bluuebunny/crossref_metadata_2025 huggingface dataset:
Co-intercalation in PP Clay Nanocomposites: Effect of Short Chain Additives on Rheological Properties
Authors: Haworth B. , Ratnayake U. N.
Published: March 2011

Layered structures in inorganic minerals are not easily intercalated when combined with conventional non-polar polymers such as polypropylene (PP). A new co-intercalation method is reported whereby the combined influence of low molecular weight polar additives and polyolefin-based compatibilizers on PP-clay nanocomposites (PPCN) has been investigated. Our research has shown that the interlayer spacing of montmorillonite clay increases dramatically, and increased particle dispersion is achieved, when short chain, organic additives (typically amide-type, AM) are included. In this work, the migration of these additives into the clay galleries has been confirmed by surface energy data (from contact angle experiments) and by various capillary flow measurement techniques. Shear flow data have been used to interpret the mechanism of intercalation, following compound preparation using melt-state mixing processes. At relatively low concentrations, the erucamide molecules assist the intercalation process in nanocomposites; however if an excess of AM is apparent within the bulk polymer melt, unusual flow behavior is observed which can be attributed to wall slip. Modified melt elasticity is also obtained with the PPCN's leading to reduced die swell characteristics in extrusion processes. Significant differences in melt flow behavior can therefore be attributed to the presence of AM; a mechanism for co-intercalation has been proposed in terms of hydrogen bonding between the additives and the silicate layers.
Good Sense, Art, and Morality in Hume's ‘Of the Standard of Taste’
Authors: Winegar Reed
Published: March 2011

In his essay ‘Of the Standard of Taste,’ Hume argues that artworks with morally flawed outlooks (including Homer's poems) are, to some extent, aesthetically flawed. While Hume's remarks regarding the relationship between art and morality have influenced contemporary aestheticians, Hume's own position has struck many people as incoherent. For Hume appears to entangle himself in two separate contradictions. First, Hume seems to claim both that true judges should not enter into vicious sentiments and that true judges should adopt the standpoint of an artwork's intended audience. But The Iliad, say, was obviously intended for an audience that shared Homer's flawed moral outlook. Second, Hume appears to claim that our moral sentiments are both highly resistant to change and extremely fragile. This essay defends Hume against these two objections by drawing increased attention to the role that Hume's aesthetics assigns to the faculty of good sense or sound reason.
Adam Smith's ‘Sympathetic Imagination’ and the Aesthetic Appreciation of Environment
Authors: Brady Emily
Published: March 2011

This paper explores the significance of Adam Smith's ideas for defending non-cognitivist theories of aesthetic appreciation of nature. Objections to non-cognitivism argue that the exercise of emotion and imagination in aesthetic judgement potentially sentimentalizes and trivializes nature. I argue that although directed at moral judgement, Smith's views also find a place in addressing this problem. First, sympathetic imagination may afford a deeper and more sensitive type of aesthetic engagement. Second, in taking up the position of the impartial spectator, aesthetic judgements may originate in a type of self-regulated response where we stand outside ourselves to check those overly humanizing tendencies which might lead to a failure in appreciating nature as nature.
Remarks on the Varieties of Prejudice in Hume's Essay on Taste
Authors: Kivy Peter
Published: March 2011

The last of Hume's five requirements of the ‘true judge in the finer arts’, is that he be ‘cleared of all prejudice…'. I argue here that, lurking in this innocuous-sounding requirement of the true judge, is a complexity that reveals a significant tension in Hume's argument. It is that tension that I want briefly to explore.
Ideal Presence: How Kames Solved the Problem of Fiction and Emotion
Authors: Dadlez Eva
Published: March 2011

The problem of fiction and emotion is the problem of how we can be moved by the contemplation of fictional events and the plight of fictional characters when we know that the former have not occurred and the latter do not exist. I will give a general sketch of the philosophical treatment of the issue in the present day, and then turn to the eighteenth century for a solution as effective as the best that are presently on offer. The solution is to be found in the account of ideal presence given by Henry Home, Lord Kames.
An Evolutionary Explanation for the Perturbation of the Dynamics of Metastatic Tumors Induced by Surgery and Acute Inflammation
Authors: Carmona Bayonas Alberto
Published: March 2011

Surgery has contributed to unveil a tumor behavior that is difficult to reconcile with the models of tumorigenesis based on gradualism. The postsurgical patterns of progression include unexpected features such as distant interactions and variable rhythms. The underlying evidence can be summarized as follows: (1) the resection of the primary tumor is able to accelerate the evolution of micrometastasis in early stages, and (2) the outcome is transiently opposed in advanced tumors. The objective of this paper is to give some insight into tumorigenesis and surgery-related effects, by applying the concepts of the evolutionary theory in those tumor behaviors that gompertzian and tissular-centered models are unable to explain. According to this view, tumors are the consequence of natural selection operating at the somatic level, which is the basic mechanism of tumorigenesis, notwithstanding the complementary role of the intrinsic constrictions of complex networks. A tumor is a complicated phenomenon that entails growth, evolution and development simultaneously. So, an evo-devo perspective can explain how and why tumor subclones are able to translate competition from a metabolic level into neoangiogenesis and the immune response. The paper proposes that distant interactions are an extension of the ecological events at the local level. This notion explains the evolutionary basis for tumor dormancy, and warns against the teleological view of tumorigenesis as a process directed towards the maximization of a concrete trait such as aggressiveness.
REDD+, RFM, Development, and Carbon Markets
Authors: Louman Bastiaan , Cifuentes Miguel , Chacón Mario
Published: March 2011

Combining responsible forest management (RFM) experiences with literature reviews and stakeholder discussions allows an assessment of the potential role of RFM in reduced emissions from deforestation and forest degradation and conservation, sustainable forest management and enhancement of carbon stocks (REDD+). RFM contributes to greater carbon storage and biodiversity in forest biomass in comparison to conventional logging and deforestation. Using an adjusted von Thünen model to explain land user behavior in relation to different variables, considering a general forest transition curve and looking at a potential relation between governance and deforestation rates, the authors conclude that reduction of deforestation and forest degradation can only be achieved by a combined approach of increasing forest rent relative to other land uses and reducing transaction costs for forest management and conservation. More than providing an additional income for a privileged few, REDD+ will need to address the barriers that have been identified in RFM over the past 30 years of investment in forest management and conservation. Most of these are of an institutional nature, but also culture and social organization as well as locally specific development trends play a significant role in increasing the potential for application of RFM and REDD+.
Antinociceptive and Anti-Inflammatory Activity from Algae of the Genus Caulerpa
Authors: Brito da Matta Carolina Babosa , De Souza Éverton Tenório , De Queiroz Aline Cavalcanti , De Lira Daysianne Pereira , De Araújo Morgana Vital , Cavalcante-Silva Luiz Henrique Agra , De Miranda George Emmanuel C. , De Araújo-Júnior João Xavier , Barbosa-Filho José Maria , De Oliveira Santos Bárbara Viviana , Alexandre-Moreira Magna Suzana
Published: March 2011

Marine natural products have been the focus of discovery for new products of chemical and pharmacological interest. The aim of this study was to evaluate the antinociceptive activity of the methanolic (ME), acetate (AE), hexanic (HE) and chloroform (CE) extracts obtained from Caulerpa mexicana, and ME, CE and HE obtained from Caulerpa sertularioides. These marine algae are found all over the world, mainly in tropical regions. Models such as the writhing test, the hot plate test and formalin-induced nociception test were used to evaluate antinociceptive activity in laboratory mice. In the writhing test, all the extracts were administered orally at a concentration of 100 mg/kg, and induced high peripheral antinociceptive activity, with a reduction in the nociception induced by acetic acid above 65%. In the hot plate test, treatment with extracts from C. sertularioides (100 mg/kg, p.o.) did not significantly increase the latency of response, although the ME, AE and HE from C. mexicana showed activity in this model. This result suggests that these extracts exhibit antinociceptive activity. In the formalin test, it was observed that ME, AE and HE obtained from C. mexicana reduced the effects of formalin in both phases. On the other hand only CE from C. sertularioides induced significant inhibition of the nociceptive response in the first phase. To better assess the potential anti-inflammatory activity of the extracts, the carrageenan-induced peritonitis test was used to test Caulerpa spp. extracts on cell migration into the peritoneal cavity. In this assay, all extracts evaluated were able to significantly inhibit leukocyte migration into the peritoneal cavity in comparison with carrageenan. These data demonstrate that extracts from Caulerpa species elicit pronounced antinociceptive and anti-inflamatory activity against several nociception models. However, pharmacological and chemical studies are continuing in order to characterize the mechanism(s) responsible for the antinociceptive action and also to identify the active principles present in the Caulerpa species.
From Symmetric Glycerol Derivatives to Dissymmetric Chlorohydrins
Authors: Solarte Carmen , Escribà Marc , Eras Jordi , Villorbina Gemma , Canela Ramon , Balcells Mercè
Published: March 2011

The anticipated worldwide increase in biodiesel production will result in an accumulation of glycerol for which there are insufficient conventional uses. The surplus of this by-product has increased rapidly during the last decade, prompting a search for new glycerol applications. We describe here the synthesis of dissymmetric chlorohydrin esters from symmetric 1,3-dichloro-2-propyl esters obtained from glycerol. We studied the influence of two solvents: 1,4-dioxane and 1-butanol and two bases: sodium carbonate and 1-butylimidazole, on the synthesis of dissymmetric chlorohydrin esters. In addition, we studied the influence of other bases (potassium and lithium carbonates) in the reaction using 1,4-dioxane as the solvent. The highest yield was obtained using 1,4-dioxane and sodium carbonate.
Sub-Micron Particle Based Structures as Reconfigurable Photonic Devices Controllable by External Photonic and Magnetic Fields
Authors: Shahmoon Asaf , Meiri Amihai , Zalevsky Zeev
Published: March 2011

In this paper we present the configurations of two nanometer scale structures—one of them optically controllable and the second one magnetically controllable. The first involves an array of nanoparticles that are made up of two layers (i.e., Au on top of a Si layer). The device may exhibits a wide range of plasmonic resonance according to external photonic radiation. The second type of device involves the usage of sub micron superparamagnetic particles located on a suitable structuring grid, that according to the angle of the external magnetic field allows control of the length of the structuring grid and therefore control the diffraction order of each wavelength.
A Virtual Sensor for Online Fault Detection of Multitooth-Tools
Authors: Bustillo Andres , Correa Maritza , Reñones Anibal
Published: March 2011

The installation of suitable sensors close to the tool tip on milling centres is not possible in industrial environments. It is therefore necessary to design virtual sensors for these machines to perform online fault detection in many industrial tasks. This paper presents a virtual sensor for online fault detection of multitooth tools based on a Bayesian classifier. The device that performs this task applies mathematical models that function in conjunction with physical sensors. Only two experimental variables are collected from the milling centre that performs the machining operations: the electrical power consumption of the feed drive and the time required for machining each workpiece. The task of achieving reliable signals from a milling process is especially complex when multitooth tools are used, because each kind of cutting insert in the milling centre only works on each workpiece during a certain time window. Great effort has gone into designing a robust virtual sensor that can avoid re-calibration due to, e.g., maintenance operations. The virtual sensor developed as a result of this research is successfully validated under real conditions on a milling centre used for the mass production of automobile engine crankshafts. Recognition accuracy, calculated with a k-fold cross validation, had on average 0.957 of true positives and 0.986 of true negatives. Moreover, measured accuracy was 98%, which suggests that the virtual sensor correctly identifies new cases.
Systematic Prioritization of the STARE-HI Reporting Items
Authors: Talmon J. , Ammenwerth E. , Brender J. , Rigby M. , Nykanen P. , de Keizer N. F.
Published: March 2011

Background: We previously devised and published a guideline for reporting health informatics evaluation studies named STARE-HI, which is formally endorsed by IMIA and EFMI.

Objective: To develop a prioritization framework of ranked reporting items to assist authors when reporting health informatics evaluation studies in space restricted conference papers and to apply this prioritization framework to measure the quality of recent health informatics conference papers on evaluation studies.

Method: We deconstructed the STARE-HI guideline to identify reporting items. We invited a total of 111 authors of health informatics evaluation studies, reviewers and editors of health Informatics conference proceedings to score those reporting items on a scale ranging from “0 – not necessary in a conference paper” through to “10 – essential in a conference paper” by a web-based survey. From the responses we derived a mean priority score. All evaluation papers published in proceedings of MIE2006, Medinfo2007, MIE2008 and AMIA2008 were rated on these items by two reviewers. From these ratings a priority adjusted completeness score was computed for each paper.

Results: We identified 104 reporting items from the STARE-HI guideline. The response rate for the survey was 59% (66 out of 111). The most important reporting items (mean score ≥ 9) were “Interpret the data and give an answer to the study question – (in Discussion)”, “Whether it is a laboratory, simulation or field study – (in Methods-study design)” and “Description of the outcome measure/evaluation criteria – (in Methods-study design)”. Per reporting area the statistically more significant important reporting items were distinguished from less important ones. Four reporting items had a mean score ≤ 6. The mean priority adjusted completeness of evaluation papers of recent health informatics conferences was 48% (range 14 –78%).

Conclusion: We produced a ranked list of reporting items from STARE-HI according to their prioritized relevance for inclusion in space-limited conference papers. The priority adjusted completeness scores demonstrated room for improvement for the analyzed conference papers. We believe that this prioritization framework is an aid to improving the quality and utility of conference papers on health informatics evaluation studies.
A review of extra-articular prosthetic stabilization of the cranial cruciate ligament-deficient stifle
Authors: Tonks C. A. , Lewis D. D. , Pozzi A.
Published: March 2011

Extra-articular prosthetic stabilization techniques have been used as a method of stabilization of the cranial cruciate ligament (CrCL)-deficient stifle for decades. During extra-articular prosthetic stabilization, the prosthesis is anchored to the femur and tibia, and tensioned in the attempt to resolve femorotibial instability. The position of the anchor points of the prosthesis is crucial for restoring a normal range of joint motion and mitigating alterations in prosthesis tension during motion. Recently developed techniques offer several innovations with potential advantages such as bone-to-bone fixation, prosthetic materials with better mechanical properties, and improved isometry of the anchor points. Whether these innovations provide clinically superior results to the traditional techniques such as lateral circumfabellar-tibial suture techniques has yet to be determined.
Treatment of fractures of the distal radius and ulna in toy breed dogs with circular external skeletal fixation: a retrospective study
Authors: Cappellari F. , Peirone B. , Ferretti A. , Piras L.
Published: March 2011

Objective: To evaluate the effectiveness of circular external skeletal fixation (CESF) in treating fractures of the distal radius and ulna in toy breed dogs, and to document the type and frequency of complications associated with this technique.

Methods: The medical records of small breed dogs with fractures of the distal radius and ulna admitted to the University of Turin and to the Clinica Ferretti between 2002 and 2009 were retrospectively reviewed. The criteria for inclusion of cases in the study were: body weight of 5 kg or less, transverse or short oblique fracture of the distal third of the radius and ulna, no previous repair attempts, and treatment with CESF as the sole method of fixation.

Results: Twenty fractures in 16 dogs satisfied the criteria for inclusion into this study. No signs of infection or failure of fixation were detected in any case. Mean frontal plane alignment was 4.7° ± 2.7° and mean sagittal plane alignment was 12.7° ± 7.2°. Postoperative complications occurred in one patient. All fractures achieved union. Mean time until radiographic evidence of a bridging callus and subsequent implant removal was 71 days (range: 30–120).

Conclusions: The results of this study support the use of CESF for treatment of fractures of the distal radius and ulna in toy breed dogs as an alternative to other methods of fracture fixation. However, this technique requires a series of follow-up examinations to evaluate the stability of the apparatus, the soundness of the wires and to determine the appropriate time for implant removal.
Nevirapine versus Atazanavir/Ritonavir, Each Combined with Tenofovir Disoproxil Fumarate/Emtricitabine, in Antiretroviral-Naive HIV-1 Patients: The Arten Trial
Authors:   ARTEN investigators, Soriano Vicente , Arastéh Keikawus , Migrone Horacio , Lutz Thomas , Opravil Milos , Andrade-Villanueva Jaime , Antunes Francisco , Perri Giovanni Di , Podzamczer Daniel , Taylor Steve , Domingo Pere , Gellermann Holger , de Rossi Lothar
Published: March 2011

Background

Selection of first-line antiretroviral therapy requires consideration of efficacy as well as effects on lipids given the increased concern about cardiovascular risk in HIV-1 patients.

Methods

ARTEN is a randomized, open-label, non-inferiority trial that compares nevirapine (NVP) 200 mg twice daily or 400 mg once daily to atazanavir/ritonavir (ATZ/r) 300 mg/100 mg once daily, each combined with fixed-dose tenofovir disoproxil fumarate (TDF) 300 mg/ emtricitabine (FTC) 200 mg once daily, in antiretroviral-naive HIV-1 patients with CD4+ T-cell counts <400 (men) and <250 cells/mm3 (women). The primary end point was plasma HIV RNA<50 copies/ml at two consecutive visits prior to week 48.

Results

A total of 569 patients were randomized and treated. Overall, 66.8% of NVP and 65.3% of ATZ/r patients achieved the primary end point (difference 1.9%, 95% CI -5.9–9.8%). Similar rates of serious adverse events were observed (9.6% on NVP versus 8.8% on ATZ/r), although discontinuations due to adverse events were more frequent with NVP than ATZ/r (13.6% versus 3.6%, respectively). None of the 28 patients virologically failing ATZ/r selected resistance mutations, while they were selected in 29/44 patients virologically failing NVP. NVP induced a significantly greater increase in high-density lipoprotein cholesterol (HDL-c) and apolipoprotein A1 from baseline than ATZ/r, whereas triglycerides increased significantly more with ATZ/r than NVP. Mean change from baseline in TC:HDL-c ratio was -0.24 for NVP and 0.13 for ATZ/r ( P=0.0001).

Conclusions

NVP demonstrated at week 48 non-inferior antiviral efficacy compared with ATZ/r when given along with TDF/FTC, despite more drug-related discontinuations with NVP than ATZ/r. NVP was associated with a lower atherogenic lipid profile than ATZ/r although resistance mutations were more frequently selected with NVP than ATZ/r.
L'agressivité motrice en questions au sein du football
Authors: Hebert Thibaut , Dugas Éric
Published: March 2011

Résumé L’objectif de cette recherche est d’étudier les connotations associées à l’agressivité motrice en football. À l’aide du questionnement direct (enquête d’opinion et la méthode de la comparaison par paires) et du questionnement indirect (différenciateur sémantique), l’enquête interroge différents groupes de sujets ( n = 250 ) – des enseignants d’éducation physique et sportive (EPS), des footballeurs et des non pratiquants – sur leur perception de l’agressivité dans le football et ce, dans deux institutions distinctes, le club et l’EPS. Les résultats révèlent globalement que l’agressivité n’est pas obligatoirement perçue comme une transgression des règles mais peut faire partie du jeu. Pour autant, les non pratiquants semblent plus réticents à ce type d’agressivité. Par ailleurs, les enseignants d’EPS, assez neutres sur les connotations liées au football, se distinguent significativement des autres sous-populations : ils évoquent les injures envers les arbitres comme acte le plus agressif ; en EPS, ils ne placent pas la victoire comment objectif principal, alors que la logique interne du football est un duel d’équipes pour obtenir le gain du match. Autrement dit, être « agressif » pour gagner. De fait, ces résultats interrogent, notamment, quant à l’approche de ce sport en milieu scolaire.
Cohérence et diversité de la science du sport en Allemagne
Authors: Kurz Dietrich
Published: March 2011

Résumé Le texte présenté ici a été réalisé lors d’une conférence concernant le trentième anniversaire de la création des sciences du sport en Allemagne. Il discute la question de la cohérence des sciences du sport, ainsi que celle de leur diversité à partir notamment des discours mis en œuvre lors des différents congrès de l’association allemande des sciences du sport. Il montre que si, dès l’origine, un fantasme d’unité anime la science du sport (à l’instar de son nom) la réalité des recherches est tout autre et la diversité est notamment liée à l’utilité sociale et aux formations. Cependant la science du sport semble avoir atteint ses limites en tant que territoire et sa non-définition réelle en tant qu’objet théorique peut lui poser de réels problèmes au moment d’un resserrement des critères universitaires allemands. Un moment fondée sur le rêve d’un « sport meilleur », puis de la fondation d’une formation professionnelle d’enseignant, elle demeure aujourd’hui éclatée en divers objets.
Universal Series on a Riemann Surface
Authors: Clouâtre Raphäel
Published: March 2011

Every holomorphic function on a compact subset of a Riemann surface can be uniformly approximated by partial sums of a given series of functions. Those functions behave locally like the classical fundamental solutions of the Cauchy–Riemann operator in the plane.
Giant Insulinoma in Uncinate Region Treated by Enucleation
Authors: Matkari SP , Bhingare PD , Jahagirdar DP , Chirmade RA
Published: March 2011

A 32-year-old male patient, a known case of chronic myeloid leukemia (CML) with 11 × 9 cm GIANT functioning insulinoma in the uncinate region of pancreas, with no local invasion or metastatic disease, is presented. In view of CML, enucleation of the tumor done. Histopathology was s/o ‘insulinoma of uncertain biological behavior’. Postoperatively, the patient was followed up for one year and found normal.
Severe Hypercalcemia due to Primary Hyperparathyroidism with MEN 2A
Authors: Thompson Geoffrey B , Dy Benzon M , Vazquez Bianca , Tebben Peter J , Kumar Seema
Published: March 2011

Introduction

Severe hypercalcemia due to primary hyperparathyroidism (PHPT) is rare in the setting of MEN 2A.

Materials and methods

Two patients with MEN 2A and severe hypercalcemia were identified recently. Their clinical presentation, evaluation, surgical management and outcomes are reviewed.

Results

Two patients with MEN 2A were identified with severe hypercalcemia secondary to a parathyroid adenoma. Calcium levels were elevated to 12.7 mg/dL and 15.1 mg/dL, respectively (normal range = 8.9-10.1 mg/dL). In each case, a single parathyroid adenoma was identified and surgically excised with normalization of parathyroid and calcium levels postoperatively. Clinical manifestations at the time of diagnosis included constipation, polyuria, hypercalciuria, and decreased bone mineral density.

Conclusion

Severe elevation of serum calcium is a rare presentation of PHPT in MEN2A. The differential diagnosis should include parathyroid adenoma, hyperplasia and parathyroid carcinoma. Early surgical management is essential in the treatment of hyperparathyroidism with severe hypercalcemia to prevent further complications.
Pheochromocytoma is an Eventful Tumor: A Case Description
Authors: PRK Bhargav , V Amar
Published: March 2011

Pheochromocytoma is a tumor arising from adrenal medulla in > 90% of cases. It is a great mimic, featuring in differential diagnosis of disorders of multiple organ systems. Here we present a prototypical case of right adrenal pheochromocytoma, highlighting this unique feature of the tumor. It presented with repeated hypertensive crises with predominant involvement of one major organ system in each episode. All of them were reversible with timely intervention and successful removal of the tumor, highlighting the functional basis rather than organic pathology.
Thyroid Hemiagenesis and Papillary Carcinoma: A Rare Association
Authors: P Tammaro , M Nunziante , M Del Prete , L Asciore , F Nappi , Lupoli Ge , Gi Lupoli , A Porcelli , Marzano LA
Published: March 2011

Hemiagenesis is the least frequent thyroid congenital anomaly. We report the case of a primary hypothyroidism due to thyroid hemiagenesis in a patient for whom, later on, a papillary carcinoma of the contralateral lobe was diagnosed. A child with known left lobe thyroid agenesis was found to have a 12 mm nodule in the right thyroid lobe during routine follow-up. Needle biopsy demonstrated the nodule to represent a papillary thyroid cancer and total thyroidectomy and lymphadenectomy of the central compartment was undertaken. Such event represents an extremely rare occurrence since there are only five other reports in literature that deal with a papillary carcinoma in a patient with thyroid hemiagenesis.
Impact of the East Asian summer monsoon on long-term variations in the acidity of summer precipitation in Central China
Authors: Ge B. Z. , Wang Z. F. , Xu X. B. , Tang J. , He Y. J. , Uno I. , Ohara T.
Published: March 2011

Abstract. The acidity of precipitation has been observed at stations of the Acid Rain Monitoring Network run by the China Meteorological Administration (CMA-ARMN) since 1992. Previous studies have shown that different long-term trends exist in different regions but detailed analysis of the causes of these is lacking. In this paper, we analyze summertime precipitation acidity data from the CMA-ARMN during 1992–2006 using EOFs and show that the summertime pH in China had different trends before and after 2000. The most significant decrease of pH is found in Central China. To investigate the causes of this decrease of pH in summer, we explore the relationship between changes in the pH value, the East Asian summer monsoon index, rainfall data, and pollutants emissions. We find that the East Asian summer monsoon can significantly affect the acidity of summer precipitation in Central China. In strong monsoon years, the pH in Central China is about 0.33 lower than that in weak monsoon years. Chemical transport model simulations using fixed emissions indicate that about 65% of the pH value difference (i.e., 0.22) is related to the summer monsoon, and constitutes 18–36% of the observed pH change (0.6∼1.2) in Central China during 1992–2006. Further studies reveal a relationship between the pH in Central China and the rainfall in the middle and lower reaches of the Yangtze River (MLYR), which can explain about 24% of the variance of pH in Central China. Simulations using an annually varying emission inventory show that at least 60% of the variation in precipitation acidity in Central China can be attributed to changes in pollutant emissions. Therefore, the increase in emissions of acidic species is the most important cause for the observed decrease of pH in Central China, and changes in meteorological factors, such as rainfall and other parameters related to the East Asian summer monsoon, play a less important but still significant role.
Technical Note: Estimating fusion properties for polyacids
Authors: Compernolle S. , Ceulemans K. , Müller J.-F.
Published: March 2011

Abstract. Organic aerosol (OA) components are generally assumed to be liquid-like. Hence, to describe the partitioning of these components, the liquid vapor pressure of these components is desired. Polyacids and functionalized polyacids can be a significant part of OA. But often, measurements are available only for solid state vapor pressure, which can differ by orders of magnitude from their liquid counterparts. To convert such a sublimation pressure to a subcooled liquid vapor pressure, fusion properties (two out of these three quantities: fusion enthalpy, fusion entropy, fusion temperature) are required. Unfortunately, experimental knowledge of fusion properties is sometimes missing in part or totally, hence an estimation method is required. Several fusion data estimation methods are tested here against experimental data of polyacids. Next, we develop a simple estimation method, specifically for this kind of compounds, reducing significantly the estimation error.
Source identification and airborne chemical characterisation of aerosol pollution from long-range transport over Greenland during POLARCAT summer campaign 2008
Authors: Schmale J. , Schneider J. , Ancellet G. , Quennehen B. , Stohl A. , Sodemann H. , Burkhart J. , Hamburger T. , Arnold S. R. , Schwarzenboeck A. , Borrmann S. , Law K. S.
Published: March 2011

Abstract. We deployed an aerosol mass spectrometer during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) summer campaign in Greenland in June/July 2008 on the research aircraft ATR-42. Online size resolved chemical composition data of submicron aerosol were collected up to 7.6 km altitude in the region 60 to 71° N and 40 to 60° W. Biomass burning (BB) and fossil fuel combustion (FF) plumes originating from North America, Asia, Siberia and Europe were sampled. Transport pathways of detected plumes included advection below 700 hPa, air mass uplifting in warm conveyor belts, and high altitude transport in the upper troposphere. By means of the Lagrangian particle dispersion model FLEXPART, trace gas analysis of O3 and CO, particle size distributions and aerosol chemical composition 48 pollution events were identified and classified into five chemically distinct categories. Aerosol from North American BB consisted of 22% particulate sulphate, while with increasing anthropogenic and Asian influence aerosol was composed of up to 37% sulphate category mean value. Overall, it was found that the organic matter fraction was larger (85%) in pollution plumes than for background conditions (71%). Despite different source regions and emission types the particle oxygen to carbon ratio of all plume classes was around 1 indicating low-volatile highly oxygenated aerosol. Also the volume size distributions were rather similar for all sampled plume categories. This can be explained by the relatively long transport times of roughly one week from North America and two weeks from Asia/Siberia. The derived aerosol lifetime for North American emissions was about 9 ± 2 days.
Mass and chemical composition of size-segregated aerosols (PM1, PM2.5, PM10) over Athens, Greece: local versus regional sources
Authors: Theodosi C. , Grivas G. , Zarmpas P. , Chaloulakou A. , Mihalopoulos N.
Published: March 2011

Abstract. To identify the relative contribution of local versus regional sources of particulate matter (PM) in the Greater Athens Area (GAA), simultaneous mass and chemical composition measurements of size segregated particulate matter (PM: PM1, PM2.5 and PM10) were carried out from September 2005 to August 2006 at three locations: one urban (Goudi, Central Athens) and one suburban (Lykovrissi, Athens) in GAA and the third in a regional background site (Finokalia, Crete). The two stations in GAA exceeded the EU-legislated PM10 limit values, both in terms of annual average (59.0 and 53.6 μg m−3 for Lykovrissi and Goudi, respectively) and of 24-h value, while the concentration levels at the remote site of Finokalia indicated an elevated background. High levels of PM2.5 and PM1 were also found at all locations (23.5 and 18.6 for Lykovrissi, while 29.4 and 20.2 μg m−3 for Goudi, respectively). Significant correlations were observed between same PM fractions at both GAA sites indicating important spatial homogeneity within GAA. During the warm season, the PM1 ratio between the GAA and the background site ranged from 1.1 to 1.3. On the other hand this ratio was significantly higher (1.6–1.7) during the cold season highlighting the role of long-range transport and local sources during the warm and cold seasons respectively. Similar seasonal and geographical patterns were observed for nss-SO42−, a secondary compound characteristic of regional sources, confirming the above hypothesis. Regarding the coarse fraction no such seasonal trend was observed for both GAA sites with their ratio (GAA site/Finokalia) being higher than 2 indicating significant contribution from local sources such as road dust and/or constructions as confirmed by Ca2+ measurements. Chemical speciation data showed that on a yearly basis, ionic and crustal mass represent up to 78% of the gravimetrically determined mass for PM10 samples in GAA. The unidentified mass might be attributed to organic carbon (OC) and elemental carbon (EC), in agreement with the results reported by earlier studies in central Athens. The contribution of local sources at both GAA sites was also estimated by considering mass and chemical composition measurements at Finokalia as representative of the regional background. Carbonaceous material, Particulate Organic Matter (POM) and EC, seemed to be the main contributor of the local PM mass within GAA (up to 62% in PM1). Dust from local sources (mainly resuspension) contributed also significantly to the local PM10 mass (up to 33%).
Characterization of aerosol photooxidation flow reactors: heterogeneous oxidation, secondary organic aerosol formation and cloud condensation nuclei activity measurements
Authors: Lambe A. T. , Ahern A. T. , Williams L. R. , Slowik J. G. , Wong J. P. S. , Abbatt J. P. D. , Brune W. H. , Ng N. L. , Wright J. P. , Croasdale D. R. , Worsnop D. R. , Davidovits P. , Onasch T. B.
Published: March 2011

Abstract. Motivated by the need to develop instrumental techniques for characterizing organic aerosol aging, we report on the performance of the Toronto Photo-Oxidation Tube (TPOT) and Potential Aerosol Mass (PAM) flow tube reactors under a variety of experimental conditions. The PAM system was designed with lower surface-area-to-volume (SA/V) ratio to minimize wall effects; the TPOT reactor was designed to study heterogeneous aerosol chemistry where wall loss can be independently measured. The following studies were performed: (1) transmission efficiency measurements for CO2, SO2, and bis(2-ethylhexyl) sebacate (BES) particles, (2) H2SO4 yield measurements from the oxidation of SO2, (3) residence time distribution (RTD) measurements for CO2, SO2, and BES particles, (4) aerosol mass spectra, O/C and H/C ratios, and cloud condensation nuclei (CCN) activity measurements of BES particles exposed to OH radicals, and (5) aerosol mass spectra, O/C and H/C ratios, CCN activity, and yield measurements of secondary organic aerosol (SOA) generated from gas-phase OH oxidation of m-xylene and α-pinene. OH exposures ranged from (2.0 ± 1.0) × 1010 to (1.8 ± 0.3) × 1012 molec cm−3 s. Where applicable, data from the flow tube reactors are compared with published results from the Caltech smog chamber. The TPOT yielded narrower RTDs. However, its transmission efficiency for SO2 was lower than that for the PAM. Transmission efficiency for BES and H2SO4 particles was size-dependent and was similar for the two flow tube designs. Oxidized BES particles had similar O/C and H/C ratios and CCN activity at OH exposures greater than 1011 molec cm−3 s, but different CCN activity at lower OH exposures. The O/C ratio, H/C ratio, and yield of m-xylene and α-pinene SOA was strongly affected by reactor design and operating conditions, with wall interactions seemingly having the strongest influence on SOA yield. At comparable OH exposures, flow tube SOA was more oxidized than smog chamber SOA, possibly because of faster gas-phase oxidation relative to particle nucleation. SOA yields were lower in the TPOT than in the PAM, but CCN activity of flow-tube-generated SOA particles was similar. For comparable OH exposures, α-pinene SOA yields were similar in the PAM and Caltech chambers, but m-xylene SOA yields were much lower in the PAM compared to the Caltech chamber.
Diel variations in the carbon isotope composition of respired CO2 and associated carbon sources: a review of dynamics and mechanisms
Authors: Werner C. , Gessler A.
Published: March 2011

Abstract. Recent advances have improved our methodological approaches and theoretical understanding of post-photosynthetic carbon isotope fractionation. Nevertheless we still lack a clear picture of the origin of short-term variability in δ13C of respired CO2 (δ13Cres) and organic carbon fractions on a diel basis. However, closing this knowledge gap is essential for the application of stable isotope approaches for partitioning ecosystem respiration, tracing carbon flow through plants and ecosystems and disentangling key physiological processes in carbon metabolism of plants. In this review we examine the short-term dynamics in δ13Cres and putative substrate pools at the plant, soil and ecosystem scales and develop mechanistic explanations for diel δ13Cres dynamics at each scale. Maximum reported variation in diel δ13Cres is 4.0, 5.4 and 14.8‰ in trunks, roots and leaves of different species and 12.5 and 8.1‰ at the soil and ecosystem scale in different biomes. Temporal variation in post-photosynthetic fractionation related to changes in carbon allocation to different metabolic pathways is the most plausible mechanistic explanation for observed diel dynamics in δ13Cres. In addition, mixing of component fluxes with different temporal dynamics and isotopic compositions add to the δ13Cres variation on the soil and ecosystem level. Understanding short-term variations in δ13Cres is particularly important for ecosystem studies, since δ13Cres contains information on the fate of respiratory substrates, and may, therefore, provide a non-intrusive way to identify changes in carbon allocation patterns.
Sedimentary organic matter variations in the Chukchi Borderland over the last 155 kyr
Authors: Rella S. F. , Uchida M.
Published: March 2011

Abstract. Knowledge on past variability of sedimentary organic carbon in the Arctic Ocean is important to assess natural carbon cycling and transport processes related to global climate changes. However, the late Pleistocene oceanographic history of the Arctic is still poorly understood. In the present study we show sedimentary records of total organic carbon (TOC), C/N and CaCO3 from a piston core recovered from the northern Northwind Ridge in the far western Arctic Ocean, a region potentially sensitively responding to past variability in surface current regimes and sedimentary processes such as coastal erosion. An age model based on correlation of our CaCO3 record with the benthic δ18O stack, supplemented by lithological constraints, suggests that the piston core records paleoenvironmental changes of the last 155 kyr. According to this age model, TOC and C/N show orbital-scale increases and decreases that can be respectively correlated to the waxing and waning of large ice sheets dominating the Eurasian Arctic, suggesting advection of fine suspended matter derived from glacial erosion to the Northwind Ridge by eastward flowing intermediate water and/or surface water and sea ice during cold episodes of the last two glacial-interglacial cycles. At millennial scales, increases in TOC and C/N appear to correlate to a suite of Dansgaard-Oeschger Stadials between 120 and 40 ka before present (BP) and thus seem to respond to abrupt northern hemispheric temperature changes. Between 65 and 40 ka BP, closures and openings of the Bering Strait could have additionally influenced TOC and C/N variability. CaCO3 content tends to anti-correlate with TOC and C/N on both orbital and millennial time scales, which we interpret as enhanced sediment advection from the carbonate-rich Canadian Arctic via an extended Beaufort Gyre during warm periods of the last two glacial-interglacial cycles and increased terrestrial organic carbon advection from the Siberian Arctic during cold periods when the Beaufort Gyre contracted. We propose that this pattern may be related to orbital- and millennial-scale variations of dominant atmospheric surface pressure systems expressed in mode shifts of the Arctic Oscillation.
The atmosphere-ocean general circulation model EMAC-MPIOM
Authors: Pozzer A. , Jöckel P. , Kern B. , Haak H.
Published: March 2011

Abstract. The ECHAM/MESSy Atmospheric Chemistry (EMAC) model is coupled to the ocean general circulation model MPIOM using the Modular Earth Submodel Sytem (MESSy) interface. MPIOM is operated as a MESSy submodel, thus the need of an external coupler is avoided. The coupling method is tested for different model configurations, proving to be very flexible in terms of parallel decomposition and very well load balanced. The run time performance analysis and the simulation results are compared to those of the COSMOS (Community earth System MOdelS) climate model, using the same configurations for the atmosphere and the ocean in both model systems. It is shown that our coupling method is, for the tested conditions, approximately 10% more efficient compared to the coupling based on the OASIS (Ocean Atmosphere Sea Ice Soil, version 3) coupler. The standard (CMIP3) climate model simulations performed with EMAC-MPIOM show that the results are comparable to those of other Atmosphere-Ocean General Circulation models.
Smooth regional estimation of low-flow indices: physiographical space based interpolation and top-kriging
Authors: Castiglioni S. , Castellarin A. , Montanari A. , Skøien J. O. , Laaha G. , Blöschl G.
Published: March 2011

Abstract. Recent studies highlight that spatial interpolation techniques of point data can be effectively applied to the problem of regionalization of hydrometric information. This study compares two innovative interpolation techniques for the prediction of low-flows in ungauged basins. The first one, named Physiographical-Space Based Interpolation (PSBI), performs the spatial interpolation of the desired streamflow index (e.g., annual streamflow, low-flow index, flood quantile, etc.) in the space of catchment descriptors. The second technique, named Topological kriging or Top-kriging, predicts the variable of interest along river networks taking both the area and nested nature of catchments into account. PSBI and Top-kriging are applied for the regionalization of Q355 (i.e., a low-flow index that indicates the streamflow that is equalled or exceeded 355 days in a year, on average) over a broad geographical region in central Italy, which contains 51 gauged catchments. The two techniques are cross-validated through a leave-one-out procedure at all available gauges and applied to a subregion to produce a continuous estimation of Q355 along the river network extracted from a 90m elevation model. The results of the study show that Top-kriging and PSBI present complementary features. Top-kriging outperforms PSBI at larger river branches while PSBI outperforms Top-kriging for headwater catchments. Overall, they have comparable performances (Nash-Sutcliffe efficiencies in cross-validation of 0.89 and 0.83, respectively). Both techniques provide plausible and accurate predictions of Q355 in ungauged basins and represent promising opportunities for regionalization of low-flows.
Self-potential investigations of a gravel bar in a restored river corridor
Authors: Linde N. , Doetsch J. , Jougnot D. , Genoni O. , Dürst Y. , Minsley B. J. , Vogt T. , Pasquale N. , Luster J.
Published: March 2011

Abstract. Self-potentials (SP) are sensitive to water fluxes and concentration gradients in both saturated and unsaturated geological media, but quantitative interpretations of SP field data may often be hindered by the superposition of different source contributions and time-varying electrode potentials. Self-potential mapping and close to two months of SP monitoring on a gravel bar were performed to investigate the origins of SP signals at a restored river section of the Thur River in northeastern Switzerland. The SP mapping and subsequent inversion of the data indicate that the SP sources are mainly located in the upper few meters in regions of soil cover rather than bare gravel. Wavelet analyses of the time-series indicate a strong, but non-linear influence of water table and water content variations, as well as rainfall intensity on the recorded SP signals. Modeling of the SP response with respect to an increase in the water table elevation and precipitation indicate that the distribution of soil properties in the vadose zone has a very strong influence. We conclude that the observed SP responses on the gravel bar are more complicated than previously proposed semi-empiric relationships between SP signals and hydraulic head or the thickness of the vadose zone. We suggest that future SP monitoring in restored river corridors should either focus on quantifying vadose zone processes by installing vertical profiles of closely spaced SP electrodes or by installing the electrodes within the river to avoid signals arising from vadose zone processes and time-varying electrochemical conditions in the vicinity of the electrodes.