bluuebunny/crossref_metadata_2025 huggingface dataset:
Bias‐reduced marginal Akaike information criteria based on a Monte Carlo method for linear mixed‐effects models
Authors: Sakamoto Wataru
Published: May 2018

In linear mixed‐effects (LME) models, if a fitted model has more random‐effect terms than the true model, a regularity condition required in the asymptotic theory may not hold. In such cases, the marginal Akaike information criterion (AIC) is positively biased for (−2) times the expected log‐likelihood. The asymptotic bias of the maximum log‐likelihood as an estimator of the expected log‐likelihood is evaluated for LME models with balanced design in the context of parameter‐constrained models. Moreover, bias‐reduced marginal AICs for LME models based on a Monte Carlo method are proposed. The performance of the proposed criteria is compared with existing criteria by using example data and by a simulation study. It was found that the bias of the proposed criteria was smaller than that of the existing marginal AIC when a larger model was fitted and that the probability of choosing a smaller model incorrectly was decreased.
Relationship between duration of practice and soil chemical characteristics of upland fields under organic farming in Japan
Authors: Nakagawa S. , Kuwamura T. , Yamada K. , Yamamoto H. , Hatakenaka K. , Yonekura K.
Published: May 2018

Relationships between the duration (in years) of practice and soil (0–30‐cm layer) chemical properties of 189 upland fields under organic farming in Japan were investigated. Electrical conductivity and available phosphorus (P), nitrate nitrogen (NO3‐N), Cl− and sulphate sulphur (SO4‐S) decreased and became constant with increasing duration of practice. This was probably because of the absence of mineral fertilizers and the reduced use of animal‐based fertilizers as the duration of organic farming increased.
Academic ability and teamworking in medical students
Authors: Parker Rupert , Hodierne Laurence , Anderson Elizabeth S , Davies Robert SM , Elloy Marianne
Published: May 2018

Background

Teamworking is an essential skill for a doctor to develop in order to work effectively, and is required in the UK as part of the General Medical Council (GMC) Good Medical Practice guidance. Assessment of teamwork may be difficult, however, with medical school assessments being more commonly focused on knowledge and individual skills. We aim to explore the link between academic ability as measured at final medical examinations and teamworking.

Methods

All final‐year medical students were asked to attend a simulation session in an immersive 22‐bed simulated ward, which used a combination of patient simulators and high‐fidelity manikin simulators, with nursing and telephone support. Students were split into separate groups stratified by performance in final‐year assessments or in groups with mixed performance. Students were observed in real time by faculty staff and assessed with the individual Teamwork Observation and Feedback Tool (iTOFT), around which the debriefing was centred.

Assessment of teamwork may be difficult

Results

The performance of 119 students in simulation was assessed, and groups with a mix of academic performance showed significantly greater teamworking ability as measured with the iTOFT as compared with those stratified by performance (p = 0.045). Final assessment at medical school was shown to be a poor predictor of teamworking ability: those who performed best at assessment seemed to underperform in teamworking.

Discussion

The simulated‐ward learning activity received positive feedback, although the mix of patient simulators and high‐fidelity manikins proved a challenge to some students. Medical school assessments appear to be inadequate in the assessment of teamworking ability, with change needed in future to ensure that this and other non‐technical skills are assessed.
Expression of TRPV1 channels by Cajal‐Retzius cells and layer‐specific modulation of synaptic transmission by capsaicin in the mouse hippocampus
Authors: Anstötz Max , Lee Sun Kyong , Maccaferri Gianmaria
Published: May 2018

Key points

By taking advantage of calcium imaging and electrophysiology, we provide direct pharmacological evidence for the functional expression of TRPV1 channels in hippocampal Cajal‐Retzius cells.

Application of the TRPV1 activator capsaicin powerfully enhances spontaneous synaptic transmission in the hippocampal layers that are innervated by the axons of Cajal‐Retzius cells.

Capsaicin‐triggered calcium responses and membrane currents in Cajal‐Retzius cells, as well as layer‐specific modulation of spontaneous synaptic transmission, are absent when the drug is applied to slices prepared from TRPV1−/−animals.

We discuss the implications of the functional expression of TRPV1 channels in Cajal‐Retzius cells and of the observed TRPV1‐dependent layer‐specific modulation of synaptic transmission for physiological and pathological network processing.

The vanilloid receptor TRPV1 forms complex polymodal channels that are expressed by sensory neurons and play a critical role in nociception. Their distribution pattern and functions in cortical circuits are, however, much less understood. Although TRPV1 reporter mice have suggested that, in the hippocampus, TRPV1 is predominantly expressed by Cajal‐Retzius cells (CRs), direct functional evidence is missing. As CRs powerfully excite GABAergic interneurons of the molecular layers, TRPV1 could play important roles in the regulation of layer‐specific processing. Here, we have taken advantage of calcium imaging with the genetically encoded indicator GCaMP6s and patch‐clamp techniques to study the responses of hippocampal CRs to the activation of TRPV1 by capsaicin, and have compared the effect of TRPV1 stimulation on synaptic transmission in layers innervated or non‐innervated by CRs. Capsaicin induced both calcium responses and membrane currents in ∼50% of the cell tested. Neither increases of intracellular calcium nor whole‐cell currents were observed in the presence of the TRPV1 antagonists capsazepine/Ruthenium Red or in slices prepared from TRPV1 knockout mice. We also report a powerful TRPV1‐dependent enhancement of spontaneous synaptic transmission onto interneurons with dendritic trees confined to the layers innervated by CRs. In conclusion, our work establishes that functional TRPV1 is expressed by a significant fraction of CRs and we propose that TRPV1 activity may regulate layer‐specific synaptic transmission in the hippocampus. Lastly, as CR density decreases during postnatal development, we also propose that functional TRPV1 receptors may be related to mechanisms involved in CR progressive reduction by calcium‐dependent toxicity/apoptosis.
Effects of elevated H+ and Pi on the contractile mechanics of skeletal muscle fibres from young and old men: implications for muscle fatigue in humans
Authors: Sundberg Christopher W. , Hunter Sandra K. , Trappe Scott W. , Smith Carolyn S. , Fitts Robert H.
Published: May 2018

Key points

The mechanisms responsible for the loss in muscle power and increased fatigability with ageing are unresolved.

We show that the contractile mechanics of fibres from the vastus lateralis of old men were well‐preserved compared to those of young men, but the selective loss of fast myosin heavy chain II muscle was strongly associated with age‐related decrements in whole‐muscle strength and power.

We reveal that the combination of acidosis (H+) and inorganic phosphate (Pi) is an important mediator of muscle fatigue in humans by inhibiting the low‐ to high‐force state of the cross‐bridge cycle and peak power, but the depressive effects of these ions on cross‐bridge function were similar in fibres from young and old men.

These findings suggest that the age‐related loss in muscle power is primarily determined by the atrophy of fast fibres, but the age‐related increased fatigability cannot be explained by an increased sensitivity of the cross‐bridge to H+ and Pi.

The present study aimed to identify the mechanisms responsible for the loss in muscle power and increased fatigability with ageing by integrating measures of whole‐muscle function with single fibre contractile mechanics. After adjusting for the 22% smaller muscle mass in old (73–89 years, n = 6) compared to young men (20–29 years, n = 6), isometric torque and power output of the knee extensors were, respectively, 38% and 53% lower with age. Fatigability was ∼2.7‐fold greater with age and strongly associated with reductions in the electrically‐evoked contractile properties. To test whether cross‐bridge mechanisms could explain age‐related decrements in knee extensor function, we exposed myofibres (n = 254) from the vastus lateralis to conditions mimicking quiescent muscle and fatiguing levels of acidosis (H+) (pH 6.2) and inorganic phosphate (Pi) (30 mm). The fatigue‐mimicking condition caused marked reductions in force, shortening velocity and power and inhibited the low‐ to high‐force state of the cross‐bridge cycle, confirming findings from non‐human studies that these ions act synergistically to impair cross‐bridge function. Other than severe age‐related atrophy of fast fibres (−55%), contractile function and the depressive effects of the fatigue‐mimicking condition did not differ in fibres from young and old men. The selective loss of fast myosin heavy chain II muscle was strongly associated with the age‐related decrease in isometric torque (r = 0.785) and power (r = 0.861). These data suggest that the age‐related loss in muscle strength and power are primarily determined by the atrophy of fast fibres, but the age‐related increased fatigability cannot be explained by an increased sensitivity of the cross‐bridge to H+ and Pi.
An investigation on the effect of humidity on the zero signal of a strain gauge measuring system
Authors: Khaled K. M. , Mahmoud G. M.
Published: May 2018

Humidity is one of the most important ambient factors influencing torque calibration readings. The present study addresses the effect of relative humidity on the readings of reference torque transduction and amplification devices. The results revealed a linear effect of increasing humidity on the readings of a DMP40 torque amplifier and a torque transducer at four different temperatures. Furthermore, humidity effects were smaller on the DMP40 amplifier than on the torque transducer across all four temperatures. The results also showed that the summed effects of humidity on amplifier and transducer calibration readings were larger when each device was operated under different humidity and temperature conditions (i.e. torque amplifier placed inside a controlled climate chamber and transducer outside, and vice-versa); as opposed to smaller summed effects, observed when both devices were operated under the same ambient conditions (i.e. both inside the chamber). Therefore, it is recommended to test the effect of humidity in setups where the two devices are under common humidity conditions. This is likely to lower the uncertainty parameter of obtained torque calibration readings and is a useful consideration for inter-laboratory comparisons and performance testing.
Spatial, Temporal, and Functional Assessment of LC3-Dependent Autophagy in Shigella flexneri Dissemination
Authors: Weddle Erin , Agaisse Hervé
Published: May 2018

Shigella flexneri
disseminates within the colonic mucosa by displaying actin-based motility in the cytosol of epithelial cells. Motile bacteria form membrane protrusions that project into adjacent cells and resolve into double-membrane vacuoles (DMVs) from which the bacteria escape, thereby achieving cell-to-cell spread.
The Human Papillomavirus E6 PDZ Binding Motif Links DNA Damage Response Signaling to E6 Inhibition of p53 Transcriptional Activity
Authors: Thatte Jayashree , Massimi Paola , Thomas Miranda , Boon Siaw Shi , Banks Lawrence
Published: May 2018

The cancer-causing HPV E6 oncoproteins all possess a PDZ binding motif at their extreme carboxy termini. Depending upon whether this motif is phosphorylated, E6 can recognize PDZ domain-containing proteins or members of the 14-3-3 family of proteins. We show here that DNA damage response pathways directly signal to the E6 PBM, resulting in Chk1- and Chk2-driven phosphorylation. This phosphorylation is particularly pronounced following treatment of cells with a variety of different chemotherapeutic drugs. A direct functional consequence of this signaling is to confer an enhanced ability upon E6 to inhibit p53 transcriptional activity in a proteasome-independent but phosphorylation-dependent manner. These results are the first example of DNA damage signaling pathways regulating PBM-PDZ interactions and provide the mechanistic link between E6 PBM function and perturbation of p53 activity.
Smc5/6 Antagonism by HBx Is an Evolutionarily Conserved Function of Hepatitis B Virus Infection in Mammals
Authors: Abdul Fabien , Filleton Fabien , Gerossier Laetitia , Paturel Alexia , Hall Janet , Strubin Michel , Etienne Lucie
Published: May 2018

Infection with hepatitis B virus (HBV) led to 887,000 human deaths in 2015. HBV has been coevolving with mammals for millions of years. Recently, the Smc5/6 complex, which has essential housekeeping functions, was identified as a restriction factor of human HBV antagonized by the regulatory HBx protein. Here we address whether the antiviral activity of Smc5/6 is an important evolutionarily conserved function. We found that all six subunits of Smc5/6 have been conserved in primates, with only Smc6 showing signatures of an “evolutionary arms race.” Using evolution-guided functional analyses that included infections of primary human hepatocytes, we demonstrated that HBx proteins from very divergent mammalian HBVs could all efficiently antagonize Smc5/6, independently of the host species and sites under positive selection. These findings show that Smc5/6 antiviral activity against HBV is an important function in mammals. They also raise the intriguing possibility that Smc5/6 may restrict other, yet-unidentified viruses.
Increased Usage of Antiseptics Is Associated with Reduced Susceptibility in Clinical Isolates of
Staphylococcus aureus
Authors: Hardy Katherine , Sunnucks Katie , Gil Hannah , Shabir Sahida , Trampari Eleftheria , Hawkey Peter , Webber Mark
Published: May 2018

Hospital-acquired infection is a major cause of morbidity and mortality, and regimes to prevent infection are crucial in infection control. These include the decolonization of vulnerable patients with methicillin-resistant
Staphylococcus aureus
(MRSA) carriage using antiseptics, including chlorhexidine and octenidine. Concern has been raised, however, regarding the possible development of biocide resistance. In this study, we assembled a panel of
S. aureus
isolates, including isolates collected before the development of chlorhexidine and octenidine and isolates, from a major hospital trust in the United Kingdom during a period when the decolonization regimes were altered. We observed significant increases in the MIC and minimum bactericidal concentration (MBC) of chlorhexidine in isolates from periods of high usage of chlorhexidine. Isolates with increased MICs and MBCs of octenidine rapidly emerged after octenidine was introduced in the trust. There was no apparent cross-resistance between the two biocidal agents. A combination of variable-number tandem repeat (VNTR) analysis, PCR for
qac
genes, and whole-genome sequencing was used to type isolates and examine possible mechanisms of resistance. There was no expansion of a single strain associated with decreased biocide tolerance, and biocide susceptibility did not correlate with carriage of
qac
efflux pump genes. Mutations within the NorA or NorB efflux pumps, previously associated with chlorhexidine export, were identified, however, suggesting that this may be an important mechanism of biocide tolerance. We present evidence that isolates are evolving in the face of biocide challenge in patients and that changes in decolonization regimes are reflected in changes in susceptibility of isolates.

IMPORTANCE
Infection in hospitals remains a major cause of death and disease. One way in which we combat this is by decolonizing at-risk patients from carriage of bacteria which can cause disease such as MRSA. This is done with antiseptics, including chlorhexidine and octenidine. There is concern, however, that bacteria may be able to become resistant to these antiseptics. In this study, we looked at isolates of MRSA and found that there was a correlation between the use of antiseptics and increased resistance in the isolates. We also suggest that the mechanism by which these more tolerant isolates may become resistant to antiseptics is that of changing a transport pump that exports these agents. This information suggests that we need to study the impact of antiseptics on clinically important bacteria more closely.
Heterotroph Interactions Alter
Prochlorococcus
Transcriptome Dynamics during Extended Periods of Darkness
Authors: Biller Steven J. , Coe Allison , Roggensack Sara E. , Chisholm Sallie W.
Published: May 2018

Prochlorococcus
is the most abundant photosynthetic organism on the planet. These cells play a central role in the physiology of surrounding heterotrophs by supplying them with fixed organic carbon. It is becoming increasingly clear, however, that interactions with heterotrophs can affect autotrophs as well. Here we show that such interactions have a marked impact on the response of
Prochlorococcus
to the stress of extended periods of darkness, as reflected in transcriptional dynamics. These data suggest that diel transcriptional rhythms within
Prochlorococcus
, which are generally considered to be strictly under the control of light quantity, quality, and timing, can also be influenced by biotic interactions. Together, these findings provide new insights into the importance of microbial interactions on
Prochlorococcus
physiology and reveal conditions where heterotroph-derived compounds may support autotrophs—contrary to the canonical autotroph-to-heterotroph trophic paradigm.
Environmental Sources of Bacteria Differentially Influence Host-Associated Microbial Dynamics
Authors: Cardona Cesar , Lax Simon , Larsen Peter , Stephens Brent , Hampton-Marcell Jarrad , Edwardson Christian F. , Henry Chris , Van Bonn Bill , Gilbert Jack A.
Published: May 2018

These results provide valuable insights into the ecological influence of exogenous microbial exposure, as well as laying the foundation for improving aquarium management practices. By comparing data for dolphins from aquaria that use natural versus artificial seawater, we demonstrate the potential influence of aquarium water disinfection procedures on dolphin microbial dynamics.
Lower gastrointestinal symptoms are associated with worse glycemic control and quality of life in type 1 diabetes mellitus
Authors: Leeds John S , Hadjivassiliou Marios , Tesfaye Solomon , Sanders David S
Published: May 2018

Objectives

Lower gastrointestinal symptoms are not well characterized in people with type 1 diabetes, and the effects on quality of life and glycemic control are unknown. This study aimed to determine the prevalence of lower gastrointestinal symptoms and the effects on glycemic control and quality of life, and to investigate for underlying causes.

Research design and methods

This is a prospective, cohort study in secondary care. Patients with type 1 diabetes completed a gastrointestinal symptom questionnaire and the Short Form 36 V.2 quality of life questionnaire and had their hemoglobin A1c measured. Patients with diarrhea were offered reassessment and investigation as per the national guidelines. Controls without diabetes were used to compare symptom prevalence and quality of life scores.

Results

706 with type 1 diabetes (mean age 41.9 years) and 604 controls (mean age 41.9 years) were enrolled. Gastrointestinal symptoms were significantly more frequent in type 1 diabetes compared with controls, in particular constipation (OR 2.4), diarrhea (OR 2.5), alternating bowel habit (OR 2.1), abdominal pain (OR 1.4), floating stools (OR 2.7), bloating (OR 1.4) and flatulence (OR 1.3) (all p<0.05). Previous pancreatitis was more frequent in type 1 diabetes (OR 4.6), but other gastrointestinal conditions were not. Gastrointestinal symptoms were associated with poorer glycemic control (p<0.01) and worse quality of life particularly in those with diarrhea. Investigation of those with diarrhea, including those with alternating bowel habit, (n=105), identified a cause in 72.3% with subsequent change in management.

Conclusions

Gastrointestinal symptoms are twice as common in type 1 diabetes and associated with poorer quality of life and glycemic control. Investigation of diarrhea in people with type 1 diabetes leads to a high yield of treatable conditions and a change in management in about three-quarters.
Understanding patient preference for physician attire: a cross-sectional observational study of 10 academic medical centres in the USA
Authors: Petrilli Christopher M , Saint Sanjay , Jennings Joseph J , Caruso Andrew , Kuhn Latoya , Snyder Ashley , Chopra Vineet
Published: May 2018

Objective

Several large studies have shown that improving the patient experience is associated with higher reported patient satisfaction, increased adherence to treatment and clinical outcomes. Whether physician attire can affect the patient experience—and how this influences satisfaction—is unknown. Therefore, we performed a national, cross-sectional study to examine patient perceptions, expectations and preferences regarding physicians dress.

Setting

10 academic hospitals in the USA.

Participants

Convenience sample of 4062 patients recruited from 1 June 2015 to 31 October 2016.

Primary and secondary outcomes measures

We conducted a questionnaire-based study of patients across 10 academic hospitals in the USA. The questionnaire included photographs of a male and female physician dressed in seven different forms of attire. Patients were asked to rate the provider pictured in various clinical settings. Preference for attire was calculated as the composite of responses across five domains (knowledgeable, trustworthy, caring, approachable and comfortable) via a standardised instrument. Secondary outcome measures included variation in preferences by respondent characteristics (eg, gender), context of care (eg, inpatient vs outpatient) and geographical region.

Results

Of 4062 patient responses, 53% indicated that physician attire was important to them during care. Over one-third agreed that it influenced their satisfaction with care. Compared with all other forms of attire, formal attire with a white coat was most highly rated (p=0.001 vs scrubs with white coat; p<0.001 all other comparisons). Important differences in preferences for attire by clinical context and respondent characteristics were noted. For example, respondents≥65 years preferred formal attire with white coats (p<0.001) while scrubs were most preferred for surgeons.

Conclusions

Patients have important expectations and perceptions for physician dress that vary by context and region. Nuanced policies addressing physician dress code to improve patient satisfaction appear important.
Fluid therapy in the emergency department: an expert practice review
Authors: Harris Tim , Coats Timothy J , Elwan Mohammed H
Published: May 2018

Intravenous fluid therapy is one of the most common therapeutic interventions performed in the ED and is a long-established treatment. The potential benefits of fluid therapy were initially described by Dr W B O’Shaughnessy in 1831 and first administered to an elderly woman with cholera by Dr Thomas Latta in 1832, with a marked initial clinical response. However, it was not until the end of the 19th century that medicine had gained understanding of infection risk that practice became safer and that the practice gained acceptance. The majority of fluid research has been performed on patients with critical illness, most commonly sepsis as this accounts for around two-thirds of shocked patients treated in the ED. However, there are few data to guide clinicians on fluid therapy choices in the non-critically unwell, by far our largest patient group. In this paper, we will discuss the best evidence and controversies for fluid therapy in medically ill patients.
Impact of flaxseed and soy nuts as dietary supplements on lipid profile, insulin sensitivity, and GLUT4 expression in ovariectomized rats
Authors: Dresseno Luciana P. , Lehnen Alexandre M. , Teló Gabriela , Silveira Ariel , Markoski Melissa M. , Machado Ubiratan F. , Schaan Beatriz D.
Published: May 2018

We assessed the effects of a diet with flaxseed or soy nuts versus estradiol on the lipid profile, insulin sensitivity, and glucose transporter type 4 (GLUT4) expression in ovariectomized female rats. Forty-four female Wistar rats (90 days old) underwent ovariectomy and were divided into 4 groups: C (standard diet), E (standard diet + subcutaneous 17β-estradiol pellets), L (standard diet + flaxseed + subcutaneous placebo pellets), and S (standard diet + soy nuts + subcutaneous placebo pellets). Customized diets and the insertion of pellets were started 21 days after ovariectomy and were continued for another 21 days. We measured body mass, insulin tolerance, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, and GLUT4 (in cardiac and adipose tissues). We found a lower body mass and a lower Lee index in group E and a trend toward improved insulin sensitivity in group S (p = 0.066). Groups L and S showed a better lipid profile when compared with group C. Microsomal GLUT4 increased in group L (in cardiac and adipose tissues), and plasma membrane GLUT4 increased in groups E, L, and S (in both tissues). We conclude that flaxseed and soy nuts as dietary supplements improve lipid profile and increase GLUT4 expression.
Transcriptional regulation of milk lipid synthesis by exogenous C16:0 and C18 fatty acids in bovine mammary epithelial cells
Authors: Dan Ni , Zhang Hang , Ao Changjin , Khas-Erdene
Published: May 2018

The objective of this study was to examine the effects of removing one fatty acid from a combination of long-chain fatty acids (LCFA) on milk lipogenesis in bovine mammary epithelial cells. The incubation concentration of LCFA was determined, and 100 μmol L−1 of C16:0, 5 μmol L−1 of C18:0, 100 μmol L−1 of cis-9 C18:1, 25 μmol L−1 of n-6 C18:2, and 1.2 μmol L−1 of n-3 C18:3 were used in the study. Treatments were C16:0, C18:0, C18:1, C18:2, and C18:3 combinations as control; control absent of C16:0 as A-C16:0; control absent of C18:0 as A-C18:0; control absent of C18:1 as A-C18:1; control absent of C18:2 as A-C18:2; control absent of C18:3 as A-C18:3. Results showed that compared with control, fatty acid synthetase expression was reduced by A-C18:0 and A-C18:1. Palmitic acid decreased expression of lipoprotein lipase. Compared with control, the expression of stearoyl-coenzyme A desaturase-1 and cluster of differentiation 36 was reduced by all treatments. Peroxisome proliferator-activated receptor-α expression was down-regulated by A-C16:0, A-C18:0, A-C18:1, and A-C18:2. Sterol regulatory element binding factor-1 was decreased when treated with A-C18:0, A-C18:1, and A-C18:2. Cells lack of 18-carbon fatty acid synthesized lower amount of intracellular triglyceride compared with control.
Experimental and numerical study of reinforced concrete interior wide beam-column joints subjected to lateral load
Authors: Mirzabagheri Sara , Tasnimi Abbas Ali , Issa Fadwa
Published: May 2018

Past researches showed that the energy dissipation capacity of the wide beam-column joints was not sufficient. So, two full-scale reinforced concrete interior wide beam-column joints were tested under quasi-static cyclic loads and the performance of the specimens was studied experimentally and numerically. Effect of using wide beams in two directions was investigated and it became clear that the longitudinal reinforcement of transverse wide beam had significant effect on the seismic behavior of the joints. Flexural hinging mechanism in the wide beams occurred instead of torsion brittle mode of failure. Effect of eccentric beams on joints is one of the areas needing research in ACI 352R-02. In the numerical study, it was seen that damage of the joints was concentrated to one side of the joints that the beams shifted to. Besides, concrete grade did not have much effect on behavior of the joint.
Observed nonlinearities in a DC semiconductor-gas discharge system
Authors: Cayli Y.K. , Mansuroglu D. , Uzun-Kaymak I.U.
Published: May 2018

Nonlinear behaviour of a direct current (DC) driven semiconductor-gas discharge plasma is investigated experimentally. The setup consists of two planar electrodes separated by a gap of 1 mm. Plasma glow is generated between a semiconductor cathode and a transparent anode using nitrogen gas at partial atmospheric pressure. Nonlinear behavior of the discharge is investigated by varying the applied DC voltage while monitoring the plasma current (I), voltage (V), and the optical emission, (i.e., amplified voltage measurements obtained using a photodiode and an amplifier). The discharge behaves oscillatory in time. By increasing the applied voltage, the system evolves into higher frequency oscillations with sub-harmonics. In fact, period doublings are observed in these systems, as shown in earlier publications by our research group. In this study, we investigate the mode coupling nature of these oscillations using a Fourier transform based spectral analysis.
Shell model description of the 0+ and 0− excited states in sd shell nuclei
Authors: Bouhelal M. , Saidane N. , Belaid S. , Haas F.
Published: May 2018

The purpose of this work is to describe, in light of shell model calculations using the PSDPF interaction, the particular states with J = 0 in sd shell nuclei. These states are difficult to observe. It is well known that the ground state in even–even nuclei has Jπ = 0+ and therefore we are interested in describing their first excited [Formula: see text] states. We have also studied the first and second excited 0− states in all sd nuclei. The experimental and theoretical excitation energies of these states were confronted. This study allowed us to make predictions of the existence of [Formula: see text] and (or) [Formula: see text] states in nuclei, which do not possess these states, or to have an idea of their excitation energies for possible experiments in the future.
Is dark matter and black hole cosmology an effect of Born’s reciprocal relativity theory?
Authors: Perelman Carlos Castro
Published: May 2018

Born’s reciprocal relativity theory (BRRT), based on a maximal proper-force, maximal speed of light, and inertial and non-inertial observers, is re-examined in full detail. Relativity of locality and chronology are natural consequences of this theory, even in flat phase space. The advantage of BRRT is that Lorentz invariance is preserved and there is no need to introduce Hopf algebraic deformations of the Poincaré algebra, de Sitter algebra, nor non-commutative space–times. After a detailed study of the notion of generalized force, momentum, and mass in phase space, we explain that what one may interpret as “dark matter” in galaxies, for example, is just an effect of observing ordinary galactic matter in different accelerating frames of reference than ours. Explicit calculations are provided that explain these novel relativistic effects due to the accelerated expansion of the Universe, and which may generate the present-day density parameter value ΩDM ∼ 0.25 of dark matter. The physical origins behind the numerical coincidences in black hole cosmology are also explored. We finalize with a rigorous study of the curved geometry of (co)tangent bundles (phase space) within the formalism of Finsler geometry, and provide a short discussion on Hamilton spaces.
The functional states of angular quantum numbers and Ne + H2+ (ν = 0, j = 2) → NeH+ + H reaction mechanism
Authors: Tanış Emine , Yılmaz Engin , Karabulut Ezman
Published: May 2018

The behaviors of Legendre polynomials representing angular movements are independent of the type of reaction and can be studied in detail paying attention to the changes on effective and centrifugal potentials. For the title reaction, dynamic calculations taking into account the effects of potential energy surfaces have been investigated using the real wave packet method on the most realistic potential energy surface (LZHH) recently obtained. The total electrical dipoles and energies were also calculated in the corresponding quantum states of the molecular system.
Combined effects of oblateness and photogravitational perturbations on the stability of the equilibrium points in the relativistic RTBP
Authors: Abd El-Bar S.E. , Abd El-Salam F.A.
Published: May 2018

In this work the stability of all equilibrium points in the photogravitational relativistic restricted three-body problem (RTBP) with oblate primaries is investigated for arbitrary RTBP systems. The four roots of the RTBP systems constituted from the Sun–planet of the solar system are computed as a computational example. The computation emphasizes the instability of all collinear points in the whole range of mass ratio. In the case of triangular points, the stability regions are affected differently according to the kind of perturbations. The different cases are plotted as well as analyzed.
A high omega-3 fatty acid diet rapidly changes the lipid composition of cardiac tissue and results in cardioprotection
Authors: Desnoyers Mélissa , Gilbert Kim , Madingou Ness , Gagné Marc-André , Daneault Caroline , Des Rosiers Christine , Rousseau Guy
Published: May 2018

The present study was designed to ascertain the effects of 3 diets with different omega-3/6 fatty acid ratios on infarct size and the modifications that these diets induce in the lipid composition of cardiac tissue. Sprague-Dawley rats were fed omega-3/6 fatty acid diets with 1:1, 1:5, or 1:20 ratios for at least 10 days, followed by occlusion of the left anterior descending artery for 40 min and 24 h of reperfusion. Infarct size was significantly smaller in the 1:1 group than in the other groups. Significantly higher concentrations of the omega-3 fatty acids eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid were found in the 1:1 group than in the other groups. Omega-6 polyunsaturated fatty acid levels were similar between groups, although they were higher in the 1:5 and 1:20 groups than in the 1:1 group. Margaric acid concentrations were higher in the 1:1 group than in the other groups. Docosahexaenoic acid levels in cardiac tissue and infarct size were significantly correlated with no other significant links being apparent. The present study indicated that a 1:1 omega-3/6 fatty acid ratio protected against ischemia and was associated with increased omega-3 fatty acid composition of cardiac tissue.
Thermodynamics and glassy phase transition of regular black holes
Authors: Javed Wajiha , Yousaf Z. , Akhtar Zunaira
Published: May 2018

This paper is aimed to study thermodynamical properties of phase transition for regular charged black holes (BHs). In this context, we have considered two different forms of BH metrics supplemented with exponential and logistic distribution functions and investigated the recent expansion of phase transition through grand canonical ensemble. After exploring the corresponding Ehrenfest’s equation, we found the second-order background of phase transition at critical points. In order to check the critical behavior of regular BHs, we have evaluated some corresponding explicit relations for the critical temperature, pressure and volume and draw certain graphs with constant values of Smarr’s mass. We found that for the BH metric with exponential configuration function, the phase transition curves are divergent near the critical points, while glassy phase transition has been observed for the Ayón–Beato-García–Bronnikov (ABGB) BH in n = 5 dimensions.
Effect of noncommutativity on the spectrum of free particle and harmonic oscillator in rotationally invariant noncommutative phase space
Authors: Gnatenko Kh. P. , Shyiko O. V.
Published: May 2018

We consider rotationally invariant noncommutative algebra with tensors of noncommutativity constructed with the help of additional coordinates and momenta. The algebra is equivalent to the well-known noncommutative algebra of canonical type. In the noncommutative phase space, rotational symmetry influence of noncommutativity on the spectrum of free particle and the spectrum of harmonic oscillator is studied up to the second-order in the parameters of noncommutativity. We find that because of momentum noncommutativity, the spectrum of free particle is discrete and corresponds to the spectrum of harmonic oscillator in the ordinary space (space with commutative coordinates and commutative momenta). We obtain the spectrum of the harmonic oscillator in the rotationally invariant noncommutative phase space and conclude that noncommutativity of coordinates affects its mass. The frequency of the oscillator is affected by the coordinate noncommutativity and the momentum noncommutativity. On the basis of the results, the eigenvalues of squared length operator are found and restrictions on the value of length in noncommutative phase space with rotational symmetry are analyzed.
Tunable magnetic properties of the nanoporous hybrid multilayer arrays
Authors: Tian Qingkun , Zhang Weiwei , Belotelov Vladimir , Song Yujun
Published: May 2018

Hybrid multilayer films system permits a lot of realization methods of tailoring of the magnetic properties. In this work, nanoporous hybrid multilayer system Ag was fabricated from anodic aluminum oxide (AAO) by a magnetron sputtering methods of room temperature. It is demonstrated that the magnetic properties can be flexibly manipulated by the substrate, noble metal (i.e. silver), the thickness of the ferromagnetic magnetic material (CoFeB) and the indium tin oxide (ITO).
Semi-Dirac point and its transport properties in two-dimensional deformed hexagonal lattice
Authors: Ye Pei-Pei , Xu Lei , Zhang Jun
Published: May 2018

We investigate the effect of uniaxial tensile stress on the electronic structure and transport properties of hexagonal lattice via a tight-binding approach. We find two Dirac points merging into a single point to generate a semi-Dirac cone as the tensile stress increases. The semi-Dirac cone is anisotropic with linear and parabolic dispersions at distinct directions. For a larger tensile stress, a band gap can be opened which indicates a phase transition from metallic phase to insulator phase. In the presence of magnetic field, the degeneracies of all Landau levels are lifted only partially yielding an unconventional Hall conductance with a step size of [Formula: see text] at each non-equidistant Landau level.
Unrelated BCS-like pairing pseudogap and critical superconducting transition temperature in various cuprate compounds
Authors: Dzhumanov S. , Karimboev E. X. , Djumanov Sh. S.
Published: May 2018

The smooth evolution of the energy gap observed in the tunneling and angle-resolved photoemission spectra (ARPES) of high-[Formula: see text] cuprates with lowering the temperature from a pseudogap state above the critical temperature [Formula: see text] to a superconducting state below [Formula: see text], has been poorly interpreted as the evidence that the pseudogap must have the same origin as the superconducting order parameter, and therefore, must be related to [Formula: see text]. We argue that such an explanation of the tunneling gap and ARPES data is misleading. We show that the BCS-like energy gap (or pseudogap) opening in the electronic excitation spectrum of underdoped-to-overdoped cuprates at a characteristic temperature [Formula: see text] and the true superconducting order parameter appearing only at [Formula: see text] are unrelated. The superconducting phenomenon in unconventional cuprate superconductors is fundamentally different from the BCS-like pairing of fermionic quasiparticles, and the superconducting transition temperature [Formula: see text] is not determined by the BCS-like gap formation. The unusual superconducting order parameter in these high-[Formula: see text] materials appears at [Formula: see text] and coexists with the BCS-like gap (or pseudogap) below [Formula: see text].
Post-Lie algebra structures for nilpotent Lie algebras
Authors: Burde Dietrich , Ender Christof , Moens Wolfgang Alexander
Published: May 2018

We study post-Lie algebra structures on [Formula: see text] for nilpotent Lie algebras. First, we show that if [Formula: see text] is nilpotent such that [Formula: see text], then also [Formula: see text] must be nilpotent, of bounded class. For post-Lie algebra structures [Formula: see text] on pairs of [Formula: see text]-step nilpotent Lie algebras [Formula: see text] we give necessary and sufficient conditions such that [Formula: see text] defines a CPA-structure on [Formula: see text], or on [Formula: see text]. As a corollary, we obtain that every LR-structure on a Heisenberg Lie algebra of dimension [Formula: see text] is complete. Finally, we classify all post-Lie algebra structures on [Formula: see text] for [Formula: see text], where [Formula: see text] is the three-dimensional Heisenberg Lie algebra.
An age-structured continuum model for myxobacteria
Authors: Degond Pierre , Manhart Angelika , Yu Hui
Published: May 2018

Myxobacteria are social bacteria, that can glide in two dimensions and form counter-propagating, interacting waves. Here, we present a novel age-structured, continuous macroscopic model for the movement of myxobacteria. The derivation is based on microscopic interaction rules that can be formulated as a particle-based model and set within the Self-Organized Hydrodynamics (SOH) framework. The strength of this combined approach is that microscopic knowledge or data can be incorporated easily into the particle model, whilst the continuous model allows for easy numerical analysis of the different effects. However, we found that the derived macroscopic model lacks a diffusion term in the density equations, which is necessary to control the number of waves, indicating that a higher order approximation during the derivation is crucial. Upon ad hoc addition of the diffusion term, we found very good agreement between the age-structured model and the biology. In particular, we analyzed the influence of a refractory (insensitivity) period following a reversal of movement. Our analysis reveals that the refractory period is not necessary for wave formation, but essential to wave synchronization, indicating separate molecular mechanisms.
Free to move or trapped in your group: Mathematical modeling of information overload and coordination in crowded populations
Authors: Ciallella Alessandro , Cirillo Emilio N. M. , Curşeu Petru L. , Muntean Adrian
Published: May 2018

We present modeling strategies that describe the motion and interaction of groups of pedestrians in obscured spaces. We start off with an approach based on balance equations in terms of measures and then we exploit the descriptive power of a probabilistic cellular automaton model.

Based on a variation of the simple symmetric random walk on the square lattice, we test the interplay between population size and an interpersonal attraction parameter for the evacuation of confined and darkened spaces. We argue that information overload and coordination costs associated with information processing in small groups are two key processes that influence the evacuation rate. Our results show that substantial computational resources are necessary to compensate for incomplete information — the more individuals in (information processing) groups the higher the exit rate for low population size. For simple social systems, it is likely that the individual representations are not redundant and large group sizes ensure that this non-redundant information is actually available to a substantial number of individuals. For complex social systems, information redundancy makes information evaluation and transfer inefficient and, as such, group size becomes a drawback rather than a benefit. The effect of group sizes on outgoing fluxes, evacuation times and wall effects is carefully studied with a Monte Carlo framework accounting also for the presence of an internal obstacle.
The propagation phenomenon of solutions of a parabolic problem on the sphere
Authors: Kazmierczak Bogdan , Tsai Je-Chiang , Bialecki Slawomir
Published: May 2018

In this paper, we study propagation phenomena on the sphere using the bistable reaction–diffusion formulation. This study is motivated by the propagation of waves of calcium concentrations observed on the surface of oocytes, and the propagation of waves of kinase concentrations on the B-cell membrane in the immune system. To this end, we first study the existence and uniqueness of mild solutions for a parabolic initial-boundary value problem on the sphere with discontinuous bistable nonlinearities. Due to the discontinuous nature of reaction kinetics, the standard theories cannot be applied to the underlying equation to obtain the existence of solutions. To overcome this difficulty, we give uniform estimates on the Legendre coefficients of the composition function of the reaction kinetics function and the solution, and a priori estimates on the solution, and then, through the iteration scheme, we can deduce the existence and related properties of solutions. In particular, we prove that the constructed solutions are of [Formula: see text] class everywhere away from the discontinuity point of the reaction term. Next, we apply this existence result to study the propagation phenomenon on the sphere. Specifically, we use stationary solutions and their variants to construct a pair of time-dependent super/sub-solutions with different moving speeds. When applied to the case of sufficiently small diffusivity, this allows us to infer that if the initial concentration of the species is above the inhomogeneous steady state, then the species will exhibit the propagating behavior.
XVA PRINCIPLES, NESTED MONTE CARLO STRATEGIES, AND GPU OPTIMIZATIONS
Authors: ABBAS-TURKI LOKMAN A. , CRÉPEY STÉPHANE , DIALLO BABACAR
Published: May 2018

We present a nested Monte Carlo (NMC) approach implemented on graphics processing units (GPUs) to X-valuation adjustments (XVAs), where X ranges over C for credit, F for funding, M for margin, and K for capital. The overall XVA suite involves five compound layers of dependence. Higher layers are launched first, and trigger nested simulations on-the-fly whenever required in order to compute an item from a lower layer. If the user is only interested in some of the XVA components, then only the sub-tree corresponding to the most outer XVA needs be processed computationally. Inner layers only need a square root number of simulation with respect to the most outer layer. Some of the layers exhibit a smaller variance. As a result, with GPUs at least, error-controlled NMC XVA computations are doable. But, although NMC is naively suited to parallelization, a GPU implementation of NMC XVA computations requires various optimizations. This is illustrated on XVA computations involving equities, interest rate, and credit derivatives, for both bilateral and central clearing XVA metrics.
Theoretical investigation of (tetrazine-3,6diyl) dihydrazinecarboxamide-based high-nitrogen-containing energetic macromolecules
Authors: Devi Alka , Ghule Vikas D.
Published: May 2018

Density-function-theory calculations were performed to find the performance of a series of 2,2’-(1,2,4,5-tetrazine-3,6diyl) dihydrazinecarboxamide-based nitrogen-rich macrocyclic compounds as an energetic plasticizer. Reliable methods have been used to predict energetic properties such as gas-phase and solid-phase heat of formation (HOF), density, detonation velocity, detonation pressure, explosive power, heat of combustion, heat of detonation, specific impulse, flame temperature, brisance, and sensitivity. All the designed macrocycles possess a nitrogen content of over 48%. The designed compounds show positive HOFs and high predicted densities ranging from 1.81[Formula: see text]g/cm3to 1.86[Formula: see text]g/cm3. The predicted properties were compared with GAP, polyGLYN and their monomers which establish the designed macrocycles of interest for further investigations concerning their suitability as plasticizers in energetic formulations.