single frequency can be beneficial for magnetometers tuned to a narrow frequency band. It can also be beneficial for wide-band magnetometers to measure their mechanical orthogonality with a minimum effect of crosstalk.
Metastable anions of dinitrobenzene: Resonances for electron attachment and kinetic energy release
Authors: Mauracher A. , Denifl S. , Edtbauer A. , Hager M. , Probst M. , Echt O. , Märk T. D. , Scheier P. , Field T. A. , Graupner K.
Published: December 2010

Attachment of free, low-energy electrons to dinitrobenzene (DNB) in the gas phase leads to DNB− as well as several fragment anions. DNB−, (DNB-H)−, (DNB-NO)−, (DNB-2NO)−, and (DNB-NO2)− are found to undergo metastable (unimolecular) dissociation. A rich pattern of resonances in the yield of these metastable reactions versus electron energy is observed; some resonances are highly isomer-specific. Most metastable reactions are accompanied by large average kinetic energy releases (KER) that range from 0.5 to 1.32 eV, typical of complex rearrangement reactions, but (1,3-DNB-H)− features a resonance with a KER of only 0.06 eV for loss of NO. (1,3-DNB-NO)− offers a rare example of a sequential metastable reaction, namely, loss of NO followed by loss of CO to yield C5H4O− with a large KER of 1.32 eV. The G4(MP2) method is applied to compute adiabatic electron affinities and reaction energies for several of the observed metastable channels.
Distributed energy tapestry for heating the landscape
Authors: Rocha L. A. O. , Lorente S. , Bejan A.
Published: December 2010

Here we show that the production and use of heating on an area must be distributed in clusters organized such that the losses associated with centers of production are balanced by the losses associated with distribution lines. The energy needs increase in time because the population density and the individual need increase. We consider only the increase in the individual need in time. We illustrate the “distributed energy systems” concept with the production and distribution of hot water on an area. Four classes of designs are analyzed and compared: (0) individual, i.e., one water heater for one user, (r) radial, i.e., N users supplied via radial pipes from a central heater, (2) dendritic network constructed by pairing N users around a central heating, and (4) dendritic network constructed by quadrupling the elemental areas occupied by the users. We show that there is an optimal cluster size (N) as a tradeoff between central losses and distributed losses. We also discover that several distinct (abrupt) design “transitions” must exist: the recommended design changes through designs 0, r, 2, and 4, as the amount of water used by each individual increases in time with the standard of living.
Investigation of thermal and electrical conductivity of graphene based nanofluids
Authors: Baby Tessy Theres , Ramaprabhu S
Published: December 2010

We report for the first time, the synthesis of highly stable exfoliated graphene based nanofluids with water and ethylene glycol as base fluids with out any surfactant and the subsequent studies on their thermal and electrical conductivities. Graphene was synthesized by thermal exfoliation of graphene oxide at 1050 °C in Ar atmosphere. The as-synthesized graphene has been suitably functionalized and further dispersed it in the base fluids without any surfactant. Thermal and electrical conductivities of these nanofluids were measured for varying volume fractions and at different temperatures. An enhancement in thermal conductivity by about 14% has been achieved at 25 °C with deionized water (DI) as base fluid at a very low volume fraction of 0.056% which increases to about 64% at 50 °C. Electrical conductivity measurements for these nanofluids indicate an enormous enhancement at 25 °C for a volume fraction of 0.03%in DI water.
From qubits to E7
Authors: Cerchiai Bianca Letizia , van Geemen Bert
Published: December 2010

There is an intriguing relation between quantum information theory and super gravity, discovered by M. J. Duff and S. Ferrara. It relates entanglement measures for qubits to black hole entropy, which in a certain case involves the quartic invariant on the 56-dimensional representation of the Lie group E7. In this paper we recall the relatively straightforward manner in which three-qubits lead to E7, or at least to the Weyl group of E7. We also show how the Fano plane emerges in this context.
Real-time nonlinear correction of back-focal-plane detection in optical tweezers
Authors: Aggarwal Tanuj , Salapaka Murti
Published: December 2010

Photodiode based detection of laser trapped beads using forward scattered light is a frequently employed technique for position measurement. There is a nonlinear relationship between photodiode outputs and bead position but for small displacements linear approximation holds well. Traditionally, the nonlinearity is compensated by normalizing the photodiode's position signal with the intensity signal and then using a polynomial fit in the range where voltage to position mapping is one to one. In this article, this range is extended by using the intensity signal as an independent input along with the two position signals. A map from the input signals to the actual position values is obtained. This mapping is one-to-one for a larger range that results in an increased detection range. An artificial neural network that facilitates implementation is employed for this purpose. This scheme is implemented on a Field Programmable Gate Array based data acquisition and control hardware with closed loop bandwidth of 50 kHz. Detection of the order of 350 nm from the center of detection laser is demonstrated for a 500 nm diameter bead compared to 180 nm achieved by a polynomial fit.
A high-pressure cell for kinetic studies on gas hydrates by powder x-ray diffraction
Authors: Luzi Manja , Girod Matthias , Naumann Rudolf , Schicks Judith M. , Erzinger Jörg
Published: December 2010

A new high-pressure–low-temperature cell was developed for in situ observations of gas hydrates by powder x-ray diffraction. The experimental setup allows investigating hydrate formation and dissociation as well as transformation processes between different hydrate crystal structures as a function of pressure, temperature, and feed gas composition. Due to a continuous gas flow, the composition of the gas phase is kept constant during the whole experiment. This is crucial for the formation of mixed hydrates formed from feed gas mixtures that contain one or more components in low concentrations. The pressure cell can be used in a pressure range between 0.1 and 4.0 MPa and a temperature range between 248 and 298 K. First results of time-resolved measurements of a mixed structure II CH4 + iso-C4H10 hydrate and a structure I CO2 hydrate are presented.
Interplay between metal nanoparticles and dielectric spacing layers during the growth of Au/Si3N4 multilayers
Authors: Céspedes E. , Toudert J. , de Sousa Meneses D. , Prieto C. , Traverse A.
Published: December 2010

Competition between ordering and disordering processes during growth of granular Si3N4/[Au(t)/Si3N4]n thin films by vapor deposition is tracked in a simple, unconventional and nondestructive way by probing the infrared response of the dielectric matrix. Si3N4 crystallization occurs as a consequence of the presence of Au nanostructures. The average Si3N4 crystalline order is improved upon increasing the thickness tAu of deposited Au per bilayer. On the contrary, crystalline order is destroyed when the number n of bilayers overcomes a threshold value that varies with t. Additional information provided by conventional measurements (x-ray diffraction, visible absorption spectroscopy) and by transmission electron microscopy observations suggests that the Si3N4 atomic ordering results from seed-induced crystallization on the Au(111) planes. Disordering is tentatively attributed to roughness accumulation upon stacking, whose magnitude is ruled by the roughness of the first deposited Au granular layer.
Nonlocal van der Waals density functional: The simpler the better
Authors: Vydrov Oleg A. , Van Voorhis Troy
Published: December 2010

We devise a nonlocal correlation energy functional that describes the entire range of dispersion interactions in a seamless fashion using only the electron density as input. The new functional is considerably simpler than its predecessors of a similar type. The functional has a tractable and robust analytic form that lends itself to efficient self-consistent implementation. When paired with an appropriate exchange functional, our nonlocal correlation model yields accurate interaction energies of weakly-bound complexes, not only near the energy minima but also far from equilibrium. Our model exhibits an outstanding precision at predicting equilibrium intermonomer separations in van der Waals complexes. It also gives accurate covalent bond lengths and atomization energies. Hence the functional proposed in this work is a computationally inexpensive electronic structure tool of broad applicability.
Effective local potentials for excited states
Authors: Staroverov Viktor N. , Glushkov Vitaly N.
Published: December 2010

The constrained variational Hartree–Fock method for excited states of the same symmetry as the ground state [Chem. Phys. Lett. 287, 189 (1998)] is combined with the effective local potential (ELP) method [J. Chem. Phys. 125, 081104 (2006)] to generate Kohn–Sham-type exact-exchange potentials for singly excited states of many-electron systems. Illustrative examples include the three lowest \documentclass[12pt]{minimal}\begin{document}$^{2}S$\end{document}2S states of the Li and Na atoms and the three lowest \documentclass[12pt]{minimal}\begin{document}$^{3}S$\end{document}3S states of He and Be. For the systems studied, excited-state ELPs differ from the corresponding ground-state potentials in two respects: They are less negative and have small additional “bumps” in the outer electron region. The technique is general and can be used to approximate excited-state exchange-correlation potentials for other orbital-dependent functionals.
Trapped gyro-Landau-fluid transport modeling of DIII-D hybrid discharges
Authors: Kinsey J. E. , Staebler G. M. , Petty C. C.
Published: December 2010

Previous work has summarized the physics and first results of benchmarking the trapped gyro-Landau-fluid (TGLF) model for turbulent transport driven by trapped ion and electron modes, ion and electron temperature gradient (ETG) modes, and electromagnetic kinetic ballooning modes including the effects of shaped geometry. Recently, an improved collision model was implemented which provides a more accurate fit to a transport database of nonlinear collisional GYRO [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] simulations of long wavelength driftwave turbulence. The impact of the new collision model on TGLF modeling results was unknown. Using the improved TGLF model we obtain excellent agreement with the ion and electron temperature profiles from 30 DIII-D [A. Mahdavi and J. L. Luxon, Fusion Sci. Technol. 48, 2 (2005)] hybrid discharges. The transport results show that the electron energy transport tends to be dominated by short wavelength ETG modes in cases where the ion energy transport approaches neoclassical levels. The hybrid regime has significant energy confinement improvement from E×B velocity shear which is well predicted by TGLF. Weak magnetic shear and low safety factor are also shown to enhance the hybrid regime energy confinement. In high normalized β hybrids, we find that finite β effects noticably reduce the predicted electron energy transport and improve agreement with the measured electron temperature profiles.
Robust synchronization of a class of uncertain chaotic systems based on quadratic optimal theory and adaptive strategy
Authors: Ataei Mohammad , Iromloozadeh Armin , Karimi Bahram
Published: December 2010

This paper presents a chaos synchronization method for a class of uncertain chaotic systems using the combination of an optimal control theory and an adaptive strategy. A quadratic optimal regulator and an adaptive control are used to represent the controller’s structure. The asymptotic stability of the corresponding error dynamical system is guaranteed through Lyapunov stability analysis. The proposed controller is employed in two uncertain chaotic Lu systems, and their promising performances are illustrated.
Sampling rare events in nonequilibrium and nonstationary systems
Authors: Berryman Joshua T. , Schilling Tanja
Published: December 2010

Although many computational methods for rare event sampling exist, this type of calculation is not usually practical for general nonequilibrium conditions, with macroscopically irreversible dynamics and away from both stationary and metastable states. A novel method for calculating the time-series of the probability of a rare event is presented which is designed for these conditions. The method is validated for the cases of the Glauber–Ising model under time-varying shear flow, the Kawasaki–Ising model after a quench into the region between nucleation dominated and spinodal decomposition dominated phase change dynamics, and the parallel open asymmetric exclusion process. The method requires a subdivision of the phase space of the system: it is benchmarked and found to scale well for increasingly fine subdivisions, meaning that it can be applied without detailed foreknowledge of the physically important reaction pathways.
The U(1)-Kepler Problems
Authors: Meng Guowu
Published: December 2010

Let n ⩾ 2 be a positive integer. To each irreducible representation σ of U(1), a U(1)-Kepler problem in dimension (2n − 1) is constructed and analyzed. This system is superintegrable and when n = 2 it is equivalent to a MICZ-Kepler problem. The dynamical symmetry group of this system is \documentclass[12pt]{minimal}\begin{document}$\widetilde{\rm U}(n, n)$\end{document}Ũ(n,n), and the Hilbert space of bound states \documentclass[12pt]{minimal}\begin{document}${\mathscr{H}}(\sigma )$\end{document}H(σ) is the unitary highest weight representation of \documentclass[12pt]{minimal}\begin{document}$\widetilde{\rm U}(n, n)$\end{document}Ũ(n,n) with the minimal positive Gelfand-Kirillov dimension. Furthermore, it is shown that the correspondence between \documentclass[12pt]{minimal}\begin{document}$\sigma ^*$\end{document}σ* (the dual of σ) and \documentclass[12pt]{minimal}\begin{document}$\mathscr{H}(\sigma )$\end{document}H(σ) is the theta-correspondence for dual pair \documentclass[12pt]{minimal}\begin{document}$(\mathrm{U}(1), {\rm U}(n,n))\subseteq \mathrm{Sp}_{4n}({\bb R})$\end{document}(U(1),U(n,n))⊆ Sp 4n(R).
Experimental study of dispersion and miscible viscous fingering of initially circular samples in Hele-Shaw cells
Authors: Maes R. , Rousseaux G. , Scheid B. , Mishra M. , Colinet P. , De Wit A.
Published: December 2010

Experimental studies are conducted to analyze dispersion and miscible viscous fingering of initially circular samples of a given solution displaced linearly at constant speed U by another solution in horizontal Hele-Shaw cells (two glass plates separated by a thin gap). In the stable case of a dyed water sample having the same viscosity as that of displacing nondyed water, we analyze the transition between dispersive and advective transport of the passive scalar displaced linearly. At low displacement speed and after a certain time, the length of the sample increases as a square root of time allowing to compute the value of a dispersion coefficient. At larger injection speed, the displacement remains advective for the duration of the experiment, with a length of the sample increasing linearly in time. A parametric study allows to gain insight into the switch from one regime to another as a function of the gap width of the cell. In the unstable case of viscous glycerol samples displaced by dyed water, the rear interface of the sample where less viscous water pushes more viscous glycerol is unstable with regard to viscous fingering. The interface deforms into fingers, the number and size of which depend on the viscosity ratio between the two solutions and on the displacement speed. We study the influence of these viscous fingering phenomena on the increased spreading of the sample for various mobility ratios and injection speeds.
Monopolelike probes for quantitative magnetic force microscopy: Calibration and application
Authors: Vock S. , Wolny F. , Mühl T. , Kaltofen R. , Schultz L. , Büchner B. , Hassel C. , Lindner J. , Neu V.
Published: December 2010

A local magnetization measurement was performed by magnetic force microscopy (MFM) to determine magnetization in domains of an exchange coupled [Co/Pt]/Co/Ru multilayer with predominant perpendicular anisotropy. The quantitative MFM measurements were conducted with an iron-filled carbon nanotube tip, which is shown to behave like a monopole. As a result we determined an additional in-plane magnetization component of the multilayer, which is explained by estimating the effective permeability of the sample within the μ∗-method.
The impact of uncertainty on shape optimization of idealized bypass graft models in unsteady flow
Authors: Sankaran Sethuraman , Marsden Alison L.
Published: December 2010

It is well known that the fluid mechanics of bypass grafts impacts biomechanical responses and is linked to intimal thickening and plaque deposition on the vessel wall. In spite of this, quantitative information about the fluid mechanics is not currently incorporated into surgical planning and bypass graft design. In this work, we use a derivative-free optimization technique for performing systematic design of bypass grafts. The optimization method is coupled to a three-dimensional pulsatile Navier–Stokes solver. We systematically account for inevitable uncertainties that arise in cardiovascular simulations, owing to noise in medical image data, variable physiologic conditions, and surgical implementation. Uncertainties in the simulation input parameters as well as shape design variables are accounted for using the adaptive stochastic collocation technique. The derivative-free optimization framework is coupled with a stochastic response surface technique to make the problem computationally tractable. Two idealized numerical examples, an end-to-side anastomosis, and a bypass graft around a stenosis, demonstrate that accounting for uncertainty significantly changes the optimal graft design. Results show that small changes in the design variables from their optimal values should be accounted for in surgical planning. Changes in the downstream (distal) graft angle resulted in greater sensitivity of the wall-shear stress compared to changes in the upstream (proximal) angle. The impact of cost function choice on the optimal solution was explored. Additionally, this work represents the first use of the stochastic surrogate management framework method for robust shape optimization in a fully three-dimensional unsteady Navier–Stokes design problem.
In-depth analysis of the CuIn1−xGaxSe2 film for solar cells, structural and optical characterization
Authors: Slobodskyy A. , Slobodskyy T. , Ulyanenkova T. , Doyle S. , Powalla M. , Baumbach T. , Lemmer U.
Published: December 2010

Space-resolved x-ray diffraction measurements of gradient-etched CuIn1−xGaxSe2 (CIGS) solar cells provide information about stress and texture depth profiles in the absorber layer. An important parameter of CIGS layer growth dynamics, the absorber thickness-dependent stress in the molybdenum back contact, is analyzed. Texturing of grains and quality of the polycrystalline absorber layer are correlated with the intentional composition gradients (band gap grading). The band gap gradient is determined by space-resolved photoluminescence measurements and correlated with composition and strain profiles.
Gigantic enhancement of spin Seebeck effect by phonon drag
Authors: Adachi Hiroto , Uchida Ken-ichi , Saitoh Eiji , Ohe Jun-ichiro , Takahashi Saburo , Maekawa Sadamichi
Published: December 2010

We investigate both theoretically and experimentally a gigantic enhancement of the spin Seebeck effect in a prototypical magnet LaY2Fe5O12 at low temperatures. Our theoretical analysis sheds light on the important role of phonons; the spin Seebeck effect is enormously enhanced by nonequilibrium phonons that drag the low-lying spin excitations. We further argue that this scenario gives a clue to understand the observation of the spin Seebeck effect that is unaccompanied by a global spin current, and predict that the substrate condition affects the observed signal.