bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Predisposition to Hallucinations on Non-Clinical Paranoid vs. Socially Anxious Individuals after Hearing Negative Affective-Laden Sounds: An Experimental Investigation
Authors: Lopes Bárbara , Pinto-Gouveia José
Published: September 2012

Background:Research suggested that negative affective-laden sounds act as environmental stressors that elicit negative affect (Bradley and Lang, 2000a).Aims:We tried to test for the role of an interaction between predisposition to hallucinatory experiences and exposure to negative affective laden sounds for the presence of paranoid ideation.Method:We used an experimental design that followed the vulnerability × stress model. We defined three groups from a sample of students: paranoia group vs. social anxiety group vs. control group. Their psychological characteristics were measured through self-reports of paranoia, anxiety, predisposition to hallucinations and depressive symptoms at Time 1 (before the experiment). Participants had to listen to either negative affective laden sounds (e.g. screaming) or positive affective laden sounds (e.g. sound of ocean waves). Their paranoid ideation and positive vs. negative emotional reactions to sounds were measured through self-reports at Time 2 (after the experiment).Results:Data showed that the paranoia group presented more serious psychological vulnerabilities than the social anxiety group. A MANCOVA also showed that the independent variables (“group” and “experimental sound conditions”) had statistically significant main effects on general paranoia ideation at Time 2. Furthermore, there was a significant three-way interaction between group x predisposition to hallucinatory experiences × experimental condition of sounds for the presence of general paranoid ideation at Time 2. Limitations included the small sample size and the effects of parasite variables, e.g. noise.Conclusions:Individuals’ predisposition for hallucinatory experiences increases the probability of possessing paranoid ideation. This tendency is a characteristic of paranoid non-clinical individuals.
Sowing the seeds of social relations: social capital and agricultural diversity in Hararghe Ethiopia
Authors: Cavatassi Romina , Lipper Leslie , Winters Paul
Published: September 2012

The paper presents an analysis of the role of two forms of social capital – linking and bonding – on two key farm outcomes: on-farm crop diversity and household wellbeing. Where market transactions are limited, social capital is an important household asset for accessing seed and channelling information. The study is set in a drought-prone region of Ethiopia, with high rates of food insecurity and dependency on agriculture for livelihoods. The region is very rich in crop genetic diversity, particularly for sorghum. The data were collected for a production year that experienced a major drought shock. Results of the analysis indicate that social capital is an important determinant of farm level diversity and wellbeing, with opposing effects related to the two different forms of social capital. This suggests possible trade-offs between the two forms of social capital in terms of food security, production and diversity, which need to be considered in planning interventions.
Socio-economic inequalities in malnutrition among children and adolescents in Colombia: the role of individual-, household- and community-level characteristics
Authors: Garcia Sandra , Sarmiento Olga L , Forde Ian , Velasco Tatiana
Published: September 2012

Objective

To examine socio-economic inequalities in malnutrition among Colombian children and adolescents, and to assess the contribution of individual-, household- and community-level factors to those inequalities.

Design

Cross-sectional data were used from two sources: 2005 Colombian Demographic and Health Survey and 2005 Colombian census. Malnutrition outcomes included stunting and overweight. Multilevel Poisson models were used to estimate the association between individual, household and contextual characteristics and malnutrition. Changes in prevalence ratios of the poorest quintile (v. richest) were compared to assess the contribution of different characteristics to inequalities in malnutrition.

Setting

Population-based, representative of Colombia.

Subjects

Children and adolescents <18 years of age (n 30 779) from the Colombian Demographic and Health Survey.

Results

Children and adolescents living in the poorest households were close to five times more likely to be stunted, while those from the richest households were 1·3–2·8 times more likely than their poorest counterparts to be overweight. Care practices and household characteristics, particularly mother's education, explained over one-third of socio-economic inequalities in stunting. The proportion explained by access to services was not negligible (between 6 % and 14 %). Access to sanitation was significantly associated with a lower prevalence of stunting for all age groups. Between 14 % and 32 % of socio-economic disparities in overweight were explained by maternal and household characteristics. Mother's overweight was positively associated with overweight of the child.

Conclusion

Socio-economic inequalities in stunting and overweight coexist among children and adolescents in Colombia. Malnutrition inequalities are largely explained by household characteristics, suggesting the need for targeted interventions.
Inferring catchment precipitation by doing hydrology backward: A test in 24 small and mesoscale catchments in Luxembourg
Authors: Krier R. , Matgen P. , Goergen K. , Pfister L. , Hoffmann L. , Kirchner J. W. , Uhlenbrook S. , Savenije H. H. G.
Published: September 2012

The complexity of hydrological systems and the necessary simplification of models describing these systems remain major challenges in hydrological modeling. Kirchner's (2009) approach of inferring rainfall and evaporation from discharge fluctuations by “doing hydrology backward” is based on the assumption that catchment behavior can be conceptualized with a single storage‐discharge relationship. Here we test Kirchner's approach using a densely instrumented hydrologic measurement network spanning 24 geologically diverse subbasins of the Alzette catchment in Luxembourg. We show that effective rainfall rates inferred from discharge fluctuations generally correlate well with catchment‐averaged precipitation radar estimates in catchments ranging from less than 10 to more than 1000 km2in size. The correlation between predicted and observed effective precipitation was 0.8 or better in 23 of our 24 catchments, and prediction skill did not vary systematically with catchment size or with the complexity of the underlying geology. Model performance improves systematically at higher soil moisture levels, indicating that our study catchments behave more like simple dynamical systems with unambiguous storage‐discharge relationships during wet conditions. The overall mean correlation coefficient for all subbasins for the entire data set increases from 0.80 to 0.95, and the mean bias for all basins decreases from –0.61 to –0.35 mm d−1. We propose an extension of Kirchner's approach that uses in situ soil moisture measurements to distinguish wet and dry catchment conditions.
Optimal reliable design and operation of water distribution systems through decomposition
Authors: Ostfeld Avi
Published: September 2012

Reliability in general, and in water distribution systems in particular, is a measure of probabilistic performance. A system is said to be reliable if it functions properly for a given time interval and within boundary conditions. Although water distribution system reliability has attracted considerable research attention over the last three decades, there is still no consensus on what reliability measures or evaluation methodologies should be used for the design/operation of water distribution systems. No system is perfectly reliable. In every system undesirable events—failures—can cause a decline or interruption in system performance. Failures are of a stochastic nature and are the result of unpredictable events that occur in the system itself and/or in its environs. A least cost design problem with normal design loadings will result in the cheapest system, but this system will have minimum residual capacity. However, if an increased loading (i.e., higher than the normal design) is implemented, the system's capacity will be increased, thus improving its residual capacity. Finding this “virtual increased loading,” which results in a minimum cost residual system capacity that sustains a required reliability level, is the essence of the proposed methodology, which follows decomposition. The methodology is demonstrated on two example applications of increasing complexity. The main limitation of the suggested method for further extensions to real sized water distribution systems is the computational effort associated with the computation of the “inner” problem. Exploring the required computational burden divided between the “outer” and “inner” problems is a major challenge for future elaborations of this approach.
Seismicity of the Atlantis Massif detachment fault, 30°N at the Mid‐Atlantic Ridge
Authors: Collins John A. , Smith Deborah K. , McGuire Jeffrey J.
Published: September 2012

At the oceanic core complex that forms the Atlantis Massif at 30°N on the Mid‐Atlantic Ridge, slip along the detachment fault for the last 1.5–2 Ma has brought lower crust and mantle rocks to the seafloor. Hydroacoustic data collected between 1999 and 2003 suggest that seismicity occurred near the top of the Massif, mostly on the southeastern section, while detected seismicity along the adjacent ridge axis was sparse. In 2005, five short‐period ocean bottom seismographs (OBS) were deployed on and around the Massif as a pilot experiment to help constrain the distribution of seismicity in this region. Analysis of six months of OBS data indicates that, in contrast to the results of the earlier hydroacoustic study, the vast majority of the seismicity is located within the axial valley. During the OBS deployment, and within the array, seismicity was primarily composed of a relatively constant background rate and two large aftershock sequences that included 5 teleseismic events with magnitudes between 4.0 and 4.5. The aftershock sequences were located on the western side of the axial valley adjacent to the Atlantis Massif and close to the ridge‐transform intersection. They follow Omori's law, and constitute more than half of the detected earthquakes. The OBS data also indicate a low but persistent level of seismicity associated with active faulting within the Atlantis Massif in the same region as the hydroacoustically detected seismicity. Within the Massif, the data indicate a north‐south striking normal fault, and a left‐lateral, strike‐slip fault near a prominent, transform‐parallel, north‐facing scarp. Both features could be explained by changes in the stress field at the inside corner associated with weak coupling on the Atlantis transform. Alternatively, the normal faulting within the Massif might indicate deformation of the detachment surface as it rolls over to near horizontal from an initial dip of about 60° beneath the axis, and the strike‐slip events may indicate transform‐parallel movement on adjacent detachment surfaces.
Inconsistent magnetic polarities in magnetite‐ and greigite‐bearing sediments: Understanding complex magnetizations in the late Messinian in the Adana Basin (southern Turkey)
Authors: Lucifora Stella , Cifelli Francesca , Mattei Massimo , Sagnotti Leonardo , Cosentino Domenico , Roberts Andrew P.
Published: September 2012

We present paleomagnetic, rock magnetic and scanning electron microscope data from three upper Messinian stratigraphic sections from the Adana Basin (southern Turkey). The collected samples are from fine‐grained units, which were deposited during the Messinian Salinity Crisis (within subchron C3r). Paleomagnetic results reveal an inconsistent polarity record, related to a mixture of magnetite and greigite that hinders determination of a reliable magnetostratigraphy. Three classes of samples are recognized on the basis of paleomagnetic results. The first is characterized by a single magnetization component, with normal polarity, that is stable up to 530–580°C and is carried by magnetite. The second is characterized by a single magnetization component, with reversed polarity, that is stable up to 330–420°C. This magnetization is due to greigite, which developed after formation of slumps and before tectonic tilting of the studied successions. The third is characterized by reversed polarity, which is stable up to 530–580°C. We interpret this component as a primary magnetization carried by fine‐grained and magnetically stable detrital magnetite. Results indicate that in the Adana Basin the assumption that a primary magnetization is carried by magnetite, and a magnetic overprint carried by greigite, does not hold because a late magnetic overprint has also been found for magnetite‐bearing samples. Our data illustrate the complexity of magnetostratigraphic reconstructions in successions characterized by variable mixtures of magnetic minerals with different magnetic stability that formed at different stages. We demonstrate the need to perform detailed magnetic mineralogy analyses when conducting magnetostratigraphic studies of clay‐rich sediments from marine or lacustrine environments.
Tracing the Paleo sulfate‐methane transition zones and H2S seepage events in marine sediments: An application of C‐S‐Mo systematics
Authors: Peketi A. , Mazumdar (corresponding author) A. , Joshi R. K. , Patil D. J. , Srinivas P. L. , Dayal A. M.
Published: September 2012

Microbially mediated anaebic oxidation of methane (AOM) coupled with sulfate consumption within the sulfate methane transition zone (SMTZ) in marine sediments is a widely recorded biogeochemical reaction and has profound influence on the atmospheric CH4budget, marine carbon cycle and composition of sediment pore fluids. Recognizing the paleo‐SMTZs in the marine sediments/rock records can throw light on the variation of paleo‐methane fluxes and occurrences of cold seep (H2S + CH4) events through geologic time. Here, we present results from carbonate carbon, pyrite sulfur and molybdenum analyses for two sediment cores overlying the methane hydrate deposits in the Bay of Bengal. The results show intimate association of isotopically depleted carbonate carbon and enriched pyrite sulfur, constraining the paleo SMTZ within the sediment column. In addition, anomalous enrichments of Mo concentrations indicate hydrogen sulfide seepage events. Here, we propose a geochemical tool using C‐S‐Mo sytematics to decipher the paleo‐SMTZs in marine sediments and rocks.
Liquid‐liquid phase separation in aerosol particles: Dependence on O:C, organic functionalities, and compositional complexity
Authors: Song M. , Marcolli C. , Krieger U. K. , Zuend A. , Peter T.
Published: September 2012

Atmospheric aerosol particles may undergo liquid‐liquid phase separation (LLPS) when exposed to varying relative humidity. In this study we investigated the occurrence of LLPS for mixtures consisting of up to ten organic compounds, ammonium sulfate, and water in relationship with the organic oxygen‐to‐carbon (O:C) ratio. LLPS always occurred for O:C < 0.56, never occurred for O:C > 0.80, and depended on the specific types and compositions of organic functional groups in the regime 0.56 < O:C < 0.80. In the intermediate regime, mixtures with a high share of aromatic compounds shifted the limit of occurrence of LLPS to lower O:C ratios. The number of mixture components and the spread of the O:C range did not notably influence the conditions for LLPS to occur. Since in ambient aerosols O:C range typically between 0.2 and 1.0, LLPS is expected to be a common feature of tropospheric aerosols.
Multi‐decadal glacier surface lowering in the Antarctic Peninsula
Authors: Kunz Matthias , King Matt A. , Mills Jon P. , Miller Pauline E. , Fox Adrian J. , Vaughan David G. , Marsh Stuart H.
Published: September 2012

From approximately 400 glaciers of the western Antarctic Peninsula, no in situ records of mass balance exist and their recent contribution to sea level is consequently poorly constrained. We seek to address this shortcoming by using surface elevations from USGS and BAS airborne (1948–2005) and ASTER spaceborne (2001–2010) stereo imagery, combined by using a rigorous semi‐automated registration approach, to determine multi‐decadal glacier surface elevation changes in the western Antarctic Peninsula for 12 glaciers. All observed glaciers show near‐frontal surface lowering and an annual mean lowering rate of 0.28 ± 0.03 m/yr at the lower portion of the glaciers during the ∼4 decades following the mid‐1960s, with higher rates for the glaciers in the north‐west parts of the Antarctic Peninsula. Increased lowering of up to 0.6 m/yr can be observed since the 1990s, in close correspondence to increased atmospheric positive degree days. In all cases, surface lowering reduces to zero within 5 km of the glacier front at around 400 m altitude. This lowering may have been at least partially compensated for by increased high‐altitude accumulation.
Dissecting soil moisture‐precipitation coupling
Authors: Wei Jiangfeng , Dirmeyer Paul A.
Published: September 2012

The ability of soil moisture to affect precipitation (SM‐P) can be dissected into the ability of soil moisture to affect evapotranspiration (ET; SM‐ET) and the ability of ET to affect precipitation (ET‐P). SM‐ET is a local process that is relatively easy to quantify, but ET‐P includes nonlocal atmospheric processes and is more complex. Here, ET‐P is quantified both locally and remotely with a back‐trajectory method for water vapor transport, using corrected reanalysis data. It is found that, for SM‐P and ET‐P, local impact is greater than that from remote for most land areas with significant local impacts. By examining the responses of the three metrics (SM‐ET, ET‐P, and SM‐P) to climate variations over different climate regimes, we show that SM‐ET is the principal factor that determines the spatial pattern and variation of SM‐P. For climatologically wet regions, SM‐ET and SM‐P are higher during dry periods, and vice versa for climatologically dry regions. All three metrics show highest values over the transitional zones.
The vertical and spatial structure of ENSO in the upper troposphere and lower stratosphere from GPS radio occultation measurements
Authors: Scherllin‐Pirscher B. , Deser C. , Ho S.‐P. , Chou C. , Randel W. , Kuo Y.‐H.
Published: September 2012

The vertical and spatial structure of the atmospheric El Niño‐Southern Oscillation (ENSO) signal is investigated using radio occultation (RO) data from August 2006 to December 2010. Due to their high vertical resolution and global coverage, RO data are well suited to describe the full 3‐dimensional ENSO structure in the troposphere and lower stratosphere. We find that interannual temperature anomalies in the equatorial region show a natural decomposition into zonal‐mean and eddy (deviations from the zonal‐mean) components that are both related to ENSO. Consistent with previous studies, we find that during the warm phase of ENSO, zonal‐mean temperatures increase in the tropical troposphere and decrease in the tropical stratosphere. Maximum warming occurs above 8 km, and the transition between warming and cooling occurs near the tropopause. This zonal‐mean response lags sea surface temperature anomalies in the eastern equatorial Pacific by 3 months. The atmospheric eddy component, in contrast, responds rapidly (within 1 month) to ENSO forcing. This signal features a low‐latitude dipole between the Indian and Pacific Oceans, with off‐equatorial maxima centered around 20° to 30° latitude in both hemispheres. The eddy response pattern attains maximum amplitude in the upper troposphere near 11 km and (with opposite polarity) in a shallow layer near the tropopause at approximately 17 km. The eddy ENSO signal tends to be out‐of‐phase between low and middle latitudes in both the troposphere and lower stratosphere.
Southern Hemisphere jet latitude biases in CMIP5 models linked to shortwave cloud forcing
Authors: Ceppi Paulo , Hwang Yen‐Ting , Frierson Dargan M. W. , Hartmann Dennis L.
Published: September 2012

Substantial biases in shortwave cloud forcing (SWCF) of up to ±30 W m−2are found in the midlatitudes of the Southern Hemisphere in the historical simulations of 34 CMIP5 coupled general circulation models. The SWCF biases are shown to induce surface temperature anomalies localized in the midlatitudes, and are significantly correlated with the mean latitude of the eddy‐driven jet, with a negative SWCF bias corresponding to an equatorward jet latitude bias. Aquaplanet model experiments are performed to demonstrate that the jet latitude biases are primarily induced by the midlatitude SWCF anomalies, such that the jet moves toward (away from) regions of enhanced (reduced) temperature gradients. The results underline the necessity of accurately representing cloud radiative forcings in state‐of‐the‐art coupled models.
Baroclinic adjustment in Drake Passage driven by tropical Pacific forcing
Authors: Close Sally E. , Naveira Garabato Alberto C.
Published: September 2012

The time series of high‐quality hydrographic measurements of the ACC in Drake Passage is revisited to investigate the extent of baroclinic adjustment in the region on time scales of up to two decades. We find that substantial adjustment of the upper kilometer of northern Drake Passage has occurred on interannual to decadal time scales, driven primarily by tropical Pacific forcing via the poleward propagation of boundary waves. The decadal‐scale signal consists of a marked deepening of isopycnals (by ∼200 m between the early 1990s and the late 2000s), and reflects ENSO‐forced wind‐driven baroclinic changes over an extensive region of the eastern South Pacific.
Tropical daytime lower D‐region dependence on sunspot number
Authors: Thomson Neil R. , Rodger Craig J. , Clilverd Mark A.
Published: September 2012

Observed phases and amplitudes of VLF radio signals propagating on (near) tropical all‐sea paths, both short, ∼300 km, and long, ∼10 Mm, are used to find daytime parameter changes for the lowest edge of the (D‐region of the) Earth's ionosphere as the solar cycle advanced from a very low sunspot number of ∼5 up to ∼60, in the period 2009–2011. The VLF phases, relative to GPS 1‐s pulses, and amplitudes were measured ∼100 km from the transmitter, where the direct ground wave is very dominant, ∼300 km from the transmitter, near where the ionospherically reflected waves form a (modal) minimum with the ground wave, and ∼10 Mm away where the lowest order waveguide mode is fully dominant. Most of the signals came from the 19.8 kHz, 1‐MW transmitter, NWC, North West Cape, Australia, propagating ENE, mainly over the sea, to the vicinity of Karratha and Dampier on the NW coast of Australia and then on to Kauai, Hawaii, ∼10.6 Mm from NWC. Observations from the 8.1‐Mm path NPM (21.4 kHz, Hawaii) to Dunedin, NZ, are also used. The sunspot number increase from ∼5 to ∼60 was found to coincide with a decrease in the height,H′, of the midday tropical ionosphere by 0.75 ± 0.25 km (from H′ ≈ 70.5 km to H′ ≈ 69.7 km) while the sharpness, β increased by 0.025 ± 0.01 km−1 (from β ≈ 0.47 km−1 to β ≈ 0.49 km−1) where H′ and βare the traditional height and sharpness parameters used by Wait and by the U.S. Navy in their Earth‐ionosphere VLF radio waveguide programs.
Emergence of the active magnetotail plasma sheet boundary from transient, localized ion acceleration
Authors: Zhou X.‐Z. , Angelopoulos V. , Runov A. , Liu J. , Ge Y. S.
Published: September 2012

Observations of the Earth's magnetotail plasma sheet boundary layer (PSBL) have been typically accompanied by field‐aligned crescent‐shaped ion beams, thought to emanate at distant or mid‐tail semi‐permanent or impulsive acceleration sites. Typically such observations, and the theoretical and modeling efforts to explain them, have been disjoint from the adjacent plasma sheet properties near the equatorial projection of the observation. Thus the plasma sheet boundary layer has been thought of as a harbinger of remote, rather than local plasma sheet activity, exception of plasma sheet expansions during the recovery phase of substorms. Using case and statistical studies from THEMIS, obtained simultaneously at the near‐Earth PSBL and at its adjacent central plasma sheet (CPS), we study the transient and impulsive nature of PSBL beams and their inherent connection with CPS bursty bulk flows and associated dipolarization fronts. We show that PSBL beams typically commence a few minutes before CPS flow bursts, which in turn are seen tens of seconds ahead of the arrival of dipolarization fronts. These timing correlations, the crescent shapes of PSBL ion beams, the CPS ion flux enhancements in the earthward and dawnward directions, and other particle distribution characteristics can all be well reproduced by a simple model of ion reflection and acceleration at earthward‐propagating dipolarization fronts associated with CPS flow bursts. The emerging paradigm, therefore, unifies impulsive transport phenomena across latitudes in the near‐Earth magnetotail plasma sheet.
Ozone dynamics and snow‐atmosphere exchanges during ozone depletion events at Barrow, Alaska
Authors: Helmig Detlev , Boylan Patrick , Johnson Bryan , Oltmans Sam , Fairall Chris , Staebler Ralf , Weinheimer Andrew , Orlando John , Knapp David J. , Montzka Denise D. , Flocke Frank , Frieß Udo , Sihler Holger , Shepson Paul B.
Published: September 2012

The behavior of lower atmospheric ozone and ozone exchanges at the snow surface were studied using a suite of platforms during the Ocean‐Atmosphere‐Sea Ice‐Snow (OASIS) Spring 2009 experiment at an inland, coastal site east of Barrow, Alaska. A major objective was to investigate if and how much chemistry at the snow surface at the site contributes to springtime ozone depletion events (ODEs). Between March 8 and April 16, seven ODEs, with atmospheric ozone dropping below 1.0 ppbv, were observed. The depth of the ozone‐depleted layer was variable, extending from the surface to ∼200–800 m. ODEs most commonly occurred during low wind speed conditions with flow coming from the Arctic Ocean. Two high‐sensitivity ozone chemiluminescence instruments were used to accurately define the remaining sub‐ppbv ozone levels during ODEs. These measurements showed variable residual ODE ozone levels ranging between 0.010 and 0.100 ppbv. During the most extended ODE, when ozone remained below 1.0 ppbv for over 78 h, these measurements showed a modest ozone recovery or production in the early afternoon hours, resulting in increases in the ozone mixing ratio of 0.100 to 0.800 ppbv. The comparison between high‐sensitivity ozone measurements and BrO measured by longpath differential absorption spectroscopy (DOAS) during ODEs indicated that at low ozone levels formation of BrO is controlled by the amount of available ozone. Measurements of ozone in air drawn from below the snow surface showed depleted ozone in the snowpack, with levels consistently remaining <6 ppbv independent of above‐surface ambient air concentrations. The snowpack was always a sink of ozone. Ozone deposition velocities determined from ozone surface flux measurements by eddy covariance were on the order of 0.01 cm s−1, which is of similar magnitude as ozone uptake rates found over snow at other polar sites that are not subjected to ODEs. The results from these multiple platform measurements unequivocally show that snow‐atmosphere chemical exchanges of ozone at the measurement site do not exhibit a major contribution to ozone removal from the boundary layer and the formation of ODE.
On the influence of North Pacific sea surface temperature on the Arctic winter climate
Authors: Hurwitz M. M. , Newman P. A. , Garfinkel C. I.
Published: September 2012

Differences between two ensembles of Goddard Earth Observing System Chemistry‐Climate Model simulations isolate the impact of North Pacific sea surface temperatures (SSTs) on the Arctic winter climate. One ensemble of extended winter season forecasts is forced by unusually high SSTs in the North Pacific, while in the second ensemble SSTs in the North Pacific are unusually low. High – Low differences are consistent with a strengthened Western Pacific atmospheric teleconnection pattern, and in particular, a weakening of the Aleutian low. This relative change in tropospheric circulation inhibits planetary wave propagation into the stratosphere, in turn reducing polar stratospheric temperature in mid‐ and late winter. The number of winters with sudden stratospheric warmings is approximately tripled in the Low ensemble as compared with the High ensemble. Enhanced North Pacific SSTs, and thus a more stable and persistent Arctic vortex, lead to a relative decrease in lower stratospheric ozone in spring, affecting the April clear‐sky UV index at Northern Hemisphere midlatitudes.
Can a sinking metallic diapir generate a dynamo?
Authors: Monteux Julien , Schaeffer Nathanaël , Amit Hagay , Cardin Philippe
Published: September 2012

Metallic diapirs may have strongly contributed to core formations during the first million years of planetary evolutions. The aim of this study is to determine whether the dynamics induced by the diapir sinking can drive a dynamo and to characterize the required conditions on the size of the diapir, the mantle viscosity and the planetary latitude at which the diapir sinks. We impose a classical Hadamard flow solution for the motion at the interface between a spherical sinking diapir and a viscous mantle on dynamical simulations that account for rotational and inertial effects in order to model the flow within the diapir. The flows are confined to a velocity layer with a thickness that decreases with increasing rotation rate. These 3D flows are is then used as input for kinematic dynamo simulations to determine the critical magnetic Reynolds number for dynamo onset. Our results demonstrate that the flow pattern inside a diapir sinking into a rotating planet can generate a magnetic field. Large diapirs (R > 10 km) sinking in a mantle with a viscosity ranging from 109 to 1014 Pa.s provide plausible conditions for a dynamo. Equatorial sinking diapirs are confined to a thicker velocity layer and are thus possibly more favorable for dynamo generation than polar sinking diapirs. In addition equatorial sinking diapirs produce stronger saturated magnetic fields. However, for the range of parameters studied here, estimation of the intensity of diapir‐driven magnetic fields suggests that they could not have contributed to the lunar or Martian crustal paleomagnetic fields.
Ion densities and composition of Titan's upper atmosphere derived from the Cassini Ion Neutral Mass Spectrometer: Analysis methods and comparison of measured ion densities to photochemical model simulations
Authors: Mandt Kathleen E. , Gell David A. , Perry Mark , Hunter Waite J. , Crary Frank A. , Young David , Magee Brian A. , Westlake Joseph H. , Cravens Thomas , Kasprzak Wayne , Miller Greg , Wahlund Jan‐Erik , Ågren Karin , Edberg Niklas J. T. , Heays Alan N. , Lewis Brenton R. , Gibson Stephen T. , de la Haye V. , Liang Mao‐Chang
Published: September 2012

The Cassini Ion Neutral Mass Spectrometer (INMS) has measured both neutral and ion species in Titan's upper atmosphere and ionosphere and the Enceladus plumes. Ion densities derived from INMS measurements are essential data for constraining photochemical models of Titan's ionosphere. The objective of this paper is to present an optimized method for converting raw data measured by INMS to ion densities. To do this, we conduct a detailed analysis of ground and in‐flight calibration to constrain the instrument response to ion energy, the critical parameter on which the calibration is based. Data taken by the Cassini Radio Plasma Wave Science Langmuir Probe and the Cassini Plasma Spectrometer Ion Beam Spectrometer are used as independent measurement constraints in this analysis. Total ion densities derived with this method show good agreement with these data sets in the altitude region (∼1100–1400 km) where ion drift velocities are low and the mass of the ions is within the measurement range of the INMS (1–99 Daltons). Although ion densities calculated by the method presented here differ slightly from those presented in previous INMS publications, we find that the implications for the science presented in previous publications is mostly negligible. We demonstrate the role of the INMS ion densities in constraining photochemical models and find that (1) cross sections having high resolution as a function of wavelength are necessary for calculating the initial photoionization products and (2) there are disagreements between the measured ion densities representative of the initial steps in Titan photochemistry that require further investigation.
Microbial communities in the subglacial waters of the Vatnajökull ice cap, Iceland
Authors: Marteinsson Viggó Thór , Rúnarsson Árni , Stefánsson Andri , Thorsteinsson Thorsteinn , Jóhannesson Tómas , Magnússon Sveinn H , Reynisson Eyjólfur , Einarsson Bergur , Wade Nicole , Morrison Hilary G , Gaidos Eric
Published: September 2012

Subglacial lakes beneath the Vatnajökull ice cap in Iceland host endemic communities of microorganisms adapted to cold, dark and nutrient-poor waters, but the mechanisms by which these microbes disseminate under the ice and colonize these lakes are unknown. We present new data on this subglacial microbiome generated from samples of two subglacial lakes, a subglacial flood and a lake that was formerly subglacial but now partly exposed to the atmosphere. These data include parallel 16S rRNA gene amplicon libraries constructed using novel primers that span the v3–v5 and v4–v6 hypervariable regions. Archaea were not detected in either subglacial lake, and the communities are dominated by only five bacterial taxa. Our paired libraries are highly concordant for the most abundant taxa, but estimates of diversity (abundance-based coverage estimator) in the v4–v6 libraries are 3–8 times higher than in corresponding v3–v5 libraries. The dominant taxa are closely related to cultivated anaerobes and microaerobes, and may occupy unique metabolic niches in a chemoautolithotrophic ecosystem. The populations of the major taxa in the subglacial lakes are indistinguishable (>99% sequence identity), despite separation by 6 km and an ice divide; one taxon is ubiquitous in our Vatnajökull samples. We propose that the glacial bed is connected through an aquifer in the underlying permeable basalt, and these subglacial lakes are colonized from a deeper, subterranean microbiome.
Organic Chemistry of Drug Degradation
Authors: Li Min
Published: September 2012

The vast majority of drugs are organic molecular entities. A clear understanding of the organic chemistry of drug degradation is essential to maintaining the stability, efficacy, and safety of a drug product throughout its shelf-life. During analytical method development, stability testing, and pharmaceutical manufacturing troubleshooting activities, one of the frequently occurring and usually challenging events would be the identification of drug degradants and understanding of drug degradation mechanisms and pathways. This book is written by a veteran of the pharmaceutical industry who has first-hand experience in drug design and development, drug degradation mechanism studies, analytical development, and manufacturing process troubleshooting and improvement. The author discusses various degradation pathways with an emphasis on the mechanisms of the underlying organic chemistry, which should aid greatly in the efforts of degradant identification, formulation development, analytical development, and manufacturing process improvement. Organic reactions that are significant in drug degradation will first be reviewed and then illustrated by examples of drug degradation reported in the literature. The author brings the book to a close with a final chapter dedicated to the strategy for rapid elucidation of drug degradants with regard to the current regulatory requirements and guidelines. One chapter that should be given special attention is Chapter 3, Oxidative Degradation. Oxidative degradation is one of the most common degradation pathways but perhaps the most complex one. This chapter employs more than sixty drug degradation case studies with in-depth discussion in regard to their unique degradation pathways. With the increasing regulatory requirements on the quality and safety of pharmaceutical products, in particular with regard to drug impurities and degradants, the book will be an invaluable resource for pharmaceutical and analytical scientists who engage in formulation development, analytical development, stability studies, degradant identification, and support of manufacturing process improvement. In addition, it will also be helpful to scientists engaged in drug discovery and development as well as in drug metabolism studies.
The yeast vacuolar ABC transporter Ybt1p regulates membrane fusion through Ca2+ transport modulation
Authors: Sasser Terry L. , Padolina Mark , Fratti Rutilio A.
Published: September 2012

Ybt1p is a class C ABC transporter (ATP-binding cassette transporter) that is localized to the vacuole of Saccharomyces cerevisiae. Although Ybt1p was originally identified as a bile acid transporter, it has also been found to function in other capacities, including the translocation of phosphatidylcholine to the vacuole lumen, and the regulation of Ca2+ homoeostasis. In the present study we found that deletion of YBT1 enhanced in vitro homotypic vacuole fusion by up to 50% relative to wild-type vacuoles. The increased vacuole fusion was not due to aberrant protein sorting of SNAREs (soluble N-ethylmaleimide-sensitive factor-attachment protein receptors) or recruitment of factors from the cytosol such as Ypt7p and the HOPS (homotypic fusion and vacuole protein sorting) tethering complex. In addition, ybt1Δ vacuoles displayed no observable differences in the formation of SNARE complexes, interactions between SNAREs and HOPS, or formation of vertex microdomains. However, the absence of Ybt1p caused significant changes in Ca2+ transport during fusion. One difference was the prolonged Ca2+ influx exhibited by ybt1Δ vacuoles at the start of the fusion reaction. We also observed a striking delay in SNARE-dependent Ca2+ efflux. As vacuole fusion can be inhibited by high Ca2+ concentrations, we suggest that the delayed efflux in ybt1Δ vacuoles leads to the enhanced SNARE function.
MpaA is a murein-tripeptide-specific zinc carboxypeptidase that functions as part of a catabolic pathway for peptidoglycan-derived peptides in γ-proteobacteria
Authors: Maqbool Abbas , Hervé Mireille , Mengin-Lecreulx Dominique , Wilkinson Anthony J. , Thomas Gavin H.
Published: September 2012

The murein peptide amidase MpaA is a cytoplasmic enzyme that processes peptides derived from the turnover of murein. We have purified the enzyme from Escherichia coli and demonstrated that it efficiently hydrolyses the γ-D-glutamyl-diaminopimelic acid bond in the murein tripeptide (L-Ala-γ-D-Glu-meso-Dap), with Km and kcat values of 0.41±0.05 mM and 38.3±10 s−1. However, it is unable to act on the murein tetrapeptide (L-Ala-γ-D-Glu-meso-Dap-D-Ala). E. coli MpaA is a homodimer containing one bound zinc ion per chain, as judged by mass spectrometric analysis and size-exclusion chromatography. To investigate the structure of MpaA we solved the crystal structure of the orthologous protein from Vibrio harveyi to 2.17 Å (1Å=0.1 nm). Vh_MpaA, which has identical enzymatic and biophysical properties to the E. coli enzyme, has high structural similarity to eukaryotic zinc carboxypeptidases. The structure confirms that MpaA is a dimeric zinc metalloprotein. Comparison of the structure of MpaA with those of other carboxypeptidases reveals additional structure that partially occludes the substrate-binding groove, perhaps explaining the narrower substrate specificity of the enzyme compared with other zinc carboxypeptidases. In γ-proteobacteria mpaA is often located adjacent to mppA which encodes a periplasmic transporter protein previously shown to bind murein tripeptide. We demonstrate that MppA can also bind murein tetrapeptide with high affinity. The genetic coupling of these genes and their related biochemical functions suggest that MpaA amidase and MppA transporter form part of a catabolic pathway for utilization of murein-derived peptides that operates in γ-proteobacteria in addition to the established murein recycling pathways.
Hepatitis B virus: from immunobiology to immunotherapy
Authors: Grimm Daniel , Heeg Maximilian , Thimme Robert
Published: September 2012

Owing to the major limitations of current antiviral therapies in HBV (hepatitis B virus) infection, there is a strong need for novel therapeutic approaches to this major health burden. Stimulation of the host's innate and adaptive immune responses in a way that results in the resolution of viral infection is a promising approach. A better understanding of the virus–host interaction in acute and chronic HBV infection revealed several possible novel targets for antiviral immunotherapy. In the present review, we will discuss the current state of the art in HBV immunology and illustrate how control of infection could be achieved by immunotherapeutic interventions.
Factors affecting levels of urinary albumin excretion in the general population of Spain: the Di@bet.es study
Authors: Gutiérrez-Repiso Carolina , Rojo-Martínez Gemma , Soriguer Federico , García-Fuentes Eduardo , Vendrell Joan , Vázquez José A. , Valdés Sergio , Urrutia Inés , Serrano-Rios Manuel , Pascual-Manich Gemma , Ortega Emilio , Mora-Peces Inmaculada , Menéndez Edelmiro , Martínez-Larrad M. Teresa , López-Alba Alfonso , Gutiérrez Galder , Gomis Ramón , Goday Albert , Girbés Juan , Gaztambide Sonia , Franch Josep , Delgado Elías , Catalá Miguel , Castell Conxa , Castaño Luis , Casamitjana Roser , Carmena Rafael , Calle-Pascual Alfonso , Bordiú Elena , Bosch-Comas Anna
Published: September 2012

The present study was undertaken to examine the prevalence of urinary ACR (albumin/creatinine ratio) >30 mg/g and the associated clinical and environmental factors in a representative sample of the population of Spain. Di@bet.es study is a national, cross-sectional population-based survey conducted in 2009–2010. Clinical, metabolic, socio-demographic, anthropometric data and information about lifestyle habit were collected. Those subjects without KDM (known diabetes mellitus) were given an OGTT (oral glucose tolerance test). Albumin and creatinine were measured in a urinary sample and ACR was calculated. The population prevalence of ACR >30 mg/g was 7.65% (adjusted for sex and age). The prevalence of ACR >30 mg/g increased with age (P<0.001). Subjects with carbohydrate metabolism disorders had a greater prevalence of ACR >30 mg/g but after being adjusted for age, sex and hypertension, was significant only in those subjects with UKDM (unknown diabetes mellitus) {OR (odd ratio), 2.07 [95% CI (confidence interval), 1.38–3.09]; P<0.001] and KDM [OR, 3.55 (95% CI, 2.63–4.80); P<0.001]. Prevalence of ACR >30 mg/g was associated with hypertension [OR, 1.48 (95% CI, 1.12–1.95); P=0.001], HOMA-IR (homoeostasis model assessment of insulin resistance) [OR, 1.47 (95% CI, 1.13–1.92); P≤0.01], metabolic syndrome [OR, 2.17 (95% CI, 1.72–2.72); P<0.001], smoking [OR, 1.40 (95% CI, 1.06–1.83); P≤0.05], physical activity [OR, 0.68 (95% CI, 0.54–0.88); P≤0.01] and consumption of fish [OR, 0.38 (95% CI, 0.18–0.78); P≤0.01]. This is the first study that reports the prevalence of ACR >30 mg/g in the Spanish population. The association between clinical variables and other potentially modifiable environmental variables contribute jointly, and sometimes interactively, to the explanation of prevalence of ACR >30 mg/g. Many of these risk factors are susceptible to intervention.
NF-κB1 deficiency stimulates the progression of non-alcoholic steatohepatitis (NASH) in mice by promoting NKT-cell-mediated responses
Authors: Locatelli Irene , Sutti Salvatore , Vacchiano Marco , Bozzola Cristina , Albano Emanuele
Published: September 2012

Growing evidence indicates that NF-κB (nuclear factor κB) activation contributes to the pathogenesis of NASH (non-alcoholic steatohepatisis). Among the NF-κB subunits, p50/NF-κB1 has regulatory activities down-modulating NF-κB-mediated responses. In the present study, we investigated the effects of NF-κB1 deficiency on the progression of NASH induced by feeding mice on an MCD (methionine/choline-deficient) diet. Following 4 weeks on the MCD diet, steatosis, ALT (alanine aminotransferase) release, hepatocyte apoptosis, lobular inflammation and TNFα (tumour necrosis factor α) production were higher in NF-κB1−/− (NF-κB1-knockout) mice than in WT (wild-type) mice. NF-κB1−/− mice also showed appreciable centrilobular collagen deposition, an increased number of activated hepatic stellate cells and higher type-I procollagen-α and TIMP-1 (tissue inhibitor of metalloproteases-1) mRNA expression. Although NF-κB p50 homodimers regulate macrophage activation, the number of hepatic macrophages and liver mRNAs for iNOS (inducible NO synthase), IL (interleukin)-12p40, CCL2 (CC chemokine ligand 2) and CXCL10 (CXC chemokine ligand 10) were comparable in the two strains. NASH was associated with an increase in liver infiltrating T-cells that was more evident in MCD-fed NF-κB1−/− than in similarly treated WT mice. Flow cytorimetry showed that T-cell recruitment involved effector CD8+ T-cells without changes in the helper CD4+ T-cell fraction. Furthermore, although NASH lowered hepatic NKT cells [NK (natural killer) T-cells] in WT mice, the NKT cell pool was selectively increased in the livers of MCD-fed NF-κB1−/− mice. Such NKT cell recruitment was associated with an early overexpression of IL-15, a cytokine controlling NKT cell survival and maturation. In the livers of MCD-fed NF-κB1−/− mice, but not in those of WT littermates, we also observed an up-regulation in the production of NKT-related cytokines IFN (interferon)-γ and osteopontin. Taken together, these results indicate that NF-κB1 down-modulation enhanced NASH progression to fibrosis by favouring NKT cell recruitment, stressing the contribution of NKT cells in the pathogenesis of NASH.
Antenatal Diagnosis of a Giant Fetal Hepatic Hemangioma and Treatment with Maternal Corticosteroid
Authors: Schmitz R. , Heinig J. , Klockenbusch W. , Kiesel L. , Steinhard J.
Published: September 2012

Initial diagnosis of a fetal hemangioendothelioma of the liver was made at 28 + 1 weeks of gestation. Due to the growth of the liver tumor and increasing fetal cardiac load, 4 mg dexamethasone were administered daily from 32 + 3 to 36 + 6 weeks of gestation. With this medication the fetal cardiac load was unchanged and slow further increase of the tumor size occurred. At 36 + 6 weeks of gestation, a primary caesarean section was performed due to fetal heart decompensation and pathological CTG. Maternal therapy with dexamethasone should be considered for antenatally detected Giant Fetal Hepatic Hemangioma.