bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature‐induced stress leads to bleaching in larger benthic foraminifera hosting endosymbiotic diatoms
Authors: Schmidt Christiane , Heinz Petra , Kucera Michal , Uthicke Sven
Published: July 2011

Physiological mechanisms of bleaching were studied on larger benthic foraminifera (LBF) hosting endosymbiotic diatoms. Amphistegina radiata, Heterostegina depressa, and Calcarina hispida were exposed to increasing temperatures in static temperature experiments (23°C to 33°C, 6 d). Photosynthetic activity (Fv : Fm, measured with a pulse‐amplitude modulated fluorometer), chlorophyll a (a proxy for symbiont biomass), and motility (a proxy for overall fitness of the foraminifera) were reduced in specimens at 32°C to 33°C, and cytoplasm color changes associated with bleaching were observed. A 30‐d flow‐through experiment at three temperatures (26°C to 31°C) and three levels of inorganic nitrate concentration (0.5 to 1.4 µmol L−1) confirmed negative effects of temperature at 31°C for A. radiata (including growth) and H. depressa. Another Calcarina species, Calcarina mayorii, was not affected. This suggests that temperature effects are species‐specific. However, elevated nutrient concentrations did not affect any of the parameters measured. Temperatures > 30°C stress the foram–diatom endosymbiosis in some LBF species, which may lead to subsequent bleaching of the host. Given that a 2–3°C increase led to rapid bleaching of most species, we propose that, similar to corals, these species are threatened by sea‐surface temperature increase predicted for tropical reef waters in the near future.
Community dynamics over 14 years at the Eiffel Tower hydrothermal edifice on the Mid‐Atlantic Ridge
Authors: Cuvelier Daphne , Sarrazin Jozée , Colaço Ana , Copley Jon T. , Glover Adrian G. , Tyler Paul A. , Santos Ricardo Serrão , Desbruyères Daniel
Published: July 2011

The Lucky Strike hydrothermal vent field, situated on the Mid‐Atlantic Ridge (MAR), has been visited on a regular basis since 1992. The video imagery analyzed in this study originated from 10 cruises and was acquired either with the Nautile submersible or with the Remotely Operated Vehicle Victor 6000 between 1994 and 2008. Four faunal assemblages and two substratum types were identified on a large mussel‐dominated sulfide edifice named “Eiffel Tower.” Their dynamics over 14 yr were investigated both at the scale of the entire edifice, between the edifice sides, and at small patch scales, making this the first high‐time‐resolution long‐term variations study on the MAR. Overall percentage of biological colonization and overall mussel coverage were stable on a decadal scale. However, on shorter time scales as well as on smaller spatial scales, significant differences in microbial cover and in individual assemblage coverage and distribution were observed. The small fluctuations in the rather constant overall percentage of colonization (~ 50%) were explained by subtle changes in hydrothermal activity, which showed a significant negative correlation. However, not all variations occurring in the community structure could be explained by the hydrothermal activity, whereas the orientation of the edifice appeared to play an important role. We proposed a succession model for the shallower MAR fields, in addition to the first quantification of the rate of change in community dynamics at this slow‐spreading ridge. This rate of change appeared to be about 15% slower than that observed on sulfide edifices from faster‐spreading ridges in the Northeast Pacific.
Vertical migrations of reef fish larvae in the Straits of Florida and effects on larval transport
Authors: Huebert Klaus B. , Cowen Robert K. , Sponaugle Su
Published: July 2011

The goals of this study were to measure vertical distributions of pelagic coral reef fish larvae, identify significant vertical migrations, and estimate the effects of vertical migrations between depths with different ambient currents on larval transport in the Straits of Florida. Spring, summer, and fall time‐series of plankton net tows were conducted at the edge of the Florida Current offshore of Miami. In each time‐series the upper 100 m of the water column at a fixed station was sampled repeatedly at 3‐h intervals for two diel cycles, with different nets sampling at five discrete depth ranges. Simultaneously, currents‐at‐depth were recorded by shipboard current profilers. Mean and standard deviation of larval depth and statistically significant vertical migrations were determined by nonparametric resampling and tree regression techniques. In 10 taxa, larvae showed ontogenic vertical migrations, gradually moving deeper with growth and development. Vertical distributions of six taxa varied between day and night, revealing diel vertical migrations. Larval transport was estimated by generating progressive vector diagrams from current measurements and larval vertical distributions. The dominant alongshore component of the Florida Current resulted in rapid larval transport through the Straits of Florida, while cross‐shore current was an order of magnitude weaker and highly variable. Larvae at depths > 70 m experienced a 15–75% reduction in transport; thus, deep vertical distributions and downward vertical migrations potentially favor retention and settlement in the Straits of Florida.
Experimental evidence of a low‐oxygen refuge for large zooplankton
Authors: Larsson Petter , Lampert Winfried
Published: July 2011

We tested the hypothesis that hypoxic zones in the metalimnion and hypolimnion of lakes can provide a refuge against fish predation for large zooplankton. Experiments were run in a large indoor mesocosm system (Plön Plankton Towers). We compared mortality rates of Daphnia pulicaria due to free‐ranging fish in mesocosms with either oxic or hypoxic hypolimnia. In the presence of fish Daphnia moved down below the thermocline. Under hypoxic conditions their distribution peaked in the upper hypolimnion at a concentration of approximately 1 mg O2 L−1. In oxygen‐saturated hypolimnia Daphnia were distributed evenly. The mortality rate of Daphnia in the hypoxic treatment was only one third of that in the oxic treatment. The hypoxic habitat provided a refuge, as Daphnia tolerated lower oxygen concentrations than did fish. However, there may be demographic costs associated with living in low‐oxygen conditions. Hence, the importance of a hypoxic refuge under natural conditions will most likely depend on the trade‐off between predation risk and cost of living in hypoxic waters.
Stress Corrosion Cracking of Sensitized 304 Austenitic Stainless Steel in Petroleum Refinery Environment
Authors: Ahmad S. , Mehta M. L. , Saraf S. K. , Saraswat I. P.
Published: July 2011

Stress corrosion cracking (SCC) investigations of sensitized 304 austenitic stainless steel were conducted using U-bend specimens of 6.45 and 12.85 mm radii of curvature in Samans solution, which represents the polythionic acid solution formed in the petroleum refineries during shutdown as a result of the interaction of the sulfide scale on the steel surface with moisture and oxygen at ambient temperatures. The chemical analysis of the Samans solution revealed that it contained seven different constituents varying in concentration. They are sulfuric, sulfurous, and thionic acids (di-, tri-, tetra-, penta-, and hexathionic acid). The role of each individual constituent of Samans solution on SCC has been studied. The results of the chemical analysis of the test solutions after failure revealed that out of all constituents of the Samans solution, only tetrathionic acid induced stress corrosion failure of sensitized 304 austenitic stainless steel. The metallographic studies of the fractured surfaces conducted by SEM revealed intercrystalline mode of fracture in all the cases in which the samples cracked.
The MIPAS HOCl climatology
Authors: von Clarmann T. , Funke B. , Glatthor N. , Kellmann S. , Kiefer M. , Kirner O. , Sinnhuber B.-M. , Stiller G. P.
Published: July 2011

Abstract. Monthly zonal mean HOCl measurements by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) are presented for the episode from June 2002 to March 2004. Highest molar mixing ratios are found at pressure levels between 6 and 2 hPa, whereby largest mixing ratios occasionally exceed 200 ppt. The mixing ratio maximum is generally at lower altitudes in the summer hemisphere than in the winter hemisphere except for chlorine activation conditions in polar vortices, where enhanced HOCl abundances are also found in the lower stratosphere. During nighttime the maximum is found at higher altitudes than during daytime. Particularly low values are found in subpolar regions in the winter hemisphere, coinciding with the mixing barrier formed by the polar vortex boundary. The Antarctic polar winter HOCl distribution in 2002, the year of the split of the southern polar vortex, resembles northern polar winters rather than other southern polar winters. Increased HOCl amounts in response to the so-called Halloween solar proton event in autumn 2003 affect the representativeness of data recorded during this particular episode. Calculations with the EMAC model reproduce the structure of the measured HOCl distribution but predict approximately 40 % less HOCl except during polar night in the mid-stratosphere where calculated HOCl mixing ratios exceed observed ones.
The role of carbonyl sulphide as a source of stratospheric sulphate aerosol and its impact on climate
Authors: Brühl C. , Lelieveld J. , Crutzen P. J. , Tost H.
Published: July 2011

Abstract. Globally, carbonyl sulphide (COS) is the most abundant sulphur gas in the atmosphere. Our chemistry-climate model of the lower and middle atmosphere with aerosol module realistically simulates the background stratospheric sulphur cycle, as observed by satellites in volcanically quiescent periods. The model results indicate that upward transport of COS from the troposphere largely controls the sulphur budget and the aerosol loading of the background stratosphere. This differs from most previous studies which indicated that short-lived sulphur gases are also important. The model realistically simulates the modulation of the particulate and gaseous sulphur abundance in the stratosphere by the quasi-biennial oscillation (QBO). In the lowermost stratosphere organic carbon aerosol contributes significantly to extinction. Further, we compute that the radiative forcing efficiency by 1 kg of COS is 724 times that of 1 kg CO2, which translates into an overall radiative forcing by anthropogenic COS of 0.003 W m−2. The global warming potentials of COS over time horizons of 20 and 100 yr are GWP(20 yr) = 97 and GWP(100 yr) = 27, respectively (by mass). Furthermore, stratospheric aerosol particles produced by the photolysis of COS contribute to a negative radiative forcing, which amounts to −0.007 W m−2 at the top of the atmosphere for the anthropogenic fraction, more than two times the warming forcing of COS. Considering that the lifetime of COS is twice that of stratospheric aerosols the warming and cooling tendencies approximately cancel. If the forcing of the troposphere near the tropopause is considered, the cooling dominates.
Constraining the CO2 budget of the corn belt: exploring uncertainties from the assumptions in a mesoscale inverse system
Authors: Lauvaux T. , Schuh A. E. , Uliasz M. , Richardson S. , Miles N. , Andrews A. E. , Sweeney C. , Diaz L. I. , Martins D. , Shepson P. B. , Davis K. J.
Published: July 2011

Abstract. We performed an atmospheric inversion of the CO2 fluxes over Iowa and the surrounding states, from June to December 2007, at 20 km resolution and weekly timescale. Eight concentration towers were used to constrain the carbon balance in a 1000 × 1000 km2 domain in this agricultural region of the US upper midwest. The CO2 concentrations of the boundaries derived from CarbonTracker were adjusted to match direct observations from aircraft profiles around the domain. The regional carbon balance ends up with a sink of 178 TgC±35 TgC over the area for the period June–December, 2007. Potential bias from incorrect boundary conditions of about 0.4 ppm over the 7 months was corrected using mixing ratios from four different aircraft profile sites operated at a weekly time scale, acting as an additional source of uncertainty of 18 TgC. We used two different prior flux estimates, the SiBCrop model and the inverse flux product from the CarbonTracker system. We show that inverse flux estimates using both priors converge to similar posterior estimates (10 TgC difference), in our reference inversion, but some spatial structures from the prior fluxes remain in the posterior fluxes, revealing the importance of the prior flux resolution and distribution despite the large amount of atmospheric data available. The retrieved fluxes were compared to eddy flux towers in the corn and grassland areas, revealing an improvement in the seasonal cycles between the two compared to the prior fluxes, despite large absolute differences due to representation errors. The uncertainty of 35 TgC (about 35 gC m2) was derived from the posterior uncertainty obtained with our reference inversion of about 25 to 30 TgC and from sensitivity tests of the assumptions made in the inverse system, for a mean carbon balance over the region of −178 TgC, slightly weaker than the reference. Because of the potential large bias (~20 TgC in this case) due to choice of background conditions, proportional to the surface but not to the regional flux, this methodology seems limited to regions with a large signal (sink or source), unless additional observations can be used to constrain the boundary inflow.
A method for evaluating bias in global measurements of CO2 total columns from space
Authors: Wunch D. , Wennberg P. O. , Toon G. C. , Connor B. J. , Fisher B. , Osterman G. B. , Frankenberg C. , Mandrake L. , O'Dell C. , Ahonen P. , Biraud S. C. , Castano R. , Cressie N. , Crisp D. , Deutscher N. M. , Eldering A. , Fisher M. L. , Griffith D. W. T. , Gunson M. , Heikkinen P. , Keppel-Aleks G. , Kyrö E. , Lindenmaier R. , Macatangay R. , Mendonca J. , Messerschmidt J. , Miller C. E. , Morino I. , Notholt J. , Oyafuso F. A. , Rettinger M. , Robinson J. , Roehl C. M. , Salawitch R. J. , Sherlock V. , Strong K. , Sussmann R. , Tanaka T. , Thompson D. R. , Uchino O. , Warneke T. , Wofsy S. C.
Published: July 2011

Abstract. We describe a method of evaluating systematic errors in measurements of total column dry-air mole fractions of CO2 (XCO2) from space, and we illustrate the method by applying the method to the Atmospheric CO2 Observations from Space retrievals of the Greenhouse Gases Observing Satellite (ACOS-GOSAT) v2.8 data. The approach exploits the lack of large gradients in XCO2 south of 25° S to identify large-scale offsets and other biases in the ACOS-GOSAT data with several retrieval parameters and errors in instrument calibration. We demonstrate the effectiveness of the method by comparing the ACOS-GOSAT data in the Northern Hemisphere with ground truth provided by the Total Carbon Column Observing Network (TCCON). We use the correlation between free-tropospheric temperature and XCO2 in the Northern Hemisphere to define a dynamically informed coincidence criterion between the ground-based TCCON measurements and the ACOS-GOSAT measurements. We illustrate that this approach provides larger sample sizes, hence giving a more robust comparison than one that simply uses time, latitude and longitude criteria. Our results show that the agreement with the TCCON data improves after accounting for the systematic errors.
A review of the ozone hole from 2008 to 2010 as observed by IASI
Authors: Scannell C. , Hurtmans D. , Boynard A. , Hadji-Lazaro J. , George M. , Delcloo A. , Tuinder O. , Coheur P.-F. , Clerbaux C.
Published: July 2011

Abstract. Atmospheric remote sensing from satellites is essential for the long-term, continuous monitoring of the ozone hole and is critical in order to evaluate stratospheric ozone recovery. During the last decade, thermal infra-red (TIR) sensors have demonstrated their enhanced capability in capturing both the spatial and temporal variability of the ozone hole during the polar night, in contrast to instruments measuring in the ultraviolet-visible (UV-vis) range of the spectrum which need sunlight to operate. In this paper we present a study of the ozone hole as observed by the Infra-red Atmospheric Sounding Interferometer (IASI) on-board the MetOp-A European satellite platform from the beginning of data dissemination, August 2008, to the end of December 2010. Here we demonstrate IASI's ability to capture the seasonal characteristics of the ozone hole. We compare IASI ozone total columns and vertical profiles with those of the Global Ozone Monitoring Experiment 2 (GOME-2) (also on-board MetOp-A) and electrochemical concentration cell (ECC) ozone sonde measurements for the ozone hole region and period. The IASI and GOME-2 ozone total columns were found to be in excellent agreement for this region with a correlation coefficient of 0.97, for September, October and November 2009. IASI on average, exhibits a positive bias of approximately 7 % compared to the GOME-2 measurements over the entire ozone hole period. Comparisons between IASI and ozone sonde measurements were also found to be in good agreement with the percentage difference between both ozone profile measurements being less than ±30 % over the altitude range of 0–40 km. The vertical structure of the ozone hole is in particular captured remarkably good by IASI.
IMF By effects in the plasma flow at the polar cap boundary
Authors: Lukianova R. , Kozlovsky A.
Published: July 2011

Abstract. We used the dataset obtained from the EISCAT Svalbard Radar during 2000–2008 to study statistically the ionospheric convection in a vicinity of the polar cap boundary as related to IMF By conditions separately for northward and southward IMF. The effect of IMF By is manifested in the intensity and direction of the azimuthal component of ionospheric flow. The most significant effect is observed on the day and night sides whereas on dawn and dusk the effect is essentially less prominent. However, there is an asymmetry with respect to the noon-midnight meridian. On the day side the intensity of By-related azimuthal flow is maximal exactly at noon, whereas on the night side the maximum is shifted toward the post-midnight hours (~03:00 MLT). On the dusk side the relative reduction of the azimuthal flow is much larger than that on the dawn side. Overall, the magnetospheric response to IMF By seems to be stronger in the 00:00–12:00 MLT sector compared to the 12:00–24:00 MLTs. Quantitative characteristics of the IMF By effect are presented and partly explained by the magnetospheric electric fields generated due to the solar wind and also by the position of open-closed boundary for different IMF orientation.
Determining the accuracy of gridded climate data and how this varies with observing-network density
Authors: Legg T. P.
Published: July 2011

Abstract. The Met Office National Climate Information Centre regularly produces assessments of mean monthly, seasonal and annual values of weather parameters and their anomalies over the UK. However the gridded values, and corresponding areal-average values, are subject to error. Experiments have been done in an attempt to quantify the mean errors in gridded monthly values and monthly areal averages of temperature and rainfall, and how these errors vary when we artificially thin out the observation network. But there are two additional reasons for this work: firstly we wish to determine how far back we can realistically extend the historical areal series, and secondly, we want to estimate the size of error bars on the historical values. For the UK as a whole, we estimate that error bars of around 0.1 °C would arise for monthly-mean temperatures.
Assimilation of Soil Wetness Index and Leaf Area Index into the ISBA-A-gs land surface model: grassland case study
Authors: Barbu A. L. , Calvet J.-C. , Mahfouf J.-F. , Albergel C. , Lafont S.
Published: July 2011

Abstract. The performance of the joint assimilation in a land surface model of a Soil Wetness Index (SWI) product provided by an exponential filter together with Leaf Area Index (LAI) is investigated. The data assimilation is evaluated with different setups using the SURFEX modeling platform, for a period of seven years (2001–2007), at the SMOSREX grassland site in southwestern France. The results obtained with a Simplified Extended Kalman Filter demonstrate the effectiveness of a joint data assimilation scheme when both SWI and Leaf Area Index are merged into the ISBA-A-gs land surface model. The assimilation of a retrieved Soil Wetness Index product presents several challenges that are investigated in this study. A significant improvement of around 13 % of the root-zone soil water content is obtained by assimilating dimensionless root-zone SWI data. For comparison, the assimilation of in situ surface soil moisture is considered as well. A lower impact on the root zone is noticed. Under specific conditions, the transfer of the information from the surface to the root zone was found not accurate. Also, our results indicate that the assimilation of in situ LAI data may correct a number of deficiencies in the model, such as low LAI values in the senescence phase by using a seasonal-dependent error definition for background and observations. In order to verify the specification of the errors for SWI and LAI products, a posteriori diagnostics are employed. This approach highlights the importance of the assimilation design on the quality of the analysis. The impact of data assimilation scheme on CO2 fluxes is also quantified by using measurements of net CO2 fluxes gathered at the SMOSREX site from 2005 to 2007. An improvement of about 5 % in terms of rms error is obtained.
Mineral dust aerosol from Saharan desert by means of atmospheric, emission, dispersion modelling
Authors: Guarnieri F. , Calastrini F. , Busillo C. , Pasqui M. , Becagli S. , Lucarelli F. , Calzolai G. , Nava S. , Udisti R.
Published: July 2011

Abstract. The application of Numerical Prediction Models to mineral dust cycle is considered of prime importance for the investigation of aerosol and non-CO2 greenhouse gases contributions in climate variability and change. In this framework, a modelling system was developed in order to provide a regional characterization of Saharan dust intrusions over Mediterranean basin. The model chain is based on three different modules: the atmospheric model, the dust emission model and transport/deposition model. Numerical simulations for a selected case study, June 2006, were performed in order to evaluate the modelling system effectiveness. The comparison of the results obtained in such a case study shows a good agreement with those coming from GOCART model. Moreover a good correspondence was found in the comparison with in-situ measurements regarding some specific crustal markers in the PM10 fraction.
Deep ocean ventilation, carbon isotopes, marine sedimentation and the deglacial CO2 rise
Authors: Tschumi T. , Joos F. , Gehlen M. , Heinze C.
Published: July 2011

Abstract. The link between the atmospheric CO2 level and the ventilation state of the deep ocean is an important building block of the key hypotheses put forth to explain glacial-interglacial CO2 fluctuations. In this study, we systematically examine the sensitivity of atmospheric CO2 and its carbon isotope composition to changes in deep ocean ventilation, the ocean carbon pumps, and sediment formation in a global 3-D ocean-sediment carbon cycle model. Our results provide support for the hypothesis that a break up of Southern Ocean stratification and invigorated deep ocean ventilation were the dominant drivers for the early deglacial CO2 rise of ~35 ppm between the Last Glacial Maximum and 14.6 ka BP. Another rise of 10 ppm until the end of the Holocene is attributed to carbonate compensation responding to the early deglacial change in ocean circulation. Our reasoning is based on a multi-proxy analysis which indicates that an acceleration of deep ocean ventilation during early deglaciation is not only consistent with recorded atmospheric CO2 but also with the reconstructed opal sedimentation peak in the Southern Ocean at around 16 ka BP, the record of atmospheric δ13CCO2, and the reconstructed changes in the Pacific CaCO3 saturation horizon.
The effect of slope steepness and antecedent moisture content on interrill erosion, runoff and sediment size distribution in the highlands of Ethiopia
Authors: Defersha M. B. , Quraishi S. , Melesse A.
Published: July 2011

Abstract. Soil erosion is a two-phase process consisting of the detachment of individual particles and their transport by the flowing water. This study discusses the results of laboratory experiments in which for three soils, the runoff depth, sediment yield, splash erosion and sediment size were measured. Rainfall intensity, slope and antecedent moisture contents were varied in the experiment. The soil types ranged from clay to sandy clay loam (Alemaya Black soil, Regosols and Cambisols). Rainfall was applied for six sequential 15-min periods with rainfall intensities varying between 55 and 120 mm h−1. The three slopes tested were 9, 25, and 45 %. Results show that as slope increased from 9 to 25 %, splash erosion and sediment yield increased. An increase in slope from 25 to 45 % generally decreases in splash erosion. Sediment yield for one soil increased and one soil decreased with slope and for the third soil the trend was different between the two initial moisture contents. Sediment yield was correlated (r = 0.66) with runoff amounts but not with splash erosion. Interrill erosion models that were based on the flowing water and rainfall intensity fitted the data better than when based on rainfall intensity solely. Models that assume a positive linear relationship between erosion and slope may overestimate sediment yield.
Analysis of predicted and observed accumulated convective precipitation in the area with frequent split storms
Authors: Ćurić M. , Janc D.
Published: July 2011

Abstract. Convective clouds generate extreme rainfall events and flash floods in small areas with both large spatial and temporal variability. For this reason, the monitoring of the total accumulated precipitation fields at the surface with rain gauges and meteorological radars has both strengths and weakness. Alternatively, a numerical cloud model may be a useful tool to simulate convective precipitation for various analyses and predictions. The main objective of this paper is to show that the cloud-resolving model reproduces well the accumulated convective precipitation obtained from the rain gauge network data in the area with frequent split storms. We perform comparisons between observations and model samples of the areal accumulated convective precipitation for a 15-yr period over treated area. Twenty-seven convective events have been selected. Statistical analyses reveal that the model areal accumulated convective precipitation closely match their observed values with a correlation coefficient of 0.80.
Scaling of peak flows with constant flow velocity in random self-similar networks
Authors: Mantilla R. , Gupta V. K. , Troutman B. M.
Published: July 2011

Abstract. A methodology is presented to understand the role of the statistical self-similar topology of real river networks on scaling, or power law, in peak flows for rainfall-runoff events. We created Monte Carlo generated sets of ensembles of 1000 random self-similar networks (RSNs) with geometrically distributed interior and exterior generators having parameters pi and pe, respectively. The parameter values were chosen to replicate the observed topology of real river networks. We calculated flow hydrographs in each of these networks by numerically solving the link-based mass and momentum conservation equation under the assumption of constant flow velocity. From these simulated RSNs and hydrographs, the scaling exponents β and φ characterizing power laws with respect to drainage area, and corresponding to the width functions and flow hydrographs respectively, were estimated. We found that, in general, φ > β, which supports a similar finding first reported for simulations in the river network of the Walnut Gulch basin, Arizona. Theoretical estimation of β and φ in RSNs is a complex open problem. Therefore, using results for a simpler problem associated with the expected width function and expected hydrograph for an ensemble of RSNs, we give heuristic arguments for theoretical derivations of the scaling exponents β(E) and φ(E) that depend on the Horton ratios for stream lengths and areas. These ratios in turn have a known dependence on the parameters of the geometric distributions of RSN generators. Good agreement was found between the analytically conjectured values of β(E) and φ(E) and the values estimated by the simulated ensembles of RSNs and hydrographs. The independence of the scaling exponents φ(E) and φ with respect to the value of flow velocity and runoff intensity implies an interesting connection between unit hydrograph theory and flow dynamics. Our results provide a reference framework to study scaling exponents under more complex scenarios of flow dynamics and runoff generation processes using ensembles of RSNs.
The multiphase physics of sea ice: a review
Authors: Hunke E. C. , Notz D. , Turner A. K. , Vancoppenolle M.
Published: July 2011

Abstract. Rather than being solid throughout, sea ice contains liquid brine inclusions, solid salts, microalgae, trace elements, gases, and other impurities which all exist in the interstices of a porous, solid ice matrix. This multiphase structure of sea ice arises from the fact that the salt that exists in seawater cannot be embedded into the water-ice crystal lattice upon formation of sea ice, but remains in liquid solution. Depending on the ice porosity (determined by temperature and salinity), this brine can drain from the ice, taking other sea ice constituents with it. Thus, sea ice salinity and microstructure are tightly interconnected and play a significant role in polar ecosystems and climate. As large-scale climate modeling efforts move toward "earth system" simulations that include biological and chemical cycles, renewed interest in the multiphase physics of sea ice has strengthened research initiatives to observe, understand and model this complex system. This review article provides an overview of these efforts, highlighting known difficulties and requisite observations for further progress in the field. We focus on mushy-layer theory, which describes general multiphase materials, and on numerical approaches now being explored to model the multiphase evolution of sea ice and its interaction with chemical, biological and climate systems.
Localized foveal detachment in a patient with central retinal artery occlusion with cilioretinal sparing
Authors: Ozdemir Hakan , Karacorlu Murat , Karacorlu Serra A. , Senturk Fevzi
Published: July 2011

Purpose

To report the optical coherence tomography (OCT) findings of acute central retinal artery occlusion (CRAO) with cilioretinal sparing.

Methods

Optical coherence tomography findings in a 45-year-old man with CRAO with cilioretinal sparing were evaluated.

Results

Optical coherence tomography disclosed diffuse thickening of the neurosensory retina in the perifoveolar area. Increased reflectivity was noted in the inner retinal layers. The hyporeflectivity is observed in the outer retina including the outer neurosensory retina. The photoreceptors are not seen because of the shadowing effect. A localized foveal detachment composed of a dome-shaped retinal elevation over a nonreflective cavity with minimal shadowing of the underlying tissues was seen.

Conclusions

The OCT findings showed that besides the usual OCT findings in acute CRAO, the presence of a cilioretinal artery might lead to the leakage of fluid into the subfoveal space leading to localized detachment.
Apheresis as Rescue Therapy in a Severe Case of Sudden Hearing Loss
Authors: Alpa Mirella , Bucolo Sebastiano , Beatrice Fabio , Giachino Osvaldo , Roccatello Dario
Published: July 2011

A 23-year-old man complained of progressive left ear hearing loss and tinnitus and was unsuccessfully treated with steroids and mannitol. Four months later he presented with sudden, severe, asymmetrical, bilateral sensorineural hearing loss. The results of the laboratory workup were normal except for antinuclear autoantibodies. Auditory brain stem responses showed absent peak and interpeak latencies on both sides. The combination of plasma exchange with high doses of steroids resulted in a definite improvement. Plasmapheresis combined with steroid administration can be used as secondline therapy in idiopathic, sudden sensorineural hearing loss.
Surgical Therapy of End-Stage Heart Failure: Understanding Cell-Mediated Mechanisms Interacting with Myocardial Damage
Authors: Ghodsizad Ali , Loebe Mathias , Piechaczek Christoph , Bordel Viktor , Ungerer Matthias N. , Gregoric Igor , Bruckner Brian , Noon George P. , Karck Matthias , Ruhparwar Arjang
Published: July 2011

Worldwide, cardiovascular disease results in an estimated 14.3 million deaths per year, giving rise to an increased demand for alternative and advanced treatment. Current approaches include medical management, cardiac transplantation, device therapy, and, most recently, stem cell therapy. Research into cell-based therapies has shown this option to be a promising alternative to the conventional methods. In contrast to early trials, modern approaches now attempt to isolate specific stem cells, as well as increase their numbers by means of amplifying in a culture environment. The method of delivery has also been improved to minimize the risk of micro-infarcts and embolization, which were often observed after the use of coronary catheterization. The latest approach entails direct, surgical, transepicardial injection of the stem cell mixture, as well as the use of tissue-engineered meshes consisting of embedded progenitor cells.
Is CD133 a Biomarker for Cancer Stem Cells of Colorectal Cancer and Brain Tumors? A Meta-Analysis
Authors: Yang Kun , Chen Xin-Zu , Zhang Bo , Yang Chen , Chen Hai-Ning , Chen Zhi-Xin , Zhou Zong-Guang , Chen Jia-Ping , Hu Jian-Kun
Published: July 2011

Background

CD133 has been used to identify normal and cancer stem cells from several different tissues. Nowadays some researchers have reported that CD133 expression was not restricted to cancer stem cells (CSCs) of colorectal cancer and brain tumors, and CD133-negative subsets could also initiate tumors. We therefore performed a meta-analysis to assess the value of CD133 as a biomarker of CSCs for colorectal cancer and brain tumors.

Methods

A Medline search was performed to identify relevant studies for the analysis. The meta-analysis was done using RevMan 5.0 software. Outcome measures were colony formation rate and xenotransplanted tumor formation rate.

Results

Fifteen identified studies were available for analysis. For in vitro tests, there were no significant differences in the colony formation rates between CD133-positive and CD133-negative cells for colorectal cancer and brain tumors. For in vivo tests, the xenotransplanted tumor formation rate showed a significant difference between CD133-positive cells and CD133-negative cells in colorectal cancer only, corresponding to a risk difference of 0.40 (95%CI: 0.07, 0.73). Samples (cell lines versus tissues), applied biomarkers (combined versus single), and injection site were included as factors in sensitivity analyses, but the results were very inconsistent.

Conclusions

CD133 may not be suitable as a universe biomarker in identifying CSCs of colorectal cancer and brain tumors. Additional studies are necessary to further delineate its role.
In Situ Characterization of Internal Damage in TRIP‐Steel/Mg‐PSZ Composites under Compressive Stress Using X‐Ray Computed Tomography
Authors: Berek Harry , Ballaschk Uta , Aneziris Christos G.
Published: July 2011

An experimental setup for in situ investigations under compressive stress using laboratory X‐ray computed tomography (XCT) was developed and successfully tested. Complete deformation curves can be taken. It could be shown that XCT scans are possible during brakes of the stopped in situ experiments. In this way the deformation behavior of defined sample regions can be investigated. This kind of experiments is well suited to investigate the deformation behavior of foams and other samples which are transferable for the X‐rays used. The compression of metal matrix composite foams lead to the cooperative collapse of connected cells. We observed deformation bands arising in regions of smaller cell wall thicknesses. The deformation was dependent on size, shape, and orientation of the cells under consideration. Obviously deformation bands start at bigger cells with a small cell wall thickness and some extension perpendicular to the deformation direction. The rising of this kind of deformation bands can be explained by the dramatic change of the stress distribution in the neighbor cells after the first brake of a cell wall.
The scintigraphic index spleen/liver at 30 minutes predicts the success of splenectomy in persistent and chronic primary immune thrombocytopenia
Authors: Roca Manel , Muñiz‐Diaz Eduardo , Mora Jaume , Romero‐Zayas Inmaculada , Ramón Olga , Roig Inmaculada , Pujol‐Moix Núria
Published: July 2011

Splenectomy is considered the second‐line of treatment in patients with chronic primary immune thrombocytopenia (ITP) in whom glucocorticoids have failed. Some patients do not respond to splenectomy or they have postoperative complications. Based on our previous experience using kinetic and scintigraphic parameters, we did a retrospective study with the aim of comparing all these parameters as a means of predicting the success of splenectomy in persistent and chronic primary ITP. Forty‐one consecutive patients with chronic primary ITP refractory to prednisone, who had been splenectomized, were included in the study. The response to splenectomy was assessed by evaluating bleeding and platelet counts before and at different times after surgery. A complete platelet kinetic study was performed before the splenectomy using autologous 111In‐labeled platelets. The scintigraphic parameters measured included different indices between spleen/heart, liver/hearth, and spleen/liver. Thirty‐six patients gave a complete response after splenectomy and five patients did not respond. A statistically significant difference between both groups was found with initial platelet recovery and with some scintigraphic indices which also showed a variable prediction value for the success of splenectomy. Among these indices, the spleen/liver at 30 minutes demonstrated a predictive value with a 100% of sensitivity and a 100% of specificity. Conclusion: some platelet kinetic parameters and scintigraphic indices, in particular the spleen/liver at 30 minutes, were useful to predict the outcome of splenectomy in persistent and chronic primary ITP and, therefore, they should be taken into account when deciding whether or not to perform a splenectomy. Am. J. Hematol. 2011. © 2011 Wiley‐Liss, Inc.
Non‐Hodgkin lymphoma of the prostate
Authors: Steuter John , Weisenburger Dennis D. , Bociek R. Greg , Bierman Philip , Vose Julie , Bast Martin , Loberiza Fausto , Armitage James O.
Published: July 2011

No abtract.
Dominance and innovation: a returns‐based beliefs approach
Authors: Chander Velu  , Sriya Iyer  , Gair Jonathan R.
Published: July 2011

Do dominant or less dominant firms innovate more? There is considerable research on this question, with theoretical studies based on game theory and empirical evidence often divided. We provide a new theory that the decisions that concern strategic choice in innovation may be influenced by expected relative returns. Our approach, which we call the returns‐based beliefs approach, is based upon subjective probabilities. It combines a decision analytic solution concept and Luce's (Individual Choice Behavior, Wiley: New York, 1959) probabilistic choice model. We show that the returns‐based beliefs approach provides support for the thesis that dominant firms invest more in research and development (R&D) within an asymmetric mixed‐strategy game. Consequently, the returns‐based beliefs approach accords better with recent empirical studies of innovation. Using R&D data across a range of industries in the UK from 2001 to 2006, we show that firms’ spending on R&D is related more to their own profitability than to that of their competitors, which is consistent with the returns‐based beliefs approach. Copyright © 2011 John Wiley & Sons, Ltd.
A chiral liquid chromatography method for the simultaneous determination of oxcarbazepine, eslicarbazepine, R‐licarbazepine and other new chemical derivatives BIA 2–024, BIA 2–059 and BIA 2–265, in mouse plasma and brain
Authors: Fortuna Ana , Alves Gilberto , Almeida Anabela , Lopes Bruno , Falcão Amílcar , Soares‐da‐Silva Patrício
Published: July 2011

Recently, in silico models have been developed to predict drug pharmacokinetics. However, before application, they must be validated and, for that, information about structurally similar reference compounds is required. A chiral liquid chromatography method with ultraviolet detection (LC‐UV) was developed and validated for the simultaneous quantification of BIA 2–024, BIA 2–059, BIA 2–265, oxcarbazepine, eslicarbazepine (S‐licarbazepine) and R‐licarbazepine in mouse plasma and brain. Compounds were extracted by a selective solid‐phase extraction procedure and their chromatographic separation was achieved on a LiChroCART 250–4 ChiraDex column using a mobile phase of water–methanol (92:8, v/v) pumped at 0.7 mL/min. The UV detector was set at 235 nm. Calibration curves were linear (r2 ≥ 0.996) over the concentration ranges of 0.2–30 µg/mL for oxcarbazepine, eslicarbazepine and R‐licarbazepine; 0.2–60 µg/mL for the remaining compounds in plasma; and 0.06–15 µg/mL for all the analytes in brain homogenate. Taking into account all analytes at these concentration ranges in both matrices, the overall precision did not exceed 9.09%, and the accuracy was within ±14.3%. This LC‐UV method is suitable for carrying out pharmacokinetic studies with these compounds in mouse in order to obtain a better picture of their metabolic pathways and biodistribution. Copyright © 2011 John Wiley & Sons, Ltd.
The effects of periodized concurrent and aerobic training on oxidative stress parameters, endothelial function and immune response in sedentary male individuals of middle age
Authors: Schaun Maximiliano Isoppo , Dipp Thiago , da Silva Rossato Juliane , Wilhelm Eurico Nestor , Pinto Ronei , Rech Anderson , Plentz Rodrigo Della Méa , Homem de Bittencourt Paulo I. , Reischak‐Oliveira Alvaro
Published: July 2011

The vascular endothelium plays a key role in arterial wall homeostasis by preventing atherosclerotic plaque formation. A primary causal factor of endothelial dysfunction is the reactive oxygen species. Aerobic exercise is ascribed as an important adjuvant therapy in endothelium‐dependent cardiovascular disease. However, little is known about the effects of concurrent (aerobic + strength) training on that. For a comparison of the effects of aerobic and concurrent physical training on endothelial function, oxidative stress parameters and the immunoinflammatory activity of monocytes/macrophages, 20 adult male volunteers of middle age were divided into a concurrent training (CT) programme group and an aerobic training group. The glutathione disulphide to glutathione ratio (GSSG/GSH) and plasma lipoperoxide (LPO) levels, as well as flow‐mediated dilation (FMD), monocyte/macrophage functional activity (zymosan phagocytosis), body lipid profiles, aerobic capacity (maximal oxygen uptake) and strength parameters (one‐repetition maximum test), were measured before and after the exercise training programmes. The CT exhibited reduced acute effects of exercise on the GSSG/GSH ratio, plasma LPO levels and zymosan phagocytosis. The CT also displayed improved lipid profiles, glycaemic control, maximal oxygen uptake and one‐repetition maximum test values. In both the aerobic training and the CT, training improved the acute responses to exercise, as inferred from a decrease in the GSSG/GSH ratios. The aerobic sessions did not alter basal levels of plasma LPO or macrophage phagocytic activity but improved FMD values as well as lipid profiles and glycaemic control. In summary, both training programmes improve systemic redox status and antioxidant defences. However, the aerobic training was more efficient in improving FMD in the individuals studied. Copyright © 2011 John Wiley & Sons, Ltd.
Stent sizing by coronary computed tomographic angiography: Comparison with conventional coronary angiography in an experienced setting
Authors: de Silva Ramesh , Mussap Christian J. , Hecht: Harvey S. , van Mieghem Nicolas M. , Matarazzo Thomas J. , Roubin Gary S. , Panagopoulos Georgia
Published: July 2011

Objectives:

The goal was to compare stent sizing by coronary computed tomographic angiography (CCTA) with that deployed in an experienced setting based upon conventional coronary angiography (CA).

Background:

Stent sizing is currently performed by visual estimation, with infrequent guidance by intravascular ultrasound. CCTA permits quantitative determination of stent length (Stent L) and diameter (Stent D).

Methods:

Projected L (CTA‐Stent L) and D (CTA‐Stent D) were determined from CCTA obtained in 248 patients with 352 lesions undergoing percutaneous coronary intervention within 4 months of the CCTA, and were compared to the Stent‐L and Stent‐D of the actually deployed stents. The effects of lesion modification and calcified plaque were also evaluated.

Results:

There were significant correlations between CTA‐Stent L and Stent L (r = 0.656, P < 0.0001) and between CTA‐Stent D and Stent D (r = 0.40, P < 0.001). Median predicted CTA‐Stent L was slightly longer (20 mm vs. 18 mm, P < 0.0001) and predicted CTA‐Stent D was slightly smaller (3.0 mm vs. 3.2 mm, P < 0.0001) than Stent‐L and Stent‐D, respectively. The differences were unchanged in stents with lesion modification by pre‐dilation or intracoronary nitroglycerin. CTA Stent‐L and CTA Stent‐D increased significantly with increasing calcium (P < 0.0001 and P = 0.019, respectively).

Conclusions:

(1) There are significant correlations between CCTA and CA based stent sizing in an experienced setting. (2) CCTA projects slightly longer and slightly smaller diameter stents than those deployed during PCI irrespective of lesion modification; the small differences are unlikely to have clinical significance. (3) CCTA may offer a noninvasive alternative to intravascular ultrasound for stent planning. © 2011 Wiley‐Liss, Inc.
Successful removal of an entrapped rotablation burr by extracting drive shaft sheath followed by balloon dilatation
Authors: Sakakura Kenichi , Ako Junya , Momomura Shin‐ichi
Published: July 2011

Burr entrapment is a rare but serious complication during rotational atherectomy (RA). Although emergent surgical removal is a reliable option for this complication, surgical removal is invasive and takes several hours. Balloon inflation just proximal to the burr was the previously‐reported nonsurgical option for burr removal. However, this method needed large guide catheter lumen (≥8 Fr). We present a case of 67‐year‐old male on chronic hemodialysis. During RA for severe stenosis of the right coronary artery, the RA burr was entrapped. We cut off the drive shaft, the drive shaft sheath, and the RA wire together near the advancer, and then we removed the drive shaft sheath. After removing the drive shaft sheath, the 2.5 mm balloon easily entered the 7‐Fr guide catheter. We inflated that balloon to a pressure of 18 atm. The burr was easily removed immediately after balloon deflation. Removal of the drive shaft sheath following balloon dilatation is a new, nonsurgical bailout method for a burr that becomes entrapped during RA. Since removal of the drive shaft sheath following balloon dilatation can be applied to 7 Fr as well as 6 Fr guide systems, this method may be of considerable benefit when operators use 7 Fr or 6 Fr systems. © 2011 Wiley‐Liss, Inc.