bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical simulation and research on improving aerodynamic performance of vertical axis wind turbine by co-flow jet
Authors: Sun Xiaojing , Xu Yingqiao , Huang Diangui
Published: January 2019

The co-flow jet (CFJ) based active flow control method is a new approach for suppressing the flow separation on the blade, delaying the stall, and enhancing the lift. In this study, a detailed numerical analysis of the flow field developing around a Darrieus wind rotor equipped with CFJ is presented in order to explore the effectiveness of CFJ in the efficiency improvement of vertical axis wind turbines (VAWTs). Unsteady Computational Fluid Dynamics simulations of the straight one-bladed and three-bladed rotors with the NACA0015 profile, using the shear stress transport (SST) k-ω turbulence model, were conducted. As a result, the effects of jet operational parameters such as the injection site and the momentum coefficient on the aerodynamic performance of the straight-bladed Darrieus vertical axis wind turbine (VAWT) have been comprehensively studied. The numerical results suggest that CFJ would be capable of recovering some of the power loss due to blade stall and its control effectiveness is more pronounced with the increase in the jet momentum coefficient. In addition, a power saving method for intermittent injection of a CFJ in accordance with the cyclic variation of the angle of attack is proposed and our results show that the stalling characteristics around a VAWT blade especially at low tip speed ratios can be considerably improved using intermittent CFJ which requires much less additional energy input.
Numerical simulation of the penetration of granite at wide-range velocities with a new SPH method
Authors: Zhang Guo-xing , Qiang Hong-fu , Wang Guang , Huang Quan-zhang , Yang Yuan-qing
Published: January 2019

A new Smoothed Particle Hydrodynamics (SPH) method is used to simulate the deformation of granite at large strain and high strain rates during penetration in the study. In order to describe the nonlinear deformation and failure characteristics of rock and metallic materials, Holmquist-Johnson-Cook (HJC) constitutive and damage models were applied to granite plates. In addition, Johnson-Cook (J-C) constitutive model and Gruneisen equation of state were applied to the projectile body, respectively. The projectile body and granite plates were discretized into Lagrangian particles during simulation. Through the simulation of three-dimensional penetration process of granite plates by self-made program at the initial penetration velocity of 0∼4000m/s, this article compares and analyzes the penetration results of different projectile bodies, fitting the curve of the penetration depth versus the initial penetration velocity in solid, semi-fluid and fluid penetration fields. The numerical results show the relationship between the penetration depth and the initial penetration velocity in the range of 0∼4000m/s. As the initial penetration velocity increases, the penetration depth shows an increasing trend in the solid penetration area (V0 < 1421m/s), and a decreasing trend in the semi-fluid penetration area (1421m/s < V0 < 1700m/s). When the initial velocity comes to the range of V0 > 1700m/s, the penetration is in a complete fluid penetrating state, and the penetration depth increases nonlinearly with the initial penetration velocity. The increasing curve gradually flattens out if V0 > 3000m/s, and reaches the peak value.
Dynamic control strategy for the participation of variable speed wind turbine generators in primary frequency regulation
Authors: Abouzeid Said I. , Guo Yufeng , Zhang Hao-Chun
Published: January 2019

This paper introduces a novel strategy for the participation of variable speed wind turbine generators in primary frequency regulation. The proposed strategy is based on modifying the droop and inertia emulation control loops in such a way to help the wind turbine provide a secure frequency response throughout the dynamic control of the turbine tip-speed ratio and de-loading percentage. The proposed control does not directly act on the active power reference such as classical droop and inertia controls but on adjusting the rotor speed set-point and the pitch angle directly in response to the frequency deviation. The wind turbine is assumed to operate at 10% de-loading percentage under normal conditions. The over-speed, pitch control, and de-rated control are combined together to provide a power reserve. The control strategy is valid for all the wind speed ranges and does not require any direct wind measurements as a control input. The simulation results confirm that the proposed frequency response strategy improves effectively the frequency stabilization of the power system and has the ability to provide transient and steady-state power-sharing within the stable and secure limits.
On the structure, synthesis, and characterization of ultrafast blue-emitting CsPbBr3 nanoplatelets
Authors: Tomanová Kateřina , Čuba Václav , Brik Mikhail G. , Mihóková Eva , Martinez Turtos Rosana , Lecoq Paul , Auffray Etiennette , Nikl Martin
Published: January 2019

Recent developments in medical imaging techniques, in particular, those in time-of-flight positron emission tomography put new challenges on scintillating material performance that cannot be fulfilled by conventional scintillators. Bright and ultrafast nanoparticles represent promising candidates to build up an advanced detection system needed. We synthesize colloidal CsPbBr3 nanoplatelets emitting blue light with fast sub-nanosecond decay. We also prepare a nanocomposite material by embedding the nanoplatelets in the polystyrene matrix. We show that blue emission is preserved provided the composite is not exposed to UV/vis light and/or elevated temperatures. Motivated by conflicting information from the literature about the room temperature structure of colloidal CsPbX3 (X = Cl, Br, I) particles, that results being orthorhombic, rather than cubic, we perform ab initio electronic structure calculations of bulk crystals with an orthorhombic structure. We calculate optical properties, as well as exciton diameters and binding energies and compare them to those previously obtained for cubic CsPbX3 crystals.
Multifrequency seashell antenna based on resonant cold-electron bolometers with kinetic Inductance Nanofilters for CMB measurements
Authors: Mukhin A. S. , Kuzmin L. S. , Chiginev A. V. , Blagodatkin A. V. , Zbrozhek V. O. , Gordeeva A. V. , Pankratov A. L.
Published: January 2019

A novel type of the seashell slot antenna with internal filters by the capacitance of resonant cold-electron bolometers (RCEB) and kinetic inductance of the NbN superconducting nanostrip has been realized for multifrequency pixels. Seashell antenna gives the opportunity to connect opposite slots by coplanar waveguides (CPW) instead of microstrip lines (MSL). A conventional multifrequency pixel combines a wideband antenna and narrowband filters with long microstrip lines with unavoidable losses and overlaps. Another problem is the frequency dependent beam width due to a fixed pixel diameter for multiple frequencies. The main advantage of the seashell antenna with nano-filters is independent tuning of the separate pairs of slots for each frequency avoiding frequency dependence of the beam width. We used λ/2 slots for 75 and 105 GHz, feeding by CPW near the end of slots for RF matching. Each RCEB includes two SIN (Superconductor-Insulator-Normal) tunnel junctions with a nano-absorber and NbN kinetic inductance of 450 or 310 pH. SIN junctions had capacitances of 9.3 and 7.2 fF and absorber matched to a wave impedance of the antenna near 50 Ohm. Kinetic inductance value was estimated at the level of 35 pH/sq. RF testing was done at 300 mK irradiating this chip by sweep generator from 60 to 120 GHz. The response curves showed clear resonances at 75 and 105 GHz with a quality factor of 10 and 7. These experiments confirm that the seashell antenna with the internal RCEB filters can be used for frequency selection in compact multiband pixels.
Microwave-excited hybrid thermoacoustic and ultrasound imaging with microwave pulse-width modulation
Authors: Zhao Yuan , Chi Zihui , Ge Shaoli , Zhao Rui , Mbolle Augustine Meombe , Jiang Huabei
Published: January 2019

We present a method that allows for hybrid microwave-excited thermoacoustic and ultrasound (HMTAU) imaging without an additional ultrasound transmitting circuitry. The same microwave pulse is used to simultaneously generate thermoacoustic (TA) signals from the sample by the thermoacoustic effect, and ultrasound (US) signals from the piezoelectric transducer by the inverse piezoelectric effect. The same transducer collects the US signals reflected from the sample as a result of the US pulse (pulse-echo) and the TA signals as a result of the sample absorbing microwaves. Experiments are conducted to show how the microwave pulse-width significantly impacts the excitation efficiency of ultrasonic waves, which can reduce the requirement for microwave power. We found that the mechanical response of the US transducer to this transient expansion shows a maximum if the pulse-width of the microwave is close to half of the center period of the US transducer. We also use phantom experiments to demonstrate the complementary contrast mechanisms of the two modalities. The results obtained indicate that our method offers the potential of a low-cost dual-modality technique for noninvasive biomedical imaging.
Effect of high power microwave injection on ozone balance
Authors: Hu Yaogai , Zhu Xiaoli , Chen Lina , Zhao Zhengyu
Published: January 2019

High power microwave (HPM) injection into the troposphere to block the chain of chlorofluorocarbons (CFCs) or injection into the stratosphere to promote ozone generation are two feasible methods to artificially affect the ozone number concentration. Based on Maxwell’s equations and current density control equations, this study adopts the finite difference time domain (FDTD) method to quantitatively analyze the process of HPM injection into different heights of atmosphere. By taking consideration of the main atmospheric components and the major chemical reactions in the atmospheric, the decomposition of CFCs and the change of the ozone number density is also quantitatively simulated in response to the injection of single pulse microwaves. The numerical simulation results show that under the injection of high power microwaves, the number density of electrons increased exponentially with time, reaching a maximum value of 1017cm-3, and it increased considerably with the pulse time of injected high power microwaves and finally saturates when the state of atmospheric breakdown occurs. The decomposition of CFCs mainly occurs in the electron relaxation process, and the decomposition rate can reach 6% according to the simulation result. Before the atmosphere breaks down occurs, increase of microwave intensity or pulse width facilitates the production of more free electrons, which can consequently lead to a considerable increase in the ozone number density in ozone layer for a prolonged period.
Coupled continuum-discrete modeling of rammed floating stone column installation
Authors: Wang Jian , Li Qimin
Published: January 2019

To analyze the influence of stone column installation on the enhancement of soft ground and to reveal the physical aspects of the soil-pile interaction (SPI) mechanism, the stone column installation process is fully simulated by the three-dimensional continuous-discrete coupling (CDC) method for the first time. The stone column is simulated by particles in a discrete domain, the soft foundation and hammer are simulated by solid elements in a continuum domain, and the soil-pile interface and soil-hammer interface are simulated by coupling faces. Four installation effects, including the bottom enlargement effect, the branch effect, the heave effect and the penetration effect, are found during the installation process through the analysis of the displacement and stress field of the soft soil around the stone column. The bottom enlargement effect and the branch effect help improve the bearing capacity of the soft foundation, the heave effect helps to offset the ground subsidence, and the penetration effect reflects the penetration of the particles into the soft soil as they are punched by the hammer. Parametric studies of the stone backfill show that the average particle size, the friction coefficient and the bond strength ratio are linearly positively correlated with the displacement of the soil around the stone column, but the displacement of the soil decreases with a negative power law as the particle stiffness ratio increases. These research results are helpful for evaluating the influence of the stone backfill and the installation process on the reinforcement effect of the soft ground and for improving the accurate design and control level of soft ground strengthened by stone columns.
Synthetic Studies on the Marine-Derived Sesquiterpene (+)-Viridianol: Divergent Behaviour of Two Structurally Related, Ring-Fused Cyclopropanes Under the Same Hydrogenolytic Conditions
Authors: Bolte Benoit , Tang Fei , Lan Ping , Willis Anthony C. , Banwell Martin G.
Published: January 2019

Hydrogenolytic cleavage of the ring-fused cyclopropane 11 using hydrogen in the presence of platinum oxide afforded the gem-dimethylated cyclohexane 12 in 99% yield. In contrast, analogous treatment of congener 13 afforded only trace amounts of the targeted and gem-dimethylated sesquiterpene (+)-viridianol (1), the major products of reaction now being the vic-dimethylated compound 14 and the 2-fold ring-cleavage product 15.
Analysis of forest fire fatalities in Southern Europe: Spain, Portugal, Greece and Sardinia (Italy)
Authors: Molina-Terrén Domingo M. , Xanthopoulos Gavriil , Diakakis Michalis , Ribeiro Luis , Caballero David , Delogu Giuseppe M. , Viegas Domingos X. , Silva Carlos A. , Cardil Adrián
Published: January 2019

Wildfire fatalities remain a significant problem in Mediterranean Europe. Although there is a strong inter-annual variability with regard to their number, repeated tragic accidents remind us of this grim occurrence, despite the increasing firefighting capacity aimed to improve human safety. In this paper, we present an analysis of the 865 fatalities caused by wildfires in the 1945–2016 period. Data originating from national databases were merged, contextual and weather factors related to the accidents that caused these deaths were documented and analysed to explore probable relationships with the number and type of fatalities. Results show a major rise of fatalities in late 1970s in the four regions of Greece, Sardinia (Italy), Spain and Portugal. Fatalities present a strong seasonality in summer months, as expected. Overall, Spain has the highest absolute numbers of fatalities; however, normalisations by population, and burned and forest area show that annual number of fatalities is comparatively smaller. Certain other factors showed correlation with mortality. Civilians were the most affected group in Greece (65%) and Sardinia (58%), but not in Spain and Portugal. Findings indicate that an in-depth revision of fire-management policies and practices is required, with emphasis on prevention planning in urban areas, and better training of the firefighting resources.
Effect of age and hearing loss on sentence perception in noise using temporal envelope and temporal fine structure cues
Authors: Jain Saransh , Nataraja Nuggehalli Puttareviyah
Published: January 2019

Purpose:

The perception of speech is affected by many physical, physiological and pathological factors related to the stimuli and the listener. Researchers have addressed the effect of each of these factors independently on the perception of speech. In everyday situations, these factors do not occur in isolation but they may occur simultaneously and affect the overall perception of speech. The information on the extent to which each of these factors affect the speech perception is seldom being investigated.

Methods:

The present study explored the role of temporal envelope and temporal fine structures in the perception of sentences in noise by normal hearing young & older adults; and young & older adults with hearing loss. The envelope and fine structures of the sentences were extracted based on Hilbert transformation using Matlab software. The effect of noise was estimated by processing the sentences in quiet and at 0 dB and -5 dB SNR. The sentences were also filtered using 4, 8, 16 and 32 frequency channels to assess the role of frequency filtering on speech perception.

Results:

The envelope was more important for speech perception in both quiet and noise. The perception of speech was inversely proportional to age, hearing loss and noise levels, whereas it was directly proportional to the number of frequency channels.

Conclusion:

These findings indicate that the temporal envelope is important for speech perception in noise. The research findings may help in designing new signal processing strategies for hearing aids and cochlear implants based on the envelope cues.
Acoustic energy harvesting with irradiated cross-linked polypropylene piezoelectret films
Authors: Xue Yuan , Zhao Jinfeng , Zhang Xiaoqing , Sessler Gerhard M , Kupnik Mario
Published: January 2019

Piezoelectret films prepared by irradiated cross-linked polypropylene (IXPP) not only feature a large figure of merit (d
33 · g
33, FoM) and a nearly flat response of the sensitivity as a microphone (4 mV Pa−1) in the audio range, but also exhibit a good impedance match to air. Therefore, this material is appropriate for air-coupled sonic and ultrasonic applications. In this work, we report acoustic energy harvesting using IXPP piezoelectret films without mass loading both in ultrasonic and low-frequency ranges. Under an input sound pressure level (SPL) of 100 dB (or 2 Pa) and a resonance frequency of 53 kHz, a maximum output power of 7.2 nW is obtained for an IXPP film harvester. Despite its high resonance frequency, the large FoM of IXPP piezoelectret films suggests itself to be a promising candidate also for low-frequency acoustic energy harvesting with the help of Helmholtz resonators. An output power of 10.3 nW is achieved for a harvester with a 16 cm2 large IXPP film within a Helmholtz resonator, which features a resonance frequency of 900 Hz, with an optimized load resistance of 962 kΩ under an input SPL of 100 dB. In comparison to acoustic energy harvesters based on ferroelectric polymer polyvinylidene fluoride cantilever beams, our devices have much higher output power density under the same conditions and much broader bandwidth. Theoretical analysis and numerical simulations are performed to confirm the experimental results. Moreover, the output power of the IXPP acoustic energy harvesters can be further improved by increasing the active area of the piezoelectret films.
A topological classification of locally constant potentials via zero-temperature measures
Authors: Wolf Christian , Yang Yun
Published: January 2019

We provide a topological classification of locally constant functions over subshifts of finite type via their zero-temperature measures. Our approach is to analyze the relationship between the distribution of the zero-temperature measures and the boundary of higher dimensional generalized rotation sets. We also discuss the regularity of the localized entropy function on the boundary of the generalized rotation sets.
Combinatorial characterization of the weight monoids of smooth affine spherical varieties
Authors: Pezzini Guido , Van Steirteghem Bart
Published: January 2019

Let

G
G

be a connected reductive group, and let

X
X

be a smooth affine spherical

G
G

-variety, both defined over the complex numbers. A well-known theorem of I. Losev’s says that

X
X

is uniquely determined by its weight monoid, which is the set of irreducible representations of

G
G

that occur in the coordinate ring of

X
X

. In this paper, we use the combinatorial theory of spherical varieties and a smoothness criterion of R. Camus to characterize the weight monoids of smooth affine spherical varieties.
Explicit formulae for averages of Goldbach representations
Authors: Brüdern Jörg , Kaczorowski Jerzy , Perelli Alberto
Published: January 2019

We prove an explicit formula, analogous to the classical explicit formula for

ψ
(
x
)

\psi (x)

, for the Cesàro–Riesz mean of any order

k
>
0

k>0

of the number of representations of

n
n

as a sum of two primes. Our approach is based on a double Mellin transform and the analytic continuation of certain functions arising therein.
On Riesz type inequalities for harmonic mappings on the unit disk
Authors: Kalaj David
Published: January 2019

We prove some sharp inequalities for complex harmonic functions on the unit disk. The results extend a M. Riesz conjugate function theorem and some well-known estimates for holomorphic functions. We apply some of results to the isoperimetric inequality for harmonic mappings.
Wronskians of Fourier and Laplace transforms
Authors: Dimitrov Dimitar , Xu Yuan
Published: January 2019

Associated with a given suitable function, or a measure, on

R

\mathbb {R}

, we introduce a correlation function so that the Wronskian of the Fourier transform of the function is the Fourier transform of the corresponding correlation function, and the same holds for the Laplace transform. We obtain two types of results. First, we show that Wronskians of the Fourier transform of a nonnegative function on

R

\mathbb {R}

are positive definite functions and that the Wronskians of the Laplace transform of a nonnegative function on

R

+

\mathbb {R}_+

are completely monotone functions. Then we establish necessary and sufficient conditions in order that a real entire function, defined as a Fourier transform of a positive kernel

K
K

, belongs to the Laguerre–Pólya class, which answers an old question of Pólya. The characterization is given in terms of a density property of the correlation kernel related to

K
K

, via classical results of Laguerre and Jensen and employing Wiener’s

L
1

L^1

Tauberian theorem. As a consequence, we provide a necessary and sufficient condition for the Riemann hypothesis in terms of a density of the translations of the correlation function related to the Riemann

ξ
\xi

-function.
A unified model for microtubule rescue
Authors: Fees Colby P. , Moore Jeffrey K.
Published: January 2019

How microtubules transition from depolymerization to polymerization, known as rescue, is poorly understood. Here we examine two models for rescue: 1) an “end-driven” model in which the depolymerizing end stochastically switches to a stable state; and 2) a “lattice-driven” model in which rescue sites are integrated into the microtubule before depolymerization. We test these models using a combination of computational simulations and in vitro experiments with purified tubulin. Our findings support the “lattice-driven” model by identifying repeated rescue sites in microtubules. In addition, we discover an important role for divalent cations in determining the frequency and location of rescue sites. We use “wash-in” experiments to show that divalent cations inhibit rescue during depolymerization, but not during polymerization. We propose a unified model in which rescues are driven by embedded rescue sites in microtubules, but the activity of these sites is influenced by changes in the depolymerizing ends.
Application of the Milan System for Reporting Salivary Gland Cytopathology: A Retrospective 12-Year Bi-institutional Study
Authors: Wu Howard H , Alruwaii Fatimah , Zeng Bao-Rung , Cramer Harvey M , Lai Chiung-Ru , Hang Jen-Fan
Published: January 2019

Objectives

Multi-institutional studies are required for the validation of the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC).

Methods

A total of 1,560 fine-needle aspirations of the salivary glands were retrieved from two institutions for a 12-year period. The diagnoses were reclassified based on the MSRSGC. Risk of malignancy (ROM) for each category was calculated based on 694 histologic follow-up cases.

Results

The ROM for each category was: 18.3% for nondiagnostic, 8.9% for nonneoplastic, 37.5% for atypia of undetermined significance (AUS), 2.9% for benign neoplasm, 40.7% for salivary gland neoplasm of uncertain malignant potential (SUMP), 100% for suspicious for malignancy, and 98.3% for malignant. The sensitivity, specificity, positive predictive rate, and negative predictive rates were 89%, 99%, 98%, and 96%, respectively.

Conclusions

The results of the current study are in keeping with the MSRSGC. The indeterminate categories of AUS and SUMP showed intermediate ROMs at 37.5% and 40.7%, respectively.
Evaluation of integrative clustering methods for the analysis of multi-omics data
Authors: Chauvel Cécile , Novoloaca Alexei , Veyre Pierre , Reynier Frédéric , Becker Jérémie
Published: January 2019

Recent advances in sequencing, mass spectrometry and cytometry technologies have enabled researchers to collect large-scale omics data from the same set of biological samples. The joint analysis of multiple omics offers the opportunity to uncover coordinated cellular processes acting across different omic layers. In this work, we present a thorough comparison of a selection of recent integrative clustering approaches, including Bayesian (BCC and MDI) and matrix factorization approaches (iCluster, moCluster, JIVE and iNMF). Based on simulations, the methods were evaluated on their sensitivity and their ability to recover both the correct number of clusters and the simulated clustering at the common and data-specific levels. Standard non-integrative approaches were also included to quantify the added value of integrative methods. For most matrix factorization methods and one Bayesian approach (BCC), the shared and specific structures were successfully recovered with high and moderate accuracy, respectively. An opposite behavior was observed on non-integrative approaches, i.e. high performances on specific structures only. Finally, we applied the methods on the Cancer Genome Atlas breast cancer data set to check whether results based on experimental data were consistent with those obtained in the simulations.
GRIMM: GRaph IMputation and matching for HLA genotypes
Authors: Maiers Martin , Halagan Michael , Gragert Loren , Bashyal Pradeep , Brelsford Jason , Schneider Joel , Lutsker Polina , Louzoun Yoram
Published: January 2019

Motivation

For over 10 years allele-level HLA matching for bone marrow registries has been performed in a probabilistic context. HLA typing technologies provide ambiguous results in that they could not distinguish among all known HLA alleles equences; therefore registries have implemented matching algorithms that provide lists of donor and cord blood units ordered in terms of the likelihood of allele-level matching at specific HLA loci. With the growth of registry sizes, current match algorithm implementations are unable to provide match results in real time.

Results

We present here a novel computationally-efficient open source implementation of an HLA imputation and match algorithm using a graph database platform. Using graph traversal, the matching algorithm runtime is practically not affected by registry size. This implementation generates results that agree with consensus output on a publicly-available match algorithm cross-validation dataset.

Availability and implementation

The Python, Perl and Neo4j code is available at https://github.com/nmdp-bioinformatics/grimm.

Supplementary information

Supplementary data are available at Bioinformatics online.
The way to analyse ‘way’: A case study in word-specific local grammar
Authors: Hanks Patrick , Može Sara
Published: January 2019

Traditionally, dictionaries are meaning-driven—that is, they list different senses (or supposed senses) of each word, but do not say much about the phraseology that distinguishes one sense from another. Grammars, on the other hand, are structure-driven: they attempt to describe all possible structures of a language, but say little about meaning, phraseology, or collocation. In both disciplines during the 20th century, the practice of inventing evidence rather than discovering it led to intermittent and unpredictable distortions of fact. Since 1987, attempts have been made in both lexicography (Cobuild) and syntactic theory (pattern grammar, construction grammar) to integrate meaning and phraseology. Corpora now provide empirical evidence on a large scale for lexicosyntactic description, but there is still a long way to go. Many cherished beliefs must be abandoned before a synthesis between empirical lexical analysis and grammatical theory can be achieved. In this paper, by empirical analysis of just one word (the noun way), we show how corpus evidence can be used to tackle the complexities of lexical and constructional meaning, providing new insights into the lexis-grammar interface.
Ideal Simplicial Volume of Manifolds with Boundary
Authors: Frigerio Roberto , Moraschini Marco
Published: January 2019

We define the ideal simplicial volume for compact manifolds with boundary. Roughly speaking, the ideal simplicial volume of a manifold $M$ measures the minimal size of possibly ideal triangulations of $M$ “with real coefficients”, thus providing a variation of the ordinary simplicial volume defined by Gromov in 1982, the main difference being that ideal simplices are now allowed to appear in representatives of the fundamental class. We show that the ideal simplicial volume is bounded above by the ordinary simplicial volume, and that it vanishes if and only if the ordinary simplicial volume does. We show that, for manifolds with amenable boundary, the ideal simplicial volume coincides with the classical one, whereas for hyperbolic manifolds with geodesic boundary it can be strictly smaller. We compute the ideal simplicial volume of an infinite family of hyperbolic $3$-manifolds with geodesic boundary, for which the exact value of the classical simplicial volume is not known, and we exhibit examples where the ideal simplicial volume provides sharper bounds on mapping degrees than the classical simplicial volume.
Perspectives of stakeholders on emergency obstetric care training in Kenya: a qualitative study
Authors: Banke-Thomas Aduragbemi , Maua Judith , Madaj Barbara , Ameh Charles , van den Broek Nynke
Published: January 2019

Background

This study explores stakeholders’ perceptions of emergency obstetric care (EmOC) ‘skills-and-drills’-type training including the outcomes, strengths, weaknesses, opportunities and threats of the intervention in Kenya.

Methods

Stakeholders who either benefited from or contributed to EmOC training were purposively sampled. Semi-structured topic guides were used for key informant interviews and focus group discussions. Following verbatim transcriptions of recordings, the thematic approach was used for data analysis.

Results

Sixty-nine trained healthcare providers (HCPs), 114 women who received EmOC and their relatives, 30 master trainers and training organizers, and six EmOC facility/Ministry of Health staff were recruited. Following training, deemed valuable for its ‘hands-on’ approach and content by HCPs, women reported that they experienced improvements in the quality of care provided. HCPs reported that training led to improved knowledge, skills and attitudes, with improved care outcomes. However, they also reported an increased workload. Implementing stakeholders stressed the need to explore strategies that help to maximize and sustain training outcomes.

Conclusions

The value of EmOC training in improving the capacity of HCPs and outcomes for mothers and newborns is not just ascribed but felt by beneficiaries. However, unintended outcomes such as increased workload may occur and need to be systematically addressed to maximize training gains.
The 112-Year Odyssey of Pertussis and Pertussis Vaccines—Mistakes Made and Implications for the Future
Authors: Cherry James D
Published: January 2019

Effective diphtheria, tetanus toxoids, whole-cell pertussis (DTwP) vaccines became available in the 1930s, and they were put into routine use in the United States in the 1940s. Their use reduced the average rate of reported pertussis cases from 157 in 100 000 in the prevaccine era to <1 in 100 000 in the 1970s. Because of alleged reactions (encephalopathy and death), several countries discontinued (Sweden) or markedly decreased (United Kingdom, Germany, Japan) use of the vaccine. During the 20th century, Bordetella pertussis was studied extensively in animal model systems, and many “toxins” and protective antigens were described. A leader in B pertussis research was Margaret Pittman of the National Institutes of Health/US Food and Drug Administration. She published 2 articles suggesting that pertussis was a pertussis toxin (PT)-mediated disease. Dr Pittman’s views led to the idea that less-reactogenic acellular vaccines could be produced. The first diphtheria, tetanus, pertussis (DTaP) vaccines were developed in Japan and put into routine use there. Afterward, DTaP vaccines were developed in the Western world, and definitive efficacy trials were carried out in the 1990s. These vaccines were all less reactogenic than DTwP vaccines, and despite the fact that their efficacy was less than that of DTwP vaccines, they were approved in the United States and many other countries. DTaP vaccines replaced DTwP vaccines in the United States in 1997. In the last 13 years, major pertussis epidemics have occurred in the United States, and numerous studies have shown the deficiencies of DTaP vaccines, including the small number of antigens that the vaccines contain and the type of cellular immune response that they elicit. The type of cellular response a predominantly, T2 response results in less efficacy and shorter duration of protection. Because of the small number of antigens (3–5 in DTaP vaccines vs >3000 in DTwP vaccines), linked-epitope suppression occurs. Because of linked-epitope suppression, all children who were primed by DTaP vaccines will be more susceptible to pertussis throughout their lifetimes, and there is no easy way to decrease this increased lifetime susceptibility.
EM counterparts of structured jets from 3D GRMHD simulations
Authors: Kathirgamaraju Adithan , Tchekhovskoy Alexander , Giannios Dimitrios , Barniol Duran Rodolfo
Published: January 2019

GW170817/GRB170817A has offered unprecedented insight into binary neutron star post-merger systems. Its Prompt and afterglow emission imply the presence of a tightly collimated relativistic jet with a smooth transverse structure. However, it remains unclear whether and how the central engine can produce such structured jets. Here, we utilize 3D general relativistic magnetohydrodynamic simulations starting with a black hole surrounded by a magnetized torus with properties typically expected of a post-merger system. We follow the jet, as it is self-consistently launched, from the scale of the compact object out to more than three orders of magnitude in distance. We find that this naturally results in a structured jet, which is collimated by the disc wind into a half-opening angle of roughly 10°; its emission can explain features of both the prompt and afterglow emission of GRB170817A for a 30° observing angle. Our work is the first to compute the afterglow, in the context of a binary merger, from a relativistic magnetized jet self-consistently generated by an accreting black hole, with the jet’s transverse structure determined by the accretion physics and not prescribed at any point.
OrthoMaM v10: Scaling-Up Orthologous Coding Sequence and Exon Alignments with More than One Hundred Mammalian Genomes
Authors: Scornavacca Celine , Belkhir Khalid , Lopez Jimmy , Dernat Rémy , Delsuc Frédéric , Douzery Emmanuel J P , Ranwez Vincent
Published: January 2019

We present version 10 of OrthoMaM, a database of orthologous mammalian markers. OrthoMaM is already 11 years old and since the outset it has kept on improving, providing alignments and phylogenetic trees of high-quality computed with state-of-the-art methods on up-to-date data. The main contribution of this version is the increase in the number of taxa: 116 mammalian genomes for 14,509 one-to-one orthologous genes. This has been made possible by the combination of genomic data deposited in Ensembl complemented by additional good-quality genomes only available in NCBI. Version 10 users will benefit from pipeline improvements and a completely redesigned web-interface.
Modern Training and Credentialing in Neuroendovascular Acute Ischemic Stroke Therapy
Authors: Schirmer Clemens M , Siddiqui Adnan H , Frid Ilya , Khalessi Alexander A , Mocco J , Griessenauer Christoph J , Goren Oded , Dalal Shamsher , Weiner Gregory , Arthur Adam S
Published: January 2019

BACKGROUND

Acute ischemic stroke (AIS) remains a significant source of morbidity and mortality worldwide. Multiple recent randomized clinical trials for AIS patients presenting with large vessel occlusion have demonstrated radical improvement in outcomes with mechanical thrombectomy (MT), which is now recognized as the new standard of care for patients presenting up to 24 hr.

OBJECTIVE

To provide a perspective on training and credentialing requirements for practitioners in this field.

METHODS

Relevant articles were systematically searched and analyzed. Standards for Reporting Qualitative Research guidelines were utilized.

RESULTS

: The Committee for Advanced Subspecialty Training (CAST) brings together the principal specialties of Radiology, Neurology, and Neurosurgery. Their training standards document the most recent consensus on training for neuroendovascular surgery (NES) and include the endovascular treatment of AIS as a part of the field of NES. This unified consensus represents a significant landmark in the evolution of stroke therapy. Presently, training at most centers follows an apprenticeship type model. Simulation methods and objective performance metrics have not been widely incorporated. Maintenance of proficiency has not been conclusively addressed reflecting the overall developing nature of the field.

CONCLUSION

The evolution of the standard of care interventional therapy for large vessel AIS utilizing MT raises concerns regarding work force needs, training standards, competency, and credentialing requirements for practitioners. The CAST framework represents the most modern and flexible approach for both individuals and training programs. Methods based on objective performance metrics utilizing simulation as primary vehicle may be the logical next steps in the evolution of NES.
Widespread Pressure Pain Sensitivity and Referred Pain from Trigger Points in Patients with Upper Thoracic Spine Pain
Authors: Ortega-Santiago Ricardo , Maestre-Lerga Maite , Fernández-de-las-Peñas César , Cleland Joshua A , Plaza-Manzano Gustavo
Published: January 2019

Objectives

The presence of trigger points (MTrPs) and pressure pain sensitivity has been well documented in subjects with neck and back pain; however, it has yet to be examined in people with upper thoracic spine pain. The purpose of this study was to investigate the presence of MTrPs and mechanical pain sensitivity in individuals with upper thoracic spine pain.

Methods

Seventeen subjects with upper thoracic spine pain and 17 pain-free controls without spine pain participated. MTrPs were examined bilaterally in the upper trapezius, rhomboid, iliocostalis thoracic, levator scapulae, infraspinatus, and anterior and middle scalene muscles. Pressure pain thresholds (PPTs) were assessed over T2, the C5-C6 zygapophyseal joint, the second metacarpal, and the tibialis anterior.

Results

The numbers of MTrPs between both groups were significantly different (P < 0.001) between patients and controls. The number of MTrPs for each patient with upper thoracic spine pain was 12.4 ± 2.8 (5.7 ± 4.0 active TrPs, 6.7 ± 3.4 latent TrPs). The distribution of MTrPs was significantly different between groups, and active MTrPs within the rhomboid (75%), anterior scalene (65%), and middle scalene (47%) were the most prevalent in patients with upper thoracic spine pain. A higher number of active MTrPs was associated with greater pain intensity and longer duration of pain history.

Conclusions

This study identified active MTrPs and widespread pain hypersensitivity in subjects with upper thoracic spine pain compared with asymptomatic people. Identifying proper treatment strategies might be able to reduce pain and improve function in individuals with upper thoracic spine pain. However, future studies are needed to examine this.
Health-related quality of life and its associated factors: results of a multi-center cross-sectional study among university students
Authors: Backhaus Insa , D’Egidio Valeria , Saulle Rosella , Masala Daniele , Firenze Alberto , De Vito Elisabetta , Mannocci Alice , La Torre Giuseppe
Published: January 2019

Background

The decline of health among university students represents an important and growing public health concern. Health problems and unhealthy lifestyle habits are common among many students, but factors influencing students’ health are not fully understood.

Methods

Italian university students from different study programs and curriculum years were asked to fill out a self-administered questionnaire, collecting data about age, gender, curriculum year, study program and health-related quality of life (QOL). Two latent factors were extracted: physical component summary score and mental component summary score. T-test, one-way ANOVA, multivariate and age and sex-stratified analyses were performed.

Results

Students scored relatively poor on health-related QOL, with an overall mental component summary score of 41,3% (± 10,0) and physical component summary score of 52,9% (±6,0), with significantly higher mental component summary score for male students (P = < 0,005). Studying economics, law (b = −2,513, P = 0,007) or engineering (b = −2,762; P = 0,001) was associated to negatively influence students’ health.

Conclusions

Factors such as study program are associated with health-related QOL. Further longitudinal studies assessing additional socio-demographic factors are needed to fully assess what influences students’ health. Students’ health should be at the top of the agenda of public health researchers, academic supervisors and policy-makers.
Antimicrobial prescribing in older adults
Authors: Brandburg Gloria L.
Published: January 2019

Infectious diseases pose a significant threat to older adult health and well-being. Determining the appropriate use and selection of antimicrobials in older adults can be challenging. Age-related physiologic changes, multiple comorbidities, and polypharmacy are factors that can make prescribing antimicrobials complicated and the effectiveness of therapy unpredictable.
Quality improvement initiatives in rheumatology: an integrative review of the last 5 years
Authors: Liu Lucy H. , Choden Sonam , Yazdany Jinoos
Published: January 2019

Purpose of review

We reviewed recent quality improvement initiatives in the field of rheumatology to identify common strategies and themes leading to measurable change.

Recent findings

Efforts to improve quality of care in rheumatology have accelerated in the last 5 years. Most studies in this area have focused on interventions to improve process measures such as increasing the collection of patient-reported outcomes and vaccination rates, but some studies have examined interventions to improve health outcomes. Increasingly, researchers are studying electronic health record (EHR)-based interventions, such as standardized templates, flowsheets, best practice alerts and order sets. EHR-based interventions were most successful when reinforced with provider education, reminders and performance feedback. Most studies also redesigned workflows, distributing tasks among clinical staff. Given the common challenges and solutions facing rheumatology clinics under new value-based payment models, there are important opportunities to accelerate quality improvement by building on the successful efforts to date. Structured quality improvement models such as the learning collaborative may help to disseminate successful initiatives across practices.

Review of recent quality improvement initiatives in rheumatology demonstrated common solutions, particularly involving leveraging health IT and workflow redesign.
The Association Between the Classification of Early-onset Scoliosis and Smith Complications After Initiation of Growth-friendly Spine Surgery: A Preliminary Study
Authors: Russo Christen , Trupia Evan , Campbell Megan , Matsumoto Hiroko , Smith John , Samdani Amer , Emans John , Roye David , Vitale Michael
Published: January 2019

Background:

Early-onset scoliosis (EOS) is a complex, heterogeneous condition involving multiple etiologies, genetic associations, and treatment plans. In 2014, Williams and colleagues proposed a classification system of EOS (C-EOS) that categorizes patients by etiology, Cobb angle, and kyphosis. Shortly after, Smith and colleagues validated a classification system to report complications of growth-friendly spine instrumentation. Severity refers to the level of care and urgency required to treat the complication, and can be classified as device-related or disease-related complications. The purpose of this study was to investigate if C-EOS can be used as a reliable predictor of Smith complications to better risk stratify these young, surgical patients.

Methods:

This study queried retrospective data from a large multicenter registry with regard to growth-friendly spine instrumentation in the EOS population. One-hundred sixteen patients were included in final data analysis to investigate the outcomes of their growth-friendly procedures according to the Smith complication classification system.

Results:

There were 245 Smith complications distributed among 116 patients included in this study (2.1 complications per patient). The majority of the complications were device related requiring at least one unplanned trip to the operating room (Smith Device Complication IIA or IIB; 111 complications). There were no complications that caused abandonment of growth-friendly instrumentation (Smith Complication III) and no mortalities (Smith Complication IV). The most severely affected EOS group was the hyperkyphotic syndromic group with a major curve angle >50 degrees (S3+), with 3.4 complications per patient. The least affect EOS group was the hyperkyphotic congenital group with a major curve angle between 20 and 50 degrees, with 0.3 complications per patient.

Conclusions:

The C-EOS simplifies a complex pathology and the Smith complication classification scheme creates a language to discuss treatment of known complications of growth-friendly spine surgery. Although there is an association between more advanced C-EOS and Smith complications, there does not appear to be a correlation that can satisfy a risk stratification at this time.

Level of Evidence:

Level II.