bluuebunny/crossref_metadata_2025 huggingface dataset:
Laboratory Evaluation of Three Regimens of Treatment of Chronic Hepatitis B: Tenofovir, Entecavir and Combination of Lamivudine and Adefovir
Authors: Jayakumar Rajeswari , Joshi Yogendra Kumar , Singh Sarman
Published: July 2012

Background: Chronic hepatitis B is a disease of concern due to its life-threatening complications like cirrhosis, and hepatocellular carcinoma (HCC) in 20-40% of patients. There are about 400 million people affected worldwide with HBV, and over 300,000 die every year from HBV-related diseases. Oral antivirals like lamivudine, adefovir, entecavir, and tenofovir are commonly used to treat chronic hepatitis B. In this study, we tried to evaluate the comparative efficacy of these drugs alone and in combination.

Materials and Methods: Chronic hepatitis B patients with HBV-DNA more than 104 Copies/mL irrespective of their HBeAg status (n = 60) were enrolled in a prospective study. 21, 20, and 19 patients were treated with lamivudine (100 mg/day) plus adefovir (10 mg/day) combination entecavir monotherapy (0.5 mg/day) and tenofovir monotherapy (300 mg/day), respectively and were followed up for 24 weeks with their virological, serological, and biochemical markers measured at 12 and 24 weeks.

Results: After 24 weeks of treatment, there was no significant difference between the 3 groups in suppressing HBV-DNA to undetectable levels. The median decrease in HBV-DNA levels from baseline was better with tenofovir and entecavir monotherapies than lamivudine and adefovir combination, which was statistically significant. There was no significant difference between the 3 groups in HBsAg and HBeAg seroconversion and normalization of biochemical parameters.

Conclusion: Entecavir and tenofovir monotherapy were found to be more effective than lamivudine plus adefovir combination in reducing the HBV-DNA levels. However, lamivudine plus adefovir combination was not too inferior, especially when cost of treatment was taken into consideration.
Florid Erythrophagocytosis on the Peripheral Smear
Authors: Chandrashekar Vani , Soni Mamta
Published: July 2012

anemias and sporadically in few other conditions. Here, we report a case of florid erythrophagocytosis with severe anemia following a viral infection in an 18-year-old girl. Her complete blood count (CBC) revealed hemoglobin of 3.6 gm/dl and a hematocrit of 10%. The peripheral smear showed erythrophagocytosis by neutrophils and rosetting of erythrocytes around neutrophils. The direct Coombs test and direct Donath- Landsteiner tests were positive.
Radioiodine Thyroid Ablation in Graves′ Hyperthyroidism: Merits and Pitfalls
Authors: Nwatsock J. , Taieb D. , Tessonnier L. , Mancini J. , Dong-A-Zok F. , Mundler O.
Published: July 2012

Ablative approaches using radioiodine are increasingly proposed for the treatment of Graves′ disease (GD) but their ophthalmologic and biological autoimmune responses remain controversial and data concerning clinical and biochemical outcomes are limited. The aim of this study was to evaluate thyroid function, TSH-receptor antibodies (TRAb) and Graves′ ophthalmopathy (GO) occurrence after radioiodine thyroid ablation in GD. We reviewed 162 patients treated for GD by iodine-131 (131 I) with doses ranging from 370 to 740 MBq, adjusted to thyroid uptake and sex, over a 6-year period in a tertiary referral center. Collected data were compared for outcomes, including effectiveness of radioiodine therapy (RIT) as primary endpoint, evolution of TRAb, and occurrence of GO as secondary endpoints. The success rate was 88.3% within the first 6 months after the treatment. The RIT failure was increased in the presence of goiter (adjusted odds ratio = 4.1, 95% confidence interval 1.4-12.0, P = 0.010). The TRAb values regressed with time (r = −0.147; P = 0.042) and patients with a favorable outcome had a lower TRAb value (6.5 ± 16.4 U/L) than those with treatment failure (23.7 ± 24.2 U/L, P < 0.001). At the final status, 48.1% of patients achieved normalization of serum TRAb. GO occurred for the first time in 5 patients (3.7%) who were successfully cured for hyperthyroidism but developed early and prolonged period of hypothyroidism in the context of antithyroid drugs (ATD) intolerance (P = 0.003) and high TRAb level (P = 0.012). On the basis the results of this study we conclude that ablative RIT is effective in eradicating Graves′ hyperthyroidism but may be accompanied by GO occurrence, particularly in patients with early hypothyroidism and high pretreatment TRAb and/or ATD intolerance. In these patients, we recommend an early introduction of LT4 to reduce the duration and the degree of the radioiodine-induced hypothyroidism.
BioChroma - A New and Patented Technology for Processing Radioactive Wastewater from Nuclear Medicine Therapy Facilities in Hospitals and Clinics
Authors: Rodríguez José
Published: July 2012

After undergoing radionuclide therapy, patients generate wastewater with a considerable amount of radioactivity, which can reach levels of as much as 90% of the administered dose. Due to the risk of accumulation after discharge into the sewer, it is advisable to collect this effluent for its treatment prior to final discharge. Delay and decay (natural decomposition of the isotope) is the most commonly used technical method of abating radioactive iodine, but it is frequently criticized as being complex and very expensive. BioChroma is a technology that has been developed as an alternative to these complicated and expensive systems. This paper describes this new technology and presents, as an example, a system that was installed and successfully commissioned in the middle of 2008 in a nuclear medicine ward with 12 beds in Stuttgart (Germany). Based on existing legislation, the responsible authorities and the company that operated the hospital agreed on a maximum activity level of 5 Bq/l. If a typical delay and decay system would have been installed, the 180 m³ treatment plant that was already available in the hospital cellar would have to be extended by additional 150 m³. By implementing the patented BioChroma process, the space requirements were reduced by 75%. For instance, since the new system was integrated into the existing installation, tanks accounting for 120 m³ could be used as buffering volume in the new wastewater treatment plant. The operation of the referred plant is currently producing very good results with values below the specified limit of 5 Bq/l for the isotope 131 I. In addition, 90 Y has been reported to be eliminated at the same time. Over the past 2 years of operation, the wastewater treatment plant has been able to achieve a maximum processing capacity of more than 2,000 l/day, which equates to a nuclear medicine ward with approx. 20 beds. The highest level recorded during the test period (of 180 days after start-up) was a peak of nearly 2,800 l/day.
Mediastinal Parathyroid Adenoma and Brown Tumors
Authors: Bernal P. , Ucros G. , Mejia A.
Published: July 2012

In this report, we describe a rare case of brown tumor and mediastinal parathyroid adenoma. This report emphasizes the value of radionuclide scintigraphy in the setting of persistent disease following parathyroid surgery.
Asystole during posterior fossa surgery: Report of two cases
Authors: Goyal Keshav , Philip Frenny , Rath Girija , Mahajan Charu , Sujatha M , Bharti Sachidanand , Gupta Nidhi
Published: July 2012

Asystole during posterior fossa neurosurgical procedures is not uncommon. Various causes have been implicated, especially when surgical manipulation is carried out in the vicinity of the brain stem. The trigemino-cardiac reflex has been attributed as one of the causes. Here, we report two cases who suffered asystole during the resection of posterior fossa tumors. The vago-glossopharyngeal reflex and the direct stimulation of the brainstem were hypothesized as the causes of asytole. These episodes resolved spontaneously following withdrawal of the surgical stimulus emphasizing the importance of anticipation and vigilance during critical moments of tumor dissection during posterior fossa surgery.
Halogen activation via interactions with environmental ice and snow in the polar lower troposphere and other regions
Authors: Abbatt J. P. D. , Thomas J. L. , Abrahamsson K. , Boxe C. , Granfors A. , Jones A. E. , King M. D. , Saiz-Lopez A. , Shepson P. B. , Sodeau J. , Toohey D. W. , Toubin C. , von Glasow R. , Wren S. N. , Yang X.
Published: July 2012

Abstract. The role of ice in the formation of chemically active halogens in the environment requires a full understanding because of its role in atmospheric chemistry, including controlling the regional atmospheric oxidizing capacity in specific situations. In particular, ice and snow are important for facilitating multiphase oxidative chemistry and as media upon which marine algae live. This paper reviews the nature of environmental ice substrates that participate in halogen chemistry, describes the reactions that occur on such substrates, presents the field evidence for ice-mediated halogen activation, summarizes our best understanding of ice-halogen activation mechanisms, and describes the current state of modeling these processes at different scales. Given the rapid pace of developments in the field, this paper largely addresses advances made in the past five years, with emphasis given to the polar boundary layer. The integrative nature of this field is highlighted in the presentation of work from the molecular to the regional scale, with a focus on understanding fundamental processes. This is essential for developing realistic parameterizations and descriptions of these processes for inclusion in larger scale models that are used to determine their regional and global impacts.
Summertime weekly cycles of observed and modeled NOx and O3 concentrations as a function of satellite-derived ozone production sensitivity and land use types over the Continental United States
Authors: Choi Y. , Kim H. , Tong D. , Lee P.
Published: July 2012

Abstract. To show how remote-sensing products can be used to classify the entire CONUS domain into "geographical regions" and "chemical regimes", we analyzed the results of simulation from the Community Multiscale Air Quality (CMAQ) model version 4.7.1 over the Conterminous United States (CONUS) for August 2009. In addition, we observe how these classifications capture the weekly cycles of ground-level nitrogen oxide (NOx) and ozone (O3) at US EPA Air Quality System (AQS) sites. We use the Advanced Very High Resolution Radiometer (AVHRR) land use dominant categories and the Global Ozone Monitoring Experiment-2 (GOME-2) HCHO/NO2 column density ratios to allocate geographical regions (i.e., "urban", "forest", and "other" regions) and chemical regimes (i.e., "NOx-saturated", "NOx-sensitive", and "mixed" regimes). We also show that CMAQ simulations using GOME-2 satellite-adjusted NOx emissions mitigate the discrepancy between the weekly cycles of NOx from AQS observations and that from CMAQ simulation results. We found geographical regions and chemical regimes do not show a one-to-one correspondence: the averaged HCHO / NO2 ratios for AVHRR "urban" and "forest" regions are 2.1 and 4.0, which correspond to GOME-2 "mixed" and "NOx-sensitive" regimes, respectively. Both AQS-observed and CMAQ-simulated weekly cycles of NOx show high concentrations on weekdays and low concentrations on weekends, but with one- or two-day shifts of weekly high peaks in the simulated results, which eventually introduces the shifts in simulated weekly-low O3 concentration. In addition, whereas the high weekend O3 anomaly is clearly observable at sites over the GOME-2 NOx-saturated regime in both AQS and CMAQ, the weekend effect is not captured at sites over the AVHRR urban region because of the chemical characteristics of the urban sites (≈GOME-2 mixed regime). In addition, the weekend effect from AQS is more clearly discernible at sites above the GOME-2 NOx-saturated regime than at other sites above the CMAQ NOx-saturated regime, suggesting that the GOME-2-based chemical regime classification is more accurate than CMAQ-based chemical classification. Furthermore, the CMAQ simulations using the GOME-2-derived NOx emissions adjustment (decreasing from 462 Gg N to 426 Gg N over the US for August 2009) show large reductions of simulated NOx concentrations (particularly over the urban, or NOx-saturated, regime), and mitigates the large discrepancies between the absolute amount and the weekly pattern of NOx concentrations of the EPA AQS and those of the baseline CMAQ.
The importance of low-deformation vorticity in tropical cyclone formation
Authors: Tory K. J. , Dare R. A. , Davidson N. E. , McBride J. L. , Chand S. S.
Published: July 2012

Abstract. Studies of tropical cyclone (TC) formation from tropical waves have shown that TC formation requires a wave-relative quasi-closed circulation: the "marsupial pouch" concept. This results in a layerwise nearly contained region of atmosphere in which the modification of moisture, temperature and vorticity profiles by convective and boundary layer processes occurs undisturbed. The pouch concept is further developed in this paper. TCs develop near the centre of the pouch where the flow is in near solid body rotation. A reference-frame independent parameter is introduced that effectively measures the level of solid-body rotation in the lower troposphere. The parameter is the product of a normalized Okubo-Weiss parameter and absolute vorticity (OWZ). Using 20 yr of ERA-interim reanalysis data and the IBTrACS global TC database, it is shown 95% of TCs including, but not limited to, those forming in tropical waves are associated with enhanced levels of OWZ on both the 850 and 500 hPa pressure levels at the time of TC declaration, while 90% show enhanced OWZ for at least 24 h prior to declaration. This result prompts the question of whether the pouch concept extends beyond wave-type formation to all TC formations world-wide. Combining the OWZ with a low vertical shear requirement and lower troposphere relative humidity thresholds, an imminent genesis parameter is defined. The parameter includes only relatively large-scale fluid properties that are resolved by coarse grid model data (>150 km), which means it can be used as a TC detector for climate model applications. It is also useful as a cyclogenesis diagnostic in higher resolution models such as real-time global forecast models.
The sensitivity of stratospheric ozone changes through the 21st century to N2O and CH4
Authors: Revell L. E. , Bodeker G. E. , Huck P. E. , Williamson B. E. , Rozanov E.
Published: July 2012

Abstract. Through the 21st century, anthropogenic emissions of the greenhouse gases N2O and CH4 are projected to increase, thus increasing their atmospheric concentrations. Consequently, reactive nitrogen species produced from N2O and reactive hydrogen species produced from CH4 are expected to play an increasingly important role in determining stratospheric ozone concentrations. Eight chemistry-climate model simulations were performed to assess the sensitivity of stratospheric ozone to different emissions scenarios for N2O and CH4. Increases in reactive nitrogen-mediated ozone loss resulting from increasing N2O concentrations lead to a decrease in global-mean total column ozone. Increasing CH4 concentrations increase the rate of reactive hydrogen-mediated ozone loss in the upper stratosphere. Overall however, increasing CH4 concentrations lead to an increase in global-mean total column ozone. Stratospheric column ozone over the 21st century exhibits a near-linear response to changes in N2O and CH4 surface concentrations, which provides a simple parameterization for the ozone response to changes in these gases.
Lifetime and production rate of NOx in the upper stratosphere and lower mesosphere in the polar spring/summer after the solar proton event in October–November 2003
Authors: Friederich F. , von Clarmann T. , Funke B. , Nieder H. , Orphal J. , Sinnhuber M. , Stiller G. P. , Wissing J. M.
Published: July 2012

Abstract. We present altitude dependent lifetimes of NOx, determined with MIPAS/ENVISAT, for the southern polar region after the solar proton event in October–November 2003. Varying in latitude and decreasing in altitude they range from about two days at 64 km to about 20 days at 44 km. The lifetimes are controlled by transport, mixing and photolysis. We infer dynamical lifetimes by comparison of the observed decay to photolytical lifetimes calculated with the SLIMCAT 3-D Model. Photochemical loss contributes to the observed NOx depletion by 10% at 44 km, increasing with altitude to 35% at 62 km at a latitude of –63° S. At higher latitudes, the contribution of photochemical loss can be even more important. In addition, we show the correlation of modeled ionization rates and observed NOx densities under consideration of the determined lifetimes of NOx, and calculate altitude dependent effective production rates of NOx due to ionization. For that we compare ionization rates of the AIMOS data base with the MIPAS measurements for the whole Austral polar summer 2003/04. We derive effective NOx-production rates to be applied to the AIMOS ionization rates which range from about 0.2 NOx-molecules per ion pair at 44 km to 0.9 NOx-molecules per ion pair at 54 km at a latitude of –63° S. At –73° S, the NOx-production rate ranges from about 0.2 NOx-molecules per ion pair at 44 km to 1.0 NOx-molecules per ion pair at 60 km. These effective production rates are considerably lower than predicted by box model simulations which could hint at an overestimation of the modeled ionization rates.
How well do different tracers constrain the firn diffusivity profile?
Authors: Trudinger C. M. , Enting I. G. , Rayner P. J. , Etheridge D. M. , Buizert C. , Rubino M. , Krummel P. B. , Blunier T.
Published: July 2012

Abstract. Firn air transport models are used to interpret measurements of the composition of air in firn and bubbles trapped in ice in order to reconstruct past atmospheric composition. The diffusivity profile in the firn is usually calibrated by comparing modelled and measured concentrations for tracers with known atmospheric history. However, in some cases this is an under-determined inverse problem, often with multiple solutions giving an adequate fit to the data (this is known as equifinality). Here we describe a method to estimate the firn diffusivity profile that allows multiple solutions to be identified, in order to quantify the uncertainty in diffusivity due to equifinality. We then look at how well different combinations of tracers constrain the firn diffusivity profile. Tracers with rapid atmospheric variations like CH3CCl3, HFCs and 14CO2 are most useful for constraining molecular diffusivity, while δ15N2 is useful for constraining parameters related to convective mixing near the surface. When errors in the observations are small and Gaussian, three carefully selected tracers are able to constrain the molecular diffusivity profile well with minimal equifinality. However, with realistic data errors or additional processes to constrain, there is benefit to including as many tracers as possible to reduce the uncertainties. We calculate CO2 age distributions and their spectral widths with uncertainties for five firn sites (NEEM, DE08-2, DSSW20K, South Pole 1995 and South Pole 2001) with quite different characteristics and tracers available for calibration. We recommend moving away from the use of a single firn model with one calibrated parameter set to infer atmospheric histories, and instead suggest using multiple parameter sets, preferably with multiple representations of uncertain processes, to allow quantification of the uncertainties.
Thermodynamics of reactions of ClHg and BrHg radicals with atmospherically abundant free radicals
Authors: Dibble T. S. , Zelie M. J. , Mao H.
Published: July 2012

Abstract. Quantum calculations are used to determine the stability of reactive gaseous mercury (Hg(II)) compounds likely to be formed in the Br-initiated oxidation of gaseous elemental mercury (Hg(0)). Due to the absence of any evidence, current models neglect the possible reaction of BrHg• with abundant radicals such as NO, NO2, HO2, ClO, or BrO. The present work demonstrates that BrHg• forms stable compounds, BrHgY, with all of these radicals except NO. Additional calculations on the analogous ClHgY compounds reveal that the strength of the XHg-Y bond (for X=Cl, Br) varies little with the identity of the halogen. Calculations further suggest that ClO, BrO, and NO3 do not form strong bonds with Hg(0), and cannot initiate Hg(0) oxidation in the gas phase. The theoretical approach is validated by comparison to published data on HgX2 compounds, both from experiments and highly refined quantum chemical calculations. Quantum calculations on the stability of the anions of XHgY are carried out in order to aid future laboratory studies aimed at molecular-level characterization of gaseous Hg(II) compounds. Spectroscopic data on BrHg• are analyzed to determine the equilibrium constant for its formation, and BrHg• is determined to be much less stable than previously estimated. An expression is presented for the rate constant for BrHg• dissociation.
Contrasting trends of mass and optical properties of aerosols over the Northern Hemisphere from 1992 to 2011
Authors: Wang K. , Dickinson R. E. , Su L. , Trenberth K. E.
Published: July 2012

Abstract. Atmospheric aerosols impact both human health and climate. PMX is the mass concentration of aerosol particles that have aerodynamic diameters less than X μm, PM10 was initially selected to measure the environmental impact of aerosols. Recently, it was realized that fine particles are more hazardous than larger ones and should be measured. Consequently, observational data for PM2.5 have been obtained but only for a much shorter period than that of PM10. Optical extinction of aerosols, the inverse of meteorological visibility, is sensitive to particles less than 1.0 μm. These fine particles only account for a small part of total mass of aerosols although they are very efficient in light extinction. Comparisons are made between PM10 and PM2.5 over the period when the latter is available and with visibility data for a longer period. PM10 has decreased by 44% in Europe from 1992 to 2009, 33% in the US from 1993 to 2010, 10% in Canada from 1994 to 2009, and 26% in China from 2000 to 2010. However, in contrast, aerosol optical extinction increased 7% in the US, 10% in Canada, and 18% in China during the above study periods. The reduction of optical extinction over Europe of 5% is also much less than the 44% reduction in PM10. Over its short period of record PM2.5 decreased less than PM10. Hence, PM10 is neither a good measure of changes in smaller particles or of their long-term trends, a result that has important implications for both climate impact and human health effects. The increased fraction of anthropogenic aerosol emission, such as vehicle exhaust, to total atmospheric aerosols partly explains this contrasting trend of optical and mass properties of aerosols.
Eyjafjallajökull volcano plume particle-type characterization from space-based multi-angle imaging
Authors: Kahn R. A. , Limbacher J.
Published: July 2012

Abstract. The Multi-angle Imaging SpectroRadiometer (MISR) Research Aerosol algorithm makes it possible to study individual aerosol plumes in considerable detail. From the MISR data for two optically thick, near-source plumes from the spring 2010 eruption of the Eyjafjallajökull volcano, we map aerosol optical depth (AOD) gradients and changing aerosol particle types with this algorithm; several days downwind, we identify the occurrence of volcanic ash particles and retrieve AOD, demonstrating the extent and the limits of ash detection and mapping capability with the multi-angle, multi-spectral imaging data. Retrieved volcanic plume AOD and particle microphysical properties are distinct from background values near-source, as well as for over-water cases several days downwind. The results also provide some indication that as they evolve, plume particles brighten, and average particle size decreases. Such detailed mapping offers context for suborbital plume observations having much more limited sampling. The MISR Standard aerosol product identified similar trends in plume properties as the research algorithm, though with much smaller differences compared to background, and it does not resolve plume structure. Better optical analogs of non-spherical volcanic ash, and coincident suborbital data to validate the satellite retrieval results, are the factors most important for further advancing the remote sensing of volcanic ash plumes from space.
Seasonal cycles of biogenic volatile organic compound fluxes and concentrations in a California citrus orchard
Authors: Fares S. , Park J.-H. , Gentner D. R. , Weber R. , Ormeño E. , Karlik J. , Goldstein A. H.
Published: July 2012

Abstract. Orange trees are widely cultivated in Mediterranean climatic regions where they are an important agricultural crop. Citrus have been characterized as emitters of volatile organic compounds (VOC) in chamber studies under controlled environmental conditions, but an extensive characterization at field scale has never been performed using modern measurement methods, and is particularly needed considering the complex interactions between the orchards and the polluted atmosphere in which Citrus is often cultivated. For one year, in a Valencia orange orchard in Exeter, California, we measured fluxes using PTRMS (Proton Transfer Reaction Mass Spectrometer) and eddy covariance for the most abundant VOC typically emitted from citrus vegetation: methanol, acetone, and isoprenoids. Concentration gradients of additional oxygenated and aromatic compounds from the ground level to above the canopy were also measured. In order to characterize concentrations of speciated biogenic VOC (BVOC) in leaves, we analyzed leaf content by GC-MS (Gas Chromatography-Mass Spectrometery) regularly throughout the year. We also characterize in more detail concentrations of speciated BVOC in the air above the orchard by in-situ GC-MS during a few weeks in spring flowering and summer periods. Here we report concentrations and fluxes of the main VOC species emitted by the orchard, discuss how fluxes measured in the field relate to previous studies made with plant enclosures, and describe how VOC content in leaves and emissions change during the year in response to phenological and environmental parameters. The orchard was a source of monoterpenes and oxygenated VOC. The highest emissions were observed during the springtime flowering period, with mid-day fluxes above 2 nmol m−2 s−1 for methanol and up to 1 nmol m−2 s−1 for acetone and monoterpenes. During hot summer days emissions were not as high as we expected considering the known dependence of biogenic emissions on temperature. We provide evidence that thickening of leaf cuticle wax content limited gaseous emissions during the summer.
Use of geomorphic, hydrologic, and nitrogen mass balance data to model ecosystem nitrate retention in tidal freshwater wetlands
Authors: Seldomridge E. D. , Prestegaard K. L.
Published: July 2012

Abstract. Geomorphic characteristics have been used as scaling parameters to predict water and other fluxes in many systems. In this study, we combined geomorphic analysis with in-situ mass balance studies of nitrate retention (NR) to evaluate which geomorphic scaling parameters best predicted NR in a tidal freshwater wetland ecosystem. Geomorphic characteristics were measured for 267 individual marshes that constitute the freshwater tidal wetland ecosystem of the Patuxent River, Maryland. Nitrate retention was determined from mass balance measurements conducted at the inlets of marshes of varying size (671, 5705, and 536 873 m2) over a period of several years. Mass balance measurements indicate that NR is proportional to total water flux over the tidal cycle. Relationships between estimated tidal prism (calculated water volume) for spring tides and various geomorphic parameters (marsh area, total channel length, and inlet width) were defined using measurements from air photos and compared to field data. From these data, NR equations were determined for each geomorphic parameter, and used to estimate NR for all marshes in the ecosystem for a reference spring (high) tide. The resulting ecosystem NR estimates were evaluated for (a) accuracy and completeness of geomorphic data, (b) relationship between the geomorphic parameters and hydrologic flux, and (c) the ability to adapt the geomorphic parameter to varying tidal conditions. This analysis indicated that inlet width data were the most complete and provided the best estimate of ecosystem nitrate retention. Predictions based on marsh area were significantly lower than the inlet width-based predictions. Cumulative probability distributions of nitrate retention indicate that the largest 3–4% of the marshes retained half of the total nitrate for the ecosystem.
Impact of an extremely large magnitude volcanic eruption on the global climate and carbon cycle estimated from ensemble Earth System Model simulations
Authors: Segschneider J. , Beitsch A. , Timmreck C. , Brovkin V. , Ilyina T. , Jungclaus J. , Lorenz S. J. , Six K. D. , Zanchettin D.
Published: July 2012

Abstract. The response of the global climate-carbon cycle system to an extremely large Northern Hemisphere mid latitude volcanic eruption is investigated using ensemble integrations with the comprehensive Earth System Model MPI-ESM. The model includes dynamical compartments of the atmosphere and ocean and interactive modules of the terrestrial biosphere as well as ocean biogeochemistry. The MPI-ESM was forced with anomalies of aerosol optical depth and effective radius of aerosol particles corresponding to a super eruption of the Yellowstone volcanic system. The model experiment consists of an ensemble of fifteen model integrations that are started at different pre-ENSO states of a contol experiment and run for 200 yr after the volcanic eruption. The climate response to the volcanic eruption is a maximum global monthly mean surface air temperature cooling of 3.8 K for the ensemble mean and from 3.3 K to 4.3 K for individual ensemble members. Atmospheric pCO2 decreases by a maximum of 5 ppm for the ensemble mean and by 3 ppm to 7 ppm for individual ensemble members approximately 6 yr after the eruption. The atmospheric carbon content only very slowly returns to near pre-eruption level at year 200 after the eruption. The ocean takes up carbon shortly after the eruption in response to the cooling, changed wind fields, and ice cover. This physics driven uptake is weakly counteracted by a reduction of the biological export production mainly in the tropical Pacific. The land vegetation pool shows a distinct loss of carbon in the initial years after the eruption which has not been present in simulations of smaller scale eruptions. The gain of the soil carbon pool determines the amplitude of the CO2 perturbation and the long term behaviour of the overall system: an initial gain caused by reduced soil respiration is followed by a rather slow return towards pre-eruption levels. During this phase, the ocean compensates partly for the reduced atmospheric carbon content in response to the land's gain. In summary, we find that the volcanic eruption has long lasting effects on the carbon cycle: after 200 yr, the ocean and the land carbon pools are still different from the pre-eruption state, and the land carbon pools (vegetation and soil) show some long lasting local anomalies that are only partly visible in the global signal.
Does Antarctic glaciation cool the world?
Authors: Goldner A. , Huber M. , Caballero R.
Published: July 2012

Abstract. In this study we compare the simulated climatic impact of adding the Antarctic Ice Sheet to the "Greenhouse World" of the Eocene and removing the Antarctic Ice Sheet from the Modern world. The Modern surface temperature anomaly (ΔT) induced by Antarctic Glaciation ranges from −1.22 to −0.18 K when CO2 is dropped from 2240 to 560 ppm, whereas the Eocene ΔT is nearly constant at −0.3 K. We calculate the climate sensitivity parameter S[Antarctica] which is defined as the change in surface temperature (ΔT) divided by the change in radiative forcing (ΔQAntarctica) imposed by prescribing the glacial properties of Antarctica. While the ΔT associated with the imposed Antarctic properties is relatively consistent across the Eocene cases, the radiative forcing is not. This leads to a wide range of S[Antarctica], with Eocene values systematically smaller than Modern. This differing temperature response in Eocene and Modern is partially due to the smaller surface area of the imposed forcing over Antarctica in the Eocene and partially due to the presence of strong positive sea-ice feedbacks in the Modern. The system's response is further mediated by differing shortwave cloud feedbacks which are large and of opposite sign operating in Modern and Eocene configurations. A negative cloud feedback warms much of the Earth's surface as a large ice sheet is introduced in Antarctica in the Eocene, whereas in the Modern this cloud feedback is positive and acts to enhance cooling introduced by adding an ice sheet. Because of the importance of cloud feedbacks in determining the final temperature sensitivity of the Antarctic Ice Sheet our results are likely to be model dependent. Nevertheless, these model results show that the radiative forcing and feedbacks induced by the Antarctic Ice Sheet did not significantly decrease global mean surface temperature across the Eocene-Oligocene transition (EOT) and that other factors like declining atmospheric CO2 are more important for cooling across the EOT. The results indicate that climate transitions associated with glaciation depend on the climate background state. This means that using paleoclimate proxy data by itself, from the EOT to estimate Earth System Sensitivity, into the future, is made difficult without relying on climate models and consequently these modelling estimates will have large uncertainty, largely due to low clouds.
Effects of land cover change on temperature and rainfall extremes in multi-model ensemble simulations
Authors: Pitman A. J. , de Noblet-Ducoudré N. , Avila F. B. , Alexander L. V. , Boisier J.-P. , Brovkin V. , Delire C. , Cruz F. , Donat M. G. , Gayler V. , van den Hurk B. , Reick C. , Voldoire A.
Published: July 2012

Abstract. The impact of historical land use induced land cover change (LULCC) on regional-scale climate extremes is examined using four climate models within the Land Use and Climate, IDentification of robust impacts project. To assess those impacts, multiple indices based on daily maximum and minimum temperatures and daily precipitation were used. We contrast the impact of LULCC on extremes with the impact of an increase in atmospheric CO2 from 280 ppmv to 375 ppmv. In general, changes in both high and low temperature extremes are similar to the simulated change in mean temperature caused by LULCC and are restricted to regions of intense modification. The impact of LULCC on both means and on most temperature extremes is statistically significant. While the magnitude of the LULCC induced change in the extremes can be of similar magnitude to the response to the change in CO2, the impacts of LULCC are much more geographically isolated. For most models the impacts of LULCC oppose the impact of the increase in CO2 except for one model where the CO2-caused changes in the extremes is amplified. While we find some evidence that individual models respond consistently to LULCC in the simulation of changes in rainfall and rainfall extremes, LULCC's role in affecting rainfall is much less clear and less commonly statistically significant, with the exception of a consistent impact over South East Asia. Since the simulated response of mean and extreme temperature to LULCC is relatively large, we conclude that unless this forcing is included we risk erroneous conclusions regarding the drivers of temperature changes over regions of intense LULCC.
Pliocene Ice Sheet Modelling Intercomparison Project (PLISMIP) – experimental design
Authors: Dolan A. M. , Koenig S. J. , Hill D. J. , Haywood A. M. , DeConto R. M.
Published: July 2012

Abstract. During the mid-Pliocene warm period (3.264 to 3.025 million years ago), global mean temperature was similar to that predicted for the next century and atmospheric carbon dioxide concentrations were slightly higher than today. Sea level was also higher than today, implying a reduction in the extent of the ice sheets. Thus, the mid-Pliocene warm period (mPWP) provides a unique testing ground to investigate the stability of the Earth's ice sheets and their contribution to sea level in a warmer-than-modern world. Climate models and ice sheet models can be used to enhance our understanding of ice sheet stability; however, uncertainties associated with different ice-sheet modelling frameworks mean that a rigorous comparison of numerical ice sheet model simulations for the Pliocene is essential. As an extension to the Pliocene Model Intercomparison Project (PlioMIP; Haywood et al., 2010, 2011a), the Pliocene Ice Sheet Modelling Intercomparison Project (PLISMIP) will provide the first assessment as to the ice sheet model dependency of ice sheet predictions for the mPWP. Here we outline the PLISMIP experimental design and initialisation conditions that have been adopted to simulate the Greenland and Antarctic ice sheets under present-day and warm mid-Pliocene conditions. Not only will this project provide a new benchmark in the simulation of ice sheets in a past warm period, but the analysis of model sensitivity to various uncertainties could directly inform future predictions of ice sheet and sea level change.
Teaching hydrogeology: a review of current practice
Authors: Gleeson T. , Allen D. M. , Ferguson G.
Published: July 2012

Abstract. Hydrogeology is now taught in a broad spectrum of departments and institutions to students with diverse backgrounds. Successful instruction in hydrogeology thus requires a variety of pedagogical approaches depending on desired learning outcomes and the background of students. We review the pedagogical literature in hydrogeology to highlight recent advances and analyze a 2005 survey among 68 hydrogeology instructors. The literature and survey results suggest there are only ~ 15 topics that are considered crucial by most hydrogeologists and > 100 other topics that are considered crucial by some hydrogeologists. The crucial topics focus on properties of aquifers and fundamentals of groundwater flow, and should likely be part of all undergraduate hydrogeology courses. Other topics can supplement and support these crucial topics, depending on desired learning outcomes. Classroom settings continue to provide a venue for emphasizing fundamental knowledge. However, recent pedagogical advances are biased towards field and laboratory instruction with a goal of bolstering experiential learning. Field methods build on the fundamentals taught in the classroom and emphasize the collection of data, data uncertainty, and the development of vocational skills. Laboratory and computer-based exercises similarly build on theory, and offer an opportunity for data analysis and integration. The literature suggests curricula at all levels should ideally balance field, laboratory, and classroom pedagogy into an iterative and integrative whole. An integrated, iterative and balanced approach leads to greater student motivation and advancement of theoretical and vocational knowledge.
Brief communication "An auto-diagnosis tool to highlight interdependencies between urban technical networks"
Authors: Toubin M. , Serre D. , Diab Y. , Laganier R.
Published: July 2012

Abstract. Natural hazards threaten the urban system and its components that are likely to fail. With their high degree of interdependency, urban networks and services are critical issues for the resilience of a city. And yet, network managers are scarcely aware of their flaws and dependencies and they are reluctant to take them into account. In order to develop an operational tool to improve urban resilience, we propose here an auto-diagnosis method to be completed by network managers. The subsequent confrontation of all diagnoses is the basis of collaborative research for problem identification and solution design. The tool is experimented with the Parisian urban transport society.
Strengths and strain energies of volcanic edifices: implications for eruptions, collapse calderas, and landslides
Authors: Gudmundsson A.
Published: July 2012

Abstract. Natural hazards associated with volcanic edifices depend partly on how fracture resistant the edifices are, i.e. on their strengths. Observations worldwide indicate that large fluid-driven extension fractures (dikes, inclined sheets), shear fractures (landslides), and mixed-mode fractures (ring dikes and ring faults) normally propagate more easily in a basaltic edifice (shield volcano) than in a stratovolcano. For example, dike-fed eruptions occur once every few years in many basaltic edifices but once every 102-3 yr in many stratovolcanoes. Large landslides and caldera collapses also appear to be more common in a typical basaltic edifice/shield volcano than in a typical stratovolcano. In contrast to a basaltic edifice, a stratovolcano is composed of mechanically dissimilar rock layers, i.e. layers with mismatching elastic properties (primarily Young's modulus). Elastic mismatch encourages fracture deflection and arrest at contacts and increases the amount of energy needed for a large-scale edifice failure. Fracture-related hazards depend on the potential energy available to propagate the fractures which, in turn, depends on the boundary conditions during fracture propagation. Here there are two possible scenarios: one in which the outer boundary of the volcanic edifice or rift zone does not move during the fracture propagation (constant displacement); the other in which the boundary moves (constant load). In the former, the total potential energy is the strain energy stored in the volcano before fracture formation; in the latter, the total potential energy is the strain energy plus the work done by the forces moving the boundary. Constant-displacement boundary conditions favor small eruptions, landslides, and caldera collapses, whereas constant-load conditions favor comparatively large eruptions, landslides, and collapses. For a typical magma chamber (sill-like with a diameter of 8 km), the strain energy change due to magma-chamber inflation is estimated at the order of 1014 J (0.1 PJ). For comparison, the surface energy needed to form a typical feeder dike is of the same order of magnitude, or 1014 J. There are several processes besides magma-chamber inflation that may increase the strain energy in a volcano before eruption. Thus, during a typical unrest period with magma-chamber inflation, the added strain energy in the volcano is large enough for a typical feeder dike to form. An injected dike, however, only reaches the surface and becomes a feeder if it is able to propagate through the numerous layers and contacts that tend to deflect or arrest dikes. The strong elastic mismatch between layers that constitute stratovolcanoes not only encourages fracture arrest, but also the storage of more strain energy (than in a typical basaltic edifice/shield volcano) before fracture formation and failure. It is thus through producing materials of widely different mechanical properties that stratovolcanoes become strong and resilient.
Atlantic transport variability at 25° N in six hydrographic sections
Authors: Atkinson C. P. , Bryden H. L. , Cunningham S. A. , King B. A.
Published: July 2012

Abstract. In January and February 2010, a sixth transatlantic hydrographic section was completed across 25° N, extending the hydrographic record at this latitude to over half a century. In combination with continuous transport measurements made since 2004 at 26.5° N by the Rapid-WATCH project, we reassess transport variability in the 25° N hydrographic record. Past studies of transport variability at this latitude have assumed transport estimates from each hydrographic section to represent annual average conditions. In this study the uncertainty in this assumption is assessed through use of Rapid-WATCH observations to quantify sub-seasonal and seasonal transport variability. Whilst in the upper-ocean no significant interannual or decadal transport variability are identified in the hydrographic record, in the deep ocean transport variability in both depth and potential temperature classes suggests some interannual or decadal variability may have occurred. This is particularly striking in the lower North Atlantic Deep Water where southward transports prior to 1998 were greater than recent transports by several Sverdrups. Whilst a cooling and freshening of Denmark Straits Overflow Water has occurred which is coincident with these transport changes, these water mass changes appear to be density compensated. Transport changes are the result of changing velocity shear in the vicinity of the Deep Western Boundary Current.
Selection of Clinically useful Angiogenesis-Related Biomarkers: An Update
Authors: Todorovic-Raković NatašA , Vujasinović Tijana , Rabi Zaki Abu
Published: July 2012

Angiogenesis is a complex phenomenon that involves interaction between growth factors/cytokines and their receptors, and proteolytic enzymes and their inhibitors, which, in addition to and in accordance with their main roles, act together during this multistep process. cancer angiogenesis is specific, because the same factors that enable angiogenesis are involved in the process of carcinogenesis. the aim of this review was to analyze the current knowledge regarding the significance of selected biomarkers in cancer angiogenesis, with emphasis on their prognostic value in the circulation.
¿Cambian sus preferencias los participantes en la deliberación?
Authors: Ganuza Fernández Ernesto , Francés García Francisco José , Lafuente Fernández Regina , Garrido Fernando
Published: July 2012

El objetivo de este trabajo es analizar el cambio de opinión de losparticipantes en un foro deliberativo. Su contribución reside en estudiarhasta qué punto esos cambios perduran en el tiempo. Partiremos dela hipótesis de Mackie que sostiene que los cambios de opinión en uncontexto deliberativo no pueden ser interpretados considerando variablesde forma aislada, sino que deben basarse en la red actitudinal delos individuos de la que emergen sus preferencias. Los resultados nosmuestran que algunos cambios no se mantienen tiempo después de ladeliberación entre algunos individuos. El trabajo detalla la importanciaque adquieren determinadas variables en el cambio de opinión a corto ya largo plazo, así como la interrelación que se da entre diferentes actitudesen tres momentos distintos antes y después de la deliberación.
Transición territorial: modelo teórico y contraste con el caso español
Authors: Docampo Garcia Manuel , Otero-Enríquez Raimundo
Published: July 2012

Analizando conjuntamente los fl ujos de éxodo rural, concentración ydesconcentración urbana, en un mismo sistema comprensivo, podemosencontrar unas lógicas de asentamiento características de cada momentosocioeconómico. Este artículo es un intento por sintetizar esas pautas, quedan lugar a cambios de protagonismo en las dinámicas territoriales entrediferentes hábitats y en las tipologías migratorias que se suceden en eltiempo. Denominamos transición territorial al modelo resultante. Aunquetiene un entronque teórico con importantes precedentes, puede considerarseeste como una aportación original, en tanto no existen formulaciones tanexplícitas y detalladas del mismo. La secuencia expositiva tiene dos partes:se comienza presentando los fundamentos, antecedentes teóricos y fasesde la transición territorial; continúa con un contraste con la realidad observadaen el caso español, analizando en detalle algunas particularidadesrelevantes. Subrayamos, como conclusión, que la formulación de estemodelo puede permitir la interpretación de fenómenos aparentementeconfusos o contrapuestos de otros sistemas territoriales internacionales.