bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomass Steam Gasification with In-Situ CO2 Capture for Enriched Hydrogen Gas Production: A Reaction Kinetics Modelling Approach
Authors: Inayat Abrar , Ahmad Murni M. , Yusup Suzana , Mutalib Mohamed Ibrahim Abdul
Published: August 2010

Due to energy and environmental issues, hydrogen has become a more attractive clean fuel. Furthermore, there is high interest in producing hydrogen from biomass with a view to sustainability. The thermochemical process for hydrogen production, i.e. gasification, is the focus of this work. This paper discusses the mathematical modeling of hydrogen production process via biomass steam gasification with calcium oxide as sorbent in a gasifier. A modelling framework consisting of kinetics models for char gasification, methanation, Boudouard, methane reforming, water gas shift and carbonation reactions to represent the gasification and CO2 adsorption in the gasifier, is developed and implemented in MATLAB. The scope of the work includes an investigation of the influence of the temperature, steam/biomass ratio and sorbent/biomass ratio on the amount of hydrogen produced, product gas compositions and carbon conversion. The importance of different reactions involved in the process is also discussed. It is observed that hydrogen production and carbon conversion increase with increasing temperature and steam/biomass ratio. The model predicts a maximum hydrogen mole fraction in the product gas of 0.81 occurring at 950 K, steam/biomass ratio of 3.0 and sorbent/biomass ratio of 1.0. In addition, at sorbent/biomass ratio of 1.52, purity of H2 can be increased to 0.98 mole fraction with all CO2 present in the system adsorbed.
Advances and Challenges in Protein-Ligand Docking
Authors: Huang Sheng-You , Zou Xiaoqin
Published: August 2010

Molecular docking is a widely-used computational tool for the study of molecular recognition, which aims to predict the binding mode and binding affinity of a complex formed by two or more constituent molecules with known structures. An important type of molecular docking is protein-ligand docking because of its therapeutic applications in modern structure-based drug design. Here, we review the recent advances of protein flexibility, ligand sampling, and scoring functions—the three important aspects in protein-ligand docking. Challenges and possible future directions are discussed in the Conclusion.
Political Economy, Capitalism and Sustainable Development
Authors: Liodakis George
Published: August 2010

After a critical review of conventional approaches to sustainability, this paper contrasts orthodox (neoclassical) economic theory with a political economy approach, arguing that such an approach focusing on the historically specific organizational form of production and the inherent characteristics of the capitalist mode of production is crucial for exploring the preconditions, the content and the prospects of sustainability. Analyzing briefly these characteristics and the developmental trends of capitalism, we locate the basic causes behind the currently exacerbated economic and ecological crisis, and on these grounds we briefly explore the required systemic transformations necessary to ensure a socially and ecologically, truly sustainable development.
Comments on ‘Straka, T.J.; Layton, P.A. Natural Resources Management: Life Cycle Assessment and Forest Certification and Sustainability Issues. Sustainability 2010, 2, 604–623’
Authors: Gunneberg Ben
Published: August 2010

Unreferenced statement on page 608: “A fundamental difference between FSC and PEFC is the stakeholders. While FSC was founded mainly by environmental groups, PEFC had strong forest industry and trade groups among its founders. This is one reason FSC is not a member of PEFC. Both the ATFS and SFI are recognized by PEFC as acceptable standards”.
Immune modulator and antiviral potential of dendritic cells pulsed with both hepatitis B surface antigen and core antigen for treating chronic HBV infection
Authors: Akbar Sheikh Mohammad Fazle , Yoshida Osamu , Chen Shiyi , Cesar Aguilar Julio , Abe Masanori , Matsuura Bunzo , Hiasa Yoichi , Onji Morikazu
Published: August 2010

Background

Commercially available prophylactic vaccines containing hepatitis B surface antigen (HBsAg), which are used to prevent HBV infections, are not as effective as a therapeutic immune modulator for treating patients with chronic hepatitis B (CHB). In this study, the immunogenicity of dendritic cells (DC) loaded with both HBsAg and hepatitis B core antigen (HBcAg) was tested in HBV transgenic mice (TM; 1.2HB-BS10) in vivo and in patients with CHB in vitro.

Methods

Spleen DC from HBV TM were cultured with a vaccine containing both HBsAg and HBcAg to produce HBsAg/HBcAg-pulsed DC. HBV TM were immunized twice at an interval of 4 weeks with HBsAg/HBcAg-pulsed DC and other immune modulators. Antibody titres to HBsAg (anti-HBs) were measured in sera. Antigen-specific T-cells and cytotoxic T-lymphocytes (CTLs) in the spleen and liver were detected by lymphoproliferative and ELISPOT assays, respectively. HBsAg/HBcAg-pulsed human blood DC were cultured with autologous T-cells from CHB patients to assess their antigen-specific immune modulatory capacities.

Results

Significantly higher levels of anti-HBs, HBsAg-specific and HBcAg-specific T-cells and CTLs were detected in the spleen and liver of HBV TM immunized with HBsAg/HBcAg-pulsed DC compared with those immunized with other vaccine formulations ( P<0.05). HBsAg/HBcAg-pulsed human blood DC also induced HBsAg- and HBcAg-specific proliferation of autologous T-cells from CHB patients.

Conclusions

The immune modulatory capacities of HBsAg/ HBcAg-pulsed DC in HBV TM in vivo, and in patients with CHB in vitro, inspire optimism about a clinical trial with this cell-based vaccine in patients with CHB.
Antiendothelial Cell Antibodies Induce Apoptosis of Bone Marrow Endothelial Progenitors in Systemic Sclerosis
Authors: DEL PAPA NICOLETTA , QUIRICI NADIA , SCAVULLO CINZIA , GIANELLI UMBERTO , CORTI LAURA , VITALI CLAUDIO , FERRI CLODOVEO , GIUGGIOLI DILIA , MANFREDI ANDREINA , MAGLIONE WANDA , ONIDA FRANCESCO , COLACI MICHELE , BOSARI SILVANO , LAMBERTENGHI DELILIERS GIORGIO
Published: August 2010

Objective.

Patients with systemic sclerosis (SSc) have significantly fewer and functionally impaired endothelial progenitor cells (EPC) in peripheral blood and bone marrow; further, endothelial apoptosis seems to play a primary role in the pathogenesis of vascular damage. We investigated whether the failure of bone marrow EPC is related to their apoptotic phenotype and analyzed the possible mechanisms inducing apoptosis.

Methods.

The presence of apoptotic cells was investigated in bone marrow aspirates taken from patients with SSc; microvessel density (MVD) and the immunohistochemical expression of vascular endothelial growth factor (VEGF) were also measured in bone marrow biopsies. A correlation between EPC apoptosis and the presence of antiendothelial cell antibodies (AECA) was also investigated.

Results.

We confirmed the presence of bone marrow EPC dysfunction in SSc, while hematopoiesis was not impaired. Bone marrow studies showed a high percentage of apoptotic progenitors, no signs of fibrosis or an altered MVD, and an increased VEGF index. The patients’ bone marrow plasma showed significant titers of AECA, and their presence correlated with that of apoptotic progenitors. These findings were further confirmed by anin vitroassay in which the apoptosis of normal progenitors was induced by the addition of AECA+ purified IgG.

Conclusion.

Our results showed that apoptosis in patients with SSc involves the source compartment of endothelial progenitors and correlates with AECA activity. These findings support the hypothesis that AECA may play a pathogenetic role by affecting the bone marrow EPC machinery that should repair the peripheral vascular lesions.
Assessment of Ankylosing Spondylitis Criteria in Patients with Chronic Low Back Pain and Vertebral Endplate Modic I Signal Changes
Authors: NGUYEN CHRISTELLE , BENDEDDOUCHE IMAD , SANCHEZ KATHERINE , JOUSSE MARYLÈNE , PAPELARD AGATHE , FEYDY ANTOINE , REVEL MICHEL , POIRAUDEAU SERGE , RANNOU FRANÇOIS
Published: August 2010

Objective.

Patients with chronic low back pain (cLBP) and vertebral endplate Modic I signal changes on lumbar magnetic resonance imaging (MRI) have clinical features that could mimic inflammatory back pain related to spondyloarthritis (SpA) and/or ankylosing spondylitis (AS). We aimed to assess whether such patients fulfilled criteria for SpA and/or AS.

Methods.

For 5 months in 2008, all patients (n = 314) referred to a tertiary care physical medicine and rehabilitation facility in France were consecutively screened. A total of 185 hospitalized for non-specific cLBP were prospectively assessed. Forty patients fulfilling inclusion criteria were consecutively enrolled and included in 2 groups according to MRI findings: Modic I (n = 15) and non-Modic I (n = 25). MRI findings were assessed independently by 2 spine specialists and a radiologist. HLA-B27 status was determined. Data were collected on clinical measurements and fulfillment of Amor criteria (AC) and modified New York criteria (mNYC). All assessors were blinded to HLA-B27 status.

Results.

Whatever the Modic group, no patient fulfilled AC or mNYC, and mean total scores were comparable [3 ± 2 (range 0–22; p = 0.977), 1 ± 1 (range 0–3; p = 1.000), and 0 ± 0 (range 0–1; p = 1.000) for AC and clinical and radiological mNYC, respectively]. HLA-B27 status was similar in both groups [n = 2 (13%) vs n = 0 (0%); p = 0.135].

Conclusion.

Patients with cLBP and Modic I vertebral endplate signal changes on lumbar MRI do not fulfill widely used and validated criteria for SpA and/or AS. Such cases are clinically distinct from SpA and AS.
Probiotic Therapy for the Treatment of Spondyloarthritis: A Randomized Controlled Trial
Authors: JENKS KATHERINE , STEBBINGS SIMON , BURTON JEREMY , SCHULTZ MICHAEL , HERBISON PETER , HIGHTON JOHN
Published: August 2010

Objective.

To investigate the effect of an orally administered probiotic on disease activity, fatigue, quality of life, and intestinal symptoms in patients with active spondyloarthritis.

Methods.

Patients with active spondyloarthritis [defined as Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ≥ 3, Bath Ankylosing Spondylitis Functional Index (BASFI) ≥ 3, Maastricht Ankylosing Spondylitis Enthesitis Score (MASES) ≥ 2, or peripheral joint count ≥ 2] were randomized to oral probiotic or placebo for 12 weeks. Patients and assessors were blinded to treatment allocation. The primary outcome measure was 10% improvement in the BASFI. Additional outcome measures were improvements in the ASsessments in Ankylosing Spondylitis (ASAS)-endorsed core domains: pain, spinal mobility, patient global, peripheral joint and entheseal scores, stiffness, C-reactive protein, and fatigue. The ASAS20 criteria, a composite measure of response, were also applied. Quality of life and bowel symptoms were quantified using the Ankylosing Spondylitis Quality of Life Questionnaire (ASQoL) and Dudley Inflammatory Bowel Symptom Questionnaire (DISQ).

Results.

Sixty-three patients were randomized to oral probiotic (n = 32) or placebo (n = 31). All patients completed the trial. No significant difference was noted between groups in any of the core domains. The mean BASFI fell from 3.5 ± 2.0 to 2.9 ± 1.9 in the probiotic group and from 3.6 ± 1.9 to 3.1 ± 2.2 in the placebo group (p = 0.839). The mean BASDAI fell from 4.2 ± 2.2 to 3.2 ± 2.1 in the probiotic group and 4.5 ± 2.0 to 3.9 ± 2.2 in the placebo group (p = 0.182). No significant adverse events were recorded in the probiotic-treated group.

Conclusion.

In this randomized controlled trial, the probiotic combination administered did not demonstrate significant benefit over placebo, despite a theoretical rationale for this therapy.
La vidéosurveillance dans les lycées
Authors: Le Goff Tanguy
Published: August 2010

Pour lutter contre les « violences scolaires », les établissements scolaires sont désormais fréquemment équipés d’une vidéosurveillance. Pourquoi et comment des proviseurs font-ils le choix de ce type de réponse technique ? Quels en sont les usages concrets ? Quels sont les impacts de l’introduction de cette technologique sur la communauté éducative ? L’article entend répondre à ces questions en s’appuyant sur une enquête réalisée dans 10 lycées franciliens auprès de la communauté éducative et de lycéens. Elle met en évidence qu’au-delà des finalités affichées de prévention des « intrusions », la vidéosurveillance est en fait bien souvent utilisée comme un outil au service d’une politique de maintien de l’ordre scolaire.
Severe Relapsing Goodpasture's Disease Successfully Treated with Mycophenolate Mofetil
Authors: Malho Anabela , Santos Viriato , Cabrita Ana , Silva Ana Paula , Pinto Isabel , Bernardo Idalécio , Neves Pedro Leão
Published: August 2010

Goodpasture's disease is a rare autoimmune disorder characterised by the development of antiglomerular basement membrane autoantibodies, which typically presents with rapidly progressive crescentic glomerulonephritis and pulmonary haemorrhage. Even with aggressive nonspecific immunosuppression and plasma exchange, mortality remains high. We report a case of life-threatening Goodpasture's disease with relapsing pulmonary haemorrhage refractory to conventional therapy. Second line treatment was based on mycophenolate mofetil 1 g every 12 hours and prednisolone 60 mg/day. In this case, the use of a low-dose mycophenolate mofetil regimen turned out to be insufficient. However, in our opinion higher mycophenolate mofetil doses should be considered an alternative treatment, mainly in relapsing disease, due to its mechanism of action and current insufficient therapeutic weapons.
Knowledge management in local government: The case of Stellenbosch Municipality
Authors: Gaffoor Shamin , Cloete Fanie
Published: August 2010

Knowledge management (KM) was a well-founded management approach that held significant benefits for public sector organisations. KM as a management philosophy had an impact on various components of an organisation and it could therefore significantly advance organisational efficiency. The successful implementation of KM initiatives had to be ensured because, different organisational processes and departments had to collaborate and functional silos had to be eliminated. KM required long-term commitment and dedication from all organisational members. Furthermore, there were certain knowledge management enablers in an organisation that needed to be developed and that were necessary for the achievement of organisational effectiveness. These enablers were the organisational culture, human resources, information technology, organisational structure and, the organisation’s strategy and leadership. This article assessed each of these enablers and how they impacted on an organisation’s KM efforts. Stellenbosch Municipality was used as a case in point. The article further examined how local governments were able to effectively implement KM practices as strategic tools used to achieve service delivery and operational goals. The article concluded with a number of recommended strategies, (1) to develop the KM enablers that were present in organisations and (2) to aid the implementation of successful organisational KM initiatives.
Transport of North African dust from the Bodélé depression to the Amazon Basin: a case study
Authors: Ben-Ami Y. , Koren I. , Rudich Y. , Artaxo P. , Martin S. T. , Andreae M. O.
Published: August 2010

Abstract. Through long-range transport of dust, the North-African desert supplies essential minerals to the Amazon rain forest. Since North African dust reaches South America mostly during the Northern Hemisphere winter, the dust sources active during winter are the main contributors to the forest. Given that the Bodélé depression area in southwestern Chad is the main winter dust source, a close link is expected between the Bodélé emission patterns and volumes and the mineral supply flux to the Amazon. Until now, the particular link between the Bodélé and the Amazon forest was based on sparse satellite measurements and modeling studies. In this study, we combine a detailed analysis of space-borne and ground data with reanalysis model data and surface measurements taken in the central Amazon during the Amazonian Aerosol Characterization Experiment (AMAZE-08) in order to explore the validity and the nature of the proposed link between the Bodélé depression and the Amazon forest. This case study follows the dust events of 11–16 and 18–27 February 2008, from the emission in the Bodélé over West Africa (most likely with contribution from other dust sources in the region) the crossing of the Atlantic Ocean, to the observed effects above the Amazon canopy about 10 days after the emission. The dust was lifted by surface winds stronger than 14 m s−1, usually starting early in the morning. The lofted dust, mixed with biomass burning aerosols over Nigeria, was transported over the Atlantic Ocean, and arrived over the South American continent. The top of the aerosol layer reached above 3 km, and the bottom merged with the boundary layer. The arrival of the dusty air parcel over the Amazon forest increased the average concentration of aerosol crustal elements by an order of magnitude.
Introducing the bromide/alkalinity ratio for a follow-up discussion on "Precipitation of salts in freezing seawater and ozone depletion events: a status report", by Morin et al., published in Atmos. Chem. Phys., 8, 7317–7324, 2008
Authors: Sander R. , Morin S.
Published: August 2010

Abstract. Sander et al. (2006) proposed that CaCO3 precipitation can be an important factor in triggering tropospheric ozone depletion events. Recently, Morin et al. (2008b) presented calculations with the FREZCHEM model and concluded that their results and interpretation cast doubt on the validity of this hypothesis. In this joint publication, we have re-analyzed the implications of the FREZCHEM results and show how they can be reconciled with the proposal of Sander et al. (2006). The chemical predictions of both approaches are consistent. Although an interpretation solely based on the alkalinity change in the brine does not support the conclusion of Sander et al. (2006), we show that the bromide/alkalinity ratio (which increases during the cooling of the brine) can be used as an indicator of the potential for triggering bromine explosions.
CO2 column-averaged volume mixing ratio derived over Tsukuba from measurements by commercial airlines
Authors: Araki M. , Morino I. , Machida T. , Sawa Y. , Matsueda H. , Ohyama H. , Yokota T. , Uchino O.
Published: August 2010

Abstract. Column-averaged volume mixing ratios of carbon dioxide (XCO2) during the period from January 2007 to May 2008 over Tsukuba, Japan, were derived using CO2 concentrations measured by Continuous CO2 Measuring Equipment (CME). The CMEs were installed on Japan Airlines Corporation (JAL) commercial airliners, which frequently fly to and from Narita Airport. It was assumed that CO2 profiles over Tsukuba and Narita are the same. CO2 profile data for 493 flights on clear-sky days were analyzed in order to calculate XCO2 with one of two ancillary datasets: "Tsukuba observational" data (rawinsonde and meteorological tower), or "global" forecast/reanalysis and climatological data (NCEP and CIRA-86). The amplitude of the seasonal variation of XCO2 using the ancillary data measured in Tsukuba (XCO2 (Tsukuba observational)) was determined by a least squares fit using a harmonic function to roughly evaluate the seasonal variation over Tsukuba. The highest and lowest values of the obtained fitted curve in 2007 for XCO2 (Tsukuba observational) were 386.4 ± 1.0 and 381.7 ± 1.0 ppm in May and September, respectively, where the errors represent 1 standard deviation of the fit residuals. The dependence of XCO2 on the type of ancillary dataset was evaluated. The average difference between XCO2 from global climatological data, XCO2 (global), and XCO2 (Tsukuba observational), i.e., the bias of XCO2 (global) based on XCO2 (Tsukuba observational), was found to be −0.621 ppm with a standard deviation of 0.682 ppm. The uncertainty of XCO2 (global) based on XCO2 (Tsukuba observational) was estimated to be 0.922 ppm. This small uncertainty relative to the GOSAT precision suggests that calculating XCO2 using data from airliners and global climatological data can be applied to the validation of GOSAT products for XCO2 over airports worldwide.
Black carbon semi-direct effects on cloud cover: review and synthesis
Authors: Koch D. , Del Genio A. D.
Published: August 2010

Abstract. Absorbing aerosols (AAs) such as black carbon (BC) or dust absorb incoming solar radiation, perturb the temperature structure of the atmosphere, and influence cloud cover. Previous studies have described conditions under which AAs either increase or decrease cloud cover. The effect depends on several factors, including the altitude of the AA relative to the cloud and the cloud type. We attempt to categorize the effects into several likely regimes. Cloud cover is decreased if the AAs are embedded in the cloud layer. AAs below cloud may enhance convection and cloud cover. AAs above cloud top stabilize the underlying layer and tend to enhance stratocumulus clouds but may reduce cumulus clouds. AAs can also promote cloud cover in convergent regions as they enhance deep convection and low level convergence as it draws in moisture from ocean to land regions. Most global model studies indicate a regional variation in the cloud response but generally increased cloud cover over oceans and some land regions, with net increased low-level and/or reduced upper level cloud cover. The result is a net negative semi-direct effect feedback from the cloud response to AAs. In some of these climate model studies, the cooling effect of BC due to cloud changes is strong enough to essentially cancel the warming direct effects.
Options to accelerate ozone recovery: ozone and climate benefits
Authors: Daniel J. S. , Fleming E. L. , Portmann R. W. , Velders G. J. M. , Jackman C. H. , Ravishankara A. R.
Published: August 2010

Abstract. Hypothetical reductions in future emissions of ozone-depleting substances (ODSs) and N2O are evaluated in terms of effects on equivalent effective stratospheric chlorine (EESC), globally-averaged total column ozone, and radiative forcing through 2100. Due to the established success of the Montreal Protocol, these actions can have only a fraction of the impact on ozone depletion that regulations already in force have had. If all anthropogenic ODS and N2O emissions were halted beginning in 2011, ozone is calculated to be higher by about 1–2% during the period 2030–2100 compared to a case of no additional restrictions. Direct radiative forcing by 2100 would be about 0.23 W/m2 lower from the elimination of anthropogenic N2O emissions and about 0.005 W/m2 lower from the destruction of the chlorofluorocarbon (CFC) bank. Due to the potential impact of N2O on future ozone levels, we provide an approach to incorporate it into the EESC formulation, which is used extensively in ozone depletion analyses. The ability of EESC to describe total ozone changes arising from additional ODS and N2O controls is also quantified.
Manchester Ice Nucleus Counter (MINC) measurements from the 2007 International workshop on Comparing Ice nucleation Measuring Systems (ICIS-2007)
Authors: Jones H. M. , Flynn M. J. , DeMott P. J. , Möhler O.
Published: August 2010

Abstract. An ice nucleus counter was developed and constructed to enable investigation of potential ice nucleating materials. The Manchester Ice Nucleus Chamber (MINC) is a concentric-cylinder continuous flow diffusion chamber (CFDC). A full explanation of the MINC instrument is given here, along with first results and a comparison to an established instrument of similar design (Colorado State University CFDC) during sampling of common ice nucleating aerosols at the 2007 International workshop on Comparing Ice nucleation Measuring Systems (ICIS-2007). Both instruments detected the onset of ice nucleation under similar conditions of temperature and supersaturation for several different types of ice nuclei. Comparisons of the ratio of ice nuclei to total aerosol concentrations as a function of relative humidity (RH) showed agreement within one order of magnitude. Possible reasons for differences between the two instruments relating to differences in their design are discussed, along with suggestions to future improvements to the current design.
Relating hygroscopicity and composition of organic aerosol particulate matter
Authors: Duplissy J. , DeCarlo P. F. , Dommen J. , Alfarra M. R. , Metzger A. , Barmpadimos I. , Prevot A. S. H. , Weingartner E. , Tritscher T. , Gysel M. , Aiken A. C. , Jimenez J. L. , Canagaratna M. R. , Worsnop D. R. , Collins D. R. , Tomlinson J. , Baltensperger U.
Published: August 2010

Abstract. A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f44). m/z 44 is due mostly to the ion fragment CO2+ for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfraujoch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation between the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic growth factor (GF) or "κorg" parameter, and f44 was determined and is given by κorg=2.2×f44−0.13. This approximation can be further verified and refined as the database for AMS and HTDMA measurements is constantly being expanded around the world. The use of this approximation could introduce an important simplification in the parameterization of hygroscopicity of OA in atmospheric models, since f44 is correlated with the photochemical age of an air mass.
Investigations of the impact of natural dust aerosol on cold cloud formation
Authors: Koehler K. A. , Kreidenweis S. M. , DeMott P. J. , Petters M. D. , Prenni A. J. , Möhler O.
Published: August 2010

Abstract. Dust particles represent a dominant source of particulate matter (by mass) to the atmosphere, and their emission from some source regions has been shown to be transported on regional and hemispherical scales. Dust particles' potential to interact with water vapor in the atmosphere can lead to important radiative impacts on the climate system, both direct and indirect. We have investigated this interaction for several types of dust aerosol, collected from the Southwestern United States and the Saharan region. A continuous flow diffusion chamber was operated to measure the ice nucleation ability of the dust particles in the temperature range of relevance to cirrus and mixed-phase clouds (−65
Observations of ice multiplication in a weakly convective cell embedded in supercooled mid-level stratus
Authors: Crosier J. , Bower K. N. , Choularton T. W. , Westbrook C. D. , Connolly P. J. , Cui Z. Q. , Crawford I. P. , Capes G. L. , Coe H. , Dorsey J. R. , Williams P. I. , Illingworth A. J. , Gallagher M. W. , Blyth A. M.
Published: August 2010

Abstract. Simultaneous observations of cloud microphysical properties were obtained by in-situ aircraft measurements and ground based Radar/Lidar. Widespread mid-level stratus cloud was present below a temperature inversion (~5 °C magnitude) at 3.6 km altitude. Localised convection (peak updraft 1.5 m s−1) was observed 20 km west of the Radar station. This was associated with convergence at 2.5 km altitude. The convection was unable to penetrate the inversion capping the mid-level stratus. The mid-level stratus cloud was vertically thin (~400 m), horizontally extensive (covering 100 s of km) and persisted for more than 24 h. The cloud consisted of supercooled water droplets and small concentrations of large (~1 mm) stellar/plate like ice which slowly precipitated out. This ice was nucleated at temperatures greater than −12.2 °C and less than −10.0 °C, (cloud top and cloud base temperatures, respectively). No ice seeding from above the cloud layer was observed. This ice was formed by primary nucleation, either through the entrainment of efficient ice nuclei from above/below cloud, or by the slow stochastic activation of immersion freezing ice nuclei contained within the supercooled drops. Above cloud top significant concentrations of sub-micron aerosol were observed and consisted of a mixture of sulphate and carbonaceous material, a potential source of ice nuclei. Precipitation from the mid-level stratus evaporated before reaching the surface, whereas rates of up to 1 mm h−1 were observed below the convective feature. There is strong evidence for the Hallett-Mossop (HM) process of secondary ice particle production leading to the formation of the precipitation observed. This includes (1) Ice concentrations in the convective feature were more than an order of magnitude greater than the concentration of primary ice in the overlaying stratus, (2) Large concentrations of small pristine columns were observed at the ~−5 °C level together with liquid water droplets and a few rimed ice particles, (3) Columns were larger and increasingly rimed at colder temperatures. Calculated ice splinter production rates are consistent with observed concentrations if the condition that only droplets greater than 24 μm are capable of generating secondary ice splinters is relaxed. This case demonstrates the importance of understanding the formation of ice at slightly supercooled temperatures, as it can lead to secondary ice production and the formation of precipitation in clouds which may not otherwise be considered as significant precipitation sources.
Fine-scale turbulence soundings in the stratosphere with the new balloon-borne instrument LITOS
Authors: Theuerkauf A. , Gerding M. , Lübken F.-J.
Published: August 2010

Abstract. We have developed a new compact balloon payload called LITOS (Leibniz-Institute Turbulence Observations in the Stratosphere) for high resolution wind turbulence soundings up to 35 km altitude. The wind measurements are performed applying a constant temperature anemometer (CTA) with a vertical resolution of ~2.5 mm, i.e. 2 kHz sampling rate at 5 m/s ascent speed. Thereby, for the first time, it is possible to study the entire turbulence spectrum down to the viscous subrange in the stratosphere. Including telemetry, housekeeping, batteries and recovery unit the payload weighs less than 5 kg and can be launched at any radiosonde station. Since autumn 2007 LITOS has been successfully launched several times from the Leibniz-Institute of Atmospheric Physics (IAP) in Kühlungsborn, Germany (54° N, 12° E). Two additional soundings were carried out in 2008 and 2009 at Kiruna, Sweden (67° N, 21° E) as part of the BEXUS program (Balloon-borne EXperiments for University Students). We describe here the basic principle of CTA measurements and prove the validity of this method in the stratosphere. First case studies allow a clear distinction between non-turbulent layers and turbulent layers with a thickness of some tens of meters. Since our measurements cover the transition between the inertial and viscous subrange, energy dissipation rates can be calculated with high reliability.
Retrieval of dust aerosols during night: improved assessment of long wave dust radiative forcing over Afro-Asian regions
Authors: Deepshikha S. , Srinivasan J.
Published: August 2010

Abstract. Several investigators in the past have used the radiance depression (with respect to clear-sky infrared radiance), resulting from the presence of mineral dust aerosols in the atmosphere, as an index of dust aerosol load in the atmosphere during local noon. Here, we have used a modified approach to retrieve dust index during night since assessment of diurnal average infrared dust forcing essentially requires information on dust aerosols during night. For this purpose, we used infrared radiance (10.5–12.5 μm), acquired from the METEOSAT-5 satellite (~ 5 km resolution). We found that the "dust index" algorithm, valid for daytime, will no longer hold during the night because dust is then hotter than the theoretical dust-free reference. Hence we followed a "minimum reference" approach instead of a conventional "maximum reference" approach. A detailed analysis suggests that the maximum dust load occurs during the daytime. Over the desert regions of India and Africa, maximum change in dust load is as much as a factor of four between day and night and factor of two variations are commonly observed. By realizing the consequent impact on long wave dust forcing, sensitivity studies were carried out, which indicate that utilizing day time data for estimating the diurnally averaged long-wave dust radiative forcing results in significant errors (as much as 50 to 70%). Annually and regionally averaged long wave dust radiative forcing (which account for the diurnal variation of dust) at the top of the atmosphere over Afro-Asian region is 2.6 ± 1.8 W m−2, which is 30 to 50% lower than those reported earlier. Our studies indicate that neglecting diurnal variation of dust while assessing its radiative impact leads to an overestimation of dust radiative forcing, which in turn result in underestimation of the radiative impact of anthropogenic aerosols.
The trophic biology of the holothurian Molpadia musculus: implications for organic matter cycling and ecosystem functioning in a deep submarine canyon
Authors: Amaro T. , Bianchelli S. , Billett D. S. M. , Cunha M. R. , Pusceddu A. , Danovaro R.
Published: August 2010

Abstract. Megafaunal organisms play a key role in ecosystem functioning in the deep-sea through bioturbation, bioirrigation and organic matter cycling. At 3500 m water depth in the Nazaré Canyon, NE Atlantic, very high abundances of the infaunal holothurian Molpadia musculus were observed. To quantify the role of M. musculus in sediment cycling, sediment samples and holothurians were collected using an ROV and in situ experiments were conducted with incubation chambers. The biochemical composition of the sediment (in terms of proteins, carbohydrates and lipids), the holothurians' gut contents and holothurians' faecal material were analysed. In the sediments, proteins were the dominant organic compound, followed by carbohydrates and lipids. In the holothurian's gut contents, protein concentrations were higher than the other compounds, decreasing significantly as the material passed through the digestive tract. Approximately 33±1% of the proteins were digested by the time sediment reached the mid gut, with a total digestion rate equal to 67±1%. Carbohydrates and lipids were ingested in smaller amounts and digested with lower efficiencies (23±11% and 50±11%, respectively). As a result, the biopolymeric C digestion rate was on average 62±3%. We estimated that the population of M. musculus could remove approximately 0.49±0.13 g biopolymeric C and 0.13±0.03 g N m−2 d−1 from the sediments. These results suggest that M. musculus plays a key role in the benthic tropho-dynamics and biogeochemical processes in the Nazaré Canyon.
Shadow analysis of soil surface roughness compared to the chain set method and direct measurement of micro-relief
Authors: García Moreno R. , Díaz Álvarez M. C. , Tarquis A. M. , Paz González A. , Saa Requejo A.
Published: August 2010

Abstract. Soil surface roughness (SSR) expresses soil susceptibility to wind and water erosion and plays an important role in the development and the maintenance of soil biota. Several methods have been developed to characterise SSR based on different methods of acquiring data. Because the main problems related to these methods involve the use and handling of equipment in the field, the present study aims to fill the need for a method for measuring SSR that is more reliable, low-cost and convenient in the field than traditional field methods. Shadow analysis, which interprets micro-topographic shadows, is based on the principle that there is a direct relationship between the soil surface roughness and the shadows cast by soil structures under fixed sunlight conditions. SSR was calculated with shadows analysis in the laboratory using hemispheres of different diameter with a diverse distribution of known altitudes and a surface area of 1 m2. Data obtained from the shadow analysis were compared to data obtained with the chain method and simulation of the micro-relief. The results show a relationship among the SSR calculated using the different methods. To further improve the method, shadow analysis was used to measure the SSR in a sandy clay loam field using different tillage tools (chisel, tiller and roller) and in a control of 4 m2 surface plots divided into subplots of 1 m2. The measurements were compared to the data obtained using the chain set and pin meter methods. The SSR measured was the highest when the chisel was used, followed by the tiller and the roller, and finally the control, for each of the three methods. Shadow analysis is shown to be a reliable method that does not disturb the measured surface, is easy to handle and analyse, and shortens the time involved in field operations by a factor ranging from 4 to 20 compared to well known techniques such as the chain set and pin meter methods.
Litter quality and pH are strong drivers of carbon turnover and distribution in alpine grassland soils
Authors: Budge K. , Leifeld J. , Hiltbrunner E. , Fuhrer J.
Published: August 2010

Abstract. Alpine soils are expected to contain large amounts of labile carbon (C) which may become a further source of atmospheric CO2 as a of global warming. However, there is little data available on these soils, and understanding of the influence of environmental factors on soil organic matter (SOM) turnover is limited. We extracted 30 cm deep cores from five grassland sites along a small elevation gradient from 2285 to 2653 m above sea level (a.s.l.) in the central Swiss Alps. Our aim was to determine the quantity, degree of stabilization and mean residence time (MRT) of SOM in relation to site factors such as temperature, soil pH, vegetation, and organic matter (OM) structure. Soil fractions obtained by size and density fractionation revealed a high proportion of labile particulate organic matter C (POM C %) mostly in the uppermost soil layers. POM C in the top 20 cm across the gradient ranged from 39.6–57.6% in comparison to 7.2–29.6% reported in previous studies for lower elevation soils (810–1960 m a.s.l.). At the highest elevation, MRTs measured by means of radiocarbon dating and turnover modelling, increased between fractions of growing stability from 90 years in free POM (fPOM) to 534 years in the mineral-associated fraction (mOM). Depending on elevation and pH, plant community data indicated considerable variation in the quantity and quality of litter input, and these patterns could be reflected in the dynamics of soil C. 13C NMR data confirmed the direct relationship of OM composition to MRT. While temperature is likely to be a major cause for the slow turnover rate observed, other factors such as litter quality and soil pH, as well as the combination of all factors, play an important role in causing small-scale variability of SOM turnover. Ignoring this interplay of controlling factors may impair the performance of models to project SOM responses to environmental change.
A method for parameterising roughness and topographic sub-grid scale effects in hydraulic modelling from LiDAR data
Authors: Casas A. , Lane S. N. , Yu D. , Benito G.
Published: August 2010

Abstract. High resolution airborne laser data provide new ways to explore the role of topographic complexity in hydraulic modelling parameterisation, taking into account the scale-dependency between roughness and topography. In this paper, a complex topography from LiDAR is processed using a spatially and temporally distributed method at a fine resolution. The surface topographic parameterisation considers the sub-grid LiDAR data points above and below a reference DEM, hereafter named as topographic content. A method for roughness parameterisation is developed based on the topographic content included in the topographic DEM. Five subscale parameterisation schemes are generated (topographic contents at 0, ±5, ±10, ±25 and ±50 cm) and roughness values are calculated using an equation based on the mixing layer theory (Katul et al., 2002), resulting in a co-varied relationship between roughness height and topographic content. Variations in simulated flow across spatial subscales show that the sub grid-scale behaviour of the 2-D model is not well-reflected in the topographic content of the DEM and that subscale parameterisation must be modelled through a spatially distributed roughness parameterisation. Variations in flow predictions are related to variations in the roughness parameter. Flow depth-derived results do not change systematically with variation in roughness height or topographic content but they respond to their interaction. Finally, subscale parameterisation modifies primarily the spatial structure (level of organisation) of simulated 2-D flow linearly with the additional complexity of subscale parameterisation.
Process-based distributed modeling approach for analysis of sediment dynamics in a river basin
Authors: Kabir M. A. , Dutta D. , Hironaka S.
Published: August 2010

Abstract. Modeling of sediment dynamics for developing best management practices of reducing soil erosion and of sediment control has become essential for sustainable management of watersheds. Precise estimation of sediment dynamics is very important since soils are a major component of enormous environmental processes and sediment transport controls lake and river pollution extensively. Different hydrological processes govern sediment dynamics in a river basin, which are highly variable in spatial and temporal scales. This paper presents a process-based distributed modeling approach for analysis of sediment dynamics at river basin scale by integrating sediment processes (soil erosion, sediment transport and deposition) with an existing process-based distributed hydrological model. In this modeling approach, the watershed is divided into an array of homogeneous grids to capture the catchment spatial heterogeneity. Hillslope and river sediment dynamic processes have been modeled separately and linked to each other consistently. Water flow and sediment transport at different surface grids and river nodes are modeled using one-dimensional kinematic wave approximation of Saint-Venant equations. The mechanics of sediment dynamics are integrated into the model using representative physical equations after a comprehensive review. The model has been tested on river basins in two different hydro climatic areas, the Abukuma River Basin, Japan and Latrobe River Basin, Australia. Sediment transport and deposition are modeled using Govers transport capacity equation. All spatial datasets, such as, Digital Elevation Model (DEM), land use and soil classification data, etc., have been prepared using raster "Geographic Information System (GIS)" tools. The results of relevant statistical checks (Nash-Sutcliffe efficiency and R-squared value) indicate that the model simulates basin hydrology and its associated sediment dynamics reasonably well. This paper presents the model including descriptions of the various components and the results of its application on case study areas.
Uncertainty in water resources availability in the Okavango River Basin as a result of climate change
Authors: Hughes D. A. , Kingston D. G. , Todd M. C.
Published: August 2010

Abstract. This paper assesses the hydrological response to scenarios of climate change in the Okavango River catchment in Southern Africa. Climate scenarios are constructed representing different changes in global mean temperature from an ensemble of 7 climate models assessed in the IPCC AR4. The results show a substantial change in mean flow associated with a global warming of 2 °C. However, there is considerable uncertainty in the sign and magnitude of the projected changes between different climate models, implying that the ensemble mean is not an appropriate generalised indicator of impact. The uncertainty in response between different climate model patterns is considerably greater than the range due to uncertainty in hydrological model parameterisation. There is also a clear need to evaluate the physical mechanisms associated with the model projected changes in this region. The implications for water resource management policy are considered.
On the application of kinematic models to simulate the diffusive processes of debris flows
Authors: Arattano M. , Franzi L.
Published: August 2010

Abstract. Debris flows generally propagate along steep mountain torrents with dynamics primarily governed by gravitational and frictional forces. Thus, debris flows modelling can be successfully performed through the application of kinematic models, which consider only the effects of slope and friction and neglect the remaining terms of the momentum equation. However, the diffusion processes that can be observed in the field, such as the spreading of the debris flow wave as it flows downstream, can not be theoretically predicted by kinematic models, since diffusion is a second-order process neglected in the kinematic approximation. In this paper, this issue is discussed and an application for both a generalized diffusion wave model and a kinematic model is proposed of a debris flow which occurred in an Italian instrumented torrent to identify, in a real case scenario, the effective value of the neglected terms in the kinematic approximation.
A statistical model for sea surface diurnal warming driven by numerical weather prediction fluxes and winds
Authors: Filipiak M. J. , Merchant C. J. , Kettle H. , Le Borgne P.
Published: August 2010

Abstract. A statistical model is derived relating the diurnal variation of sea surface temperature (SST) to the net surface heat flux and surface wind speed from a numerical weather prediction (NWP) model. The model is derived using fluxes and winds from the European Centre for Medium-Range Weather Forecasting (ECMWF) NWP model and SSTs from the Spinning Enhanced Visible and Infrared Imager (SEVIRI). In the model, diurnal warming has a linear dependence on the net surface heat flux integrated since (approximately) dawn and an inverse quadratic dependence on the maximum of the surface wind speed in the same period. The model coefficients are found by matching, for a given integrated heat flux, the frequency distributions of the maximum wind speed deceedance and the observed warming exceedance. Diurnal cooling, where it occurs, is modelled as proportional to the integrated heat efflux divided by the heat capacity of the seasonal mixed layer. The model reproduces the statistics (mean, standard deviation, and 95-percentile) of the diurnal variation of SST seen by SEVIRI and reproduces the geographical pattern of mean warming seen by the Advanced Microwave Scanning Radiometer (AMSR-E). We use the functional dependencies in the statistical model to test the behaviour of two physical model of diurnal warming that display contrasting systematic errors.