bluuebunny/crossref_metadata_2025 huggingface dataset:
Global Partnering Opportunities and Challenges of Psoriasis and Psoriatic Arthritis in Latin America: A Report from the GRAPPA 2010 Annual Meeting
Authors: ESPINOZA LUIS R. , TOLOZA SERGIO M.A. , VALLE-ONATE RAFAEL , MEASE PHILIP J.
Published: February 2012

Documenting the disease burden of psoriasis and psoriatic arthritis (PsA) in Central and South America is difficult. The most conclusive data have come from the Iberoamerican Registry of Spondyloarthritis (RESPONDIA), which registered patients with a diagnosis of spondyloarthritis in a multinational, multicenter (Argentina, Brazil, Costa Rica, Chile, Mexico, Peru, Uruguay, Venezuela, Spain, and Portugal) cross-sectional study conducted between 2006 and 2007. Compared with elsewhere in the Western world, patients with PsA from RESPONDIA were older at study visit, at onset of symptoms, and at diagnosis of spondyloarthritis (SpA); had longer mean disease duration from onset of symptoms to diagnosis; and were more likely to have dactylitis, nail involvement, enthesitis, and peripheral arthritis in lower and upper extremities. It is critical to understand the biologic basis, estimate the disease burden, and determine the clinical treatment of PsA in Latin America. The Group for Research and Assessment of Psoriasis and PsA (GRAPPA) has an increasing number of members from this region. In a coordinated effort, GRAPPA, the Latin American Psoriasis and PsA Society (LAPPAS), and the Pan American League of Associations for Rheumatology (PANLAR) are supporting clinician researchers with educational initiatives in Latin America to understand these conditions.
Publication des données sur la qualité des établissements scolaires au Danemark : contingence et non-linéarité
Authors: Dahler-Larsen Peter
Published: February 2012

Résumé La publication de données sur les résultats des écoles est justifiée par la nécessaire amélioration des performances, de la transparence et de la responsabilité (accountability). Cet article analyse deux points de vue différents sur le cas du Danemark : l’un la justifie par la responsabilité et l’amélioration des performances ; l’autre la critique pour sa visée idéologique qui, sous couvert de responsabiliser les consommateurs de façon démocratique, redéfinit l’école. L’article fait état de la réticence politique danoise à publier des données perçues comme une forme de punition ou de menace envers les établissements scolaires. Enfin, il examine le point de vue défendu par Stehr qui souligne le rôle de la contingence et de la non-linéarité.
À contre-courant : dépendance au sentier, convergence et contingence. Vers une meilleure compréhension du modèle finlandais d'assurance-qualité et d'évaluation
Authors: Simola Hannu , Varjo Janne , Rinne Risto
Published: February 2012

Résumé Cet article tente d’associer les concepts de dépendance au sentier, de convergence et de contingence pour expliquer le caractère particulier de la politique éducative finlandaise depuis le début des années 1990. Il porte sur l’assurance-qualité et l’évaluation dans l’enseignement secondaire pour tous. L’explicitation et la définition de l’environnement du modèle finlandais d’assurance-qualité et d’évaluation se fondent sur l’analyse de différentes pratiques internationales d’assurance-qualité et d’évaluation, parfois ambiguës, et sur leur réception et leur médiation en Finlande.
L'autoévaluation des établissements scolaires en Écosse
Authors: Grek Sotiria , Ozga Jenny
Published: February 2012

Résumé À partir du texte fondateur “Que vaut notre école ?” (How Good Is Our School?) et des pratiques d’autoévaluation, l’article analyse le rôle des inspecteurs dans le suivi des performances du système scolaire écossais et les enseignements qu’ils en tirent. Un suivi du système par les données a été progressivement remplacé par un type de gouvernance fondé sur l’autoévaluation. Ce processus ne marque pas pour autant l’abandon des indicateurs et critères comparatifs (benchmarks) de performance mais montre leur utilisation davantage comme un fondement de pratiques d’autoévaluation.
Les ressources symboliques des managers scolaires. Essai de typologie
Authors: Baluteau François
Published: February 2012

Résumé En France, le gouvernement de l’école par les résultats a redéfini le rôle du personnel de direction des établissements secondaires, mettant en avant la figure du manager censé construire une organisation performante. Cette recomposition a complexifié la question du changement puisqu’il est désormais plus à concevoir dans les établissements qu’à appliquer selon des règles bureaucratiques. Cet article montre, à partir de quarante-deux entretiens semi-directifs avec des directeurs, la diversité des ressources de type symbolique mobilisées par ces cadres dans le management des établissements secondaires (collège, lycée). Au travers des questions de mixité sociale, de politique pédagogique et de mobilisation des enseignants, sous la responsabilité de ces directeurs, l’étude dresse un répertoire de ressources hétéroclites, voire contradictoires, de natures institutionnelle et stratégique.
Primary School Challenges in the Rural Areas of Finland, France and Portugal
Authors: Ferreira Jorge
Published: February 2012

Résumé Comment la France, la Finlande et le Portugal définissent-ils et gèrent-ils le maillage des écoles primaires en milieu rural ? Quel degré d’autonomie chaque pays accorde-t-il aux autorités locales pour organiser l’école ? Ces questions ont amené l’auteur à une analyse des instructions officielles dont la comparaison révèle l’opposition entre la très forte décentralisation finlandaise et un système centralisé caractérisé au Portugal. La France apparaît dans une position médiane. L’article montre que les choix politiques de l’État influent sur la typologie des modes d’organisation des établissements. Alors qu’en Finlande et en France plusieurs modèles coexistent, un seul s’impose au Portugal.
Exode des cerveaux en Afrique : réalités et déconstruction du discours sur un phénomène social
Authors: Maingari Daouda
Published: February 2012

Résumé Après deux décennies de fonctionnement où les diplômés, toutes filières confondues, obtenaient facilement un emploi après leurs études, le plein-emploi s’est essoufflé dans les années 1980 et surtout 1990 avec la crise économique. La dégression de l’effectif des personnels de l’État –incitation à la retraite anticipée, gel des recrutements– a entraîné la sédentarisation des étudiants dans le pays où ils faisaient leurs études ou leur émigration. Selon l’UNESCO, plus de 30 000 Africains titulaires d’un diplôme de 3 e cycle universitaire vivraient en dehors du continent et 25 000 boursiers venus faire leurs études dans l’Union européenne n’auraient pas regagné leur pays d’origine. Trouver des solutions à cette hémorragie des ressources humaines interpelle à la fois les politiques et les scientifiques dans un environnement international marqué par la mobilité des cerveaux et l’émergence de la société de la connaissance.
Les enjeux de l'accès à l'eau en Afrique de l'Ouest : diversité des modes de gouvernance et conflits d'usages
Authors: Baron Catherine , Bonnassieu Alain
Published: February 2012

Les modes de gouvernance des services d’eau potable préconisés à l’échelle globale sont fondés sur des partenariats entre entités publiques nationales ou locales, opérateurs privés et associations d’usagers. Faible prise en compte, par les structures de développement, des représentations et pratiques endogènes de gestion de l’accès à l’eau potable dans les sociétés africaines. Dans un contexte d’accroissement de la demande et de difficultés à financer l’investissement et la maintenance des infrastructures, le manque de capacités et/ou de volonté des populations à payer l’eau entrave la construction de marchés locaux de l’eau.
Le coton bio-équitable au Mali : un facteur de transformation sociale pour les femmes ?
Authors: Droy Isabelle
Published: February 2012

La production de coton biologique et équitable a démarré depuis 2004 au Mali dans un contexte de grave crise du système de production du coton conventionnel. Cette alternative a rencontré une forte adhésion, notamment auprès des femmes ; leurs nouvelles responsabilités en tant que productrices contribuent à une valorisation de leur statut social. Cependant, sans réduction des inégalités d’accès des femmes à la terre, à l’équipement agricole et à la main-d’œuvre, la durabilité de la filière risque d’être compromise.
Quels acteurs pour un développement socialement soutenable autour du lac Horo (Nord Mali) ?
Authors: Adamczewski Amandine , Hertzog Thomas , Lallau Benoît
Published: February 2012

L’article étudie les conditions d’un développement socialement soutenable autour du lac Horo. Dans cette zone lacustre du Nord Mali qui concentre une population importante et diversifiée naissent des conflits pour l’accès aux ressources naturelles. Plutôt que de raisonner en termes de “tragédie des communs”, nous étudions les stratégies d’adaptation des ménages et entrons dans la boîte noire des communautés et des dynamiques collectives. Ceci permet d’envisager les voies d’un développement articulant une résilience des moyens d’existence des ménages et des modes collectifs efficaces de gestion des ressources.
La lutte contre les inégalités au Brésil : une analyse critique de l'action du gouvernement de Lula
Authors: Gaulard Mylène
Published: February 2012

Après avoir été longtemps désigné comme l’un des pays les plus inégalitaires au monde, le Brésil connaît depuis la seconde moitié des années 1990 une diminution de ses inégalités de revenus. La baisse des inégalités régionales est, comme celle des inégalités de revenus, le résultat du processus de désindustrialisation dans lequel est entré le pays depuis la fin des années 1980. Contrairement à ce qui est parfois affirmé, l’arrivée du Président Lula au pouvoir en 2003 ne peut expliquer cette évolution.
Are conditional cash grants fair ? The meta-operative model
Authors: Dobra Alexandra
Published: February 2012

L’article évalue l'équité du système de subventions conditionnelles via une approche de gestion des risques sociaux, en se concentrant sur Bolsa Familia au Brésil et Oportunidades au Mexique. En considérant le fonctionnement variable de ces programmes, leur injustice est mise en évidence au niveau de leurs dimensions opérationnelles et de leurs résultats. Dans le but de s'attaquer à l'origine de l'injustice de subventions conditionnelles, l'auteur a développé le modèle meta-operatif.
Commerce international et incertitudes sur les effets environnementaux et sanitaires des biens. Les négociations autour du bœuf aux hormones et des OGM.
Authors: Lupton Sylvie
Published: February 2012

Résumé Ce papier centre son attention sur deux études de cas : celle du bœuf aux hormones et celle des OGM (Organismes Génétiquement Modifiés). Nous montrerons les similarités et différences dans les négociations (tentative d’éviter les conflits, existence de règles parallèles, issue des conflits) dans le cadre de l’OMC. Enfin, nous proposerons une grille théorique pour comprendre la complexité de ces négociations à travers le concept d’institutions parallèles et de biens indéterminés.
Les défis de la MESORE
Authors: Goovaerts Leo
Published: February 2012

Résumé Trois critiques principales peuvent être adressées à la notion de MESORE : c’est une notion faiblement conceptualisée ; il existe à son sujet un problème de mesure et d’anticipation ; enfin, elle connote une vision statique et ethno-centrée de la négociation. L’auteur propose ici de mieux conceptualiser et objectiver cette notion d’alternative en négociation et d’outiller les négociateurs, en particulier à l’aide de modèles d’évaluation.
Deux concepts de compromis : commun vs analogique
Authors: Nachi Mohamed
Published: February 2012

Résumé Dans cet article, je me suis posé la question de savoir quel serait le lien à établir entre les deux acceptions du terme compromis : commune et analogique. C’est la réponse à cette interrogation qui m’a conduit aux considérations épistémologiques développées ci-après, dont l’ambition est de travailler deux concepts opératoires visant à rendre intelligibles les réalités multiples du compromis.
Shivering Management During Therapeutic Temperature Modulation: Nurses’ Perspective
Authors: Presciutti Mary , Bader Mary Kay , Hepburn Millie
Published: February 2012

Therapeutic temperature modulation, which incorporates mild hypothermia and maintenance of normothermia, is being used to manage patients resuscitated after cardiac arrest. Methods of modulating temperature include intravenous infusion of cold fluids and surface or endovascular cooling. During this therapy, the shiver response is activated as a defense mechanism in response to an altered set-point temperature and causes metabolic and hemodynamic stress for patients. Recognition of shivering according to objective and subjective assessments is vital for early detection of the condition. Once shivering is detected, treatment is imperative to avoid deleterious effects. The Bedside Shivering Assessment Scale can be used to determine the efficacy of interventions intended to blunt thermoregulatory defenses and can provide continual evaluation of patients’ responses to the interventions. Nurses’ knowledge and understanding of the harmful effects of shivering are important to effect care and prevent injury associated with uncontrolled shivering.
National Survey of Central Venous Catheter Flushing in the Intensive Care Unit
Authors: Sona Carrie , Prentice Donna , Schallom Lynn
Published: February 2012

Background

Evidence is needed on the best solution for flushing central venous catheters.

Objective

To understand current flushing practices for short-term central venous catheters among critical care nurses before implementation of a randomized, controlled trial comparing physiological saline with heparin solution for flushing to maintain catheter patency.

Methods

A 6-item survey including demographic data was mailed to 2000 practicing critical care nurses in the United States. An additional 316 surveys were completed at the annual conference of the American Association of Critical-Care Nurses.

Results

Most (71.5%) of the 632 respondents who completed the survey were staff nurses. Most respondents (64.6%; 95% CI, 60.86%–68.34%) reported using physiological saline exclusively to flush central venous catheters and maintain patency. For heparin-containing solutions, the concentration and volume used varied. The most commonly reported volumes for flushing were 10 mL for saline (63%; 95% CI, 59.18%–66.82%) and 3 mL for heparin (50.2%; 95% CI, 43.5%–56.9%).

Conclusion

Flushing practices for central venous catheters vary widely. A randomized controlled trial is needed to determine the optimal flushing solution to maintain short-term patency.
Patients and Their Families Weigh in on Evidence-Based Hospital Design
Authors: Trochelman Kathleen , Albert Nancy , Spence Jacqueline , Murray Terri , Slifcak Ellen
Published: February 2012

Background

In 2 landmark publications, the Institute of Medicine reported on significant deficiencies in our current health care system. In response, an area of research examining the role of the physical environment in influencing outcomes for patients and staff gained momentum. The concept of evidence-based design has evolved, and the development of structural guidelines for new hospital construction was instituted by the American Institute of Architects in 2006.

Objective

To determine perceptions of patients and their families of evidence-based design features in a new heart center.

Methods

Hospitalized patients and their families, most of whom were in intensive care and step-down units, were surveyed and data from the Hospital Consumer Assessment of Healthcare Providers and Systems were reviewed to determine perceptions of evidence-based design features incorporated into a new heart center and to assess patients’ satisfaction with the environment.

Results

Responses were reviewed and categorized descriptively. Five general environment topics of focus emerged: privacy, space, noise, light, and overall atmosphere. Characteristics perceived as being dissatisfying and satisfying are discussed.

Conclusions

Critical care nurses must be aware of the current need to recognize how much the physical environment influences care delivery and take steps to maximize patients’ safety, satisfaction, and quality of care.
Hospitalized Infants Who Hurt: A Sweet Solution With Oral Sucrose
Authors: Pasek Tracy Ann , Huber Jessica Marie
Published: February 2012

Pain is harmful to newborn infants. Oral sucrose is safe, inexpensive, and effective at preventing and reducing pain in hospitalized babies who undergo invasive procedures. The sugar can be used alone or in combination with analgesics and other nonpharmacological interventions to provide analgesia. Parents expect nurses to serve as pain advocates for the parents’ newborns and to protect the babies from needless suffering. It is incumbent upon nurses to stay abreast of the current evidence and integrate use of oral sucrose into daily pain management practice in emergency, acute, and critical care units.
Adoption Of Improved Potato Varieties In Nepal: A Case Of Bara District
Authors: Kafle B , Shah P
Published: February 2012

The study examines the determinants of adoption of improved potato varieties in Bara district of Nepal. Data was obtained from 51 potato farmers through the use of structured questionnaires. The study employed descriptive statistics and regression analysis to assess adoption status and its determinants. The results of the regression analysis showed that household size has negative influence on adoption of improved potato varieties while land tenancy, cattle ownership, contact with extension agents, age and level of education have positive influences. It is recommended that adult education should be provided to the adult farmers and the number of extension agents should be increased who would help introduce new potato varieties and improve technical and managerial skills of farmers through improved extension services. DOI: http://dx.doi.org/10.4038/jas.v7i1.4063 JAS 2012 7(1): 14-22
Socio-Economic Factors Influencing The Adoption Of Hybrid Maize In Giwa Local Government Area Of Kaduna State, Nigeria
Authors: Ebojei CO , Ayinde TB , Akogwu GO
Published: February 2012

Maize (Zea mays L.) is one of the most important cereal crops in Nigerian agriculture. The crop occupies a crucial place than other cereal crops since it is used as food, feed, fodder and other industrial raw material. The aim of this study is to identify the socio-economic factors that influence farmers’ decision to adopt hybrid maize in Giwa Local Government Area of Kaduna state, Nigeria using the farm household survey data collected from 160 maize farmers in October- December 2009 for the cropping year 2009-10. This paper presents the results of an empirical application of maximum likelihood estimate of Logit Model to determine the factors influencing farmers’ adoption of hybrid maize. The results indicates that the mean predicted probability of technology adoption was Age (X1) (P<0.013), income (X5) (p<0.034), education (X6) (p<0.001) and extension visits (X7) (P<0.017). On the contrary, farming experience, family size, farm size had no significant influence on participation in hybrid maize. This study suggests the need to bring more area under hybrid maize cultivation. Furthermore, there is a need for special training, seminars, field demonstrations and technical support for the maize farmers. As most of the households had no formal education, the extension program should be intended to the less educated farmers. In addition, the credit facility particularly the procedure for loan should be made simple to improve the adoption rate of hybrid maize in the study area. DOI: http://dx.doi.org/10.4038/jas.v7i1.4064 JAS 2012 7(1): 23-32
Effect Of Small-Scale Irrigation On The Income Of Rural Farm Households: The Case Of Laelay Maichew District, Central Tigray, Ethiopia
Authors: Aseyehegu Kinfe , Yirga Chilot , Rajan Sundar
Published: February 2012

Agricultural intensification is presumed to be a necessary pre-condition for the development of the agricultural sector in Ethiopia. To this end, various government and non-governmental organizations (NGOs), among others, initiated small-scale irrigation schemes throughout the country including the Tigray region. Despite these efforts, however, smallholder farmers particularly in the study area are found to be reluctant to participate in small-scale irrigation schemes. This study therefore, assessed the factors that affect smallholder farmers’ participation in small-scale irrigation of the study area. It also explored the effect of participation in small-scale irrigation on the income of rural farm households. A two-stage sampling procedure was used to first select peasant associations and then sample respondents. Descriptive statistics and Heckman’s two-stage estimation were used to estimate determinants of small-scale irrigation participation and household income. The analysis revealed that income, gender, access to market information and health condition of households are important determinants for participating in small scale irrigation schemes. The analysis further revealed that irrigation participation, family labor force, livestock ownership and access to market information and credit are positively and significantly associated with household income. Hence, improving rural farm households’ access to market information and health services, is likely to improve participation in irrigation schemes thereby improve small holder farmers income. DOI: http://dx.doi.org/10.4038/jas.v7i1.4066 JAS 2012 7(1): 43-57
Overcoming the Effects of Matrix Interference in the Measurement of Urine Protein Analytes
Authors: Taylor Timothy P. , Janech Michael G. , Slate Elizabeth H. , Lewis Evelyn C. , Arthur John M. , Oates Jim C
Published: February 2012

Using multiplex bead assays to measure urine proteins has a great potential for biomarker discovery, but substances in urine (the matrix) can interfere with assay measurements. By comparing the recovery of urine spiked with known quantities of several common analytes, this study demonstrated that the urine matrix variably interfered with the accurate measurement of low abundance proteins. Dilution of the urine permitted a more accurate measure of these proteins, equivalent to the standard dilution technique when the diluted analytes were above the limits of detection of the assay. Therefore, dilution can be used as an effective technique for overcoming urine matrix effects in urine immunoassays. These results may be applicable to other biological fluids in which matrix components interfere with assay performance.
Detection of 1p19q Deletion by Real-Time Comparative Quantitative PCR
Authors: Chaturbedi Abhishek , Yu Liping , Linskey Mark E , Zhou Yi-hong
Published: February 2012

1p/19q (1p and/or 19q) deletions are prognostic factors in oligodendroglial tumors (OT) and predict better survival after both chemotherapy and radiotherapy. While studying 1p/19q status as a potential variable within multivariate prognosis models for OT, we have frequently encountered unknown 1p/19q status within our glioma sample database due to lack of paired blood samples for loss of heterozygosity (LOH) assay and/or failure to perform fluorescence in situ hybridization (FISH). We realized that a 1p and 19q deletion assay that could be reliably performed solely on tumor DNA samples would allow us to fill in these molecular biology data “holes”. We built recombinant DNA with fragments of the selected “marker” genes in 1p ( E2 F2, NOTCH2), and 19q ( PLAUR) and “reference” genes ( ERC2, SPOCK1, and SPAG16) and used it as quantification standard in real-time PCR to gain absolute ratios of marker/reference gene copy numbers in tumor DNA samples, thus called comparative quantitative PCR (CQ-PCR). Using CQ-PCR, we identified 1p and/or 19q deletions in majority of pure low-grade oligodenroglioma (OG) tumors (17/21, 81%), a large portion of anaplastic oligodendro% of mixed oligodendroglioma (AO) tumors (6/15, 47%), but rarely found in mixed oligoastrcytomas (OA) tumors (1/8, 13%). These data are consistent with results of LOH and FISH assays generally reported for these tumor types. In addition, 15 out 18 samples showed concordant results between FISH and CQ-PCR. We conclude that CQ-PCR is a potential means to gain 1p/19q deletion information, which prognostic and predictive values of CQ-PCR-derived 1p/19q status will be determined in a future study.
Clinical Efficacy of Vorinostat in a Patient with Leiomyosarcoma
Authors: Lee Jin , Mcguire Colin
Published: February 2012

Leiomyosarcoma is a heterogeneous tumor group, representing <1% of all new cancers diagnosed in United States. Treatment choice is based upon site, grade, and extent of disease. However, prognosis for metastatic or unresectable sarcoma is very poor with reported median survival of 12 months. Response to chemotherapy has been approximately 8% to 39% based upon the chemotherapeutic agent and whether used alone or in combination. Vorinostat is an orally active, potent, and competitive inhibitor of histone deacetylases approved for cutaneous T-cell lymphoma. There are limited preclinical data illustrating the activity of histone deacetylase inhibitors in sarcoma. Here is a case of a lady with leiomyosarcoma who has progressed through multiple chemotherapeutic agent who has achieved a partial response to vorinostat treatment.
Short-lived brominated hydrocarbons – observations in the source regions and the tropical tropopause layer
Authors: Brinckmann S. , Engel A. , Bönisch H. , Quack B. , Atlas E.
Published: February 2012

Abstract. We conducted measurements of the five important short-lived organic bromine species in the marine boundary layer (MBL). Measurements were made in the Northern Hemisphere mid-latitudes (Sylt Island, North Sea) in June 2009 and in the tropical Western Pacific during the TransBrom ship campaign in October 2009. For the one-week time series on Sylt Island, mean mixing ratios of CHBr3, CH2Br2, CHBr2Cl and CH2BrCl were 2.0, 1.1, 0.2, 0.1 ppt, respectively. We found maxima of 5.8 and 1.6 ppt for the two main components CHBr3 and CH2Br2. Along the cruise track in the Western Pacific (between 41° N and 13° S) we measured mean mixing ratios of 0.9, 0.9, 0.2, 0.1 and 0.1 ppt for CHBr3, CH2Br2, CHBrCl2, CHBr2Cl and CH2BrCl. Air samples with coastal influence showed considerably higher mixing ratios than the samples with open ocean origin. Correlation analyses of the two data sets yielded strong linear relationships between the mixing ratios of four of the five species (except for CH2BrCl). Using a combined data set from the two campaigns and a comparison with the results from two former studies, rough estimates of the molar emission ratios between the correlated substances were: 9/1/0.35/0.35 for CHBr3/CH2Br2/CHBrCl2/CHBr2Cl. Additional measurements were made in the tropical tropopause layer (TTL) above Teresina (Brazil, 5° S) in June 2008, using balloon-borne cryogenic whole air sampling technique. Near the level of zero clear-sky net radiative heating (LZRH) at 14.8 km about 2.25 ppt organic bromine was bound to the five short-lived species, making up 13% of total organic bromine (17.82 ppt). CH2Br2 (1.45 ppt) and CHBr3 (0.56 ppt) accounted for 90% of the budget of short-lived compounds in that region. Near the tropopause (at 17.5 km) organic bromine from these substances was reduced to 1.35 ppt, with 1.07 and 0.12 ppt attributed to CH2Br2 and CHBr3, respectively.
The role of carbonyl sulphide as a source of stratospheric sulphate aerosol and its impact on climate
Authors: Brühl C. , Lelieveld J. , Crutzen P. J. , Tost H.
Published: February 2012

Abstract. Globally, carbonyl sulphide (COS) is the most abundant sulphur gas in the atmosphere. Our chemistry-climate model (CCM) of the lower and middle atmosphere with aerosol module realistically simulates the background stratospheric sulphur cycle, as observed by satellites in volcanically quiescent periods. The model results indicate that upward transport of COS from the troposphere largely controls the sulphur budget and the aerosol loading of the background stratosphere. This differs from most previous studies which indicated that short-lived sulphur gases are also important. The model realistically simulates the modulation of the particulate and gaseous sulphur abundance in the stratosphere by the quasi-biennial oscillation (QBO). In the lowermost stratosphere organic carbon aerosol contributes significantly to extinction. Further, using a chemical radiative convective model and recent spectra, we compute that the direct radiative forcing efficiency by 1 kg of COS is 724 times that of 1 kg CO2. Considering an anthropogenic fraction of 30% (derived from ice core data), this translates into an overall direct radiative forcing by COS of 0.003 W m−2. The direct global warming potentials of COS over time horizons of 20 and 100 yr are GWP(20 yr) = 97 and GWP(100 yr) = 27, respectively (by mass). Furthermore, stratospheric aerosol particles produced by the photolysis of COS (chemical feedback) contribute to a negative direct solar radiative forcing, which in the CCM amounts to −0.007 W m−2 at the top of the atmosphere for the anthropogenic fraction, more than two times the direct warming forcing of COS. Considering that the lifetime of COS is twice that of stratospheric aerosols the warming and cooling tendencies approximately cancel.
Analysis of satellite-derived Arctic tropospheric BrO columns in conjunction with aircraft measurements during ARCTAS and ARCPAC
Authors: Choi S. , Wang Y. , Salawitch R. J. , Canty T. , Joiner J. , Zeng T. , Kurosu T. P. , Chance K. , Richter A. , Huey L. G. , Liao J. , Neuman J. A. , Nowak J. B. , Dibb J. E. , Weinheimer A. J. , Diskin G. , Ryerson T. B. , da Silva A. , Curry J. , Kinnison D. , Tilmes S. , Levelt P. F.
Published: February 2012

Abstract. We derive tropospheric column BrO during the ARCTAS and ARCPAC field campaigns in spring 2008 using retrievals of total column BrO from the satellite UV nadir sensors OMI and GOME-2 using a radiative transfer model and stratospheric column BrO from a photochemical simulation. We conduct a comprehensive comparison of satellite-derived tropospheric BrO column to aircraft in-situ observations of BrO and related species. The aircraft profiles reveal that tropospheric BrO, when present during April 2008, was distributed over a broad range of altitudes rather than being confined to the planetary boundary layer (PBL). Perturbations to the total column resulting from tropospheric BrO are the same magnitude as perturbations due to longitudinal variations in the stratospheric component, so proper accounting of the stratospheric signal is essential for accurate determination of satellite-derived tropospheric BrO. We find reasonably good agreement between satellite-derived tropospheric BrO and columns found using aircraft in-situ BrO profiles, particularly when satellite radiances were obtained over bright surfaces (albedo >0.7), for solar zenith angle <80° and clear sky conditions. The rapid activation of BrO due to surface processes (the bromine explosion) is apparent in both the OMI and GOME-2 based tropospheric columns. The wide orbital swath of OMI allows examination of the evolution of tropospheric BrO on about hourly time intervals near the pole. Low surface pressure, strong wind, and high PBL height are associated with an observed BrO activation event, supporting the notion of bromine activation by high winds over snow.
Examination of aerosol distributions and radiative effects over the Bay of Bengal and the Arabian Sea region during ICARB using satellite data and a general circulation model
Authors: Cherian R. , Venkataraman C. , Ramachandran S. , Quaas J. , Kedia S.
Published: February 2012

Abstract. In this paper we analyse aerosol loading and its direct radiative effects over the Bay of Bengal (BoB) and Arabian Sea (AS) regions for the Integrated Campaign on Aerosols, gases and Radiation Budget (ICARB) undertaken during 2006, using satellite data from the MODerate Resolution Imaging Spectroradiometer (MODIS) on board the Terra and Aqua satellites, the Aerosol Index from the Ozone Monitoring Instrument (OMI) on board the Aura satellite, and the European-Community Hamburg (ECHAM5.5) general circulation model extended by Hamburg Aerosol Module (HAM). By statistically comparing with large-scale satellite data sets, we firstly show that the aerosol properties measured during the ship-based ICARB campaign and simulated by the model are representative for the BoB and AS regions and the pre-monsoon season. In a second step, the modelled aerosol distributions were evaluated by a comparison with the measurements from the ship-based sunphotometer, and the satellite retrievals during ICARB. It is found that the model broadly reproduces the observed spatial and temporal variability in aerosol optical depth (AOD) over BoB and AS regions. However, AOD was systematically underestimated during high-pollution episodes, especially in the BoB leg. We show that this underprediction of AOD is mostly because of the deficiencies in the coarse mode, where the model shows that dust is the dominant component. The analysis of dust AOD along with the OMI Aerosol Index indicate that missing dust transport that results from too low dust emission fluxes over the Thar Desert region in the model caused this deficiency. Thirdly, we analysed the spatio-temporal variability of AOD comparing the ship-based observations to the large-scale satellite observations and simulations. It was found that most of the variability along the track was from geographical patterns, with a minor influence by single events. Aerosol fields were homogeneous enough to yield a good statistical agreement between satellite data at a 1° spatial, but only twice-daily temporal resolution, and the ship-based sunphotometer data at a much finer spatial, but daily-average temporal resolution. Examination of the satellite data further showed that the year 2006 is representative for the five-year period for which satellite data were available. Finally, we estimated the clear-sky solar direct aerosol radiative forcing (DARF). We found that the cruise represents well the regional-seasonal mean forcings. Constraining simulated forcings using the observed AOD distributions yields a robust estimate of regional-seasonal mean DARF of −8.6, −21.4 and +12.9 W m−2 at the top of the atmosphere (TOA), at the surface (SUR) and in the atmosphere (ATM), respectively, for the BoB region, and over the AS, of, −6.8, −12.8, and +6 W m−2 at TOA, SUR, and ATM, respectively.
A mechanistic model of global soil nitric oxide emissions: implementation and space based-constraints
Authors: Hudman R. C. , Moore N. E. , Martin R. V. , Russell A. R. , Mebust A. K. , Valin L. C. , Cohen R. C.
Published: February 2012

Abstract. Soil emissions have been identified as a major source (~15%) of global nitrogen oxide (NOx) emissions. Parameterizations of soil NOx emissions (SNOx) for use in the current generation of chemical transport models were designed to capture mean seasonal behaviour. These parameterizations do not, however, respond quantitatively to the meteorological triggers that result in pulsed SNOx as are widely observed. Here we present a new mechanistic parameterization of SNOx implemented into a global chemical transport model (GEOS-Chem). The parameterization represents available nitrogen (N) in soils using biome specific emission factors, online wet- and dry-deposition of N as well as fertilizer and manure N derived from a spatially explicit dataset distributed using seasonality derived from data obtained by the Moderate Resolution Imaging Spectrometer. Moreover, it represents the functional form of emissions derived from point measurements and ecosystem scale experiments including pulsing following soil wetting by rain or irrigation, and emissions that are a smooth function of soil moisture. This parameterization yields global above-soil SNOx of 10.7 Tg N yr−1, including 1.8 Tg N yr−1 from fertilizer N input (0.68% of applied N) and 0.5 Tg N yr−1 from atmospheric N deposition. Over the United States Great Plains, SNOx are predicted to comprise 15–40% of the tropospheric NO2 column and increase column variability by a factor of 2–4 during the summer months due to chemical fertilizer application and warm temperatures. SNOx enhancements of 50–80% of the simulated NO2 column are predicted over the African Sahel during the monsoon onset (April–June). In this region the day-to-day variability of column NO2 is increased by a factor of 5 due to pulsed-N emissions. We evaluate the model by comparison to observations of the NO2 column from the OMI instrument. We find the model is able to reproduce observations of pulsed-N induced interannual variability over the US Great Plains. We also show that the OMI mean (median) NO2 on the overpass following first rainfall over the Sahel is 49% (23%) higher than in the five days preceding. The measured NO2 on the day after rainfall is still 23% (5%) higher, providing a direct measure of the pulse's decay time of 1–2 days. This is consistent with the pulsing representation used in our parameterization and much shorter than 5–14 day pulse decay length used in current models.
Correcting orbital drift signal in the time series of AVHRR derived convective cloud fraction using rotated empirical orthogonal function
Authors: Devasthale A. , Karlsson K.-G. , Quaas J. , Grassl H.
Published: February 2012

Abstract. The Advanced Very High Resolution Radiometer (AVHRR) instruments onboard the series of National Oceanic and Atmospheric Administration (NOAA) satellites offer the longest available meteorological data records from space. These satellites have drifted in orbit resulting in shifts in the local time sampling during the life span of the sensors onboard. Depending upon the amplitude of the diurnal cycle of the geophysical parameters derived, orbital drift may cause spurious trends in their time series. We investigate tropical deep convective clouds, which show pronounced diurnal cycle amplitude, to estimate an upper bound of the impact of orbital drift on their time series. We carry out a rotated empirical orthogonal function analysis (REOF) and show that the REOFs are useful in delineating orbital drift signal and, more importantly, in subtracting this signal in the time series of convective cloud amount. These results will help facilitate the derivation of homogenized data series of cloud amount from NOAA satellite sensors and ultimately analyzing trends from them. However, we suggest detailed comparison of various methods and rigorous testing thereof applying final orbital drift corrections.
Features of the seasonal variation of the semidiurnal, terdiurnal and 6-h components of ozone heating evaluated from Aura/MLS observations
Authors: Xu J. , Smith A. K. , Jiang G. , Yuan W. , Gao H.
Published: February 2012

Abstract. This paper presents the thermal forcing of the semidiurnal, terdiurnal, and 6-h components of the migrating tide induced by ozone heating in stratosphere and lower mesosphere. The heating as a function of local time is determined from the global ozone observed by the Microwave Limb Sounder on the Aura satellite. The harmonic components of the heating rates of the semidiurnal, terdiurnal and the 6-h periodicities are calculated using the Strobel/Zhu parameterized model and then decomposed into Hough modes. Seasonal variations of each harmonic component and its Hough modes are presented. For all three tidal components, the majority of the annual mean O3 heating projects onto symmetric modes. The semiannual variation is a prominent signal in almost all of the symmetric Hough modes near the stratopause. The strongest annual variation takes place in the asymmetric modes. The results also show that, during the solstice season, the maximum forcing of the diurnal and terdiurnal component occurs in the summer hemisphere while the maximum forcing of the semidiurnal and 6-h components occurs in the winter hemisphere. The global mean ozone density and the tidal components of the ozone heating rate are different between December–January and June–July. The asymmetry in the heating is primarily due to the 6.6% annual variation in the solar energy input into the Earth's atmosphere due to the annual variation of the Sun-Earth distance.
Carbon dioxide emissions from an Acacia plantation on peatland in Sumatra, Indonesia
Authors: Jauhiainen J. , Hooijer A. , Page S. E.
Published: February 2012

Abstract. Peat surface CO2 emission, groundwater table depth and peat temperature were monitored for two years along transects in an Acacia plantation on thick tropical peat (>4 m) in Sumatra, Indonesia. A total of 2300 emission measurements were taken at 144 locations, over a 2 year period. The autotrophic root respiration component of CO2 emission was separated from heterotrophic emission caused by peat oxidation in three ways: (i) by comparing CO2 emissions within and beyond the tree rooting zone, (ii) by comparing CO2 emissions with and without peat trenching (i.e. cutting any roots remaining in the peat beyond the tree rooting zone), and (iii) by comparing CO2 emissions before and after Acacia tree harvesting. On average, the contribution of autotrophic respiration to daytime CO2 emission was 21% along transects in mature tree stands. At locations 0.5 m from trees this was up to 80% of the total emissions, but it was negligible at locations more than 1.3 m away. This means that CO2 emission measurements well away from trees were free of any autotrophic respiration contribution and thus represent only heterotrophic emissions. We found daytime mean annual CO2 emission from peat oxidation alone of 94 t ha−1 y−1 at a mean water table depth of 0.8 m, and a minimum emission value of 80 t ha−1 y−1 after correction for the effect of diurnal temperature fluctuations, which may result in a 14.5% reduction of the daytime emission. There is a positive correlation between mean long-term water table depth and peat oxidation CO2 emission. However, no such relation is found for instantaneous emission/water table depth within transects and it is clear that factors other than water table depth also affect peat oxidation and total CO2 emissions. The increase in the temperature of the surface peat due to plantation establishment may explain over 50% of peat oxidation emissions. Our study sets a standard for greenhouse gas flux studies from tropical peatlands under different forms of agricultural land management. It is the first to purposefully quantify heterotrophic CO2 emissions resulting from tropical peat decomposition by separating these from autotrophic emissions. It also provides the most scientifically- and statistically-rigorous study to date of CO2 emissions resulting from anthropogenic modification of this globally significant carbon rich ecosystem. Our findings indicate that past studies have underestimated emissions from peatland plantations, with important implications for the scale of greenhouse gas emissions arising from land use change, particularly in the light of current, rapid agricultural conversion of peatlands in the Southeast Asian region.
The effect of atmospheric turbulence and chamber deployment period on autochamber CO2 and CH4 flux measurements in an ombrotrophic peatland
Authors: Lai D. Y. F. , Roulet N. T. , Humphreys E. R. , Moore T. R. , Dalva M.
Published: February 2012

Abstract. Accurate quantification of soil-atmosphere gas exchange is essential for understanding the magnitude and controls of greenhouse gas emissions. We used an automatic closed dynamic chamber system to measure the fluxes of CO2 and CH4 for several years at the ombrotrophic Mer Bleue peatland near Ottawa, Canada and found that atmospheric turbulence and chamber deployment period had a considerable influence on the observed flux rates. With a short deployment period of 2.5 min, CH4 flux exhibited strong diel patterns and both CH4 and nighttime CO2 effluxes were highly and negatively correlated with friction velocity as were the CO2 concentration gradients in the top 20 cm of peat. This suggests winds were flushing the very porous and relatively dry near surface peat layers, altering the concentration gradient and resulting in a 9 to 57% underestimate of CH4 flux at any time of day and a 13 to 21% underestimate of nighttime CO2 fluxes in highly turbulent conditions. Conversely, there was evidence of an overestimation of ~100% of CH4 and nighttime CO2 effluxes in calm atmospheric conditions possibly due to enhanced near-surface gas concentration gradient by mixing of chamber headspace air by fans. These problems were resolved by extending the deployment period to 30 min. After 13 min of chamber closure, the flux rate of CH4 and nighttime CO2 became constant and were not affected by turbulence thereafter, yielding a reliable estimate of the net biological fluxes. The measurement biases we observed likely exist to some extent in all chamber flux measurements made on porous and aerated substrate, such as peatlands, organic soils in tundra and forests, and snow-covered surfaces, but would be difficult to detect unless high frequency, semi-continuous observations are made.
Training hydrologists to be ecohydrologists and play a leading role in environmental problem solving
Authors: McClain M. E. , Chícharo L. , Fohrer N. , Gaviño Novillo M. , Windhorst W. , Zalewski M.
Published: February 2012

Abstract. Ecohydrology is a relatively new and rapidly growing subject area in the hydrology curriculum. It is a trans-disciplinary science derived from the larger earth systems science movement and examining mutual interactions of the hydrological cycle and ecosystems. It is also an applied science focused on problem solving and providing sound guidance to catchment-scale integrated land and water resources management. The principle spheres of ecohydrology include (i) climate-soil-vegetation-groundwater interactions at the land surface with special implications for land use, food production and climate change; (ii) riparian runoff, flooding, and flow regime dynamics in river corridors with special implications for water supply, water quality, and inland fisheries; and (iii) fluvial and groundwater inputs to lakes/reservoirs, estuaries, and coastal zones with special implications for water quality and fisheries. We propose an educational vision focused on the development of professional and personal competencies to impart a depth of scientific knowledge in the theory and practice of ecohydrology and a breadth of cross-cutting knowledge and skills to enable ecohydrologists to effectively collaborate with associated scientists and communicate results to resource managers, policy-makers, and other stakeholders. In-depth knowledge in hydrology, ecology, and biogeochemistry is emphasized, as well as technical skills in data collection, modeling, and statistical analysis. Cross-cutting knowledge is framed in the context of integrated water resources management. Personal competencies to be fostered in educational programs include creative thinking, cooperation, communication, and leadership. We consider a life-long learning context but highlight the importance of master's level training in the professional formation of ecohydrologists.