bluuebunny/crossref_metadata_2025 huggingface dataset:
The Legionella pneumophila Collagen-Like Protein Mediates Sedimentation, Autoaggregation, and Pathogen-Phagocyte Interactions
Authors: Abdel-Nour Mena , Duncan Carla , Prashar Akriti , Rao Chitong , Ginevra Christophe , Jarraud Sophie , Low Donald E. , Ensminger Alexander W. , Terebiznik Mauricio R. , Guyard Cyril
Published: December 2013

Although only partially understood, multicellular behavior is relatively common in bacterial pathogens. Bacterial aggregates can resist various host defenses and colonize their environment more efficiently than planktonic cells. For the waterborne pathogen
Legionella pneumophila
, little is known about the roles of autoaggregation or the parameters which allow cell-cell interactions to occur. Here, we determined the endogenous and exogenous factors sufficient to allow autoaggregation to take place in
L. pneumophila
. We show that isolates from
Legionella
species which do not produce the
Legionella
collagen-like protein (Lcl) are deficient in autoaggregation. Targeted deletion of the Lcl-encoding gene (
lpg2644
) and the addition of Lcl ligands impair the autoaggregation of
L. pneumophila
. In addition, Lcl-induced autoaggregation requires divalent cations.
Escherichia coli
producing surface-exposed Lcl is able to autoaggregate and shows increased biofilm production. We also demonstrate that
L. pneumophila
infection of
Acanthamoeba castellanii
and
Hartmanella vermiformis
is potentiated under conditions which promote Lcl dependent autoaggregation. Overall, this study shows that
L. pneumophila
is capable of autoaggregating in a process that is mediated by Lcl in a divalent-cation-dependent manner. It also reveals that Lcl potentiates the ability of
L. pneumophila
to come in contact, attach, and infect amoebae.
The Third Replicon of Members of the Burkholderia cepacia Complex, Plasmid pC3, Plays a Role in Stress Tolerance
Authors: Agnoli Kirsty , Frauenknecht Carmen , Freitag Roman , Schwager Stephan , Jenul Christian , Vergunst Annette , Carlier Aurelien , Eberl Leo
Published: December 2013

The metabolically versatileBurkholderia cepaciacomplex (Bcc) occupies a variety of niches, including the plant rhizosphere and the cystic fibrosis lung (where it is often fatal to the patient). Bcc members have multipartite genomes, of which the third replicon, pC3 (previously chromosome 3), has been shown to be a nonessential megaplasmid which confers virulence and both antifungal and proteolytic activity on several strains. In this study, pC3 curing was extended to cover strains of 16 of the 17 members of the Bcc, and the phenotypes conferred by pC3 were determined.B. cenocepaciastrains H111, MCO-3, and HI2424 were previously cured of pC3; however, this had not proved possible in the epidemic strain K56-2. Here, we investigated the mechanism of this unexpected stability and found that efficient toxin-antitoxin systems are responsible for maintaining pC3 of strain K56-2. Identification of these systems allowed neutralization of the toxins and the subsequent deletion of K56-2pC3. The cured strain was found to exhibit reduced antifungal activity and was attenuated in both the zebrafish and theCaenorhabditis elegansmodel of infection. We used a PCR screening method to examine the prevalence of pC3 within 110 Bcc isolates and found that this replicon was absent in only four cases, suggesting evolutionary fixation. It is shown that plasmid pC3 increases the resistance ofB. cenocepaciaH111 to various stresses (oxidative, osmotic, high-temperature, and chlorhexidine-induced stresses), explaining the prevalence of this replicon within the Bcc.
Role of the Apt1 Protein in Polysaccharide Secretion by Cryptococcus neoformans
Authors: Rizzo Juliana , Oliveira Débora L. , Joffe Luna S. , Hu Guanggan , Gazos-Lopes Felipe , Fonseca Fernanda L. , Almeida Igor C. , Frases Susana , Kronstad James W. , Rodrigues Marcio L.
Published: December 2013

Flippases are key regulators of membrane asymmetry and secretory mechanisms. Vesicular polysaccharide secretion is essential for the pathogenic mechanisms of
Cryptococcus neoformans
. On the basis of the observations that flippases are required for polysaccharide secretion in plants and the putative Apt1 flippase is required for cryptococcal virulence, we analyzed the role of this enzyme in polysaccharide release by
C. neoformans
, using a previously characterized
apt1
Δ mutant. Mutant and wild-type (WT) cells shared important phenotypic characteristics, including capsule morphology and dimensions, glucuronoxylomannan (GXM) composition, molecular size, and serological properties. The
apt1
Δ mutant, however, produced extracellular vesicles (EVs) with a lower GXM content and different size distribution in comparison with those of WT cells. Our data also suggested a defective intracellular GXM synthesis in mutant cells, in addition to changes in the architecture of the Golgi apparatus. These findings were correlated with diminished GXM production during
in vitro
growth, macrophage infection, and lung colonization. This phenotype was associated with decreased survival of the mutant in the lungs of infected mice, reduced induction of interleukin-6 (IL-6) cytokine levels, and inefficacy in colonization of the brain. Taken together, our results indicate that the lack of
APT1
caused defects in both GXM synthesis and vesicular export to the extracellular milieu by
C. neoformans
via processes that are apparently related to the pathogenic mechanisms used by this fungus during animal infection.
Detailed Identification of Fatty Acid Isomers Sheds Light on the Probable Precursors of Triacylglycerol Accumulation in Photoautotrophically Grown Chlamydomonas reinhardtii
Authors: Sakurai Kenta , Moriyama Takashi , Sato Naoki
Published: December 2013

Chlamydomonas reinhardtii
is a model alga for studying triacylglycerol (TAG) accumulation in the photosynthetic production of biofuel. Previous studies were conducted under photoheterotrophic growth conditions in medium supplemented with acetate and/or ammonium. We wanted to demonstrate TAG accumulation under truly photoautotrophic conditions without reduced elements. We first reidentified all lipid components and fatty acids by mass spectrometry, because the currently used identification knowledge relies on data obtained in the 1980s. Accordingly, various isomers of fatty acids, which are potentially useful in tracing the flow of fatty acids leading to the accumulation of TAG, were detected. In strain CC1010 grown under photoautotrophic conditions, TAG accumulated to about 57.5 mol% of total lipids on a mole fatty acid basis after the transfer to nitrogen-deficient conditions. The content of monogalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol, and phosphatidylglycerol decreased drastically. The accumulated TAG contained 16:0 as the major acid and 16:4(4,7,10,13), 18:2(9,12), and 18:3(9,12,15), which are typically found in chloroplast lipids. Additionally, 18:1(11) and 18:3(5,9,12), which are specific to extrachloroplast lipids, were also abundant in the accumulated TAG. Photosynthesis and respiration slowed markedly after the shift to nitrogen-deficient conditions. These results suggest that fatty acids for the production of TAG were supplied not only from chloroplast lipids but also from other membranes within the cells, although the possibility of
de novo
synthesis cannot be excluded. Under nitrogen-replete conditions, supplementation with a high concentration of CO
2
promoted TAG production in the cells grown photoautotrophically, opening up the possibility to the continuous production of TAG using CO
2
produced by industry.
Draft Genome Sequence of
Enterococcus
sp. Strain HSIEG1, Isolated from the Human Small Intestine
Authors: van den Bogert Bartholomeus , Boekhorst Jos , Smid Eddy J. , Zoetendal Erwin G. , Kleerebezem Michiel
Published: December 2013

Enterococcus
sp. strain HSIEG1 was isolated from the human small intestine. Its draft genome predicts a broad carbohydrate fermentation capability, which matches well with the observed physiological characteristics of this strain. This metabolic flexibility is expected to be of importance for survival and growth in the small intestinal habitat.
The EutT Enzyme of Salmonella enterica Is a Unique ATP:Cob(I)alamin Adenosyltransferase Metalloprotein That Requires Ferrous Ions for Maximal Activity
Authors: Moore Theodore C. , Mera Paola E. , Escalante-Semerena Jorge C.
Published: December 2013

ATP:co(I)rrinoid adenosyltransferase (ACAT) enzymes convert vitamin B
12
to coenzyme B
12
. EutT is the least understood ACAT. We report the purification of EutT to homogeneity and show that,
in vitro
, free dihydroflavins drive the adenosylation of cob(II)alamin bound to EutT. Results of chromatography analyses indicate that EutT is dimeric in solution, and unlike other ACATs, EutT catalyzes the reaction with sigmoidal kinetics indicative of positive cooperativity for cob(II)alamin. Maximal EutT activity was obtained after metalation with ferrous ions. EutT/Fe(II) protein lost all activity upon exposure to air and H
2
O
2
, consistent with previously reported results indicating that EutT was an oxygen-labile metalloprotein containing a redox-active metal. Results of
in vivo
and
in vitro
analyses of single-amino-acid variants affecting a HX
11
CCXXC
83
motif conserved in EutT proteins showed that residues His67, Cys80, and Cys83 were required for EutT function
in vivo
, while Cys79 was not. Unlike that of other variants, the activity of the EutT
C80A
variant was undetectable
in vitro
, suggesting that Cys80 was critical to EutT function. Results of circular dichroism studies indicate that the presence or absence of a metal ion does not affect protein folding. EutT can now be purified in the presence of oxygen and reactivated with ferrous ions for maximal activity.
Profile, cost and pattern of prescriptions for polymedicated patients in Catalonia, Spain
Authors: Lizano-Díez Irene , Modamio Pilar , López-Calahorra Pilar , Lastra Cecilia F , Gilabert-Perramon Antoni , Segú Jose L , Mariño Eduardo L
Published: December 2013

Objectives

Polypharmacy is one of the main management issues in public health policies because of its financial impact and the increasing number of people involved. The polymedicated population according to their demographic and therapeutic profile and the cost for the public healthcare system were characterised.

Design

Cross-sectional study.

Setting

Primary healthcare in Barcelona Health Region, Catalonia, Spain (5 105 551 inhabitants registered).

Participants

All insured polymedicated patients. Polymedicated patients were those with a consumption of ≥16 drugs/month.

Main outcomes measures

The study variables were related to age, gender and medication intake obtained from the 2008 census and records of prescriptions dispensed in pharmacies and charged to the public health system.

Results

There were 36 880 polymedicated patients (women: 64.2%; average age: 74.5±10.9 years). The total number of prescriptions billed in 2008 was 2 266 830 (2 272 920 total package units). The most polymedicated group (up to 40% of the total prescriptions) was patients between 75 and 84 years old. The average number of prescriptions billed monthly per patient was 32±2, with an average cost of €452.7±27.5. The total cost of those prescriptions corresponded to 2% of the drug expenditure in Catalonia. The groups N, C, A, R and M represented 71.4% of the total number of drug package units dispensed to polymedicated patients. Great variability was found between the medication profiles of men and women, and between age groups; greater discrepancies were found in paediatric patients (5–14 years) and the elderly (≥65 years).

Conclusions

This study provides essential information to take steps towards rational drug use and a structured approach in the polymedicated population in primary healthcare.
Promoting engagement by patients and families to reduce adverse events in acute care settings: a systematic review
Authors: Berger Zackary , Flickinger Tabor E , Pfoh Elizabeth , Martinez Kathryn A , Dy Sydney M
Published: December 2013

Introduction

Patient-centeredness is central to healthcare. Hospitals should address patients’ unique needs to improve safety and quality. Patient engagement in healthcare, which may help prevent adverse events, can be approached as an independent patient safety practice (PSP) or as part of a multifactorial PSP.

Objectives

This review examines how interventions encouraging this engagement have been implemented in controlled trials.

Methods

We searched Medline, CINAHL, Embase and Cochrane from 2000 to 2012 for English language studies in hospital settings with prospective controlled designs, addressing the effectiveness or implementation of patient/family engagement in PSPs. We separately reviewed interventions implemented as part of selected broader PSPs by way of example: hand hygiene, ventilator-associated pneumonia, rapid response systems and care transitions.

Results

Six articles met the inclusion criteria for effectiveness with a primary focus on patient engagement. We identified 12 studies implementing patient engagement as an aspect of selected broader PSPs. A number of studies relied on patients’ possible function as a reporter of error to healthcare workers and patients as a source of reminders regarding safety behaviours, while others relied on direct activation of patients or families. Definitions of patient and family engagement were lacking, as well as evidence regarding the types of patients who might feel comfortable engaging with providers, and in what contexts.

Conclusions

While patient engagement in safety is appealing, there is insufficient high-quality evidence informing real-world implementation. Further work should evaluate the effectiveness of interventions on patient and family engagement and clarify the added benefit of incorporating engagement in multifaceted approaches to improve patient safety endpoints. In addition, strategies to assess and overcome barriers to patients’ willingness to actively engage in their care should be investigated.
Patient Satisfaction: Receiving a copy of the GP letter following fracture or elective orthopaedic clinic
Authors: Pinder Elizabeth , Jefferys S , Loeffler Mark
Published: December 2013

Following orthopaedic/fracture clinics at our hospital, patients now receive a copy of the letter summarizing an outpatient consultation that is sent to their General Practitioner. We undertook a patient satisfaction questionnaire to determine if patients found this change in practice beneficial.

Of the 83 patients who had received this letter, most patients had read the letter (96%) and understood the content (90%). 13% were worried after having read the content and 86% found it helpful. Of the 40 patients who did not receive a copy, 32 (80%) specified that they would wish to in the future. The results support the new practice although it could be improved by identifying those who do not wish to be included thereby reducing costs.
Effect of period, water temperature and agitation on loss of water‐soluble carbohydrates and protein from grass hay: implications for equine feeding management
Authors: Longland A. C. , Barfoot C. , Harris P. A.
Published: December 2013

The effects of different water‐soaking treatments on removal of water‐soluble carbohydrates (WSC), WSC constituents and protein from four UK hays were determined. Hays were soaked in water for up to 16 hours at mean temperatures of 8°C, 16°C, in hot tap water (initially 49°C) or agitated and rinsed in clean water at 16°C. Initial hay WSC contents ranged from 154 to 216 g/kg dry matter. Losses of WSC from hays after 16 hours soaking at 8°C, 16°C, 16°C plus agitation and 49°C averaged 28, 46, 49 and 44 per cent, respectively. Corresponding percentage losses of fructan were 16, 37, 39 and 33. Percentage losses of sucrose averaged 55 (8°C), 86 (16°C), 91 (16°C+agitation) and 82 (initial temperature 49°C), those of glucose were 60, 85, 75 and 75, and of fructose were 41, 52, 54 and 46. Hay crude protein contents were not significantly changed by any of the soaking treatments. Soaking at 8°C generally resulted in reduced losses of WSC compared to when soaked at the higher temperatures. Thus, in cold weather using warmer water to soak hays may effect greater WSC loss, although very prolonged soaking at warm temperatures might encourage the proliferation of unwanted micro‐organisms in the soak liquor.
Suspected adverse events, 2012
Authors: Davis G. , Rooney A. , Cooles S. , Evans G.
Published: December 2013

Increase in serious adverse events

Increase in reports involving products marketed under the Small Animal Exemption Scheme

Decrease in injection site reactions

These are some of the results from the surveillance work carried out by the pharmacovigilance unit at the Veterinary Medicines Directorate (VMD), as discussed by Giles Davis and colleagues
Novel environmental conditions alter subsidy and engineering effects by introduced Pacific salmon
Authors: Janetski David J. , Chaloner Dominic T. , Moerke Ashley H. , Levi Peter S. , Lamberti Gary A.
Published: December 2013

We demonstrate that the major ecological functions of Pacific salmon (Oncorhynchus spp.) can be altered or re-ordered in non-native habitats where environmental conditions differ from native ranges. We compared subsidy and engineering effects of spawning Pacific salmon in six streams within their introduced range (Laurentian Great Lakes) with responses reported in their native range (northern Pacific Rim). Streamwater nutrient responses (i.e., subsidy effects) in Great Lakes streams were generally weak compared with those reported in native streams, whereas disturbance (i.e., engineering effects) was often strong where salmon were abundant. We attribute the relatively weak nutrient response to high background nutrient concentrations and low salmon biomass. In contrast, in Great Lakes streams with high salmon biomass, sediment routing was intense and pervasive and, consequently, benthic biofilm and macroinvertebrate abundance often declined by over 90% during the salmon run. These strong disturbance effects were likely facilitated by the small sediments that typified the Great Lakes streams. Our study provides evidence that salmon effects are context-dependent at much broader spatial scales than has been reported previously.
Mitochondrial permeability transition pore plays a role in the cardioprotection of CB2 receptor against ischemia–reperfusion injury
Authors: Li Qian , Guo Hui-cai , Maslov Leonid N. , Qiao Xiao-wen , Zhou Jing-jing , Zhang Yi
Published: December 2013

The aim of this study was to investigate whether the mitochondrial permeability transition pore (MPTP) opening was involved in the protective effects of CB2 receptor against ischemia–reperfusion (I-R) injury. For this, isolated perfused rat hearts were subjected to 30 min global ischemia followed by 120 min reperfusion, and left ventricle function was recorded. At the end of reperfusion, the infarct size in the hearts was measured by staining with triphenyltetrazolium chloride. MPTP opening and the mitochondrial membrane potential (ΔΨm) were measured by flow cytometry. Western blot analysis of cytochrome c in the mitochondrion and cytosol, as well as ERK1/2 and p-ERK1/2 were performed. Administration of CB2 receptor agonist JWH133 before ischemia significantly improved the recovery of cardiac ventricular function during reperfusion, increased coronary flow, reduced infarct size, prevented the loss of ΔΨm and MPTP opening, reduced the release of cytochrome c from mitochondria, and increased levels of p-ERK1/2. These effects of JWH133 were abolished by pretreatment with CB2 receptor antagonist AM630, or ERK1/2 inhibitor PD98059. Furthermore, JWH133 reversed the MPTP opening induced by atractyloside. The protective effect of JWH133 on the heart against I-R injury may be through increased ERK1/2 phosphorylation, inhibiting MPTP opening.
ON THE MIDWAY TO EPILEPSY: IS CORTICAL EXCITABILITY NORMAL IN PATIENTS WITH ISOLATED SEIZURES?
Authors: BADAWY RADWA A. B. , VOGRIN SIMON J. , LAI ALAN , COOK MARK J.
Published: December 2013

Paired pulse transcranial magnetic stimulation was used to investigate differences in cortical excitability between patients with isolated (unrecurrent, unprovoked) seizures and those with epilepsy. Compared to controls, cortical excitability was higher in the isolated seizure group at 250–300 ms. Compared to epilepsy, cortical excitability was lower in patients with isolated seizures also at 250 and 300 ms. Lowered seizure threshold caused by disturbances within inhibitory circuits is present in patients who experience a seizure even if no further seizures occur.
SEPARATING BURST FROM BACKGROUND SPIKES IN MULTICHANNEL NEURONAL RECORDINGS USING RETURN MAP ANALYSIS
Authors: MARTENS M. B. , CHIAPPALONE M. , SCHUBERT D. , TIESINGA P. H. E.
Published: December 2013

We propose a preprocessing method to separate coherent neuronal network activity, referred to as "bursts", from background spikes. High background activity in neuronal recordings reduces the effectiveness of currently available burst detection methods. For long-term, stationary recordings, burst and background spikes have a bimodal ISI distribution which makes it easy to select the threshold to separate burst and background spikes. Finite, nonstationary recordings lead to noisy ISIs for which the bimodality is not that clear. We introduce a preprocessing method to separate burst from background spikes to improve burst detection reliability because it efficiently uses both single and multichannel activity. The method is tested using a stochastic model constrained by data available in the literature and recordings from primary cortical neurons cultured on multielectrode arrays. The separation between burst and background spikes is obtained using the interspike interval return map. The cutoff threshold is the key parameter to separate the burst and background spikes. We compare two methods for selecting the threshold. (1) The 2-step method, in which threshold selection is based on fixed heuristics. (2) The iterative method, in which the optimal cutoff threshold is directly estimated from the data. The proposed preprocessing method significantly increases the reliability of several established burst detection algorithms, both for simulated and real recordings. The preprocessing method makes it possible to study the effects of diseases or pharmacological manipulations, because it can deal efficiently with nonstationarity in the data.
FREQUENCY RECOGNITION IN SSVEP-BASED BCI USING MULTISET CANONICAL CORRELATION ANALYSIS
Authors: ZHANG YU , ZHOU GUOXU , JIN JING , WANG XINGYU , CICHOCKI ANDRZEJ
Published: December 2013

Canonical correlation analysis (CCA) has been one of the most popular methods for frequency recognition in steady-state visual evoked potential (SSVEP)-based brain–computer interfaces (BCIs). Despite its efficiency, a potential problem is that using pre-constructed sine-cosine waves as the required reference signals in the CCA method often does not result in the optimal recognition accuracy due to their lack of features from the real electro-encephalo-gram (EEG) data. To address this problem, this study proposes a novel method based on multiset canonical correlation analysis (MsetCCA) to optimize the reference signals used in the CCA method for SSVEP frequency recognition. The MsetCCA method learns multiple linear transforms that implement joint spatial filtering to maximize the overall correlation among canonical variates, and hence extracts SSVEP common features from multiple sets of EEG data recorded at the same stimulus frequency. The optimized reference signals are formed by combination of the common features and completely based on training data. Experimental study with EEG data from 10 healthy subjects demonstrates that the MsetCCA method improves the recognition accuracy of SSVEP frequency in comparison with the CCA method and other two competing methods (multiway CCA (MwayCCA) and phase constrained CCA (PCCA)), especially for a small number of channels and a short time window length. The superiority indicates that the proposed MsetCCA method is a new promising candidate for frequency recognition in SSVEP-based BCIs.
STABILITY OF SPACELIKE HYPERSURFACES WITH HIGHER-ORDER MEAN CURVATURES LINEARLY RELATED IN CONFORMALLY STATIONARY SPACETIMES
Authors: DE LIMA HENRIQUE FERNANDES , DE SOUSA ANTONIO FERNANDO , VELÁSQUEZ MARCO ANTONIO LÁZARO
Published: December 2013

In this paper, we establish the notion of (r, s)-stability concerning spacelike hypersurfaces with higher-order mean curvatures linearly related in conformally stationary spacetimes of constant sectional curvature. In this setting, we characterize (r, s)-stable closed spacelike hypersurfaces through the analysis of the first eigenvalue of an operator naturally attached to the higher-order mean curvatures. Moreover, we obtain sufficient conditions which assure the (r, s)-stability of complete spacelike hypersurfaces immersed in the de Sitter space.
ON DIVISION OF QUASIANALYTIC FUNCTION GERMS
Authors: NOWAK KRZYSZTOF JAN
Published: December 2013

We establish the following criterion for divisibility in the local ring [Formula: see text] of those quasianalytic function germs at 0 ∈ ℝnwhich are definable in a polynomially bounded structure. A sufficient (and necessary) condition for the divisibility of two function germs in [Formula: see text] is that of their Taylor series at 0 ∈ ℝnin the formal power series ring.
A model of language inflection graphs
Authors: Fukś Henryk , Farzad Babak , Cao Yi
Published: December 2013

Inflection graphs are highly complex networks representing relationships between inflectional forms of words in human languages. For so-called synthetic languages, such as Latin or Polish, they have particularly interesting structure due to the abundance of inflectional forms. We construct the simplest form of inflection graphs, namely a bipartite graph in which one group of vertices corresponds to dictionary headwords and the other group to inflected forms encountered in a given text. We, then, study projection of this graph on the set of headwords. The projection decomposes into a large number of connected components, to be called word groups. Distribution of sizes of word group exhibits some remarkable properties, resembling cluster distribution in a lattice percolation near the critical point. We propose a simple model which produces graphs of this type, reproducing the desired component distribution and other topological features.
A honeycomb model for tortuosity of flow path in the leaf venation network
Authors: Liu Han , Zou Ming-Qing , Wang Da-Lun , Yang Shan-Shan , Liang Ming-Chao
Published: December 2013

A honeycomb model is designed according to the leaf veins, which is expressed as a function of porosity and tortuosity, and there is no empirical constant in this model. We mainly applied it to the leaf venation network, and the prediction in our model are compared with that from available correlations obtained by matching the numerical results, both of which are consistent with each other. Our model and relations may have important significance and potential applications in leaf venation and porous media. They also have a certain guiding significance to fluid heat transfer and thermal diffusion, as well as biotechnology research, e.g. veins and the neural networks of human.
An analysis of intergroup rivalry using Ising model and reinforcement learning
Authors: Zhao Feng-Fei , Qin Zheng , Shao Zhuo
Published: December 2013

Modeling of intergroup rivalry can help us better understand economic competitions, political elections and other similar activities. The result of intergroup rivalry depends on the co-evolution of individual behavior within one group and the impact from the rival group. In this paper, we model the rivalry behavior using Ising model. Different from other simulation studies using Ising model, the evolution rules of each individual in our model are not static, but have the ability to learn from historical experience using reinforcement learning technique, which makes the simulation more close to real human behavior. We studied the phase transition in intergroup rivalry and focused on the impact of the degree of social freedom, the personality of group members and the social experience of individuals. The results of computer simulation show that a society with a low degree of social freedom and highly educated, experienced individuals is more likely to be one-sided in intergroup rivalry.
An efficient routing strategy on spatial scale-free networks
Authors: Guan Xiang-Min , Zhang Xue-Jun , Zhu Yanbo , Hwang Inseok , Sun Deng-Feng
Published: December 2013

Traffic dynamics has drawn much more attention recently, but most current research barely considers the space factor, which is of critical importance in many real traffic systems. In this paper, we focus our research on traffic dynamics of a spatial scale-free network with the restriction of bandwidth proportional to link Euclidean distance, and a new routing strategy is proposed with consideration of both Euclidean distance and betweenness centralities (BC) of edges. It is found that compared with the shortest distance path (SDP) strategy and the minimum betweenness centralities (MBC) of links strategy, our strategy under some parameters can effectively balance the traffic load and avoid excessive traveling distance which can improve the spatial network capacity and some system behaviors reflecting transportation efficiency, such as average packets traveling time, average packets waiting time and system throughput, traffic load and so on. Besides, though the restriction of bandwidth can trigger congestion, the proposed routing strategy always has the best performance no matter what bandwidth becomes. These results can provide insights for research on real networked traffic systems.
First principles calculations on structural, elastic, acoustic and optical properties of fluorite phase TiO2 under pressure
Authors: Mahmood Waqas , Zhao Qing
Published: December 2013

The electronic, elastic, acoustic and optical properties of fluorite phase TiO 2 are calculated by using the first principles method. Different exchange-correlation functionals are used with the ultrasoft plane wave pseudopotential method under pressure from 0 GPa to 90 GPa. The calculated values of the lattice constant, cell volume, bandgap, bulk modulus and the pressure derivative of bulk modulus are in agreement with the prior published results. The calculated elastic parameters show that the fluorite structure is mechanically stable, the ratio of bulk to shear modulus [Formula: see text] indicates that it is brittle, and pressure derivative of the bulk modulus shows that it is not a super hard material, but a hard material. The longitudinal and transverse acoustic velocities in the direction [100], [110] and [111] are computed by using prior determined data. Besides, the optical properties are also studied under the aforementioned range of pressure, and the results show more photolytic activity over the other phases.
SHEDDING LIGHT ON DARK MATTER AT COLLIDERS
Authors: MITSOU VASILIKI A.
Published: December 2013

Dark matter remains one of the most puzzling mysteries in Fundamental Physics of our times. Experiments at high-energy physics colliders are expected to shed light to its nature and determine its properties. This review focuses on recent searches for dark matter signatures at the Large Hadron Collider, also discussing related prospects in future e+e- colliders.
NUMERICAL ANALYSIS AND COMPARISON OF SPECTRAL DECOMPOSITION METHODS IN BIOMETRIC APPLICATIONS
Authors: FERNÁNDEZ-MARTÍNEZ JUAN LUIS , CERNEA ANA
Published: December 2013

Face recognition is a challenging problem in computer vision and artificial intelligence. One of the main challenges consists in establishing a low-dimensional feature representation of the images having enough discriminatory power to perform high accuracy classification. Different methods of supervised and unsupervised classification can be found in the literature, but few numerical comparisons among them have been performed on the same computing platform. In this paper, we perform this kind of comparison, revisiting the main spectral decomposition methods for face recognition. We also introduce for the first time, the use of the noncentered PCA and the 2D discrete Chebyshev transform for biometric applications. Faces are represented by their spectral features, that is, their projections onto the different spectral basis. Classification is performed using different norms and/or the cosine defined by the Euclidean scalar product in the space of spectral attributes. Although this constitutes a simple algorithm of unsupervised classification, several important conclusions arise from this analysis: (1) All the spectral methods provide approximately the same accuracy when they are used with the same energy cutoff. This is an important conclusion since many publications try to promote one specific spectral method with respect to other methods. Nevertheless, there exist small variations on the highest median accuracy rates: PCA, 2DPCA and DWT perform better in this case. Also all the covariance-free spectral decomposition techniques based on single images (DCT, DST, DCHT, DWT, DWHT, DHT) are very interesting since they provide high accuracies and are not computationally expensive compared to covariance-based techniques. (2) The use of local spectral features generally provide higher accuracies than global features for the spectral methods which use the whole training database (PCA, NPCA, 2DPCA, Fisher's LDA, ICA). For the methods based on orthogonal transformations of single images, global features calculated using the whole size of the images appear to perform better. (3) The distance criterion generally provides a higher accuracy than the cosine criterion. The use of other p-norms (p > 2) provides similar results to the Euclidean norm, nevertheless some methods perform better. (4) No spectral method can provide 100% accuracy by itself. Therefore, other kind of attributes and supervised learning algorithms are needed. These results are coherent for the ORL and FERET databases. Finally, although this comparison has been performed for the face recognition problem, it could be generalized to other biometric authentication problems.
SMALL DISCOVERIES CAN HAVE GREAT CONSEQUENCES IN LOVE AFFAIRS: THE CASE OF BEAUTY AND THE BEAST
Authors: RINALDI SERGIO , LANDI PIETRO , ROSSA FABIO DELLA
Published: December 2013

A mathematical model is proposed for interpreting the love story portrayed by Walt Disney in the film "Beauty and The Beast". The analysis shows that the story is characterized by a sudden explosion of sentimental involvements, revealed by the existence of a saddle-node bifurcation in the model. The paper is interesting not only because it deals for the first time with catastrophic bifurcations in specific romantic relationships, but also because it enriches the list of examples in which love stories are satisfactorily described through Ordinary Differential Equations.
SIMPLE CHAOTIC FLOWS WITH ONE STABLE EQUILIBRIUM
Authors: MOLAIE MALIHE , JAFARI SAJAD , SPROTT JULIEN CLINTON , GOLPAYEGANI S. MOHAMMAD REZA HASHEMI
Published: December 2013

Using the Routh–Hurwitz stability criterion and a systematic computer search, 23 simple chaotic flows with quadratic nonlinearities were found that have the unusual feature of having a coexisting stable equilibrium point. Such systems belong to a newly introduced category of chaotic systems with hidden attractors that are important and potentially problematic in engineering applications.
WHEN ARE GRADED INTEGRAL DOMAINS ALMOST GCD-DOMAINS
Authors: LIM JUNG WOOK
Published: December 2013

Let R = ⨁α∈Γ Rα be a (Γ-)graded integral domain and let H be the multiplicatively closed set of nonzero homogeneous elements of R. In this paper, we introduce the concepts of graded almost GCD-domains (graded AGCD-domain) and graded almost Prüfer v-multiplication domains (graded AP v MD ). Among other things, we show that if R is integrally closed, then (1) H is an almost lcm splitting set of R if and only if R is a graded AGCD-domain and (2) R is a graded AP v MD if and only if R is a P v MD . We also give an example of a (non-integrally closed) graded AGCD-domain (respectively, graded AP v MD ) that is not an almost GCD-domain (respectively, almost Prüfer v-multiplication domain.
SEIFERT FIBERED KNOT MANIFOLDS
Authors: HILLMAN J. A. , HOWIE J.
Published: December 2013

We consider the question of when is the closed manifold obtained by elementary surgery on an n-knot Seifert fibered over a 2-orbifold. The possible bases are strongly constrained by the fact that knot groups have weight 1. We present a new family of 2-knots with solvable groups, overlooked in earlier work. The knots in this new family are neither invertible nor amphicheiral, and the weight orbits for the knot groups are parametrized by ℤ. There are no known examples in higher dimensions.
STUDY ON SINGLE-MODE EXCITATION IN TIME-VARIANT SHALLOW WATER ENVIRONMENT
Authors: PENG DAYONG , GAO TIANFU , ZENG JUAN
Published: December 2013

Single-mode excitation is a powerful tool for studying many oceanographic processes. Meanwhile, the complex time-variant ocean environment poses a great challenge for single-mode excitation because Green's function matrix of sound field changes quickly. In their previous work, the authors built a system to excite single-mode in a relative simple environment. The purpose of this paper is to study the feasibility of single-mode excitation in rapidly time-variant ocean environment. An improved recursive algorithm is presented to adapt for time-variant environment where the single-mode can be excited within very short time by this algorithm. A typical time-variant shallow water environment is simulated, and results of the single-mode excitation in this environment are presented.
ACOUSTIC TRAVEL-TIME PERTURBATIONS DUE TO SHALLOW-WATER INTERNAL WAVES IN THE YELLOW SEA
Authors: LI FAN , GUO XINYI , HU TAO , MA LI
Published: December 2013

Internal waves in shallow-water cause variations in sound speed profiles and lead to acoustic travel-time perturbations. In summer 2007, a combined acoustics/physical oceanography experiment was performed to study both the acoustical properties and the ocean dynamics of the Yellow Sea. The internal waves were recorded by the thermistor arrays. The receiving hydrophone array is enabled to monitor the acoustic travel-time fluctuations over the internal wave activities. It is shown that the activity of high frequency internal waves (having 3–6 min period) dominated the travel time perturbation. In this paper, we compare the data of high frequency internal wave with acoustic travel-time perturbation data and analyze the correlation between them. A simple relation between the modal travel-time perturbation and the displacement of the thermocline is developed which might be useful for monitoring purposes.
Shape Optimization Under Vibroacoustic Criteria in the Mid-High Frequency Range
Authors: Troian Renata , Besset Sebastien , Gillot Frederic
Published: December 2013

This paper deals with shape optimization issues under vibroacoustic criteria. The aim of the conducted research is to minimize the energy density in the cavity by changing its geometry parameters. The energy density is obtained through an energy method called simplified energy method (MES). The optimization method is based on a transformation function mapping 3D cavity surface on a 2D domain. The optimization process directly relies on this function and thus avoids remeshing of the geometry. The proposed method allows to describe the geometry through Bezier, Bspline and NURBS parametrization. To illustrate the method, we process a shape optimization on a simple acoustic cavity.
Numerical Mode Matching Approach for Acoustic Attenuation Predictions of Double-Chamber Perforated Tube Dissipative Silencers with Mean Flow
Authors: Fang Z. , Ji Z. L.
Published: December 2013

The transfer matrix method (TMM) based on numerical mode matching (NMM) approach is developed to investigate the acoustic behavior of double-chamber perforated tube dissipative silencer with mean flow. The present method is verified by comparing the transmission loss (TL) predictions and experimental data. Then the effects of mean flow, perforated tube offset and lengths of perforations are studied computationally. As the Mach number increases, the TL of dissipative silencer is lowered at most frequencies. The perforated tube offset may change the acoustic behavior in the mid-high frequency range. Increasing the total length of perforations increases TL at the mid-high frequencies.
MERCURY ADSORPTION ON SULFURIC ACID-IMPREGNATED CARBONACEOUS SURFACE: THEORETICAL STUDY
Authors: HE PING , WU JIANG , JIANG XIUMIN , PAN WEIGUO , REN JIANXING
Published: December 2013

Density functional theory calculations are performed to provide a molecular-level understanding of the mechanism of mercury adsorption on sulfuric acid-impregnated carbonaceous surface. The carbonaceous surface is modeled by a nine-fused benzene ring in which its edge carbon atoms on the upper side are unsaturated to simulate the active sites for reaction. SO 4 clusters with and without charge are examined to act as the representative species to model the sulfuric acid absorbed on the carbonaceous surface. All of the possible approaches of SO 4 clusters with and without charge on the carbonaceous surface are conduced to study their effects on mercury adsorption. The results suggest that sulfuric acid effect on the mercury adsorption capacity of the carbonaceous surface is very complicated, and it depends on a combination of concentration and charge of SO 4 cluster. SO 4 cluster presents a positive effect on mercury adsorption on the carbonaceous surface, but higher concentration of SO 4 cluster decreases the adsorption capacity of the carbonaceous surface for mercury removal because there is considerable competition for active sites between Hg and SO 4 cluster. Since all of the possible approaches of mercury on the carbonaceous surface with [Formula: see text] cluster, excluding one that mercury is adsorbed at bridge active site, can lead to the decrease in the adsorption energies of mercury on the carbonaceous surface, [Formula: see text] cluster presents a negative effect on the capacity of the carbonaceous surface for mercury adsorption regardless of the concentration of [Formula: see text] cluster. The results also indicate that SO 2 cluster and surface oxygen complex can be formed from SO 4 cluster with or without charge if mercury is adsorbed at bridge active site, which facilitates the mercury removal for the carbonaceous surface.
STUDY ON DECOMPOSITION OF GOETHITE/SIDERITE IN THERMAL MODIFICATION THROUGH XRD, SEM AND TGA MEASUREMENTS
Authors: SONG SHAOXIAN , JIA FEIFEI , PENG CHANGSHENG
Published: December 2013

The decomposition of goethite and goethite/siderite concentrates into hematite with thermal modification was studied through the measurements of X-ray diffraction (XRD), scanning electronic microscope (SEM) and thermal gravimetric analysis (TGA). The experimental results showed that goethite decomposed into hematite directly at around 300°C without any intermediate phase and the decomposition of siderite completed at 500°C. Nanoscale granular structures were observed in the thermally treated products. It deserves highlighting that the decomposition processes proceeded from surfaces into bulks.
On simpleness of semirings and complete semirings
Authors: Katsov Yefim , Nam Tran Giang , Zumbrägel Jens
Published: December 2013

In this paper, we investigate various classes of semirings and complete semirings regarding the property of being ideal-simple, congruence-simple, or both. Among other results, we describe (complete) simple, i.e. simultaneously ideal- and congruence-simple, endomorphism semirings of (complete) idempotent commutative monoids; we show that the concepts of simpleness, congruence-simpleness, and ideal-simpleness for (complete) endomorphism semirings of projective semilattices (projective complete lattices) in the category of semilattices coincide iff those semilattices are finite distributive lattices; we also describe congruence-simple complete hemirings and left artinian congruence-simple complete hemirings. Considering the relationship between the concepts of "Morita equivalence" and "simpleness" in the semiring setting, we obtain the following further results: The ideal-simpleness, congruence-simpleness, and simpleness of semirings are Morita invariant properties; a complete description of simple semirings containing the infinite element; the "Double Centralizer Property" representation theorem for simple semirings; a complete description of simple semirings containing a projective minimal one-sided ideal; a characterization of ideal-simple semirings having either an infinite element or a projective minimal one-sided ideal; settling a conjecture and a problem as published by Katsov in 2004 for the classes of simple semirings containing either an infinite element or a projective minimal left (right) ideal, showing, respectively, that semirings of those classes are not perfect and that the concepts of "mono-flatness" and "flatness" for semimodules over semirings of those classes are the same. Finally, we give a complete description of ideal-simple, artinian additively idempotent chain semirings, as well as of congruence-simple, lattice-ordered semirings.
Ore extensions of quasitriangular Hopf group coalgebras
Authors: Lu Daowei , Wang Dingguo
Published: December 2013

In this paper, we mainly consider some special Ore extension of quasitriangular Hopf group coalgebra, and give the necessary and sufficient conditions when the Ore extension of quasitriangular Hopf group coalgebras will preserve the same quasitriangular structure. Furthermore, in the two examples given at the end, we construct new solutions of Yang–Baxter equation of Hopf group coalgebras version.
Octonionic presentation for the lie group SL(2, 𝕆)
Authors: Veiro Jean Pierre
Published: December 2013

The purpose of this paper is to provide an octonionic description of the Lie group SL(2, 𝕆). The main result states that it can be obtained as a free group generated by invertible and determinant preserving transformations from 𝔥2(𝕆) onto itself. An interesting characterization is given for the generators of G2. Also, explicit isomorphisms are constructed between the Lie algebras 𝔰𝔩(2, 𝕂), for 𝕂 = ℝ, ℂ, ℍ, 𝕆, and their corresponding Lorentz algebras.
Some loci related to Cohen–Macaulayness
Authors: Nga Nguyen Thi Kieu
Published: December 2013

Let (R, 𝔪) be a Noetherian local ring and M a finitely generated R-module. The pseudo Cohen–Macaulayness (respectively, generalized Cohen–Macaulayness) was introduced by Cuong–Nhan [Pseudo Cohen–Macaulay and pseudo generalized Cohen–Macaulay modules, J. Algebra267 (2003) 156–177] as an extension of the Cohen–Macaulayness (respectively, generalized Cohen–Macaulayness). In this paper, we describe the pseudo Cohen–Macaulay (pseudo CM) locus and pseudo generalized Cohen–Macaulay (pseudo generalized CM) locus of M. We also study the non-Cohen–Macaulay locus and the non-generalized Cohen–Macaulay locus of the canonical module K(M) of M in case where R is a quotient of a Gorenstein local ring.
On F-Gorenstein dimensions
Authors: Tang Xi
Published: December 2013

Over an artin algebra Λ, for an additive subbifunctor F of [Formula: see text] with enough projectives and injectives, we introduce F-Gorenstein dimensions in this paper. The new relative dimensions are useful to characterize F-Gorenstein algebras and F-self-injective algebras. In addition, with the aid of F-Gorenstein dimensions, we obtain an equivalent condition for the finitistic dimension conjecture to hold, that is, fin.dim Λ < ∞ for all artin algebras Λ if and only if rel.fin.Gdim F Λ < ∞ for all artin algebras Λ.