bluuebunny/crossref_metadata_2025 huggingface dataset:
What Do Effective Treatments for Multiple Sclerosis Tell Us about the Molecular Mechanisms Involved in Pathogenesis?
Authors: Buzzard Katherine , Broadley Simon , Butzkueven Helmut
Published: October 2012

Multiple sclerosis is a potentially debilitating disease of the central nervous system. A concerted program of research by many centers around the world has consistently demonstrated the importance of the immune system in its pathogenesis. This knowledge has led to the formal testing of a number of therapeutic agents in both animal models and humans. These clinical trials have shed yet further light on the pathogenesis of MS through their sometimes unexpected effects and by their differential effects in terms of impact on relapses, progression of the disease, paraclinical parameters (MRI) and the adverse events that are experienced. Here we review the currently approved medications for the commonest form of multiple sclerosis (relapsing-remitting) and the emerging therapies for which preliminary results from phase II/III clinical trials are available. A detailed analysis of the molecular mechanisms responsible for the efficacy of these medications in multiple sclerosis indicates that blockade or modulation of both T- and B-cell activation and migration pathways in the periphery or CNS can lead to amelioration of the disease. It is hoped that further therapeutic trials will better delineate the pathogenesis of MS, ultimately leading to even better treatments with fewer adverse effects.
Amazon Rainforest Deforestation Daily Detection Tool Using Artificial Neural Networks and Satellite Images
Authors: Nunes Kehl Thiago , Todt Viviane , Veronez Mauricio Roberto , Cazella Silvio
Published: October 2012

The main purpose of this work was the development of a tool to detect daily deforestation in the Amazon rainforest, using satellite images from the MODIS/TERRA [1] sensor and Artificial Neural Networks. The developed tool provides the parameterization of the configuration for the neural network training to enable us to find the best neural architecture to address the problem. The tool makes use of confusion matrixes to determine the degree of success of the network. Part of the municipality of Porto Velho, in Rondônia state, is located inside the tile H11V09 of the MODIS/TERRA sensor, which was used as the study area. A spectrum-temporal analysis of this area was made on 57 images from 20 of May to 15 of July 2003 using the trained neural network. This analysis allowed us to verify the quality of the implemented neural network classification as well as helping our understanding of the dynamics of deforestation in the Amazon rainforest. The great potential of neural networks for image classification was perceived with this work. However, the generation of consistent alarms, in other words, detecting predatory actions at the beginning; instead of firing false alarms is a complex task that has not yet been solved. Therefore, the major contribution of this paper is to provide a theoretical basis and practical use of neural networks and satellite images to combat illegal deforestation.
Modelling the Course of an HIV Infection: Insights from Ecology and Evolution
Authors: Alizon Samuel , Magnus Carsten
Published: October 2012

The Human Immunodeficiency Virus (HIV) is one of the most threatening viral agents. This virus infects approximately 33 million people, many of whom are unaware of their status because, except for flu-like symptoms right at the beginning of the infection during the acute phase, the disease progresses more or less symptom-free for 5 to 10 years. During this asymptomatic phase, the virus slowly destroys the immune system until the onset of AIDS when opportunistic infections like pneumonia or Kaposi’s sarcoma can overcome immune defenses. Mathematical models have played a decisive role in estimating important parameters (e.g., virion clearance rate or life-span of infected cells). However, most models only account for the acute and asymptomatic latency phase and cannot explain the progression to AIDS. Models that account for the whole course of the infection rely on different hypotheses to explain the progression to AIDS. The aim of this study is to review these models, present their technical approaches and discuss the robustness of their biological hypotheses. Among the few models capturing all three phases of an HIV infection, we can distinguish between those that mainly rely on population dynamics and those that involve virus evolution. Overall, the modeling quest to capture the dynamics of an HIV infection has improved our understanding of the progression to AIDS but, more generally, it has also led to the insight that population dynamics and evolutionary processes can be necessary to explain the course of an infection.
Sodium-iodide symporter positive cells after intracellular uptake of 99mTc versus α-emitter 211At
Authors: Wendisch M. , Freudenberg R. , Runge R. , Oehme L. , Meyer G.J. , Kunz-Schughart L. A. , Wunderlich G. , Kotzerke J.
Published: October 2012

Purpose: We evaluated the DNA damaging potential of Auger electrons emitted in the decay of 99mTc compared to α-particles of 211At. Material and methods: The impact of 99mTc and 211At was monitored in a NIS-expressing rat thyroid cell model PC Cl3 with varying, yet defined intra- and extracellular radionuclide distribution (using ± perchlorate). The radiotoxicity of 99mTc and 211At was studied by the comet assay under neutral and alkaline conditions and colony formation. Results: In the presence of perchlorate, the radioactivity yielding 37 % cellular survival, A37, was estimated to be (0.27 ± 0.02) MBq/ml and (450 ± 30) MBq/ml for 211At and 99mTc, respectively. In absence of perchlorate, cellular radiotracer uptake was similar for both radionuclides (2.2 %, 2.7 %), yet the A37 was reduced by 82% for the α-emitter and by 95 % for 99mTc. Cellular dose increased by a factor of 5 (211At) and 38 (99mTc). Comet assays revealed an increased DNA damage after intracellular uptake of both radiotracers. Conclusions: The data indicate damage to the cell to occur from absorbed dose without recognizable contribution from intracellular heterogeneity of radionuclide distribution. Comet assay under alkaline and neutral conditions did not reveal any shift to more complex DNA damage after radionuclide uptake. Cellular uptake of 99mTc and 211At increased cellular dose and reduced clonogenic survival.
Salafis in parliament: Democratic Attitudes and party politics in the gulf
Authors: Monroe Steve L.
Published: October 2012

This article explores how political participation affects the attitudes of Kuwait's and Bahrain's Salafi parliamentarians towards democracy. In comparing the two states' Salafi parliamentary blocs, this study reveals that neither political inclusion nor ideology uniformly dictates either
bloc's democratic sentiments. Instead, political incentives, as shaped by their state's unique political environments, colors and contrasts both blocs' democratic attitudes and policies. Like their liberal rivals, Salafi parliamentarians are susceptible to the rewards and realities of political
power.
Assessing the plasmonics of gold nano-triangles with higher order laser modes
Authors: Hennemann Laura E , Kolloch Andreas , Kern Andreas , Mihaljevic Josip , Boneberg Johannes , Leiderer Paul , Meixner Alfred J , Zhang Dai
Published: October 2012

Regular arrays of metallic nano-triangles – so called Fischer patterns – are fabricated by nano-sphere lithography. We studied such gold nano-triangle arrays on silicon or glass substrates. A series of different samples was investigated with a parabolic mirror based confocal microscope where the sample is scanned through the laser focus. By employing higher order laser modes (azimuthally and radially polarised laser beams), we can excite the Fischer patterns using either a pure in-plane (x,y) electric field or a strongly z-directional (optical axis of the optical microscope) electric field. We collected and evaluated the emitted luminescence and thereby investigated the respectively excited plasmonic modes. These varied considerably: firstly with the light polarisation in the focus, secondly with the aspect ratio of the triangles and thirdly with the employed substrate. Moreover, we obtained strongly enhanced Raman spectra of an adenine (sub-)monolayer on gold Fischer patterns on glass. We thus showed that gold Fischer patterns are promising surface-enhanced Raman scattering (SERS) substrates.
Organocatalytic tandem Michael addition reactions: A powerful access to the enantioselective synthesis of functionalized chromenes, thiochromenes and 1,2-dihydroquinolines
Authors: Bhanja Chittaranjan , Jena Satyaban , Nayak Sabita , Mohapatra Seetaram
Published: October 2012

Enantioselective organocatalysis has become a field of central importance within asymmetric chemical synthesis and appears to be efficient approach toward the construction of complex chiral molecules from simple achiral materials in one-pot transformations under mild conditions with high stereocontrol. This review addresses the most significant synthetic methods reported on chiral-amine-catalyzed tandem Michael conjugate addition of heteroatom-centered nucleophiles to α,β-unsaturated compounds followed by cyclization reactions for the enantioselective construction of functionalized chiral chromenes, thiochromenes and 1,2-dihydroquinolines in optically enriched forms found in a myriad of bioactive natural products and synthetic compounds.
Enantioselective total synthesis of (R)-(−)-complanine
Authors: Kamanos Krystal A D , Withey Jonathan M
Published: October 2012

A route is described for the enantioselective synthesis of (R)-(−)-complanine, a marine natural product isolated from Eurythoe complanata, and known to be a causative agent in inflammation. An organocatalytic, asymmetric oxyamination of a homoconjugated all-Z-dienal intermediate provides versatile and efficient access to the natural product.
SYSTEMIC RISK IN TAIWAN STOCK MARKET
Authors: Sheu Her-Jiun , Cheng Chien-Ling
Published: October 2012

Recent financial crises resulted from systemic risk caused by idiosyncratic distress. In this research, taking Taiwan stock market as an example and collecting data from 2000 to 2010 which contained the 2001 dot-com bubble and the 2007–2009 financial crisis, we adopt the CoVaR model to empirically explore the impact of sector-specific idiosyncratic risk on the systemic risk of the system and attempt to investigate the links between financial crises, systemic risk and the idiosyncratic risk of a sector-specific anomaly. The result showed sector-specific marginal CoVaR, i.e., ΔCoVaR, perfectly explained Taiwan stock market disturbance during the 2001 dot-com bubble and 2007–2008 financial crisis. Thus, by identifying the larger ΔCoVaR sectors, i.e. the systemic importance sectors, and by exploring the risk indicators, independent variables, of these systemic importance sectors, investors could practically employ the sector-specific ΔCoVaR measure to deepen the systemic risk scrutiny from a macro into a micro prudential perspective.
SMES’ INVESTMENT DETERMINANTS: EMPIRICAL EVIDENCE USING QUANTILE APPROACH
Authors: Nunes Paulo Maçãs , Mendes Sílvia , Serrasqueiro Zélia
Published: October 2012

This paper makes an important contribution to the literature on SMEs, namely investigating whether the relationships between determinants and investment are dependent on the level of investment. Based on a sample of Portuguese SMEs, using two-step estimation method, firstly using probit regression and secondly using quantile regressions, we find significant non-linearities in relationships formed between determinants and investment over the distribution of investment. In particular, we find that: 1) sales, age and growth opportunities are restrictive determinants of investment for low levels of investment, but positive determinants of investment for high levels of investment; 2) debt and the interest rate are restrictive determinants of investment but only for low and intermediate levels of investment; 3) cash flow is a positive determinant of investment, but is more important for investment regarding low levels of investment; 4) GNP is a positive determinant of investment, but only for high levels of investment; and 5) investment in the previous period is a positive determinant of investment in the present period, but only for intermediate and high levels of investment. The relevance of the various theories explaining firm investment depends on SMEs’ level of investment.
A GROWTH MODEL FOR THE QUADRUPLE HELIX
Authors: Afonso Oscar , Monteiro Sara , Thompson Maria
Published: October 2012

We develop a R&D-based growth model with productive public expenditure in order to frame the Quadruple Helix (QH) innovation concept, based on four helices: Academia & Technological Infrastructures, Firms, Government and Civil Society. Our motivation stems from acknowledgment that the relationship between these four helices and their joint impact on growth is in need of a theoretical framework. We aim to emphasise the importance to economic growth of innovation systems structured on these four helices. The introduced model confirms theoretically the notion that increases in: (i) complementarities between distinct productive units, or (ii) in productive government expenditure, lead to higher growth.
DEVELOPING A HYBRID DATA MINING APPROACH BASED ON MULTI-OBJECTIVE PARTICLE SWARM OPTIMIZATION FOR SOLVING A TRAVELING SALESMAN PROBLEM
Authors: Haeri Abdorrahman , Tavakkoli-Moghaddam Reza
Published: October 2012

A traveling salesman problem (TSP) is an NP-hard optimization problem. So it is necessary to use intelligent and heuristic methods to solve such a hard problem in a less computational time. This paper proposes a novel hybrid approach, which is a data mining (DM) based on multi-objective particle swarm optimization (MOPSO), called intelligent MOPSO (IMOPSO). The first step of the proposed IMOPSO is to find efficient solutions by applying the MOPSO approach. Then, the GRI (Generalized Rule Induction) algorithm, which is a powerful association rule mining, is used for extracting rules from efficient solutions of the MOPSO approach. Afterwards, the extracted rules are applied to improve solutions of the MOPSO for large-sized problems. Our proposed approach (IMOPSP) conforms to a standard data mining framework is called CRISP-DM and is performed on five standard problems with bi-objectives. The associated results of this approach are compared with the results obtained by the MOPSO approach. The results show the superiority of the proposed IMOPSO to obtain more and better solutions in comparison to the MOPSO approach.
FORECASTING GOLD PRICE CHANGES BY USING ADAPTIVE NETWORK FUZZY INFERENCE SYSTEM
Authors: Yazdani-Chamzini Abdolreza , Yakhchali Siamak Haji , Volungevičienė Diana , Zavadskas Edmundas Kazimieras
Published: October 2012

Developing a precise and accurate model of gold price is critical to assets management because of its unique features. In this paper, adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) model have been used for modeling the gold price, and compared with the traditional statistical model of ARIMA (autoregressive integrated moving average). The three performance measures, the coefficient of determination (R 2), root mean squared error (RMSE), mean absolute error (MAE), are utilized to evaluate the performances of different models developed. The results show that the ANFIS model outperforms other models (i.e. ANN and ARIMA model), in terms of different performance criteria during the training and validation phases. Sensitivity analysis showed that the gold price changes are highly dependent upon the values of silver price and oil price.
RESEARCH ON FUTURES TREND TRADING STRATEGY BASED ON SHORT TERM CHART PATTERN
Authors: Masteika Saulius , Rutkauskas Aleksandras Vytautas
Published: October 2012

The main task of this paper is to examine a short term trend trading strategy in futures market based on chart pattern recognition, time series and computational analysis. Specifications of historical data for technical analysis and equations for futures profitability calculations together with position size measurement are also discussed in the paper. A contribution of this paper lies in a novel chart pattern related to fractal formation and chaos theory and its application to short term up-trend trading. Trading strategy was tested with historical data of the most active futures contracts. The results have given significantly better and stable returns compared to the change of market benchmark (CRB index). The results of experimental research related to the size of trading portfolio and trade execution slippage are also discussed in the paper. The proposed strategy can be attractive for futures market participants and be applied as a decision support tool in technical analysis.
Mouse CD11b+Gr-1+ Myeloid Cells Can Promote Th17 Cell Differentiation and Experimental Autoimmune Encephalomyelitis
Authors: Yi Huanfa , Guo Chunqing , Yu Xiaofei , Zuo Daming , Wang Xiang-Yang
Published: October 2012

Myeloid-derived suppressor cells (MDSCs) have been a focus of recent study on tumor-mediated immune suppression. However, its role in Th17 cell differentiation and the pathogenesis of autoimmune diseases (e.g., multiple sclerosis) has not been determined. We show in this study that development of experimental autoimmune encephalomyelitis (EAE) in mice is associated with a profound expansion of CD11b+Gr-1+ MDSCs, which display efficient T cell inhibitory functions in vitro. Unexpectedly, these MDSCs enhance the differentiation of naive CD4+ T cell precursors into Th17 cells in a highly efficient manner under Th17-polarizing conditions, as indicated by significantly increased number of Th17 cells, elevation of IL-17A production, and upregulation of the orphan nuclear receptor RORA and RORC. Mechanistic studies show that IL-1β represents a major mediator of MDSC-facilitated Th17 differentiation, which depends on the IL-1 receptor on CD4+ T cells but not MDSCs. Selective depletion of MDSCs using gemcitabine results in a marked reduction in the severity of EAE (e.g., decreased clinical scores and myelin injury), which correlates with reduced Th17 cells and inflammatory cytokines (IL-17A and IL-1β) in the lymphoid tissues and spinal cord. Adoptive transfer of MDSCs after gemcitabine treatment restores EAE disease progression. Together, we demonstrate for the first time, to our knowledge, that excessive and prolonged presence of MDSCs can drive a Th17 response and consequently contributes to the pathogenesis of EAE. These new findings provide unique insights into the pleiotropic functions of MDSCs and may help explain the failure of immunosuppressive MDSCs to control Th17/IL-17–dependent autoimmune disorders.
Reconstitution of Protective Immune Responses against Cytomegalovirus and Varicella Zoster Virus Does Not Require Disease Development in Pediatric Recipients of Umbilical Cord Blood Transplantation
Authors: Merindol Natacha , Salem Fourati Insaf , Brito Rose-Marie , Grenier Anne-Julie , Charrier Emily , Cordeiro Paulo , Caty Martine , Mezziani Samira , Malette Brigitte , Duval Michel , Alfieri Carolina , Ovetchkine Philippe , Le Deist Françoise , Soudeyns Hugo
Published: October 2012

CMV and varicella zoster virus (VZV) are significant causes of morbidity and mortality following umbilical cord blood transplantation (UCBT). However, the kinetics of reconstitution and protective potential of antiviral cell-mediated immune responses following UCBT remain poorly characterized. In this study, the reconstitution of CMV- and VZV-specific T cell responses was assessed using IFN-γ ELISPOT in 28 children who underwent UCBT to treat hematological or inherited disorders. Barely detectable in the first 3 mo posttransplantation, CMV- and VZV-specific T cell responses were observed in 30.4% and 40.3% of study subjects after 36 mo of follow-up. Four of five CMV-seropositive subjects developed detectable levels of circulating CMV DNA (DNAemia), and 5 of 17 VZV-seropositive patients experienced herpes zoster during the posttransplant period. Four CMV-seronegative subjects developed IFN-γ responses against CMV, and four subjects developed a VZV-specific IFN-γ response without clinical signs of infection. No CMV- or VZV-related events were observed in study subjects following the development of CMV- or VZV-specific responses > 150 spot-forming units/106 PBMCs, consistent with T cell-mediated protection. Finally, famciclovir prophylaxis did not strictly prevent the reconstitution of the VZV-specific T cell repertoire, because the frequency of T cells producing IFN-γ in response to VZV Ags reached levels consistent with protection in two nonzoster subjects. Monitoring of CMV- and VZV-specific cell-mediated immunity could inform immunocompetence and guide the initiation and cessation of antiherpetic prophylaxis in UCBT recipients.
IFN-α in the Treatment of Melanoma
Authors: Tarhini Ahmad A. , Gogas Helen , Kirkwood John M.
Published: October 2012

Among the IFNs, IFN-α2 has been the most broadly evaluated clinically. At the molecular level, IFN-α has multiple effects in a variety of malignancies that range from antiangiogenic to potent immunoregulatory, differentiation-inducing, antiproliferative, and proapoptotic effects. A multitude of IFN-α2 regimens that may be classified as low dose, intermediate dose, and high dose have been evaluated as adjuvant therapy in melanoma. A durable impact on both relapse-free and overall survival was seen only with the regimen utilizing high-dose IFN-α2b tested in the Eastern Cooperative Oncology Group and intergroup trials E1684, E1690, and E1694 as adjuvant therapy for high-risk surgically resected melanoma (stage IIB or III). Adjuvant pegylated IFN-α2b has also been evaluated at maximally tolerable doses compared with the observation group in the European Organization for Research and Treatment of Cancer trial 18991 and has shown relapse-free survival benefits in patients with microscopic nodal disease.
The prevalence of peripheral arterial disease in diabetic subjects in south-west Nigeria
Authors: Oyelade Bolaji O. , OlaOlorun Akintayo D. , Odeigah Louis O. , Amole Isaac O. , Adediran Olufemi S.
Published: October 2012

Background: Peripheral arterial disease (PAD) is rarely sought for and generally underdiagnosed even in diabetics in developing countries like Nigeria. PAD is easily detected and diagnosed by the ankle-brachial index, a simple and reliable test. Objectives: To determine the prevalence of PAD in diabetic subjects aged 50–89 years and the value of ankle-brachial index measurement in the detection of PAD.Method: A cross-sectional descriptive study of 219 diabetic subjects aged 50–89 years was carried out. The participants were administered a pre-tested questionnaire and measurement of ankle-brachial index (ABI) was done. The ankle-brachial index < 0.90 was considered equivalent to peripheral arterial disease.Results: The overall prevalence of PAD was 52.5%. The prevalence of symptomatic PAD was 28.7% whilst that of asymptomatic PAD was 71.3%. There were a number of associations with PAD which included, age (p < 0.05), sex (p < 0.05), and marital status (p < 0.05). The use of the ankle-brachial index in the detection of PAD was clearly more reliable than the clinical methods like history of intermittent claudication and absence or presence of pedal pulses.Conclusion: The prevalence of PAD is relatively high in diabetic subjects in the southwestern region of Nigeria. Notable is the fact that a higher proportion was asymptomatic. Also the use of ABI is of great value in the detection of PAD as evidenced by a clearly more objective assessment of PAD compared to both intermittent claudication and absent pedal pulses.
The History of Dengue Outbreaks in the Americas
Authors: Brathwaite Dick Olivia , San Martín José L. , Montoya Romeo H. , del Diego Jorge , Zambrano Betzana , Dayan Gustavo H.
Published: October 2012

Dengue is a viral disease usually transmitted by Aedes aegypti mosquitoes. Dengue outbreaks in the Americas reported in medical literature and to the Pan American Health Organization are described. The outbreak history from 1600 to 2010 was categorized into four phases: Introduction of dengue in the Americas (1600–1946); Continental plan for the eradication of the Ae. aegypti (1947–1970) marked by a successful eradication of the mosquito in 18 continental countries by 1962; Ae. aegypti reinfestation (1971–1999) caused by the failure of the mosquito eradication program; Increased dispersion of Ae. aegypti and dengue virus circulation (2000–2010) characterized by a marked increase in the number of outbreaks. During 2010 > 1.7 million dengue cases were reported, with 50,235 severe cases and 1,185 deaths. A dramatic increase in the number of outbreaks has been reported in recent years. Urgent global action is needed to avoid further disease spread.
A 24-year-old Ethiopian Farmer with Burning Feet
Authors: Visser Benjamin Jelle , Korevaar Daniel Arnoldus , van der Zee Janneke
Published: October 2012

Podoconiosis is a non-infectious tropical disease caused by exposure of bare feet to irritant alkalic clay soils. This causes an asymmetrical swelling of the feet and lower limbs due to lymphoedema. This swelling is called “elephantiasis” and may lead to severe disability of the patient. It is found in areas of tropical Africa, Central and South America and north-west India, where such soils coexist with high altitude, high seasonal rainfall and low income. Social stigmatization of people with the disease is widespread and economic losses are enormous. Podoconiosis is unique in being an entirely preventable non-communicable tropical disease. However, so far it has received little attention from health care policy makers.
Implications of nitrogen‐rich glacial meltwater for phytoplankton diversity and productivity in alpine lakes
Authors: Slemmons Krista E. H. , Saros Jasmine E.
Published: October 2012

We compared phytoplankton diversity and productivity over various time scales in a set of lakes in the central Rocky Mountains of North America (fed by both glacial and snowpack meltwaters [GSF] and by snowpack alone [SF]) to better understand the influence of nitrogen‐rich glacial meltwater on the structure and function of phytoplankton. Nitrate concentrations in GSF lakes were on average 44 times higher than in SF, even though only 0.01–0.59% of the catchment area of GSF lakes was covered by glaciers. In three lakes of each type, we determined the vertical distribution of algae, epilimnetic primary productivity rates, and nutrient‐limitation patterns. Phytoplankton richness and community structure were compared between lake types in the nutrient enrichment experiments, as well as in the tops (i.e., modern) and bottoms (circa 1850) of sediment cores from four lakes of each type. Average primary productivity rates were five times higher in GSF lakes, but vertically integrated chlorophyll concentrations did not differ. However, algal biomass was higher in the epi‐ and metalimnion of GSF lakes, while it was equivalent in the hypolimnion of both lake types. Nutrient‐limitation patterns differed between lake types, with GSF lakes limited by phosphorus and most SF lakes co‐limited by nitrogen and phosphorus. Modern diatom species richness was lower in GSF compared with SF lakes, whereas differences between lake types were not apparent during the mid‐19th century. Key differences in the structure and function of GSF compared with SF lakes imply that GSF lakes will take a different ecological trajectory if glaciers disappear.
Spatial heterogeneity strongly affects estimates of ecosystem metabolism in two north temperate lakes
Authors: Van de Bogert Matthew C. , Bade Darren L. , Carpenter Stephen R. , Cole Jonathan J. , Pace Michael L. , Hanson Paul C. , Langman Owen C.
Published: October 2012

To characterize the spatial variability of metabolism estimates (gross primary production [GPP], respiration [R], and net ecosystem production [NEP]) in two Northern Wisconsin lakes, we collected data from 27 and 35 dissolved oxygen sensors placed in a two‐dimensional array throughout the upper mixed layers over a period of 10 d per lake in midsummer. Averaged over the deployment, aerial metabolism estimates among sensor locations varied 1–2 orders of magnitude and were largely unrelated to physical habitat within the lake. For all sites and days, 76–90% of the explainable variance in GPP and R was attributable to location in the lake rather than day of the deployment. NEP, on the other hand, was less affected by location, with 79–93% of the explained variance attributable to the day of the deployment. Single‐location estimates can yield errors of more than an order of magnitude in estimates of daily GPP and R and can mischaracterize the trophic status of the lake. Using a rarefaction approach, we found that using four randomly placed sensors increased the precision of the resulting daily metabolism estimates fourfold over single‐location measures in both lakes.
Gill surface area and metabolic enzyme activities of demersal fishes associated with the oxygen minimum zone off California
Authors: Friedman Jason R. , Condon Nicole E. , Drazen Jeffrey C.
Published: October 2012

Metabolic enzyme activities and gill surface areas were measured across 10 species of demersal fishes from Monterey Canyon, California, which features a prominent oxygen minimum zone (OMZ). Comparisons were made between species living both within and outside of the OMZ. Enzyme activities showed no significant trend toward aerobic suppression or heightened reliance on anaerobic metabolism in response to the OMZ. While flatfish species living both within and outside of the OMZ had similarly low enzyme activities, the OMZ‐dwelling Microstomus pacificus had 1.8–3 times larger gill surface area than comparably sized flatfishes from higher‐oxygen waters, suggesting a morphological adaptation to low oxygen. In scorpaeniform fishes, high aerobic metabolism was accompanied by large gill surface areas in two routine‐swimming OMZ‐dwelling species (Anoplopoma fimbria and Careproctus melanurus). Low aerobic activities and small gills were found in two Sebastolobus species, suggesting a low oxygen demand resulting from a more sedentary behavior compared to other Scorpaeniformes. In gadiform fishes, no differences were measured in enzyme activity levels, but larger gill surface areas were measured in OMZ‐dwelling Nezumia liolepis. These results indicate adaptation to low oxygen in a variety of ways that balance oxygen demand with supply, with no indication that these species rely on enhanced anaerobic metabolism. With both flatfishes and rattails, adaptation to OMZs is demonstrated through increased gill surface area.
Bacterial carbon cycling in a subarctic fjord: A seasonal study on microbial activity, growth efficiency, and virus‐induced mortality in Kobbefjord, Greenland
Authors: Middelboe Mathias , Glud Ronnie N. , Sejr Mikael K.
Published: October 2012

In this seasonal study, we examined the environmental controls and quantitative importance of bacterial carbon consumption in the water column and the sediment in the subarctic Kobbefjord, Greenland. Depth‐integrated bacterial production in the photic zone varied from 5.0 ± 2.7 mg C m−2 d−1 in February to 42 ± 28 mg C m−2 d−1 in May and 34 ± 7 mg C m−2 d−1 in September, corresponding to a bacterial production to primary production ratio of 0.34 ± 0.14, 0.07 ± 0.04, and 0.08 ± 0.06, respectively. Based on measured bacterial growth efficiencies (BGEs) of 0.09–0.10, pelagic bacterial carbon consumption was 54 ± 59 mg C m−2 d−1, 1194 ± 329 mg C m−2 d−1, and 689 ± 115 mg C m−2 d−1 in February, May, and September, respectively, which corresponded to 367%, 71%, and 87% of pelagic primary production. The average annual sediment respiration corresponded to 121 mg C m−2 d−1 and accounted for 17% of total microbial respiration in the system. Concentration of bioavailable dissolved organic carbon (BDOC) ranged from 144 ± 37 µg C L−1 in the riverine input to the fjord to a maximum of 341 ± 37 µg C L−1 in the surface waters in September. Parallel enrichment experiments showed that bacterial production and BGE were positively correlated with BDOC concentration, suggesting that organic carbon availability was limiting bacterial activity and carbon conversion efficiency. Viral production was low (0.8–1.8 × 104 viruses mL−1 h−1) as compared to low‐latitude environments, suggesting a relatively small effect of viruses on bacterial mortality (4–36% of cell production) and carbon cycling. Heterotrophic bacterial consumption was closely coupled with autochthonous BDOC production, and the majority of the primary production was consumed by pelagic bacteria at all seasons. The relatively low measured BGE emphasized the importance of solid on‐site BGE estimates for assessing carbon budgets in marine environments.
Skill-Biased Labor Market Reforms and International Competitiveness
Authors: Schmerer Hans-Jörg
Published: October 2012

This paper proposes a multi-industry trade model with integrated capital and goods markets. Labor market imperfections in line with Mortensen and Pissarides (Job Creation and Job Destruction in the Theory of Unemployment, 1994) give rise to unemployment and a channel for the government to influence markets through institutional changes. Labor market interventions feedback into the product market through changes in a country’s competitiveness. Moreover, the distinction between high- and low-skill workers facilitates the analysis of skillbiased institutional changes that have stronger impact on certain skill groups. The comparative static exercise in this paper shows that high-skilled benefit from low-skill biased labor market reforms through higher wages. Lower labor costs reduce unemployment of the low-skilled and increases the reforming country’s competitiveness. One-sided labor market interventions have feedback effects through adjustments at the extensive margin, which affect all workers at home and abroad irrespective of their level of skill. Governments in the non-reforming countries may react to this loss in competitiveness by initiating cooperative labor market reforms instead.
Modeling the formation and properties of traditional and non-traditional secondary organic aerosol: problem formulation and application to aircraft exhaust
Authors: Jathar S. H. , Miracolo M. A. , Presto A. A. , Donahue N. M. , Adams P. J. , Robinson A. L.
Published: October 2012

Abstract. We present a methodology to model secondary organic aerosol (SOA) formation from the photo-oxidation of unspeciated low-volatility organics (semi-volatile and intermediate volatile organic compounds) emitted by combustion systems. It is formulated using the volatility basis-set approach. Unspeciated low-volatility organics are classified by volatility and then allowed to react with the hydroxyl radical. The new methodology allows for larger reductions in volatility with each oxidation step than previous volatility basis set models, which is more consistent with the addition of common functional groups and similar to those used by traditional SOA models. The methodology is illustrated using data collected during two field campaigns that characterized the atmospheric evolution of dilute gas-turbine engine emissions using a smog chamber. In those experiments, photo-oxidation formed a significant amount of SOA, much of which could not be explained based on the emissions of traditional speciated precursors; we refer to the unexplained SOA as non-traditional SOA (NT-SOA). The NT-SOA can be explained by emissions of unspeciated low-volatility organics measured using sorbents. We show that the parameterization proposed by Robinson et al. (2007) is unable to explain the timing of the NT-SOA formation in the aircraft experiments because it assumes a very modest reduction in volatility of the precursors with every oxidation reaction. In contrast the new method better reproduces the NT-SOA formation. The NT-SOA yields estimated for the unspeciated low-volatility organic emissions in aircraft exhaust are similar to literature data for large n-alkanes and other low-volatility organics. The estimated yields vary with fuel composition (Jet Propellent-8 versus Fischer-Tropsch) and engine load (ground idle versus non-ground idle). The framework developed here is suitable for modeling SOA formation from emissions from other combustion systems.
Adjoint sensitivity of global cloud droplet number to aerosol and dynamical parameters
Authors: Karydis V. A. , Capps S. L. , Russell A. G. , Nenes A.
Published: October 2012

Abstract. We present the development of the adjoint of a comprehensive cloud droplet formation parameterization for use in aerosol-cloud-climate interaction studies. The adjoint efficiently and accurately calculates the sensitivity of cloud droplet number concentration (CDNC) to all parameterization inputs (e.g., updraft velocity, water uptake coefficient, aerosol number and hygroscopicity) with a single execution. The adjoint is then integrated within three dimensional (3-D) aerosol modeling frameworks to quantify the sensitivity of CDNC formation globally to each parameter. Sensitivities are computed for year-long executions of the NASA Global Modeling Initiative (GMI) Chemical Transport Model (CTM), using wind fields computed with the Goddard Institute for Space Studies (GISS) Global Circulation Model (GCM) II', and the GEOS-Chem CTM, driven by meteorological input from the Goddard Earth Observing System (GEOS) of the NASA Global Modeling and Assimilation Office (GMAO). We find that over polluted (pristine) areas, CDNC is more sensitive to updraft velocity and uptake coefficient (aerosol number and hygroscopicity). Over the oceans of the Northern Hemisphere, addition of anthropogenic or biomass burning aerosol is predicted to increase CDNC in contrast to coarse-mode sea salt which tends to decrease CDNC. Over the Southern Oceans, CDNC is most sensitive to sea salt, which is the main aerosol component of the region. Globally, CDNC is predicted to be less sensitive to changes in the hygroscopicity of the aerosols than in their concentration with the exception of dust where CDNC is very sensitive to particle hydrophilicity over arid areas. Regionally, the sensitivities differ considerably between the two frameworks and quantitatively reveal why the models differ considerably in their indirect forcing estimates.
Interpretation of FRESCO cloud retrievals in case of absorbing aerosol events
Authors: Wang P. , Tuinder O. N. E. , Tilstra L. G. , de Graaf M. , Stammes P.
Published: October 2012

Abstract. Cloud and aerosol information is needed in trace gas retrievals from satellite measurements. The Fast REtrieval Scheme for Clouds from the Oxygen A band (FRESCO) cloud algorithm employs reflectance spectra of the O2 A band around 760 nm to derive cloud pressure and effective cloud fraction. In general, clouds contribute more to the O2 A band reflectance than aerosols. Therefore, the FRESCO algorithm does not correct for aerosol effects in the retrievals and attributes the retrieved cloud information entirely to the presence of clouds, and not to aerosols. For events with high aerosol loading, aerosols may have a dominant effect, especially for almost cloud free scenes. We have analysed FRESCO cloud data and Absorbing Aerosol Index (AAI) data from the Global Ozone Monitoring Experiment (GOME-2) instrument on the Metop-A satellite for events with typical absorbing aerosol types, such as volcanic ash, desert dust and smoke. We find that the FRESCO effective cloud fractions are correlated with the AAI data for these absorbing aerosol events and that the FRESCO cloud pressure contains information on aerosol layer pressure. For cloud free scenes, the derived FRESCO cloud pressure is close to the aerosol layer pressure, especially for optically thick aerosol layers. For cloudy scenes, if the strongly absorbing aerosols are located above the clouds, then the retrieved FRESCO cloud pressure may represent the height of the aerosol layer rather than the height of the clouds. Combining FRESCO and AAI data, an estimate for the aerosol layer pressure can be given.
Synthesizing greenhouse gas fluxes across nine European peatlands and shrublands – responses to climatic and environmental changes
Authors: Carter M. S. , Larsen K. S. , Emmett B. , Estiarte M. , Field C. , Leith I. D. , Lund M. , Meijide A. , Mills R. T. E. , Niinemets Ü. , Peñuelas J. , Portillo-Estrada M. , Schmidt I. K. , Selsted M. B. , Sheppard L. J. , Sowerby A. , Tietema A. , Beier C.
Published: October 2012

Abstract. In this study, we compare annual fluxes of methane (CH4), nitrous oxide (N2O) and soil respiratory carbon dioxide (CO2) measured at nine European peatlands (n = 4) and shrublands (n = 5). The sites range from northern Sweden to Spain, covering a span in mean annual air temperature from 0 to 16 °C, and in annual precipitation from 300 to 1300 mm yr−1. The effects of climate change, including temperature increase and prolonged drought, were tested at five shrubland sites. At one peatland site, the long-term (> 30 yr) effect of drainage was assessed, while increased nitrogen deposition was investigated at three peatland sites. The shrublands were generally sinks for atmospheric CH4, whereas the peatlands were CH4 sources, with fluxes ranging from −519 to +6890 mg CH4-C m−2 yr−1 across the studied ecosystems. At the peatland sites, annual CH4 emission increased with mean annual air temperature, while a negative relationship was found between net CH4 uptake and the soil carbon stock at the shrubland sites. Annual N2O fluxes were generally small ranging from −14 to 42 mg N2O-N m−2 yr−1. Highest N2O emission occurred at the sites that had highest nitrate (NO3−) concentration in the soil water. Furthermore, experimentally increased NO3− deposition led to increased N2O efflux, whereas prolonged drought and long-term drainage reduced the N2O efflux. Soil CO2 emissions in control plots ranged from 310 to 732 g CO2-C m−2 yr−1. Drought and long-term drainage generally reduced the soil CO2 efflux, except at a hydric shrubland where drought tended to increase soil respiration. In terms of fractional importance of each greenhouse gas to the total numerical global warming response, the change in CO2 efflux dominated the response in all treatments (ranging 71–96%), except for NO3− addition where 89% was due to change in CH4 emissions. Thus, in European peatlands and shrublands the effect on global warming induced by the investigated anthropogenic disturbances will be dominated by variations in soil CO2 fluxes.
Evaluation of the carbon cycle components in the Norwegian Earth System Model (NorESM)
Authors: Tjiputra J. F. , Roelandt C. , Bentsen M. , Lawrence D. M. , Lorentzen T. , Schwinger J. , Seland Ø. , Heinze C.
Published: October 2012

Abstract. The recently developed Norwegian Earth System Model (NorESM) is employed for simulations contributing to the CMIP5 (Coupled Model Intercomparison Project phase 5) experiments and the fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC-AR5). In this manuscript, we focus on evaluating the ocean and land carbon cycle components of the NorESM, based on the control and historical simulations. Many of the observed large scale ocean biogeochemical features are reproduced satisfactorily by the NorESM. When compared to the climatological estimates from the World Ocean Atlas (WOA), the model simulated temperature, salinity, oxygen, and phosphate distributions agree reasonably well in both the surface layer and deep water structure. However, the model simulates a relatively strong overturning circulation strength that leads to noticeable model-data bias, especially within the North Atlantic Deep Water (NADW). This strong overturning circulation slightly distorts the structure of the biogeochemical tracers at depth. Advancements in simulating the oceanic mixed layer depth with respect to the previous generation model particularly improve the surface tracer distribution as well as the upper ocean biogeochemical processes, particularly in the Southern Ocean. Consequently, near surface ocean processes such as biological production and air-sea gas exchange, are in good agreement with climatological observations. NorESM reproduces the general pattern of land-vegetation gross primary productivity (GPP) when compared to the observationally-based values derived from the FLUXNET network of eddy covariance towers. Globally, the NorESM simulated annual mean GPP and terrestrial respiration are 129.8 and 106.6 Pg C yr−1, slightly larger than observed of 119.4 ± 5.9 and 96.4 ± 6.0 Pg C yr−1. The latitudinal distribution of GPP fluxes simulated by NorESM shows a GPP overestimation of 10% in the tropics and a substantial underestimation of GPP at high latitudes.
Global multi-scale segmentation of continental and coastal waters from the watersheds to the continental margins
Authors: Laruelle G. G. , Dürr H. H. , Lauerwald R. , Hartmann J. , Slomp C. P. , Regnier P. A. G.
Published: October 2012

Abstract. The complex coastline of the Earth is over 400 000 km long and about 40% of the world's population lives within 100 km of the sea. Past characterizations of the global coastline were constructed either from a continental perspective through an analysis of watershed river basin properties (COSCAT: Coastal Segmentation and related CATchments) or from an oceanic perspective, through a regionalization of the proximal and distal continental margins (LME: Large Marine Ecosystems). Here, we present a global-scale coastal segmentation, composed of three consistent levels, that includes the whole aquatic continuum with its riverine, estuarine and shelf sea components. Our work delineates comprehensive ensembles which retain the most important physical characteristics of both the land and shelf areas. The proposed multi-scale segmentation results in a distribution of global exorheic watersheds, estuaries and continental shelf seas among 45 major zones (MARCATS: MARgins and CATchments Segmentation) and 149 sub-units (COSCATS). Geographic and hydrologic parameters such as the surface area, volume and fresh water residence time are calculated for each coastal unit as well as different hypsometric profiles. Our analysis provides detailed insights into the distributions of coastal and continental shelf areas and how they connect with incoming riverine fluxes. These results can be used for regional analyses and combined with various typologies for upscaling and biogeochemical budgets. In addition, the three levels segmentation can be used for application in Earth System analysis.
Paleo ice flow and subglacial meltwater dynamics in Pine Island Bay, West Antarctica
Authors: Nitsche F. O. , Gohl K. , Larter R. , Hillenbrand C.-D. , Kuhn G. , Smith J. , Jacobs S. , Anderson J. , Jakobsson M.
Published: October 2012

Abstract. Increasing evidence for an elaborate subglacial drainage network underneath modern Antarctic ice sheets suggests that basal meltwater has an important influence on ice stream flow. Swath bathymetry surveys from previously glaciated continental margins display morphological features indicative of subglacial meltwater flow in inner shelf areas of some paleo ice stream troughs. Over the last few years several expeditions to the Eastern Amundsen Sea embayment (West Antarctica) have investigated the paleo ice streams that extended from the Pine Island and Thwaites glaciers. A compilation of high-resolution swath bathymetry data from inner Pine Island Bay reveals details of a rough seabed topography including several deep channels that connect a series of basins. This complex basin and channel network is indicative of meltwater flow beneath the paleo-Pine Island and Thwaites ice streams, along with substantial subglacial water inflow from the east. This meltwater could have enhanced ice flow over the rough bedrock topography. Meltwater features diminish with the onset of linear features north of the basins. Similar features have previously been observed in several other areas, including the Dotson-Getz Trough (Western Amundsen Sea embayment) and Marguerite Bay (SW Antarctic Peninsula), suggesting that these features may be widespread around the Antarctic margin and that subglacial meltwater drainage played a major role in past ice-sheet dynamics.