bluuebunny/crossref_metadata_2025 huggingface dataset:
Figurines anthropomorphes du Bronze ancien de Shahr-i Sokhta, période II (Séistan, Sud-Est de l’Iran) : approche typologique
Authors: Shirazi Rouhollah
Published: March 2011

Résumé: Situé le long de la route de Zabol à Zahedan, dans la région du Séistan au sud-est de l’Iran, Shahr-i Sokhta est l’un des plus grands sites de l’époque protohistorique de la partie orientale du Plateau iranien. Cet article présente les résultats de l’étude des fi gurines anthropomorphes en terre crue et des «idoles» en pierre retrouvées à Shahr-i Sokhta, mises au jour lors des fouilles récentes effectuées sur la zone monumentale et le quartier dit «des artisans», localisé au nord-ouest du site. Elles sont datées de la première moitié du troisième millénaire av. J.-C. (2800-2500 av. J.-C.). Les représentations debout se distinguent de celles assises, auxquelles s’ajoutent les torses présentant différentes positions des bras et des têtes. Des parallèles sont alors faits avec des figurines retrouvées sur des sites d’Asie centrale et du Baluchistan pakistanais. Ces objets sont probablement liés aux croyances des agro-pasteurs de Shahr-i Sokhta dont l’économie s’intégrait dans les échanges régionaux.
Young Adults in the Workplace: A Multisite Initiative of Substance Use Prevention Programs
Authors: Bray Jeremy , Galvin Deborah , Cluff Laurie
Published: March 2011

The Substance Abuse and Mental Health Services Administration funded the multisite Young Adults in the Workplace (YIW) initiative to study the effectiveness of diverse approaches to workplace-based prevention of substance abuse. Six teams adapted evidence-based programs to target young employees and then implemented the programs in retail, restaurant, health care, construction, skilled trade, and transportation industry workplaces. This book describes the programs, the adaptation and implementation processes, and the YIW cross-site evaluation.
Quelle transmission du « pouvoir militaire » en Afrique ?
Authors: Evrard Camille
Published: March 2011

Résumé « Écouvillon », « Ouragan », « Cornue », « Lamantin », autant de noms évocateurs qui ne désignent qu’une même réalité : des opérations militaires françaises sur le sol mauritanien, entre 1958 et 1978. Elles partagent toutes un caractère confidentiel quoique pour différentes raisons : faibles enjeux pour la métropole, cadre juridique douteux, alliés inavouables et/ou tout simplement classé secret défense. Ces opérations permettent néanmoins de tisser la trame passionnante d’une histoire de la transmission du pouvoir militaire à l’indépendance mauritanienne.
Le rôle de la France après les indépendances
Authors: Bat Jean-Pierre
Published: March 2011

Résumé Si la France s’est officiellement retirée du continent africain après la décolonisation, elle est restée liée à ses anciennes colonies par des accords de défense. À travers la coopération, la présence et l’intervention militaire, mais aussi le renseignement, elle a maintenu des liens privilégiés. À travers le personnage de Foccart et la cellule africaine de l’Élysée, Jean-Pierre Bat analyse la politique de sécurité française en Afrique et démystifie le « système Foccart ».
L'éducation, enjeu majeur de l'Afrique post-indépendances
Authors: Pourtier Roland
Published: March 2011

Résumé Les débats sur l’enseignement au tournant des indépendances soulèvent des questions éminemment politiques. Le choix des matières ou des langues d’enseignement sont le reflet d’un tiraillement entre revendication nationale et héritage colonial. Propos passionnés et études idéologiques sur l’enseignement monopolisent ces débats. Roland Pourtier, à partir des enjeux économiques, sociaux et démographiques, nous propose une analyse rétrospective des débats d’experts au vu des articles consacrés à l’enseignement publiés dans Afrique contemporaine .
Aspects épistémologiques et méthodologiques de la psychodynamique du travail
Authors: Uchida Seiji , Sznelwar Laerte Idal , Lancman Selma
Published: March 2011

Résumé Ce texte contient une proposition de discussion concernant l’évolution des concepts en pdt , portant plus spécialement sur des aspects épistémologiques et des propositions d’action dans son domaine. En partant des questions traitées par la psychopathologie du travail, l’intention est de discuter des différentes étapes de l’évolution du champ en mettant en évidence des inflexions de la pensée de Dejours.
Des femmes au travail pour des femmes en travail : une enquête de psychodynamique du travail avec des sages-femmes
Authors: Saint-Arnaud Louise , Papineau Marie , Marché-Paillé Anne
Published: March 2011

Résumé Une enquête en psychodynamique du travail a été menée auprès d’un collectif de sages-femmes dans un centre de maternité au Québec. Le métier de sages-femmes est passé de la clandestinité au statut de profession. Dans ce contexte du passage à la reconnaissance de ce corps de métier, néanmoins, les sources de souffrance restent nombreuses : épuisement au travail avec une domination mur-à-mur du travail sur le hors-travail, impression d’être « broyées » par un nouveau programme de formation professionnelle exigeant et fort sentiment de non-reconnaissance dans le milieu médical. Pourtant, les sages-femmes sont les témoins intimes du mystère de la femme : procréer, enfanter, lâcher prise, crier, souffrir, perdre contrôle, être vulnérable. Un métier au cœur de l’essence même de ce qu’est le féminin dans sa plus pure expression : porter, bercer, calmer, protéger, donner, ouvrir, permettre, sentir, aimer. L’analyse des savoir-faire et des stratégies défensives de métier a fait ressortir plusieurs paradoxes. Cette étude rend également compte d’une forme de courage « discret » mis en place par les sages-femmes pour tenir l’éthique d’une pratique qu’elles jugent comme étant un lieu privilégié pour construire un monde meilleur.
Le travailleur alcoolique et le système d'évaluation de la performance au travail : une dramaturgie
Authors: Karam Heliete
Published: March 2011

Résumé Cet article présente le cas d’un accident du travail ayant eu lieu dans une compagnie pétrochimique brésilienne. En raison de la complexité de l’événement, il ne délimite comme objet principal d’analyse qu’un seul de ses divers aspects : « le rapport » entre l’employé alcoolique, destiné à rester perpétuellement au bas de la courbe de l’évaluation annuelle des travailleurs et cause directe de l’accident, et les autres employés de l’entreprise. Cet accident a causé d’importants préjudices à l’entreprise, a fait subir de sérieux dommages à l’environnement et a mis en danger la vie des travailleurs et de la communauté. Toutefois, grâce à une certaine façon de travailler avec la parole, proposée par l’auteure, cet accident a entraîné la création d’un espace de discussion qui, à long terme, a transformé l’organisation du travail et le modèle d’évaluation des travailleurs.
A model combining agronomic and weather factors to predict occurrence of deoxynivalenol in durum wheat kernels
Authors: Gourdain E. , Piraux F. , Barrier-Guillot B.
Published: March 2011

Deoxynivalenol (DON) produced by Fusarium graminearum in durum wheat is a major issue for the French food
chain. Since this cereal is exclusively used for human consumption, each batch of grain marketed for first-stage
processing must comply with the DON legal limit of 1,750 µg/kg set by the European Commission. As a response
to this regulation, we have started a study to identify factors affected the DON content in durum wheat kernels.
This study has been made by exploiting data from a field survey started in 2001 in French durum wheat producing
regions. Over 700 field samples were harvested and grains were analysed for their DON content. For each field,
agronomic parameters and weather conditions during flowering were recorded. The study of these parameters has
led to the development of decision-making tools to help farmers manage the risk of DON contamination in the field.
The first stage of the work was to identify critical factors involved in DON content, these being the previous crop,
the tillage practices and the susceptibility of the wheat variety to Fusarium. The combination of these three factors
delimits different crop systems on a DON risk assessment tool which classifies risk categories defined by their risk
level expressed as a percentage probability of exceeding the DON legal limit (from 3% to 60%). Nevertheless, the
main factors involved in Fusarium infection and DON production are the weather conditions prevailing during wheat
flowering. The second stage was to take weather factors into consideration to develop a DON-content predictive
model. The main objective of the model is to predict DON content in grain at harvest time according to the crop
system and weather for the field. For users, in 85% of cases, the model accurately predicted a DON content below
or above the legal limit.
Determination of aflatoxins in commercial nuts and nut products using liquid chromatography tandem mass spectrometry
Authors: Leong Y. , Ismail N. , Latiff A. , Manaf N. , Rosma A.
Published: March 2011

A rapid and sensitive confirmatory analytical method for determination of aflatoxins in nuts and their products
using liquid chromatography tandem mass spectrometry has been developed and validated. All four aflatoxins of
interest (B1, B2, G1 and G2) were quantified using aflatoxin M1 as the internal standard. Samples were extracted using
methanol/water (60:40, v/v) and cleaned-up with immunoaffinity column. Limit of detection ranged between 0.10
and 0.30 µg/kg. Recovery rates were between 76 and 105% for all analytes. For further validation, a reference material
for contaminated peanut has been used for quality assurance measures to check the accuracy and precision. The
method was successfully applied to determine the natural occurrence of aflatoxins in 128 nut samples marketed in
Penang, Malaysia. More than half of the samples (57.0%) were positive and 13.3% were found to be non-compliant
with the European Commission regulations permitted maximum level of 2 µg/kg for aflatoxin B1. The contamination
levels ranged from 0.40 to 221.61 µg/kg for aflatoxin B1 and 0.33 to 273.63 µg/kg for total aflatoxins.
Effect of ochratoxin A on coccidiosis-challenged broiler chicks
Authors: Manafi M. , Mohan K. , Ali M. Noor
Published: March 2011

A study was conducted to evaluate the effects of ochratoxin A (OTA) on broiler chicks challenged with Eimeria
tenella oocysts. Two hundred day-old, unsexed Cobb broiler chicks were randomly divided into four treatment
groups. Each treatment consisted of five replicates and ten chicks per replicate, making the following treatments:
group I: control; group II: OTA (1 mg/kg) daily through feed; group III: coccidia (orally inoculated with 50,000 E.
tenella oocysts/chick on day 21); group IV: OTA (1 mg/kg) daily through feed + coccidia (orally inoculated with
50,000 E. tenella oocysts/chick on day 21). Six birds from each group were slaughtered on the 5th, 7th, 9th and 11th
day post infection. The results showed higher mortality with severe gross lesions in caecum and a greater number
of faecal oocysts in groups III and IV. The gross lesions observed in group IV were characterised by distension of
caecum with blood-tinged content indicative of haemorrhagic typhlitis with mucosal tissue debris. Microscopically,
lymphoid organs revealed severe lymphocytolysis and depletion with cellular sparsity in OTA treated groups.
The increased severity of lesions in the caecum of group IV was attributed to the additive effect of OTA and E.
tenella. Caecum exhibited severe haemorrhages, the presence of numerous second generation schizonts, matured
merozoites and developing oocysts. Group IV showed an increase in the severity of coccidiosis which is due to the
immunosuppressive effect of OTA. Thus, it was concluded that the expression of E. tenella and its pathological
effects were maximum in the presence of OTA compared to the incidence of coccidiosis alone in broiler chicks.
Detection of the seasonal cyclic movement in historic buildings by means of surveying techniques
Authors: Valle-Melón J. M. , Rodríguez-Miranda Á. , Pérez-Vidiella P.
Published: March 2011

As in other engineering structures, historic buildings are conditioned by atmospheric changes which affect their size and shape. These effects follow a more or less cyclic pattern and do not normally put the stability of such buildings in jeopardy since they are part of their natural dynamics. Nevertheless, the study of these effects provides valuable information to understand the behavior of both the building and the materials it is made of.
This paper arose from the project of geometric monitoring of a presumably unstable historic building: the church of Santa María la Blanca in Agoncillo (La Rioja, Spain), which is being observed with conventional surveying equipment. The computations of the different epochs show several movements that can be explained as due to seasonal cycles.
La fiction à substrat professionnel : une autre voie d’accès à l’anglais de spécialité
Authors: Petit Michel
Published: March 2011

Cette étude se propose de démontrer l’existence d’un genre littéraire spécifique regroupant plusieurs variétés de fiction commerciale telles que le thriller médical, le thriller juridique, le thriller militaire. L’appellation de fiction à substrat professionnel (FASP) qui lui est donnée ici sera justifiée par l’analyse de ses principales caractéristiques externes et internes. On suggérera en outre que la nature de la FASP en fait un objet pertinent pour l’anglistique de spécialité.
Diagnosis of metastatic fibrolamellar hepatocellular carcinoma by endoscopic ultrasound-guided fine needle aspiration
Authors: Crowe Amanda , Knight Carrie S. , Jhala Darshana , Bynon Steve J. , Jhala Nirag C.
Published: March 2011

The fibrolamellar variant of hepatocellular carcinoma (FL-HCC) is distinguished from other hepatocellular carcinomas (HCC) by its unique clinical and pathologic features. Cytological features for this tumor on fine needle aspiration (FNA) of primary tumors have been described earlier. We present here a unique case of metastatic FL-HCC diagnosed by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of mediastinal adenopathy. A 32-year-old woman with a history of oral contraceptive use presented with nausea and severe abdominal pain but no ascites or stigmata of cirrhosis. She had a past history of resection of a liver lesion. Serial computed tomography scans revealed mediastinal lymphadenopathy and the patient was referred for endoscopic ultrasound (EUS). A transesophageal EUS-FNA was performed and tissue was collected for cytological evaluation by an on-site pathologist with no knowledge of prior history. Based on morphology correlated with prior history received later, a final diagnosis of metastatic FL-HCC in the retrocardiac lymph node was rendered on the EUS-FNA samples. There are very few reports in the literature where a diagnosis of FL-HCC is rendered at unusual sites. This case highlights that EUS-FNA is a relatively non-invasive, rapid, accurate and effective modality in obtaining tissue from otherwise hard-to-reach areas. It also suggests that metastasis of FL-HCC can be observed in mediastinal nodes and that diagnosis based on cytological features can be rendered even when the tumor is identified at unusual locations.
Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman Disease): A case report and review of 49 cases with fine needle aspiration cytology
Authors: Shi Yuquan , Griffin Adrienne Carruth , Zhang Paul JL , Palmer James N , Gupta Prabodh
Published: March 2011

Rosai–Dorfman disease (RDD), a rare, benign, self-limiting histiocytic proliferative disorder, can be encountered in both nodal and extranodal locations, and fine needle aspiration (FNA), a simple, accurate and economic tool, has been widely used for the diagnosis of superficial and deep-seated lesions. Familiarity with the cytomorphologic features of RDD is important as prognosis and treatment are quite different from other benign or malignant diseases for which it may clinically masquerade. Although large numbers of RDD cases have been reported, review of the literature has revealed 49 reported cases of RDD diagnosed by FNA. Here, we report a case of RDD with nasal and sinus involvement. The patient was seen at our institution, carrying a diagnosis of inflammatory pseudotumor rendered by an outside institution, based on material obtained by nasal and sinus surgical biopsies. Cervical lymph node FNA performed at our institution revealed typical features of RDD. The case, as well as a brief review of the literature and 49 RDD cases with FNA cytology, will be discussed.
Dependence of aerosol-precipitation interactions on humidity in a multiple-cloud system
Authors: Lee S. S.
Published: March 2011

Abstract. This study examines the dependence of aerosol-precipitation interactions on environmental humidity in a mesoscale cloud ensemble (MCE) which is composed of convective and stratiform clouds. The author found that increases in aerosol concentration enhance evaporative cooling, which raises not only the intensity of vorticity and entrainment but also that of downdrafts and low-level convergence. The increase in vorticity tends to suppress precipitation. The increase in low-level convergence tends to enhance precipitation by generating more secondary clouds in a muptiple-cloud system simulated here. At high humidity, the effect of the increased vorticity on cloud-liquid mass and, thus, precipitation is outweighed by that of the increased low-level convergence. This leads to the precipitation enhancement induced by the increase in aerosol concentration. When humidity lowers to mid humidity, the effect of aerosol on low-level convergence still dominates that on entrainment, leading to the precipitation enhancement with the increased aerosol concentration. With the lowest humidity in the current work, the effect of aerosol on entrainment dominates that on low-level convergence, leading to the precipitation suppression with the increased aerosol concentration. Hence, there is not only a competition between the effect of evaporation on vorticity and that on low-level convergence at a given humidity level but also the variation of the competition with the varying humidity. This competition and variation are absent in a single-cloud system where the effect of low-level convergence on secondary clouds is absent. This exemplifies a difference in the mechanism which controls aerosol-precipitation interactions between a single-cloud system and a multiple-cloud system.
Summer and winter variations of dicarboxylic acids, fatty acids and benzoic acid in PM2.5 in Pearl Delta River Region, China
Authors: Ho K. F. , Ho S. S. H. , Lee S. C. , Kawamura K. , Zou S. C. , Cao J. J. , Xu H. M.
Published: March 2011

Abstract. Ground-based PM2.5 samples collected at four different sites in Pearl River Delta region (PRD) during winter and summer (from 14 December 2006 to 28 January 2007 in winter and from 4 July to 9 August 2007 in summer) were analyzed for 30 water-soluble organic species, including dicarboxylic acids, ketocarboxylic acids and dicarbonyls, nine fatty acids, and benzoic acid. Molecular distributions of dicarboxylic acids demonstrated that oxalic acid (C2) was the most abundant species followed by phthalic acid (Ph) in PRD region. The concentrations of total dicarboxylic acids ranged from 99 to 1340 ng m−3, with an average of 438 ± 267 ng m−3 in PRD. The concentrations of total ketocarboxylic acids ranged from 0.6 to 207 ng m−3 (43 ± 48 ng m−3 on average) while the concentrations of total α-dicarbonyls, including glyoxal and methylglyoxal, ranged from 0.2 to 89 ng m−3, with an average of 11 ± 18 ng m−3 in PRD. The total quantified water-soluble compounds (TQWOC) (organic carbon) accounted for 3.4 ± 2.2% of OC and 14.3 ± 10.3% of water-soluble OC (WSOC). Hexadecanoic acid (C16:0), octadecanoic acid (C18:0) and oleic acid (C18:1) were the three most abundant fatty acids in PRD. The distributions of fatty acids were characterized by a strong even carbon number predominance with a maximum (Cmax) at hexadecanoic acid (C16:0). Ratio of C18:1 to C18:0 acts as an indicator for aerosol aging. In PRD, an average of C18:1/C18:0 ratio was 0.53 ± 0.39, suggesting an enhanced photochemical degradation of unsaturated fatty acid. Moreover, the concentrations of benzoic acid ranged from 84 to 306 ng m−3, (165 ± 48 ng m−3 on average), which can be emitted as primary pollutant from motor vehicles exhaust, or formed from photochemical degradation of aromatic hydrocarbons. Seasonal variations of the organic specie concentrations were found in the four sampling cities. Higher concentrations of TQWOC were observed in winter (598 ± 321 ng m−3) than in summer (372 ± 215 ng m−3). However, the abundances of TQWOC in OC mass were higher in summer (0.9–12.4%, 4.5 ± 2.7% on average) than in winter (1.1–5.7, 2.5 ± 1.2% on average), being consistent with enhanced secondary production of dicarboxylic acids in warmer weather. Spatial variations of water-soluble dicarboxylic acids were characterized by higher concentrations in Hong Kong and lower concentrations in Guangzhou (GZ)/Zhaoqing (ZQ) during winter whereas the highest concentrations were observed in GZ/ZQ during summer. These spatial and seasonal distributions are consistent with photochemical production and the subsequent accumulation under different meteorological conditions.
Volcanic ash from Iceland over Munich: mass concentration retrieved from ground-based remote sensing measurements
Authors: Gasteiger J. , Groß S. , Freudenthaler V. , Wiegner M.
Published: March 2011

Abstract. Volcanic ash plumes, emitted by the Eyjafjallajökull volcano (Iceland) in spring 2010, were observed by the lidar systems MULIS and POLIS in Maisach (near Munich, Germany), and by a CIMEL Sun photometer and a JenOptik ceilometer in Munich. We retrieve mass concentrations of volcanic ash from the lidar measurements; spectral optical properties, i.e. extinction coefficients, backscatter coefficients, and linear depolarization ratios, are used as input for an inversion. The inversion algorithm searches for model aerosol ensembles with optical properties that agree with the measured values within their uncertainty ranges. The non-sphericity of ash particles is considered by assuming spheroids. Optical particle properties are calculated using the T-matrix method supplemented by the geometric optics approach. The lidar inversion is applied to observations of the pure volcanic ash plume in the morning of 17 April 2010. We find 1.45 g m−2 for the ratio between the mass concentration and the extinction coefficient at λ = 532 nm, assuming an ash density of 2.6 g cm−3. The uncertainty range for this ratio is from 0.87 g m−2 to 2.32 g m−2. At the peak of the ash concentration over Maisach the extinction coefficient at λ = 532 nm was 0.75 km−1 (1-h-average), which corresponds to a maximum mass concentration of 1.1 mg m−3 (0.65 to 1.8 mg m−3). Model calculations show that particle backscatter at our lidar wavelengths (λ ≤ 1064 nm), and thus the lidar retrieval, is hardly sensitive to large particles (r ≳ 3 μm); large particles, however, may contain significant amounts of mass. Therefore, as an independent cross check of the lidar retrieval and to investigate the presence of large particles in more detail, we model ratios of sky radiances in the aureole of the Sun and compare them to measurements of the CIMEL. These ratios are sensitive to particles up to r ≈ 10 μm. This approach confirms the mass concentrations from the lidar retrieval. We conclude that synergistic utilization of high quality lidar and Sun photometer data, in combination with realistic aerosol models, is recommended for improving ash mass concentration retrievals.
The fate of Saharan dust across the Atlantic and implications for a Central American dust barrier
Authors: Nowottnick E. , Colarco P. , da Silva A. , Hlavka D. , McGill M.
Published: March 2011

Abstract. Saharan dust was observed over the Caribbean basin during the summer 2007 NASA Tropical Composition, Cloud, and Climate Coupling (TC4) field experiment. Airborne Cloud Physics Lidar (CPL) and satellite observations from MODIS suggest a barrier to dust transport across Central America into the eastern Pacific. We use the NASA GEOS-5 atmospheric transport model with online aerosol tracers to perform simulations of the TC4 time period in order to understand the nature of this barrier. Our simulations are driven by the Modern Era Retrospective-Analysis for Research and Applications (MERRA) meteorological analyses. We evaluate our baseline simulated dust distributions using MODIS and CALIOP satellite and ground-based AERONET sun photometer observations. GEOS-5 reproduces the observed location, magnitude, and timing of major dust events, but our baseline simulation does not develop as strong a barrier to dust transport across Central America as observations suggest. Analysis of the dust transport dynamics and lost processes suggest that while both mechanisms play a role in defining the dust transport barrier, loss processes by wet removal of dust are about twice as important as transport. Sensitivity analyses with our model showed that the dust barrier would not exist without convective scavenging over the Caribbean. The best agreement between our model and the observations was obtained when dust wet removal was parameterized to be more aggressive, treating the dust as we do hydrophilic aerosols.
Simulating deep convection with a shallow convection scheme
Authors: Hohenegger C. , Bretherton C. S.
Published: March 2011

Abstract. Convective processes profoundly affect the global water and energy balance of our planet but remain a challenge for global climate modeling. Here we develop and investigate the suitability of a unified convection scheme, capable of handling both shallow and deep convection, to simulate cases of tropical oceanic convection, mid-latitude continental convection, and maritime shallow convection. To that aim, we employ large-eddy simulations (LES) as a benchmark to test and refine a unified convection scheme implemented in the Single-Column Community Atmosphere Model (SCAM). Our approach is motivated by previous cloud-resolving modeling studies, which have documented the gradual transition between shallow and deep convection and its possible importance for the simulated precipitation diurnal cycle. Analysis of the LES reveals that differences between shallow and deep convection, regarding cloud-base properties as well as entrainment/detrainment rates, can be related to the evaporation of precipitation. Parameterizing such effects and accordingly modifying the University of Washington shallow convection scheme, it is found that the new unified scheme can represent both shallow and deep convection as well as tropical and continental convection. Compared to the default SCAM version, the new scheme especially improves relative humidity, cloud cover and mass flux profiles. The new unified scheme also removes the well-known too early onset and peak of convective precipitation over mid-latitude continental areas.
Characterization of a thermal decomposition chemical ionization mass spectrometer for the measurement of peroxy acyl nitrates (PANs) in the atmosphere
Authors: Zheng W. , Flocke F. M. , Tyndall G. S. , Swanson A. , Orlando J. J. , Roberts J. M. , Huey L. G. , Tanner D. J.
Published: March 2011

Abstract. This paper presents a detailed laboratory characterization of a thermal dissociation ionization mass spectrometer (TD-CIMS) for the atmospheric measurement of Peroxyacetyl nitrate (PAN) and its homologues. PANs are efficiently dissociated in a heated inlet tube and the resulting peroxy acyl radicals are reacted with I– ions in a flow tube. The CIMS detects the corresponding carboxylate ions to give a specific and quantitative measurement of each PAN species. PAN, peroxypropionyl nitrate (PPN), peroxyisobutyryl nitrate (PiBN), peroxy-n-butyryl nitrate (PnBN), peroxyacryloyl nitrate (APAN), peroxycrotonyl nitrates (CPAN) and peroxymethacryloyl nitrate (MPAN) were cross-calibrated with both a dual channel GC/ECD and a total odd-nitrogen (NOy) instrument for the NCAR TD-CIMS' typical aircraft operation conditions. In addition, the instrument sensitivity to a number of more exotic PAN homologues (peroxyhydroxyacetyl nitrate, methoxyformyl peroxynitrate, and peroxybenzoyl nitrate) was evaluated qualitatively by comparisons with a long-path FTIR instrument. The sensitivity for PPN is slightly higher than that of PAN. Larger aliphatic and olefinic PAN compounds generally showed lower sensitivities. These differences are owing to secondary reactions in the thermal decomposition region, which either reduce the yield of peroxy acyl radicals or cause losses of these radicals through intramolecular decomposition. The relative importance of these secondary reactions varies considerably between different PAN species. Results also indicate that the reaction of the peroxy acyl radicals with the ion-water cluster, I–(H2O)n proceeds about an order of magnitude faster than with I– alone. Variations among the individual PAN species at very low water vapor were observed. The results call for careful evaluation of each PAN species to be measured and for each desired operating condition of a TD-CIMS instrument.
Simulating the oxygen content of ambient organic aerosol with the 2D volatility basis set
Authors: Murphy B. N. , Donahue N. M. , Fountoukis C. , Pandis S. N.
Published: March 2011

Abstract. A module predicting the oxidation state of organic aerosol (OA) has been developed using the two-dimensional volatility basis set (2D-VBS) framework. This model is an extension of the 1D-VBS framework and tracks saturation concentration and oxygen content of organic species during their atmospheric lifetime. The host model, a one-dimensional Lagrangian transport model, is used to simulate air parcels arriving at Finokalia, Greece during the Finokalia Aerosol Measurement Experiment in May 2008 (FAME-08). Extensive observations were collected during this campaign using an aerosol mass spectrometer (AMS) and a thermodenuder to determine the chemical composition and volatility, respectively, of the ambient OA. Although there are several uncertain model parameters, the consistently high oxygen content of OA measured during FAME-08 (O:C = 0.8) can help constrain these parameters and elucidate OA formation and aging processes that are necessary for achieving the high degree of oxygenation observed. The base-case model reproduces observed OA mass concentrations (measured mean = 3.1 μg m−3, predicted mean = 3.3 μg m−3) and O:C ratio (predicted O:C = 0.78) accurately. A suite of sensitivity studies explore uncertainties due to (1) the anthropogenic secondary OA (SOA) aging rate constant, (2) assumed enthalpies of vaporization, (3) the volatility change and number of oxygen atoms added for each generation of aging, (4) heterogeneous chemistry, (5) the oxidation state of the first generation of compounds formed from SOA precursor oxidation, and (6) biogenic SOA aging. Perturbations in most of these parameters do impact the ability of the model to predict O:C ratios well throughout the simulation period. By comparing measurements of the O:C ratio from FAME-08, several sensitivity cases including a high oxygenation case, low oxygenation case, and biogenic SOA aging case are found to unreasonably depict OA aging. However, many of the cases chosen for this study predict average O:C ratios that are consistent with the observations, illustrating the need for more thorough experimental characterizations of OA parameters including the enthalpy of vaporization and oxidation state of the first generation of SOA products. The ability of the model to predict OA concentrations is less sensitive to perturbations in the model parameters than its ability to predict O:C ratios. In this sense, quantifying the O:C ratio with a predictive model and constraining it with AMS measurements can reduce uncertainty in our understanding of OA formation and aging.
Calibration of atmospheric hydrogen measurements
Authors: Jordan A. , Steinberg B.
Published: March 2011

Abstract. Interest in atmospheric hydrogen (H2) has been growing in recent years with the prospect of H2 being a potential alternative to fossil fuels as an energy carrier. This has intensified research for a quantitative understanding of the atmospheric hydrogen cycle and its total budget, including the expansion of the global atmospheric measurement network. However, inconsistencies in published observational data constitute a major limitation in exploring such data sets. The discrepancies can be mainly attributed to difficulties in the calibration of the measurements. In this study various factors that may interfere with accurate quantification of atmospheric H2 were investigated including drifts of standard gases in high pressure cylinders. As an experimental basis a procedure to generate precise mixtures of H2 within the atmospheric concentration range was established. Application of this method has enabled a thorough linearity characterization of the commonly used GC-HgO reduction detector. We discovered that the detector response was sensitive to the composition of the matrix gas. Addressing these systematic errors, a new calibration scale has been generated defined by thirteen standards with dry air mole fractions ranging from 139–1226 nmol mol−1. This new scale has been accepted as the official World Meteorological Organisation's (WMO) Global Atmospheric Watch (GAW) H2 mole fraction scale.
Comparison of HDO measurements from Envisat/MIPAS with observations by Odin/SMR and SCISAT/ACE-FTS
Authors: Lossow S. , Steinwagner J. , Urban J. , Dupuy E. , Boone C. D. , Kellmann S. , Linden A. , Kiefer M. , Grabowski U. , Höpfner M. , Glatthor N. , Röckmann T. , Murtagh D. P. , Walker K. A. , Bernath P. F. , von Clarmann T. , Stiller G. P.
Published: March 2011

Abstract. Measurements of thermal emission in the mid-infrared by Envisat/MIPAS allow the retrieval of HDO information roughly in the altitude range between 10 km and 50 km. From September 2002 to March 2004 MIPAS performed measurements in the full spectral mode. To assess the quality of the HDO data set obtained during that period comparisons with measurements by Odin/SMR and SCISAT/ACE-FTS were performed. Comparisons were made on profile-to-profile basis as well as using seasonal and monthly means. All in all the comparisons yield favourable results. The largest deviations between MIPAS and ACE-FTS are observed below 15 km, where relative deviations can occasionally exceed 100%. Despite that the latitudinal structures observed by both instruments fit. Between 15 km and 20 km there is less consistency, especially in the Antarctic during winter and spring. Above 20 km there is a high consistency in the structures observed by all three instruments. MIPAS and ACE-FTS typically agree within 10%, with MIPAS mostly showing higher abundances than ACE-FTS. Both data sets show considerably more HDO than SMR. This bias can mostly be explained by uncertainties in spectroscopic parameters. Above 40 km, where the MIPAS HDO retrieval reaches its limits, still good agreement with the structures observed by SMR is found for most seasons. This puts some confidence in the MIPAS data at these altitudes.
Simulation of polar stratospheric clouds in the chemistry-climate-model EMAC via the submodel PSC
Authors: Kirner O. , Ruhnke R. , Buchholz-Dietsch J. , Jöckel P. , Brühl C. , Steil B.
Published: March 2011

Abstract. The submodel PSC of the ECHAM5/MESSy Atmospheric Chemistry model (EMAC) has been developed to simulate the main types of polar stratospheric clouds (PSC). The parameterisation of the supercooled ternary solutions (STS, type 1b PSC) in the submodel is based on Carslaw et al. (1995b), the thermodynamic approach to simulate ice particles (type 2 PSC) on Marti and Mauersberger (1993). For the formation of nitric acid trihydrate (NAT) particles (type 1a PSC) two different parameterisations exist. The first is based on an instantaneous thermodynamic approach from Hanson and Mauersberger (1988), the second is new implemented and considers the growth of the NAT particles with the aid of a surface growth factor based on Carslaw et al. (2002). It is possible to choose one of this NAT parameterisation in the submodel. This publication explains the background of the submodel PSC and the use of the submodel with the goal of simulating realistic PSC in EMAC.
Generalized versus non-generalized neural network model for multi-lead inflow forecasting at Aswan High Dam
Authors: El-Shafie A. , Noureldin A.
Published: March 2011

Abstract. Artificial neural networks (ANN) have been found efficient, particularly in problems where characteristics of the processes are stochastic and difficult to describe using explicit mathematical models. However, time series prediction based on ANN algorithms is fundamentally difficult and faces problems. One of the major shortcomings is the search for the optimal input pattern in order to enhance the forecasting capabilities for the output. The second challenge is the over-fitting problem during the training procedure and this occurs when ANN loses its generalization. In this research, autocorrelation and cross correlation analyses are suggested as a method for searching the optimal input pattern. On the other hand, two generalized methods namely, Regularized Neural Network (RNN) and Ensemble Neural Network (ENN) models are developed to overcome the drawbacks of classical ANN models. Using Generalized Neural Network (GNN) helped avoid over-fitting of training data which was observed as a limitation of classical ANN models. Real inflow data collected over the last 130 years at Lake Nasser was used to train, test and validate the proposed model. Results show that the proposed GNN model outperforms non-generalized neural network and conventional auto-regressive models and it could provide accurate inflow forecasting.
Series distance – an intuitive metric to quantify hydrograph similarity in terms of occurrence, amplitude and timing of hydrological events
Authors: Ehret U. , Zehe E.
Published: March 2011

Abstract. Applying metrics to quantify the similarity or dissimilarity of hydrographs is a central task in hydrological modelling, used both in model calibration and the evaluation of simulations or forecasts. Motivated by the shortcomings of standard objective metrics such as the Root Mean Square Error (RMSE) or the Mean Absolute Peak Time Error (MAPTE) and the advantages of visual inspection as a powerful tool for simultaneous, case-specific and multi-criteria (yet subjective) evaluation, we propose a new objective metric termed Series Distance, which is in close accordance with visual evaluation. The Series Distance quantifies the similarity of two hydrographs neither in a time-aggregated nor in a point-by-point manner, but on the scale of hydrological events. It consists of three parts, namely a Threat Score which evaluates overall agreement of event occurrence, and the overall distance of matching observed and simulated events with respect to amplitude and timing. The novelty of the latter two is the way in which matching point pairs on the observed and simulated hydrographs are identified: not by equality in time (as is the case with the RMSE), but by the same relative position in matching segments (rise or recession) of the event, indicating the same underlying hydrological process. Thus, amplitude and timing errors are calculated simultaneously but separately, from point pairs that also match visually, considering complete events rather than only individual points (as is the case with MAPTE). Relative weights can freely be assigned to each component of the Series Distance, which allows (subjective) customization of the metric to various fields of application, but in a traceable way. Each of the three components of the Series Distance can be used in an aggregated or non-aggregated way, which makes the Series Distance a suitable tool for differentiated, process-based model diagnostics. After discussing the applicability of established time series metrics for hydrographs, we present the Series Distance theory, discuss its properties and compare it to those of standard metrics used in Hydrology, both at the example of simple, artificial hydrographs and an ensemble of realistic forecasts. The results suggest that the Series Distance quantifies the degree of similarity of two hydrographs in a way comparable to visual inspection, but in an objective, reproducible way.
Simplifying a hydrological ensemble prediction system with a backward greedy selection of members – Part 1: Optimization criteria
Authors: Brochero D. , Anctil F. , Gagné C.
Published: March 2011

Abstract. Hydrological Ensemble Prediction System (HEPS), obtained by forcing rainfall-runoff models with Meteorological Ensemble Prediction Systems (MEPS), have been recognized as useful approaches to quantify uncertainties of hydrological forecasting systems. This task is complex both in terms of the coupling of information and computational time, which may create an operational barrier. The main objective of the current work is to assess the degree of simplification (reduction of members) of a HEPS configured with 16 lumped hydrological models driven by the 50 weather ensemble forecasts from the European Center for Medium-range Weather Forecasts (ECMWF). Here, the selection of the most relevant members is proposed using a Backward greedy technique with k-fold cross-validation, allowing an optimal use of the information. The methodology draws from a multi-criterion score that represents the combination of resolution, reliability, consistency, and diversity. Results show that the degree of reduction of members can be established in terms of maximum number of members required (complexity of the HEPS) or the maximization of the relationship between the different scores (performance).
Simplifying a hydrological ensemble prediction system with a backward greedy selection of members – Part 2: Generalization in time and space
Authors: Brochero D. , Anctil F. , Gagné C.
Published: March 2011

Abstract. An uncertainty cascade model applied to stream flow forecasting seeks to evaluate the different sources of uncertainty of the complex rainfall-runoff process. The current trend focuses on the combination of Meteorological Ensemble Prediction Systems (MEPS) and hydrological model(s). However, the number of members of such a HEPS may rapidly increase to a level that may not be operationally sustainable. This article evaluates a 94% simplification of an initial 800-member HEPS, forcing 16 lumped rainfall-runoff models with the European Center for Medium-range Weather Forecasts (ECMWF MEPS). More specifically, it tests the time (local) and space (regional) generalization ability of the simplified 50-member HEPS obtained using a methodology that combines 4 main aspects: (i) optimizing information of the short-length series using k-folds cross-validation, (ii) implementing a backward greedy selection technique, (iii) guiding the selection with a linear combination of diversified scores, and (iv) formulating combination case studies at the cross-validation stage. At the local level, the transferability of the 9th day member selection was proven for the other 8 forecast horizons at an 82% success rate. At the regional level, a good performance was also achieved when the 50-member HEPS was applied to a neighbouring catchment within the same cluster. Diversity, defined as hydrological model complementarities addressing different aspects of a forecast, was identified as the critical factor for proper selection applications.
Modelling the temperature evolution of permafrost and seasonal frost in southern Norway during the 20th and 21st century
Authors: Hipp T. , Etzelmüller B. , Farbrot H. , Schuler T. V.
Published: March 2011

Abstract. A heat flow model was used to simulate both past and future ground temperatures of mountain permafrost in Southern Norway. A reconstructed air temperature series back to 1860 was used to evaluate the permafrost evolution since the end of the Little Ice Age in the region. The impact of a changing climate on discontinuous mountain permafrost until 2100 is predicted by using downscaled temperatures from an ensemble of downscaled climate models for the A1B scenario. From 13 borehole locations two consecutive years of ground temperature, air temperature and snow cover data are available for model calibration and validation. The boreholes are located at different elevations and in substrates having different thermal properties. With an increase of air temperature of ~+1.5 °C over 1860–2010 and an additional warming of +2.8 °C towards 2100 in air temperature, we simulate the evolution of ground temperatures for the borehole locations. According to model results, the active-layer thickness has increased since 1860 by about 0.5–5 m and >10 m for the sites Juvvass and Tron, respectively. The simulations also suggest that at an elevation of about 1900 m a.s.l. permafrost will degrade until the end of this century with a likelihood of 55–75% given the chosen A1B scenario.
New Biological Solutions for Hemodialysis Access
Authors: Peck Marissa K. , Dusserre Nathalie , Zagalski Krzysztof , Garrido Sergio A. , Wystrychowski Wojciech , Glickman Marc H. , Chronos Nicolas A.F. , Cierpka Lech , L'Heureux Nicolas , McAllister Todd N.
Published: March 2011

Since Scribner described the first prosthetic chronic dialysis shunt in 1961, the surgical techniques and strategies to maintain vascular access have improved dramatically. Today, hundreds of thousands of patients worldwide are treated with some combination of native vein fistula, synthetic vascular graft, or synthetic semipermanent catheter. Despite significantly lower efficacy compared with autologous fistulae, the basic materials used for synthetic shunts and catheters have evolved surprisingly slowly. The disparity between efficacy rates and concomitant maintenance costs has driven a strong campaign to decrease the use of synthetic grafts and catheters in favor of native fistulae. Whether arguing the benefits of Fistula First or “Catheter Last,” the fact that clinicians are in need of an alternative to expanded polytetrafluoroethylene (ePTFE) is irrefutable. The poor performance of synthetic materials has a significant economic impact as well. End-stage renal disease (ESRD) accounts for approximately 6% of Medicare's overall budget, despite a prevalence of about 0.17%. Of that, 15%–25% is spent on access maintenance, making hemodialysis access a critical priority for Medicare. This clinical and economic situation has spawned an aggressive effort to improve clinical care strategies to reduce overall cost and complications. While the bulk of this effort has historically focused on developing new synthetic biomaterials, more recently, investigators have developed a variety of cell-based strategies to create tissue-engineered vascular grafts. In this article, we review the evolution of the field of cardiovascular tissue engineering. We also present an update on the Lifeline™ vascular graft, an autologous, biological, and tissue-engineered vascular graft, which was the first tissue-engineered graft to be used clinically in dialysis patients.
Preparation of C5‐Functionalized Locked Nucleic Acids (LNAs)
Authors: Kumar Pawan , Østergaard Michael E. , Hrdlicka Patrick J.
Published: March 2011

Relative to conventional locked nucleic acids (LNAs), C5‐functionalized LNAs with small entities at the C5‐position display markedly higher (1) duplex thermostability with complementary single‐stranded DNA/RNA targets, (2) target specificity, and (3) 3′‐exonuclease stability. C5‐Functionalized LNAs carrying a polarity‐sensitive fluorophore enable sensitive and efficient discrimination of single nucleotide polymorphisms (SNPs) under non‐stringent conditions. This unit describes protocols for chemical synthesis of an LNA uridine diol and corresponding C5‐functionalized LNA uridine phosphoramidites. A procedure for incorporation of C5‐functionalized LNA uridine phosphoramidites into oligodeoxyribonucleotides by automated DNA synthesis is also described. Curr. Protoc. Nucleic Acid Chem. 44:4.43.1‐4.43.22. © 2011 by John Wiley & Sons, Inc.