bluuebunny/crossref_metadata_2025 huggingface dataset:
La certification scolaire de la diversité. Étude d'un dispositif de formation dans une grande école de journalisme
Authors: Tasset Cyprien
Published: May 2011

Résumé Pour diversifier l’accès au métier et contribuer à la démocratisation de l’enseignement supérieur, une école de journalisme a créé une filière par apprentissage offrant le même diplôme que sa formation classique. L’enquête de l’auteur (2006-2007) reconstitue la construction du dispositif, observe les épreuves de sélection puis décrit le travail de “confirmation” (Boltanski 2009) mené par l’encadrement et les apprentis pour résorber leurs doutes sur cette voie nouvelle. L’école avance une norme civique d’équité sociale mais la sélection se heurte aux ambiguïtés de la notion de diversité, aux tensions entre mérite et diversification. Face à la concentration de minorités visibles dans leur classe, les apprentis s’interrogent sur le poids de l’ethnicité dans leur recrutement. La figure de la discrimination positive stabilise les doutes qui entourent l’apprentissage, qui acquiert sa légitimité par la réévaluation des qualités acquises ou révélées dans la pratique aux dépens des compétences scolaires mesurées par le concours. Comme si, la dépendance des hiérarchies scolaires aux hiérarchies sociales étant avérée, l’entreprise était le seul acteur à même de promouvoir une méritocratie socialement équitable.
La démocratisation des contenus d'enseignement de l'école publique en Pologne : essai d'analyse des justifications politiques des réformes scolaires à la sortie du communisme
Authors: Urbanski Sébastien
Published: May 2011

Résumé En Pologne, en 1989, le monopole étatique dans la définition des contenus d’enseignement a été aboli. Cependant, la très grande liberté donnée aux auteurs des manuels et des programmes scolaires est aujourd’hui partiellement remise en question par de nombreux pédagogues. Cette liberté pose en particulier un problème de laïcité, dans la mesure où elle permet l’intrusion de croyances personnelles –notamment religieuses– dans ce qui est, officiellement, un enseignement universel. Cet article essaie d’expliquer les conditions de l’émergence de la loi sur l’école (1991), à l’origine de ces modalités de conception des contenus d’enseignement, en montrant qu’elle a été adoptée par les députés sur la base d’une convergence entre la critique marchande et la critique domestique de l’ancien système scolaire. L’article tente aussi d’identifier des ressources argumentaires identitaires, dont la présence est explicable par le processus de décomposition du mouvement social Solidarité.
Comment intégrer le développement durable à la stratégie?
Authors: Poisson-de Haro Serge
Published: May 2011

Résumé De nombreuses organisations ont décidé de transformer leurs processus dans l’optique du développement durable en prenant en compte non seulement les effets économiques de leurs activités, mais aussi leurs effets sociaux et environnementaux. Toutefois, pour la plupart des entreprises, il reste un long chemin à parcourir afin de faire vraiment du développement durable, car elles n’ont pas encore changé leurs façons de faire par manque de moyens, de savoir-faire ou de volonté. Comment les entreprises peuvent-elles se positionner, puis mettre en œuvre des plans d’action en matière de développement durable? Quel type de changement devraient-elles apporter? Cet article vise à aider les entreprises à mieux comprendre les enjeux du développement durable et à proposer une démarche cohérente par rapport à leurs ambitions stratégiques. Nous présentons les trois étapes de l’intégration du développement durable : analyser la performance économique, environnementale et sociale de l’entreprise; évaluer les enjeux du développement durable pour l’entreprise et l’industrie; adopter une position face au développement durable accordée avec l’importance de ce défi pour l’entreprise et sa capacité à le gérer. Plusieurs exemples illustrent nos propos. En outre, notre analyse de l’intégration du développement durable dans l’industrie de l’électricité en Espagne nous amène à constater que, dans un même secteur, des entreprises peuvent adopter un positionnement qui leur est propre.
Epidemiological Analysis of an Outbreak of Diffuse Lamellar Keratitis
Authors: Javaloy Jaime , Alió Jorge L. , Rodríguez Alejandra , González Amagoia , Pérez-Santonja Juan J.
Published: May 2011

Purpose:

To describe the incidence, causes, risk factors, and preventive strategies regarding an outbreak of diffuse lamellar keratitis (DLK).

Methods:

Between March and October 2007, an epidemic of DLK was detected in one center. During this period, 6 surgeons performed 1161 LASIK or flap lift procedures. From March to August 2007, data were retrospectively collected corresponding to pre- and postoperative clinical findings and environmental risk factors related to the operating room, auxiliary staff, sterilization, and surgical equipment (phase 1). Incidence and distribution of cases are described. From August to October 2007, a prospective epidemiological study was completed, analyzing the clinical and intraoperative variables associated with the outbreak (phase 2). A plan of action was applied covering a wide range of possible causes.

Results:

During phase 1, 25.79% of eyes developed DLK. A greater incidence was found in eyes operated on Mondays and a smaller incidence was found when povidone-iodine was used for disinfection of the instruments. Actions taken by the staff to stop the outbreak had no effect, and epidemiologists designed a strategy aimed at addressing all possible weak points and the prospective study for detecting causes. The incidence decreased to 1.87% and a weak significant association was found for sex, atopy, drug allergies, spherical equivalent refraction, and mechanical microkeratome.

Conclusions:

Strategies aimed at addressing all possible etiological factors can stop an epidemic of DLK even when a single cause has not been isolated.
Refractive Outcomes and Quality of Vision Related to an Outbreak of Diffuse Lamellar Keratitis
Authors: Javaloy Jaime , Alió Jorge L. , El Kady Bassam , Muñoz Gonzalo , Barraquer Rafael I. , Maldonado Miguel J.
Published: May 2011

Purpose:

To report the impact on visual function and corneal aberrations during an epidemic of diffuse lamellar keratitis (DLK).

Methods:

A retrospective, comparative, and consecutive case-control study was performed, involving 418 eyes operated between March and October 2007 in the refractive surgery unit of one center. Eyes were separated into groups: group 1 (DLK group) included 209 eyes that presented with DLK after LASIK and group 2 (control group) included 209 unaffected, consecutive eyes operated from the beginning of the outbreak. Refractive variables and corneal aberrations were compared between the two groups.

Results:

Visual outcomes were significantly different when comparing control eyes and eyes with DLK grades 3 and 4, but not for eyes with DLK grades 1 and 2. Uncorrected distance visual acuity (UDVA) significantly improved from the third month after DLK was diagnosed (Kruskal-Wallis,
P
=.02). Corrected distance visual acuity (CDVA) did not decrease significantly with DLK grades 1 and 2 (preoperative CDVA vs 1, 3, and 6 months after diagnosis; Mann-Whitney,
P
>.05, respectively). At the end of follow-up, UDVA and CDVA were not significantly different between the two groups. Eyes suffering from DLK had significantly increased corneal aberrations, except for spherical and astigmatism aberrations, 3 months after being diagnosed (Kruskal-Wallis,
P
<.05); however, corneal aberrations were not significantly different between the DLK and control groups (Mann-Whitney,
P
>.05).

Conclusions:

The outbreak of DLK did not induce a significant decrease in global visual outcomes, except in severe cases, and postoperative corneal aberrations were not affected.
Effects of LASIK on Corneal Endothelium Using the 15-kHz IntraLase Femtosecond Laser
Authors: Muñoz Gonzalo , Albarrán-Diego César , Sakla Hani F. , Ferrer-Blasco Teresa , Javaloy Jaime
Published: May 2011

PURPOSE:

To assess the effects of LASIK with the 15-kHz IntraLase femtosecond laser on corneal endothelium.

METHODS:

In a prospective, single-center clinical trial, 138 patients (mean age: 32.0±7.1 years [range: 21 to 42 years]) underwent femtosecond LASIK for the correction of myopia −0.75 to −9.00 diopters (D) and cylinder up to 3.25 D. Patients were divided into two groups: contact lens group (n=76) and non-contact lens group (n=62). Pre- and 12-month postoperative specular microscopy of the central corneal endothelium was performed. The integrity of the central endothelium was assessed in terms of endothelial cell density and percentage of hexagonality.

RESULTS:

In the contact lens group, mean endothelial cell density improved significantly from 3401±292 cells/mm
2
to 3587±262 cells/mm
2
(
P
<.001) with a mean increase of 5.5%. The percentage of hexagonal cells was statistically significantly higher after surgery (32.5±4.0%) compared with preoperative data (31.0±5.1%) (
P
=.035). No statistically significant differences were noted regarding mean endothelial cell density (
P
=.126) or hexagonality (
P
=.56) before and 1 year after femtosecond LASIK in the non-contact lens group.

CONCLUSIONS:

Femtosecond LASIK to correct myopia was safe for the corneal endothelium. Improvement in mean endothelial cell density and percentage of hexagonality was observed in the contact lens group.
Incidence and Characteristics of Unilateral Keratoconus Classified on Corneal Topography
Authors: Wei Rui Hua , Zhao Shao Zhen , Lim Li , Tan Donald T.H.
Published: May 2011

PURPOSE:

To evaluate the characteristics of unilateral keratoconus defined on the basis of corneal topography and analyze videokeratography parameters between fellow eyes and normal controls.

METHODS:

A total of 111 patients with clinical keratoconus were prospectively enrolled. Both eyes were evaluated with Tomey (Tomey Corp) and Orbscan II (Bausch & Lomb) corneal topography systems. The patient was classified as having unilateral keratoconus if one eye had clinical keratoconus and the other eye did not have any topographic signs of keratoconus such as asymmetric videokeratographic pattern, positive result in Tomey keratoconus screening, maximum posterior elevation >40 μm, or corneal thinnest pachymetry <500 μm. Clinical characteristics and 13 Orbscan II quantitative indices between keratoconic and fellow eyes and normal control eyes were evaluated.

RESULTS:

Five (4.5%) of 111 patients with keratoconus had no topographic evidence of keratoconus in the fellow eye. All clinically normal fellow eyes had symmetric bowtie patterns. Statistically significant differences were noted in maximum posterior elevation, corneal irregularity, and corneal thinnest values between keratoconic eyes and fellow eyes, and between keratoconic eyes and control eyes. Only 3-mm irregularity was significantly higher in the fellow eyes compared with control eyes (
P
<.05). An increased trend for corneal 5-mm irregularity was found in fellow eyes compared to control eyes.

CONCLUSIONS:

The incidence of unilateral keratoconus was 4.5%. A trend of higher irregularity was found in fellow eyes compared with control eyes. This finding indicates that fellow eyes may show a certain low-expressivity morphologic feature of keratoconus.
A Narrow Silicone Sponge to Close a Wider Retinal Tear: The Open-Book Technique of Scleral Buckling
Authors: Chang Yun-Hsiang , Pao Shu-I , Chen Ying-Jen , Chen Jiann-Torng
Published: May 2011

The authors describe a modified technique for scleral buckling by which a wide retinal tear can be closed with a relatively narrow buckle. An incomplete cut on the silicone sponge can be made so that the halves are connected to each other by a narrow strip of material and opened like a book when buckling. Using this open-book technique, silicone sponges can be used to close horseshoe-shaped retinal tears of one to two times the width of available silicone sponges. This technique was used in four eyes with excellent anatomical results, and no complications could be attributed to the surgical technique. This technique provides an alternative treatment strategy for retinal detachment with relatively wide retinal tears.
Anterior Chamber Depth Measurements Obtained with Pentacam HR
®
Imaging System and Conventional A-Scan Ultrasound
Authors: Szalai Eszter , Berta András , Németh Gábor , Hassan Ziad , Módis László
Published: May 2011

Background and Objective:

To evaluate the reliability and repeatability of anterior chamber depth (ACD) measurements obtained with the rotating Scheimpflug camera and conventional A-scan ultrasound.

Patients and Methods:

The right eyes of 46 healthy volunteers were examined. ACD was determined first with the Pentacam HR (Oculus, Wetzlar, Germany) and then by ultrasound (AL-2000; Tomey, Tennenlohe, Germany).

Results:

The mean ACD results were significantly shallower when obtained with the Pentacam HR (Investigator 1: 2.89 ± 0.41 mm; Investigator 2: 2.90 ± 0.41 mm) than with ultrasound (Investigator 1: 3.08 ± 0.43 mm,
P
< .0001; Investigator 2: 3.00 ± 0.45,
P
= .0005). Significant and strong correlation was observed between the two techniques (Investigator 1: r = 0.937; Investigator 2: r = 0.913).

Conclusion:

ACD measurements obtained with the Pentacam HR seemed to be reliable and repeatable when the cornea was optically clear. The significant differences between the Pentacam HR and ultrasound indicate that the two devices should not be used interchangeably for ACD measurements.
Repeatability of Optic Nerve Head Parameters Measured by Spectral-Domain OCT in Healthy Eyes
Authors: Savini Giacomo , Carbonelli Michele , Parisi Vincenzo , Barboni Piero
Published: May 2011

Background and Objective:

To evaluate the repeatability of optic nerve head (ONH) measurements by spectral-domain optical coherence tomography.

Patients and Methods:

Three scans were acquired in 32 healthy subjects during one session. Using Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA), the cup-to-disc ratio (CDR), disc area, rim area, cup volume, and horizontal and vertical CDRs were investigated. Repeatability was assessed by the coefficient of variation (COV), the test–retest intrasession variability, and the intraclass correlation coefficient (ICC).

Results:

Good repeatability was achieved for all parameters, with a COV of 4.23% or less and ICCs of 0.98 or greater for all measurements. Test–retest intrasession variability was 0.024 for CDR, 0.121 mm
2
for disc area, 0.087 mm
2
for rim area, 0.017 mm
3
for cup volume, and 0.048 for horizontal and vertical CDR.

Conclusion:

In healthy eyes, Cirrus HD-OCT provides repeatable measurements of ONH parameters.
An Augmented Trabeculectomy for Neovascular Glaucoma
Authors: Dahan Elie , Ben Simon Guy J.
Published: May 2011

Background and Objective:

To report on a new surgical technique for neovascular glaucoma (NVG) in patients with proliferative diabetic retinopathy or retinal vein occlusion.

Patients and Methods:

Fourteen eyes of 13 patients underwent an augmented trabeculectomy for NVG between January 2000 and February 2003. The augmented trabeculectomy consisted of a 7 × 5 × 5 mm trapezoidal scleral flap, a 6 × 4 × 4 mm deep sclerectomy, application of mitomycin C (MMC) 0.2% for 3 minutes in the deep scleral bed, a 2 × 1 mm trabeculectomy, and the use of a hydrophilic implant (T-flux; Carl Zeiss Meditec, Wetzlar, Germany) as a wick drain connecting the posterior chamber and the deep sclerectomy via a peripheral iridectomy. Whenever the intraocular pressure (IOP) rose above 20 mm Hg, the site of filtration was surgically revised and MMC 0.2% was reapplied in the deep scleral bed.

Results:

IOP decreased from a mean of 38.7 ± 5.2 mm Hg preoperatively to a mean of 17.3 ± 5.2 mm Hg postoperatively after a mean follow-up of 32 ± 12 months (
P
= .001, Wilcoxon signed-ranked test, two related samples). Mean visual acuity improved from 20/350 to 20/170 (
P
= .034). Seven eyes (50%) needed one surgical revision and one eye (7%) needed two surgical revisions within 3 months from the first operation to maintain an IOP of less than 21 mm Hg.

Conclusion:

The modified trabeculectomy augmented by MMC 0.2% and the use of the T-flux as a wick drain can provide adequate IOP control in NVG caused by proliferative diabetic retinopathy or retinal vein occlusion. To maintain an IOP of less than 21 mm Hg without anti-glaucoma medications, surgical revisions of the filtration site are necessary in at least 50% of patients.
Factors Contributing to Posterior Capsule Opacification Following 23-Gauge Transconjunctival Phacovitrectomy
Authors: Rahman Rubina , Briffa Benedict Vella , Gupta Abha , Chinn David J.
Published: May 2011

Background and Objective:

To determine posterior capsule opacification (PCO) rate and identify contributory factors in a series of patients undergoing combined 23-gauge transconjunctival phacovitrectomy.

Patients and Methods:

Retrospective data on 221 consecutive patients operated on by a single senior surgeon using a standard technique were collected and subjected to univariate analysis with chi-square tests and multivariate analysis with logistic regression.

Results:

PCO developed in 46 of 221 cases (20.8%). Major risk factors were: rhegmatogenous retinal detachment (relative risk = 3.3,
P
= .002), axial length greater than 24.5 mm (relative risk = 2.0,
P
= .093), intraoperative/postoperative complications (relative risk = 3.3,
P
= .04), C
2
F
6
tamponade (versus SF
6
/air) (relative risk = 2.8,
P
= .01), and postoperative posturing (relative risk = 4.1,
P
< .001). Multiple logistic regression analysis showed the latter two to be most important.

Conclusion:

PCO rate following 23-gauge phacovitrectomy is lower than most rates reported for 20-gauge phacovitrectomy. Using shorter-acting gas tamponade and avoiding postoperative posturing may help lower PCO rates.
Docking of Lytic Granules at the Immunological Synapse in Human CTL Requires Vti1b-Dependent Pairing with CD3 Endosomes
Authors: Qu Bin , Pattu Varsha , Junker Christian , Schwarz Eva C. , Bhat Shruthi S. , Kummerow Carsten , Marshall Misty , Matti Ulf , Neumann Frank , Pfreundschuh Michael , Becherer Ute , Rieger Heiko , Rettig Jens , Hoth Markus
Published: May 2011

Lytic granule (LG)-mediated apoptosis is the main mechanism by which CTL kill virus-infected and tumorigenic target cells. CTL form a tight junction with the target cells, which is called the immunological synapse (IS). To avoid unwanted killing of neighboring cells, exocytosis of lytic granules (LG) is tightly controlled and restricted to the IS. In this study, we show that in activated human primary CD8+ T cells, docking of LG at the IS requires tethering LG with CD3-containing endosomes (CD3-endo). Combining total internal reflection fluorescence microscopy and fast deconvolution microscopy (both in living cells) with confocal microscopy (in fixed cells), we found that LG and CD3-endo tether and are cotransported to the IS. Paired but not single LG are accumulated at the IS. The dwell time of LG at the IS is substantially enhanced by tethering with CD3-endo, resulting in a preferential release of paired LG over single LG. The SNARE protein Vti1b is required for tethering of LG and CD3-endo. Downregulation of Vti1b reduces tethering of LG with CD3-endo. This leads to an impaired accumulation and docking of LG at the IS and a reduction of target cell killing. Therefore, Vti1b-dependent tethering of LG and CD3-endo determines accumulation, docking, and efficient lytic granule secretion at the IS.
Rapid Assessment of Age-Related Differences in Standing Balance
Authors: Kalisch Tobias , Kattenstroth Jan-Christoph , Noth Sebastian , Tegenthoff Martin , Dinse Hubert R.
Published: May 2011

As life expectancy continues to rise, in the future there will be an increasing number of older people prone to falling. Accordingly, there is an urgent need for comprehensive testing of older individuals to collect data and to identify possible risk factors for falling. Here we use a low-cost force platform to rapidly assess deficits in balance under various conditions. We tested 21 healthy older adults and 24 young adults during static stance, unidirectional and rotational displacement of their centre of pressure (COP). We found an age-related increase in postural sway during quiet standing and a reduction of maximal COP displacement in unidirectional and rotational displacement tests. Our data show that even low-cost computerized assessment tools allow for the comprehensive testing of balance performance in older subjects.
New Developments in Electrochemical Sensors Based on Poly(3,4-ethylenedioxythiophene)-Modified Electrodes
Authors: Lupu Stelian
Published: May 2011

There is a growing demand for continuous, fast, selective, and sensitive monitoring of key analytes and parameters in the control of diseases and health monitoring, foods quality and safety, and quality of the environment. Sensors based on electrochemical transducers represent very promising tools in this context. Conducting polymers (CPs) have drawn considerable interest in recent years because of their potential applications in different fields such as in sensors, electrochemical displays, and in catalysis. Among the organic conducting polymers, poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives have attracted particular interest due to their high stability and high conductivity. This paper summarizes mainly the recent developments in the use of PEDOT-based composite materials in electrochemical sensors.
Electroencephalographic Rhythms in Alzheimer′s Disease
Authors: Lizio Roberta , Vecchio Fabrizio , Frisoni Giovanni B. , Ferri Raffaele , Rodriguez Guido , Babiloni Claudio
Published: May 2011

Physiological brain aging is characterized by synapses loss and neurodegeneration that slowly lead to an age‐related decline of cognition. Neural/synaptic redundancy and plastic remodelling of brain networking, also due to mental and physical training, promotes maintenance of brain activity in healthy elderly subjects for everyday life and good social behaviour and intellectual capabilities. However, age is the major risk factor for most common neurodegenerative disorders that impact on cognition, like Alzheimer′s disease (AD). Brain electromagnetic activity is a feature of neuronal network function in various brain regions. Modern neurophysiological techniques, such as electroencephalography (EEG) and event‐related potentials (ERPs), are useful tools in the investigation of brain cognitive function in normal and pathological aging with an excellent time resolution. These techniques can index normal and abnormal brain aging analysis of corticocortical connectivity and neuronal synchronization of rhythmic oscillations at various frequencies. The present review suggests that discrimination between physiological and pathological brain aging clearly emerges at the group level, with suggested applications also at the level of single individual. The possibility of combining the use of EEG together with biological/neuropsychological markers and structural/functional imaging is promising for a low‐cost, non‐invasive, and widely available assessment of groups of individuals at‐risk.
Scanning Electrochemical Microscopy as a Tool for the Characterization of Dental Erosion
Authors: Castro Pollyana S. , Lima Alex S. , Ferreira Tiago L. , Bertotti Mauro
Published: May 2011

When the tooth is exposed to acidic environments, an irreversible loss of dental hard tissue occurs in a process called dental erosion. In this work, the scanning electrochemical microscopy (SECM) was used to probe the consumption of protons at the vicinity of a tooth surface with a platinum microelectrode fixed at −0.5 (V) versus Ag/AgCl/KCl(sat). SECM approach curves were recorded to assess the extent of diffusion in the solution close to the tooth substrate. SECM images clearly demonstrated that the acid erosion process is very fast at solution pH values in the range between 3 and 4.
Fulminating Septic Shock from Clostridium Perfringens in an Early Breast Cancer Patient with Severe Myalgia after Docetaxel Treatment
Authors: Minisini Alessandro Marco , Menis Jessica , Follador Alessandro , Avellini Claudio , Fasola Gianpiero
Published: May 2011

Anaerobic bacteraemia could be a lifethreatening condition in neutropenic patients receiving chemotherapy. Taxane therapy is associated with necrotising inflammation of the caecum (named also typhlitis) that could be a potential source for bacteraemia. We report the case of a sudden onset of septic shock by Clostridium perfringens in a young patient treated with docetaxel as adjuvant chemotherapy for early breast cancer. A minireview of the literature has been performed.
Philosophical counselling: Towards a ‘new approach’ in pastoral care and counselling?
Authors: Louw Daniel J.
Published: May 2011

The practice of pastoral counselling was dominated for several decades by the Rogerian techniques of empathetic listening. To a large extent, healing was predominately related to the realm of feelings (the affective dimension). Rational Emotive Therapy opened up other avenues. However, besides Logotherapy, the realm of meaning and its connectedness to world views and ideas (Plato: forms) remained uncharted in many theories for pastoral care and counselling. In this article it was argued that philosophical counselling opens up new avenues for pastoral care and counselling. Philosophical counselling probes into the realm of different schemata of interpretation. A model for the making of a spiritual existential analysis was proposed in order to detect the impact of the Christian spiritual schema of interpretation on the dynamics of existential networking.
Evaluation of the carbon content of aerosols from the burning of biomass in the Brazilian Amazon using thermal, optical and thermal-optical analysis methods
Authors: Soto-García L. L. , Andreae M. O. , Andreae T. W. , Artaxo P. , Maenhaut W. , Kirchstetter T. , Novakov T. , Chow J. C. , Mayol-Bracero O. L.
Published: May 2011

Abstract. Aerosol samples were collected at a pasture site in the Amazon Basin as part of the project LBA-SMOCC-2002 (Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke Aerosols, Clouds, Rainfall and Climate: Aerosols from Biomass Burning Perturb Global and Regional Climate). Sampling was conducted during the late dry season, when the aerosol composition was dominated by biomass burning emissions, especially in the submicron fraction. A 13-stage Dekati low-pressure impactor (DLPI) was used to collect particles with nominal aerodynamic diameters (Dp) ranging from 0.03 to 0.10 μm. Gravimetric analyses of the DLPI substrates and filters were performed to obtain aerosol mass concentrations. The concentrations of total, apparent elemental, and organic carbon (TC, ECa, and OC) were determined using thermal and thermal-optical analysis (TOA) methods. A light transmission method (LTM) was used to determine the concentration of equivalent black carbon (BCe) or the absorbing fraction at 880 nm for the size-resolved samples. During the dry period, due to the pervasive presence of fires in the region upwind of the sampling site, concentrations of fine aerosols (Dp<2.5 μm: average 59.8 μg m−3) were higher than coarse aerosols (Dp> 2.5 μm: 4.1 μg m−3). Carbonaceous matter, estimated as the sum of the particulate organic matter (i.e., OC × 1.8) plus BCe, comprised more than 90% to the total aerosol mass. Concentrations of ECa (estimated by thermal analysis with a correction for charring) and BCe (estimated by LTM) averaged 5.2 ± 1.3 and 3.1 ± 0.8 μg m−3, respectively. The determination of EC was improved by extracting water-soluble organic material from the samples, which reduced the average light absorption Ångström exponent of particles in the size range of 0.1 to 1.0 μm from >2.0 to approximately 1.2. The size-resolved BCe measured by the LTM showed a clear maximum between 0.4 and 0.6 μm in diameter. The concentrations of OC and BCe varied diurnally during the dry period, and this variation is related to diurnal changes in boundary layer thickness and in fire frequency.
Estimate of bias in Aura TES HDO/H2O profiles from comparison of TES and in situ HDO/H2O measurements at the Mauna Loa observatory
Authors: Worden J. , Noone D. , Galewsky J. , Bailey A. , Bowman K. , Brown D. , Hurley J. , Kulawik S. , Lee J. , Strong M.
Published: May 2011

Abstract. The Aura satellite Tropospheric Emission Spectrometer (TES) instrument is capable of measuring the HDO/H2O ratio in the lower troposphere using thermal infrared radiances between 1200 and 1350 cm−1. However, direct validation of these measurements is challenging due to a lack of in situ measured vertical profiles of the HDO/H2O ratio that are spatially and temporally co-located with the TES observations. From 11 October through 5 November 2008, we undertook a campaign to measure HDO and H2O at the Mauna Loa observatory in Hawaii for comparison with TES observations. The Mauna Loa observatory is situated at 3.1 km above sea level or approximately 680 hPa, which is approximately the altitude where the TES HDO/H2O observations show the most sensitivity. Another advantage of comparing in situ data from this site to estimates derived from thermal IR radiances is that the volcanic rock is heated by sunlight during the day, thus providing significant thermal contrast between the surface and atmosphere; this thermal contrast increases the sensitivity to near surface estimates of tropospheric trace gases. The objective of this inter-comparison is to better characterize a bias in the TES HDO data, which had been previously estimated to be approximately 5 % too high for a column integrated value between 850 hPa and 500 hPa. We estimate that the TES HDO profiles should be corrected downwards by approximately 4.8 % and 6.3 % for Versions 3 and 4 of the data respectively. These corrections must account for the vertical sensitivity of the TES HDO estimates. We estimate that the precision of this bias correction is approximately 1.9 %. The accuracy is driven by the corrections applied to the in situ HDO and H2O measurements using flask data taken during the inter-comparison campaign and is estimated to be less than 1 %. Future comparisons of TES data to accurate vertical profiles of in situ measurements are needed to refine this bias estimate.
Detailed heterogeneous oxidation of soot surfaces in a particle-resolved aerosol model
Authors: Kaiser J. C. , Riemer N. , Knopf D. A.
Published: May 2011

Abstract. Using the particle-resolved aerosol model PartMC-MOSAIC, we simulate the heterogeneous oxidation of a monolayer of polycyclic aromatic hydrocarbons (PAHs) on soot particles in an urban atmosphere. We focus on the interaction of the major atmospheric oxidants (O3, NO2, OH, and NO3) with PAHs and include competitive co-adsorption of water vapour for a range of atmospheric conditions. For the first time detailed heterogeneous chemistry based on the Pöschl-Rudich-Ammann (PRA) framework is modelled on soot particles with a realistic size distribution and a continuous range of chemical ages. We find PAHs half-lives, τ1/2, on the order of seconds during the night, when the PAHs are rapidly oxidised by the gas-surface reaction with NO3. During the day, τ1/2 is on the order of minutes and determined mostly by the surface layer reaction of PAHs with adsorbed O3. Such short half-lives of surface-bound PAHs may lead to efficient conversion of hydrophobic soot into more hygroscopic particles, thus increasing the particles' aerosol-cloud interaction potential. Despite its high reactivity OH appears to have a negligible effect on PAH degradation which can be explained by its very low concentration in the atmosphere. An increase of relative humidity (RH) from 30 % to 80 % increases PAH half-lives by up to 50 % for daytime degradation and by up to 100 % or more for nighttime degradation. Uptake coefficients, averaged over the particle population, are found to be relatively constant over time for O3 (∼2 × 10−7 to ∼2 × 10−6) and NO2 (∼5 × 10−6 to ∼10−5) at the different levels of NOx emissions and RH considered in this study. In contrast, those for OH and NO3 depend strongly on the surface concentration of PAHs. We do not find a significant influence of heterogeneous reactions on soot particles on the gas phase composition. The derived half-lives of surface-bound PAHs and the time and particle population averaged uptake coefficients for O3 and NO2 presented in this paper can be used as parameterisations for the treatment of heterogeneous chemistry in large-scale atmospheric chemistry models.
Large scale modeling of the transport, chemical transformation and mass budget of the sulfur emitted during the April 2007 eruption of Piton de la Fournaise
Authors: Tulet P. , Villeneuve N.
Published: May 2011

Abstract. In April 2007, the Piton de la Fournaise volcano (Réunion island) entered into its biggest eruption recorded in the last century. Due to the absence of a sensors network in the vicinity of the volcano, an estimation of degassing during the paroxysmal phase of the event has not been performed. Nevertheless, the SO2 plume and aerosols have been observed by the OMI and CALIOP space sensors, respectively. The mesoscale chemical model MesoNH-C simulates the observed bulk mass of SO2 and the general shape of the SO2 plume spreading over the Indian Ocean. Moreover, an analysis of the SO2 plume budget estimates a total SO2 release of 230 kt, among of which 60 kt have been transformed into H2SO4. 27 kt of SO2 and 21 kt of H2SO4 have been deposited at the surface by dry deposition. With this top down approach, the temporal evolution of the SO2 emission has been estimated during the most active period of the eruption. The peak of degassing was estimated at 1800 kg s−1 in the morning of 6~April. The temporal evolution of SO2 emission presented here can also be used for local studies.
Calibration of TCCON column-averaged CO2: the first aircraft campaign over European TCCON sites
Authors: Messerschmidt J. , Geibel M. C. , Blumenstock T. , Chen H. , Deutscher N. M. , Engel A. , Feist D. G. , Gerbig C. , Gisi M. , Hase F. , Katrynski K. , Kolle O. , Lavrič J. V. , Notholt J. , Palm M. , Ramonet M. , Rettinger M. , Schmidt M. , Sussmann R. , Toon G. C. , Truong F. , Warneke T. , Wennberg P. O. , Wunch D. , Xueref-Remy I.
Published: May 2011

Abstract. The Total Carbon Column Observing Network (TCCON) is a ground-based network of Fourier Transform Spectrometer (FTS) sites around the globe, where the column abundances of CO2, CH4, N2O, CO and O2 are measured. CO2 is constrained with a precision better than 0.25 %. To achieve a similarly high accuracy, calibration to World Meteorological Organization (WMO) standards is required. This paper introduces the first aircraft calibration campaign of five European TCCON sites and a mobile FTS instrument. A series of WMO standards in-situ profiles were obtained over European TCCON sites via aircraft and compared with retrievals of CO2 column amounts from the TCCON instruments. The results of the campaign show that the FTS measurements are consistently biased 1.0 % ± 0.2 % low with respect to WMO standards, in agreement with previous TCCON calibration campaigns. The standard a priori profile for the TCCON FTS retrievals is shown to not add a bias. The same calibration factor is generated using aircraft profiles as a priori and with the TCCON standard a priori. With a calibration to WMO standards, the highly precise TCCON CO2 measurements of total column concentrations provide a suitable database for the calibration and validation of nadir-viewing satellites.
Seasonal variation in vertical volatile compounds air concentrations within a remote hemiboreal mixed forest
Authors: Noe S. M. , Hüve K. , Niinemets Ü. , Copolovici L.
Published: May 2011

Abstract. The vertical distribution of ambient biogenic volatile organic compounds (BVOC) concentrations within a hemiboreal forest canopy was investigated over a period of one year. Variability in temporal and spatial isoprene concentrations can be mainly explained by biogenic emissions from deciduous trees, ranging from 0.1 to 7.5 μg m−3. Monoterpene concentrations exceeded isoprene largely and ranged from 0.01 to 140 μg m−3 and during winter time anthropogenic contributions are likely. Variation in monoterpene concentrations found to be largest right above the ground and the vertical profile suggest a weak mixing leading to terpene accumulation in the lower canopy. Exceptionally high values were recorded during a heat wave in July 2010 with very high midday temperatures above 30 °C for several weeks. During summer months, monoterpene exceeded isoprene concentrations 6-fold and during winter 12-fold. The relative contribution of diverse monoterpene species to the ambient concentrations revealed a dominance of α-pinene in the lower and of limonene in the upper part of the canopy, both accounting for up to 70 % of the total monoterpene concentration during summer months. The main contributing monoterpene during wintertime was Δ3-carene accounting for 60 % of total monoterpene concentration in January. Possible biogenic monoterpene sources beside the foliage are the leaf litter, the soil and also resins exuding from stems. In comparison, the hemiboreal mixed forest canopy showed similar isoprene but higher monoterpene concentrations than the boreal forest and lower isoprene but substantially higher monoterpene concentrations than the temperate mixed forest canopies. These results have major implications for simulating air chemistry and secondary organic aerosol formation within and above hemiboreal forest canopies.
Simulation of particle formation and number concentration over the Eastern United States with the WRF-Chem + APM model
Authors: Luo G. , Yu F.
Published: May 2011

Abstract. Aerosol nucleation events, widely observed at various locations around the globe, are a significant source of cloud condensation nuclei (CCN) which determines aerosol indirect radiative forcing. In this study, a size-resolved, computationally efficient, advanced particle microphysics (APM) model, which has been previously incorporated into a global chemistry transport model (GEOS-Chem), is integrated into the Weather Research and Forecast model coupled with Chemistry (WRF-Chem) to study new particle formation and its contribution to particle number concentration and CCN abundances over the Eastern United States. Size- and composition-resolved aerosol properties from GEOS-Chem + APM simulations are used to initialize the WRF-Chem + APM model, reducing the WRF-Chem spin-up time substantially. The modeling results have been evaluated with the relevant measurements obtained during the INTEX-A field campaign in the summer of 2004 and reasonable agreements have been obtained. The particle formation and number concentrations simulated by WRF-Chem + APM are generally consistent with those based on GEOS-Chem + APM over the Eastern United States, but the WRF-Chem + APM simulation has a much higher spatial resolution and can reveal urban and even plume scale processes. Our simulations show that high values of nucleation rates are largely confined to the regions of high SO2 emissions and that aerosol nucleation dominates the spatial and temporal distributions of condensation nuclei lager than 10 nm (CN10). Similarly, high concentrations of CCN at supersaturation of 0.4 % (CCN0.4) are generally confined to SO2 source regions, with the highest monthly (July) mean CCN0.4 value exceeding 1600 # cm−3 in the lower troposphere over Indiana and Ohio. Nucleation and subsequent growth of secondary particles are important sources of CCN0.4, accounting for more than 80 % in most parts of the Eastern United States.
Results from the first national UK inter-laboratory calibration for very short-lived halocarbons
Authors: Jones C. E. , Andrews S. J. , Carpenter L. J. , Hogan C. , Hopkins F. E. , Laube J. C. , Robinson A. D. , Spain T. G. , Archer S. D. , Harris N. R. P. , Nightingale P. D. , O'Doherty S. J. , Oram D. E. , Pyle J. A. , Butler J. H. , Hall B. D.
Published: May 2011

Abstract. Very short-lived halocarbons (VSLH) such as CH3I, CH2Br2 and CHBr3 provide an important source of reactive halogens to the atmosphere, however high spatial and seasonal variability in their ambient mixing ratios and sea-air fluxes gives rise to considerable uncertainty in global scale emission estimates. One solution to improve global flux estimates is to combine the multitude of individually published datasets to produce a database of collated global halocarbon observations. Some progress towards this has already been achieved through the HalOcAt (Halocarbons in the Ocean and Atmosphere) database initiative, but the absence of a common calibration scale for very short-lived halocarbons makes it difficult to distinguish true environmental variations from artefacts arising from differences between calibration methodologies. As such, the lack of inter-calibrations for both air and seawater measurements of very short-lived halocarbons has been identified as a major limitation to current estimations of the global scale impact of these reactive trace gases. Here we present the key findings from the first national UK inter-laboratory comparison for calibrations of the halocarbons CH3I, CH2Br2 and CHBr3. The aim of this inter-calibration was to provide transparency between halocarbon calibrations from major UK research institutions, an important step towards enabling all measurements from these institutions to be treated as one coherent integrated dataset for global source term parameterisations.
Estimation of isoprenoid emission factors from enclosure studies: measurements, data processing, quality and standardized measurement protocols
Authors: Niinemets Ü. , Kuhn U. , Harley P. C. , Staudt M. , Arneth A. , Cescatti A. , Ciccioli P. , Copolovici L. , Geron C. , Guenther A. , Kesselmeier J. , Lerdau M. T. , Monson R. K. , Peñuelas J.
Published: May 2011

Abstract. The capacity for volatile isoprenoid production under standardized environmental conditions (ES), the emission factor) is a key characteristic in constructing isoprenoid emission inventories. However, there is large variation in published ES estimates for any given species, and this variation leads to significant uncertainties in emission predictions. We review the sources of variation in ES that are due to measurement and analytical techniques and calculation and averaging procedures. This review demonstrates that estimations of ES critically depend on applied experimental protocols and on data processing and reporting. A great variety of experimental setups has been used in the past, contributing to study-to-study variations in ES estimates. We suggest that past experimental data should be distributed into broad quality classes depending on whether the data can or cannot be considered quantitative based on rigorous experimental standards. Apart from analytical issues, the accuracy of ES values is strongly driven by extrapolation and integration errors introduced during data processing. Additional sources of error, especially in meta-database construction, can further arise from inconsistent use of units and expression bases of ES. We propose a standardized experimental protocol for BVOC estimations and highlight basic meta-information that we strongly recommend to report with any ES measurement. We conclude that standardization of experimental and calculation protocols and critical examination of past reports is essential for development of accurate emission factor databases.
Estimating the permafrost-carbon feedback on global warming
Authors: Schneider von Deimling T. , Meinshausen M. , Levermann A. , Huber V. , Frieler K. , Lawrence D. M. , Brovkin V.
Published: May 2011

Abstract. Thawing of permafrost and the associated release of carbon constitutes a positive feedback in the climate system, elevating the effect of anthropogenic GHG emissions on global-mean temperatures. Multiple factors have hindered the quantification of this feedback, which was not included in the CMIP3 and C4MIP generation of AOGCMs and carbon cycle models. There are considerable uncertainties in the rate and extent of permafrost thaw, the hydrological and vegetation response to permafrost thaw, the decomposition timescales of freshly thawed organic material, the proportion of soil carbon that might be emitted as carbon dioxide via aerobic decomposition or as methane via anaerobic decomposition, and in the magnitude of the high latitude amplification of global warming that will drive permafrost degradation. Additionally, there are extensive and poorly characterized regional heterogeneities in soil properties, carbon content, and hydrology. Here, we couple a new permafrost module to a reduced complexity carbon-cycle climate model, which allows us to perform a large ensemble of simulations. The ensemble is designed to span the uncertainties listed above and thereby the results provide an estimate of the potential strength of the permafrost-carbon feedback. For the high CO2 concentration scenario (RCP8.5), 12–52 PgC, or an extra 3–11 % above projected net CO2 emissions from land carbon cycle feedbacks, are released by 2100 (68 % uncertainty range). This leads to an additional warming of 0.02–0.11 °C. Though projected 21st century emissions are relatively modest, ongoing permafrost thaw and slow but steady soil carbon decomposition means that, by 2300, more than half of the potentially vulnerable permafrost carbon stock in the upper 3m of soil layer (600–1000 PgC) could be released as CO2, with an extra 1–3 % being released as methane. Our results also suggest that mitigation action in line with the lower scenario RCP3-PD could contain Arctic temperature increase sufficiently that thawing of the permafrost area is limited to 15–30 % and the permafrost-carbon induced temperature increase does not exceed 0.01–0.07 °C by 2300.
Diffuse hydrological mass transport through catchments: scenario analysis of physical and biogeochemical uncertainty effects
Authors: Persson K. , Jarsjö J. , Destouni G.
Published: May 2011

Abstract. This paper develops and investigates the applicability of a scenario analysis approach to quantify and map the effects of physical and biogeochemical variability, cross-correlation and uncertainty on expected hydrological mass loading from diffuse sources. The approach enables identification of conservative assumptions, uncertainty ranges, as well as pollutant/nutrient release locations and situations for which further investigations are most needed in order to reduce the most important uncertainty effects. The present scenario results provide different statistical and geographic distributions of advective travel times for diffuse hydrological mass transport, and show that neglect or underestimation of the physical advection variability implies substantial risk to underestimate pollutant and nutrient loads to downstream surface and coastal waters. This is particularly true for relatively high catchment-characteristic product between average attenuation rate and average advective travel time, for which mass delivery would be near zero under assumed transport homogeneity but can be orders of magnitude higher for variable transport conditions. A scenario of high advection variability, combined with a relevant average biogeochemical mass attenuation rate, emerges consistently from the example catchment results as a generally reasonable, conservative assumption for estimating maximum diffuse mass loading when the prevailing physical and biogeochemical variability and cross-correlation are uncertain. The geographic mapping of advective travel times for this high-variability scenario identifies also directly the potential hotspot areas with large mass loading to downstream surface and coastal waters, as well as their opposite, the potential lowest-impact areas within the catchment.