bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors That Enhance English-Speaking Speech-Language Pathologists' Transcription of Cantonese-Speaking Children's Consonants
Authors: Lockart Rebekah , McLeod Sharynne
Published: July 2013

Purpose

To investigate speech-language pathology students' ability to identify errors and transcribe typical and atypical speech in Cantonese, a nonnative language.

Method

Thirty-three English-speaking speech-language pathology students completed 3 tasks in an experimental within-subjects design.

Results

Task 1 (baseline) involved transcribing English words. In Task 2, students transcribed 25 words spoken by a Cantonese adult. An average of 59.1% consonants was transcribed correctly (72.9% when Cantonese–English transfer patterns were allowed). There was higher accuracy on shared English and Cantonese syllable-initial consonants /m,n,f,s,h,j,w,l/ and syllable-final consonants. In Task 3, students identified consonant errors and transcribed 100 words spoken by Cantonese-speaking children under 4 additive conditions: (1) baseline, (2) +adult model, (3) +information about Cantonese phonology, and (4) all variables (2 and 3 were counterbalanced). There was a significant improvement in the students' identification and transcription scores for conditions 2, 3, and 4, with a moderate effect size. Increased skill was not based on listeners' proficiency in speaking another language, perceived transcription skill, musicality, or confidence with multilingual clients.

Conclusion

Speech-language pathology students, with no exposure to or specific training in Cantonese, have some skills to identify errors and transcribe Cantonese. Provision of a Cantonese-adult model and information about Cantonese phonology increased students' accuracy in transcribing Cantonese speech.
Lexical Diversity and Omission Errors as Predictors of Language Ability in the Narratives of Sequential Spanish–English Bilinguals: A Cross-Language Comparison
Authors: Jacobson Peggy F. , Walden Patrick R.
Published: July 2013

Purpose

This study explored the utility of language sample analysis for evaluating language ability in school-age Spanish–English sequential bilingual children. Specifically, the relative potential of lexical diversity and word/morpheme omission as predictors of typical or atypical language status was evaluated.

Method

Narrative samples were obtained from 48 bilingual children in both of their languages using the suggested narrative retell protocol and coding conventions as per Systematic Analysis of Language Transcripts (SALT; Miller & Iglesias, 2008) software. An additional lexical diversity measure, VocD, was also calculated. A series of logistical hierarchical regressions explored the utility of the number of different words, VocD statistic, and word and morpheme omissions in each language for predicting language status.

Results

Omission errors turned out to be the best predictors of bilingual language impairment at all ages, and this held true across languages. Although lexical diversity measures did not predict typical or atypical language status, the measures were significantly related to oral language proficiency in English and Spanish.

Conclusion

The results underscore the significance of omission errors in bilingual language impairment while simultaneously revealing the limitations of lexical diversity measures as indicators of impairment. The relationship between lexical diversity and oral language proficiency highlights the importance of considering relative language proficiency in bilingual assessment.
Nasalance Scores of Children With Repaired Cleft Palate Who Exhibit Normal Velopharyngeal Closure During Aerodynamic Testing
Authors: Zajac David J.
Published: July 2013

Purpose

To determine if children with repaired cleft palate and normal velopharyngeal (VP) closure as determined by aerodynamic testing exhibit greater acoustic nasalance than control children without cleft palate.

Method

Pressure-flow procedures were used to identify 2 groups of children based on VP closure during the production of /p/ in the word
hamper
: (a) children with repaired cleft palate and normal VP closure (
n
= 23) and (b) controls without cleft palate and with normal VP closure (
n
= 16). Acoustic nasalance scores were obtained for all children during the production of syllables with high-pressure consonants and sentences with low-pressure consonants (i.e., low-pressure sentences).

Results

Nasalance scores were generally higher for children with repaired cleft palate and normal VP function as compared to controls; however, a significant difference occurred only for low-pressure sentences (
p
= .005).

Conclusion

Results partially support a pressure-sensitive theory of VP function in that some children with repaired cleft palate may achieve VP closure during the production of high-pressure consonants but fail to do so during the production of vowels and low-pressure consonants. Clinical implications are discussed.
Order statistics inference for describing topological coupling and mechanical symmetry breaking in multidomain proteins
Authors: Kononova Olga , Jones Lee , Barsegov V.
Published: July 2013

Cooperativity is a hallmark of proteins, many of which show a modular architecture comprising discrete structural domains. Detecting and describing dynamic couplings between structural regions is difficult in view of the many-body nature of protein-protein interactions. By utilizing the GPU-based computational acceleration, we carried out simulations of the protein forced unfolding for the dimer WW − WW of the all-β-sheet WW domains used as a model multidomain protein. We found that while the physically non-interacting identical protein domains (WW) show nearly symmetric mechanical properties at low tension, reflected, e.g., in the similarity of their distributions of unfolding times, these properties become distinctly different when tension is increased. Moreover, the uncorrelated unfolding transitions at a low pulling force become increasingly more correlated (dependent) at higher forces. Hence, the applied force not only breaks “the mechanical symmetry” but also couples the physically non-interacting protein domains forming a multi-domain protein. We call this effect “the topological coupling.” We developed a new theory, inspired by order statistics, to characterize protein-protein interactions in multi-domain proteins. The method utilizes the squared-Gaussian model, but it can also be used in conjunction with other parametric models for the distribution of unfolding times. The formalism can be taken to the single-molecule experimental lab to probe mechanical cooperativity and domain communication in multi-domain proteins.
Electrostatic origin ofin vitroaggregation of human γ-crystallin
Authors: Mohr Benjamin G. , Dobson Cassidy M. , Garman Scott C. , Muthukumar Murugappan
Published: July 2013

The proteins α-, β-, and γ-crystallins are the major components of the lens in the human eye. Using dynamic light scattering method, we have performed in vitro investigations of protein-protein interactions in dilute solutions of human γ-crystallin and α-crystallin. We find that γ-crystallin spontaneously aggregates into finite-sized clusters in phosphate buffer solutions. There are two distinct populations of unaggregated and aggregated γ-crystallins in these solutions. On the other hand, α-crystallin molecules are not aggregated into large clusters in solutions of α-crystallin alone. When α-crystallin and γ-crystallin are mixed in phosphate buffer solutions, we demonstrate that the clusters of γ-crystallin are prevented. By further investigating the roles of temperature, protein concentration, pH, salt concentration, and a reducing agent, we show that the aggregation of γ-crystallin under our in vitro conditions arises from non-covalent electrostatic interactions. In addition, we show that aggregation of γ-crystallin occurs under the dilute in vitro conditions even in the absence of oxidizing agents that can induce disulfide cross-links, long considered to be responsible for human cataracts. Aggregation of γ-crystallin when maintained under reducing conditions suggests that oxidation does not contribute to the aggregation in dilute solutions.
Write operation study of Co/BTO/LSMO ferroelectric tunnel junction
Authors: Wang Z. H. , Zhao W. S. , Kang W. , Bouchenak-Khelladi A. , Zhang Y. , Klein J.-O. , Ravelosona D. , Chappert C.
Published: July 2013

Recently, a Co/BaTiO3/La0.67Sr0.33MnO3 (Co/BTO/LSMO) ferroelectric tunnel junction (FTJ) has shown the great potential towards non-volatile memory and logic applications due to its excellent performance. Especially, the giant OFF/ON tunnel resistance ratio (e.g., ∼100) assures that FTJ-based random access memory (FTRAM) can achieve lower reading error rate than emerging magnetic RAM. Nevertheless, in this paper, our investigation demonstrated that this FTJ suffered from difficulties in write operation when integrating with current CMOS technology into a FTRAM. Specifically, the write performances of Co/BTO/LSMO 1T1R FTRAM such as cell area, speed, energy dissipation, and thermal fluctuation effect were simulated and evaluated with a compact model and CMOS 40 nm design kit. Simulation results indicate the drawbacks of this FTRAM including significant performance asymmetry between two write orientations, high write voltage, large cell area, and severe thermal fluctuation disturbance. Simultaneously, this research provides several methods of improving write performance of FTRAM from the perspective of device size and process parameters.
First-principles thermodynamic screening approach to photo-catalytic water splitting with co-catalysts
Authors: Oberhofer Harald , Reuter Karsten
Published: July 2013

We adapt the computational hydrogen electrode approach to explicitly account for photo-generated charges and use it to computationally screen for viable catalyst/co-catalyst combinations for photo-catalytic water splitting. The hole energy necessary to thermodynamically drive the reaction is employed as descriptor for the screening process. Using this protocol and hybrid-level density-functional theory, we show that water oxidation on bare TiO2 surfaces is thermodynamically more complex than previously thought. This motivates a screening for suitable co-catalysts for this half-reaction, which we carry out for Au particles down to the non-scalable size regime. We find that almost all small Au clusters studied are better suited for water photo-oxidation than an extended Au(111) surface or bare TiO2 facets.
Proof of a conjecture by Gazeau et al. using the Gould-Hopper polynomials
Authors: Vignat C. , Lévêque O.
Published: July 2013

We provide here some probabilistic interpretations of the generalized binomial distributions proposed by Gazeau et al. [“Generating functions for generalized binomial distributions,” J. Math. Phys. 53, 103304 (2012)]10.1063/1.4757601. In the second part, we prove the “strong conjecture” expressed by Gazeau et al. about the coefficients of the Taylor expansion of the exponential of a polynomial. The proof relies mainly on properties of the Gould-Hopper polynomials.
Nonlinear theory of intense laser-plasma interactions modified by vacuum polarization effects
Authors: Chen Wenbo , Bu Zhigang , Li Hehe , Luo Yuee , Ji Peiyong
Published: July 2013

The classical nonlinear theory of laser-plasma interactions is corrected by taking account of the vacuum polarization effects. A set of wave equations are obtained by using the Heisenberg-Euler Lagrangian density and the derivative correction with the first-order quantum electrodynamic effects. A model more suitable to formulate the interactions of ultra-strong lasers and high-energy-density plasmas is developed. In the result, some environments in which the effects of vacuum polarization will be enhanced are discussed.
A large-area and contamination-free graphene transistor for liquid-gated sensing applications
Authors: Yu Wang Yung , Burke Peter J.
Published: July 2013

We present a simple, low-cost, large area, and contamination-free monolayer graphene field-effect transistor for liquid-gated sensing applications. The graphene surface does not require any photoresist including the commonly used polymethylmethacrylate, thus avoiding possible contamination and mobility degradation. We also examine the effects of different etching solutions and concentrations on the Dirac point of graphene. With optimal device fabrication recipe, we demonstrate the device's capability to sense different KCl concentrations and pH values under liquid gating configuration. Additionally, using polydimethylsiloxane as substrates holds an advantage of enabling simple integration between microfluidic systems and graphene for chemical and biological sensor applications.
Microfluidic platform for isolating nucleic acid targets using sequence specific hybridization
Authors: Wang Jingjing , Morabito Kenneth , Tang Jay X. , Tripathi Anubhav
Published: July 2013

The separation of target nucleic acid sequences from biological samples has emerged as a significant process in today's diagnostics and detection strategies. In addition to the possible clinical applications, the fundamental understanding of target and sequence specific hybridization on surface modified magnetic beads is of high value. In this paper, we describe a novel microfluidic platform that utilizes a mobile magnetic field in static microfluidic channels, where single stranded DNA (ssDNA) molecules are isolated via nucleic acid hybridization. We first established efficient isolation of biotinylated capture probe (BP) using streptavidin-coated magnetic beads. Subsequently, we investigated the hybridization of target ssDNA with BP bound to beads and explained these hybridization kinetics using a dual-species kinetic model. The number of hybridized target ssDNA molecules was determined to be about 6.5 times less than that of BP on the bead surface, due to steric hindrance effects. The hybridization of target ssDNA with non-complementary BP bound to bead was also examined, and non-specific hybridization was found to be insignificant. Finally, we demonstrated highly efficient capture and isolation of target ssDNA in the presence of non-target ssDNA, where as low as 1% target ssDNA can be detected from mixture. The microfluidic method described in this paper is significantly relevant and is broadly applicable, especially towards point-of-care biological diagnostic platforms that require binding and separation of known target biomolecules, such as RNA, ssDNA, or protein.
Heating of ions by high frequency electromagnetic waves in magnetized plasmas
Authors: Zestanakis P. A. , Kominis Y. , Hizanidis K. , Ram A. K.
Published: July 2013

The heating of ions by high frequency electrostatic waves in magnetically confined plasmas has been a paradigm for studying nonlinear wave-particle interactions. The frequency of the waves is assumed to be much higher than the ion cyclotron frequency and the waves are taken to propagate across the magnetic field. In fusion type plasmas, electrostatic waves, like the lower hybrid wave, cannot access the core of the plasma. That is a domain for high harmonic fast waves or electron cyclotron waves—these are primarily electromagnetic waves. Previous studies on heating of ions by two or more electrostatic waves are extended to two electromagnetic waves that propagate directly across the confining magnetic field. While the ratio of the frequency of each wave to the ion cyclotron frequency is large, the frequency difference is assumed to be near the ion cyclotron frequency. The nonlinear wave-particle interaction is studied analytically using a two time-scale canonical perturbation theory. The theory elucidates the effects of various parameters on the gain in energy by the ions—parameters such as the amplitudes and polarizations of the waves, the ratio of the wave frequencies to the cyclotron frequency, the difference in the frequency of the two waves, and the wave numbers associated with the waves. For example, the ratio of the phase velocity of the envelope formed by the two waves to the phase velocity of the carrier wave is important for energization of ions. For a positive ratio, the energy range is much larger than for a negative ratio. So waves like the lower hybrid waves will impart very little energy to ions. The theoretical results are found to be in good agreement with numerical simulations of the exact dynamical equations. The analytical results are used to construct mapping equations, simplifying the derivation of the motion of ions, which are, subsequently, used to follow the evolution of an ion distribution function. The heating of ions can then be properly quantified in terms of the wave parameters and can be conveniently used to find ideal conditions needed to heat ions by high frequency electromagnetic waves.
Graphene-metal contact resistivity on semi-insulating 6H-SiC(0001) measured with Kelvin probe force microscopy
Authors: Druga Thomas , Wenderoth Martin , Lüpke Felix , Ulbrich Rainer G.
Published: July 2013

We present Kelvin probe force microscopy measurements and resistance network simulations of the lateral charge transport across few-layer graphene on the semi-insulating 6H-SiC(0001) surface. After preparation of the SiC crystal by thermal decomposition, gold electrodes were prepared on the top of the graphene layers. The transport field is extracted by subtracting measurements of reverse lateral bias applied to the gold electrodes. Graphene sheet resistances as low as 0.75 kΩ/sq were observed. By comparing the experimental transport measurements with a resistance network simulation the contact resistivity between graphene and a gold electrode can be determined to be <1×10−6 Ω cm2.
Progressive multi-layer drop-casting of CdSe nanoparticles for photocurrent down shifing monitoring
Authors: Lambert Y. , Zhou Di , Xu Tao , Cristini O. , Deresmes D. , Grandidier B. , Stiévenard D.
Published: July 2013

We investigated the spectroscopic photocurrent response of photovoltaic devices versus an increasing number of drop-casted CdSe nanoparticles onto planar and nanocones silicon p-i-n junctions. For all samples, a strong enhancement of the photocurrent in the UV range was detected as well as a constant increase of the photocurrent up to 20% (16%) for a planar (nanocones) junction in the range 600–800 nm. The analysis of the photocurrent versus the number of drop casted nanoparticles layers allows us to evidence a down-shifting mechanism in the U-V range and an adaptative index effect below the threshold of absorption.
Fabrication of an InGaAs spin filter by implantation of paramagnetic centers
Authors: Nguyen C. T. , Balocchi A. , Lagarde D. , Zhang T. T. , Carrère H. , Mazzucato S. , Barate P. , Galopin E. , Gierak J. , Bourhis E , Harmand J. C. , Amand T. , Marie X.
Published: July 2013

We report on the selective creation of spin filtering regions in non-magnetic InGaAs layers by implantation of Ga ions by Focused Ion Beam. We demonstrate by photoluminescence spectroscopy that spin dependent recombination (SDR) ratios as high as 240% can be achieved in the implanted areas. The optimum implantation conditions for the most efficient SDR are determined by the systematic analysis of different ion doses spanning four orders of magnitude. The application of a weak external magnetic field leads to a sizable enhancement of the SDR ratio from the spin polarization of the nuclei surrounding the polarized implanted paramagnetic defects.
The Influence of Secondary Structure on Electron Transfer in Peptides
Authors: Yu Jingxian , Horsley John R. , Abell Andrew D.
Published: July 2013

A series of synthetic peptides containing 0–5 α-aminoisobutyric acid (Aib) residues and a C-terminal redox-active ferrocene was synthesised and their conformations defined by NMR and circular dichroism. Each peptide was separately attached to an electrode for subsequent electrochemical analysis in order to investigate the effect of peptide chain length (distance dependence) and secondary structure on the mechanism of intramolecular electron transfer. While the shorter peptides (0–2 residues) do not adopt a well defined secondary structure, the longer peptides (3–5 residues) adopt a helical conformation, with associated intramolecular hydrogen bonding. The electrochemical results on these peptides clearly revealed a transition in the mechanism of intramolecular electron transfer on transitioning from the ill-defined shorter peptides to the longer helical peptides. The helical structures undergo electron transfer via a hopping mechanism, while the shorter ill-defined structures proceeded via an electron superexchange mechanism. Computational studies on two β-peptides PCB-(β3Val-β3Ala-β3Leu)n–NHC(CH3)2OOtBu (n = 1 and 2; PCB = p-cyanobenzamide) were consistent with these observations, where the n = 2 peptide adopts a helical conformation and the n = 1 peptide an ill-defined structure. These combined studies suggest that the mechanism of electron transfer is defined by the extent of secondary structure, rather than merely chain length as is commonly accepted.
MicroRNA-regulated molecular mechanism underlying bovine subclinical endometritis
Authors: Hailemariam D. , Ibrahim S. , Hoelker M. , Drillich M. , Heuwieser W. , Looft C. , Cinar M. U. , Tholen E. , Schellander K. , Tesfaye D.
Published: July 2013

An impaired uterine environment triggered by the incidence of subclinical endometritis often compromises fertility in the bovine. The uterus is a dynamic organ with tight regulation of specific genes at the transcriptional and translational levels. Herein, we hypothesised that subclinical endometritis alters the expression of uterine microRNAs (miRNAs), which may result in the dysregulation of corresponding target genes and biological pathways. To test this hypothesis, we used a genome-wide RT2 (Exiqon, Vedbaek, Denmark) miRNA PCR array consisting of 354 miRNA primers and analysed miRNA expression in uterine cytobrush samples taken from cows with and without subclinical endometritis. The results revealed aberrant expression of 23 miRNAs in cows with subclinical endometritis compared with healthy cows. Furthermore, we designed an in vitro endometrial cell culture model challenged by lipopolysaccharide (LPS) to validate the differential regulation of miRNAs in cytobrush samples. Interestingly, we observed similar expression miRNA patterns in cytobrush samples taken from cows with or without subclinical endometritis and in vitro cultured endometrial cells challenged by LPS. To trace signalling pathways and biological functions potentially controlled by the aberrantly expressed miRNAs, we filtered high-ranking target genes from miRBase and analysed them using ingenuity pathway analysis. The gene networks, canonical pathways and biological functions strikingly converged to signalling pathways that mediate inflammatory responses, cellular proliferation, cell movement, the cell cycle and apoptosis in the bovine endometrium. In addition, expression analysis of key genes from the gene networks confirmed their presence and the potential regulation of these genes by uterine miRNAs. Furthermore, luciferase assay data substantiated the primary information from bioinformatic prediction that generated potential target genes for the dysregulated miRNAs in subclinical endometritis. Together, these data suggest the potential regulatory role of uterine miRNAs in the development and progression of bovine subclinical endometritis.
Microscale Environments along the Seaward Migration Route of Stocked Chum Salmon Fry
Authors: Hasegawa Koh , Takahashi Satoru
Published: July 2013

The microscale environment (e.g., current velocity) along the migratory route of aquatic organisms may directly affect their performance (e.g., migration speed or survival). We used minnow traps to evaluate how stocked Chum Salmon Oncorhynchus keta fry use stream velocity to optimize seaward migration. We found that fry were primarily captured at night and the number of fry collected was higher in traps with faster velocity water at the entrance to the trap. We interpreted this to mean that the fry were optimizing their migration efficiency by using faster velocity areas, which promote more rapid downstream migration.
Modification of Antimicrobial Prophylaxis Based on Rectal Culture Results to Prevent Fluoroquinolone-Resistant Escherichia coli Infections after Prostate Biopsy
Authors: Suwantarat Nuntra , Dumford Donald M. , Ponce-Terashima Rafael , Kundrapu Sirisha , Zabarsky Trina F. , Zhu Hui , Donskey Curtis J.
Published: July 2013

For patients undergoing transrectal ultrasound-guided biopsy of the prostate (TRUBP), use of rectal screening culture results to guide antimicrobial prophylaxis was effective for prevention of fluoro-quinolone-resistant Escherichia coli infections. In practice, elimination of infections after TRUBP required the rectal screening protocol and addition of gentamicin for patients missing prior screening.
Digital Anthropology
Authors: Boellstorff Tom , Dattatreyan Ethiraj Gabriel
Published: July 2013

Digital anthropology is an established and growing field focused on the Internet-related transformations that make possible a whole array of new social phenomena. Research in this exciting domain provides valuable perspectives regarding the relationship between digital communications technology and cultural practice, revealing new configurations of labor and capital, reinscriptions of hegemonic power, and novel experimentations with self-making and relationality. “Digital anthropology” is in conversation with other fields, including media anthropology, science and technology studies, sociology, art history, communications, design, media studies, and black studies. Digital anthropology, as such, is profoundly interdisciplinary. Indeed, many of the scholars cited here would not describe themselves as digital anthropologists, nor would they always be seen as such by others. This article is an updated version of Tom Boellstorff’s original article, published in 2013. The goal is to provide an examination of some key themes that broadly fall under the remit of digital anthropology. This version offers a “refresh” and slight remix of the sections that Boellstorff developed in the first version. Each section included in this bibliographic entry is not exhaustive. The listing of topics are heuristic and many of the cited works could have appeared under multiple headings. The citations included emphasize ethnographic research and relevant anthropological theory and, as such, the article does not include primarily quantitative, literary, historical, or philosophical scholarship. While early digital anthropological work focused on Euro-Western locations, more recent work has engaged with digital life, worlds, and cultural practices in the Global South and between geographic locations. This updated entry reflects this shift. In an era where “big data” can make quantitative methods appear to have a privileged vantage, digital anthropological research can offer simultaneously detailed and expansive studies with an attention to novel and consequential logics of digital communication technologies in relation to selfhood, power, and capital.
Under pressure: how a Mediterranean high‐mountain forb coordinates growth and hydraulic xylem anatomy in response to temperature and water constraints
Authors: Olano Jose Miguel , Almería Iván , Eugenio Màrcia , von Arx Georg
Published: July 2013

Plant growth in Mediterranean high mountains is limited by the double climatic stress of low winter temperatures and summer drought. Elevational shifts in response to climate change may be complex for species whose distribution is constrained by several climatic factors.

We used herb‐chronology, that is, the analysis of annual rings in the secondary root xylem of perennial forbs, to evaluate life‐long factors constraining secondary growth and xylem hydraulic anatomy along an elevational gradient from the upper to the lower distribution limits of the alpine forb Silene ciliata at its southernmost distribution range.

Generalized additive models (GAM) showed that annual ring width (RW) in S. ciliata was greatest at intermediate elevations and smallest at the upper and lower limits of its elevational range. In contrast, maximal vessel area (MVA) was greatest at lower elevations. RW responded to climatic conditions in early spring and late summer, suggesting the presence of a bimodal xylogenesis. Structural equation modelling (SEM) indicated a positive influence of MVA on RW in the same year; improved hydraulic efficiency seemed to promote higher secondary growth.

The observed greatest secondary growth (RW) and maximal vessel area (MVA) at intermediate and intermediate‐low elevations, respectively, contrasts with previous evidence of an improvement in plant reproduction and recruitment with increasing elevation for S. ciliata. However, our results are in agreement with other indicators suggesting that best conditions occur at intermediate elevations, such as better seed quality or larger genome size.

This study reinforces the evidence that the response of high‐mountain plants to climatic change under simultaneous temperature and drought stress is complex and that models that simply assume an increase in elevation as a response to higher temperatures may fail to predict future responses to climate change.
Numerical analysis of seismoelectric wave propagation in spatially confined geological units
Authors: Kröger Bernd , Yaramanci Ugur , Kemna Andreas
Published: July 2013

Using numerical modelling, we investigate the evolution of seismoelectric effects induced by seismic excitation in spatially confined lithological units. Typical geometries represent clay lenses embedded in an aquifer or petroleum deposits in a host rock. In fluid‐saturated rocks, seismic waves can generate electromagnetic fields due to electrokinetic coupling mechanisms associated with such processes in the vicinity of the fluid‐mineral interface. Two seismoelectric phenomena are investigated: (1) the co‐seismic field associated with the seismic displacement at each point in a subsurface and (2) the interface response generated at layer boundaries. Our modelling uses a simplified time‐domain formulation of the coupled problem and an efficient 2D finite‐element implementation. To gain insight into the morphogenetic field behaviour of the seismoelectric effects, several numerical simulations for various target geometries were treated. Accordingly, we varied both the thickness of the confined units and the value of the electrical bulk conductivity in porous media. Analysis of these effects shows differences between interface responses for electrically conductive versus resistive units. So the pertinent contrast in electrical bulk conductivity controls the shape and structure of these seismoelectric conversion patterns. Moreover, the seismoelectric interface response captures both the petrophysical and geometrical characteristics of the geological unit. These models demonstrate the value of using seismoelectric interface response for reservoir characterization in either hydrogeological or hydrocarbon exploration studies.
The evolution of the nutrient composition of mammalian milks
Authors: Skibiel Amy L. , Downing Lauren M. , Orr Teri J. , Hood Wendy R.
Published: July 2013

In mammals, nutrient allocation during lactation is a critical component of maternal care as milk intake promotes juvenile growth and survival, and hence maternal and offspring fitness.

Milk composition varies widely across mammals and is hypothesized to have arisen via selection pressures associated with environment, diet and life history. These hypotheses have been proposed based on observations and/or cross‐species comparisons that did not standardize for stage of lactation and did not consider evolutionary history of the species in analyses.

We conducted the largest comparative analysis of milk composition to date accounting for phylogenetic relationships among species in order to understand the selective advantage of producing milk with specific nutritional profiles. We examined four milk constituents in association with species ecology while incorporating phylogeny in analyses.

Phylogenetic signal was apparent for all milk constituents examined. After controlling for phylogeny, diet and relative lactation length explained the greatest amount of variation in milk composition. Several aspects of species' ecologies, including adaptation to arid environments, reproductive output and maternal body mass were not associated with milk composition after accounting for phylogeny.

Our results suggest that milk composition is largely a function of evolutionary history, maternal nutrient intake and duration of milk production. Arriving at these conclusions was made possible by including the evolutionary relationships among species.
Snake co‐occurrence patterns are best explained by habitat and hypothesized effects of interspecific interactions
Authors: Steen David A. , McClure Christopher J. W. , Brock Jean C. , Craig Rudolph D. , Pierce Josh B. , Lee James R. , Jeffrey Humphries W. , Gregory Beau B. , Sutton William B. , Smith Lora L. , Baxley Danna L. , Stevenson Dirk J. , Guyer Craig
Published: July 2013

Snakes often occur in species‐rich assemblages, and sympatry is thought to be facilitated primarily by low diet overlap, not interspecific interactions.

We selected, a priori, three species pairs consisting of species that are morphologically and taxonomically similar and may therefore be likely to engage in interspecific, consumptive competition. We then examined a large‐scale database of snake detection/nondetection data and used occupancy modelling to determine whether these species occur together more or less frequently than expected by chance while accounting for variation in detection probability among species and incorporating important habitat categories in the models.

For some snakes, we obtained evidence that the probabilities that habitat patches are used are influenced by the presence of potentially competing congeneric species. Specifically, timber rattlesnakes (Crotalus horridus) were less likely than expected by chance to use areas that also contained eastern diamond‐backed rattlesnakes (Crotalus adamanteus) when the proportion of evergreen forest was relatively high. Otherwise, they occurred together more often than expected by chance. Complex relationships were revealed between habitat use, detection probabilities and occupancy probabilities of North American racers (Coluber constrictor) and coachwhips (Coluber flagellum) that indicated the probability of competitive exclusion increased with increasing area of grassland habitat, although there was some model uncertainty. Cornsnakes (Pantherophis guttatus or Pantherophis slowinskii) and ratsnakes (Pantherophis alleghaniensis, Pantherophis spiloides, or Pantherophis obsoletus) exhibited differences in habitat selection, but we obtained no evidence that patterns of use for this species pair were influenced by current interspecific interactions.

Overall, our results are consistent with the hypothesis that competitive interactions influence snake assemblage composition; the strength of these effects was affected by landscape‐scale habitat features. Furthermore, we suggest that current interspecific interactions may influence snake occupancy, challenging the paradigm that contemporary patterns of snake co‐occurrence are largely a function of diet partitioning that arose over evolutionary time.
Trophic cascades from wolves to grizzly bears in Yellowstone
Authors: Ripple William J. , Beschta Robert L. , Fortin Jennifer K. , Robbins Charles T.
Published: July 2013

We explored multiple linkages among grey wolves (Canis lupus), elk (Cervus elaphus), berry‐producing shrubs and grizzly bears (Ursus arctos) in Yellowstone National Park.

We hypothesized competition between elk and grizzly bears whereby, in the absence of wolves, increases in elk numbers would increase browsing on berry‐producing shrubs and decrease fruit availability to grizzly bears. After wolves were reintroduced and with a reduced elk population, we hypothesized there would be an increase in the establishment of berry‐producing shrubs, such as serviceberry (Amelanchier alnifolia), which is a major berry‐producing plant. We also hypothesized that the percentage fruit in the grizzly bear diet would be greater after than before wolf reintroduction.

We compared the frequency of fruit in grizzly bear scats to elk densities prior to wolf reintroduction during a time of increasing elk densities (1968–1987). For a period after wolf reintroduction, we calculated the percentage fruit in grizzly bear scat by month based on scats collected in 2007–2009 (n = 778 scats) and compared these results to scat data collected before wolf reintroduction. Additionally, we developed an age structure for serviceberry showing the origination year of stems in a northern range study area.

We found that over a 19‐year period, the percentage frequency of fruit in the grizzly diet (6231 scats) was inversely correlated (P < 0·001) with elk population size. The average percentage fruit in grizzly bear scats was higher after wolf reintroduction in July (0·3% vs. 5·9%) and August (7·8% vs. 14·6%) than before. All measured serviceberry stems accessible to ungulates originated since wolf reintroduction, while protected serviceberry growing in a nearby ungulate exclosure originated both before and after wolf reintroduction. Moreover, in recent years, browsing of serviceberry outside of the exclosure decreased while their heights increased.

Overall, these results are consistent with a trophic cascade involving increased predation by wolves and other large carnivores on elk, a reduced and redistributed elk population, decreased herbivory and increased production of plant‐based foods that may aid threatened grizzly bears.
Does Coordination of Welfare Services Delivery Make a Difference for Extremely Disadvantaged Jobseekers? Evidence from the ‘YP4’ Trial
Authors: Borland Jeff , Tseng Yi‐Ping , Wilkins Roger
Published: July 2013

Fragmented welfare service delivery has been identified as a significant barrier to improving outcomes for highly disadvantaged populations. The YP4 trial, conducted from 2005 to 2009, sought to evaluate, by randomised control method, an approach proposed by Campbell et al. (2003) for integrating delivery of employment, housing, health and other services for young homeless jobseekers. Rather than providing extra access to services or utilisation of different services, the YP4 trial involved assignment of a case manager to tailor and coordinate available services to reflect the specific circumstances of young homeless jobseekers. We find that the YP4 program did not have a significant effect on economic or psychological well‐being, a finding that is robust to application of experimental and quasi‐experimental methods. It is argued that our study contributes to knowledge on programme design, particularly in relation to the importance of the scale of intervention and programme administration.
Sevoflurane causes neuronal apoptosis and adaptability changes of neonatal rats
Authors: ZHENG S. Q. , AN L. X. , CHENG X. , WANG Y. J.
Published: July 2013

Background

Neonatal exposure to sevoflurane can induce neurodegeneration and learning deficits in developing brain. We hypothesised that with the increase in the concentration and duration of sevoflurane, neurodegeneration of neonatal rats aggravates and causes behaviour changes as the rats grow.

Methods

Twenty‐one post‐natal day (P)7 Wistar rats were randomly divided into seven groups. Blood analysis was performed after anaesthesia. According to the results, 120 P7 Wistar rats were randomly divided into five groups: Con sham anaesthesia; Sevo 1%‐2 h: exposed to 1% sevoflurane for 2 h; Sevo 1%‐4 h, Sevo 2%‐2 h and Sevo 2%‐4 h. Caspase‐3 positive cells in brain were detected by immunohistochemistry at 6 h after the end of anaesthesia. The cleaved poly(ADP‐ribose) polymerase (c‐PARP‐1) in cortex and hippocampus was detected by Western blot analysis. Behavioural tests such as Morris water maze and Open‐field Test were performed when the rats were 5‐week old, 8‐week old, and 14‐week old.

Results

Three per cent sevoflurane induced carbon dioxide accumulation. The level of c‐PARP‐1 in hippocampus area was significantly increased in Group 2%‐4h. The number of caspase‐3 positive cells in Group Sevo 1%‐2h, Group Sevo 2%‐2h and Group Sevo 2%‐4h was greater than that in Group Con. Rats exposed to sevoflurane had longer travel distance and time in open field when they were 5 weeks old. Animals from different groups had similar performance in Morris water maze.

Conclusion

Exposure to 2% sevoflurane causes neuronal apoptosis of neonatal rats, and long‐time exposure aggravates that. The adaptability in new environment is transiently decreased when the anaesthesia rats are 5 weeks old.
Novel interactions between mitochondrial superoxide dismutases and the electron transport chain
Authors: Suthammarak Wichit , Somerlot Benjamin H. , Opheim Elyce , Sedensky Margaret , Morgan Philip G.
Published: July 2013

The processes that control aging remain poorly understood. We have exploited mutants in the nematode, Caenorhabditis elegans, that compromise mitochondrial function and scavenging of reactive oxygen species (ROS) to understand their relation to lifespan. We discovered unanticipated roles and interactions of the mitochondrial superoxide dismutases (mtSODs): SOD‐2 and SOD‐3. Both SODs localize to mitochondrial supercomplex I:III:IV. Loss of SOD‐2 specifically (i) decreases the activities of complexes I and II, complexes III and IV remain normal; (ii) increases the lifespan of animals with a complex I defect, but not the lifespan of animals with a complex II defect, and kills an animal with a complex III defect; (iii) induces a presumed pro‐inflammatory response. Knockdown of a molecule that may be a pro‐inflammatory mediator very markedly extends lifespan and health of certain mitochondrial mutants. The relationship between the electron transport chain, ROS, and lifespan is complex, and defects in mitochondrial function have specific interactions with ROS scavenging mechanisms. We conclude that mtSODs are embedded within the supercomplex I:III:IV and stabilize or locally protect it from reactive oxygen species (ROS) damage. The results call for a change in the usual paradigm for the interaction of electron transport chain function, ROS release, scavenging, and compensatory responses.
Ecophysiological and species‐specific responses to seasonal variations in halophytic species of the chenopodiaceae in a Mediterranean salt marsh
Authors: Barakat Nasser A. M. , Cazzato Eugenio , Nedjimi Bouzid , Kabiel Hanan F. , Laudadio Vito , Tufarelli Vincenzo
Published: July 2013

Plants adopt different strategies in response to seasonal variations in their natural biotype. In this study, the responses of seasonal changes on the organic osmolyte contents, ionic homoeostasis, osmotic potential and succulence of native chenopods in a salt marsh of Egypt were studied. Five halophytic species of the chenopodiaceae were collected during the rainy and dry season: Atriplex halimus L., Halocnemum strobilaceum (Pall.), Salicornia fruticosa (L.), Suaeda pruinosa (Lange) and Arthrocnemum macrostachyum (Moric). Results showed that plants employ an osmoconformer strategy via species specificity of response to seasonal variations. The total ions accumulation in all species was higher during the rainy season compared with the dry season. In particular, during rainy season, A. halimus resulted the higher accumulator species, followed by H. strobilaceum. Conversely, S. fruticosa, S. pruinosa and A. macrostachyum were defined as low‐accumulator species. In each studied species, the effective salinity, biological absorption coefficient as well as leaf succulence were higher during the rainy season. In conclusion, the present study have pointed out the importance that should be accorded with the development of research directed towards agronomic aspects for the uses of halophytic chenopodiaceae in salt marsh. Further, data obtained indicate that the ions accumulator species should be considered for use in phytoremediation of degraded saline lands.
Diffuse opacities in 12‐year‐old Hong Kong children – four cross‐sectional surveys
Authors: Wong Hai Ming , McGrath Colman , King Nigel M.
Published: July 2013

Objectives

To compare the prevalence and severity of diffuse opacities among subjects whose maxillary incisors developed during periods with different concentrations of fluoride in the Hong Kong public water supply.

Methods

Standardized intra‐oral photographs of random samples of 12‐year‐old children were collected in 1983, 1991, 2001 and 2010 (n = 2658) in Hong Kong and were assessed for diffuse opacities by a calibrated and blinded examiner. The fluoride concentrations in the public water supply at the times when the enamel on their maxillary incisors developed were 1.0, 0.7, 0.5 and 0.5 ppm, respectively.

Results

The mouth prevalence figures for diffuse opacities of these children (based on the maxillary incisors) were 89.3%, 48.5%, 32.4% and 42.1 in the years 1983, 1991, 2001 and 2010, respectively. Variation in the mouth and tooth prevalences of diffuse opacities was apparent among the four different year groups (P < 0.0001). Marked differences in severity of diffuse opacities, in terms of different subtypes and maximum extent of tooth affected, were also observed in association with the year of study (P < 0.001).

Conclusions

The prevalence and severity of diffuse opacities among maxillary incisor teeth of Hong Kong children decreased from 1983 and then increased in 2010; however, this change did not fully correspond to the concentration of fluoride in the drinking water during the time of enamel development.
Anxiety and depression seem less common in patients with autoreactive chronic spontaneous urticaria
Authors: Weller K. , Koti I. , Makris M. , Maurer M.
Published: July 2013

Chronic spontaneous urticaria (CSU) is a common and disabling skin disease which is often associated with psychiatric comorbidities such as anxiety and depression. These conditions are widely thought to cause, drive and/or maintain CSU, and have been reported as making an important contribution to the low quality of life in patients with CSU. Almost half of all patients with CSU have autoreactive CSU which can be readily diagnosed by the autologous serum skin test. The prevalence and effects of psychiatric comorbidities in this important subgroup are largely unknown. We carried out a study on two groups of patients with CSU, and found that the anxiety and depression scores were lower in patients with autoreactive CSU than in those with nonautoreactive CSU, the first such finding, to our knowledge. In addition, we found that patients with autoreactive CSU were less likely to have Hospital Anxiety and Depression Scale scores indicative for anxiety or depression compared with patients with nonautoreactive CSU. Our results support the view that autoreactive CSU represents a distinct CSU subgroup with a different disease pattern and a lower rate of psychiatric comorbidities.