bluuebunny/crossref_metadata_2025 huggingface dataset:
Rhetorical legacies of leadership: projections of ‘benevolent leadership’ in pre- and post-genocide Rwanda
Authors: Desrosiers Marie-Eve , Thomson Susan
Published: August 2011

Comparing pre- and post-genocide Rwanda, this article argues that clear continuities exist between the regimes of Juvénal Habyarimana and Paul Kagame. Both have projected a remarkably similar image of ‘benevolent leadership’. Presenting themselves as harbingers of an ‘improved’ or ‘new’ Rwanda, both leaderships have claimed to be best able and willing to guide Rwanda along the right path to peace, security, ethnic unity and development. ‘Benevolent leadership’ in both periods has also served as a tool to try and shape regime relationships with international and domestic audiences. Internationally, each government has worked to promote Rwanda and its authorities as a good development partner. Domestically, these projections have served to establish norms of order and obedience. We argue that projections of ‘benevolent leadership’ have been a tool designed to win over the international community and discipline the Rwandan population.
The lifetime impact of attention deficit hyperactivity disorder: results from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC)
Authors: Bernardi S. , Faraone S. V. , Cortese S. , Kerridge B. T. , Pallanti S. , Wang S. , Blanco C.
Published: August 2011

Background

The aim of the study was to present nationally representative data on the lifetime independent association between attention deficit hyperactivity disorder (ADHD) and psychiatric co-morbidity, correlates, quality of life and treatment seeking in the USA.

Method

Data were derived from a large national sample of the US population. Face-to-face surveys of more than 34 000 adults aged 18 years and older residing in households were conducted during the 2004–2005 period. Diagnoses of ADHD, Axis I and II disorders were based on the Alcohol Use Disorder and Associated Disabilities Interview Schedule-DSM-IV version.

Results

ADHD was associated independently of the effects of other psychiatric co-morbidity with increased risk of bipolar disorder, generalized anxiety disorder, post-traumatic stress disorder, specific phobia, and narcissistic, histrionic, borderline, antisocial and schizotypal personality disorders. A lifetime history of ADHD was also associated with increased risk of engaging in behaviors reflecting lack of planning and deficient inhibitory control, with high rates of adverse events, lower perceived health, social support and higher perceived stress. Fewer than half of individuals with ADHD had ever sought treatment, and about one-quarter had ever received medication. The average age of first treatment contact was 18.40 years.

Conclusions

ADHD is common and associated with a broad range of psychiatric disorders, impulsive behaviors, greater number of traumas, lower quality of life, perceived social support and social functioning, even after adjusting for additional co-morbidity. When treatment is sought, it is often in late adolescence or early adulthood, suggesting the need to improve diagnosis and treatment of ADHD.
Origin and deposition sites influence seed germination and seedling survival of Manilkara zapota: implications for long-distance, animal-mediated seed dispersal
Authors: O'Farrill Georgina , Chapman Colin A. , Gonzalez Andrew
Published: August 2011

The distribution and dynamics of plant populations depend on the recruitment of young individuals, which is influenced by seed production, animal seed dispersal, dispersal distance, and the deposition of seeds in favourable places for seed germination/establishment and seedling survival. In particular, seeds dispersed over long distances will likely encounter new environmental conditions that occur at large spatial scales, with seed and seedling survival influenced by the adaptation of plant populations to soil and climate conditions. In this paper, it is hypothesized that seed germination and seedling survival probabilities depend on seed origin and deposition sites. A reciprocal seed and seedling transplant experiment was carried out with zapote seeds (Manilkara zapota) to determine the effect of origin and deposition sites on seed germination and seedling survival over a year in the Greater Calakmul Region of Mexico. Two origin and two deposition sites were selected that show different soil moisture levels within the habitat of the Baird's tapir, a major seed disperser of M. zapota seeds. The results show that sites of origin and deposition influenced seed germination and seedling survival probabilities. This suggests that the displacement of seeds far from parent trees, while potentially reducing intraspecific competition, does not ensure their survival, and that seeds need to be deposited in microsites within their environmental tolerance for dispersal to be successful. Furthermore, this paper emphasizes the importance of field experiments to provide strong inference about the effects of environmental conditions on recruitment and distribution of plant species.
Carbon-related border tax adjustment: mitigating climate change or restricting international trade?
Authors: KAUFMANN CHRISTINE , WEBER ROLF H.
Published: August 2011

Border tax adjustments in the form of carbon taxes on products from countries with lax environmental production standards or in the form of a required participation in an emissions allowances' trading system have become a heavily debated issue under WTO law. Such an adjustment might be permissible if energy taxes as indirect taxes are applied on inputs during the production process. Compliance with the Most Favoured Nation principle has less practical importance than the not-yet settled likeness discussion under the National Treatment principle. Consequently, since the compatibility of carbon-related border tax adjustment measures is partly contested, potential justifications such as the conservation of exhaustible national resources or the protection of health (Art. XX GATT) become relevant. The application of the necessity and proportionality test requires that carbon measures are tailored so as to substantially contribute to the achievement of environmental objectives and do not create any arbitrary or unjustified discrimination.
Exploring the Impact of the Japanese Long-Term Care Insurance Act on the Gendered Stratification of the Care Labour Market Through an Analysis of the Domiciliary Care Provided by Welfare Non-Profit Organisations
Authors: Yamashita Junko
Published: August 2011

Japan's implementation of the Long Term Care Insurance Act in 2000 provides a good example with which to examine the restructuring process of care services for older people, as these have come to be commodified by the welfare state. By focusing on Welfare Non-Profit Organisations provision, this article explores the significance of gender in the restructuring process. It reveals that care services are stratified with institutional care placed at the top of hierarchy of care services costs, and domestic task services at the bottom. There is an unequal distribution of gender and organisational type for each type of care work.
Probability-Based and Measurement-Related Hypotheses With Full Restriction for Investigations by Means of Confirmatory Factor Analysis
Authors: Schweizer Karl
Published: August 2011

Probability-based and measurement-related hypotheses for confirmatory factor analysis of repeated-measures data are investigated. Such hypotheses comprise precise assumptions concerning the relationships among the true components associated with the levels of the design or the items of the measure. Measurement-related hypotheses concentrate on the assumed processes, as, for example, transformation and memory processes, and represent treatment-dependent differences in processing. In contrast, probability-based hypotheses provide the opportunity to consider probabilities as outcome predictions that summarize the effects of various influences. The prediction of performance guided by inexact cues serves as an example. In the empirical part of this paper probability-based and measurement-related hypotheses are applied to working-memory data. Latent variables according to both hypotheses contribute to a good model fit. The best model fit is achieved for the model including latent variables that represented serial cognitive processing and performance according to inexact cues in combination with a latent variable for subsidiary processes.
Variance Heterogeneity in Published Psychological Research
Authors: Ruscio John , Roche Brendan
Published: August 2011

Parametric assumptions for statistical tests include normality and equal variances. Micceri (1989) found that data frequently violate the normality assumption; variances have received less attention. We recorded within-group variances of dependent variables for 455 studies published in leading psychology journals. Sample variances differed, often substantially, suggesting frequent violation of the assumption of equal population variances. Parallel analyses of equal-variance artificial data otherwise matched to the characteristics of the empirical data show that unequal sample variances in the empirical data exceed expectations from normal sampling error and can adversely affect Type I error rates of parametric statistical tests. Variance heterogeneity was unrelated to relative group sizes or total sample size and observed across subdisciplines of psychology in experimental and correlational research. These results underscore the value of examining variances and, when appropriate, using data-analytic methods robust to unequal variances. We provide a standardized index for examining and reporting variance heterogeneity.
Estimation of and Confidence Interval Formation for Reliability Coefficients of Homogeneous Measurement Instruments
Authors: Kelley Ken , Cheng Ying
Published: August 2011

The reliability of a composite score is a fundamental and important topic in the social and behavioral sciences. The most commonly used reliability estimate of a composite score is coefficient α. However, under regularity conditions, the population value of coefficient α is only a lower bound on the population reliability, unless the items are essentially τ-equivalent, an assumption that is likely violated in most applications. A generalization of coefficient α, termed ω, is discussed and generally recommended. Furthermore, a point estimate itself almost certainly differs from the population value. Therefore, it is important to provide confidence interval limits so as not to overinterpret the point estimate. Analytic and bootstrap methods are described in detail for confidence interval construction for ω. We go on to recommend the bias-corrected bootstrap approach for ω and provide open source and freely available R functions via the MBESS package to implement the methods discussed.
Subjective p Intervals
Authors: Lai Jerry , Fidler Fiona , Cumming Geoff
Published: August 2011

Suppose you obtain p = .02 in an experiment, then replicate the experiment with new samples. What p value might you obtain, and what interval has an 80% chance of including that replication p? Under conservative assumptions the answer is, perhaps surprisingly (.0003, .30). The authors report three email surveys that asked authors of articles published in leading journals in psychology, medicine, or statistics to estimate such intervals. Overall response rate (7%) was low, but responses from 360 researchers gave intervals with an average 40% to 50% chance of including replication p, rather than the target 80%. Results were similar for all three disciplines. Respondents generally found the task unfamiliar and difficult. There was great variability over respondents, but almost all of them gave intervals that were too short. This widespread, and often severe, underestimation of the variability of p may help to explain why researchers place too much interpretive weight on single p values.
X‐ray fluorescence core scanning records of chemical weathering and monsoon evolution over the past 5 Myr in the southern South China Sea
Authors: Tian Jun , Xie Xin , Ma Wentao , Jin Haiyan , Wang Pinxian
Published: August 2011

We present ultrahigh resolution K/Al and Ti/Al records at ODP Site 1143 for the past 5 Myr, which were obtained by nondestructive X‐ray fluorescence (XRF) core scanning on the sediment surface of the archive half cores of this site at a step of 1 cm. The K/Al and Ti/Al records and their amplitudes of the variability on glacial/interglacial cycles show a markedly increasing trend since ∼2.5 Ma, indicating a gradual strengthening of the chemical weathering and the East Asian summer monsoon under the influences from the Northern Hemisphere glaciation (NHG). Evolutive cross spectral analyses of K/Al with benthic foraminiferal δ18O reveal that phases of the East Asian summer monsoon abruptly changed by more than 90° at 4.0 Ma, 2.75 Ma, 1.0 Ma and 0.6 Ma relative to global ice volume at the obliquity and the precession bands over the past 5 Myr. Strong 400 kyr and 100 kyr cycles in the K/Al and Ti/Al records consistently exist over the past 5 Myr. Particularly, these cycles are highly coherent with the long and short eccentricity cycles in the truncated insolation at 65°N, indicating an eccentricity forcing of the East Asian summer monsoon. The chemical weathering recorded in the elemental records of ODP Site 1143 also shows highly coherent relationship with the ocean carbon reservoir at the eccentricity, the obliquity and the precession bands over the late Pliocene and Pleistocene.
A model‐data comparison of δ13C in the glacial Atlantic Ocean
Authors: Hesse T. , Butzin M. , Bickert T. , Lohmann G.
Published: August 2011

We compare a compilation of 220 sediment core δ13C data from the glacial Atlantic Ocean with three‐dimensional ocean circulation simulations including a marine carbon cycle model. The carbon cycle model employs circulation fields which were derived from previous climate simulations. All sediment data have been thoroughly quality controlled, focusing on epibenthic foraminiferal species (such as Cibicidoides wuellerstorfi or Planulina ariminensis) to improve the comparability of model and sediment core carbon isotopes. The model captures the general δ13C pattern indicated by present‐day water column data and Late Holocene sediment cores but underestimates intermediate and deep water values in the South Atlantic. The best agreement with glacial reconstructions is obtained for a model scenario with an altered freshwater balance in the Southern Ocean that mimics enhanced northward sea ice export and melting away from the zone of sea ice production. This results in a shoaled and weakened North Atlantic Deep Water flow and intensified Antarctic Bottom Water export, hence confirming previous reconstructions from paleoproxy records. Moreover, the modeled abyssal ocean is very cold and very saline, which is in line with other proxy data evidence.
A medium‐scale traveling ionospheric disturbance observed from the ground and from space
Authors: Dymond K. F. , Watts C. , Coker C. , Budzien S. A. , Bernhardt P. A. , Kassim N. , Lazio T. J. , Weiler K. , Crane P. C. , Ray P. S. , Cohen A. , Clarke T. , Rickard L. J. , Taylor G. B. , Schinzel F. , Pihlstrom Y. , Kuniyoshi M. , Close S. , Colestock P. , Myers S. , Datta A.
Published: August 2011

We report ultraviolet optical observations from space of a Medium‐Scale Traveling Ionospheric Disturbance (MSTID) made during the Combined Radio Interferometry and COSMIC Experiment in Tomography Campaign (CRICKET) held on September 15, 2007 at ∼8:30 UT. The experiment used a Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC also known as FORMOSAT‐3) satellite in conjunction with the Very Large Array (VLA) radio telescope, located near Socorro, NM, to study the ionosphere from the global scale down to the regional scale while the TIDs propagated through it. The COSMIC/FORMOSAT‐3 satellite measured the F region electron density both horizontally and with altitude while the VLA measured the directions and speeds of the TIDs. These observations provide new information on this poorly understood class of TID and demonstrate the possibility of studying MSTIDs using space‐based optical instruments.
Different homogenization methods based on scattering parameters of dielectric‐composite slabs
Authors: Qi Jiaran , Kettunen Henrik , Wallén Henrik , Sihvola Ari
Published: August 2011

The dispersion of the effective permittivity of a dielectric‐composite slab is analyzed in a quasi‐dynamic range using the simulated transmission and reflection data from the slab illuminated by an obliquely incident plane wave. Based on the retrieval results, the procedure for finding the dynamic trust region of the quasi‐static Lord Rayleigh estimate for the effective permittivities of such composites is then developed. According to this process, the upper frequency limit of this trust region is numerically determined by an interpolation function. The proposed function of the inclusion area fraction p and relative permittivity ɛi is demonstrated as a good predictor within the ranges 0.1 ≤ p ≤ 0.5 and 10 ≤ ɛi ≤ 60. It is further shown that within the above ranges the effective wavelength inside the material should be at least 33 times the edge length of the unit cell, in order to ensure that the defined relative difference between the retrieved effective permittivity and the quasi‐static estimate is not larger than 1%.
Data ingestion into NeQuick 2
Authors: Nava B. , Radicella S. M. , Azpilicueta F.
Published: August 2011

NeQuick 2 is the latest version of the NeQuick ionosphere electron density model developed at the Aeronomy and Radiopropagation Laboratory of the Abdus Salam International Centre for Theoretical Physics (ICTP) ‐ Trieste, Italy with the collaboration of the Institute for Geophysics, Astrophysics and Meteorology of the University of Graz, Austria. It is a quick‐run model particularly designed for trans‐ionospheric propagation applications that has been conceived to reproduce the median behavior of the ionosphere. To provide 3‐D specification of the ionosphere electron density for current conditions, different ionosphere electron density retrieval techniques based on the NeQuick adaptation to GPS‐derived Total Electron Content (TEC) data and ionosonde measured peak parameters values have been developed. In the present paper the technique based on the ingestion of global vertical TEC map into NeQuick 2 will be validated and an assessment of the capability of the model to reproduce the ionosphere day‐to‐day variability will also be performed. For this purpose hourly GPS‐derived global vertical TEC maps and hourly foF2 values from about 20 ionosondes corresponding to one month in high solar activity and one month in low solar activity period will be used. Furthermore, the first results concerning the ingestion of space‐based GPS‐derived TEC data will be presented.
Late Neogene and active orogenic uplift in the Central Pontides associated with the North Anatolian Fault: Implications for the northern margin of the Central Anatolian Plateau, Turkey
Authors: Yildirim Cengiz , Schildgen Taylor F. , Echtler Helmut , Melnick Daniel , Strecker Manfred R.
Published: August 2011

Surface uplift at the northern margin of the Central Anatolian Plateau (CAP) is integrally tied to the evolution of the Central Pontides (CP), between the North Anatolian Fault (NAF) and the Black Sea. Our regional morphometric and plate kinematic analyses reveal topographic anomalies, steep channel gradients, and local high relief areas as indicators of ongoing differential surface uplift, which is higher in the western CP compared to the eastern CP and fault‐normal components of geodetic slip vectors and the character of tectonic activity of the NAF suggest that stress is accumulated in its broad restraining bend. Seismic reflection and structural field data show evidence for a deep structural detachment horizon responsible for the formation of an actively northward growing orogenic wedge with a positive flower‐structure geometry across the CP and the NAF. Taken together, the tectonic, plate kinematic, and geomorphic observations imply that the NAF is the main driving mechanism for wedge tectonics and uplift in the CP. In addition, the NAF Zone defines the boundary between the extensional CAP and the contractional CP. The syntectonic deposits within inverted intermontane basins and deeply incised gorges suggest that the formation of relief, changes in sedimentary dynamics, and >1 km fluvial incision resulted from accelerated uplift starting in the early Pliocene. The Central Pontides thus provide an example of an accretionary wedge with surface‐breaking faults that play a critical role in mountain building processes, sedimentary basin development, and ensuing lateral growth of a continental plateau since the end of the Miocene.
Oligo‐Miocene extensional tectonics and fluid flow across the Northern Snake Range detachment system, Nevada
Authors: Gébelin Aude , Mulch Andreas , Teyssier Christian , Heizler Matt , Vennemann Torsten , Seaton Nicholas C. A.
Published: August 2011

The Northern Snake Range (Nevada) represents a spectacular example of a metamorphic core complex and exposes a complete section from the mylonitic footwall into the hanging wall of a fossil detachment system. Paired geochronological and stable isotopic data of mylonitic quartzite within the detachment footwall reveal that ductile deformation and infiltration of meteoric fluids occurred between 27 and 23 Ma. 40Ar/39Ar ages display complex recrystallization‐cooling relationships but decrease systematically from 26.9 ± 0.2 Ma at the top to 21.3 ± 0.2 Ma at the bottom of footwall mylonite. Hydrogen isotope (δD) values in white mica are very low (−150 to −145 ‰) within the top 80–90 m of detachment footwall, in contrast to values obtained from the deeper part of the section where values range from −77 to −64 ‰, suggesting that time‐integrated interaction between rock and meteoric fluid was restricted to the uppermost part of the mylonitic footwall. Pervasive mica‐water hydrogen isotope exchange is difficult to reconcile with models of 40Ar loss during mylonitization solely by volume diffusion. Rather, we interpret the 40Ar/39Ar ages of white mica with low‐δD values to date syn‐mylonitic hydrogen and argon isotope exchange, and we conclude that the hydrothermal system of the Northern Snake Range was active during late Oligocene (27–23 Ma) and has been exhumed by the combined effects of ductile strain, extensional detachment faulting, and erosion.
Along‐strike variability of back‐arc basin collapse and the initiation of sedimentation in the Magallanes foreland basin, southernmost Andes (53–54.5°S)
Authors: McAtamney Janelle , Klepeis Keith , Mehrtens Charlotte , Thomson Stuart , Betka Paul , Rojas Lisandro , Snyder Shane
Published: August 2011

The Patagonian Andes record the Cretaceous demise of the quasi‐oceanic Rocas Verdes back‐arc basin and formation of the Magallanes foreland basin. For >500 km along the strike of the mountains, this tectonic transition is marked by a sandstone‐mudstone package that records the beginning of turbiditic sand deposition and fan growth. Sandstone modal analyses and U‐Pb detrital zircon spectra show changes in rock composition and provenance across the transition on a basin‐wide scale, indicating it has tectonic significance and is related to orogenic uplift and the progressive evolution of the Andean fold‐thrust belt. Spatial variations in transition zone characteristics indicate the foreland basin's central and southern sectors were fed by different sources and probably record separate fans. At Bahía Brookes, on Tierra del Fuego, foreland basin sedimentation began at least after 88–89 Ma, and possibly after ∼85 Ma, several million years after it did ∼700 km away at the northern end of the basin. This event coincided with increased arc volcanism and the partial obduction of the basaltic Rocas Verdes basin floor onto continental crust. By 81–80 Ma, conglomerate deposition and increased compositional and provenance complexity, including the abundance of metamorphic lithic fragments, indicate that the obducted basaltic floor first became emergent and was eroding. The results suggest that the beginning of turbidite sedimentation in the Magallanes foreland basin and the progressive incorporation and exhumation of deeply buried rocks in the Andean fold‐thrust belt, occurred later in southern Patagonia than in the north by a few million years.
Predicting foraging wading bird populations in Everglades National Park from seasonal hydrologic statistics under different management scenarios
Authors: Kwon Hyun‐Han , Lall Upmanu , Engel Vic
Published: August 2011

The ability to map relationships between ecological outcomes and hydrologic conditions in the Everglades National Park (ENP) is a key building block for their restoration program, a primary goal of which is to improve conditions for wading birds. This paper presents a model linking wading bird foraging numbers to hydrologic conditions in the ENP. Seasonal hydrologic statistics derived from a single water level recorder are well correlated with water depths throughout most areas of the ENP, and are effective as predictors of wading bird numbers when using a nonlinear hierarchical Bayesian model to estimate the conditional distribution of bird populations. Model parameters are estimated using a Markov chain Monte Carlo (MCMC) procedure. Parameter and model uncertainty is assessed as a byproduct of the estimation process. Water depths at the beginning of the nesting season, the average dry season water level, and the numbers of reversals from the dry season recession are identified as significant predictors, consistent with the hydrologic conditions considered important in the production and concentration of prey organisms in this system. Long‐term hydrologic records at the index location allow for a retrospective analysis (1952–2006) of foraging bird numbers showing low frequency oscillations in response to decadal fluctuations in hydroclimatic conditions. Simulations of water levels at the index location used in the Bayesian model under alternative water management scenarios allow the posterior probability distributions of the number of foraging birds to be compared, thus providing a mechanism for linking management schemes to seasonal rainfall forecasts.
Stochastic modeling of salt accumulation in the root zone due to capillary flux from brackish groundwater
Authors: Shah S. H. H. , Vervoort R. W. , Suweis S. , Guswa A. J. , Rinaldo A. , van der Zee S. E. A. T. M.
Published: August 2011

Groundwater can be a source of both water and salts in semiarid areas, and therefore, capillary pressure–induced upward water flow may cause root zone salinization. To identify which conditions result in hazardous salt concentrations in the root zone, we combined the mass balance equations for salt and water, further assuming a Poisson‐distributed daily rainfall and brackish groundwater quality. For the water fluxes (leaching, capillary upflow, and evapotranspiration), we account for osmotic effects of the dissolved salt mass using Van‘t Hoff's law. Root zone salinity depends on salt transport via capillary flux and on evapotranspiration, which concentrates salt in the root zone. Both a wet climate and shallow groundwater lead to wetter root zone conditions, which in combination with periodic rainfall enhances salt removal by leaching. For wet climates, root zone salinity (concentrations) increases as groundwater is more shallow (larger groundwater influence). For dry climates, salinity increases as groundwater is deeper because of a drier root zone and less leaching. For intermediate climates, opposing effects can push the salt balance either way. Root zone salinity increases almost linearly with groundwater salinity. With a simple analytical approximation, maximum concentrations can be related to the mean capillary flow rate, leaching rate, water saturation, and groundwater salinity for different soils, climates, and groundwater depths.
The role of tropical modes of variability in recent rainfall deficits across the Murray‐Darling Basin
Authors: Timbal B. , Hendon H.
Published: August 2011

Southeastern Australia has been experiencing ongoing rainfall deficits since 1997. The spatial extent of the current drought closely corresponds to those regions where rainfall is influenced by interannual variations in the intensity of the subtropical ridge. An upward trend in the intensity of the subtropical ridge thus provides an explanation for the recent rainfall deficit. The possibility that slow variations in tropical modes of variability that are known to influence rainfall in the region, such as the El Niño–Southern Oscillation, may have contributed to southeastern Australia rainfall deficits is investigated using a tripole sea surface temperature index. This index takes into account key influences on Australian climate from variations in both the Indian and Pacific Oceans. The tripole index correlates well with rainfall variations across southeastern Australia on interannual to decadal time scales in winter and spring but not in autumn when most of the recent rainfall deficits have occurred. The influence of tropical sea surface temperature (SST) variations associated with the tripole on southeastern Australian rainfall is explained in terms of Rossby wave propagation, which helps us to understand why the impact is stronger in the southern half of the Murray‐Darling Basin and why there is no relationship in autumn. On the basis of the linear relationship between the tripole SST variation and rainfall across the Murray‐Darling Basin, we conclude that tropical SSTs have not contributed to the observed rainfall deficiencies in southeast Australia since 1997 but did contribute to the 1935–1945 rainfall deficits.
Riparian soil temperature modification of the relationship between flow and dissolved organic carbon concentration in a boreal stream
Authors: Winterdahl Mattias , Futter Martyn , Köhler Stephan , Laudon Hjalmar , Seibert Jan , Bishop Kevin
Published: August 2011

Discharge is often strongly correlated to the temporal variability of dissolved organic carbon concentrations ([DOC]) in watercourses. One recently proposed way to model this is the riparian flow‐concentration integration model (RIM) concept that accounts for the role of flow pathway control on [DOC] dynamics in streams. However, in boreal systems, there is also commonly a seasonal pattern, which cannot be explained by variability in discharge alone. The objectives with this study were to (1) demonstrate RIM as a tool for studying variability in stream water chemistry, (2) investigate factors related to stream water DOC variability, and (3) modify RIM to account for these factors. RIM was used with 14 years of daily discharge and almost 500 stream measurements of [DOC] from a forested boreal headwater stream. We used the calibrated RIM to account for discharge influences and then investigated variables that could be related to DOC variability (air and soil temperature, soil moisture, precipitation, antecedent flow and stream sulfate). Five alternative formulations of RIM, with temporally varying soil concentration profiles based on the variability in soil temperature and/or antecedent flow, were evaluated. The model where only the effects of riparian soil temperature on dynamics in DOC depth profiles were included performed best overall. This dynamic RIM improved the Nash‐Sutcliffe to 0.58 compared to 0.42 for the flow‐only formulation and reduced the median absolute error from 3.0 to 2.1 mg L−1. This study demonstrates that RIM is a simple way of modeling stream DOC and exploring controls on stream water chemistry.
Incoherent scatter radar study of the terdiurnal tide in the E‐ and F‐region heights at Arecibo
Authors: Gong Yun , Zhou Qihou
Published: August 2011

We report the analysis of the terdiurnal tide in the meridional wind from 90 to 350 km at a low latitude station. Our data is based on nine days of consecutive observation made by the Arecibo incoherent scatter radar during January 14–23, 2010. The terdiurnal tide is observed to be prominent at E‐region heights in the first four days (Jan. 14–18) and at the F‐region heights in the last five days (Jan. 18–23). The terdiurnal tide is among the two strongest tidal components in both regions. The vertical wavelength of the terdiurnal tide is about 100 km, and 950 km, for the altitude range of 128 to 142 km, and 180 to 320 km, respectively. The F‐region terdiurnal tide amplitude is found to be well correlated with the background meridional wind in the lower F‐region. Our analysis does not reveal any evidence that non‐linear interaction between diurnal and semidiurnal tides is important for the F‐region terdiurnal tide.
A new perspective on gravity waves in the Martian atmosphere: Sources and features
Authors: Miyoshi Y. , Forbes J. M. , Moudden Y.
Published: August 2011

Using a Mars general circulation model (GCM), we investigate the characteristics of gravity waves in the atmosphere of Mars. Fluctuations due to internal gravity waves at tidal periods, such as diurnal, semidiurnal, and terdiurnal tides, are predominant in the lower atmosphere. In particular, the diurnal and semidiurnal tides having large zonal wave numbers (s > 10) are significant. Fluctuations associated with nontidal gravity wave components in the lower atmosphere are negligibly small except for the stationary orographic component. Nontidal gravity waves grow in amplitude in the middle atmosphere, while tidal components remain the dominant form of gravity waves. In the upper atmosphere (>80 km), nontidal gravity wave components and fluctuations due to the diurnal and semidiurnal tides having large zonal wave numbers are equally important. We estimate the global distributions of the gravity wave energy at various altitudes and attempt to define various sources. Our results show that most nontidal gravity wave energy is closely related with the diurnal amplitude except in the lower atmosphere where association with orography predominates. This suggests that nonorographic gravity waves are generated by the breaking and dissipation of the diurnal tide. On the other hand, nontidal gravity wave energy in the lower atmosphere peaks in mountainous regions and points to their source as being of orographic nature. We also enumerate the major differences between gravity waves on Mars and Earth as simulated by global models.
Formation of gypsum and bassanite by cation exchange reactions in the absence of free‐liquid H2O: Implications for Mars
Authors: Wilson Sasha , Bish David L.
Published: August 2011

Smectites and hydrated Mg sulfate minerals have been identified in close association at various locations on the Martian surface. The hydration states of sulfates and smectites are dependent on temperature and relative humidity (RH), and therefore these minerals have the potential to affect cycling and bioavailability of H2O on Mars. We have conducted X‐ray powder diffraction experiments to investigate cycling of H2O within mixtures of Ca‐bearing smectites and hydrated Mg sulfate minerals under conditions of varying RH similar to those that exist at or just beneath the Martian surface. Our experiments show that under conditions of varying RH, cation‐exchange reactions occur between these two potential components of the Martian regolith, producing gypsum [CaSO4·2H2O] and bassanite [CaSO4·∼0.5H2O] in the absence of free‐liquid H2O. Cation‐exchange reactions were accompanied by significant loss of porosity, warping of the sample surface and, in some cases, volume expansion. The formation of Ca sulfate minerals in these experiments provides evidence for the development of thin films of H2O at mineral surfaces and suggests that similar processes may operate at the arid surface of Mars. Humidity‐driven cation‐exchange reactions between smectites and hydrated Mg sulfate minerals may therefore play a role in shaping the present‐day Martian surface and could have provided a transient source of H2O and nutrients (e.g., major and trace elements and possibly organic micro/macronutrients) for putative microorganisms.
Quantitative evaluation of the low Earth orbit satellite based slant total electron content determination
Authors: Yue Xinan , Schreiner William S. , Hunt Douglas C. , Rocken Christian , Kuo Ying‐Hwa
Published: August 2011

With the increased number of low Earth orbit (LEO) satellites equipped with GPS receivers, LEO based GPS observations play a more important role in space weather research because of better global coverage and higher vertical resolution. GPS slant total electron content (TEC) is one of the most important space weather products. In this paper, the LEO based slant TEC derivation method and the main error sources, including the multipath calibration, the leveling of phase to the pseudorange TEC, and the differential code bias (DCB) estimation, are described systematically. It is found that the DCB estimation method based on the spherical symmetry ionosphere assumption can obtain reasonable results by analyzing data from multiple LEO missions. The accuracy of the slant TEC might be enhanced if the temperature dependency of DCB estimation is considered. The calculated slant TEC is validated through comparison with empirical models and analyzing the TEC difference of COSMIC colocated clustered observations during the initial stage. Quantitatively, the accuracy of the LEO slant TEC can be estimated at 1–3 tecu, depending on the mission. Possible use of the LEO GPS data in ionosphere and plasmasphere is discussed.
An agent‐based model of farmer decision‐making and water quality impacts at the watershed scale under markets for carbon allowances and a second‐generation biofuel crop
Authors: Ng Tze Ling , Eheart J. Wayland , Cai Ximing , Braden John B.
Published: August 2011

An agent‐based model of farmers' crop and best management practice (BMP) decisions is developed and linked to a hydrologic‐agronomic model of a watershed, to examine farmer behavior, and the attendant effects on stream nitrate load, under the influence of markets for conventional crops, carbon allowances, and a second‐generation biofuel crop. The agent‐based approach introduces interactions among farmers about new technologies and market opportunities, and includes the updating of forecast expectations and uncertainties using Bayesian inference. The model is applied to a semi‐hypothetical example case of farmers in the Salt Creek Watershed in Central Illinois, and a sensitivity analysis is performed to effect a first‐order assessment of the plausibility of the results. The results show that the most influential factors affecting farmers' decisions are crop prices, production costs, and yields. The results also show that different farmer behavioral profiles can lead to different predictions of farmer decisions. The farmers who are predicted to be more likely to adopt new practices are those who interact more with other farmers, are less risk averse, quick to adjust their expectations, and slow to reduce their forecast confidence. The decisions of farmers have direct water quality consequences, especially those pertaining to the adoption of the second‐generation biofuel crop, which are estimated to lead to reductions in stream nitrate load. The results, though empirically untested, appear plausible and consistent with general farmer behavior. The results demonstrate the usefulness of the coupled agent‐based and hydrologic‐agronomic models for normative research on watershed management on the water‐energy nexus.
Assessing interannual variability of evapotranspiration at the catchment scale using satellite‐based evapotranspiration data sets
Authors: Cheng Lei , Xu Zongxue , Wang Dingbao , Cai Ximing
Published: August 2011

The catchment water‐energy balance at the interannual scale remains a challenge for bridging the important gap in our knowledge of the hydrologic cycle. This study investigates interannual evapotranspiration (ET) variability and water‐energy balance at over 547 catchments across the contiguous United States in different climate zones. The investigation is based on ET data estimated from satellite images and surface daily meteorological data during the period of 1983–2006 provided by the University of Montana. We find that the interannual relationship between annual potential ET to annual precipitation (PET/P) and ET/P, the energy, and water factors defined with the Budyko curve framework can be captured by a linear function, with an average goodness of fit of 0.928 over all the catchments. The linear relationship is validated by another independent remote sensing ET product generated by the University of Washington and is demonstrated to be rational using regression diagnostics. Additionally, a comparison study using a water balance method and the Budyko curve is undertaken to examine the linear relationship. In addition to water supply and energy supply, the primary controls on evapotranspiration, soil water storage, response of vegetation to climate variability, and human interference are also major factors of the interannual relationship between PET/P and ET/P.
Dual Diode Array and Fourier Transform Near Infrared Reflectance Spectrometer Calibrations for Composition Analysis of Single Soybean Seeds for Genetic Selection, Cross-Breeding Experiments
Authors: Baianu I. , You Tiefeng , Nelson Randall
Published: August 2011

Experimental results of extensive evaluations of Diode-Array and FT-NIRS instruments are presented that aim at developing reliable and robust NIR calibrations for single soybean seed composition analysis on both Dual Diode Array and Fourier Transform NIR reflectance instruments. Single soybean seed, bulk, and powder calibrations were developed on four different NIRS spectrometer models that are commercially available.
Influence of microstructure and composition on hydrogenated silicon thin film properties for uncooled microbolometer applications
Authors: Saint John D. B. , Shin H.-B. , Lee M.-Y. , Ajmera S. K. , Syllaios A. J. , Dickey E. C. , Jackson T. N. , Podraza N. J.
Published: August 2011

Doped n- and p-type hydrogenated silicon (Si:H) thin films prepared by plasma enhanced chemical vapor deposition have been investigated for uncooled microbolometer applications. The material microstructure has been studied by in situ real time spectroscopic ellipsometry collected during thin film deposition or ex situ spectroscopic ellipsometry measurements on a static sample with a multiple sample analysis technique. The key electrical properties of interest, including film resistivity (ρ), temperature coefficient of resistance (TCR), and 1/f noise, have been measured as a function of deposition conditions for p-type amorphous hydrogenated silicon (a-Si:H) films and microcrystalline content for n-type amorphous (a), microcrystalline (µc), and mixed-phase amorphous + microcrystalline (a + µc) Si:H films. The TCR and 1/f noise values were compared for p- and n-type a-Si:H samples in the resistivity range of 100 < ρ < 3000 Ω cm and show that for a given resistivity, amorphous p-type films exhibit a lower 1/f noise, which might be expected due to a larger density of majority carriers.
Complex three-dimensional high aspect ratio microfluidic network manufactured in combined PerMX dry-resist and SU-8 technology
Authors: Meier Robert Ch. , Badilita Vlad , Brunne Jens , Wallrabe Ulrike , Korvink Jan G.
Published: August 2011

In this paper we present a new fabrication method that combines for the first time popular SU-8 technology and PerMX dry-photoresist lamination for the manufacturing of high aspect ratio three-dimensional multi-level microfluidic networks. The potential of this approach, which further benefits from wafer-level manufacturing and accurate alignment of fluidic levels, is demonstrated by a highly integrated three-level microfluidic chip. The hereby achieved network complexity, including 24 fluidic vias and 16 crossing points of three individual microchannels on less than 13 mm2 chip area, is unique for SU-8 based fluidic networks. We further report on excellent process compatibility between SU-8 and PerMX dry-photoresist which results in high interlayer adhesion strength. The tight pressure sealing of a fluidic channel (0.5 MPa for 1 h) is demonstrated for 150 μm narrow SU-8/PerMX bonding interfaces.
First order melting transitions of highly ordered dipalmitoyl phosphatidylcholine gel phase membranes in molecular dynamics simulations with atomistic detail
Authors: Schubert Thomas , Schneck Emanuel , Tanaka Motomu
Published: August 2011

Molecular dynamics simulations with atomistic detail of the gel phase and melting transitions of dipalmitoyl phosphatidylcholine bilayers in water reveal the dependency of many thermodynamic and structural parameters on the initial system ordering. We quantitatively compare different methods to create a gel phase system and we observe that a very high ordering of the gel phase starting system is necessary to observe behavior which reproduces experimental data. We performed heating scans with speeds down to 0.5 K/ns and could observe sharp first order phase transitions. Also, we investigated the transition enthalpy as the natural intrinsic parameter of first order phase transitions, and obtained a quantitative match with experimental values. Furthermore, we performed systematic investigations of the statistical distribution and heating rate dependency of the microscopic phase transition temperature.
Influence of biaxial strain on near-band-edge optical properties of c- and a-plane wurtzite-InN films
Authors: Li Yi , Zhang Rong , Liu Bin , Xie Zili , Fu Deyi , Su Hui , Zheng Youdou
Published: August 2011

Optical properties of c- and a-plane wurtzite-InN films with different in-plane strain are investigated by using 8 × 8 k·p method. Taking into account the influence of carrier density, the imaginary parts of ordinary and extraordinary dielectric function of c- and a-plane InN near bandedge are presented. For c-plane InN, the shift of ordinary absorption edge in the case of isotropic in-plane strain in comparison to the unstrained one is very small. For a-plane InN, the splitting between the ordinary and extraordinary components below 1 eV can be modulated with different anisotropic in-plane strain. Furthermore, the difference of splitting between the cases of in-plane strain and strain-free slightly decreases with increasing carrier concentration, which implies the influence of in-plane strain becomes weaker in higher carrier concentration. The spontaneous emission spectrum shows the ratio of peak intensity of y- and z-polarizations increases with enhancement of the splitting. It is considered that the distinct polarization dependent optical anisotropy is expected to be observed in non-polar InN film by appropriately modulating the in-plane strain.
Stability, bifurcations, and dynamics of global variables of a system of bursting neurons
Authors: Franović Igor , Todorović Kristina , Vasović Nebojša , Burić Nikola
Published: August 2011

An approximate mean field model of an ensemble of delayed coupled stochastic Hindmarsh-Rose bursting neurons is constructed and analyzed. Bifurcation analysis of the approximate system is performed using numerical continuation. It is demonstrated that the stability domains in the parameter space of the large exact systems are correctly estimated using the much simpler approximate model.
Effect of packing solid material on characteristics of helium dielectric barrier discharge at atmospheric pressure
Authors: Tu X. , Verheyde B. , Corthals S. , Paulussen S. , Sels B. F.
Published: August 2011

The influence of a solid material (e.g., Al2O3) on the physical characteristics of helium dielectric barrier discharge (DBD) has been investigated in a cylindrical plasma reactor. The helium DBD with the solid packing shows a multiple current-peak effect, which can be ascribed to the enhancement of charge density due to charge deposition on the Al2O3 pellet surface. The combination of plasma and the solid increases both the peak-to-peak voltage and breakdown voltage of the discharge at a fixed input power but decreases the discharge temperature. It is also found that the presence of the solid has a weak effect on the electron temperature and density in the discharge.