bluuebunny/crossref_metadata_2025_split huggingface dataset:
”Levende studie-og læringssentra?" Rapport nr. 2: Kompetensutmaningar i tre rurala regioner
Authors: Roos Gunilla , Grepperud Gunnar , Danielsen Ådne 
Published: March 2015

<p>I den här rapporten presenteras delstudie två av tre i forskningsprojektet ”Utdanning for utvikling - studie- og læringssentrenes rolle og funksjon”. I projektet har vi studerat verksamheten i studie- och lärcentra i två rurala regioner i Norge och en i Sverige i ljuset av en samhällelig, regional och lokal kontext. En viktig utgångspunkt för vårt arbete är att för att förstå skeenden på lokal nivå måste vi ha kunskap om den samhälleliga och regionala kontext som studie- och lärcentra är inbäddade i.</p><p>Huvudfokus i den här rapporten är på utbildning i allmänhet och på högre utbildning i synnerhet i 21 kommuner, 12 i Sverige och nio i Norge. Med hjälp av tillgänglig statistik ges i den här rapporten en bild av den lokala kontext som studie- och lärcentra verkar i, i form utvecklingen av befolkningsantal, näringsliv, arbetsliv och högre utbildning. Här läggs stor vikt vid att om möjligt fånga de längre utvecklingslinjerna.</p><p>Tre centrala resultat framträder i analysen av det statistiska materialet. För det första har det skett en <em>centralisering och en regional stratifiering</em> vad gäller såväl befolkningsmässigt som andelen invånare med eller som söker sig till högre (eftergymnasial) utbildning. Vinnare är främst regioncentra och högskole- och universitetskommunerna. Sett i ett längre tidsperspektiv har centraliseringstendenserna accentuerats då ökningen av invånare med eftergymnasial utbildning samt av dem som påbörjar högre utbildning inte motsvarat den ökning som skett på riksnivå eller vid högskole- och universitetskommunerna.</p><p>För det andra framträder stora skillnader mellan män och kvinnor vad gäller såväl formell utbildningsnivå som andel högskolenybörjare i samtliga tre regioner, till kvinnornas fördel. Den positiva utveckling som skett står i stort sett kvinnorna för. Skillnaderna mellan könen har blivit större sett i ett längre tidsperspektiv.</p><p>För det tredje visar analysen att de yngre invånarna i åldern 18-24 år i en majoritet av kommunerna påbörjar högre utbildning i betydligt mindre omfattning än genomsnittet för riket. </p><p>Avslutningsvis visar analysen att de interkommunala skillnaderna sannolikt är mer uttalade än de interregionala.</p>
Triggering of earthquake swarms following the 2011 Tohoku megathrust earthquake
Authors: Umeda Koji , Asamori Koichi , Makuuchi Ayumu , Kobori Kazuo , Hama Yuki 
Published: March 2015

AbstractEarthquake swarms, often interpreted to result from fluids invading the brittle seismogenic zone, have seismicity patterns that are significantly different from an aftershock sequence. Following the Mw 9.0 Tohoku‐Oki earthquake, an unusual, shallow normal‐faulting swarm sequence occurred near the Pacific coast in the southeast Tohoku district. An integrated approach combining geophysical and geochemical methods was utilized to establish the presence of aqueous fluids around the seismic source region and their derivation. Magnetotelluric inversion defined an anomalous conductor with a width of 20 km and clearly visible to depths of more than 20 km, extending to the base of the crust. Independent geophysical observations, including seismic, strongly support the suggestion that fluid‐filled porous materials and fluids associated with slab dehydration are present in the convergent plate boundary. In order to provide geochemical constraints on the source of the fluids triggering the swarm activity, new helium isotope data were acquired from gas and water samples around the seismic source region. The observed 3He/4He ratios in these samples are significantly lower than the atmospheric value of 1.4 × 10−6, indicating that the mantle helium contribution is less than 10% of the total helium. Assuming the fluid‐triggered swarm activity, the plausible explanations for the generation of fluids are limited to the following: (1) sediment porosity reduction and from smectite‐illite and opal‐quartz reactions in the subducting deep sea sediments, (2) metamorphism of fore‐arc basin sediments, sedimentary, and/or volcanic rocks detached from the plate, or (3) dehydration reactions in the subducted oceanic crust and/or hydrated mantle below the fore‐arc mantle wedge. Geophysical and geochemical findings suggest metamorphic fluids produced by isothermal decompression of altered sediments accompanying uplift and exhumation. Owing to continued fluid production at depths of ~20 km, the fluids migrate into the seismic source region. The swarm sequence would have been triggered by stress changes associated with the Tohoku‐Oki earthquake, enhanced by vertical metamorphic fluid expulsion from the reaction zone.
Downbuilding salt stocks and sheets quantified in 3‐D analytical models
Authors: Weijermars R. , Hudec M. R. , Dooley T. P. , Jackson M. P. A. 
Published: March 2015

AbstractThe 2‐D concept of diapiric downbuilding is expanded to the third dimension. Our advanced approach shows which range of salt fluxes and sedimentation rates (time dependency included) can explain the formation of upward narrowing diapirs (previously thought of as  < 1), upward widening diapirs (~   > 1), and vertical cylindrical diapirs (~   = 1). In addition to being a nonrigorous measure, does not account for the effect of a regional slope on diapir shape during downbuilding. When a regional topographic slope is absent and lateral changes in sedimentation rate are negligible, our models confirm downbuilding diapirs always develop axisymmetric shapes. However, when the salt source lies on a regional slope, asymmetric diapirs will form. The rate of salt supply from the source and the superposed gravity flow downslope control the flow lines and shape of the advancing salt sheet. In the 2‐D gravity spreading plane, the ratio of source flow to gravity flow strengths can be characterized by a Rankine number. Obstruction of lateral spreading of salt issued from the feeder sources due to sedimentation lifts the salt from its 2‐D spreading plane, which our model simulates by superposing a velocity component normal to the sedimentation surface. We next apply the 3‐D analytical model to an offshore salt sheet in the Gulf of Mexico and analyze which conditions controlled its flow kinematics down the continental slope. Stratal cutoffs at the base of salt combined with the analytical gravity spreading model provide estimates for the dimensional flow rates and the effective viscosity of the Louann Salt.
Observations of hysteresis in the annual exchange circulation of a large microtidal estuary
Authors: Meyers Steven D. , Wilson Monica , Luther Mark. E. 
Published: March 2015

AbstractA nonlinear relation between the salinity field and the subtidal exchange circulation in the Tampa Bay estuary is demonstrated using observational data from 1999 to 2011. The data are averaged to form mean monthly climatological values of total freshwater discharge (
), axial and vertical salinity gradients, and subtidal vertical shear. Well‐known steady state solutions indicate that the exchange circulation is linearly proportional to the horizontal salinity gradient, assuming a constant vertical eddy viscosity (
). The exchange flow is found to be multivalued with respect to the horizontal salinity gradient, forming a hysteresis loop in parameter space that passes through three dynamical regimes. Regime I is relatively dry with weak salinity gradients and exchange circulation. Regime II is the wet season (June–September) in which all quantities rapidly increase. In regime III, the exchange flow persists even though
and the axial salinity gradient are again low. Gradient Richardson numbers and Simpson numbers also form a loop in parameter space with
remaining subcritical (turbulent) until the wet season when
rises above criticality (weak vertical mixing) where it remains through the end of regime III. The Simpson number is in a narrow range around 0.2, indicating that the horizontal salinity gradient is always a driver of the exchange circulation. The
, estimated from a parameterization of the Richardson number, decreases by almost an order of magnitude from regimes I to II. It remains low during III, indicating that the persistent stratification is insulating the exchange flow from destruction by tidal mixing during this time period.
Mesoscale variability in the habitat of the Humboldt Current krill, spring 2007
Authors: Riquelme‐Bugueño Ramiro , Correa‐Ramírez Marco , Escribano Rubén , Núñez Sergio , Hormazábal Samuel 
Published: March 2015

AbstractMesoscale eddies are prominent structures in the world's oceans generating a high degree of spatial and temporal heterogeneity that influences zooplankton distribution. Euphausiids (krill) are a key zooplankton group mainly inhabiting coastal upwelling areas where high productivity, advection, and eddy kinetic energy (EKE) play pivotal roles in the distribution and structure of zooplankton. We analyzed the spatial distribution of the Humboldt Current krill, Euphausia mucronata, in relation to environmental variability and mesoscale circulation during the 2007 austral spring. Using net‐based zooplankton samples, remotely sensed environmental conditions, multivariate analysis, and generalized additive models, we described and tested the effect of oceanographic variability and mesoscale eddies on E. mucronata abundance and biomass. E. mucronata was significantly more abundant in coastal (97%) than oceanic habitats, and more abundant in cyclonic cores (mean: 76 indiv. m−2) than in surrounding waters (mean: 13–29 indiv. m−2). Abundance correlated to current and EKE fields at >10–20 cm s−1 and >50–200 cm2 s−2, respectively, and biomass correlated negatively to sea level anomaly and positively to alongshore winds. Krill abundance and biomass were also strongly coupled to both eddy dynamics and the coastal upwelling regime in spring 2007. Mesoscale eddies may doubly influence the E. mucronata population dynamic by retaining krill within them and, by advection from coastal to oligotrophic regions.
The initiation of lightning in thunderclouds: The possible influence of metastable nitrogen and oxygen molecules in initiating lightning streamers
Authors: Lowke J. J. 
Published: March 2015

AbstractAn examination is made of the possible role of metastable molecules of oxygen and nitrogen to contribute to the difference between the observed breakdown field in air of ~25 kV/cm and the electric fields observed in thunderclouds which generally have a maximum of ~3 kV/cm, which suggest much lower breakdown fields. Analysis of steady state equations for electron, ion, and metastable densities indicates that reductions on the order of a factor of 5 are possible in the electric field necessary to sustain a steady state discharge because of (1) electron detachment from negative ions by the oxygen metastable molecules and (2) increased ionization through deexcitation collisions of electrons with metastable nitrogen vibrational states, assuming high vibrational temperatures of the order of the electron temperature. However, solution of the time‐dependent equations for the particle densities indicates that for a uniform discharge, times on the order of 0.1 s are required for the production of sufficient densities of the metastable particles from initial electron densities of ~1011 cm−3. In such times, electron diffusion would have dispersed electrons from any initial narrow electron pulse postulated to be produced by cosmic rays. It is concluded that the role of the metastable molecules, particularly the nitrogen vibrational states, is unlikely to be significant in the initiation of lightning streamers.
Large charge moment change lightning on 31 May to 1 June 2013, including the El Reno tornadic storm
Authors: Lang Timothy J. , Cummer Steven A. , Petersen Danyal , Flores‐Rivera Lizxandra , Lyons Walter A. , MacGorman Donald , Beasley William 
Published: March 2015

AbstractOn 31 May 2013, a line of severe tornadic thunderstorms (the El Reno event) developed during the local afternoon in central Oklahoma, USA. Within range of the Oklahoma Lightning Mapping Array, the evolution of the event can be separated into three distinct periods: an Early period (before 02:00 UTC on 1 June) when the storm consisted of discrete supercells, a Middle period (02:00–05:00 UTC) when the convection began merging into a linear feature and stratiform precipitation developed, and a Late period (after 05:00 UTC) featuring a mature mesoscale convective system (MCS). Each of these periods demonstrated distinct patterns in the large (>100 C km) charge moment change (CMC) lightning that was produced. During the Early period, large‐CMC positive cloud‐to‐ground (+CG) lightning was produced in the convective cores of supercells. These flashes were small in area (typically <500 km2) and were commonly associated with a sloping midlevel positive charge region in the echo overhang on the storm's forward flank. The Middle period featured a population of larger +CMCs (>500 km2, >300 C km) in the developing stratiform, similar to typical sprite‐parent lightning in MCSs. During the Late period, convective large CMC +CGs ceased and instead large‐CMC negative CGs were produced in and near the MCS convection. These flashes neutralized charge both in convection as well as in adjacent stratiform and anvil precipitation. The results suggest that the CMC metric has potential applications for studying tropospheric weather.
Cloud supersaturations from CCN spectra Hoppel minima
Authors: Hudson James G. , Noble Stephen , Tabor Samantha 
Published: March 2015

AbstractHigh‐resolution cloud condensation nucleus (CCN) spectral measurements in two aircraft field projects, Marine Stratus/Stratocumulus Experiment (MASE) and Ice in Clouds Experiment‐Tropical (ICE‐T), often showed bimodality that had previously been observed in submicrometer aerosol size distributions obtained by differential mobility analyzers. However, a great deal of spectral shape variability from very bimodal to very monomodal was observed in close proximity. Cloud supersaturation (S) estimates based on critical S, Sc, at minimal CCN concentrations between two modes (Hoppel minima) were ascertained for 63% of 325 measured spectra. These cloud S were lower than effective S (Seff) determined by comparing ambient CCN spectra with nearby cloud droplet concentrations (Nc). Averages for the polluted MASE stratus were 0.15 and 0.23% and for the cumulus clouds of ICE‐T 0.44 and 1.03%. This cloud S disagreement between the two methods might in part be due to the fact that Hoppel minima include the effects of cloud processing, which push CCN spectra toward lower S. Furthermore, there is less cloud processing by the smaller cloud droplets, which might be related to smaller droplets evaporating more readily. Significantly lower concentrations within the more bimodal spectra compared with the monomodal spectra indicated active physical processes: Brownian capture of interstitial CCN and droplet coalescence. Chemical cloud processing also contributed to bimodality, especially in MASE.
Diurnal patterns in lightning activity over South America
Authors: Ávila Eldo E. , Bürgesser Rodrigo E. , Castellano Nesvit E. , Nicora M. Gabriela 
Published: March 2015

AbstractSatellite observations of lightning flash distribution data are used to examine the diurnal cycle of lightning activity over the tropical and subtropical regions of South America. A harmonic analysis is used to study the spatial variations in the peak and strength of diurnal lightning activity across this area. Results show that in the northern and central regions of South America, the times of maxima in lightning activity was concentrated from late afternoon to evening hours (between 14:00 and 18:00 local time), which may be associated with the peaking of the local convective activity connected with heating of the surface caused by daytime insolation. In subtropical South America, particularly in the area limited by 25°S, 35°S of latitude and 70°W, 50°W of longitude, the time of maximum lightning activity was shifted to nocturnal hours, extending from close to midnight to early morning hours. This behavior can be associated to the peak in mesoscale convective systems in the region which occurs in the morning hours. The annual flash densities in the tropical and subtropical parts of the continent were found to have comparable magnitudes. However, the contribution of the continental tropics to the global electric circuit dominates over the continental subtropics contribution throughout all seasons, since the surface covered by the tropical region is more than twice the area covered by the subtropical region.
Evidence for different episodes of aeolian construction and a new type of wind streak in the 2016 ExoMars landing ellipse in Meridiani Planum, Mars
Authors: Silvestro S. , Vaz D. A. , Di Achille G. , Popa I. C. , Esposito F. 
Published: March 2015

AbstractWe present evidence for a complex, multigenerational bed form pattern and a new type of wind streak (the ripple streak) in the landing site ellipse of the 2016 ExoMars Entry descent and landing Demonstrator Module (EDM) in Meridiani Planum (Mars). We identified three main groups of bright‐toned bed forms. Population 3, represented by NE‐SW trending bed forms located inside craters, was emplaced by winds coming from the NW or the SE. Population 2, emplaced by strong easterlies, formed by intracrater transverse aeolian ridges (TARs) and N‐S trending megaripples (plains ripples). Population 1 consists of a relict bed form pattern emplaced by winds coming from the north or south. Alternatively, population 1 can represent a sand ribbon pattern that formed together with the plain ripples. We also report the presence of a new type of wind streak, the ripple streak, which is formed by the population 2 bed forms clustered in the wake zone of impact craters. Based on the results of this work, we now know the EDM module is set to land in a complex aeolian environment. Data from the Dust Characterization, Risk Assessment, and Environment Analyser on the Martian Surface onboard the EDM can help to better decipher the wind regime in Meridiani Planum.
Planform evolution of two anabranching structures in the Upper Peruvian Amazon River
Authors: Frias C. E. , Abad J. D. , Mendoza A. , Paredes J. , Ortals C. , Montoro H. 
Published: March 2015

AbstractWe present a study to relate the sinuosity of the main channel and its effect on the dynamics of the secondary channels of anabranching structures. For this purpose, two locations of the Peruvian Amazon River were selected: (1) a site with a medium to high‐sinuosity main channel (MS site: Muyuy, Peru) and (2) a site with a low‐sinuosity main channel (LS site: at the triple boundary between Brazil, Colombia, and Peru). The main channels for both the MS and LS anabranching structures have freedom to migrate in the lateral direction, while at least one of their secondary channels is adjacent to the geological valley. For MS and LS sites, temporal analysis of planform evolution was carried out using 30 years of satellite imagery from which metrics such as width, sinuosity, and annual maximum migration rates of main and secondary channels were calculated. Additionally, detailed hydrodynamic and bed morphology field measurements were carried out, and a two‐dimensional shallow water numerical model was developed. For a medium to high‐sinuosity main channel anabranching structure, the secondary channels present a dominant mechanism for reworking the floodplain, while for the low‐sinuosity anabranching structure, the main channel planform dynamics is dominant. Flow velocities along the main and secondary channels for low, transition, and high‐flow discharges describe that for MS (LS) site, the velocities are much higher along the secondary (main) channels.
Spatial and temporal characteristics of rainfall in Africa: Summary statistics for temporal downscaling
Authors: Kaptué Armel T. , Hanan Niall P. , Prihodko Lara , Ramirez Jorge A. 
Published: March 2015

AbstractAn understanding of rainfall characteristics at multiple spatiotemporal scales is of great importance for hydrological, biogeochemical, and land surface modeling studies. In the present study, patterns of rainfall are analyzed over the African continent based on 3 hourly 0.25° Tropical Rainfall Measuring Mission (TRMM) estimates between 1998 and 2012 to produce monthly statistical summaries. The selected rain event properties are multiyear means of precipitation total amount (mm), event frequency (number), rate (mm/h), and duration (h) calculated independently for each calendar month. Analysis of 3 hourly and daily events in the 1998–2012 period suggests that rainfall amount can be summarized using gamma probability density functions. Assuming stationarity, gamma probability density functions of the total depth of 3 hourly and daily events are estimated and then used for temporal downscaling of monthly rainfall estimates (past or future). As a result, we generate 3 hourly and daily rainfall estimates that are pixelwise statistically indistinguishable from the observations while preserving monthly totals. Example scripts are provided that can be used to access monthly statistics and implement downscaling using archival (or projected) monthly rainfall estimates. These statistics could also be utilized for the assessment of rainfall from atmospheric models.
Natural gas price uncertainty and the cost‐effectiveness of hedging against low hydropower revenues caused by drought
Authors: Kern Jordan D. , Characklis Gregory W. , Foster Benjamin T. 
Published: March 2015

AbstractProlonged periods of low reservoir inflows (droughts) significantly reduce a hydropower producer's ability to generate both electricity and revenues. Given the capital intensive nature of the electric power industry, this can impact hydropower producers’ ability to pay down outstanding debt, leading to credit rating downgrades, higher interests rates on new debt, and ultimately, greater infrastructure costs. One potential tool for reducing the financial exposure of hydropower producers to drought is hydrologic index insurance, in particular, contracts structured to payout when streamflows drop below a specified level. An ongoing challenge in developing this type of insurance, however, is minimizing contracts’ “basis risk,” that is, the degree to which contract payouts deviate in timing and/or amount from actual damages experienced by policyholders. In this paper, we show that consideration of year‐to‐year changes in the value of hydropower (i.e., the cost of replacing it with an alternative energy source during droughts) is critical to reducing contract basis risk. In particular, we find that volatility in the price of natural gas, a key driver of peak electricity prices, can significantly degrade the performance of index insurance unless contracts are designed to explicitly consider natural gas prices when determining payouts. Results show that a combined index whose value is derived from both seasonal streamflows and the spot price of natural gas yields contracts that exhibit both lower basis risk and greater effectiveness in terms of reducing financial exposure.