bluuebunny/crossref_metadata_2025 huggingface dataset:
Subdural Hematomas in Pulmonary Arterial Hypertension Patients Treated with Protacyclin Analogs
Authors: Louis Lam , Bair Nancy , Banjac Svetlana , Dweik Raed A. , Tonelli Adriano R.
Published: December 2012

Prostacyclin analogs therapy has been associated with development of thrombocytopenia. Little is known whether this treatment increases the risk of intracranial hemorrhage in pulmonary artery hypertension (PAH) patients. We queried the Cleveland Clinic billing database to identify cases of nontraumatic sudural hematoma (SDH) in patients with PAH. We identified those individuals who were receiving prostacyclin analogs therapy at the time of the neurological event and assessed whether these patients were also taking antiplatelet or anticoagulation therapies. We identified three cases of nontraumatic SDH in 856‐patient‐year of prostacylin analog treatment. All patients were women, had low normal platelet counts or thrombocytopenia, and were concomitantly receiving anticoagulation therapy in the appropriate therapeutic anticoagulation range. All three patients were managed conservatively and had no neurologic sequelae. Nontraumatic acute subdural hematoma is a rare event in patients with PAH treated with prostacyclin analogs. All affected patients were concomitantly receiving anticoagulation therapy.
Towards Active SEO (Search Engine Optimization) 2.0
Authors: Boutet Charles-Victor , Quoniam Luc
Published: December 2012

In the age of writable web, new skills and new practices are appearing. In an environment that allows everyone to communicate information globally, internet referencing (or SEO) is a strategic discipline that aims to generate visibility, internet traffic and a maximum exploitation of sites publications. Often misperceived as a fraud, SEO has evolved to be a facilitating tool for anyone who wishes to reference their website with search engines. In this article we show that it is possible to achieve the first rank in search results of keywords that are very competitive. We show methods that are quick, sustainable and legal; while applying the principles of active SEO 2.0. This article also clarifies some working functions of search engines, some advanced referencing techniques (that are completely ethical and legal) and we lay the foundations for an in depth reflection on the qualities and advantages of these techniques.
Determinants of the Choice of Marketing Channels by Corporate Clients: an Analysis of the Information Technology Sector
Authors: Soares Guilherme , Bortoluzzo Adriana Bruscato , Barros Henrique Machado
Published: December 2012

Based on a survey of 505 corporate clients from the information technology industry, this study uses a logit statistical model to analyze whether such factors as loyalty, trust, client importance, intimacy between customer and supplier and the cost of changing suppliers may affect the choice of the marketing channel used by the client. The results show that the greater intimacy between a supplier and a corporate client is a determining factor for the client’s preference for being served by the manufacturer rather than an intermediary. In contrast, clients’ perception of their own importance to the supplier is not very relevant to their preference for being served directly by the manufacturer, and the other factors were not identified as (statistically important) determinants of the choice of the marketing channel. These results suggest that the real advantage of the direct sales channel over the indirect sales channel lies in its ability to strengthen the client-manufacturer relationship, thereby contributing to the development of solutions that better serve the needs of corporate clients.
Uncommon and Atypical Sinonasal Masses: Diagnostic and Therapeutic Challenges
Authors: Sharma Vinit Kumar , Sharma Rohit , Madhok Rajneesh , Agarwal Tanu , Mehrotra Ashish , Kochhar Anisha
Published: December 2012

Introduction

Sinonasal masses are a wide range of pathologies ranging from simple nasal polyps to rare tumors like esthesioneuroblastomas. Early symptoms of all of them are similar to common nasal and sinus problems, hence, producing a delay in diagnosis.

Materials and methods

All the patients presenting with sinonasal masses in the Department of ENT and Head/Neck Surgery, SRMS Institute of Medical Sciences, Bareilly, were included in the study. The study was carried out between January 2007 and December 2011. Detailed history and ENT examination were recorded. Radiological investigation was carried out in the form of computed tomographic (CT) scan of nose and paranasal sinuses. Final diagnosis was made by histopathological examination either before instituting any form of treatment or by a postsurgical biopsy where surgery was carried out. Immunohistochemistry was done in some cases as deemed necessary by the pathologist. Thus, their modes of presentation, radiological and histopathological profiles were studied along with dilemmas in diagnosis and management.

Results

A total of 189 nasal masses were observed during this period. Out of which 126 were diagnosed as nasal polyps and were excluded from the study. Thus, 63 uncommon nasal masses were seen in the study period. A large number of uncommon sinonasal masses had atypical presentation and/or presented in an advanced stage to pose a diagnostic and surgical challenge. Endoscopic techniques are becoming a gold standard in surgical resection in most of them. Interdepartmental cooperation is highly essential.

How to cite this article

Sharma R, Sharma VK, Madhok R, Agarwal T, Mehrotra A, Kochhar A. Uncommon and Atypical Sinonasal Masses: Diagnostic and Therapeutic Challenges. Clin Rhinol An Int J 2012;5(3):114-117.
Small-Cell Neuroendocrine Carcinoma of Nasopharynx
Authors: Shunyu N Brian , Lynrah Zaren , Raphal Vandana
Published: December 2012

Small-cell neuroendocrine carcinoma occurring in nasopharynx are extremely rare. Only three cases of small-cell neuroendocrine carcinoma occurring in nasopharynx have been reported uptodate. To our knowledge this is the fourth case of small-cell neuroendocrine carcinoma of the nasopharynx reported in world literature. We present this case for its rarity.

How to cite this article

Shunyu NB, Lynrah Z, Goyal A, Raphal V. Small-Cell Neuroendocrine Carcinoma of Nasopharynx. Clin Rhinol An Int J 2012;5(3):130-131.
Melanotic Neuroectodermal Tumor of Infancy
Authors: Tripuraneni Satish Chandra
Published: December 2012

Melanotic neuroectodermal tumor of infancy (MNTI) is a relatively uncommon osteolytic-pigmented neoplasm that primarily affects the jaws of newborn infants. Here, we are reporting a case of MNTI presented at the age of 12 years. The objective of this report is to review the incidence, presentation, investigation protocols, management options and outcomes.

How to cite this article

Tripuraneni SC. Melanotic Neuroectodermal Tumor of Infancy. Clin Rhinol An Int J 2012;5(3):138-139.
A contribuição do PDI nas atividades de planejamento e gestão das instituições de educação superior
Authors: Francisco Thiago Henrique Almino , Nakayama Marina Keiko , Ramos Alexandre Moraes , Oliveira Paulo Cristiano
Published: December 2012

O artigo versa sobre os aspectos que confirmam a relevância do Plano de Desenvolvimento Institucional – PDI - na estruturação do planejamento e gestão das instituições de educação superior, apresentando aspectos que convalidam este fato nos diversos modelos institucionais vigentes na contemporaneidade nacional. A digressão teórica elenca aspectos relacionados às bases conceituais do planejamento universitário, a importância do Decreto 5773/06 na constituição do PDI, a contribuição dos documentos institucionais no processo de gestão e ao processo de planejamento nas instituições de educação superior, sob o lume do PDI como instrumento de destaque no cerne estratégico das instituições. Para tanto, as interações metodológicas ocorrem sob as bases da pesquisa acadêmica, de caráter documental indireto e que se classifica como sendo descritiva-explicativa, predominantemente qualitativa e designada como sendo uma pesquisa participante. As investigações construtivistas permitiram concluir, entre outros desígnios, que o Plano de Desenvolvimento Institucional é fator estruturante de uma gestão estratégica direcionada para a utilização de indicadores especificamente relacionados ao modelo institucional apregoado pela IES, além de contribuir na construção de um processo de avaliação institucional sistemático, formativo e determinante aos ensejos institucionais
Os cursos superiores de tecnologia e o mundo do trabalho
Authors: Reis Edson Andrade dos , Reis Everson Andrade dos
Published: December 2012

Com a crescente inovação tecnológica no âmbito das organizações, tornou-se clara a necessidade de uma estreita relação entre a instituição produtora do saber, conhecimento técnico e científico e as empresas. o objetivo principal deste trabalho é abordar as interações dos cursos superiores de tecnologias e as empresas, de forma a auxiliar as análises de um curso de tecnologia e sua inserção no junto do trabalho como forma a contribuir ao desenvolvimento da sociedade e o aumento do percentual da população com nível superior no país. no presente estudo. A coleta de dados foi realizada por meio do método de entrevistas com gestores das empresas das regiões de Brasília, Joinville e São Paulo utilizando-se um questionário semi-estruturado. A pesquisa foi aplicada entre os dias 20 de julho a 10 de setembro de 2012, onde foram coletados 51 questionários, sendo 24 questionários de gestores da cidade de Brasília, 18 questionários de gestores da cidade de Joinville e 9 questionários da cidade de São Paulo. Os cursos superiores de tecnologia não estão desenvolvendo as potencialidades do ensino superior profissionalizante na sua plenitude principalmente pela falta de interação das empresas no modelamento das matrizes curriculares.
Planejamento orçamentário: as práticas da Universidade Federal de Lavras
Authors: Silva Patrícia Maria , Carvalho Walter Weider de , Carvalho Fauze Alvarenga , Furtado Renata Pedretti Morais
Published: December 2012

O presente artigo traz uma abordagem sobre o planejamento orçamentário praticado na Universidade Federal de Lavras - UFLA. O planejamento é uma ferramenta de auxílio na gestão das instituições que devem possuir uma consciência de se planejar o presente e uma visão de futuro. As decisões e ações futuras, em qualquer tipo de atividade econômica ou de interesse público, devem ser planejadas. O planejamento das instituições públicas brasileiras tem por base o Plano Plurianual do Governo que deve ser executado para atingir o cumprimento das metas estabelecidas pelo governo federal. A UFLA tem seu orçamento baseado no modelo de alocação de recursos orçamentários definido pela Secretaria de Educação Superior (SESu) do MEC, em parceria com a ANDIFES. Na busca pela gestão eficiente dos recursos públicos, pelo aprimoramento da gestão por meio de práticas gerenciais e para maximizar o uso desses recursos, uma parcela do recurso da UFLA é gerida de forma descentralizada, por meio do que se convencionou a chamar “Matriz de Descentralização de Recursos da UFLA” (Matriz-UFLA). A partir da implementação da Matriz-UFLA, houve um avanço na gestão, especificamente na maneira de se planejar e controlar o gasto da OCC - Outros Custeio e Capital. Foi possível alocar recursos de maneira equitativa, reconhecendo a competência de cada departamento e evitando a luta por uma “fatia justa” de recursos.
O uso da gestão de projetos para a implantação de uma gestão da informação integrada e participativa: a experiência da coordenadoria de educação aberta e a distância da Universidade Federal de Viçosa-MG
Authors: Faria Leo Jaime Ribeiro , Barbosa Telma Regina da Costa Guimarães
Published: December 2012

A gerência da Educação a Distância exige que seus gestores executem tarefas de planejamento, sistematização, organização, direção e controle de processos e projetos e por isso não pode prescindir de um gerenciamento da informação que atenda aos requisitos de integração, de responsabilidade coletiva e de participação. Sendo assim, este trabalho teve como objetivo a implementação da gestão da informação na Coordenadoria de Educação Aberta e a Distância da Universidade Federal de Viçosa (CEAD-UFV), seguindo a metodologia de gerenciamento de projetos com base numa modificação dodotProject, um software livre de código aberto. Para tanto, foi desenvolvido e implementado um sistema de gerenciamento da informação na Coordenadoria, com base na metodologia da gestão de projetos para organizações de tecnologia da informação e comunicação. Constatou-se que o modelo implantado ofereceu à CEAD-UFV uma visão sistêmica de seus projetos e dinamizou o fluxo de informações. A experiência mostrou ainda que a gestão baseada nagerência de projetos permite enfatizar a sinergia entre grupos necessária no contexto de EaD.
Age of stratospheric air in the ERA-Interim
Authors: Diallo M. , Legras B. , Chédin A.
Published: December 2012

Abstract. The Brewer-Dobson mean circulation and its variability are investigated in the ERA-Interim over the period 1989-2010 by using an off-line Lagrangian transport model driven by analysed winds and heating rates. At low and mid-latitudes, the mean age of air in the lower stratosphere is in good agreement with ages derived from aircraft, high altitude balloon and satellite observations of long-lived tracers. At high latitude and in the upper stratosphere, we find, however that the ERA-Interim ages exhibit an old bias, typically of one to two years. The age spectrum exhibits a long tail except in the low tropical stratosphere which is modulated by the annual cycle of the tropical upwelling. The distribution of ages and its variability is consistent with the existence of two separate branches, shallow and deep, of the Brewer-Dobson circulation. Both branches are modulated by the tropical upwelling and the shallow branch is also modulated by the subtropical barrier. The variability of the mean age is analysed through a decomposition in terms of annual cycle, QBO, ENSO and trend. The annual modulation is the dominating signal in the lower stratosphere and is maximum at latitudes greater than 50° in both hemispheres with oldest ages at the end of the winter. The phase of the annual modulation is also reversed between below and above 25 km. The maximum amplitude of the QBO modulation is of about 0.5 yr and is mostly concentrated within the tropics between 25 and 35 km. It lags the QBO wind at 30 hPa by about 8 months. The ENSO signal is small and limited to the lower northen stratosphere. The age trend over the 1989–2010 period, according to this ERA-Interim dataset, is significant and negative, of the order of −0.3 to −0.5 yr dec−1, within the lower stratosphere in the Southern Hemisphere and south of 40° N in the Northern Hemisphere below 25 km. The age trend is positive (of the order of 0.3 yr dec−1) in the mid stratosphere but there is no region of consistent significance. This suggests that the shallow and deep Brewer-Dobson circulations may evolve in opposite directions. Finally, we find that the long lasting influence of the Pinatubo eruption can be seen on the age of air from June 1991 until the end of 1993 and can bias the statistics encompassing this period.
Quantifying the deep convective temperature signal within the tropical tropopause layer (TTL)
Authors: Paulik L. C. , Birner T.
Published: December 2012

Abstract. Dynamics on a vast range of spatial and temporal scales, from individual convective plumes to planetary-scale circulations, play a role in driving the temperature variability in the tropical tropopause layer (TTL). Here, we aim to better quantify the deep convective temperature signal within the TTL using multiple datasets. First, we investigate the link between ozone and temperature in the TTL using the Southern Hemisphere Additional Ozonesondes (SHADOZ) dataset. Low ozone concentrations in the TTL are indicative of deep convective transport from the boundary layer. We confirm the usefulness of ozone as an indicator of deep convection by identifying a typical temperature signal associated with reduced ozone events: an anomalously warm mid to upper troposphere and an anomalously cold upper TTL. We quantify these temperature signals using two diagnostics: (1) the "ozone minimum" diagnostic, which has been used in previous studies and identifies the upper tropospheric minimum ozone concentration as a proxy for the level of main convective outflow; and (2) the "ozone mixing height", which we introduce in order to identify the maximum altitude in a vertical ozone profile up to which reduced ozone concentrations, typical of transport from the boundary layer are observed. Results indicate that the ozone mixing height diagnostic better separates profiles with convective influence than the ozone minimum diagnostic. Next, we collocate deep convective clouds identified by CloudSat 2B-CLDCLASS with temperature profiles based on Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Global Position System (GPS) radio occultations. We find a robust large-scale deep convective TTL temperature signal, that is persistent in time. However, it is only the convective events that penetrate into the upper half of the TTL that have a significant impact on TTL temperature. A distinct seasonal difference in the spatial scale and the persistence of the temperature signal is identified. Deep-convective cloud top heights are on average found to be well described by the level of neutral buoyancy.
Trends in OMI NO2 observations over the United States: effects of emission control technology and the economic recession
Authors: Russell A. R. , Valin L. C. , Cohen R. C.
Published: December 2012

Abstract. Observations of tropospheric NO2 vertical column densities over the United States (US) for 2005–2011 are evaluated using the OMI Berkeley High Resolution (BEHR) retrieval algorithm. We assess changes in NO2 on day-of-week and interannual timescales to assess the impact of changes in emissions from mobile and non-mobile sources on the observed trends. We observe consistent decreases in cities across the US, with an average total reduction of 32 ± 7% across the 7 yr. Changes for large power plants have been more variable (−26 ± 12%) due to regionally-specific regulation policies. An increasing trend of 10–20% in background NO2 columns in the northwestern US is observed. We examine the impact of the economic recession on emissions and find that decreases in NO2 column densities over cities were moderate prior to the recession (−6 ± 5% yr−1), larger during the recession (−8 ± 5% yr−1), and then smaller after the recession (−3 ± 4% yr−1). Differences in the trends observed on weekdays and weekends indicate that prior to the economic recession, NO2 reductions were dominated by technological improvements to the light-duty vehicle fleet but that a decrease in diesel truck activity has contributed to emission reductions since the recession. We use the satellite observations to estimate a 34% decrease in NO2 from mobile sources in cities for 2005–2011 and use that value to infer changes in non-mobile sources. We find that reductions in NO2 from non-mobile sources in cities have been both more modest and more variable than NO2 reductions from mobile sources (−10 ± 13%).
Future impact of traffic emissions on atmospheric ozone and OH based on two scenarios
Authors: Hodnebrog Ø. , Berntsen T. K. , Dessens O. , Gauss M. , Grewe V. , Isaksen I. S. A. , Koffi B. , Myhre G. , Olivié D. , Prather M. J. , Stordal F. , Szopa S. , Tang Q. , van Velthoven P. , Williams J. E.
Published: December 2012

Abstract. The future impact of traffic emissions on atmospheric ozone and OH has been investigated separately for the three sectors AIRcraft, maritime SHIPping and ROAD traffic. To reduce uncertainties we present results from an ensemble of six different atmospheric chemistry models, each simulating the atmospheric chemical composition in a possible high emission scenario (A1B), and with emissions from each transport sector reduced by 5% to estimate sensitivities. Our results are compared with optimistic future emission scenarios (B1 and B1 ACARE), presented in a companion paper, and with the recent past (year 2000). Present-day activity indicates that anthropogenic emissions so far evolve closer to A1B than the B1 scenario. As a response to expected changes in emissions, AIR and SHIP will have increased impacts on atmospheric O3 and OH in the future while the impact of ROAD traffic will decrease substantially as a result of technological improvements. In 2050, maximum aircraft-induced O3 occurs near 80° N in the UTLS region and could reach 9 ppbv in the zonal mean during summer. Emissions from ship traffic have their largest O3 impact in the maritime boundary layer with a maximum of 6 ppbv over the North Atlantic Ocean during summer in 2050. The O3 impact of road traffic emissions in the lower troposphere peaks at 3 ppbv over the Arabian Peninsula, much lower than the impact in 2000. Radiative forcing (RF) calculations show that the net effect of AIR, SHIP and ROAD combined will change from a marginal cooling of −0.44 ± 13 mW m−2 in 2000 to a relatively strong cooling of −32 ± 9.3 (B1) or −32 ± 18 mW m−2 (A1B) in 2050, when taking into account RF due to changes in O3, CH4 and CH4-induced O3. This is caused both by the enhanced negative net RF from SHIP, which will change from −19 ± 5.3 mW m−2 in 2000 to −31 ± 4.8 (B1) or −40 ± 9 mW m−2 (A1B) in 2050, and from reduced O3 warming from ROAD, which is likely to turn from a positive net RF of 12 ± 8.5 mW m−2 in 2000 to a slightly negative net RF of −3.1 ± 2.2 (B1) or −3.1 ± 3.4 (A1B) mW m−2 in the middle of this century. The negative net RF from ROAD is temporary and induced by the strong decline in ROAD emissions prior to 2050, which only affects the methane cooling term due to the longer lifetime of CH4 compared to O3. The O3 RF from AIR in 2050 is strongly dependent on scenario and ranges from 19 ± 6.8 (B1 ACARE) to 61 ± 14 mW m−2 (A1B). There is also a considerable span in the net RF from AIR in 2050, ranging from −0.54 ± 4.6 (B1 ACARE) to 12 ± 11 (A1B) mW m−2 compared to 6.6 ± 2.2 mW m−2 in 2000.
Surface/bulk partitioning and acid/base speciation of aqueous decanoate: direct observations and atmospheric implications
Authors: Prisle N. L. , Ottosson N. , Öhrwall G. , Söderström J. , Dal Maso M. , Björneholm O.
Published: December 2012

Abstract. Dilute aqueous solutions of the atmospheric organic surfactant sodium decanoate have been studied using surface sensitive X-ray photoelectron spectroscopy combined with synchrotron radiation. We studied the decanoate/decanoic acid speciation and preferential adsorption at the vapor–liquid interface, and the responses to mixing in solution with some of the most common atmospheric inorganic ions, Na+, NH4+, Cl−, and SO42−. We observe little or no influence of Na+, Cl−, or SO42− ions, on neither the relative speciation nor the individual adsorption properties of decanoate and decanoic acid. In particular, no significant salting-out effect due to common Na+ cations of the organic and inorganic salts was observed for these solutions. On the other hand, mixing with NH4+ cations resulted in a pronounced surface enhancement of decanoic acid, which is attributed to surface specific acid–base chemistry. These changes in surface/bulk partitioning and surface speciation may significantly affect properties of aqueous droplets containing decanoate/decanoic acid, and potential implications for several processes critical to the climate effects of atmospheric aerosols are discussed.
Evaluation of the shortwave cloud radiative effect over the ocean by use of ship and satellite observations
Authors: Hanschmann T. , Deneke H. , Roebeling R. , Macke A.
Published: December 2012

Abstract. In this study the shortwave cloud radiative effect (SWCRE) over ocean calculated by the ECHAM 5 climate model is evaluated for the cloud property input derived from ship based measurements and satellite based estimates and compared to ship based radiation measurements. The ship observations yield cloud fraction, liquid water path from a microwave radiometer, cloud bottom height as well as temperature and humidity profiles from radiosonde ascents. Level-2 products of the Satellite Application Facility on Climate Monitoring (CM~SAF) from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) have been used to characterize clouds. Within a closure study six different experiments have been defined to find the optimal set of measurements to calculate downward shortwave radiation (DSR) and the SWCRE from the model, and their results have been evaluated under seven different synoptic situations. Four of these experiments are defined to investigate the advantage of including the satellite-based cloud droplet effective radius as additional cloud property. The modeled SWCRE based on satellite retrieved cloud properties has a comparable accuracy to the modeled SWCRE based on ship data. For several cases, an improvement through introducing the satellite-based estimate of effective radius as additional information to the ship based data was found. Due to their different measuring characteristics, however, each dataset shows best results for different atmospheric conditions.
Modeling uncertainties for tropospheric nitrogen dioxide columns affecting satellite-based inverse modeling of nitrogen oxides emissions
Authors: Lin J.-T. , Liu Z. , Zhang Q. , Liu H. , Mao J. , Zhuang G.
Published: December 2012

Abstract. Errors in chemical transport models (CTMs) interpreting the relation between space-retrieved tropospheric column densities of nitrogen dioxide (NO2) and emissions of nitrogen oxides (NOx) have important consequences on the inverse modeling. They are however difficult to quantify due to lack of adequate in situ measurements, particularly over China and other developing countries. This study proposes an alternate approach for model evaluation over East China, by analyzing the sensitivity of modeled NO2 columns to errors in meteorological and chemical parameters/processes important to the nitrogen abundance. As a demonstration, it evaluates the nested version of GEOS-Chem driven by the GEOS-5 meteorology and the INTEX-B anthropogenic emissions and used with retrievals from the Ozone Monitoring Instrument (OMI) to constrain emissions of NOx. The CTM has been used extensively for such applications. Errors are examined for a comprehensive set of meteorological and chemical parameters using measurements and/or uncertainty analysis based on current knowledge. Results are exploited then for sensitivity simulations perturbing the respective parameters, as the basis of the following post-model linearized and localized first-order modification. It is found that the model meteorology likely contains errors of various magnitudes in cloud optical depth, air temperature, water vapor, boundary layer height and many other parameters. Model errors also exist in gaseous and heterogeneous reactions, aerosol optical properties and emissions of non-nitrogen species affecting the nitrogen chemistry. Modifications accounting for quantified errors in 10 selected parameters increase the NO2 columns in most areas with an average positive impact of 18% in July and 8% in January, the most important factor being modified uptake of the hydroperoxyl radical (HO2) on aerosols. This suggests a possible systematic model bias such that the top-down emissions will be overestimated by the same magnitude if the model is used for emission inversion without corrections. The modifications however cannot eliminate the large model underestimates in cities and other extremely polluted areas (particularly in the north) as compared to satellite retrievals, likely pointing to underestimates of the a priori emission inventory in these places with important implications for understanding of atmospheric chemistry and air quality. Note that these modifications are simplified and should be interpreted with caution for error apportionment.
A new disjunct eddy-covariance system for BVOC flux measurements – validation on CO2 and H2O fluxes
Authors: Baghi R. , Durand P. , Jambert C. , Jarnot C. , Delon C. , Serça D. , Striebig N. , Ferlicoq M. , Keravec P.
Published: December 2012

Abstract. The disjunct eddy covariance (DEC) method is an interesting alternative to the conventional eddy covariance (EC) method because it allows the estimation of turbulent fluxes of species for which fast sensors are not available. We have developed and validated a new disjunct sampling system (called MEDEE). This system is built with chemically inert materials. Air samples are taken quickly and alternately in two cylindrical reservoirs, the internal pressures of which are regulated by a moving piston. The MEDEE system was designed to be operated either on the ground or aboard an aircraft. It is also compatible with most analysers since it transfers the air samples at a regulated pressure. To validate the system, DEC and EC measurements of CO2 and latent heat fluxes were performed concurrently during a field campaign. EC fluxes were first compared to simulated DEC (SDEC) fluxes and then to actual DEC fluxes. Both the simulated and actual DEC fluxes showed a good agreement with EC fluxes in terms of correlation. The determination coefficients (R2) were 0.93 and 0.91 for DEC and SDEC latent heat fluxes, respectively. For DEC and SDEC CO2 fluxes R2 was 0.69 in both cases. The conditions of low fluxes experienced during the campaign impaired the comparison of the different techniques especially for CO2 flux measurements. Linear regression analysis showed an 14% underestimation of DEC fluxes for both CO2 and latent heat compared to EC fluxes. A first field campaign, focusing on biogenic volatile organic compound (BVOC) emissions, was carried out to measure isoprene fluxes above a downy oak (Quercus Pubescens) forest in the south-east of France. The measured standard emission rate was in the lower range of reported values in earlier studies. Further analysis will be conducted through ground-based and airborne campaigns in the coming years.
ULF wave activity during the 2003 Halloween superstorm: multipoint observations from CHAMP, Cluster and Geotail missions
Authors: Balasis G. , Daglis I. A. , Zesta E. , Papadimitriou C. , Georgiou M. , Haagmans R. , Tsinganos K.
Published: December 2012

Abstract. We examine data from a topside ionosphere and two magnetospheric missions (CHAMP, Cluster and Geotail) for signatures of ultra low frequency (ULF) waves during the exceptional 2003 Halloween geospace magnetic storm, when Dst reached ~−380 nT. We use a suite of wavelet-based algorithms, which are a subset of a tool that is being developed for the analysis of multi-instrument multi-satellite and ground-based observations to identify ULF waves and investigate their properties. Starting from the region of topside ionosphere, we first present three clear and strong signatures of Pc3 ULF wave activity (frequency 15–100 mHz) in CHAMP tracks. We then expand these three time intervals for purposes of comparison between CHAMP, Cluster and Geotail Pc3 observations but also to be able to search for Pc4–5 wave signatures (frequency 1–10 mHz) into Cluster and Geotail measurements in order to have a more complete picture of the ULF wave occurrence during the storm. Due to the fast motion through field lines in a low Earth orbit (LEO) we are able to reliably detect Pc3 (but not Pc4–5) waves from CHAMP. This is the first time, to our knowledge, that ULF wave observations from a topside ionosphere mission are compared to ULF wave observations from magnetospheric missions. Our study provides evidence for the occurrence of a number of prominent ULF wave events in the Pc3 and Pc4–5 bands during the storm and offers a platform to study the wave evolution from high altitudes to LEO. The ULF wave analysis methods presented here can be applied to observations from the upcoming Swarm multi-satellite mission of ESA, which is anticipated to enable joint studies with the Cluster mission.
Nutritive and photosynthetic ecology of subsurface chlorophyll maxima in Canadian Arctic waters
Authors: Martin J. , Tremblay J. É. , Price N. M.
Published: December 2012

Abstract. Assessments of carbon and nitrogen (N) assimilation in Canadian Arctic waters confirmed the large contribution of subsurface chlorophyll maxima (SCM) to total water-column production from spring to late fall. Although SCM communities showed acclimation to low irradiance and greater nitrate (NO3−) availability, their productivity was generally constrained by light and temperature. During spring–early summer, most of the primary production at the SCM was sustained by NO3−, with an average f-ratio (i.e., relative contribution of NO3− uptake to total N uptake) of 0.74 ± 0.26. The seasonal decrease in NO3− availability and irradiance, coupled to the build up of ammonium (NH4+), favoured a transition toward a predominantly regenerative system (f-ratio = 0.37 ± 0.20) during late summer and fall. Results emphasize the need to adequately consider SCM when estimating primary production and to revisit ecosystem model parameters in highly stratified Arctic waters.
Inter-annual variation of carbon uptake by a plantation oak woodland in south-eastern England
Authors: Wilkinson M. , Eaton E. L. , Broadmeadow M. S. J. , Morison J. I. L.
Published: December 2012

Abstract. The carbon balance of an 80-yr-old deciduous oak plantation in the temperate oceanic climate of the south-east of Great Britain was measured by eddy covariance over 12 yr (1999–2010). The mean annual net ecosystem productivity (NEP) was 486 g C m−2 yr−1 (95% CI of ±73 g C m−2 yr−1), and this was partitioned into a gross primary productivity (GPP) of 2034 ± 145 g C m−2 yr−1, over a 165 (±6) day growing season, and an annual loss of carbon through respiration and decomposition (ecosystem respiration, Reco) of 1548 ± 122 g C m−2 yr−1. Although the maximum variation of NEP between years was large (333 g C m−2 yr−1), the ratio of Reco/GPP remained relatively constant (0.76 ± 0.02 CI). Some anomalies in the annual patterns of the carbon balance could be linked to particular weather events, such as low summer solar radiation and low soil moisture content (values below 30% by volume). The European-wide heat wave and drought of 2003 did not reduce the NEP of this woodland because of good water supply from the surface-water gley soil. The inter-annual variation in estimated intercepted radiation only accounted for ~ 47% of the variation in GPP, although a significant relationship (p < 0.001) was found between peak leaf area index and annual GPP, which modified the efficiency with which incident radiation was used in net CO2 uptake. Whilst the spring start and late autumn end of the net CO2 uptake period varied substantially (range of 24 and 27 days respectively), annual GPP was not related to growing season length. Severe outbreaks of defoliating moth caterpillars, mostly Tortrix viridana L. and Operophtera brumata L., caused considerable damage to the forest canopy in 2009 and 2010, resulting in reduced GPP in these two years. Inter-annual variation in the sensitivity of Reco to temperature was found to be strongly related to summer soil moisture content. The eddy covariance estimates of NEP closely matched mensuration-based estimates, demonstrating that this forest was a substantial sink of carbon over the 12-yr measurement period.
The carbon balance of South America: a review of the status, decadal trends and main determinants
Authors: Gloor M. , Gatti L. , Brienen R. , Feldpausch T. R. , Phillips O. L. , Miller J. , Ometto J. P. , Rocha H. , Baker T. , de Jong B. , Houghton R. A. , Malhi Y. , Aragão L. E. O. C. , Guyot J.-L. , Zhao K. , Jackson R. , Peylin P. , Sitch S. , Poulter B. , Lomas M. , Zaehle S. , Huntingford C. , Levy P. , Lloyd J.
Published: December 2012

Abstract. We summarise the contemporary carbon budget of South America and relate it to its dominant controls: population and economic growth, changes in land use practices and a changing atmospheric environment and climate. Component flux estimate methods we consider sufficiently reliable for this purpose encompass fossil fuel emission inventories, biometric analysis of old-growth rainforests, estimation of carbon release associated with deforestation based on remote sensing and inventories, and agricultural export data. Alternative methods for the estimation of the continental-scale net land to atmosphere CO2 flux, such as atmospheric transport inverse modelling and terrestrial biosphere model predictions, are, we find, hampered by the data paucity, and improved parameterisation and validation exercises are required before reliable estimates can be obtained. From our analysis of available data, we suggest that South America was a net source to the atmosphere during the 1980s (~ 0.3–0.4 Pg C a−1) and close to neutral (~ 0.1 Pg C a−1) in the 1990s. During the latter period, carbon uptake in old-growth forests nearly compensated for the carbon release associated with fossil fuel burning and deforestation. Annual mean precipitation over tropical South America as inferred from Amazon River discharge shows a long-term upward trend. Although, over the last decade dry seasons have tended to be drier, with the years 2005 and 2010 in particular experiencing strong droughts. On the other hand, precipitation during the wet seasons also shows an increasing trend. Air temperatures have also increased slightly. Also with increases in atmospheric CO2 concentrations, it is currently unclear what effect these climate changes are having on the forest carbon balance of the region. Current indications are that the forests of the Amazon Basin have acted as a substantial long-term carbon sink, but with the most recent measurements suggesting that this sink may be weakening. Economic development of the tropical regions of the continent is advancing steadily, with exports of agricultural products being an important driver and witnessing a strong upturn over the last decade.
Bathymetrical distribution and size structure of cold-water coral populations in the Cap de Creus and Lacaze-Duthiers canyons (northwestern Mediterranean)
Authors: Gori A. , Orejas C. , Madurell T. , Bramanti L. , Martins M. , Quintanilla E. , Marti-Puig P. , Lo Iacono C. , Puig P. , Requena S. , Greenacre M. , Gili J.
Published: December 2012

Abstract. Submarine canyons are known as one of the seafloor morphological features where living cold-water coral (CWC) communities develop in the Mediterranean Sea. We investigated the CWC community of the two westernmost submarine canyons of the Gulf of Lions canyon system: the Cap de Creus Canyon (CCC) and Lacaze Duthiers Canyon (LDC). Coral associations have been studied through video material recorded by means of a manned submersible and a remotely operated vehicle. Video transects have been conducted and analyzed in order to obtain information on (1) coral bathymetric distribution and density patterns, (2) size structure of coral populations, and (3) coral colony orientation with respect to the substrate. Madrepora oculata was the most abundant CWC in both canyons, while Lophelia pertusa and Dendrophyllia cornigera mostly occurred as isolated colonies or in small patches. An important exception was detected in a vertical cliff in LDC where a large Lophelia pertusa framework was documented. This is the first record of such an extended L. pertusa framework in the Mediterranean Sea. In both canyons coral populations were dominated by medium and large colonies, but the frequent presence of small-sized colonies also indicate active recruitment. The predominant coral orientation with respect to the substrate (90° and 135°) is probably driven by the current regime as well as by the sediment load transported by the current flows. In general no clear differences were observed between the CWC populations from CCC and LDC, despite large differences in particulate matter between canyons.
The impact of land-use change on floristic diversity at regional scale in southern Sweden 600 BC–AD 2008
Authors: Fredh D. , Broström A. , Rundgren M. , Lagerås P. , Mazier F. , Zillén L.
Published: December 2012

Abstract. This study explores the relationship between land-use and floristic diversity between 600 BC and AD 2008 in the uplands of southern Sweden. We use fossil pollen assemblages and the Regional Estimates of Vegetation Abundance from Large Sites (REVEALS) model to quantitatively reconstruct land-cover at a regional scale. Floristic richness and evenness are estimated using palynological richness and REVEALS-based evenness, respectively. We focus on the period AD 350 to 750 to investigate the impact of an inferred, short-lived (< 200 yr) period of land-use expansion and subsequent land abandonment on vegetation composition and floristic diversity. The observed vegetation response is compared to that recorded during the transition from traditional to modern land-use management at the end of the 19th century. Our results suggest that agricultural land-use was most widespread between AD 350 and 1850, which correlates broadly with high values of palynological richness. REVEALS-based evenness was highest between AD 500 and 1600 which indicates a more equal distribution among taxa during this time interval. Palynological richness increased during the inferred land-use expansion after AD 350 and decreased during the subsequent regression AD 550–750, while REVEALS-based increased throughout this period. The values of palynological richness during the last few decades are within the range observed during the last 1650 yr. However, REVEALS-based evenness shows much lower values during the last century compared to the previous ca. 2600 yr, which indicates that the distribution of present day vegetation is unusual in a millennial perspective. Our results show that regional scale changes in land-use have had clear impacts on floristic diversity in southern Sweden, with a vegetation response time of less than 20 to 50 yr. We show the importance of traditional land-use to attain high biodiversity and suggest that ecosystem management should include a regional landscape perspective.
Downward fluxes of elemental carbon, metals and polycyclic aromatic hydrocarbons in settling particles from the deep Ionian Sea (NESTOR site), Eastern Mediterranean
Authors: Theodosi C. , Parinos C. , Gogou A. , Kokotos A. , Stavrakakis S. , Lykousis V. , Hatzianestis J. , Mihalopoulos N.
Published: December 2012

Abstract. To assess sources and major processes controlling vertical transport of both anthropogenic and natural chemical species in deep basins of the Eastern Mediterranean Sea (SE Ionian Sea, Nestor site), we performed chemical characterization (elemental carbon, major and trace metals and polycyclic aromatic hydrocarbons) of marine sinking particles. Sediment traps were deployed at five successive depths, 700 m, 1200 m, 2000 m, 3200 m and 4300 m from the sea surface, during the period of May 2007 to October 2008. Fluxes of all measured species exhibited minimum values from January to March 2008 and maximum from April to September 2008, with an evident covariance revealing a common and rapid vertical transport mechanism from 700 m down to 4300 m depth. Crustal matter flux from atmospheric deposition plays an important role in the temporal variability of particulate matter with significant contribution from biogenic constituents namely the seasonal succession in the export of planktonic biomass, expressed by particulate organic carbon (POC), carbonates and biogenic Si fluxes (Stavrakakis et al., 2012). Tracers (elemental carbon, retene) of the devastating forest fires occurred in August 2007 in southern Greece, were detected at sediment trap material in all depths with a delay of 15 days at 4300 m, indicating a rapid and well-coupled transport of sinking particulate material between the sea-surface and deep layers of the Eastern Mediterranean Sea. Lateral inputs of pollutants at the deepest trap (4300 m) are probably of importance, due to the influence of deep Adriatic water at the study site.
Assessing the role of dust deposition on phytoplankton ecophysiology and succession in a low-nutrient low-chlorophyll ecosystem: a mesocosm experiment in the Mediterranean Sea
Authors: Giovagnetti V. , Brunet C. , Conversano F. , Tramontano F. , Obernosterer I. , Ridame C. , Guieu C.
Published: December 2012

Abstract. In this study, we investigate the phytoplankton community response, with emphasis on ecophysiology and succession, after two experimental additions of Saharan dust in the surface layer of a low-nutrient low-chlorophyll ecosystem in the Mediterranean Sea. Three mesocosms were amended with evapocondensed dust to simulate realistic Saharan dust events while three additional mesocosms were kept unamended and served as controls. Experiments consisted in two consecutive dust additions and samples were daily collected at different depths (−0.1, −5 and −10 m) during one week, starting before each addition occurred. Data concerning HPLC pigment analysis on two size classes (< 3 and > 3 µm), electron transport rate (ETR) versus irradiance curves, non-photochemical fluorescence quenching (NPQ) and phytoplankton cell abundance (measured by flow cytometry), are presented and discussed in this paper. Results show that picophytoplankton mainly respond to the first dust addition, while the second addition leads to an increase of both pico- and nano-/microphytoplankton. Ecophysiological changes in the phytoplankton community are revealed, and an increase in NPQ development, as well as in pigment concentration per cell, follows the dust additions. ETR does not show large variations between dust-amended and control conditions, while biomass increases in response to the dust additions. Furthermore, the biomass increase observed during this mesocosm experiment allows us to attempt a quantitative assessment and parameterization of the onset of a phytoplankton bloom in a nutrient-limited ecosystem. These results are discussed focusing on the adaptation of picophytoplankton to such a nutrient-limited mixed layer system, as well as on size-dependent competition ability in phytoplankton.
Development and comparisons of wind retrieval algorithms for small unmanned aerial systems
Authors: Bonin T. A. , Chilson P. B. , Zielke B. S. , Klein P. M. , Leeman J. R.
Published: December 2012

Abstract. Recently, there has been an increase in use of Unmanned Aerial Systems (UASs) as platforms for conducting fundamental and applied research in the lower atmosphere due to their relatively low cost and ability to collect samples with high spatial and temporal resolution. Concurrent with this development comes the need for accurate instrumentation and measurement methods suitable for small meteorological UASs. Moreover, the instrumentation to be integrated into such platforms must be small and lightweight. Whereas thermodynamic variables can be easily measured using well aspirated sensors onboard, it is much more challenging to accurately measure the wind with a UAS. Several algorithms have been developed that incorporate GPS observations as a means of estimating the horizontal wind vector, with each algorithm exhibiting its own particular strengths and weaknesses. In the present study, the performance of three such GPS-based wind-retrieval algorithms has been investigated and compared with wind estimates from rawinsonde and sodar observations. Each of the algorithms considered agreed well with the wind measurements from sounding and sodar data. Through the integration of UAS-retrieved profiles of thermodynamic and kinematic parameters, one can investigate the static and dynamic stability of the atmosphere and relate them to the state of the boundary layer across a variety of times and locations, which might be difficult to access using conventional instrumentation.