bluuebunny/crossref_metadata_2025 huggingface dataset:
In situ measurements of volatile organic compounds in a boreal forest
Authors: Hakola H. , Hellén H. , Hemmilä M. , Rinne J. , Kulmala M.
Published: December 2012

Abstract. We present biogenic VOC, including sesquiterpenes, measurements at the SMEAR II station (Station For Measuring Forest Ecosystem-Atmosphere Relations) in Finland using an in situ gas chromatograph mass-spectrometer with 2 h time resolution. The measurements were conducted over the period October 2010–October 2011, at least one week every month. To our knowledge there are no earlier species-speciated semi-continuous BVOC data also covering dormant periods. This was also the first time sesquiterpene mixing ratios were measured in a boreal forest. During the winter months, and still in March, the mixing ratios of all biogenic compounds were very low, most of the time below detection limits. The monoterpene mixing ratios increased in April and started to show diurnal variability, with maximum mixing ratio at night and minima during the day. The diurnal variability continued until October, after which the mixing ratios decreased and then only occasional episodes took place. The diurnal variation was affected by boundary layer height. Sesquiterpene mixing ratios were very low, only a few ppt. The main sesquiterpenes were longifolene and isolongifolene. The diurnal variation of isoprene was opposite to the mono- and sesquiterpene diurnal curve due to isoprene's light dependent emissions. Due to its daytime maximum mixing ratios, isoprene also dominated hydroxyl radical reactivity in summer even though our isoprene measurements are underestimates due to a breakthrough in a cold trap.
Top-down estimate of surface flux in the Los Angeles Basin using a mesoscale inverse modeling technique: assessing anthropogenic emissions of CO, NOx and CO2 and their impacts
Authors: Brioude J. , Angevine W. M. , Ahmadov R. , Kim S.-W. , Evan S. , McKeen S. A. , Hsie E.-Y. , Frost G. J. , Neuman J. A. , Pollack I. B. , Peischl J. , Ryerson T. B. , Holloway J. , Brown S. S. , Nowak J. B. , Roberts J. M. , Wofsy S. C. , Santoni G. W. , Trainer M.
Published: December 2012

Abstract. We present top-down estimates of anthropogenic CO, NOx and CO2 surface fluxes at mesoscale using a Lagrangian model in combination with three different WRF model configurations, driven by data from aircraft flights during the CALNEX campaign in southern California in May–June 2010. The US EPA National Emission Inventory 2005 (NEI 2005) was the prior in the CO and NOx inversion calculations. The flux ratio inversion method, based on linear relationships between chemical species, was used to calculate the CO2 inventory without prior knowledge of CO2 surface fluxes. The inversion was applied to each flight to estimate the variability of single-flight-based flux estimates. In Los Angeles (LA) County, the uncertainties on CO and NOx fluxes were 10% and 15%, respectively. Compared with NEI 2005, the CO posterior emissions were lower by 43% ± 6% in LA County and by 37% ± 10% in the South Coast Air Basin (SoCAB). NOx posterior emissions were lower by 32% ± 10% in LA County and by 27% ± 15% in the SoCAB. NOx posterior emissions were 40% lower on weekends relative to weekdays. The CO2 posterior estimates were 183 ± 18 Tg yr−1 in SoCAB. A flight during ITCT in 2002 was used to estimate emissions in the LA Basin in 2002. From 2002 to 2010, the CO and NOx posterior emissions decreased by 41% and 37%, respectively, in agreement with previous studies. Over the same time period, CO2 emissions increased by 10% ± 14% in LA County but decreased by 4% ± 10% in the SoCAB, a statistically insignificant change. Overall, the posterior estimates were in good agreement with the California Air Resources Board (CARB) inventory, with differences of 15% or less. However, the posterior spatial distribution in the basin was significantly different from CARB for NOx emissions. WRF-Chem mesoscale chemical-transport model simulations allowed an evaluation of differences in chemistry using different inventory assumptions, including NEI 2005, CARB 2010 and the posterior inventories derived in this study. The biases in WRF-Chem ozone were reduced and correlations were increased using the posterior from this study compared with simulations with the two bottom-up inventories, showing that improving the spatial distribution of ozone precursor surface emissions is also important in mesoscale chemistry forecasts.
Internal respiration of Amazon tree stems greatly exceeds external CO2 efflux
Authors: Angert A. , Muhr J. , Negron Juarez R. , Alegria Muñoz W. , Kraemer G. , Ramirez Santillan J. , Barkan E. , Mazeh S. , Chambers J. Q. , Trumbore S. E.
Published: December 2012

Abstract. Respiration in tree stems is an important component of forest carbon balance. The rate of CO2 efflux from the stem has often been assumed to be a measure of stem respiration. However, recent work in temperate forests has demonstrated that stem CO2 efflux can either overestimate or underestimate respiration rate because of emission or removal of CO2 by transport in xylem water. Here, we studied gas exchange from stems of tropical forest trees using a new approach to better understand respiration in an ecosystem that plays a key role in the global carbon cycle. Our main questions were (1) is internal CO2 transport important in tropical trees, and, if so, (2) does this transport result in net release of CO2 respired in the roots at the stem, or does it cause the opposite effect of net removal of stem-respired CO2? To answer these questions, we measured the ratio of stem CO2 efflux to O2 influx. This ratio, defined here as apparent respiratory quotient (ARQ), is expected to equal 1.0 if carbohydrates are the substrate for respiration, and the net transport of CO2 in the xylem water is negligible. Using a stem chamber approach to quantifying ARQ, we found values of 0.66 ± 0.18. These low ARQ values indicate that a large portion of respired CO2 (~ 35%) is not emitted locally, and is probably transported upward in the stem. ARQ values of 0.21 ± 0.10 were found for the steady-state gas concentration within the stem, sampled by in-stem equilibration probes. These lower values may result from the proximity to the xylem water stream. In contrast, we found ARQ values of 1.00 ± 0.13 for soil respiration. Our results indicate the existence of a considerable internal flux of CO2 in the stems of tropical trees. If the transported CO2 is used in the canopy as a substrate for photosynthesis, it could account for up to 10% of the C fixed by the tree, and perhaps serve as a mechanism that buffers the response of the tree to changing CO2 levels. Our results also indicate, in agreement with previous work, that the widely used CO2 efflux approach for determining stem respiration is unreliable. We demonstrate here a field applicable approach for measuring the O2 uptake rate, which we suggest to be a more appropriate method to estimate stem respiration rates.
Annual carbon balance of a peatland 10 yr following restoration
Authors: Strack M. , Zuback Y. C. A.
Published: December 2012

Abstract. Undisturbed peatlands represent long term net sinks of carbon; however, peat extraction converts these systems into large and persistent sources of greenhouse gases. Although rewetting and restoration following peat extraction have taken place over the last several decades, very few studies have investigated the longer term impact of this restoration on peatland carbon balance. We determined the annual carbon balance of a former horticulturally-extracted peatland restored 10 yr prior to the study and compared these values to the carbon balance measured at neighboring unrestored and natural sites. Carbon dioxide (CO2) and methane (CH4) fluxes were measured using the chamber technique biweekly during the growing season from May to October 2010 and three times over the winter period. Dissolved organic carbon (DOC) export was measured from remnant ditches in the unrestored and restored sites. During the growing season the restored site had greater uptake of CO2 than the natural site when photon flux density was greater than 1000 µmol m−2 s−1, while the unrestored site remained a source of CO2. Ecosystem respiration was similar between natural and restored sites, which were both significantly lower than the unrestored site. Methane flux remained low at the restored site except from open water pools, created as part of restoration, and remnant ditches. Export of DOC during the growing season was 5.0 and 28.8 g m−2 from the restored and unrestored sites, respectively. Due to dry conditions during the study year all sites acted as net carbon sources with annual balance of the natural, restored and unrestored sites of 250.7, 148.0 and 546.6 g C m−2, respectively. Although hydrological conditions and vegetation community at the restored site remained intermediate between natural and unrestored conditions, the site acted as a smaller source of carbon than the natural peatland suggesting that near natural carbon balance can be returned ~ 10 yr post-restoration.
Seasonal variations of viral- and nanoflagellate-mediated mortality of heterotrophic bacteria in the coastal ecosystem of subtropical Western Pacific
Authors: Tsai A.-Y. , Gong G.-C. , Hung J.
Published: December 2012

Abstract. Since viral lysis and nanoflagellate grazing differ in their impact on the aquatic food web, it is important to assess the relative importance of both bacterial mortality factors. In this study, an adapted version of the modified dilution method was applied to simultaneously estimate the impact of both viral and nanoflagellate grazing on the mortality of heterotrophic bacteria. A series of experiments was conducted monthly from April to December 2011 and April to October 2012. The growth rates of bacteria we measured ranged from 0.078 h−1 (April 2011) to 0.42 h−1 (September 2011), indicating that temperature can be important in controlling the seasonal variations of bacterial growth. Furthermore, it appeared that seasonal changes in nanoflagellate grazing and viral lysis could account for 34% to 68% and 13% to 138% of the daily removal of bacterial production, respectively. We suggest that nanoflagellates grazing might play a key role in controlling bacterial biomass and might exceed the impact of viral lysis during the summer period (July to August), because of the higher abundance of nanoflagellates at that time. Viral lysis, on the other hand, was identified as the main cause of bacterial mortality between September and December. Based on these findings in this study, the seasonal variations in bacterial abundance we observed can be explained by a scenario in which both growth rates and loss rates (grazing + viral lysis) influence the dynamics of the bacteria community.
Vegetation dynamics in the Northeastern Mediterranean region during the past 23 000 yr: insights from a new pollen record from the Sea of Marmara
Authors: Valsecchi V. , Sanchez Goñi M. F. , Londeix L.
Published: December 2012

Abstract. High-resolution pollen analysis of core MD01-2430 from the Sea of Marmara (40°47.81' N, 27°43.51' E) allows us to reconstruct the vegetation response to climatic changes during the past 23 cal ka in the Northeastern Mediterranean. Variation in mesic/temperate forest cover indicates major climatic shifts connected to Heinrich Stadial 1, Bölling-Allerød, Younger Dryas and to the onset of the Holocene. Pollen–anthropogenic indicator approach was used to recognize human-induced landscape changes in the Sea of Marmara. The pollen-inferred onset of the Holocene occurs at ca. 11.5 cal ka, indicating that the Northeastern Mediterranean region represents a transitional zone where higher moisture availability supported an earlier forest expansion than the borderlands of the Aegean Sea and Black Sea. Two major forest retreats occurred during the Holocene at ca. 5.5 and 2.1 cal ka. The Holocene forest setbacks are in phase with previously published alkenone-inferred sea-surface temperature decreases in the Sea of Marmara reconstructed from the same core. Our new pollen record testifies the sensitivity of Mediterranean forests to changes in moisture availability, which is driven by changes in high-latitude atmospheric processes (North Atlantic Oscillations and/or Siberian High).
Multi-site calibration, validation, and sensitivity analysis of the MIKE SHE Model for a large watershed in northern China
Authors: Wang S. , Zhang Z. , Sun G. , Strauss P. , Guo J. , Tang Y. , Yao A.
Published: December 2012

Abstract. Model calibration is essential for hydrologic modeling of large watersheds in a heterogeneous mountain environment. Little guidance is available for model calibration protocols for distributed models that aim at capturing the spatial variability of hydrologic processes. This study used the physically-based distributed hydrologic model, MIKE SHE, to contrast a lumped calibration protocol that used streamflow measured at one single watershed outlet to a multi-site calibration method which employed streamflow measurements at three stations within the large Chaohe River basin in northern China. Simulation results showed that the single-site calibrated model was able to sufficiently simulate the hydrographs for two of the three stations (Nash-Sutcliffe coefficient of 0.65–0.75, and correlation coefficient 0.81–0.87 during the testing period), but the model performed poorly for the third station (Nash-Sutcliffe coefficient only 0.44). Sensitivity analysis suggested that streamflow of upstream area of the watershed was dominated by slow groundwater, whilst streamflow of middle- and down- stream areas by relatively quick interflow. Therefore, a multi-site calibration protocol was deemed necessary. Due to the potential errors and uncertainties with respect to the representation of spatial variability, performance measures from the multi-site calibration protocol slightly decreased for two of the three stations, whereas it was improved greatly for the third station. We concluded that multi-site calibration protocol reached a compromise in term of model performance for the three stations, reasonably representing the hydrographs of all three stations with Nash-Sutcliffe coefficient ranging from 0.59–072. The multi-site calibration protocol applied in the analysis generally has advantages to the single site calibration protocol.
Ikaite crystal distribution in Arctic winter sea ice and implications for CO2 system dynamics
Authors: Rysgaard S. , Søgaard D. H. , Cooper M. , Pućko M. , Lennert K. , Papakyriakou T. N. , Wang F. , Geilfus N. X. , Glud R. N. , Ehn J. , McGinnnis D. F. , Attard K. , Sievers J. , Deming J. W. , Barber D.
Published: December 2012

Abstract. The precipitation of ikaite (CaCO3·6H2O) in polar sea ice is critical to the efficiency of the sea ice-driven carbon pump and potentially important to the global carbon cycle, yet the spatial and temporal occurrence of ikaite within the ice is poorly known. We report unique observations of ikaite in unmelted ice and vertical profiles of ikaite abundance and concentration in sea ice for the crucial season of winter. Ice was examined from two locations: a 1 m thick land-fast ice site and a 0.3 m thick polynya site, both in the Young Sound area (74° N, 20° W) of NE Greenland. Ikaite crystals, ranging in size from a few µm to 700 µm were observed to concentrate in the interstices between the ice platelets in both granular and columnar sea ice. In vertical sea-ice profiles from both locations, ikaite concentration determined from image analysis, decreased with depth from surfaceice values of 700–900 µmol kg−1 ice (~ 25 × 106 crystals kg−1) to bottom-layer values of 100–200 µmol kg−1 ice (1–7 × 106 kg−1), all of which are much higher (4–10 times) than those reported in the few previous studies. Direct measurements of total alkalinity (TA) in surface layers fell within the same range as ikaite concentration whereas TA concentrations in bottom layers were twice as high. This depth-related discrepancy suggests interior ice processes where ikaite crystals form in surface sea ice layers and partly dissolved in bottom layers. From these findings and model calculations we relate sea ice formation and melt to observed pCO2 conditions in polar surface waters, and hence, the air-sea CO2 flux.
Hindcasting to measure ice sheet model sensitivity to initial states
Authors: Aschwanden A. , Aðalgeirsdóttir G. , Khroulev C.
Published: December 2012

Abstract. Recent observations of the Greenland ice sheet indicate rapid mass loss at an accelerating rate with an increasing contribution to global mean sea level. Ice sheet models are used for projections of such future contributions of ice sheets to sea level, but the quality of projections is difficult to measure directly. Realistic initial states are crucial for accurate simulations. To test initial states we use hindcasting, i.e. forcing a model with known or closely-estimated inputs for past events to see how well the output matches observations. By simulating the recent past of Greenland, and comparing to observations of ice thickness, ice discharge, surface speeds, mass loss and surface elevation changes for validation, we find that the short term model response is strongly influenced by the initial state. We show that the dynamical state can be mis-represented despite a good agreement with some observations, stressing the importance of using multiple observations. Some initial states generate good agreement with measured mass time series in the hindcast period, and good agreement with present-day kinematic fields. We suggest hindcasting as a methodology for careful validation of initial states that can be done before making projections on decadal to century time-scales.
A Novel Device to Measure Acetabular Inclination with Patients in Lateral Decubitus
Authors: Sykes Alice M. , Hill Janet C. , Beverland David E. , Orr John F.
Published: December 2012

The ability to measure acetabular cup orientation accurately during total hip arthroplasty represents a significant challenge. The aim of this research was to develop and evaluate a novel low cost mechanical device for measuring operative acetabular inclination. Cup implantation was simulated in two trials using the novel device: firstly involving surgeons and engineers orientating acetabular cups with sawbone pelves at a range of inclination angles (20°-55° in 5° increments); secondly in a simulated intra-operative scenario with surgeons. Target angles were compared with achieved angles and deviations from desired angles were recorded. In addition, all participants orientated cups under the same conditions using two other techniques: freehand and with a propriatory Mechanical Alignment Guide. In the first trial, the mean errors (deviations) using freehand technique, the mechanical alignment guide and the new device were 5.2° +/- 4.3° (range 0.1–22.0), 3.6° +/- 3.9° (range 0.1°–33.6°) and 0.5° +/- 0.4° (range 0.0–1.9) respectively. In the second trial, the mean error for freehand technique, mechanical alignment guide and the new device were 6.2° +/- 4.2° (range 0.2–18.2), 3.8° +/- 3.3° (range 0.0–19.1) and 0.6° +/- 0.5° (range 0.0–1.8) respectively. The new device has the potential to allow the surgeon to choose and record operative inclination accurately during total hip arthroplasty in the lateral decubitus position.
Design of Porous Three-Dimensional PDLLA/nano-hap Composite Scaffolds Using Stereolithography
Authors: Ronca Alfredo , Ambrosio Luigi , Grijpma Dirk W.
Published: December 2012

Purpose

The stereolithography process is based on the photopolymerization through a dynamic mask generator of successive layers of photocurable resin, allowing the manufactory of accurate micro objects with high aspect ratio and curved surfaces. In the present work the stereolithography technique is applied to produce nanocomposite bioactive scaffolds from Computer Assisted Design (CAD) files.

Methods

Porous scaffolds are designed with computer software and built with a composite poly(D,L-lactide)/nano hydroxyapatite based resin. Triply-periodic minimal surfaces are shown to be a more versatile source of biomorphic scaffold designs and scaffolds with Double Gyroid architecture are realized and characterized from morphological, mechanical and biological point of view.

Results

The structures show excellent reproduction of the design and good mechanical properties. Human marrow mesenchimal cells (hMSC) are seeded onto porous PDLLA composites for 3 weeks and cultured in osteogenic medium. Presence of nano-hap seems to increase the mechanical properties without affecting the morphology of the structures. The composite Double Gyroid scaffolds exhibit good biocompatibility and confirm that nano-hap enhances the scaffold bioactive and os-teoconductive potential.

Conclusion

The presented technology and materials enable an accurate preparation of tissue engineering composite scaffolds with a large freedom of design, and really complex internal architectures. Results indicate that the scaffolds fulfill the basic requirements of bone tissue engineering scaffold, and have the potential to be applied in orthopedic surgery.
Biliary Atresia: 50 Years after the First Kasai
Authors: Wildhaber Barbara E.
Published: December 2012

Biliary atresia is a rare neonatal disease of unknown etiology, where obstruction of the biliary tree causes severe cholestasis, leading to biliary cirrhosis and death in the first years of life, if the condition is left untreated. Biliary atresia is the most frequent surgical cause of cholestatic jaundice in neonates and should be evoked whenever this clinical sign is associated with pale stools and hepatomegaly. The treatment of biliary atresia is surgical and currently recommended as a sequence of, eventually, two interventions. During the first months of life a hepatoportoenterostomy (a “Kasai,” modifications of which are discussed in this paper) should be performed, in order to restore the biliary flow to the intestine and lessen further damage to the liver. If this fails and/or the disease progresses towards biliary cirrhosis and life-threatening complications, then liver transplantation is indicated, for which biliary atresia represents the most frequent pediatric indication. Of importance, the earlier the Kasai is performed, the later a liver transplantation is usually needed. This warrants a great degree of awareness of biliary atresia, and the implementation of systematic screening for this life-threatening pathology.
Conjugate Effects of Radiation Flux on Double Diffusive MHD Free Convection Flow of a Nanofluid over a Power Law Stretching Sheet
Authors: Anwar Muhammad Imran , Shafie Sharidan , Khan Ilyas , Salleh Mohd Zuki
Published: December 2012

This study theoretically investigates the conjugate effects of radiation flux and magnetohydrodynamic (MHD) on free convection boundary layer flow of a nanofluid over a nonlinear stretching sheet. It is assumed that the magnetic Reynolds number is small enough and the sheet is stretched with a power law velocity under the effects of the magnetic field, the buoyancy parameter, and the solutal buoyancy parameter. The model used for the nanofluid incorporates the effects of Rosseland approximation, Brownian motion, and thermophoresis parameters. By using appropriate similarity transformations, the governing nonlinear partial differential equations are transformed into dimensionless form and numerically solved using an implicit finite difference scheme known as the Keller-box method. It is found that the variations of magnetic field, buoyancy parameter, solutal buoyancy parameter, and the power law velocity parameter have strong influence on the motion.
A Kinetic Study of the Emerging of Grains and Block of Grains from the Inner Volume to the Free Surface of a Cd-Zn Alloy Superplastically Deformed
Authors: Montemayor-Aldrete J. A. , Mendez-Olvera R. , Ugalde-Velez P. , Torres-Villaseñor G. , del Castillo-Mussot M.
Published: December 2012

A local measurement technique for the study of the kinetic processes of emerging of grains or blocks of grains from the inner volume to the free surface of superplastic materials during deformation is presented and used for the case of the Cd-Zn eutectic alloy deformed at room temperature. This technique could be used to evaluate the approximate time of fracture due to fissure or cavitation growth in samples under superplastic deformation. In principle, this technique will be useful for the development of physical procedures, which allows retarding the process of formation of low mismatch angle, , between neighboring grains, process which gives place to blocks of grains which dynamically behave as units under the shear stress action. For materials with nanocrystalline structures, such processes are expected to be higher than those of the case of microcrystalline materials.
Robust Numerical Methods for Singularly Perturbed Differential Equations: A Survey Covering 2008–2012
Authors: Roos Hans-Görg
Published: December 2012

We present new results in the numerical analysis of singularly perturbed convection-diffusion-reaction problems that have appeared in the last five years. Mainly discussing layer-adapted meshes, we present also a survey on stabilization methods, adaptive methods, and on systems of singularly perturbed equations.
Triggering Risk Factors of the Burnout Syndrome in Ob/Gyn Physicians from a Reference Public University of Brazil
Authors: Ferreira Bortoletti Fátima , Teresa Benevides-Pereira Ana Maria , Vasconcellos Esdras Guerreiro , Siqueira José Oliveira , Araujo Júnior Edward , Nardozza Luciano Marcondes Machado , Sebastiani Ricardo Werner , Moron Antonio Fernandes
Published: December 2012

Objective. To identify the risk factors to the development of Burnout Syndrome in Ob/Gyn Brazilian physicians in four dimensions: emotional exhaustion (EE), professional repression (PR), dehumanization (De), and emotional distancing (EmD). Methods. A prospective cross-sectional study was realized with 48 Ob/Gyn physicians (12 lecturers, 12 attending physicians, 12 medical residents, and 12 graduate students) from Department of Obstetrics, São Paulo Federal University (UNIFESP). We used a sociodemographic questionnaire focusing on the activities (administrative, educational, healthcare, and research). We applied a Burnout Syndrome Inventory (BSI) composed of two parts: triggering factors (ISB1) and the Burnout Syndrome (ISB2). The ISB1 is composed of two scales: positive organizational conditions (POC) and negative organizational conditions (NOC). The ISB2 is composed of four scales: EE, PR, De, and EmD. Results. We observed a rate below and above average to POC and NOC, respectively. The dimensions recorded a level above average to EE, an index at the upper limit of the average to De, a median index to EmD, and a median index to PR. Conclusions. The Ob/Gyn physicians are in an area of vulnerability for the development of Burnout Syndrome due to the high level of EE and De, associated with a median index of PR. The high rate of NOC contributes to the triggering of this scenery.
Evaluation of Acute Locoregional Toxicity in Patients with Breast Cancer Treated with Adjuvant Radiotherapy in Combination with Pazopanib
Authors: Goyal Sharad , Shah Sneha , Khan Atif J. , Danish Hasan , Haffty Bruce G.
Published: December 2012

Purpose. The purpose of this study was to analyze acute locoregional toxicity in patients with breast cancer receiving concurrent pazopanib and RT. Materials and Methods. Patients with breast cancer who received pazopanib in combination with radiation were identified and matched (2 : 1) to patients with breast cancer who did not receive pazopanib by use of chemotherapy, radiation field design, and radiation dose. Toxicity was scored by the Common Terminology Criteria for Adverse Events and statistical analysis was performed. Results. Grade 1 or 2 radiation dermatitis was seen in 100% and 84% of pazopanib and RT patients and matched controls respectively (P = NS). None of the patients receiving pazopanib and RT experienced ≥ grade 3 toxicity within the irradiated volume; three (16%) matched patients experienced a grade 3 skin reaction (P = 0.05). Interestingly, grade 1 or 2 hyperpigmentation was seen in 17% of pazopanib and RT patients and 60% of matched controls (P = 0.005). Conclusion. The addition of concurrent pazopanib and RT when treating the intact breast, chest wall, and associated nodal regions in breast cancer seems to be safe and well tolerated.
Evaluation of the Periodontal Status in Acromegalic Patients: A Comparative Study
Authors: Harb Ali N. , Holtfreter Birte , Friedrich Nele , Wallaschofski Henri , Nauck Matthias , Kocher Thomas
Published: December 2012

Aim. The aim was to compare the periodontal status of the acromegalic patients with healthy subjects from a large population-based cohort (Study of Health in Pomerania, SHIP). Materials and Methods. We studied 32 acromegalic patients (16 females) and 128 randomly selected SHIP subjects (controls) using a 1 : 4 matching. Serum IGF-I and IGFBP-3 levels were measured using the Immulite 2500 system. Periodontitis was assessed by clinical attachment loss (CAL), probing depth (PD), and number of missing teeth. Linear and logistic regression models were used to assess differences in periodontal variables between acromegalic patients and controls. Results. IGF-I levels were comparable in acromegalic patients and controls, whereas IGFBP-3 levels were significantly higher in acromegalic patients (). In multivariate modelling, both groups did not differ significantly with respect to mean CAL () and high tooth loss (). Mean PD was higher in acromegalic patients by trend ( (−0.00; 0.56)). Conclusion. In acromegalic patients, periodontal disease severity did not differ from their healthy SHIP controls.
Microdetermination of Methenamine in the Presence of Formaldehyde by Solid Phase Spectrophotometry
Authors: Taghdiri Mehdi , Yamini Yadollah , Moloudi Ali
Published: December 2012

A sensitive spectrophotometric method for the determination of methenamine has been developed without any separation steps. Bromocresol green is adsorbed on Sephadex LH-20 gel but the sorption decreases in the presence of methenamine due to ion-pair formation between bromocresol green and methenamine in solution. This attenuation was used to the microdetermination of methenamine by measurement of absorbance of the solid phase (Sephadex LH-20 gel) in a 1.0 mm cell at 625 nm. Methenamine could be determined in the concentration range of 0.42–1.68 μg mL−1 (10-mL Sample volume) with a relative standard deviation (RSD) of 0.03% (n=4). The detection limit obtained was 50 μg L−1 for 10 mL sample volume. The method was used for determination of methenamine in industrial wastewater and a satisfactory result was obtained.
Broken History and Crumbling Stones: The Romantic Conception of Architectural Preservation
Authors: Schönle Andreas
Published: December 2012

In this article Andreas Schönle explores the treatment of ruins in the Romantic period, in particular the propensity toward holistic reconstruction, rather than preservation of architectural heritage. He argues that the Romantic disregard of extant heritage harks back to the Sentimentalist infatuation with the fleetingness of life and dramatization of loss, that this melancholy feeling stoked a sense of national victimization, and that it legitimated an imaginary reinvention of the past and the constructedness of collective memory. The Church of the Tithe in Kiev serves as a case study illustrating that the Romantic commitment to totality has resulted in the significant destruction of architecture. Depictions of its ruins in travel accounts and in the writings of Vadim Passek and Andrei Murav'ev evidence a marked desire to exacerbate the sense of loss rather than to describe and valorize the remains. This disregard of heritage reprises the Sentimentalist infatuation with melancholy prominently deployed by Nikolai Karamzin. A comparison with Eugène Viollet-le-Duc in France and Augustus Pugin in England indicates that in Russia the invention of a national style of architecture required a much more radical imposition upon the historical landscape.
Maiakovskii and the Mobile Monument: Alternatives to Iconoclasm in Russian Culture
Authors: Rann James
Published: December 2012

This article examines Vladimir Maiakovskii's frequent references to statues and monuments in his poetry in relation to traditions of iconoclasm in Russian culture in order not only to shed light on the poet's attitude toward the role of the past in the creation of a new culture but also to investigate the way in which the destruction, relocation, and transformation of monuments, both in the urban landscape and in art, reflects political change in Russia. James Rann demonstrates that, while Maiakovskii often invoked a binary iconoclastic discourse in which creation necessitates destruction, his poetry also articulated a more nuanced vision of cultural change through the symbol of the moving monument: the statue is preserved but also transformed and liberated. Finally, an analysis of “Vo ves' golos” shows how Maiakovskii's myth of the statue helped him articulate his relationship to Soviet power and to his own poetic legacy.
Socialist Churches: Heritage Preservation and “Cultic Buildings” in Leningrad, 1924-1940
Authors: Kelly Catriona
Published: December 2012

The demolition of churches is a notorious episode in Soviet political history, normally discussed in the context of the history of church-state relations. Yet which prerevolutionary buildings were meant to fit into a “model socialist city” such as Leningrad and how this was to happen was also a planning issue. Soviet planners (unlike members of the militant atheist movement) drew a distinction between buildings and their (current or possible) functions. The monument protection agencies were often successful in arguing that buildings of “historic and artistic importance” should be preserved, even in the face of considerable pressure from other city departments (for example, the suggestion that Smol'nyi Cathedral be demolished for the bricks). However, they gave preference to churches that lacked an “odiously ecclesiastical appearance,” were ruthless about sacrificing churches that they deemed to be of secondary significance, and readily agreed to secular uses for “cultic buildings.” As Catriona Kelly shows in this article, most of the local intelligentsia considered these planning decisions to be appropriate; it was not until the postwar decades, and more particularly the Brezhnev era, that attitudes to “cultic buildings” began to change.
Prosperity without Security: The Precarity of Interpreters in Postsocialist, Postconflict Bosnia-Herzegovina
Authors: Baker Catherine
Published: December 2012

This article uses life history interview data collected during a project on languages and peace support operations in Bosnia-Herzegovina to consider, as an occupational group, people from former Yugoslavia who were employed as interpreters by foreign military forces. In exploring their opportunities for temporary prosperity and the sources of precarity that were associated with this distinctive form of work, Catherine Baker discusses the socioeconomic transformation of Bosnia-Herzegovina both in light of literature on postsocialist labor and in light of a global “development-security nexus” that may be observed during and after contemporary conflicts. Neither lens is sufficient for understanding the full extent of Bosnia-Herzegovina. Baker concludes by making the case for researchers of all postsocialist societies in central and eastern Europe, not just the societies that have direcdy experienced armed conflict, to take account of the global context of security, development, humanitarianism, and intervention.
Interactive Perception of Rigid and Non-Rigid Objects
Authors: Willimon Bryan , Birchfield Stan , Walker Ian
Published: December 2012

This paper explores the concept of interactive perception, in which sensing guides manipulation, in the context of extracting and classifying unknown objects within a cluttered environment. In the proposed approach, a pile of objects lies on a flat background, and the goal of the robot is to isolate, interact with, and classify each object so that its properties can be obtained. The algorithm considers each object to be classified using color, shape, and flexibility. The approach works with a variety of objects relevant to service robot applications, including both rigid objects such as bottles, cans, and pliers as well as non-rigid objects such as soft toy animals, socks, and shoes. Experiments on a number of different piles of objects demonstrate the ability of efficiently isolating and classifying each item through interaction.
Symmetrical Two-Dimensional PCA with Image Measures in Face Recognition
Authors: Meng Jicheng , Yang Yuming
Published: December 2012

In this paper, weextensively investigate symmetrical two-dimensional principal component analysis (S2DPCA) and introduce two image measures for S2DPCA-based face recognition, volume measure (VM) and subspace distance measure (SM). Although symmetrical featuresare an obviously but not absolutely facial characteristic, they have been successfully applied to PCA and 2DPCA. The paper gives detailed evidence that even and odd subspaces in S2DPCA are mutually orthogonal, and particularly that S2DPCA can be constructed using a quarter of the conventional S2DPCA even/odd covariance matrix. Based on these theories, we investigate the time and memory complexities of S2PDCA further, and find that S2DPCA can in fact be computed using a quarter of the time and memory compared to conventional S2DPCA. Finally, VM and SM are introduced to S2DPCA for final classification. Our experiments compare S2DPCA with 2DPCA on YALE, AR and FERET face databases, and the results indicate that S2DPCA+VM generally outperforms other algorithms.
Detection of Road Image Borders Based on Texture Classification
Authors: Graovac Stevica , Goma Ahmed
Published: December 2012

The concept of an algorithm developed for the segmentation of a road border from the content of an image produced by a forward looking TV camera mounted on a moving vehicle is presented in this paper. The extraction of a road boundary is an important step in the context of autonomous vehicle guidance, enabling further calculations of distance from the border, direction of a road, etc. The main idea behind this approach is that the texture of a road is different enough in comparison to the textures characterizing the surrounding environment, allowing the separation of the overall image into a few distinguishable regions. The segmentation algorithm combines the texture descriptors of a statistical nature and the ones based on a grey level co-occurrence matrix. The significance of this work is mainly in the practical verification of the proposed algorithm and in the testing of the real limits of its application.
Optimal Control Based on CACM-RL in a Two-Wheeled Inverted Pendulum
Authors: Gómez Mariano , Arribas Tomás , Sánchez Sebastián
Published: December 2012

This work aims to present a new optimal control scheme based on the CACM-RL technique applied tounstable systems such as a Two-Wheeled Inverted Pendulum (TWIP). The main challenge in this work is to verify and validate the good behaviour of CACM-RL in this kind of system. Learning while maintaining the equilibrium is a complex task. It is easy in stable platforms because the system never reaches an unstable state, but in unstable systems it is very difficult. The study also investigates implementing CACM-RL to coexist with a classic control solution. The results show that the proposed method works perfectly in unstable systems, providing better results than a PID controller.
Integrated Bi‐Layered Scaffold for Osteochondral Tissue Engineering
Authors: Galperin Anna , Floreani Rachael A. , Florczyk Stephen J. , Bryers James D. , Zhang Miqin , Ratner Buddy D.
Published: December 2012

Osteochondral tissue engineering poses the challenge of combining both cartilage and bone tissue engineering fundamentals. In this study, a sphere‐templating technique was applied to fabricate an integrated bi‐layered scaffold based on degradable poly(hydroxyethyl methacrylate) hydrogel. One layer of the integrated scaffold was designed with a single defined, monodispersed pore size of 38 μm and pore surfaces coated with hydroxyapatite particles to promote regrowth of subchondral bone while the second layer had 200 μm pores with surfaces decorated with hyaluronan for articular cartilage regeneration. Mechanical properties of the construct as well as cyto‐compatibility of the scaffold and its degradation products were elucidated. To examine the potential of the biphasic scaffold for regeneration of osteochondral tissue the designated cartilage and bone layers of the integrated bi‐layered scaffold were seeded with chondrocytes differentiated from human mesenchymal stem cells and primary human mesenchymal stem cells, respectively. Both types of cells were co‐cultured within the scaffold in standard medium without soluble growth/differentiation factors over four weeks. The ability of the integrated bi‐layered scaffold to support simultaneous matrix deposition and adequate cell growth of two distinct cell lineages in each layer during four weeks of co‐culture in vitro in the absence of soluble growth factors was demonstrated.
Factors Limiting Device Efficiency in Organic Photovoltaics
Authors: Janssen René A. J. , Nelson Jenny
Published: December 2012

The power conversion efficiency of the most efficient organic photovoltaic (OPV) cells has recently increased to over 10%. To enable further increases, the factors limiting the device efficiency in OPV must be identified. In this review, the operational mechanism of OPV cells is explained and the detailed balance limit to photovoltaic energy conversion, as developed by Shockley and Queisser, is outlined. The various approaches that have been developed to estimate the maximum practically achievable efficiency in OPV are then discussed, based on empirical knowledge of organic semiconductor materials. Subsequently, approaches made to adapt the detailed balance theory to incorporate some of the fundamentally different processes in organic solar cells that originate from using a combination of two complementary, donor and acceptor, organic semiconductors using thermodynamic and kinetic approaches are described. The more empirical formulations to the efficiency limits provide estimates of 10–12%, but the more fundamental descriptions suggest limits of 20–24% to be reachable in single junctions, similar to the highest efficiencies obtained for crystalline silicon p‐n junction solar cells. Closing this gap sets the stage for future materials research and development of OPV.
Efficiency of Nitrogen Desorption from LiX Zeolite by Rapid Oxygen Purge in a Pancake Adsorber
Authors: Chai Siew Wah , Kothare Mayuresh V. , Sircar Shivaji
Published: December 2012

Significance

A nonequilibrium, nonisothermal, nonisobaric model was used for numerical simulation of the efficiency of N2 desorption from a LiX zeolite column by rapid purge with O2 in a pancake adsorber. The key parameters included desorption time, adsorbent particle size, and the adsorber length to diameter ratio. The efficiency was found to be a complex function of these variables.
Initial thickness measurements and insights into crystal growth of methane hydrate film
Authors: Li Sheng‐Li , Sun Chang‐Yu , Liu Bei , Feng Xiu‐Jun , Li Feng‐Guang , Chen Li‐Tao , Chen Guang‐Jin
Published: December 2012

The initial thickness of methane hydrate film was directly measured by suspending a single methane bubble in water at 274.0, 276.0, and 278.0 K. The results show that the initial hydrate film thickness decreases from tens of micrometers to about 10 µm with the subcooling increased from 0.5 K to about 3 K. When subcooling is higher than 1.0 K, all initial film thickness data measured under different temperatures vary inversely with the subcooling. Notable three‐dimensional growths of hydrate crystals of different sizes and shapes at film front and emergence of new crystal were clearly observed at lower subcooling that resulting in the rougher surface of hydrate film and uncertainty of initial thickness measurement under lower subcooling. The hydrate film growth was dominated by film growth in thickness, not by lateral growth at low subcooling. The growth in thickness of hydrate shell covering one whole bubble surface was also investigated. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2145–2154, 2013
Neue Wege in der industriellen Chemieforschung im Spiegel derAngewandten Chemie
Authors: Kreimeyer Andreas
Published: December 2012

Mit der steigenden Komplexitätund der Vernetzung der Disziplinen hat sich das Bild der Chemiewissenschaften in den vergangenen Jahrzehnten gewandelt: Standen ursprünglich einzelne Moleküle im Mittelpunkt, geht es heute um „intelligente“ Chemie im Sinne ganzheitlicher Systeme. Wie Akademia und Industrie nachhaltige Antworten finden, hängt nicht zuletzt von der Qualität des wissenschaftlichen Dialogs ab, den dieAngewandte Chemieseit 125 Jahren dokumentiert und anstößt.
Ruthenium(II) complexes bearing pyridine‐based tridentate and bidentate ligands: catalytic activity for transfer hydrogenation of aryl ketones
Authors: Dayan Osman , Dayan Serkan , Kani İbrahim , Çetinkaya Bekir
Published: December 2012

Ru(II) complexes of the general formula [RuCl2(′′)(L)] (1: ′N = Nb, L = MeOH; 2: ′N = Nb, L = CH3CN; 3: ′N = Nd, L = CH3CN; 4: ′N = Np, L = CH3CN), [Ru(p‐cymene)(a–b)Cl]Cl (5a: N Na = 2,2′‐bipyridine; 5b: N Nb = 4,4′‐dimethyl–2,2′‐bipyridine), [Ru(′′)(a–b)Cl]Cl (6a: ′N = Nb, a = 2,2′‐bipyridine; 6b: ′N = Nb, b = 4,4′‐dimethyl‐2,2′‐bipyridine; 7a: ′N = Nd, a = 2,2′‐bipyridine; 7b: ′N = Nd, b = 4,4′‐dimethyl‐2,2′‐bipyridine; 8a: ′N = Np, a = 2,2′‐bipyridine; 8b: ′N = Np, b = 4,4′‐dimethyl‐2,2′‐bipyridine) and [Ru(′′)(a)Cl]BF4 (9a: ′N = Nb; a = 2,2′‐bipyridine) were synthesized from the corresponding [RuCl2(p‐cymene)]2 dimer, ′′ and a–b ligands. The compounds were characterized by elemental analysis, IR and NMR. Complex 9a was studied by X‐ray diffraction, confirming its cationic‐mononuclear [RuCl(bb)(a)]+ nature. The synthesized Ru(II) complexes (1–8) were employed as catalysts for the transfer hydrogenation of ketones to secondary alcohols in the presence of KOH using 2‐propanol as a hydrogen source at 82°C. The rates of the transfer hydrogenation reactions strongly depended on the type of and ancillary ligands. Copyright © 2012 John Wiley & Sons, Ltd.
Integrating pelagic and coastal MPAs into large‐scale ecosystem‐wide management
Authors: Guidetti P. , Notarbartolo‐Di‐Sciara G. , Agardy T.
Published: December 2012

Marine Protected Areas (MPAs) have gained increasing popularity worldwide as tools for biodiversity conservation and management of human uses. This rise in popularity has been accompanied by an increasing body of scientific papers and books on MPA design and management, the vast majority of which are almost completely focused on coastal or insular MPAs.

A small number of MPAs have also been established in the pelagic domain, however, these pelagic sites have been considered in isolation from coastal/insular MPAs, even when the sites are adjacent or nearby. Pelagic and coastal ecosystems are not at all isolated from each other, but interconnected both physically via the flow of water, and biologically, via the movement of organisms.

In order to maximize the effectiveness of MPAs, it is suggested that spatial management planning encompass large areas that span both coastal and pelagic domains. This requires integrated, large‐scale spatial management, which may extend across borders and thus require international cooperation.

Copyright © 2012 John Wiley & Sons, Ltd.