bluuebunny/crossref_metadata_2025 huggingface dataset:
In situ
analysis of flow dynamics and deformation fields in cutting and sliding of metals
Authors: Guo Yang , Compton W. Dale , Chandrasekar Srinivasan
Published: May 2015

The flow dynamics, deformation fields and chip-particle formation in cutting and sliding of metals are analysed,
in situ
, using high-speed imaging and particle image velocimetry. The model system is a brass workpiece loaded against a wedge indenter at low speeds. At large negative rake angles, the flow is steady with a prow of material forming ahead of the indenter. There is no material removal and a uniformly strained layer develops on the workpiece surface—the pure sliding regime. When the rake angle is less negative, the flow becomes unsteady, triggered by formation of a crack on the prow free surface and material removal ensuing—the cutting regime. The strain on the prow surface at crack initiation is found to be constant. Chip morphologies, such as discrete particle, segmented chip and continuous chip with mesoscale roughness, are shown to arise from a universal mechanism involving propagation of the prow crack, but to different distances towards the indenter tip. The simple shear deformation in continuous chip formation shows small-angle oscillations also linked to the prow crack. Implications for material removal processes and ductile failure are discussed.
Extant primitively segmented spiders have recently diversified from an ancient lineage
Authors: Xu Xin , Liu Fengxiang , Cheng Ren-Chung , Chen Jian , Xu Xiang , Zhang Zhisheng , Ono Hirotsugu , Pham Dinh Sac , Norma-Rashid Y. , Arnedo Miquel A. , Kuntner Matjaž , Li Daiqin
Published: May 2015

Living fossils are lineages that have retained plesiomorphic traits through long time periods. It is expected that such lineages have both originated and diversified long ago. Such expectations have recently been challenged in some textbook examples of living fossils, notably in extant cycads and coelacanths. Using a phylogenetic approach, we tested the patterns of the origin and diversification of liphistiid spiders, a clade of spiders considered to be living fossils due to their retention of arachnid plesiomorphies and their exclusive grouping in Mesothelae, an ancient clade sister to all modern spiders. Facilitated by original sampling throughout their Asian range, we here provide the phylogenetic framework necessary for reconstructing liphistiid biogeographic history. All phylogenetic analyses support the monophyly of Liphistiidae and of eight genera. As the fossil evidence supports a Carboniferous Euramerican origin of Mesothelae, our dating analyses postulate a long eastward over-land dispersal towards the Asian origin of Liphistiidae during the Palaeogene (39–58 Ma). Contrary to expectations, diversification within extant liphistiid genera is relatively recent, in the Neogene and Late Palaeogene (4–24 Ma). While no over-water dispersal events are needed to explain their evolutionary history, the history of liphistiid spiders has the potential to play prominently in vicariant biogeographic studies.
Epidemic predictions in an imperfect world: modelling disease spread with partial data
Authors: Dawson Peter M. , Werkman Marleen , Brooks-Pollock Ellen , Tildesley Michael J.
Published: May 2015

‘Big-data’ epidemic models are being increasingly used to influence government policy to help with control and eradication of infectious diseases. In the case of livestock, detailed movement records have been used to parametrize realistic transmission models. While livestock movement data are readily available in the UK and other countries in the EU, in many countries around the world, such detailed data are not available. By using a comprehensive database of the UK cattle trade network, we implement various sampling strategies to determine the quantity of network data required to give accurate epidemiological predictions. It is found that by targeting nodes with the highest number of movements, accurate predictions on the size and spatial spread of epidemics can be made. This work has implications for countries such as the USA, where access to data is limited, and developing countries that may lack the resources to collect a full dataset on livestock movements.
Acetoanaerobium pronyense sp. nov., an anaerobic alkaliphilic bacterium isolated from a carbonate chimney of the Prony Hydrothermal Field (New Caledonia)
Authors: Bes Méline , Merrouch Mériem , Joseph Manon , Quéméneur Marianne , Payri Claude , Pelletier Bernard , Ollivier Bernard , Fardeau Marie-Laure , Erauso Gaël , Postec Anne
Published: May 2015

A novel anaerobic bacterial strain, ST07-YET, was isolated from a carbonate chimney of the Prony Hydrothermal Field (PHF) in New Caledonia. Cells were Gram-stain-positive, straight rods (0.7–0.8 × 3.0–5.0 μm) and motile by means of lateral flagella. Strain ST07-YET was mesophilic (optimum 35 °C), moderately alkaliphilic and halotolerant (optimum pH 8.7 and 5 g l− 1 NaCl). Elemental sulfur, sulfate, thiosulfate, sulfite, nitrate and nitrite were not used as terminal electron acceptors. Yeast extract, peptone, tryptone, Casamino acids, crotonate, pyruvate, galactose, maltose, sucrose, ribose, trehalose and glucose were used as carbon sources. Glucose fermentation led to acetate, H2 and CO2 formation. Arginine, serine, histidine, lysine, methionine and cysteine improved growth, but the Stickland reaction was negative for the combinations of amino acids tested. The major metabolic products from yeast extract fermentation were H2, CO2, acetate, butyrate, isobutyrate, isovalerate and propionate. The predominant cellular fatty acids were C16 
: 
0, C16 
: 
1
cis9, C14 
: 
0 and C16 
: 
1
cis7 (>5 % of total fatty acids). The G+C content of the genomic DNA was 32.9 mol%. Phylogenetic analysis revealed that strain ST07-YET was most closely related to Clostridium sticklandii DSM 519T and Acetoanaerobium noterae NOT-3T (96.7 % and 96.8 % 16S rRNA gene sequence similarity, respectively). On the basis of phylogenetic, chemotaxonomic and physiological properties, strain ST07-YET is proposed to represent a novel species of the genus Acetoanaerobium (order Clostridiales, phylum Firmicutes) with the name Acetoanaerobium pronyense sp. nov. The type strain is ST07-YET ( = DSM 27512T = JCM 19400T).
Negative Niche Construction Favors the Evolution of Cooperation
Authors: Connelly Brian D. , Dickinson Katherine J. , Hammarlund Sarah P. , Kerr Benjamin
Published: May 2015

By benefitting others at a cost to themselves, cooperators face an ever present threat from defectors—individuals that avail themselves of the cooperative benefit without contributing. A longstanding challenge to evolutionary biology is to understand the mechanisms that support the many instances of cooperation that nevertheless exist. Hammarlund et al. recently demonstrated that cooperation can persist by hitchhiking along with beneficial non-social adaptations. Importantly, cooperators play an active role in this process. In spatially-structured environments, clustered cooperator populations reach greater densities, which creates more mutational opportunities to gain beneficial non-social adaptations. Cooperation rises in abundance by association with these adaptations. However, once adaptive opportunities have been exhausted, the ride abruptly ends as cooperators are displaced by adapted defectors. Using an agent-based model, we demonstrate that the selective feedback that is created as populations construct their local niches can maintain cooperation indefinitely. This cooperator success depends specifically on negative niche construction, which acts as a perpetual source of adaptive opportunities. As populations adapt, they alter their environment in ways that reveal additional opportunities for adaptation. Despite being independent of niche construction in our model, cooperation feeds this cycle. By reaching larger densities, populations of cooperators are better able to adapt to changes in their constructed niche and successfully respond to the constant threat posed by defectors. We relate these findings to previous studies from the niche construction literature and discuss how this model could be extended to provide a greater understanding of how cooperation evolves in the complex environments in which it is found.
Polymorphism of NaVO2F2: aP21/csuperstructure with pseudosymmetry ofP21/min the subcell
Authors: Yu Zi-Qun , Wang Jing-Quan , Huang Ya-Xi , Botis Sanda M. , Pan Yuanming , Mi Jin-Xiao
Published: May 2015

The ADDSYM routine in the programPLATON[Spek (2015).Acta Cryst.C71, 9–18] has helped researchers to avoid structures of (metal–)organic compounds being reported in an unnecessarily low symmetry space group. However, determination of the correct space group may get more complicated in cases of pseudosymmetric inorganic compounds. One example is NaVO2F2, which was reported [Crosnier-Lopezet al.(1994).Eur. J. Solid State Inorg. Chem.31, 957–965] in the acentric space groupP21based on properties but flagged by ADDSYM as (pseudo)centrosymmetricP21/mwithin default distance tolerances. Herein a systematic investigation reveals that NaVO2F2exists in at least four polymorphs:P21, (I),P21/m, (II),P21/c, (III), and one or more low-temperature ones. The new centrosymmetric modification, (III), with the space groupP21/chas a similar atomic packing geometry to phase (I), except for having a doubledcaxis. The double-cell of phase (III) arises from atomic shifts from the glide planecat (x, 1/4,z). With increasing temperature, the number of observed reflections decreases. The oddlreflections gradually become weaker and, correspondingly, all atoms shift towards the glide plane, resulting in a gradual second-order transformation of (III) into high-temperature phase (II) (P21/m) at below 493 K. At least one first-order enantiotropic phase transition was observed below 139 K from both the single-crystal X-ray diffraction and the differential scanning calorimetry analyses. Periodic first-principles calculations within density functional theory show that bothP21/csuperstructure (III) andP21substructure (I) are more stable thanP21/mstructure (II), and thatP21/csuperstructure (III) is more stable thatP21substructure (I).
Iron superoxide dismutases in eukaryotic pathogens: new insights from Apicomplexa andTrypanosomastructures
Authors: Phan Isabelle Q. H. , Davies Douglas R. , Moretti Nilmar Silvio , Shanmugam Dhanasekaran , Cestari Igor , Anupama Atashi , Fairman James W. , Edwards Thomas E. , Stuart Kenneth , Schenkman Sergio , Myler Peter J.
Published: May 2015

Prior studies have highlighted the potential of superoxide dismutases as drug targets in eukaryotic pathogens. This report presents the structures of three iron-dependent superoxide dismutases (FeSODs) fromTrypanosoma cruzi,Leishmania majorandBabesia bovis. Comparison with existing structures fromPlasmodiumand other trypanosome isoforms shows a very conserved overall fold with subtle differences. In particular, structural data suggest thatB. bovisFeSOD may display similar resistance to peroxynitrite-mediated inactivationviaan intramolecular electron-transfer pathway as previously described inT. cruziFeSOD isoform B, thus providing valuable information for structure-based drug design. Furthermore, lysine-acetylation results inT. cruziindicate that acetylation occurs at a position close to that responsible for the regulation of acetylation-mediated activity in the human enzyme.
Analytical optimization of litz-wire windings independent of porosity factor
Authors: Wojda Rafal P. , Kazimierczuk Marian K.
Published: May 2015

Purpose

– The purpose of this paper is threefold. First, an analytical model based on one-dimensional Dowell’s equation for computing ac-to-dc winding resistance ratio FR of litz wire is presented. The model takes into account proximity effect within the bundle and between bundle layers as well as the skin effect. Second, low- and medium-frequency approximation of Dowell’s equation for the litz-wire winding is derived. Third, a derivation of an analytical equation is given for the optimum strand diameter of the litz-wire winding independent on the porosity factor.

Design/methodology/approach

– The methodology is as follows. First, the model of the litz-wire bundle is assumed to be a square shape. Than the effective number of layers in the litz wire bundle is derived. Second, the litz-wire winding is presented and an analytical equation for the winding resistance is derived. Third, analytical optimization of the strand diameter in the litz-wire winding is independent on the porosity factor performed, where the strand diameter is independent on the porosity factor. The boundary frequency between the low-frequency and the medium-frequency ranges for both solid-round-wire and litz-wire windings are derived. Hence, useful frequency range of both windings can be determined and compared.

Findings

– Closed form analytical equations for the optimum strand diameter independent of the porosity factor are derived. It has been shown that the ac-to-dc winding resistance ratio of the litz-wire winding for the optimum strand diameter is equal to 1.5. Moreover, it has been shown that litz-wire winding is better than the solid-round-wire winding only in specific frequency range. At very high frequencies the litz-wire winding ac resistance becomes much greater than the solid-round-wire winding due to proximity effect between the strands in the litz-wire bundle. The accuracy of the derived equations is experimentally verified.

Research limitations/implications

– Derived equations takes into account the losses due to induced eddy-currents caused by the applied current. Equations does not take into account the losses caused by the fringing flux, curvature, edge and end winding effects.

Originality/value

– This paper presents derivations of the closed-form analytical equations for the optimum bare strand diameter of the litz-wire winding independent on the porosity factor. Significant advantage of derived equations is their simplicity and easy to use for the inductor designers.
Model calibration of non-ideal lowpass filter in modulated wideband converter for compressive sampling
Authors: Zhao Yijiu , Wang Houjun , Dai Zhijian
Published: May 2015

Purpose

– The purpose of this paper is to present a model calibration technique for modulated wideband converter (MWC) with non-ideal lowpass filter. Without making any change to the system architecture, at the cost of a moderate oversampling, the calibrated system can perform as the system with ideal lowpass filter.

Design/methodology/approach

– A known test sparse signal is used to approximate the finite impulse response (FIR) of the practical non-ideal lowpass filter. Based on the approximated FIR filter, a digital compensation filter is designed to calibrate the practical filter. The calibrated filter can meet the perfect reconstruction condition. The non-ideal sub-Nyquist samples are filtered by a compensation filter.

Findings

– Experimental results indicate that, by calibrating the MWC with the proposed algorithm, the impaction of non-ideal lowpass filter could be avoided. The performance of signal reconstruction could be improved significantly.

Originality/value

– Without making any change to the MWC architecture, the proposed algorithm can calibrated the non-ideal lowpass filter. By filtering the non-ideal sub-Nyquist samples with the designed compensation filter, the original signal could be reconstructed with high accuracy.
An improved criterion for peak-to-peak realization of direct-form interfered digital filters employing saturation nonlinearities
Authors: Kokil Priyanka , Shinde Swapnil Sadashiv
Published: May 2015

Purpose

– The purpose of this paper is to present a criterion for global asymptotic stability of state-space direct-form digital filters employing saturation arithmetic.

Design/methodology/approach

– An elegant use of inducedl∞approach (also known as a peak-to-peak approach) is made to develop a criterion for the overflow stability of state-space direct-form digital filters.

Findings

– The criterion not only guarantees asymptotic stability but also reduces the effect of external interference. The presented method yields better interference attenuation level as compared to a recently reported method. Numerical examples are given to illustrate the effectiveness of the proposed method.

Practical implications

– Digital filters are important dynamical systems in signal processing which are used for the processing of discrete signals. During the implementation of higher-order digital filter in hardware or software, introduction of external interference is unavoidable. Therefore, stability analysis of digital filters in the presence of external interference is of much practical importance.

Originality/value

– The main result of the paper is reported for the first time and it is useful to establish the asymptotic stability of digital filters in the presence of external disturbances.
Capital budgeting practices: evidence from Sri Lanka
Authors: Nurullah Mohamed , Kengatharan Lingesiya
Published: May 2015

Purpose

– The purpose of this paper is to investigate prevailing capital budgeting practices in Sri Lankan listed companies.

Design/methodology/approach

– A comprehensive primary survey was conducted of 32 out of 46 chief financial officers (CFOs) of manufacturing and trading companies listed on the Colombo Stock Exchange in Sri Lanka. Garnered data were then analyzed using appropriate statistical techniques.

Findings

– The results revealed that net present value (NPV) was the most preferred capital budgeting method, followed closely by payback (PB) and internal rate of return (IRR). Similarly, sensitivity analysis was regarded as the dominant capital budgeting tool for incorporating risk and the widely used method for calculating cost of capital was the weighted average cost of capital. Moreover, results revealed that size of the capital budget affects the use of the capital budgeting methods (NPV, IRR and PB) and incorporating risk tool (sensitivity analysis and simulation). Further, results revealed that CFOs had higher educational qualification were preferred to use sophisticated capital budgeting practices dominantly NPV, IRR and incorporating risk tool of sensitivity analysis although they were found to be reluctant in use of accounting rate of return. In a similar vein CFOs with higher experience were preferred using IRR and sensitivity analysis.

Originality/value

– This study contributed to academics, practitioners, policy makers and stakeholders of the company. Moreover, this research has proffered a more reliable and comprehensive analysis of capital budgeting practices in Sri Lankan listed manufacturing and trading firms. Since Sri Lanka is an unexplored country on capital budgeting practices, this research was originally contributed to the extant literature per se.
Behavior of Indian sectoral stock price indices in the post subprime crisis period
Authors: Vardhan Harsh , Sinha Pankaj , Vij Madhu
Published: May 2015

Purpose

– The purpose of this paper is to demonstrate importance of usage of sector indices which provides insight for sector specific investment strategies and direction for suitable policy formulation for the Indian industry. It investigates long run, short run and causality relationships between eight identified sector indices and Sensex for the post subprime period.

Design/methodology/approach

– The study uses Vector Error Correction Model (VECM) for econometric analysis. It employs Generalized Impulse Response and Variance Decomposition analysis for developed multivariate framework in order to provide information about precise interplay of the sector indices.

Findings

– Long-term relationships between sector indices were determined by the usage of VECM indicating minimal benefits from diversifying investments to different sectors. Limited lead – lag short run relationships between sector indices were observed. Banking index played a predominant and integrating role in moving other indices. During this period of recovery; most sectors were protected and provided marginally better returns due to robust Banking policy. Realty and Metal were other significant drivers influencing remaining sectors contemporaneously. The study for the post subprime crisis period helps to understand the importance and behavior of interrelated sector indices and Sensex in the dynamic economic environment.

Practical implications

– The study clearly provides direction for sector specific investment strategies and policy formulation.

Originality/value

– The study highlights utility and importance of usage of sector indices. No study using sector indices for the Indian economy have been done earlier employing VAR for the post subprime crisis period.
Inductive Praxis and Management Research: Towards a Reflexive Framework
Authors: Johnson Phil , Duberley Joanne
Published: May 2015

This paper examines how induction legitimately varies according to the impact of different knowledge constituting philosophical assumptions. As a result of its prevalence in qualitative management research, the paper focuses on grounded theory and uses this as a vehicle to explore the key parameters of the philosophical diversity articulated in judgements around neutrality, description and theorization. A reflexive framework of inductive praxis is offered as a heuristic device for interrogating the choices evidently at play in the variable constitution of inductive management research. We indicate how there are multiple modes of engagement, each of which is legitimate within its own philosophical commitments. This implies the need for a more tolerant pluralistic stance in the evaluation of qualitative management research.
Capital Income Taxation Revisited: The Roles of Information Friction and External Finance
Authors: Ho Wai‐Hong , Wang Yong
Published: May 2015

This paper reexamines the classical issue of optimal taxation on capital income in an overlapping‐generations growth model where the risky capital‐producing projects are financed partially with external funds in the presence of costly state verification. In this context, we first show that the information friction creates standard credit market distortions that are exacerbated by both capital income taxation and external financing. We subsequently show from both growth and welfare perspectives that the optimal tax rate on capital income decreases with the severity of asymmetric information and the extent of external financing. Alternatively, our analysis suggests that the presence of informational friction in the credit market introduces a rationale for more conservative taxation on capital, especially when the need for external financing is high.
Indeterminacy with Progressive Taxation and Sector‐Specific Externalities
Authors: Guo Jang‐Ting , Harrison Sharon G.
Published: May 2015

This paper quantitatively examines the empirical plausibility of equilibrium indeterminacy and sunspot‐driven cyclical fluctuations in a real business cycle model with two distinct production sectors that yield consumption and investment goods, together with separable or non‐separable preferences. When calibrated to match the observed progressivity of the US federal individual income tax schedule, each version of our model economy exhibits an indeterminate steady state under empirically realistic combinations of the household's labour supply elasticity and the degree of productive externalities in the investment goods sector. Therefore, macroeconomic instability due to agents' self‐fulfilling expectations may, in fact, be a prevalent feature of the US economy.
Morbidity associated with episiotomy in vacuum delivery: a systematic review and meta‐analysis
Authors: Sagi‐Dain L , Sagi S
Published: May 2015

Background

The role of episiotomy in vacuum deliveries is controversial.

Objectives

To perform a meta‐analysis of the literature examining this subject.

Search strategy

The search was conducted in four databases.

Selection criteria

Two investigators independently selected original research examining the effects of episiotomy on any neonatal and maternal outcomes during vacuum delivery.

Data collection and analysis

The effect estimates were presented as odds ratios (ORs) with 95% confidence intervals (95% CIs).

Main results

Fifteen articles were included, encompassing a total of 350 764 vacuum deliveries. A non‐significant relationship was shown between mediolateral episiotomy and obstetric anal sphincter injuries (OASIS) in nulliparous women (OR 0.68, 95% CI 0.43–1.07; six studies), whereas an increased risk was demonstrated in parous women (OR 1.27, 95% CI 1.05–1.53; two reports). A higher risk of OASIS with median episiotomy use was shown in nulliparous (OR 5.11, 95% CI 3.23–8.08; two studies) as well as in parous (OR 89.4, 95% CI 11.8–677.1; one study) women. Lateral episiotomy was related to lower OASIS risk in nullipara (OR 0.59, 95% CI 0.49–0.70; single paper). Mediolateral episiotomy was linked to increased rates of postpartum haemorrhage (OR 1.82, 95% CI 1.16–2.86) and analgesia use (OR 2.10, 95% CI 1.39–3.17; two reports). Overall, the quality of evidence was rated as low to very low.

Author's conclusions

Mediolateral and median episiotomy in parous woman may increase the rate of OASIS at vacuum delivery, whereas lateral episiotomy in nulliparous women could be associated with a decreased risk of OASIS. The suboptimal quality of the available evidence necessitates high‐quality well‐designed randomised trials.

Tweetable abstract

Episiotomy in vacuum delivery does not appear to be of benefit, and might even increase maternal morbidity.
The development and application of a multiplex short tandem repeat (STR) system for identifying subspecies, individuals and sex in tigers
Authors: ZOU Zheng‐Ting , UPHYRKINA Olga V. , FOMENKO Pavel , LUO Shu‐Jin
Published: May 2015

Poaching and trans‐boundary trafficking of tigers and body parts are threatening the world's last remaining wild tigers. Development of an efficient molecular genetic assay for tracing the origins of confiscated specimens will assist in law enforcement and wildlife forensics for this iconic flagship species. We developed a multiplex genotyping system “tigrisPlex” to simultaneously assess 22 short tandem repeat (STR, or microsatellite) loci and a gender‐identifyingSRYgene, all amplified in 4 reactions using as little as 1 ng of template DNA. With DNA samples used for between‐run calibration, the system generates STR genotypes that are directly compatible with voucher tiger subspecies genetic profiles, hence making it possible to identify subspecies via bi‐parentally inherited markers. We applied “tigrisPlex” to 12 confiscated specimens from Russia and identified 6 individuals (3 females and 3 males), each represented by duplicated samples and all designated as Amur tigers (Panthera tigris altaica) with high confidence. This STR multiplex system can serve as an effective and versatile approach for genetic profiling of both wild and captive tigers as well as confiscated tiger products, fulfilling various conservation needs for identifying the origins of tiger samples.
A genomewide catalogue of single nucleotide polymorphisms in white‐beaked and Atlantic white‐sided dolphins
Authors: Fernández R. , Schubert M. , Vargas‐Velázquez A. M. , Brownlow A. , Víkingsson G. A. , Siebert U. , Jensen L. F. , Øien N. , Wall D. , Rogan E. , Mikkelsen B. , Dabin W. , Alfarhan A. H. , Alquraishi S. A. , Al‐Rasheid K. A. S. , Guillot G. , Orlando L.
Published: May 2015

The field of population genetics is rapidly moving into population genomics as the quantity of data generated by high‐throughput sequencing platforms increases. In this study, we used restriction‐site‐associated DNA sequencing (RADSeq) to recover genomewide genotypes from 70 white‐beaked (Lagenorhynchus albirostris) and 43 Atlantic white‐sided dolphins (L. acutus) gathered throughout their north‐east Atlantic distribution range. Both species are at a high risk of being negatively affected by climate change. Here, we provide a resource of 38 240 RAD‐tags and 52 981 nuclear SNPs shared between both species. We have estimated overall higher levels of nucleotide diversity in white‐sided (π = 0.0492 ± 0.0006%) than in white‐beaked dolphins (π = 0.0300 ± 0.0004%). White‐sided dolphins sampled in the Faroe Islands, belonging to two pods (N = 7 and N = 11), showed similar levels of diversity (π = 0.0317 ± 0.0007% and 0.0267 ± 0.0006%, respectively) compared to unrelated individuals of the same species sampled elsewhere (e.g. π = 0.0285 ± 0.0007% for 11 Scottish individuals). No evidence of higher levels of kinship within pods can be derived from our analyses. When identifying the most likely number of genetic clusters among our sample set, we obtained an estimate of two to four clusters, corresponding to both species and possibly, two further clusters within each species. A higher diversity and lower population structuring was encountered in white‐sided dolphins from the north‐east Atlantic, in line with their preference for pelagic waters, as opposed to white‐beaked dolphins that have a more patchy distribution, mainly across continental shelves.
In vitro biofilm development of Streptococcus pneumoniae and formation of choline‐binding protein–DNA complexes
Authors: Domenech Mirian , Ruiz Susana , Moscoso Miriam , García Ernesto
Published: May 2015

Extracellular deoxyribonucleic acid (eDNA) is an essential component of bacterial biofilm matrices, and is required in their formation and maintenance. Extracellular DNA binds to exopolysaccharides or extracellular proteins, affording biofilms greater structural integrity. Recently, we reported evidence of intercellular eDNA−LytC complexes in pneumococcal biofilms. The LytC lysozyme is a member of the choline‐binding family of proteins (CBPs) located on the pneumococcal surface. The present work shows that other CBPs, i.e. LytA, LytB, Pce, PspC and CbpF, which have a pI between 5 and 6, can bind DNA in vitro. This process requires the presence of divalent cations other than Mg2+. This DNA binding capacity of CBPs appears to be independent of their enzymatic activity and, at least in the case of LytA, does not require the choline‐binding domain characteristic of CBPs. Positively charged, surface‐exposed, 25 amino acid‐long peptides derived from the catalytic domain of LytB, were also found capable of DNA binding through electrostatic interactions. Confocal laser scanning microcopy revealed the existence of cell‐associated LytB−eDNA complexes in Streptococcus pneumoniae biofilms. These and other findings suggest that these surface‐located proteins of S. pneumoniae could play roles of varying importance in the colonization and/or invasion of human host where different environmental conditions exist.
Thin and thick layers of resin‐based sealer cement bonded to root dentine compared: Adhesive behaviour
Authors: Pane Epita S. , Palamara Joseph E.A. , Messer Harold H.
Published: May 2015

This study aims to evaluate tensile and shear bond strengths of one epoxy (AH) and two methacrylate resin‐based sealers (EZ and RS) in thin and thick layers bonded to root dentine. An alignment device was prepared for accurate positioning of 20 root dentine cylinders in a predefined gap of 0.1 or 1 mm. Sealer was placed in the interface. Bond strength tests were conducted. Mode of failures and representative surfaces were evaluated. Data were analysed using anova and post‐hoc tests, with P < 0.05. The thick layer of sealer produced higher bond strength, except for the shear bond strength of EZ. Significant differences between thin and thick layers were found only in tensile bond strengths of AH and RS. Mixed type of failure was constantly found with all sealers. Bond strengths of thick layers of resin‐based sealers to root dentine tended to be higher than with thin layers.
Pathological and problem gambling in substance use treatment: Results from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC)
Authors: Cowlishaw Sean , Hakes Jahn K
Published: May 2015

Background and Objectives

Pathological and problem gambling may be common yet frequently undetected conditions in substance use treatment. This paper reports findings on the prevalence of gambling comorbidities in these clinical contexts that are generalizable across regions and settings. It indicates the implications of such conditions for treatment of substance use problems.

Methods

A U.S. representative sample of n = 402 patients reporting past‐year treatment for substance use problems was derived from wave 1 and 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Weighted prevalence estimates were produced and regression analyses used to examine correlates of gambling symptoms.

Results

Rates of lifetime pathological gambling (5+ DSM‐IV symptoms) and problem gambling (3+ DSM‐IV symptoms) were 4.3% (s.e. = 1.3%) and 7.2% (s.e. = 1.6%), respectively. Lifetime gambling symptoms were associated with Axis II disorders, but no Axis I diagnoses. There was limited evidence of associations with substance usage, mental or physical health and medical utilization. There were associations with financial crises and relationship breakdown, during and after treatment.

Conclusions and Scientific Significance

Gambling problems are elevated in substance use treatment but may be less common than previously thought; when considered nationally and across clinical settings. They may have modest associations with clinical characteristics given high levels of psychiatric severity that characterise treatment seeking samples overall. Notwithstanding, the results suggest that gambling comorbidities should be standard considerations in substance use treatment. They may signal complex conditions characterised by pervasive underlying psychopathology, and psychosocial difficulties that accumulate over time. (Am J Addict 2015;24:467 –474)
Who Overreacts to Overnight News?: Empirical Evidence from the Korean Stock Market
Authors: Kwon Enjung , Eom Young Ho , Jang Woon Wook , Hahn Jaehoon
Published: May 2015

We investigate whether the pattern of intraday return reversal in Korea, recently found to be significant only when the previous day's United States stock market movements are relatively large, is due to overreaction of investors. We estimate a partial adjustment model modified to distinguish price reaction at the open and at the close, and the results indicate that the Korean stock market tends to overreact at the open and underreact at the close. Furthermore, our evidence suggests that foreign investors' trading behavior contributes to overreaction at the open, while individual investors' trading behavior contributes to return reversal during the trading day.
Fire effects on invasive and native warm‐season grass species in a North American grassland at a time of extreme drought
Authors: Havill Scott , Schwinning Susanne , Lyons Kelly G.
Published: May 2015

Question

Can the timing of cutting or burning be used to selectively damage an invasive C4 grass species while limiting collateral damage to dominant native C4 grass species in a grassland community?

Location

A medium to short grass prairie in central Texas, US.

Methods

We conducted six cut and burn trials between June 2011 and January 2012 during an exceptional drought year. Target species were the native, perennial, C4 grass Schizachyrium scoparium (little bluestem) and the introduced, perennial, C4 grass Bothriochloa ischaemum (yellow bluestem). Burn trials were conducted inside a steel barrel using standardized fuel loads. To assess recovery, we counted the first cohort of new tillers that emerged after treatment and tillers that grew in the subsequent spring. We also recorded phenological status, meteorological variables and burn temperatures to determine if tiller recovery was predictable.

Results

Bothriochloa ischaemum responded more negatively to burning than to cutting, but these treatments were no different for S. scoparium. Both species produced the smallest number of tillers after the summer burns, and the burn date × species interaction was insignificant. On average, peak fire temperature inside tussocks was 100 °C higher in B. ischaemum than in S. scoparium. Judging from the reduction in tiller densities in undisturbed plots from spring 2011 to spring 2012, B. ischaemum was also more sensitive to drought. Multivariate models were significant and related burn recovery to peak fire temperature, among other factors, and recovery from cutting to ambient temperature on the day of cutting. In B. ischaemum, plants with higher investment in early reproductive growth suffered more burn damage.

Conclusions

We identified no optimal burn time that maximized discrimination between the two species. Nonetheless, the invasive species was more sensitive to both drought and fire, possibly due to higher heat exposure of growing points. Thus, burning during the summer of a drought year may constitute the sought‐after treatment that selectively favours native species. Ultimately, successful management will involve fuel and temperature management combined with assessment of the relative phenologies of the target species prior to burning. This study suggests that a hot fire at a time when the invasive species has a larger investment in early reproductive growth will provide the best control.
Chronology and palaeoenvironmental implications of the ice‐wedge pseudomorphs and composite‐wedge casts on the Magdalen Islands (eastern Canada)
Authors: Rémillard Audrey M. , Hétu Bernard , Bernatchez Pascal , Buylaert Jan‐Pieter , Murray Andrew S. , St‐Onge Guillaume , Geach Martin
Published: May 2015

The Magdalen Islands are a valuable terrestrial record, evidencing the complex glacial and periglacial history of the Gulf of St. Lawrence. Thirteen structures interpreted as ice‐wedge pseudomorphs or composite‐wedge casts were observed at four sites on the southern Magdalen Islands and testify to the former presence of permafrost under periglacial conditions. These features truncate Carboniferous sandstone or Last Glacial Maximum (LGM) glacial and glaciomarine diamicts, both overlain by subtidal or coastal units. Six optically stimulated luminescence (OSL) and four radiocarbon ages were obtained from both host and infilled sedimentary units. These ages provide the first absolute chronological data on these structures, shedding new light on the relationships between glacial and periglacial phases. Our chronostratigraphic data suggest that, after the deglaciation and the emersion of the archipelago, thermal contraction cracks grew during the cold period of the Younger Dryas (11–10 ka; 12.9–11.5 cal. ka BP). The Younger Dryas, which is well documented in the Maritime Provinces of Canada, occurred after a pedogenesis phase associated with the Allerød warm period evidenced by the well‐developed palaeopodzol ubiquitous on the Magdalen Islands.
Do food deserts exist in Calgary, Canada?
Authors: Lu Wei , Qiu Feng
Published: May 2015

A significant amount of research has examined supermarket accessibility, and food deserts have been identified among high‐need residents. However, little research has explored the changes that occur in terms of access to healthy food when taking farmers' markets into consideration. Furthermore, few researchers have emphasized communities with large populations of children and seniors. This study investigated the accessibility of supermarkets and farmers' markets in the city of Calgary, Canada. Two communities with proportionately large populations of children and seniors coupled with low income levels and limited access to healthy food sources, were identified as food deserts. The results also suggested that farmers' markets provide surrounding neighbourhoods with significant benefits, even though the overall alleviating effects on the lack of access to healthy food are limited.
Syntheses, Cholinesterases Inhibition, and Molecular Docking Studies of Pyrido[2,3‐b]pyrazine Derivatives
Authors: Hameed Abdul , Zehra Syeda T. , Shah Syed J. A. , Khan Khalid M. , Alharthy Rima D. , Furtmann Norbert , Bajorath Jürgen , Tahir Muhammad N. , Iqbal Jamshed
Published: May 2015

Cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), have a role in cholinergic deficit which evidently leads to Alzheimer's disease (AD). Inhibition of cholinesterases with small molecules is an attractive strategy in AD therapy. This study demonstrates synthesis of pyrido[2,3‐b]pyrazines (6a‐6q) series, their inhibitory activities against both cholinesterases, AChE and BChE, and molecular docking studies. The bioactivities data of pyrido[2,3‐b]pyrazines showed 3‐(3′‐nitrophenyl)pyrido[2,3‐b]pyrazine 6n a potent dual inhibitor among the series against both AChE and BChE with IC50 values of 0.466 ± 0.121 and 1.89 ± 0.05 μm, respectively. The analogues 3‐(3′‐methylphenyl)pyrido[2,3‐b]pyrazine 6c and 3‐(3′‐fluorophenyl)pyrido[2,3‐b]pyrazine 6f were found to be selective inhibition for BChE with IC50 values of 0.583 ± 0.052 μm and AChE with IC50 value of 0.899 ± 0.10 μm, respectively. Molecular docking studies of the active compounds suggested the putative binding modes with cholinesterases. The potent compounds among the series could potentially serves as good leads for the development of new cholinesterase inhibitors.
Eating marshmallows reduces ileostomy output: a randomized crossover trial
Authors: Clarebrough E. , Guest G. , Stupart D.
Published: May 2015

Aim

Anecdotally, many ostomates believe that eating marshmallows can reduce ileostomy effluent. There is a plausible mechanism for this, as the gelatine contained in marshmallows may thicken small bowel fluid, but there is currently no evidence that this is effective.

Method

This was a randomized crossover trial. Adult patients with well‐established ileostomies were included. Ileostomy output was measured for 1 week during which three marshmallows were consumed three times daily, and for one control week where marshmallows were not eaten. There was a 2‐day washout period. Patients were randomly allocated to whether the control or intervention week occurred first. In addition, a questionnaire was administered regarding patient's subjective experience of their ileostomy function.

Results

Thirty‐one participants were recruited; 28 completed the study. There was a median reduction in ileostomy output volume of 75 ml per day during the study period (P = 0.0054, 95% confidence interval 23.4–678.3) compared with the control week. Twenty of 28 subjects (71%) experienced a reduction in their ileostomy output, two had no change and six reported an increase. During the study period, participants reported fewer ileostomy bag changes (median five per day vs six in the control period, P = 0.0255). Twenty of 28 (71%) reported that the ileostomy effluent was thicker during the study week (P = 0.023). Overall 19 (68%) participants stated they would use marshmallows in the future if they wanted to reduce or thicken their ileostomy output.

Conclusion

Eating marshmallows leads to a small but statistically significant reduction in ileostomy output.
Long‐term outcome of prucalopride for chronic constipation: a single‐centre study
Authors: Dhruva Rao P. K. , Lewis M. , Peiris S. P. M. , Shah P. R. , Haray P. N.
Published: May 2015

Aim

Newer 5‐hydroxytryptamine agonists, such as prucalopride, have been demonstrated to be effective in the short term for treatment of chronic constipation. To date, few studies have investigated their medium‐ and long‐term effectiveness.

Method

An analysis was carried out of a prospectively maintained database of all patients started on prucalopride for chronic constipation between April 2011 and April 2014. Cleveland Clinic Constipation Score (CCCS) questionnaires were administered before starting treatment with prucalopride and at the first follow‐up visit to assess change in CCCS scores in 50 randomly selected patients.

Results

A total of 155 patients (median age: 47 years; seven men) were started on prucalopride in this period. Of these, 16 (10%) had slow‐transit constipation, 31 (20%) had obstructive defaecation syndrome and 30 (19%) had a combination of both. Of these 155 patients, 78% patients were on three or more laxatives at the time of starting prucalopride. Patients were started on 1 mg or 2 mg according to their age. The median follow‐up period was 24 (range: 4–40) months. At the first follow‐up visit, 106 (68%) patients reported good symptomatic improvement, whereas the remainder had no response. Third of initial responders showed decreased efficacy after a median duration of 6 months and needed regular laxatives/irrigation. Of the 50 patients who filled in the CCCS questionnaires (15 patients were nonresponders), 32 (64%) reported improved scores with a median improvement of two points per criterion.

Conclusion

This study provides evidence that prolonged use of prucalopride is effective in achieving a sustained benefit in the majority of patients.
Anetoderma arising in Reed syndrome: a case report and review of the literature
Authors: Velez Moises J. , Mesinkovska Natasha , Bergfeld Wilma F.
Published: May 2015

Anetoderma is a cutaneous disorder characterized by loss of dermal elastic tissue resulting in papules from herniation of subcutaneous tissue or circumscribed areas of atrophic, wrinkled skin. Familial leiomyomatosis cutis et uteri (Reed syndrome) is an autosomal dominant disorder characterized by cutaneous and uterine leiomyomas. We report a 23‐year‐old male with Reed syndrome who presented with asymptomatic pearly white, atrophic, flaccid papules on the upper back and shoulder that depressed when palpated. Pathologic examination showed an unremarkable epidermis and central loss of dermal elastin, bordered by clumped elastin, as revealed with an elastin stain. The correlation of clinical and pathologic findings indicated a diagnosis of anetoderma arising in a patient with Reed syndrome.
Cerebral palsy research funding from the National Institutes of Health, 2001 to 2013
Authors: Wu Yvonne W , Mehravari Alison S , Numis Adam L , Gross Paul
Published: May 2015

Aim

Cerebral palsy (CP) is a poorly understood disorder with no cure. We determined the landscape of National Institutes of Health (NIH) funding for CP‐related research.

Method

We searched NIH databases Research Portfolio Online Reporting Tools Expenditures and Results, and Research, Condition, and Disease Categorization for keywords ‘cerebral palsy’ among all NIH‐funded studies, 2001 to 2013. We classified grants by type and area of study.

Results

NIH funding, averaging $30 million per year, supported clinical ($215 million), basic ($187 million), and translational ($26.3 million) CP‐related research. Clinical intervention studies comprised 19% of funding, and focused on treatments ($60.3 million), early parent intervention ($2.7 million), and CP prevention ($2.5 million). Among grants that specified gestational age, more funds were devoted to preterm ($166 million) than term infants ($15 million). CP in adulthood was the main focus of 4% of all funding. Annual NIH funding for CP increased steadily over the study period from $3.6 to $66.7 million. However, funding for clinical intervention studies peaked in 2008, and has since decreased.

Interpretation

Additional research funds are needed to improve the treatment and prevention of CP. Topics that have been relatively underfunded include clinical interventions, prevention, and term infants and adults with CP.