bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and spatial representation of synthetic indexes of outpatient mental health care in Andalusia (Spain)
Authors: Garrido-Cumbrera Marco , Almenara-Barrios José , López-Lara Enrique , Peralta-Sáez Juan Luis , García-Gutierrez Juan Carlos , Salvador-Carulla Luis
Published: January 2012

Introduction– There is a need to develop composite indicators to monitor mental health care in countries such as Spain, where there is wide variability of care systems in 17 different regions. The aim of this study is to generate and to test the usability of synthetic indexes in Andalusia (Southern Spain).Method– Seven mental health indicators were selected by expert opinion from a previous list of simple indicators used to compare mental health care systems across Spain (Psicost-74). A Geographical Information Systems (GIS) was used to delineate 71 sectors based on the catchment areas of the mental health centers in Andalusia. Synthetic indexes were obtained through linear combinations of simple indicators via Principal Components Analysis (PCA), using activity data from the Mental Health Information System of Andalusia (SISMA). Maps of these indexes were drawn for 71 catchment areas.Results– Two synthetic indexes were obtained and showed high consistency in the PCA. The Care Load Index (component 1) related to population size and total outpatient care provided within the area. The Case Load Index (component 2) related to assisted morbidity in relation to the population size. The care load index was higher in populated urban areas, whereas the case load was higher in rural areas.Discussion– Care and case load indexes show a different pattern in urban and rural areas. This may be related to a different underlying model of care related to the degree of urbanisation. Geographical Information Systems (GIS) improved recognition and assessment of the spatial phenomena related to the mental health care system, and support policy decision making process in mental health.

Declaration of Interest:None.
Measurement validity in cross-cultural comparative research
Authors: Prince Martin
Published: January 2012

Background– The purpose of this article is to review the procedures to establish measurement validity in crosscultural comparative research, including recent developments in the quantitative assessment of cross-cultural construct validity.Methods– A narrative review, illustrated by selected examples, of methods in four areas – formative conceptual research, translation and adaptation, criterion validity and construct validity.Results– Valid assessment across cultures requires qualitative research to investigate the cultural relevance of the construct, a careful translation and adaptation of a common measure, followed by pre-testing and cognitive interviews on the populations to be tested. Full criterion validation across diverse cultures may be a chimera given the difficulty in establishing a universally applicable ‘gold standard'. Quantitative analyses can, however, have a part to play in establishing construct validity across cultures. Scale internal consistency, inter-item and item-total correlations and test-retest reliability provide basic support for the viability of a measure in a new cultural setting. Exploratory factor analysis can be used to compare factors and factor loadings. The hypothesis of ‘measurement invariance’ across countries and cultures can be tested explicitly using confirmatory factor analysis (common underlying factors and factor loadings) and Rasch models (common hierarchality of items). Despite measurement invariance, threshold effects arising from cultural differences in norms, or expectations, or expressions of mental distress may still be a problem.Conclusions– There are few examples in the cross-cultural mental health literature of demonstrably valid culture-fair comparison. Much more, could, in principle, be done either to demonstrate measurement invariance, or to identify and explore sources of heterogeneity.

Declaration of Interest: None.
The descriptive epidemiology of suicide in Tuscany, 1988-2002
Authors: Martiello Michele Arcangelo , Cipriani Francesco , Voller Fabio , Buiatti Eva , Giacchi Mariano
Published: January 2012

Aims – To describe the epidemiology of Suicide in Tuscany according to the triad of time, place and person. Methods – The 4, 764 cases of suicide, defined according to categories E950-E959 of ICD-9 in Tuscany over the period 1988–2002, were obtained from the Tuscan Mortality Register. Mortality indicators were calculated and analyzed. The spatial analysis was carried out by deriving Empirical Bayes Estimates for the 287 municipalities. Results – The crude mortality rate in the 2000–2002 is 7.8 per 100000 population (male: 12.4; female: 3.5). The age-standardized rate in the 2000–2002 is 5.8 per 100, 000 population (male: 9.6; female: 2.6). The highest risk for suicide, especially in the case of males, are concentrated in the southern hinterland Tuscany, in a cluster of rural municipalities that represent the old mining district of Tuscany. The SMRs according to residential municipality (population per square kilometre), confirm a greater risk of suicide for males residing in rural communities. Conclusions – The cluster of excessive mortality from suicide in Southern Tuscany could be the consequence of social determinants, related to the urban and social crisis following agriculture decline and mine closure.

Declaration of Interest: none.
Problematising the Relationship between Teenage Boys and Parent Abuse: Constructions of Masculinity and Violence
Authors: Baker Helen
Published: January 2012

Although research into parent abuse is scant in the context of the UK, there is now a burgeoning of interest into how this form of family violence fits into the historically well-defined arena of domestic violence research. This article investigates one aspect of the phenomena of parent abuse; that is, how teenage boys, who are often perceived as perpetrators of such violence due to problematic ‘cycle of violence’ or ‘intergenerational transmission of violence’ theories, are constructed in relation to it. These now widely discredited theories, which correlate being a man with being violent, are problematic, but may re-emerge as a possible explanation for parent abuse. This article questions these theories in the context of both domestic violence and parent abuse by demonstrating how they are based upon a culturally constructed notion of masculinity.
Response to Scott Barrett's review of Precautionary Politics: Principle and Practice in Confronting Environmental Risk
Authors: Whiteside Kerry H.
Published: January 2012

As in his book, Scott Barrett seizes the reader's interest by describing a dramatic situation of choice. Who cannot be struck by the example of the Large Hadron Collider and the possibility of accidentally annihilating the Earth with it? What does precaution require here?
Choice policies in Northern European health systems
Authors: Vrangbaek Karsten , Robertson Ruth , Winblad Ulrika , Van de Bovenkamp Hester , Dixon Anna
Published: January 2012

This paper compares the introduction of policies to promote or strengthen patient choice in four Northern European countries – Denmark, England, the Netherlands and Sweden. The paper examines whether there has been convergence in choice policies across Northern Europe. Following Christopher Pollitt's suggestion, the paper distinguishes between rhetorical (discursive) convergence, decision (design) convergence and implementation (operational) convergence (Pollitt, 2002). This leads to the following research question for the article: Is the introduction of policies to strengthen choice in the four countries characterised by discursive, decision and operational convergence? The paper concludes that there seems to be convergence among these four countries in the overall policy rhetoric about the objectives associated with patient choice, embracing both concepts of empowerment (the intrinsic value) and market competition (the instrumental value). It appears that the institutional context and policy concerns such as waiting times have been important in affecting the timing of the introduction of choice policies and implementation, but less so in the design of choice policies. An analysis of the impact of choice policies is beyond the scope of this paper, but it is concluded that further research should investigate how the institutional context and timing of implementation affect differences in how the choice policy works out in practice.
Modeling the Miocene climatic optimum: Ocean circulation
Authors: Herold N. , Huber M. , Müller R. D. , Seton M.
Published: January 2012

Ocean circulation is investigated using the Community Climate System Model 3 (CCSM3) forced with early to middle Miocene (∼20–14 Ma) topography, bathymetry, vegetation and modern CO2. Significant bottom water formation is modeled in the Weddell Sea along with intermediate North Component Water formation in the North Atlantic. This is attributed primarily to stronger‐ and weaker‐than‐modern convective preconditioning in the Weddell and Labrador Seas, respectively. Global meridional overturning and gyre circulation is weaker in the Miocene due to weaker midlatitude westerlies in the southern hemisphere, caused by lowering of the meridional surface temperature gradient, in addition to regional influences on convection. Subsurface temperatures in the Miocene are significantly higher in the far North Atlantic, Greenland‐Norwegian Seas and Arctic basin compared to the present. Ocean heat transport is symmetrical about the equator and resembles that simulated for late Cretaceous and early Cenozoic climates, suggesting the northern hemisphere dominated ocean heat transport active today developed after the middle Miocene. Simulated deep water warming in the Miocene is more than an order of magnitude lower than indicated by proxies. This discrepancy is not reconciled by higher CO2 due to the persistence of sea‐ice at sites of deep water formation. This suggests that either the CCSM3 is insufficiently sensitive to Miocene boundary conditions, greater greenhouse forcing existed than is currently reconstructed, or that proxy records of warming are exaggerated. Given the diversity of global Miocene proxy records and their near‐unanimous estimate of a significantly warmer Earth, the first two options are more likely.
Subseafloor nitrogen transformations in diffuse hydrothermal vent fluids of the Juan de Fuca Ridge evidenced by the isotopic composition of nitrate and ammonium
Authors: Bourbonnais Annie , Lehmann Moritz F. , Butterfield David A. , Juniper S. Kim
Published: January 2012

Little is known about dissolved inorganic nitrogen (DIN) transformations in hydrothermal vent (HV) fluids. Here, we present the first isotopic measurements of nitrate (δ15N and δ18O) and ammonium (δ15N) from three HV fields on the Juan de Fuca ridge (NE‐Pacific). The dominant process that drives DIN concentration variations in low‐T diffuse fluids is water mass mixing below the seafloor, with no effect on the DIN isotope ratios. Strong inter‐site variations in the concentration andδ15N of NH4+in high‐T fluids suggest different subsurface nitrogen (N) sources (deep‐sea nitrate versus organic sediments) for hydrothermally discharged ammonium. Low NH4+ community N isotope effects (<3‰) for net NH4+consumption suggest an important contribution from gross ammonium regeneration in low‐T fluids. Elevation of HV nitrate15N/14N and 18O/16O over deep‐sea mean isotope values at some sites, concomitant with decreased nitrate concentrations, indicate assimilatory or dissimilatory nitrate consumption by bacteria in the subsurface, with relatively low community N isotope effects (15εk < 3‰). The low N isotope effects suggest that nitrate assimilation or denitrification occur in bacterial mats, and/or in situ production of low δ15N nitrate. A significantly stronger relative increase for nitrate δ18O than for δ15N was observed at many sites, resulting in marked deviations from the 1:1 relationship for nitrate δ15N versus δ18O that is expected for nitrate reduction in marine settings. Simple box‐model calculation show that the observed un‐coupling of N and O nitrate isotope ratios is consistent with nitrate regeneration by either nitrite reoxidation and/or partial nitrification of hydrothermal ammonium (possibly originating from N2 fixation). Our isotope data confirm the role of subsurface microbial communities in modulating hydrothermal fluxes to the deep ocean.
Real time monitoring of moment magnitude by waveform inversion
Authors: Lee J. , Friederich W. , Meier T.
Published: January 2012

An instantaneous measure of the moment magnitude (Mw) of an ongoing earthquake is estimated from the moment rate function (MRF) determined in real‐time from available seismic data using waveform inversion. Integration of the MRF gives the moment function from which an instantaneousMw is derived. By repeating the inversion procedure at regular intervals while seismic data are coming in we can monitor the evolution of seismic moment and Mw with time. The final size and duration of a strong earthquake can be obtained within 12 to 15 minutes after the origin time. We show examples of Mw monitoring for three large earthquakes at regional distances. The estimated Mw is only weakly sensitive to changes in the assumed source parameters. Depending on the availability of seismic stations close to the epicenter, a rapid estimation of the Mw as a prerequisite for the assessment of earthquake damage potential appears to be feasible.
Normal‐faulting earthquakes beneath the outer slope of the Japan Trench after the 2011 Tohoku earthquake: Implications for the stress regime in the incoming Pacific plate
Authors: Obana Koichiro , Fujie Gou , Takahashi Tsutomu , Yamamoto Yojiro , Nakamura Yasuyuki , Kodaira Shuichi , Takahashi Narumi , Kaneda Yoshiyuki , Shinohara Masanao
Published: January 2012

After the 2011 Mw 9.1 Tohoku earthquake, numerous intraplate earthquakes occurred beneath the outer slope of the Japan Trench. Based on ocean bottom seismograph observations, these earthquakes occurred in the oceanic crust and uppermost mantle of the Pacific plate at depths shallower than about 40 km and had normal‐faulting focal mechanisms at all depths. Before the 2011 earthquake, normal‐faulting earthquakes beneath the outer trench slope occurred only at depths shallower than 20 km, whereas those at depths of around 40 km had reverse‐faulting mechanisms. These observations suggest that the stress regime in the Pacific plate was changed by the 2011 earthquake. The tensional stresses that now extend to depths of about 40 km may play an important role not only in the occurrence of large normal‐faulting earthquakes but also in hydration of the uppermost mantle of the incoming Pacific plate prior to the subduction.
Saturation dependence of the quadrature conductivity of oil‐bearing sands
Authors: Schmutz M. , Blondel A. , Revil A.
Published: January 2012

We have investigated the complex conductivity of oil‐bearing sands with six distinct oil types including sunflower oil, silicone oil, gum rosin, paraffin, engine oil, and an industrial oil of complex composition. In all these experiments, the oil was the non‐wetting phase. The in‐phase (real) conductivity follows a power law relationship with the saturation (also known as the second Archie's law) but with a saturation exponentn raging from 1.1 to 3.1. In most experiments, the quadrature conductivity follows also a power law relationship with the water saturation but with a power law exponent p can be either positive or negative. For some samples, the quadrature conductivity first increases with saturation and then decreases indicating that two processes compete in controlling the quadrature conductivity. One is related to the insulating nature of the oil phase and a second could be associated with the surface area of the oil / water interface. The quadrature conductivity seems to be influenced not only by the value of the saturation exponent n (according to the Vinegar and Waxman model, p = n− 1), but also by the surface area between the oil phase and the water phase especially for very water‐repellent oil having a fractal oil–water interface.
Permeability correction factor for fractures with permeable walls
Authors: Mohais R. , Xu C. , Dowd P. A. , Hand M.
Published: January 2012

Enhanced Geothermal Systems (EGS) are based on the premise that heat can be extracted from hot dry rocks located at significant depths by circulating fluid through fracture networks in the system. Heated fluid is recovered through production wells and the energy is extracted in a heat exchange chamber. There is much published research on flow through fractures, and many models have been developed to describe an effective permeability of a fracture or a fracture network. In these cases however, the walls of the fracture were modelled as being impermeable. In this paper, we have extended our previous work on fractures with permeable walls, and we introduce a correction factor to the equation that governs fracture permeability. The solution shows that the effective fracture permeability for fractures with permeable walls depends not only on the height of the channel, but also on the wall permeability and the wall Reynolds number of the fluid. We show that our solution reduces to the established solution when the fracture walls become impermeable. We also extend the discussion to cover the effective permeability of a system of fractures with permeable walls.
Wave‐particle interaction in a plasmaspheric plume observed by a Cluster satellite
Authors: Yuan Zhigang , Xiong Ying , Pang Ye , Zhou Meng , Deng Xiaohua , Trotignon Jean Gabriel , Lucek Elizabeth , Wang Jingfang
Published: January 2012

The wave‐particle interaction is a possible candidate for the energy coupling between the ring current and plasmaspheric plumes. In this paper, we present wave and particle observations made by the Cluster C1 satellite in a plasmaspheric plume in the recovery phase of the geomagnetic storm on 18 July 2005. Cluster C1 simultaneously observed Pc1‐2 waves and extremely low frequency (ELF) hiss in the plasmaspheric plume. Through an analysis of power spectral density and polarization of the perturbed magnetic field, we identify that the observed Pc1‐2 waves are linearly polarized electromagnetic ion cyclotron (EMIC) waves and show that the ELF hiss propagates in the direction of the ambient magnetic field in whistler mode. In the region where the EMIC waves were observed, the pitch angle distribution of ions becomes more isotropic, likely because of the pitch angle scattering by the EMIC waves. It is shown that the ELF hiss and EMIC waves are spatially separated: The ELF hiss is located in the vicinity of the electron density peak within the plume while the EMIC waves are detected in the outer boundary of the plume because of the different propagation characteristics of the ELF hiss and EMIC waves.
The effect of ∼27 day solar rotation on ionospheric F2 region peak densities (NmF2)
Authors: Ma Ruiping , Xu Jiyao , Wang Wenbin , Lei Jiuhou
Published: January 2012

Ionospheric F2 region peak electron densities (NmF2) observed from 11 ionosonde stations in the East Asian‐Australian sector from 1969 to 1986 have been used to investigate the effect of ∼27 day solar rotation on the ionosphere. These stations were located from the magnetically equatorial regions to the middle latitudes in both hemispheres. We found that, averaged over all stations and for 18 years, the normalized standard deviation of the midday ∼27 day variations of NmF2 was 8% and that of the midnight variations was 10%. We applied different data analysis methods, including Fourier transform, band‐pass filter, and multiple linear regression analysis, to determine quantitatively the sources of the observed ∼27 day variations of NmF2 and their relative contributions to these variations. Our results show that the ∼27 day variations in solar radiation and geomagnetic activity, caused by solar rotation, are the main drivers of the ionospheric ∼27 day variations. They accounted for more than 85% of the variations seen in the NmF2 ∼27 day variation, and their contributions became about 95% at higher latitudes. At geomagnetically low latitudes, the contribution of the ∼27 day variation in solar EUV radiation was greater than that of the ∼27 day variation in geomagnetic activity. However, the contribution from geomagnetic activity became more significant and was even larger than the contribution of solar radiation at higher latitudes, especially at midnight. At all latitudes the correlation between the ∼27 day variations of NmF2 and solar radiation was evidently positive, whereas that between NmF2 and geomagnetic activity was positive at geomagnetically low latitudes and became negative at higher middle latitudes. We did not found large seasonal or solar cycle changes in the ∼27 day variations of NmF2. These variations, however, did show significant differences between the two hemispheres.
Transdimensional inverse thermal history modeling for quantitative thermochronology
Authors: Gallagher Kerry
Published: January 2012

A new approach for inverse thermal history modeling is presented. The method uses Bayesian transdimensional Markov Chain Monte Carlo and allows us to specify a wide range of possible thermal history models to be considered as general prior information on time, temperature (and temperature offset for multiple samples in a vertical profile). We can also incorporate more focused geological constraints in terms of more specific priors. The Bayesian approach naturally prefers simpler thermal history models (which provide an adequate fit to the observations), and so reduces the problems associated with over interpretation of inferred thermal histories. The output of the method is a collection or ensemble of thermal histories, which quantifies the range of accepted models in terms a (posterior) probability distribution. Individual models, such as the best data fitting (maximum likelihood) model or the expected model (effectively the weighted mean from the posterior distribution) can be examined. Different data types (e.g., fission track, U‐Th/He,40Ar/39Ar) can be combined, requiring just a data‐specific predictive forward model and data fit (likelihood) function. To demonstrate the main features and implementation of the approach, examples are presented using both synthetic and real data.
On the nature of short‐period mesospheric gravity wave propagation over Halley, Antarctica
Authors: Nielsen K. , Taylor M. J. , Hibbins R. E. , Jarvis M. J. , Russell J. M.
Published: January 2012

As part of a collaborative program between British Antarctic Survey and Utah State University, measurements were made using an all‐sky airglow imager located at the U.K. Halley Station (76°S, 27°W) during the 2000 and 2001 austral winter seasons from April through to early September. A co‐located imaging Doppler interferometer was utilized to obtain coincident wind measurements for a total of 171 wave events. This study comprises the first detailed climatological investigation of the propagation nature (freely propagating, Doppler ducted, or evanescent) of individual quasi‐monochromatic, short‐period wave events at a high southern latitude. Distributions of the derived vertical wavelength exhibit an interquartile range from ∼16–48 km with a median vertical wavelength of 21 km. The majority of the wave events were found to be freely propagating waves, with only ∼5% exhibiting a clear Doppler ducted signature, while 15% of the waves were found to be evanescent in nature. Although no coincident temperature measurements were available, subsequent SABER temperature measurements suggest that up to ∼28% of the measured temperature profiles are capable of providing a ducted environment for the observed wave field. This is in sharp contrast to findings at mid‐ and low latitudes where these waves have been shown to be prone to Doppler ducted motion. It is suggested that the relatively weak wind field and associated tidal wind amplitudes over Halley are not capable of forming a significant Doppler ducted region to sustain a substantial amount of ducted waves belonging to the detectable spectrum of the airglow imager. As these wind fields are comparable to wind fields found at other polar latitudes, we hypothesize that the majority of short‐period gravity waves observed in the polar mesosphere are freely propagating and thus an important source of energy transfer into the MLT region.
Discharge height of lightning narrow bipolar events
Authors: Wu Ting , Dong Wansheng , Zhang Yijun , Funaki Tsuyoshi , Yoshida Satoru , Morimoto Takeshi , Ushio Tomoo , Kawasaki ZenIchiro
Published: January 2012

Discharge heights of thousands of narrow bipolar events (NBEs) observed in Guangzhou and Chongqing of China are calculated using time delays between the direct wave signals of NBEs and their ionospheric reflection pairs. The result shows that most positive NBEs occur between 8 and 16 km while most negative NBEs occur between 16 and 19 km. Very few negative NBEs are above 19 km or below 14 km. It is inferred that positive NBEs are produced between main negative charge layer and upper positive charge layer while negative NBEs are produced between upper positive charge layer and negative screening charge layer at the cloud top. Variations of NBE discharge heights in two thunderstorms are analyzed. It seems that NBEs can be produced at any position between corresponding charge layers. Positive NBEs are generally higher in the periods when negative NBEs are also occurring. For a given short time period in a single thunderstorm, negative NBEs are always observed to occur at a higher altitude than positive NBEs, indicating a dividing charge layer between positive NBEs and negative NBEs. The possibility of some NBEs as upward discharges from cloud tops mentioned by previous studies is discussed. Supported by multiple evidences, we believe such possibility is very low; instead, NBEs are produced in vigorous convective surges that develop to the height comparable to the discharge height of NBEs. Differences in height distributions in Guangzhou and Chongqing are analyzed and a hypothesis is put forward that both positive NBEs and negative NBEs can only be produced above certain height. The relationship between this hypothesis and the mechanism for NBE production is discussed.
Large amplitude spatial and temporal gradients in atmospheric boundary layer CO2mole fractions detected with a tower‐based network in the U.S. upper Midwest
Authors: Miles Natasha L. , Richardson Scott J. , Davis Kenneth J. , Lauvaux Thomas , Andrews Arlyn E. , West Tristram O. , Bandaru Varaprasad , Crosson Eric R.
Published: January 2012

This study presents observations of atmospheric boundary layer CO2mole fraction from a nine‐tower regional network deployed during the North American Carbon Program's Mid‐Continent Intensive (MCI) during 2007–2009. The MCI region is largely agricultural, with well‐documented carbon exchange available via agricultural inventories. By combining vegetation maps and tower footprints, we show the fractional influence of corn, soy, grass, and forest biomes varies widely across the MCI. Differences in the magnitude of CO2 flux from each of these biomes lead to large spatial gradients in the monthly averaged CO2mole fraction observed in the MCI. In other words, the monthly averaged gradients are tied to regional patterns in net ecosystem exchange (NEE). The daily scale gradients are more weakly connected to regional NEE, instead being governed by local weather and large‐scale weather patterns. With this network of tower‐based mole fraction measurements, we detect climate‐driven interannual changes in crop growth that are confirmed by satellite and inventory methods. These observations show that regional‐scale CO2 mole fraction networks yield large, coherent signals governed largely by regional sources and sinks of CO2.
Controls on the composition and lability of dissolved organic matter in Siberia's Kolyma River basin
Authors: Mann P. J. , Davydova A. , Zimov N. , Spencer R. G. M. , Davydov S. , Bulygina E. , Zimov S. , Holmes R. M.
Published: January 2012

High‐latitude northern rivers export globally significant quantities of dissolved organic carbon (DOC) to the Arctic Ocean. Climate change, and its associated impacts on hydrology and potential mobilization of ancient organic matter from permafrost, is likely to modify the flux, composition, and thus biogeochemical cycling and fate of exported DOC in the Arctic. This study examined DOC concentration and the composition of dissolved organic matter (DOM) across the hydrograph in Siberia's Kolyma River, with a particular focus on the spring freshet period when the majority of the annual DOC load is exported. The composition of DOM within the Kolyma basin was characterized using absorbance‐derived measurements (absorbance coefficienta330, specific UV absorbance (SUVA254), and spectral slope ratio SR) and fluorescence spectroscopy (fluorescence index and excitation‐emission matrices (EEMs)), including parallel factor analyses of EEMs. Increased surface runoff during the spring freshet led to DOM optical properties indicative of terrestrial soil inputs with high humic‐like fluorescence, SUVA254, and low SRand fluorescence index (FI). Under‐ice waters, in contrast, displayed opposing trends in optical properties representing less aromatic, lower molecular weight DOM. We demonstrate that substantial losses of DOC can occur via biological (∼30% over 28 days) and photochemical pathways (>29% over 14 days), particularly in samples collected during the spring freshet. The emerging view is therefore that of a more dynamic and labile carbon pool than previously thought, where DOM composition plays a fundamental role in controlling the fate and removal of DOC at a pan‐Arctic scale.
Solute transport and retention in three‐dimensional fracture networks
Authors: Cvetkovic Vladimir , Frampton Andrew
Published: January 2012

Resolving the hydrodynamic control of retention is an important step in predictive modeling of transport of sorbing tracers in fractured rock. The statistics of the transport resistance parameter β [T/L] and the related effective active specific surface area sf [1/L] are studied in a crystalline rock volume on a 100 m scale. Groundwater flow and advective transport are based on generic boundary conditions and realistic discrete fracture networks inferred from the Laxemar site, southeast Sweden. The overall statistics of β are consistent with statistics of the water residence time τ; the moments of β vary linearly with distance, at least up to 100 m. The correlation between log τ and log β is predominantly linear, however, there is significant dispersion; the parameter sf strongly depends on the assumed hydraulic law (theoretical cubic or empirical quadratic). Fast and slow trajectories/segments in the network determine the shape of the β distribution that cannot be reproduced by infinitely divisible model over the entire range; the low value range and median can be reproduced reasonably well with the tempered one‐sided stable density using the exponent in the range 0.35–0.7. The low percentiles of the β distribution seems to converge to a Fickian type of behavior from a 50 to 100 m scale.
Assurance of mitochondrial integrity and mammalian longevity by the p62–Keap1–Nrf2–Nqo1 cascade
Authors: Kwon Jeongho , Han Eunhye , Bui Chi‐Bao , Shin Woochul , Lee Junho , Lee Sejeong , Choi Young‐Bong , Lee Ann‐Hwee , Lee Kyong‐Hoon , Park Chankyu , Obin Martin S , Park Sung Kyu , Seo Yun Jeong , Oh Goo Taeg , Lee Han‐Woong , Shin Jaekyoon
Published: January 2012

Sqstm1/p62 functions in the non‐canonical activation of nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2). However, its physiological relevance is not certain. Here, we show that p62−/− mice exhibited an accelerated presentation of ageing phenotypes, and tissues from these mice created a pro‐oxidative environment owing to compromised mitochondrial electron transport. Accordingly, mitochondrial function rapidly declined with age in p62−/− mice. In addition, p62 enhanced basal Nrf2 activity, conferring a higher steady‐state expression of NAD(P)H dehydrogenase, quinone 1 (Nqo1) to maintain mitochondrial membrane potential and, thereby, restrict excess oxidant generation. Together, the p62–Nrf2–Nqo1 cascade functions to assure mammalian longevity by stabilizing mitochondrial integrity.
Retention and transmission of active transcription memory from progenitor to progeny cells via ligand‐modulated transcription factors: elucidation of a concept by BIOPIT model
Authors: Kumar Sanjay , Saradhi Mallampati , Chaturvedi Nagendra K. , Tyagi Rakesh K.
Published: January 2012

Observations made in live cells have clearly demonstrated that agonist‐activated steroid/nuclear receptors reorganize in the nucleoplasm into hundreds of discrete speckled structures commonly referred to as nuclear foci. Subsequent studies have shown that nuclear foci are formed only with agonist‐ and not with pure antagonist‐bound receptors. Also, the other accessory components of transcriptional machinery co‐localize in nuclear foci with the activated receptors, suggesting these to be active gene transcription sites. Recently, it has been observed that during mitosis nuclear foci present in interphase of progenitor cells co‐migrate with condensing chromatin and are inherited into the progeny cells. Ensuing events imply that as memory, the cells inherit only a biomolecular blueprint of transcription status over to next generations to express and sustain their characteristic proteome. Thus, cells achieve self‐renewal via mitosis but not without ensuring that the characteristic proteome and traits are distinctively preserved during this transcription phase. This mechanism, although somewhat analogous to epigenetic marking, differs in Nature since transcription factors themselves execute this transmission. To uphold the mechanistic distinctions the phenomenon has been termed BIOPIT (biomolecular imprints offered to progeny for inheritance of traits). The BIOPIT model proposed herein attempts to explain how the disruption of BIOPIT markings by therapeutic anti‐hormones or endocrine disruptors over prolonged periods may lead to eradication of cellular transcription memory with deleterious cellular consequences. It is anticipated that our model has the potential to explain the concerted actions and consequences of ligand—receptor interactions with the chromatin in the perspective of normal and aberrant physiological situations.
A Kinematic Description of the Temporal Characteristics of Jaw Motion for Early Chewing: Preliminary Findings
Authors: Wilson Erin M. , Green Jordan R. , Weismer Gary
Published: January 2012

Purpose

The purpose of this investigation was to describe age- and consistency-related changes in the temporal characteristics of chewing in typically developing children between the ages of 4 and 35 months and adults using high-resolution optically based motion capture technology.

Method

Data were collected from 60 participants (48 children, 12 adults) across 5 age ranges (beginners, 7 months, 12 months, 35 months, and adults); each age group included 12 participants. Three different food consistencies were trialed as appropriate. The data were analyzed to assess changes in chewing rate, chewing sequence duration, and estimated number of chewing cycles.

Results

The results revealed both age- and consistency-related changes in chewing rate, sequence duration, and estimated number of chewing cycles, with consistency differences affecting masticatory timing in children as young as 7 months of age. Chewing rate varied as a function of age and consistency, and chewing sequence duration was shorter for adults than for children regardless of consistency type. In addition, the results from the estimated number of chewing cycles measure suggest that chewing effectiveness increased with age; this measure was also dependent on consistency type.

Conclusions

The findings suggest that the different temporal chewing variables follow distinct developmental trajectories and are consistency dependent in children as young as 7 months of age. Clinical implications are detailed.
Nonword Repetition: The Relative Contributions of Phonological Short-Term Memory and Phonological Representations in Children With Language and Reading Impairment
Authors: Rispens Judith , Baker Anne
Published: January 2012

Purpose

This study investigates the relative contributions of phonological short-term memory and phonological representations to nonword repetition (NWR). This was evaluated in children with specific language impairment (SLI) and/or reading impairment (RI); it was also studied from a developmental perspective by comparing 2 groups of typically developing (TD) children who differed in age.

Method

NWR, digit span, vocabulary, and word and nonword discrimination were tested in 2 groups of TD children: one group matched on chronological age (CA TD group:
n
= 41, mean age = 7;8 [months;years]), and one language age–matched control group (LA TD group:
n
= 16, mean age = 5;8). Also, 10 children with SLI, 14 children with RI, and 23 children with SLI and RI (hereafter, SLI + RI) participated and were matched to the age of the CA TD group.

Results

For the TD children, NWR was predicted by discrimination, digit span, and age. The interaction between discrimination ability and age was also significant. Children with SLI + RI were significantly impaired on NWR compared with all other groups. A regression analysis, including the CA TD group and the children with SLI and/or RI, showed that digit span, discrimination ability, and group (SLI + RI) contributed significantly to NWR.

Conclusions

Phonological short-term memory and phonological representations both significantly contribute to NWR. The predictive strength of the quality of phonological representations changes during development.
Solid effect dynamic nuclear polarization and polarization pathways
Authors: Smith Albert A. , Corzilius Björn , Barnes Alexander B. , Maly Thorsten , Griffin Robert G.
Published: January 2012

Using dynamic nuclear polarization (DNP)/nuclear magnetic resonance instrumentation that utilizes a microwave cavity and a balanced rf circuit, we observe a solid effect DNP enhancement of 94 at 5 T and 80 K using trityl radical as the polarizing agent. Because the buildup rate of the solid effect increases with microwave field strength, we obtain a sensitivity gain of 128. The data suggest that higher microwave field strengths would lead to further improvements in sensitivity. In addition, the observation of microwave field dependent enhancements permits us to draw conclusions about the path that polarization takes during the DNP process. By measuring the time constant for the polarization buildup and enhancement as a function of the microwave field strength, we are able to compare models of polarization transfer, and show that the major contribution to the bulk polarization arises via direct transfer from electrons, rather than transferring first to nearby nuclei and then transferring to bulk nuclei in a slow diffusion step. In addition, the model predicts that nuclei near the electron receive polarization that can relax, decrease the electron polarization, and attenuate the DNP enhancement. The magnitude of this effect depends on the number of near nuclei participating in the polarization transfer, hence the size of the diffusion barrier, their T1, and the transfer rate. Approaches to optimizing the DNP enhancement are discussed.
Electrotaxis of lung cancer cells in ordered three-dimensional scaffolds
Authors: Sun Yung-Shin , Peng Shih-Wei , Lin Keng-Hui , Cheng Ji-Yen
Published: January 2012

In this paper, we report a new method to incorporate 3D scaffold with electrotaxis measurement in the microfluidic device. The electrotactic response of lung cancer cells in the 3D foam scaffolds which resemble the in vivo pulmonary alveoli may give more insight on cellular behaviors in vivo. The 3D scaffold consists of ordered arrays of uniform spherical pores in gelatin. We found that cell morphology in the 3D scaffold was different from that in 2D substrate. Next, we applied a direct current electric field (EF) of 338 mV/mm through the scaffold for the study of cells’ migration within. We measured the migration directedness and speed of different lung cancer cell lines, CL1-0, CL1-5, and A549, and compared with those examined in 2D gelatin-coated and bare substrates. The migration direction is the same for all conditions but there are clear differences in cell morphology, directedness, and migration speed under EF. Our results demonstrate cell migration under EF is different in 2D and 3D environments and possibly due to different cell morphology and/or substrate stiffness.
Super extension of Bell polynomials with applications to supersymmetric equations
Authors: Fan Engui , Hon Y. C.
Published: January 2012

In this paper, we generalize classical Bell polynomials into super version, which are found to be effective in systematically constructing super bilinear representation, bilinear Bäcklund transformation, Lax pair, and infinite conservation laws of supersymmetric equations. We take \documentclass[12pt]{minimal}\begin{document}$\mathcal{N}=1$\end{document}N=1 supersymmetric KdV equation and \documentclass[12pt]{minimal}\begin{document}$\mathcal{N}=2$\end{document}N=2 supersymmetric sine-Gordon equation to illustrate this procedure.
Biocompatible ferroelectric (Na,K)NbO3 nanofibers
Authors: Jalalian A. , Grishin A. M.
Published: January 2012

Dense homogeneous textile composed from continuous bead-free sodium potassium niobate (NKN) nanofibers 100 μm long and 50-200 nm in diameter was sintered by sol-gel calcination assisted electrospinning. High resolution electron microscopy and x-ray diffraction revealed preferential cube-on-cube growth of fibers in [001] direction. Raman spectrum of NKN fibers contains all the features characteristic to electrically poled orthorhombic phase. In contrast to polycrystalline ceramics, it shows relative enhancement of the Raman cross section of isotropic A1g(ν1) mode compared with polar axis defined F2g(ν5) and Eg(ν2) vibrations. We interpret this as an evidence for superparaelectric state of NKN nanofibers. Spontaneous polarization inside highly crystalline nanofiber exists at room temperature though big distance between fibers prevents the settling of a net macroscopic polarization.
Stockholder projector analysis: A Hilbert-space partitioning of the molecular one-electron density matrix with orthogonal projectors
Authors: Vanfleteren Diederik , Van Neck Dimitri , Bultinck Patrick , Ayers Paul W. , Waroquier Michel
Published: January 2012

A previously introduced partitioning of the molecular one-electron density matrix over atoms and bonds [D. Vanfleteren et al., J. Chem. Phys. 133, 231103 (2010)] is investigated in detail. Orthogonal projection operators are used to define atomic subspaces, as in Natural Population Analysis. The orthogonal projection operators are constructed with a recursive scheme. These operators are chemically relevant and obey a stockholder principle, familiar from the Hirshfeld-I partitioning of the electron density. The stockholder principle is extended to density matrices, where the orthogonal projectors are considered to be atomic fractions of the summed contributions. All calculations are performed as matrix manipulations in one-electron Hilbert space. Mathematical proofs and numerical evidence concerning this recursive scheme are provided in the present paper. The advantages associated with the use of these stockholder projection operators are examined with respect to covalent bond orders, bond polarization, and transferability.
Large thermal Hall coefficient in bismuth
Authors: Kobayashi W. , Koizumi Y. , Moritomo Y.
Published: January 2012

We present a systematical study of thermal Hall effect on a bismuth single crystal by measuring resistivity, Hall coefficient, and thermal conductivity under magnetic field, which shows a large thermal Hall coefficient comparable to the largest one in a semiconductor HgSe. We discuss that this is mainly due to a large mobility and a low thermal conductivity comparing theoretical calculations, which will give a route for controlling heat current in electronic devices.
Independent tuning of electron and hole confinement in InAs/GaAs quantum dots through a thin GaAsSbN capping layer
Authors: Ulloa J. M. , Reyes D. F. , Montes M. , Yamamoto K. , Sales D. L. , González D. , Guzman A. , Hierro A.
Published: January 2012

The possibility of an independent tuning of the electron and hole confinement in InAs/GaAs quantum dots (QDs) by using a thin GaAsSbN capping layer (CL) is studied. By controlling the Sb and N contents in the quaternary alloy, the band structure of the QDs can be broadly tuned and converted from type-II in the valence band (high Sb contents) to type-I and to type-II in the conduction band (high N contents). Nevertheless, the simultaneous presence of Sb and N is found to induce strain and composition inhomogeneities in the CL and to degrade the photoluminescence of the structure.
Nano-opto-mechanical actuator driven by gradient optical force
Authors: Cai H. , Xu K. J. , Liu A. Q. , Fang Q. , Yu M. B. , Lo G. Q. , Kwong D. L.
Published: January 2012

In this letter, a nanoscale opto-mechanical actuator driven by gradient optical force is designed and demonstrated. The nanoscale actuator can achieve a maximum displacement of 67 nm with a response time of 94.5 ns. The optical force is estimated as 1.01 pN/μm/mW in C-band operating wavelengths. The device is fabricated on silicon-on-insulator wafer using standard dry etching processes. Compared with traditional microelectromechanical systems actuators driven by electrostatic force, the nanoscale opto-mechanical actuator has the advantages of high resolution of actuation, nanoscale displacement, and fast operating speed. It has potential applications in optical signal processing, chemical, and biological sensing.
Band gap widening with time induced by structural relaxation in amorphous Ge2Sb2Te5 films
Authors: Fantini P. , Brazzelli S. , Cazzini E. , Mani A.
Published: January 2012

In a phase change memory the device resistance corresponding to the amorphous phase monotonically increases with time after the reset programming operation. This phenomenon, called drift, affects the stability of the high resistive state, namely the reset state. In this work we investigate the resistance-drift process through ellipsometric measurements as a function of time in thin film of as-deposited amorphous Ge2Sb2Te5 alloy. We show a tight correlation between the resistance increase with time and the optical band gap widening extracted by ellipsometric measurements. This characterization supports the drift origin due to a structural atomic rearrangement of the amorphous network affecting the band structure that, in particular, promotes the increase of the energy gap and the reduction of localized states within the energy gap.
X-ray luminescence of CdTe quantum dots in LaF3:Ce/CdTe nanocomposites
Authors: Hossu Marius , Liu Zhongxin , Yao Mingzhen , Ma Lun , Chen Wei
Published: January 2012

CdTe quantum dots have intense photoluminescence but exhibit almost no x-ray luminescence. However, intense x-ray luminescence from CdTe quantum dots is observed in LaF3:Ce/CdTe nanocomposites. This enhancement in the x-ray luminescence of CdTe quantum dots is attributed to the energy transfer from LaF3:Ce to CdTe quantum dots in the nanocomposites. The combination of LaF3:Ce nanoparticles and CdTe quantum dots makes LaF3:Ce/CdTe nanocomposites promising scintillators for radiation detection.
Global attractors for weighted p-Laplacian equations with boundary degeneracy
Authors: Ma Shan , Li Hongtao
Published: January 2012

Using a new a priori estimate method which is introduced by Zhong et al. [J. Differ. Equations 223(2), 367 (2006)]10.1016/j.jde.2005.06.008, we establish the existence of a global attractor in L2(Ω) and Lq(Ω)(q ⩾ 2), respectively, for weighted p-Laplacian equations with boundary degeneracy and without any restriction on the growing order of the nonlinearity.