bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Inhibition of Steroidogenic Enzymes by Ketoconazole in Rat Ovary Cells
Authors: Gal Michael , Orly Joseph
Published: February 2014

Objective

Ketoconazole (KCZ) is an anti-fungal agent extensively used for clinical applications related to its inhibitory effects on adrenal and testicular steroidogenesis. Much less information is available on the effects of KCZ on synthesis of steroid hormones in the ovary. The present study aimed to characterize the in situ effects of KCZ on steroidogenic enzymes in primary rat ovary cells.

Methods

Following the induction of folliculogenesis in gonadotropin treated rats, freshly prepared ovarian cells were incubated in suspension for up to four hours while radiolabeled steroid substrates were added and time dependent generation of their metabolic products was analyzed by thin layer chromatography (TLC).

Results

KCZ inhibits the P450 steroidogenic enzymes in a selective and dose dependent manner, including cholesterol side-chain cleavage cytochrome P450 (CYP11A1/P450scc), the 17α-hydroxylase activity of CYP17A1/P450c17, and CYP19A1/P450arom, with IC50 values of 0.3, 1.8, and 0.3 μg/mL (0.56, 3.36, and 0.56 μM), respectively. Unaffected by KCZ, at 10 μg/mL, were the 17,20 lyase activity of CYP17A1, as well as five non-cytochrome steroidogenic enzymes including 3β-hydroxysteroid dehydrogenase-δ5-4 isomerase type 1 (3βHSD1), 5α-reductase, 20α-hydroxysteroid dehydrogenase (20α-HSD), 3α-hydroxysteroid dehydrogenase (3α-HSD), and 17β-hydroxysteroid dehydrogenase type 1 (17HSD1).

Conclusion

These findings map the effects of KCZ on the ovarian pathways of progestin, androgen, and estrogen synthesis. Hence, the drug may have a potential use as an acute and reversible modulator of ovarian steroidogenesis in pathological circumstances.
The beginnings of dairying as practised by pastoralists in ‘green’ Saharan Africa in the 5th millennium BC
Authors: Dunne Julie , Evershed Richard P. , Cramp Lucy , Bruni Slivia , Biagetti Stefano , Di Lernia Savino
Published: February 2014

Previous research has identified the antiquity and chronology of dairying practices as beginning in the Near East and its subsequent spread across Europe. In the Libyan Sahara, archaeological evidence, confirmed by the remarkable rock art depicting cattle herding, together with faunal evidence, also suggests an early inception of dairying practices in North Africa and the formation of an independent ‘secondary products’ economy by mobile pastoral groups. In this paper, we elaborate on the first unequivocal chemical evidence, based on the δ13C and Δ13C values of the major fatty acids of milk fat, for the adoption of dairying practices by prehistoric Saharan African people in the fifth millennium BC.
A new look at old material: ceramic petrography and Neo\Eneolithic pottery traditions in the eastern Ljubljansko barje, Slovenia
Authors: Žibrat Gašparič Andreja
Published: February 2014

In this article, a new look at old material, pottery, is presented, as the technology and operational sequences of pottery from the Neolithic and Eneolithic in Slovenia is mostly understudied. Here, the focus is on 5th and 4th millennia BC artefacts from the eastern part of Ljubljansko barje and sites, such as Resnikov prekop, Maharski prekop and Breg near πkofljica. The pottery was studied with a hand lens and petrographically, using an optical polarising microscope. The results were then compared to analyses of locally gathered clays and sediments. Pottery traditions at Resnikov prekop and Breg were different from those at Maharski prekop, although the vessels from all three sites were produced locally and mostly made from local material, but with different recipes or fabrics. The selection of raw material, the shaping and decorating of pots, their firing and use were probably more related to different traditions and individual choices of potters at these sites than to purely technological choices.
Pietrele in the Lower Danube region: integrating archaeological, faunal and environmental investigations
Authors: Benecke Norbert , Hansen Svend , Nowacki Dirk , Reingruber Agathe , Ritchie Kenneth , Wunderlich Jürgen
Published: February 2014

The c. 9m high tell-settlement of Pietrele-Magura Gorgana, situated close to the Danube river, is one of the westernmost sites of the Kod∫adermen-Gumelnita-Karanovo VI cultural complex that spread over the whole Westpontic region during the 5th millennium BC. Until recently tells were equated with the site when, in fact, they represent only the outstanding part of a far more complex settlement system as we now know from Pietrele thanks to geomagnetic prospections and subsequent excavations. People living on the tell, together with the inhabitants from the flat area around it, formed a vast community that must have had a strong impact on its habitat and, vice-versa, was strongly affected by the immediate surroundings. During the settlement period a lake covered huge parts of the floodplain. It provided not only a considerable part of the diet, but ensured, through the direct access to the main river, continuous and extensive over-regional exchange.
Neolithic and Chalcolithic settlement patterns in central Moldavia (Romania)
Authors: Brigand Robin , Weller Olivier
Published: February 2014

Despite a long tradition of studies of the Moldavian Neolithic and Chalcolithic cultures, the analysis of the territorial behaviour of human communities remains underexploited. This work combines concepts used in landscape archaeology with the potential of the Geographic Information System (GIS) to mobilise archaeological artefacts in a large-scale setting and for many thematic purposes. This paper aims to compare the spatial and temporal distributions of archaeological evidence in central Moldavia. Applying integrated approaches through GIS analysis, it explores the natural, economic and social phenomena involved in territorial trajectories during the Later Pre- history (6000–3500 BC). In the chronological framework of the Star≠evo-Cris, Linear Pottery, Precucuteni and Cucuteni cultures, different types of spatial analysis are computed in order to underline territorial control and supply strategies in an area well known for its density of its fortified settlements, extremely rich soils and abundance of salt springs.
Interdisciplinary studies of the Cis-Ural Neolithic (Upper Kama basin, Lake Chashkinskoe): Palaeoecological aspects
Authors: Lychagina Evgeniia , Zaretskaya Nataliya , Chernov Alexey , Lapteva Elena
Published: February 2014

In this paper we present preliminary results of the first palaeoecological investigations in the Cis-Ural region. This was an area of intensive Neolithic occupation of fluvial landscapes within the basin of the Upper Kama River, the largest river in the area. We selected the area of Lake Chashkinskoe as a key region, where around 10 sites have been found on the remains of the fluvial terraces of the Kama River. We used palaeochannel analysis, radiocarbon dating, and palynology for past landscape reconstruction.
Deciphering Later Neolithic stamp seal imagery of Northern Mesopotamia
Authors: Atakuman Çigdem
Published: February 2014

Stamps, pendants and related image bearing objects of the Near Eastern Neolithic are commonly treated as markers of property control and as precursors of writing. Through a basic stylistic analysis of image and shape relations, this study focuses on material from later 7th and the 6th millennium BC Northern Mesopotamian sites in an attempt to understand the symbolic role of stamps within the wider context of social practice. I suggest that the stamps and pendants may have been objects that elaborated on their user’s identity in various spheres of social membership. More significantly, these objects may have introduced a new discursive field through which personal iden- tities and community structures began to be redefined with reference to male sexuality. This interpretation is demonstrated by the dominance of phallic imagery within the stamp assemblages of the time period and the links built between these phallic images and the remaining stamp corpus which is composed of powerful imagery surviving from the earlier Neolithic of the region.
The necklace from the Strážnice site in the Hodonín district (Czech Republic). A contribution on the subject of Spondylus jewellery in the Neolithic
Authors: Gardelková-Vrtelová Anna , Golej Marián
Published: February 2014

The study refers to the issue of shell artefacts in the Early Neolithic and highlights the importance of identifying the correct genus and species of the raw material used. The subject of the study is an older find of a necklace, which had not been subjected to any analysis of species identi- fication in the past. The shell material of the necklace was examined by ‘microstructural analysis’. This article also questions the age of the necklace and the possibilities of it having been reconstructed.
Managing raw materials in Vinča culture: a case study of osseous raw materials from Vitkovo
Authors: Vitezović Selena , Bulatović Jelena
Published: February 2014

In analyses of material recovered from archaeological sites, a dichotomy often exists between ‘specialist’ and ‘archaeological’ studies. This is especially noticeable in the case of faunal remains and bone artefacts. Bone artefacts are sometimes treated separately from fauna with emphasis on typological data, or they can be left within the fauna with only a remark on ‘other taphonomic traces’, thereby overlooking technological features of these artefacts. However, bone industry provides excellent insight into technological choices regarding raw material exploitation, since the availability and mechanical properties of specific materials can be directly observed. In this paper we tried to link bone artefacts with other faunal remains on the basis of a case study of the Vinča culture site at Vitkovo with a special emphasis on the relations between butchering techniques and raw material selection and the relations between the economically most important species and the bones most commonly used in tool manufacture.
New Pre-Pottery Neolithic sites and cult centres in the Urfa Region
Authors: Güler Gül , Çelik Bahattin , Güler Mustafa
Published: February 2014

The present study assesses the sites and the corresponding artefacts that were recently discovered during cultural inventory studies in the Urfa region in south-eastern Turkey. The studies were conducted at PPN sites located at Herzo Tepe, Basaran Höyük and Kocanizam, Taslı Tepe and  ̇Inanlı Tepe within the borders of Viransehir and Siverek boroughs; the already known site at Sefer Tepe is also re-examined. The sites extend in a north-south direction and were founded within a 3–5km distance, and they exhibit unique characteristics for this region. Recently discovered sites are compared to already known PPN sites in the region to reveal similar features and characteristics. In particular, the article elaborates similarities and discrepancies between sites with T-shaped pillars and sites with circular structures. The recently discovered sites demonstrate that the pillar tradition is predominant in the region and that the settlements have a distinct layout.
14C dates and stratigraphy: reconsidering the sequences at Moverna vas (Bela Krajina, southeastern Slovenia)
Authors: Sraka Marko
Published: February 2014

Recently obtained AMS 14C dates and the stratigraphic matrix from the Moverna vas site show inconsistencies in the upper part of the stratigraphic sequence. The Bayesian approach to chronological modeling in the OxCal program is used in the paper to present the calendar chronology of Neolithic and Eneolithic settlement phases at the site and to propose a revision of the upper part of the stratigraphic sequence, also partly supported by a typological comparison of a pottery vessel from one of the 14C dated contexts.
The bioarchaeology of the Neolithic transition: evidence of dental pathologies at Lepenski Vir (Serbia)
Authors: Radović Marija , Stefanović Sofija
Published: February 2014

The Neolithic transition affected human biology, which is visible as a series of inter- related skeletal and dental pathological conditions. The population of Lepenski vir culture, which inhabited the region of the Danube Gorges between 9500–5500 BC, also went through the neolithisa- tion process. In this study, the dental pathological conditions of 32 adult individuals from the Lepenski Vir site were examined for the incidence of enamel hypoplasia, the rate of dental wear, dental caries and ante-mortem tooth loss. The results indicate changes in biology and diet of this population in the Neolithic which were associated with the introduction of non-local identities in the region.
Retrieval of the Eyjafjallajökull volcanic aerosol optical and microphysical properties from POLDER/PARASOL measurements
Authors: Waquet F. , Peers F. , Goloub P. , Ducos F. , Thieuleux F. , Derimian Y. , Riedi J. , Chami M. , Tanré D.
Published: February 2014

Abstract. Total and polarized radiances provided by the Polarization and Directionality of Earth Reflectances (POLDER) satellite sensor are used to retrieve the microphysical and optical properties of the volcanic plume observed during the Eyjafjallajökull volcano eruption in 2010, over cloud-free and cloudy ocean scenes. We selected two plume conditions, fresh aerosols near the sources (three cases) and a downwind volcanic plume observed over the North Sea 30 h after its injection into the atmosphere (aged aerosols). In the near-source conditions, the aerosol properties depend on the distance to the plume. Within the near-source plume, aerosols are mainly non-spherical and in the coarse mode with an effective radius equal to 1.75 (±0.25) μm and an Ångström exponent (AE) close to 0.0. Far from the plume, in addition to the coarse mode, there are particles retrieved in the accumulation mode, suggesting a mixture of sulfate aerosols and volcanic dust, resulting in an AE around 0.8. The properties of the aerosols also depend on whether the plume is fresh or aged. For the downwind (aged) plume, if non-spherical coarse particles as well as some fine mode particles are retrieved, the AE is higher, around ~0.4. In addition, rather low values for the real part of the refractive index (RR) were retrieved for the fresh plume (1.38 < RR < 1.48). Single scattering albedo (SSA) values ranging between 0.92 and 0.98 were retrieved over some parts of the near-source plume; despite the low accuracy of our retrievals, the derived SSA values suggest that the ash particles are rather absorbing. To consider the particle shape, a combination of spheroid models was used. Although the employed model enabled accurate modeling of the POLDER signal in the case of non-spherical ash, our approach failed to model the signal over the optically thickest parts of the near-source plume. The most probable reason for this is the presence of ice crystals within the plume. For the aerosol above clouds (AAC) scenes, polarized measurements allowed the retrieval of the optical thickness (OT) and the AE of optically thin volcanic ash. We found that all the cloud parameters retrieved by passive sensors were biased due to the presence of the elevated volcanic plumes. Finally, thermal infrared measurements were used to identify the type of multilayer scene (cirrus clouds or volcanic dust above liquid clouds) and the retrieval method also provided the OT of thin cirrus layers above the clouds near Iceland.
One-year observations of carbonaceous and nitrogenous components and major ions in the aerosols from subtropical Okinawa Island, an outflow region of Asian dusts
Authors: Kunwar B. , Kawamura K.
Published: February 2014

Abstract. Ambient aerosol samples (TSP, n = 50) were collected for 12 months at subtropical Okinawa Island, Japan, an outflow region of Asian dusts in the western North Pacific and analysed for organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), water-soluble total nitrogen (WSTN), water-soluble organic nitrogen (WSON) and major ions to better understand the formation and transformation of East Asian aerosols during long-range atmospheric transport. Concentration ranges of these components are; OC: 0.76–7.1 μg m−3 (av. 1.7 ± 1.0 μg m−3), EC: 0.07–0.96 μg m−3 (0.28 ± 0.19 μg m−3), WSOC: 0.27–1.9 μg m−3 (0.73 ± 0.38 μg m−3), WSTN: 0.77 to 3.0 μg m−3 (0.58 ± 0.46 μg m−3) and WSON: 0.0–2.2 μg m−3 (0.12 ± 0.23 μg m−3). Higher OC concentrations were obtained in active biota seasons; spring (av. 2.4 μg m−3) and summer (1.8 μg m−3). EC and WSOC concentrations maximized in spring (av. 0.41 μg m−3 and 0.95 μg m−3, respectively) followed by winter (0. 70 and 0.90 μg m−3) whereas they became lowest in summer (0.19 and 0.52 μg m−3). In contrast, WSTN concentrations were highest in winter (0.86 μg m−3) and lowest in summer (0.37 μg m−3) and autumn (0.34 μg m−3). Concentrations of WSON are higher in early summer (av. 0.26 μg m−3) due to the emission from marine biota. The high ratios of OC / EC (av. 7.6) and WSOC / OC (44%) suggest a secondary formation of organic aerosols. Strong correlation between OC and MSA- (0.81) in spring suggests that springtime aerosols are influenced by additional marine and terrestrial biogenic sources. The positive correlation of Ca2+ and TSP in spring (r = = 0.81) demonstrates a significant contribution of Asian dust whereas high abundances of NO3- and nss-SO42- in winter suggest an important contribution from anthropogenic sources including biomass burning, vehicular emission and coal combustion. NH4-N/WSTN ratios peaked in winter (0.56), indicating a significant contribution of biomass burning to WSTN in cold season. In contrast, higher NO3-N/WSTN ratio in spring than winter suggests that the atmospheric transport of vehicular emissions maximizes in spring. Correlation analyses of major ions suggest that NH4+ and Ca2+ play major role in the neutralization of acidic aerosols forming NH4HSO4, (NH4)2SO4 and CaSO4.
A sea spray aerosol flux parameterization encapsulating wave state
Authors: Ovadnevaite J. , Manders A. , de Leeuw G. , Ceburnis D. , Monahan C. , Partanen A.-I. , Korhonen H. , O'Dowd C. D.
Published: February 2014

Abstract. A new sea spray source function (SSSF), termed Oceanflux Sea Spray Aerosol or OSSA, was derived based on in-situ sea spray aerosol measurements along with meteorological/physical parameters. Submicron sea spray aerosol fluxes derived from particle number concentration measurements at the Mace Head coastal station, on the west coast of Ireland, were used together with open-ocean eddy correlation flux measurements from the Eastern Atlantic Sea Spray, Gas Flux, and Whitecap (SEASAW) project cruise. In the overlapping size range, the data for Mace Head and SEASAW were found to be in a good agreement, which allowed deriving the new SSSF from the combined dataset spanning the dry diameter range from 15 nm to 6 μm. The OSSA source function has been parameterized in terms of five lognormal modes and the Reynolds number instead of the more commonly used wind speed, thereby encapsulating important influences of wave height, wind history, friction velocity, and viscosity. This formulation accounts for the different flux relationships associated with rising and waning wind speeds since these are included in the Reynolds number. Furthermore, the Reynolds number incorporates the kinematic viscosity of water, thus the SSSF inherently includes dependences on sea surface temperature and salinity. The temperature dependence of the resulting SSSF is similar to that of other in-situ derived source functions and results in lower production fluxes for cold waters and enhanced fluxes from warm waters as compared with SSSF formulations that do not include temperature effects.
Uptake of HO2 radicals onto Arizona Test Dust aerosols
Authors: Matthews P. S. J. , Baeza-Romero M. T. , Whalley L. K. , Heard D. E.
Published: February 2014

Abstract. Uptake coefficients for HO2 radicals onto Arizona Test Dust (ATD) aerosols were measured at room temperature and atmospheric pressure using an aerosol flow tube and the sensitive Fluorescence Assay by Gas Expansion (FAGE) technique, enabling HO2 concentrations in the range 3–10 × 108 molecule cm−3 to be investigated. The uptake coefficients were measured as 0.031 ± 0.008 and 0.018 ± 0.006 for the lower and higher HO2 concentrations, respectively, over a range of relative humidities (5–76%). A time dependence for the HO2 uptake onto the ATD aerosols was observed, with larger uptake coefficients observed at shorter reaction times. The combination of time and HO2 concentration dependencies suggest either the partial saturation of the dust surface or that a chemical component of the dust is partially consumed whilst the aerosols are exposed to HO2. A constrained box model is used to show that HO2 uptake to dust surfaces may be an important loss pathway of HO2 in the atmosphere.
Comparison of the predictions of two road dust emission models with the measurements of a mobile van
Authors: Kauhaniemi M. , Stojiljkovic A. , Pirjola L. , Karppinen A. , Härkönen J. , Kupiainen K. , Kangas L. , Aarnio M. A. , Omstedt G. , Denby B. R. , Kukkonen J.
Published: February 2014

Abstract. The predictions of two road dust suspension emission models were compared with the on-site mobile measurements of suspension emission factors. Such a quantitative comparison has not previously been reported in the reviewed literature. The models used were the Nordic collaboration model NORTRIP (NOn-exhaust Road TRaffic Induced Particle emissions) and the Swedish–Finnish FORE model (Forecasting Of Road dust Emissions). These models describe particulate matter generated by the wear of road surface due to traction control methods and processes that control the suspension of road dust particles into the air. An experimental measurement campaign was conducted using a mobile laboratory called SNIFFER, along two selected road segments in central Helsinki in 2007 and 2008. The suspended PM10 concentration was measured behind the left rear tyre and the street background PM10 concentration in front of the van. Both models reproduced the measured seasonal variation of suspension emission factors fairly well during both years at both measurement sites. However, both models substantially under-predicted the measured emission values. The results indicate that road dust emission models can be directly compared with mobile measurements; however, more extensive and versatile measurement campaigns will be needed in the future.
Importance of aerosols for annual lightning production at global scale
Authors: Venevsky S.
Published: February 2014

Abstract. Lightning production is described using thermodynamic hypotheses mainly according to convective activity in the atmosphere. However, existing formal thermodynamic descriptions are unable to fully explain the profound difference in the flash rate between tropical Africa and South America and between land and ocean. Aerosols are shown to be regulators of lightning in regional studies, but their influence on lightning production at the global scale is not described. I analyzed spatial patterns of the satellite annual global flash rate and simulated, annually averaged cloud condensation nuclei (CCN) distribution and found consistent positive correlation between them for land, ocean and continents. I developed a simple model of lightning production that is based solely on an aerosol hypothesis. The central premise of this model is that concentration of graupel pellets and concentration of ice crystals, which both determine flash rate, are monotonically increasing by CCN concentration up to a critical value (around 2000 cm−3). However, ice crystal concentration falls rapidly after the threshold due to lowering in the number of large cloud droplets effective for rime-splintering ice multiplication. Comparison of the model with a model of the flash rate based on thermodynamic hypotheses demonstrates that the aerosol hypothesis explains the global annual spatial distribution of lightning production consistently better over land and over oceans. My results emphasize importance of aerosols for lightning production and point to the existence of a global aerosol-lightning feedback, which affects both the climate system and the land surface.
Hydrometor classification from 2 dimensional videodisdrometer data
Authors: Grazioli J. , Tuia D. , Monhart S. , Schneebeli M. , Raupach T. , Berne A.
Published: February 2014

Abstract. This paper presents a hydrometeor classification technique based on two-dimensional video disdrometer (2DVD) data. The method provides an estimate of the dominant hydrometeor type falling over time intervals of 60 s during precipitation, using as input the statistical behavior of a set of particle descriptors, calculated for each particle image. The employed supervised algorithm is a support vector machine (SVM), trained over precipitation time steps labeled by visual inspection. In this way, 8 dominant hydrometeor classes could be discriminated. The algorithm achieves accurate classification performances, with median overall accuracies (Cohen's K) of 90% (0.88), and with accuracies higher than 84% for each hydrometeor class.
The added value of a visible channel to a geostationary thermal infrared instrument to monitor ozone for air quality
Authors: Hache E. , Attié J.-L. , Tourneur C. , Ricaud P. , Coret L. , Lahoz W. A. , El Amraoui L. , Josse B. , Hamer P. , Warner J. , Liu X. , Chance K. , Höpfner M. , Spurr R. , Natraj V. , Kulawik S. , Eldering A. , Orphal J.
Published: February 2014

Abstract. Ozone is a tropospheric pollutant and plays a key role in determining the air quality that affects human wellbeing. In this study, we compare the capability of two hypothetical grating spectrometers onboard a geostationary (GEO) satellite to sense ozone in the lowermost troposphere (surface and the 0–1 km column). We consider one week during the Northern Hemisphere summer simulated by a chemical transport model, and use the two GEO instrument configurations to measure ozone concentration (1) in the thermal infrared (GEO TIR) and (2) in the thermal infrared and the visible (GEO TIR+VIS). These configurations are compared against each other, and also against an ozone reference state and a priori ozone information. In a first approximation, we assume clear sky conditions neglecting the influence of aerosols and clouds. A number of statistical tests are used to assess the performance of the two GEO configurations. We consider land and sea pixels and whether differences between the two in the performance are significant. Results show that the GEO TIR+VIS configuration provides a better representation of the ozone field both for surface ozone and the 0–1 km ozone column during the daytime especially over land.
Long-term changes in thermospheric composition inferred from a spectral analysis of ionospheric F-region data
Authors: Scott C. J. , Stamper R. , Rishbeth H.
Published: February 2014

Abstract. A study of ionospheric data recorded at Slough/Chilton, UK, from 1935 to 2012, has revealed long-term changes in the relative strength of the annual and semi-annual variability in the ionospheric F2 layer critical frequencies. Comparing these results with data from the southern hemisphere station at Stanley in the Falkland Islands between 1945 and 2012 reveals a trend that appears to be anti-correlated with that at Chilton. The behaviour of foF2 is a function of thermospheric composition and so we argue that the observed long-term changes are driven by composition change. The ionospheric trends share some of their larger features with the trend in the variability of the aa geomagnetic index. Changes to the semi-annual/annual ratio in the Slough/Chilton and Stanley data may therefore be attributable to the variability in geomagnetic activity which controls the average latitudinal extent of the auroral ovals and subsequent thermospheric circulation patterns. Changes in ionospheric composition or thermospheric wind patterns are known to influence the height of the F2 layer at a given location. Long-term changes to the height of the F2 layer have been used to infer an ionospheric response to greenhouse warming. We suggest that our observations may influence such measurements and since the results appear to be dependent on geomagnetic longitude, this could explain why the long-term drifts observed in F2 layer height differ between locations.
Sample size matters: investigating the effect of sample size on a logistic regression susceptibility model for debris flows
Authors: Heckmann T. , Gegg K. , Gegg A. , Becht M.
Published: February 2014

Abstract. Predictive spatial modelling is an important task in natural hazard assessment and regionalisation of geomorphic processes or landforms. Logistic regression is a multivariate statistical approach frequently used in predictive modelling; it can be conducted stepwise in order to select from a number of candidate independent variables those that lead to the best model. In our case study on a debris flow susceptibility model, we investigate the sensitivity of model selection and quality to different sample sizes in light of the following problem: on the one hand, a sample has to be large enough to cover the variability of geofactors within the study area, and to yield stable and reproducible results; on the other hand, the sample must not be too large, because a large sample is likely to violate the assumption of independent observations due to spatial autocorrelation. Using stepwise model selection with 1000 random samples for a number of sample sizes between n = 50 and n = 5000, we investigate the inclusion and exclusion of geofactors and the diversity of the resulting models as a function of sample size; the multiplicity of different models is assessed using numerical indices borrowed from information theory and biodiversity research. Model diversity decreases with increasing sample size and reaches either a local minimum or a plateau; even larger sample sizes do not further reduce it, and they approach the upper limit of sample size given, in this study, by the autocorrelation range of the spatial data sets. In this way, an optimised sample size can be derived from an exploratory analysis. Model uncertainty due to sampling and model selection, and its predictive ability, are explored statistically and spatially through the example of 100 models estimated in one study area and validated in a neighbouring area: depending on the study area and on sample size, the predicted probabilities for debris flow release differed, on average, by 7 to 23 percentage points. In view of these results, we argue that researchers applying model selection should explore the behaviour of the model selection for different sample sizes, and that consensus models created from a number of random samples should be given preference over models relying on a single sample.
Simulating the Greenland ice sheet under present-day and palaeo constraints including a new discharge parameterization
Authors: Calov R. , Robinson A. , Perrette M. , Ganopolski A.
Published: February 2014

Abstract. In this paper, we propose a new sub-grid scale parameterization for the ice discharge into the ocean through outlet glaciers and inspect the role of different observational and palaeo constraints for the choice of an optimal set of model parameters. This parameterization was introduced into the polythermal ice-sheet model SICOPOLIS, which is coupled to the regional climate model of intermediate complexity REMBO. Using the coupled model, we performed large ensemble simulations over the last two glacial cycles. We exploit two major parameters: a melt parameter in the surface melt scheme of REMBO and an ice discharge parameter in our parameterization of ice discharge. Our constraints are the present-day Greenland ice sheet surface elevation, surface mass balance partition (ratio between ice discharge and total precipitation) and the Eemian interglacial elevation drop relative to present-day in the vicinity of the NEEM ice core. We show that the ice discharge parameterization enables us to simulate both the correct ice-sheet shape and mass balance partition at the same time without explicitly resolving the Greenland outlet glaciers. For model verification, we compare simulated total and sectoral ice discharge with those from other findings, including observations. For the model versions, which are inside the range of observational and palaeo constraints, our simulated Greenland ice sheet contribution to Eemian sea level rise relative to present-day amounts to 1.4 m on average (in the range of 0.6 and 2.5 m).
A high-resolution bedrock map for the Antarctic Peninsula
Authors: Huss M. , Farinotti D.
Published: February 2014

Abstract. Assessing and projecting the dynamic response of glaciers on the Antarctic Peninsula to changed atmospheric and oceanic forcing requires high-resolution ice thickness data as an essential geometric constraint for ice flow models. Here, we derive a complete bedrock data set for the Antarctic Peninsula north of 70° S on a 100 m grid. We calculate distributed ice thickness based on surface topography and simple ice dynamic modelling. Our approach is constrained with all available thickness measurements from Operation IceBridge and gridded ice flow speeds for the entire study region. The new data set resolves the rugged subglacial topography in great detail, indicates deeply incised troughs, and shows that 34% of the ice volume is grounded below sea level. The Antarctic Peninsula has the potential to raise global sea level by 71 ± 5 mm. In comparison to Bedmap2, covering all Antarctica on a 1 km grid, a significantly higher mean ice thickness (+48%) is found.
The Use of Bean Sprout Extract as Supplement for the Growth of Plaintain Unti Sayang (Musa paradisiaca L.) by Tissue Culture
Authors: Jufri Nirwana , Abdullah Dr. , Susanti Devi
Published: February 2014

One of the problems in plaintain development is on the plant breeding that has been conducted convensionally by using seedlings, so that it requires time and wide field, different treatment, and potentially brings pests and deseases. The bean sprout extract is potentially useful in improving the explant growth quality of plaintain by tissue culture. This study aims to know the influence of bean sprout extract concentration as supplement in tissue culture media upon the explant growth of plaintain Unti sayang (Musa paradisiaca L). There are 4 dosages of bean sprout extract as control. The data was analyzed by using ANOVA and was continued by using BNJ test. The result of the experiment shows that the bean sprout extract influences significatly on the plantlets height, leaf number, root length, and root number. The dosage of 100 g/l and 200 g/l bean sprout extracts provide the best result on the experimenting component of plantlet height, leaf number, root length, and root number. Meanwhile, the experimenting component of leaf number and the wet weight of the plantlets provide the best result on MS without any addition of bean sprout extract.
The potential for bridging: HIV status awareness and risky sexual behaviour of injection drug users who have non‐injecting permanent partners in Ukraine
Authors: Mazhnaya Alyona , Andreeva Tatiana I , Samuels Steve , DeHovitz Jack , Salyuk Tetyana , McNutt Louise‐Anne
Published: February 2014

Objective

To quantify potential bridging of HIV transmission between the injection drug using subpopulation to the non‐injection drug using population through unprotected heterosexual sex.

Design

Secondary analysis of cross‐sectional data.

Methods

A sub‐sample of participants who reported having a permanent partner who are not injection drug users and have not injected drugs in the past (N=1379) was selected from a survey implemented in 26 Ukrainian cities in 2011. This study evaluates the association between consistent condom use and awareness of HIV status as measured by rapid testing during the study (known/unknown HIV+, known/unknown HIV− and undetermined) among a sub‐sample of male injection drug users (IDUs) who have a non‐injecting permanent partner. Poisson regression, with robust variance estimates, was utilized to identify associations while adjusting for other factors.

Results

Reported consistent condom use varied between 15.5% (unknown HIV−) and 37.5% (known HIV+); average use was 19.3%. In multivariate analysis, males who were aware of their HIV+ status were more likely to report recent consistent condom use compared to those who were unaware of their HIV+ status. This association remains after adjustment for age, region, education level, years of injection, alcohol use, self‐reported primary drug use and being an NGO client (prevalence ratio=1.65; 95% CI 1.03–2.64). No such association was found for those who were HIV−.

Conclusions

Our results regarding HIV‐positive male IDUs reinforce previous findings that HIV testing and counselling may be an effective means of secondary prevention. Further research is needed to understand how to effectively promote safer sex behaviours for IDUs who are currently HIV−.
Highly polarized emission of the liquid crystalline conjugated polymer by controlling the surface anchoring energy
Authors: Jo Soo In , Kim Youngsik , Baek Ji-Ho , Yu Chang-Jae , Kim Jae-Hoon
Published: February 2014

We demonstrated a highly polarized organic light-emitting diode (OLED) through the enhancement of the orientational ordering of the emitting polymer with a nematic liquid crystalline (LC) phase. The highly ordered state of the conjugate polymer was obtained by thermal annealing at the nematic temperature and strong azimuthal anchoring energy of the underlying polyimide. The order parameter of the conjugate polymer was analyzed using a second-harmonic generation model and the dichroic ratio was measured to be 22 : 1. Also, we applied our optimized OLED with high optical polarizability to an effective light source for a twisted nematic LC display.
Experimental and simulation studies of neutron-induced single-event burnout in SiC power diodes
Authors: Shoji Tomoyuki , Nishida Shuichi , Hamada Kimimori , Tadano Hiroshi
Published: February 2014

Neutron-induced single-event burnouts (SEBs) of silicon carbide (SiC) power diodes have been investigated by white neutron irradiation experiments and transient device simulations. It was confirmed that a rapid increase in lattice temperature leads to formation of crown-shaped aluminum and cracks inside the device owing to expansion stress when the maximum lattice temperature reaches the sublimation temperature. SEB device simulation indicated that the peak lattice temperature is located in the vicinity of the n−/n+ interface and anode contact, and that the positions correspond to a hammock-like electric field distribution caused by the space charge effect. Moreover, the locations of the simulated peak lattice temperature agree closely with the positions of the observed destruction traces. Furthermore, it was theoretically demonstrated that the period of temperature increase of a SiC power device is two orders of magnitude less than that of a Si power device, using a thermal diffusion equation.
Fabrication and characterization of micro-inductors deposited on magnetic thin and thick layers
Authors: Désiré A. , Kriga A. , Youssouf M. , Siblini A. , Jean-Pierre C. M. , Blanc-Mignon M.-F. , Payet-Gervy B. , Piot A. , Dufeu D. , Rousseau J.-J.
Published: February 2014

This paper presents two fabrication techniques of spiral integrated inductors based on magnetic materials. For the first one, the magnetic core is a thin film deposited by RF magnetron sputtering, for the second technique the magnetic core is a thick layer of YIG obtained by micromachining. The addition of the magnetic material is expected to improve the performances of the integrated structure with electromagnetic shield. Low and high frequency equipment are used to characterize the manufactured components. A good correlation is obtained between the results by simulation and measurements for the two manufacturing techniques. These results show that the inductance increases when the thickness of the magnetic layer increases, we can double the inductance value for a thickness sufficiently high.
Isochronous information in a Greenland ice sheet radio echo sounding data set
Authors: Sime Louise C. , Karlsson Nanna B. , Paden John D. , Prasad Gogineni S.
Published: February 2014

The evaluation of ice sheet models is one of the pressing problems in the study of ice sheet dynamics. Here we examine the question of how much isochronous information is contained within the publicly available Center for Remote Sensing of Ice Sheets (CReSIS) Greenland airborne radio echo soundings data set. We identify regions containing isochronous reflectors using automatic radio echo sounding processing (ARESP) algorithms. We find that isochronous reflectors are present within 36% of the CReSIS radio echo sounding englacial data by location and 41% by total number of data. Between 1000 and 3000 m in depth, isochronous reflectors are present along more than 50% of the data set flight path. Lower volumes of cold glacial period ice also correspond with more isochronous reflectors. We find good agreement between ARESP and continuity index results, providing confidence in these findings. Ice structure data sets, based on data identified here, will be of use in evaluating ice sheet simulations and the assessment of past rates of snow accumulation.
The long‐term steady motion of Saturn's hexagon and the stability of its enclosed jet stream under seasonal changes
Authors: Sánchez‐Lavega A. , del Río‐Gaztelurrutia T. , Hueso R. , Pérez‐Hoyos S. , García‐Melendo E. , Antuñano A. , Mendikoa I. , Rojas J. F. , Lillo J. , Barrado‐Navascués D. , Gomez‐Forrellad J. M. , Go C. , Peach D. , Barry T. , Milika D. P. , Nicholas P. , Wesley A.
Published: February 2014

We investigate the long‐term motion of Saturn's north pole hexagon and the structure of its associated eastward jet, using Cassini imaging science system and ground‐based images from 2008 to 2014. We show that both are persistent features that have survived the long polar night, the jet profile remaining essentially unchanged. During those years, the hexagon vertices showed a steady rotation period of 10 h 39 min 23.01 ± 0.01 s. The analysis of Voyager 1 and 2 (1980–1981) and Hubble Space Telescope and ground‐based (1990–1991) images shows a period shorter by 3.5 s due to the presence at the time of a large anticyclone. We interpret the hexagon as a manifestation of a vertically trapped Rossby wave on the polar jet and, because of their survival and unchanged properties under the strong seasonal variations in insolation, we propose that both hexagon and jet are deep‐rooted atmospheric features that could reveal the true rotation of the planet Saturn.
Seismic anisotropy of the Archean crust in the Minnesota River Valley, Superior Province
Authors: Ferré Eric C. , Gébelin Aude , Conder James A. , Christensen Nik , Wood Justin D. , Teyssier Christian
Published: February 2014

The Minnesota River Valley (MRV) subprovince is a well‐exposed example of late Archean lithosphere. Its high‐grade gneisses display a subhorizontal layering, most likely extending down to the crust‐mantle boundary. The strong linear fabric of the gneisses results from high‐temperature plastic flow during collage‐related contraction. Seismic anisotropies measured up to 1 GPa in the laboratory, and seismic anisotropies calculated through forward‐modeling indicate ΔVP ~5–6% and ΔVS ~3%. The MRV crust exhibits a strong macroscopic layering and foliation, and relatively strong seismic anisotropies at the hand specimen scale. Yet the horizontal attitude of these structures precludes any substantial contribution of the MRV crust to shear wave splitting for vertically propagating shear waves such as SKS. The origin of the regionally low seismic anisotropy must lie in the upper mantle. A horizontally layered mantle underneath the United States interior could provide an explanation for the observed low SWS.
Plasma and energetic particle behaviors during asymmetric magnetic reconnection at the magnetopause
Authors: Lee S. H. , Zhang H. , Zong Q.‐G. , Otto A. , Sibeck D. G. , Wang Y. , Glassmeier K.‐H. , Daly P. W. , Rème H.
Published: February 2014

The factors controlling asymmetric reconnection and the role of the cold plasma population in the reconnection process are two outstanding questions. We present a case study of multipoint Cluster observations demonstrating that the separatrix and flow boundary angles are greater on the magnetosheath than on the magnetospheric side of the magnetopause, probably due to the stronger density than magnetic field asymmetry at this boundary. The motion of cold plasmaspheric ions entering the reconnection region differs from that of warmer magnetosheath and magnetospheric ions. In contrast to the warmer ions, which are probably accelerated by reconnection in the diffusion region near the subsolar magnetopause, the colder ions are simply entrained by E×B drifts at high latitudes on the recently reconnected magnetic field lines. This indicates that plasmaspheric ions can sometimes play only a very limited role in asymmetric reconnection, in contrast to previous simulation studies. Three cold ion populations (probably H+, He+, and O+) appear in the energy spectrum, consistent with ion acceleration to a common velocity.
On the presence and properties of cold ions near Earth's equatorial magnetosphere
Authors: Lee Justin H. , Angelopoulos Vassilis
Published: February 2014

Plasma flows related to magnetospheric convection or ULF waves often increase cold ions' kinetic energy sufficiently above the spacecraft potential energy so that these ions can be detected by charged particle instrumentation. Other detection methods also reveal the presence of cold ions even in the absence of flows. By applying such methods to complementary data sets obtained from particle, electric field, and magnetic field measurements by the multiple Time History of Events and Macroscale Interactions during Substorms spacecraft, we study the occurrence rates of cold ions and properties—composition, densities, and temperatures—of the dominant species (H+, He+, and O+) near the equatorial magnetosphere. As plasma flows occur at all magnetic local time (MLT) sectors, predominantly outside the plasmasphere, they enable studies of cold ion occurrence and properties as functions of geocentric distance (up to 13 RE) and MLT. Of the dominant cold ions, protons are most abundant on the dayside and coldest almost everywhere. By comparison, the heavier ions show evidence of larger abundance on the nightside and higher temperatures at most locations: median nHe+/nH+ is ≤0.1 in the afternoon, ≥1.0 on the nightside, and near 0.5 at dawn; median nO+/nH+ exceeds 1 throughout the nightside and around dawn at smaller geocentric distances but varies from 0.0 to 0.1 in the afternoon; and TO+ > THe+ everywhere. By isolating the convective particle drift component of measured ion flows, we deduce that nightside/dawn/prenoon cold ions are components of the warm plasma cloak while cold ions near noon/afternoon are likely of mixed origin, including nightside/cusp outflow, plasmaspheric plumes, and the solar wind.