bluuebunny/crossref_metadata_2025 huggingface dataset:
Existence and non-existence of solutions to elliptic equations with a general convection term
Authors: Alarcón Salomón , García-Melián Jorge , Quaas Alexander
Published: March 2014

In this paper we consider the nonlinear elliptic problem −Δu + αu = g(∣∇u∣) + λh(x) in Ω, u = 0 on ∂Ω, where Ω is a smooth bounded domain of ℝN, α ≥ 0, g is an arbitrary C1 increasing function and h ∈ C1() is non-negative. We completely analyse the existence and non-existence of (positive) classical solutions in terms of the parameter λ. We show that there exist solutions for every λ when α = 0 and the integral 1/g(s)ds = ∞, or when α > 0 and the integral s/g(s)ds = ∞. Conversely, when the respective integrals converge and h is non-trivial on ∂Ω, existence depends on the size of λ. Moreover, non-existence holds for large λ. Our proofs mainly rely on comparison arguments, and on the construction of suitable supersolutions in annuli. Our results include some cases where the function g is superquadratic and existence still holds without assuming any smallness condition on λ.
Existence and multiplicity of solutions of Schrödinger—Poisson systems with radial potentials
Authors: Li Anran , Su Jiabao , Zhao Leiga
Published: March 2014

In this paper, we deal with the nonlinear Schrödinger–Poisson system

where λ > 0, V and Q are radial functions, which can be vanishing or coercive at ∞. With assumptions on f just in a neighbourhood of the origin, existence and multiplicity of non-trivial radial solutions are obtained via variational methods. In particular, if f is sublinear and odd near the origin, we obtain infinitely many solutions of (SP)λ for any λ < 0.
On the Allen—Cahn/Cahn—Hilliard system with a geometrically linear elastic energy
Authors: Blesgen Thomas , Schlömerkemper Anja
Published: March 2014

We present an extension of the Allen-Cahn/Cahn-Hilliard system that incorporates a geometrically linear ansatz for the elastic energy of the precipitates. The model contains both the elastic Allen-Cahn system and the elastic Cahn-Hilliard system as special cases, and accounts for the microstructures on the microscopic scale. We prove the existence of weak solutions to the new model for a general class of energy functionals. We then give several examples of functionals that belong to this class. This includes the energy of geometrically linear elastic materials for dimensions D < 3. Moreover, we show this for D = 3 in the setting of scalar-valued deformations, which corresponds to the case of anti-plane shear. All this is based on explicit formulae for relaxed energy functionals newly derived in this article for D = 1 and D = 3. In these cases we can also prove the uniqueness of the weak solutions.
Preclinical Alzheimer's disease
Authors: Gil-Gregorio P , Yubero-Pancorbo R
Published: March 2014

Recently, diagnostic criteria for preclinical Alzheimer's disease have been proposed. These describe and define three stages of disease. Stage I is focused on asymptomatic cerebral amyloidosis. Stage II includes evidence of synaptic dysfunction and/or early degeneration. Finally, stage III of the disease is characterized by the beginning of cognitive decline.
High-fidelity Human Patient Simulators Compared with Human Actors in an Unannounced Mass-Casualty Exercise
Authors: Schulz Christian M. , Skrzypczak Matthias , Raith Stefan , Hinzmann Dominik , Krautheim Veronika , Heuser Fabian , Mayer Valentin , Kreuzer Christoph , Himsl Meike , Holl Michael , Lipp Christina , Kochs Eberhard F. , Wagner Klaus J.
Published: March 2014

High-fidelity simulators (HFSs) have been shown to prompt critical actions at a level equal to that of trained human actors (HAs) and increase perceived realism in intrahospital mass-casualty incident (MCI) exercises. For unannounced prehospital MCI exercises, however, no data are available about the feasibility of incorporating HFSs. This case report describes the integration of HFSs in such an unannounced prehospital MCI drill with HAs and provides data about the differences concerning triage, treatment, and transport of HFSs and HAs with identical injury patterns. For this purpose, 75 actors and four high-fidelity simulators were subdivided into nine groups defined by a specific injury pattern. Four HFSs and six HAs comprised a group suffering from traumatic brain injury and blunt abdominal trauma. Triage results, times for transport, and number of diagnostic and therapeutic tasks were recorded. Means were compared by t test or one-way ANOVA.

Triage times and results did not differ between actors and simulators. The number of diagnostic (1.25, SD = 0.5 in simulators vs 3.5, SD = 1.05 in HAs; P = .010) and therapeutic tasks (2.0, SD = 1.6 in simulators vs 4.8, SD = 0.4 in HAs; P = .019) were significantly lower in simulators. Due to difficulties in treating and evacuating the casualties from the site of the accident in a timely manner, all simulators died. Possible causal factors and strategies are discussed, with the aim of increasing the utility of simulators in emergency medicine training.

SchulzCM, SkrzypczakM, RaithS, HinzmannD, KrautheimV, HeuserF, MayerV, KreuzerC, HimslM, HollM, LippC, KochsEF, WagnerKJ. High-fidelity human patient simulators compared with human actors in an unannounced mass-casualty exercise. Prehosp Disaster Med. 2014;29(2):1-7.
Christian America? Understanding the Link between Churches, Attitudes, and “Being American” among Latino Immigrants
Authors: Taylor J. Benjamin , Gershon Sarah Allen , Pantoja Adrian D.
Published: March 2014

In recent decades, Evangelical churches in the United States have expanded their outreach to Latino immigrants, seeking to incorporate these new Americans into their churches. We investigate the implications of this movement by examining the impact of church affiliation on Latino immigrants’ conceptions of what it means to be “fully American.” Relying on the 2006 Latino National Survey, we find that church affiliation significantly impacts immigrants’ beliefs about what it means to “be American” in the eyes of other Americans and the likelihood of identifying themselves as “American.” Specifically, Protestant Latinos (be they mainline or Evangelical) are more likely than Catholic Latinos (the majority of Latinos) to identify as American and to believe that Americans think being a Christian is a defining feature of American identity. We conclude by discussing the implications of our findings.
Overcoming inherent resistance to histone deacetylase inhibitors in multiple myeloma cells by targeting pathways integral to the actin cytoskeleton
Authors: Mithraprabhu S , Khong T , Spencer A
Published: March 2014

Histone deacetylase inhibitors (HDACi) are novel chemotherapeutics undergoing evaluation in clinical trials for the potential treatment of patients with multiple myeloma (MM). Although HDACi have demonstrable synergy when combined with proteasome inhibitors (PIs), recent evidence indicates that combination of HDACi and PI is beneficial only in a subset of patients with advanced MM, clearly indicating that other rational combinations should be explored. In this context we hypothesized that understanding the molecular signature associated with inherent resistance to HDACi would provide a basis for the identification of therapeutic combinations with improved clinical efficacy. Using human myeloma cell lines (HMCL) categorized as sensitive, intermediate or resistant to HDACi, gene expression profiling (GEP) and gene ontology enrichment analyses were performed to determine if a genetic signature associated with inherent resistance to HDACi-resistance could be identified. Correlation of GEP to increasing or decreasing sensitivity to HDACi indicated a unique 35-gene signature that was significantly enriched for two pathways – regulation of actin cytoskeleton and protein processing in endoplasmic reticulum. When HMCL and primary MM samples were treated with a combination of HDACi and agents targeting the signaling pathways integral to the actin cytoskeleton, synergistic cell death was observed in all instances, thus providing a rationale for combining these agents with HDACi for the treatment of MM to overcome resistance. This report validates a molecular approach for the identification of HDACi partner drugs and provides an experimental framework for the identification of novel therapeutic combinations for anti-MM treatment.
Predictive modeling of gingivitis severity and susceptibility via oral microbiota
Authors: Huang Shi , Li Rui , Zeng Xiaowei , He Tao , Zhao Helen , Chang Alice , Bo Cunpei , Chen Jie , Yang Fang , Knight Rob , Liu Jiquan , Davis Catherine , Xu Jian
Published: March 2014

Predictive modeling of human disease based on the microbiota holds great potential yet remains challenging. Here, 50 adults underwent controlled transitions from naturally occurring gingivitis, to healthy gingivae (baseline), and to experimental gingivitis (EG). In diseased plaque microbiota, 27 bacterial genera changed in relative abundance and functional genes including 33 flagellar biosynthesis-related groups were enriched. Plaque microbiota structure exhibited a continuous gradient along the first principal component, reflecting transition from healthy to diseased states, which correlated with Mazza Gingival Index. We identified two host types with distinct gingivitis sensitivity. Our proposed microbial indices of gingivitis classified host types with 74% reliability, and, when tested on another 41-member cohort, distinguished healthy from diseased individuals with 95% accuracy. Furthermore, the state of the microbiota in naturally occurring gingivitis predicted the microbiota state and severity of subsequent EG (but not the state of the microbiota during the healthy baseline period). Because the effect of disease is greater than interpersonal variation in plaque, in contrast to the gut, plaque microbiota may provide advantages in predictive modeling of oral diseases.
Micro/nano Fabrication Technologies for Vibration-Based Energy Harvester
Authors: Yang Bin , Liu Jingquan
Published: March 2014

Energy harvesting technologies have emerged as a prominent research topic and been quickly developed in recent years due to its wide application, such as wireless sensor nodes for structural health monitoring, biomedical applications for implanted sensors, and automobile applications for tire pressure sensors. Recent development focuses on the novel material, structural optimized design, process integration of micro to nanoscale energy harvesters. This chapter demonstrates the micromachining technologies for the fabrication of micro/nanoscale energy harvesters.
Challenges in modelling homogeneous catalysis: new answers from ab initio molecular dynamics to the controversy over the Wacker process
Authors: Stirling András , Nair Nisanth N. , Lledós Agustí , Ujaque Gregori
Published: March 2014

The controversial reaction mechanism considering experimental results and theoretical treatment from static to ab initio molecular dynamic simulations is reviewed.
On the upconversion fluorescence in carbon nanodots and graphene quantum dots
Authors: Wen Xiaoming , Yu Pyng , Toh Yon-Rui , Ma Xiaoqian , Tang Jau
Published: March 2014

So-called upconversion fluorescence in CNDs and GQDs is confirmed originating from a measurement mistake; therefore cross-check is very necessary.
High-resolution adsorption analysis of pillared zeolites IPC-3PI and MCM-36
Authors: Zukal Arnošt , Kubů Martin
Published: March 2014

The porous structure of pillared zeolites IPC-3PI and MCM-36 depends, in the lower mesopore region, on the stacking of MWW layers.
Microfluidics for electronic paper-like displays
Authors: Shui Lingling , Hayes Robert A. , Jin Mingliang , Zhang Xiao , Bai Pengfei , van den Berg Albert , Zhou Guofu
Published: March 2014

Displays are ubiquitous in modern life, and there is a growing need to develop active, full color, video-rate reflective displays that perform well in high-light conditions.
Elevating sampling
Authors: Labuz Joseph M. , Takayama Shuichi
Published: March 2014

This perspective highlights challenges and opportunities in the collection and preparation of a target from real-world sources for subsequent processing in micro- and nanofluidic systems.
Combining a wavelet change point and the Bayes factor for analysing chromosomal interaction data
Authors: Shavit Yoli , Lio' Pietro
Published: March 2014

We provide a step-by-step statistical bioinformatics solution to the analysis of chromosomal interaction data. To the best of our knowledge, there is currently no available methodology for following this entire pipeline.
In vitrotoxicological characterisation of three arsenic-containing hydrocarbons
Authors: Meyer S. , Matissek M. , Müller S. M. , Taleshi M. S. , Ebert F. , Francesconi K. A. , Schwerdtle T.
Published: March 2014

Arsenic-containing hydrocarbons exert strong toxic effects in cultured human cells.
The hybrid concept for realization of an ultra-thin plasmonic metamaterial antireflection coating and plasmonic rainbow
Authors: Hedayati M. Keshavarz , Fahr S. , Etrich C. , Faupel F. , Rockstuhl C. , Elbahri M.
Published: March 2014

We develop a plasmonic broadband anti-reflector based on a tunable metamaterial which could potentially act as a plasmonic rainbow.
Selective colorimetric and ratiometric probe for Ni(ii) in quinoxaline matrix with the single crystal X-ray structure
Authors: Goswami Shyamaprosad , Chakraborty Shampa , Das Avijit Kumar , Manna Abhishek , Bhattacharyya Aditya , Quah Ching Kheng , Fun Hoong-Kun
Published: March 2014

A quinoxaline based colorimetric nickel sensor,HQAP[2-(quinoxalin-2-ylmethyleneamine)phenol] with high selectivity and sensitivity toward Ni2+ions is shown to have potential for practical use.
A novel damage-tolerant superhydrophobic and superoleophilic material
Authors: Zhang Xia , Guo Yonggang , Chen Hengzhen , Zhu Wenzhong , Zhang Pingyu
Published: March 2014

A novel damage-tolerant bulk material with superhydrophobic and superoleophilic properties is fabricated by a facile method.
Protein folding, structure prediction and design
Authors: Baker David
Published: March 2014

I describe how experimental studies of protein folding have led to advances in protein structure prediction and protein design. I describe the finding that protein sequences are not optimized for rapid folding, the contact order–protein folding rate correlation, the incorporation of experimental insights into protein folding into the Rosetta protein structure production methodology and the use of this methodology to determine structures from sparse experimental data. I then describe the inverse problem (protein design) and give an overview of recent work on designing proteins with new structures and functions. I also describe the contributions of the general public to these efforts through the Rosetta@home distributed computing project and the FoldIt interactive protein folding and design game.
HDAC inhibitors as cognitive enhancers in fear, anxiety and trauma therapy: where do we stand?
Authors: Whittle Nigel , Singewald Nicolas
Published: March 2014

A novel strategy to treat anxiety and fear-related disorders such as phobias, panic and PTSD (post-traumatic stress disorder) is combining CBT (cognitive behavioural therapy), including extinction-based exposure therapy, with cognitive enhancers. By targeting and boosting mechanisms underlying learning, drug development in this field aims at designing CBT-augmenting compounds that help to overcome extinction learning deficits, promote long-term fear inhibition and thus support relapse prevention. Progress in revealing the role of epigenetic regulation of specific genes associated with extinction memory generation has opened new avenues in this direction. The present review examines recent evidence from pre-clinical studies showing that increasing histone acetylation, either via genetic or pharmacological inhibition of HDACs (histone deacetylases) by e.g. vorinostat/SAHA (suberoylanilide hydroxamic acid), entinostat/MS-275, sodium butyrate, TSA (trichostatin A) or VPA (valproic acid), or by targeting HATs (histone acetyltransferases), augments fear extinction and, importantly, generates a long-term extinction memory that can protect from return of fear phenomena. The molecular mechanisms and pathways involved including BDNF (brain-derived neurotrophic factor) and NMDA (N-methyl-D-aspartate) receptor signalling are just beginning to be revealed. First studies in healthy humans are in support of extinction-facilitating effects of HDAC inhibitors. Very recent evidence that HDAC inhibitors can rescue deficits in extinction-memory-impaired rodents indicates a potential clinical utility of this approach also for exposure therapy-resistant patients. Important future work includes investigation of the long-term safety aspects of HDAC inhibitor treatment, as well as design of isotype(s)-specific inhibitors. Taken together, HDAC inhibitors display promising potential as pharmacological adjuncts to augment the efficacy of exposure-based approaches in anxiety and trauma therapy.
Phosphoproteomic studies inArabidopsisand tobacco male gametophytes
Authors: Fíla Jan , Čapková Věra , Honys David
Published: March 2014

Mature pollen represents an extremely resistant quiescent structure surrounded by a tough cell wall. After its hydration on stigma papillary cells, pollen tube growth starts rapidly. Massive metabolic changes are likely to be accompanied by changes in protein phosphorylation. Protein phosphorylation belongs among the most rapid post-translational modifications. To date, only Arabidopsis thaliana and tobacco (Nicotiana tabacum) mature pollen have been subjected to phosphoproteomic studies in order to identify the phosphoproteins present. In the present mini-review, Arabidopsis and tobacco datasets were compared with each other. The representation of the O-phosphorylated amino acids was compared between these two datasets, and the putative pollen-specific or pollen-abundant phosphopeptides were highlighted. Finally, the phosphorylation sites common for both Arabidopsis and tobacco phosphoproteins are listed as well as the phosphorylation motifs identified.
Identifying plant cell-surface receptors: combining ‘classical’ techniques with novel methods
Authors: Uebler Susanne , Dresselhaus Thomas
Published: March 2014

Cell–cell communication during development and reproduction in plants depends largely on a few phytohormones and many diverse classes of polymorphic secreted peptides. The peptide ligands are bound at the cell surface of target cells by their membranous interaction partners representing, in most cases, either receptor-like kinases or ion channels. Although knowledge of both the extracellular ligand and its corresponding receptor(s) is necessary to describe the downstream signalling pathway(s), to date only a few ligand–receptor pairs have been identified. Several methods, such as affinity purification and yeast two-hybrid screens, have been used very successfully to elucidate interactions between soluble proteins, but most of these methods cannot be applied to membranous proteins. Experimental obstacles such as low concentration and poor solubility of membrane receptors, as well as instable transient interactions, often hamper the use of these ‘classical’ approaches. However, over the last few years, a lot of progress has been made to overcome these problems by combining classical techniques with new methodologies. In the present article, we review the most promising recent methods in identifying cell-surface receptor interactions, with an emphasis on success stories outside the field of plant research.
Evolutionarily conserved mechanisms of male germline development in flowering plants and animals
Authors: Pereira Patrícia A. , Navarro-Costa Paulo , Martinho Rui Gonçalo , Becker Jörg D.
Published: March 2014

Sexual reproduction is the main reproductive strategy of the overwhelming majority of eukaryotes. This suggests that the last eukaryotic common ancestor was able to reproduce sexually. Sexual reproduction reflects the ability to perform meiosis, and ultimately generating gametes, which are cells that carry recombined half sets of the parental genome and are able to fertilize. These functions have been allocated to a highly specialized cell lineage: the germline. Given its significant evolutionary conservation, it is to be expected that the germline programme shares common molecular bases across extremely divergent eukaryotic species. In the present review, we aim to identify the unifying principles of male germline establishment and development by comparing two very disparate kingdoms: plants and animals. We argue that male meiosis defines two temporally regulated gene expression programmes: the first is required for meiotic commitment, and the second is required for the acquisition of fertilizing ability. Small RNA pathways are a further key communality, ultimately ensuring the epigenetic stability of the information conveyed by the male germline.
Reactive metabolites as a cause of late diabetic complications
Authors: Fleming Thomas , Nawroth Peter P.
Published: March 2014

Patients suffering from DN (diabetic neuropathy) suffer from the coexistence of positive (i.e. pain, hypersensitivity, tingling, cramps, cold feet, etc.) and negative (i.e. loss of sensory perception, delayed wound healing, etc.) symptoms. Elevated blood glucose alone cannot explain the development and progression of DN. Recently it has been shown that the endogenous reactive metabolite MG (methylglyoxal), elevated as a consequence of reduced Glo1 (glyoxalase I), can contribute to the gain of function via post-translational modification of neuronal ion channels involved in chemosensing and action potential generation in nociceptive nerve endings. The effects of dicarbonyls on the neuronal compartment provides a unifying mechanism for the development of DN. Targeting the accumulation and effects of MG may therefore provide new, more effective, therapeutic approaches for the treatment of DN.
Why don't plants have diabetes? Systems for scavenging reactive carbonyls in photosynthetic organisms
Authors: Shimakawa Ginga , Suzuki Mayumi , Yamamoto Eriko , Saito Ryota , Iwamoto Tatsuya , Nishi Akiko , Miyake Chikahiro
Published: March 2014

In the present paper, we review the toxicity of sugar- and lipid-derived RCs (reactive carbonyls) and the RC-scavenging systems observed in photosynthetic organisms. Similar to heterotrophs, photosynthetic organisms are exposed to the danger of RCs produced in sugar metabolism during both respiration and photosynthesis. RCs such as methylglyoxal and acrolein have toxic effects on the photosynthetic activity of higher plants and cyanobacteria. These toxic effects are assumed to occur uniquely in photosynthetic organisms, suggesting that RC-scavenging systems are essential for their survival. The aldo–keto reductase and the glyoxalase systems mainly scavenge sugar-derived RCs in higher plants and cyanobacteria. 2-Alkenal reductase and alkenal/alkenone reductase catalyse the reduction of lipid-derived RCs in higher plants. In cyanobacteria, medium-chain dehydrogenases/reductases are the main scavengers of lipid-derived RCs.
The control of blood platelets by cAMP signalling
Authors: Raslan Zaher , Naseem Khalid M.
Published: March 2014

Blood platelet activation must be tightly regulated to ensure a balance between haemostasis and thrombosis. The cAMP signalling pathway is the most powerful endogenous regulator of blood platelet activation. PKA (protein kinase A), the foremost effector of cAMP signalling in platelets, phosphorylates a number of proteins that are thought to modulate multiple aspects of platelet activation. In the present mini-review, we outline our current understanding of cAMP-mediated platelet inhibition and discuss some of the issues that require clarification.
Glycative stress and glyoxalase in kidney disease and aging
Authors: Inagi Reiko
Published: March 2014

Glycation is one of the important reactions regulating physiological state, and glycative stress, namely an overwhelming and unfavourable glycation state, is established as a pathological factor. Glycative stress is closely associated with not only various kidney diseases, but also kidney aging. Accumulating evidence, including studies in my laboratory, demonstrates that progression of renal tubular damage and its aging is correlated with the decrease in the activity of anti-glycative stress enzyme Glo1 (glyoxalase I) in the kidney. The reduction of glycative and oxidative stresses by Glo1 overexpression is beneficial for prevention of kidney disease and treatment, suggesting the novel therapeutic approaches targeting Glo1. The present review is focused on the impact of glycative stress and Glo1 on protein homoeostasis and discusses further the cross-talk between glycative stress and UPR (unfolded protein response), which controls the protein homoeostasis state.
Activity, regulation, copy number and function in the glyoxalase system
Authors: Rabbani Naila , Xue Mingzhan , Thornalley Paul J.
Published: March 2014

Molecular, catalytic and structural properties of glyoxalase pathway enzymes of many species are now known. Current research has focused on the regulation of activity and expression of Glo1 (glyoxalase I) and Glo2 (glyoxalase II) and their role in health and disease. Human GLO1 has MRE (metal-response element), IRE (insulin-response element), E2F4 (early gene 2 factor isoform 4), AP-2α (activating enhancer-binding protein 2α) and ARE (antioxidant response-element) regulatory elements and is a hotspot for copy number variation. The human Glo2 gene, HAGH (hydroxyacylglutathione hydrolase), has a regulatory p53-response element. Glo1 is linked to healthy aging, obesity, diabetes and diabetic complications, chronic renal disease, cardiovascular disease, other disorders and multidrug resistance in cancer chemotherapy. Mathematical modelling of the glyoxalase pathway predicts that pharmacological levels of increased Glo1 activity markedly decrease cellular methylglyoxal and related glycation, and pharmacological Glo1 inhibition markedly increases cellular methylglyoxal and related glycation. Glo1 inducers are in development to sustain healthy aging and for treatment of vascular complications of diabetes and other disorders, and cell-permeant Glo1 inhibitors are in development for treatment of multidrug-resistant tumours, malaria and potentially pathogenic bacteria and fungi.
Possible role of methylglyoxal and glyoxalase in arthritis
Authors: Ahmed Usman , Thornalley Paul J. , Rabbani Naila
Published: March 2014

OA (osteoarthritis) and RA (rheumatoid arthritis) lead to deterioration of the joints. Early OA is associated with loss of bone due to increased bone remodelling. A role for inflammation is thought to be integral to the pathology. RA is a chronic inflammatory disease of the synovium, a membrane lining the non-weight-bearing surfaces of the joint. The mainstay of RA diagnostic testing is for autoantibodies. Rheumatoid factor has been a primary diagnostic test; however, sensitivity is approximately 75%, but specificity is limited. Recently, detection of antibodies against cyclic citrullinated peptide, identified as a screening marker and marker of disease progression, has been proposed. Studies of glycation in arthritis have focused mostly on levels of AGEs (advanced glycation end-products), Nε-carboxymethyl-lysine and pentosidine. There was a weak correlation of skin and urinary pentosidine with joint damage in early-stage OA. RAGE (receptor for AGEs) is a cell-surface receptor in the synovial tissue of patients with OA and RA. The RAGE agonist S100A12 is increased in RA and OA. Activation of RAGE may decrease expression of Glo1 (glyoxalase I). Conflict between RAGE-activated inflammatory signalling and Nrf2 (nuclear factor-erythroid 2-related factor 2) regulation of basal and inducible expression of Glo1 may be involved. Thereby glyoxal- and methylglyoxal-derived AGEs may be increased in OA and RA. Further studies are now required to investigate the role of glyoxalase and dicarbonyl glycation in OA and RA for early-stage diagnosis and potential novel preventive therapy.
Segmental and Prosodic Approaches to Accent Management
Authors: Behrman Alison
Published: March 2014

Purpose

This study investigated the relative outcomes of segmental and prosodic training of nonnative speakers of American English.

Method

The study used a single-subject, alternating treatments, multiple baseline design with replication across participants and counterbalanced for order effect. Participants were 4 adult male native Hindi speakers proficient in English. Two participants received ABABCACA (A = baseline/withdrawal, B = segmental training, C = prosody training), and 2 participants received ACACBABA, with a minimum of 5 sessions per phase. Segmental accuracy and prosodic accuracy were probed at each session, as were perception of accentedness and ease of understanding.

Results

Visual assessment of data and effect size calculation demonstrated that segmental and prosody training resulted in increased accuracy of pronunciation and prosody patterns, respectively, and those improvements appeared to be maintained over the short term. Listeners perceived lesser accent and easier understanding as a result of the combination of segmental and prosody training. The findings are uncertain with respect to the relative contribution of segmental and prosody training, and they may be speaker dependent, but the data do suggest that both components are important.

Conclusion

Accent management, consisting of both segmental and prosody training, yielded positive outcomes. Further research with native language speakers of other languages is important to verify and expand on these findings.
Particle systems and nonlinear Landau damping
Authors: Villani Cédric
Published: March 2014

Some works dealing with the long-time behavior of interacting particle systems are reviewed and put into perspective, with focus on the classical Kolmogorov–Arnold–Moser theory and recent results of Landau damping in the nonlinear perturbative regime, obtained in collaboration with Clément Mouhot. Analogies are discussed, as well as new qualitative insights in the theory. Finally, the connection with a more recent work on the inviscid Landau damping near the Couette shear flow, by Bedrossian and Masmoudi, is briefly discussed.
Heating-induced glass-glass and glass-liquid transformations in computer simulations of water
Authors: Chiu Janet , Starr Francis W. , Giovambattista Nicolas
Published: March 2014

Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T “phase diagram” for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related, both being associated with the limit of kinetic stability of LDA (HDA).
Mobility of singly-charged lanthanide cations in rare gases: Theoretical assessment of the state specificity
Authors: Buchachenko Alexei A. , Viehland Larry A.
Published: March 2014

High quality, ab initio calculations are reported for the potential energy curves governing the interactions of four singly-charged lanthanide ions (Yb+, Eu+, Lu+, and Gd+) with the rare gases (RG = He–Xe). Scalar-relativistic coupled cluster calculations are used for the first three S-state ions, but for Gd+(10D°) it is necessary to take the interaction anisotropy into account with the help of the multi-reference technique. The potential energy curves are used to determine the ion mobility and other transport properties describing the motion of the ions through the dilute RG, both as functions of the temperature, T, in the low-field limit, and at fixed T as functions of the ratio of the electrostatic field strength to the gas number density, E/N. The calculated mobilities are in good agreement with the very limited experimental data that have become available recently. The calculations show a pronounced dependence of the transport properties on the electronic configuration of the ion, as well as a significant effect of the spin-orbit coupling on the transport properties of the Gd+ ion, and predict that state-specific mobilities could be detectable in Gd+–RG experiments.
Ultra-nonlocality in density functional theory for photo-emission spectroscopy
Authors: Uimonen A.-M. , Stefanucci G. , van Leeuwen R.
Published: March 2014

We derive an exact expression for the photocurrent of photo-emission spectroscopy using time-dependent current density functional theory (TDCDFT). This expression is given as an integral over the Kohn-Sham spectral function renormalized by effective potentials that depend on the exchange-correlation kernel of current density functional theory. We analyze in detail the physical content of this expression by making a connection between the density-functional expression and the diagrammatic expansion of the photocurrent within many-body perturbation theory. We further demonstrate that the density functional expression does not provide us with information on the kinetic energy distribution of the photo-electrons. Such information can, in principle, be obtained from TDCDFT by exactly modeling the experiment in which the photocurrent is split into energy contributions by means of an external electromagnetic field outside the sample, as is done in standard detectors. We find, however, that this procedure produces very nonlocal correlations between the exchange-correlation fields in the sample and the detector.
A unifying framework for parameterizing stably stratified shear-flow turbulence
Authors: Mater Benjamin D. , Venayagamoorthy Subhas Karan
Published: March 2014

An alternative framework for parameterizing stably stratified shear-flow turbulence is presented. Using dimensional analysis, four non-dimensional parameters of interest are identified that consider the independent effects of stratification, shear, viscosity, and scalar diffusivity. In the interest of geophysical applications, the problem is further simplified by considering only high Reynolds number flow. This leads to a two-dimensional parameter space based on a buoyancy strength parameter (i.e., an inverse Froude number) and a shear strength parameter. Consideration for the gradient Richardson number allows the space to be divided into an unforced regime, a shear-dominated regime, and a buoyancy-dominated regime. On this basis, a large database of direct numerical simulation and laboratory data from various sources is evaluated. Of particular interest is the observed length scale of overturning. Overturns are found to scale with k1/2/N in the buoyancy-dominated regime, k1/2/S in the shear-dominated regime, and k3/2/ε in the unforced regime, where k, N, S, and ε are the turbulent kinetic energy, buoyancy frequency, mean shear rate, and turbulent kinetic energy dissipation rate, respectively. Implications for estimates of diapycnal mixing in the ocean are discussed and a new parameterization for eddy diffusivity is presented.
Universality and scaling phenomenology of small-scale turbulence in wall-bounded flows
Authors: Wei Liang , Elsinga Gerrit E. , Brethouwer Geert , Schlatter Philipp , Johansson Arne V.
Published: March 2014

The Reynolds number scaling of flow topology in the eigenframe of the strain-rate tensor is investigated for wall-bounded flows, which is motivated by earlier works showing that such topologies appear to be qualitatively universal across turbulent flows. The databases used in the current study are from direct numerical simulations (DNS) of fully developed turbulent channel flow (TCF) up to friction Reynolds number Reτ ≈ 1500, and a spatially developing, zero-pressure-gradient turbulent boundary layer (TBL) up to Reθ ≈ 4300 (Reτ ≈ 1400). It is found that for TCF and TBL at different Reynolds numbers, the averaged flow patterns in the local strain-rate eigenframe appear the same consisting of a pair of co-rotating vortices embedded in a finite-size shear layer. It is found that the core of the shear layer associated with the intense vorticity region scales on the Kolmogorov length scale, while the overall height of the shear layer and the distance between the vortices scale well with the Taylor micro scale. Moreover, the Taylor micro scale collapses the height of the shear layer in the direction of the vorticity stretching. The outer region of the averaged flow patterns approximately scales with the macro scale, which indicates that the flow patterns outside of the shear layer mainly are determined by large scales. The strength of the shear layer in terms of the peak tangential velocity appears to scale with a mixture of the Kolmogorov velocity and root-mean-square of the streamwise velocity scaling. A quantitative universality in the reported shear layers is observed across both wall-bounded flows for locations above the buffer region.
Optical emission spectroscopy of microwave-plasmas at atmospheric pressure applied to the growth of organosilicon and organotitanium nanopowders
Authors: Kilicaslan A. , Levasseur O. , Roy-Garofano V. , Profili J. , Moisan M. , Côté C. , Sarkissian A. , Stafford L.
Published: March 2014

An atmospheric-pressure plasma sustained by an electromagnetic surface wave (SW) in the microwave regime combined with a bubbler/flash evaporator for the injection of liquid precursors was used to produce organosilicon and organotitanium nanopowders. Following the addition of hexamethyldisiloxane (HMDSO) vapors in the nominally pure argon plasma, optical emission spectra revealed the apparition of strong C2 molecular bands along with Si and Balmer H emission lines. Such features were not observed in our atmospheric-pressure Ar/HMDSO discharges controlled by dielectric barriers, indicating that microwave plasmas are characterized by much higher fragmentation levels of the precursors due to much higher electron densities. Emission spectra from the Ar/HMDSO SW plasma further showed a high-intensity continuum, the intensity of which decreased with time as powders started to form on the discharge tube walls. In presence of titanium isopropoxide (TTIP) vapors in the nominally pure Ar plasma, the emission was dominated by Ar and Ti lines, with no trace of carbon and no continuum. Fourier-Transform Infrared (FTIR) Spectroscopy of the powders formed in Ar/HMDSO plasmas showed very strong Si-(CH3)x and O-Si-(CH3)x bands, which is consistent with the formation of silicon oxycarbide. Transmission Electron Microscopy (TEM) further showed tube and sheet-like nanofeatures as well as larger structures consisting of agglomerated primary clusters. On the other hand, introduction of O2 in Ar/HMDSO plasmas produced only round-like nanoparticles with strong Si-O-Si bands and no trace of carbon, consistent with the formation of SiOx. The average size of the silica nanoparticles was 50 nm. FTIR spectra of powders formed in Ar/TTIP plasmas showed strong Ti-O signals, even without the addition of O2 in the gas phase. Corresponding TEM analysis showed nano- and agglomerated features comparable to those obtained in Ar/HMDSO although the average size of the titanate nanoparticles was smaller (10 nm). This set of data indicates that SW plasmas represent a promising parametric tool not only to achieve nanopowders with tailored properties for applications, but also for fundamental studies of nanodusty plasmas at atmospheric-pressure.
Study on the occurrence of spontaneously established perpendicular exchange bias in Co49Pt51/IrMn bilayers
Authors: Tsai C. Y. , Hsu Jen-Hwa , Saravanan P. , Lin K. F.
Published: March 2014

In this study, perpendicular exchange bias (PEB) effect in the as-grown Co49Pt51/IrMn bilayers was demonstrated at room temperature using single-layered Co49Pt51 alloy thin film as ferromagnetic (FM) layer. Several unusual features were observed in this system, viz.,: (i) the PEB was spontaneously established without any external magnetic field treatments, (ii) single-shifted loops were obtained rather than double-shifted ones, and (iii) the spontaneous PEB effect was accompanied by a reduction in perpendicular coercivity, Hc⊥ from 1024 to 632 Oe. The results of x–ray diffraction revealed the formation of IrMn (111) texture. Training effect studies indicate that the PEB effect is stable in this system with less than 5% variation in PEB value within 15 repetitive scans. Significant reduction in the PEB effect was found for the CoPt/IrMn films either grown or subjected to post-annealing under external magnetic field (Hind). The thickness dependence of PEB effect with respect to the FM and antiferromagnetic layers were also investigated and a largest PEB value of 533 Oe was obtained for the sample grown with 3-nm thick CoPt and 10-nm thick IrMn layers. The results of present study thus establish an opportunity to realize PEB effect in the absence of external field during fabrication.
Magnetic properties of Ni-Mn-In-Co Heusler-type glass-coated microwires
Authors: Zhukova V. , Ipatov M. , Granovsky A. , Zhukov A.
Published: March 2014

We report on fabrication and magnetic properties of Heusler-type NiMnInCo glass-coated microwires with metallic nucleus diameters, d, from 13 up to 23 μm and total diameters, D, from 47 to 55 μm by the Taylor-Ulitovsky technique. Considerable dependence of magnetization on magnetic field below and in vicinity of Curie temperature can be related with two-phase structure or with the Hopkinson effect.
Femtosecond single-beam direct laser poling of stable and efficient second-order nonlinear optical properties in glass
Authors: Papon G. , Marquestaut N. , Petit Y. , Royon A. , Dussauze M. , Rodriguez V. , Cardinal T. , Canioni L.
Published: March 2014

We depict a new approach for the localized creation in three dimensions (3D) of a highly demanded nonlinear optical function for integrated optics, namely second harmonic generation. We report on the nonlinear optical characteristics induced by single-beam femtosecond direct laser writing in a tailored silver-containing phosphate glass. The original spatial distribution of the nonlinear pattern, composed of four lines after one single laser writing translation, is observed and modeled with success, demonstrating the electric field induced origin of the second harmonic generation. These efficient second-order nonlinear structures (with χeff(2) ∼ 0.6 pm V−1) with sub-micron scale are impressively stable under thermal constraint up to glass transition temperature, which makes them very promising for new photonic applications, especially when 3D nonlinear architectures are desired.
Quasi-ballistic magnetization switching in Co/Pt dots with perpendicular magnetization
Authors: Kikuchi N. , Suyama Y. , Okamoto S. , Kitakami O. , Shimatsu T.
Published: March 2014

A transverse pulse magnetic field with fast rise time generates precessional motion of magnetization due to finite torque. If the torque is sufficiently large enough magnetization may switch irreversibly via a ballistic trajectory even when energy barrier exists between two energetically stable states. We demonstrate magnetization switching in Co/Pt multilayer nanostructured dots via quasi-ballistic magnetization motion excited by a pulse field with subnanoseconds rise time. The quasi-ballistic switching has been found when the rise time of a pulse field is comparable to the half of magnetization precession period, beating the Stoner–Wohlfarth switching limit.
Temperature dependence of the voltage-controlled perpendicular anisotropy in nanoscale MgO|CoFeB|Ta magnetic tunnel junctions
Authors: Alzate Juan G. , Khalili Amiri Pedram , Yu Guoqiang , Upadhyaya Pramey , Katine Jordan A. , Langer Juergen , Ocker Berthold , Krivorotov Ilya N. , Wang Kang L.
Published: March 2014

In this work, we experimentally study the temperature dependence of the perpendicular magnetic anisotropy (PMA) and of the voltage-controlled magnetic anisotropy (VCMA) in nanoscale MgO|CoFeB|Ta-based magnetic tunnel junctions. We demonstrate that the temperature dependences of both the PMA and the VCMA coefficient follow power laws of the saturation magnetization, but with different exponents. We also find that the linear dependence of the PMA on electric field is maintained over a wide temperature range, although the VCMA strength decreases faster as a function of temperature as compared to the PMA. Possible mechanisms leading to the different exponents are discussed.
PbTe-based thermoelectric nanocomposites with reduced thermal conductivity by SiC nanodispersion
Authors: Li Zong-Yue , Li Jing-Feng , Zhao Wen-Yang , Tan Qing , Wei Tian-Ran , Wu Chao-Feng , Xing Zhi-Bo
Published: March 2014

For further thermoelectric performance enhancement by the nanocomposite effect, a small amount (<2 vol. %) of 30 nm SiC particles were added into a compositionally optimized AgPbmSbTem+2 thermoelectric alloy fabricated by mechanical alloying and spark plasma sintering. Although the energy filtering effect is not available in the present composite due to the mismatched interface between SiC and the matrix, a small amount of SiC dispersions were revealed to be effective to reduce the thermal conductivity via enhancing phonon scattering. A high figure of merit up to 1.54 at 723 K was obtained in the AgPbmSbTem+2 matrix composite containing 1 vol. % SiC nanoparticles.
Pronounced energy absorption capacity of cellular bulk metallic glasses
Authors: Chen S. H. , Chan K. C. , Wu F. F. , Xia L.
Published: March 2014

Cellular bulk metallic glasses (BMGs) with macroscopic cellular structures were designed and fabricated. The cellular BMGs exhibited remarkable energy absorption capacity as compared with reported BMG foams and honeycombs. The enhanced energy absorption capability is attributed to the large plastic bending of the struts, the blunting of the cracks, and the large plastic deformation at the nodes. This work shows that, in cellular BMGs, the macroscopic cellular structures are more efficient in dissipating mechanical energy than microscopic cellular structures, opening a window for developing energy absorption devices using BMGs.