bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal tracking performance for SIMO systems with packet dropouts and control energy constraints
Authors: Jiang Xiao‐Wei , Chen Chao‐Yang , Yang Qing‐Sheng , Qu Xiu‐Jun , Yan Huai‐Cheng
Published: April 2018

In this study, the optimal tracking performance for single‐input multiple‐output (SIMO) systems under control energy constraints is investigated. The packet dropouts in the upstream channel and down channel are adequately considered. The minimal tracking error is obtained by searching through all stablising controllers. The main results of this study show that the optimal tracking performance in these kinds of system is closely dependent on the structure of the given plant and statistic characteristics of the reference signal. Furthermore, the packet dropouts in the communication channel will degenerate the tracking performance. Finally, a typical example is given to illustrate the theoretical results.
Two‐stage unscented Kalman filter algorithm for fault estimation in spacecraft attitude control system
Authors: Chen Xueqin , Sun Rui , Wang Feng , Song Daozhe , Jiang Wancheng
Published: April 2018

The study of fault/bias estimation based on the two‐stage Kalman filter and the unscented Kalman filter in the presence of unknown random biases is addressed. Two kinds of faults are taken into account: additive faults and multiplicative faults, which are modelled as actuator faults and sensor faults in the spacecraft attitude control system (ACS). In accordance with the characteristic of the fault model of ACS, where the system state and the faults are decoupled, a novel two‐stage unscented Kalman filter (TSUKF) algorithm is developed to estimate the decoupled states and biases simultaneously. By employing the unscented transform, the TSUKF algorithm does not need any linearisation of non‐linear system models or the augmentation of the state, contributing to a more precise estimation. Meanwhile the computational cost is reduced by exploiting the bias‐separate principle. The simulation results demonstrate the proposed algorithm when a micro‐spacecraft is tracking a stable/manoeuvring target.
Survey on various lane and driver detection techniques based on image processing for hilly terrain
Authors: Manoharan Kodeeswari , Daniel Philemon
Published: April 2018

As vehicular traffic continues to grow traffic management and prevention of accidents has become a major concern. This problem only gets magnified when travel on the mountainous roads are considered. This study is especially focused toward Himalayan mountains as they pose a greater risk because of their rugged natural setting. This study investigates crucial problems faced on the hilly roads and the challenges in translating existing driver‐assistance systems to such roads. The survey probes every lane detection algorithms, image processing techniques and various assistance features for applicability to hilly roads discussing the pros and cons for each of them. Conclusions are drawn as to deduce the more suitable methods that can be improvised and re‐tuned to adapt them for mountainous roads.
LASR-guided stellar photometric variability subtraction
Authors: Ahlers John P. , Barnes Jason W. , Horvath Sarah A. , Myers Samuel A. , Hedman Matthew M.
Published: April 2018

We develop a technique for removing stellar variability in the light curves of δ-Scuti and similar stars. Our technique, which we name the Linear Algorithm for Significance Reduction (LASR), subtracts oscillations from a time series by minimizing their statistical significance in frequency space. We demonstrate that LASR can subtract variable signals of near-arbitrary complexity and can robustly handle close frequency pairs and overtone frequencies. We demonstrate that our algorithm performs an equivalent fit as prewhitening to the straightforward variable signal of KIC 9700322. We also show that LASR provides a better fit to seismic activity than prewhitening in the case of the complex δ-Scuti KOI-976.
Nuclear versus integrated spectroscopy of galaxies in the Herschel Reference Survey
Authors: Gavazzi G. , Consolandi G. , Belladitta S. , Boselli A. , Fossati M.
Published: April 2018

Context. The determination of the relative frequency of active galactic nuclei (AGN) versus other spectral classes, for example, HII region-like (HII), transition objects (TRAN), passive (PAS), and retired (RET), in a complete set of galaxies in the local Universe is of primary importance to discriminate the source of ionization in the nuclear region of galaxies (e.g., supermassive black holes vs. young and old stars).

Aims. Here we aim to provide a spectroscopic characterization of the nuclei of galaxies belonging to the Herschel Reference Survey (HRS), a volume and magnitude limited sample representative of the local Universe, which has become a benchmark for local and high-z studies, for semianalytical models and cosmological simulations. The comparison between the nuclear spectral classification and the one determined on the global galactic scale provides information about how galaxy properties change from the nuclear to the outer regions. Moreover, the extrapolation of the global star formation (SF) properties from the SDSS fiber spectroscopy compared to the one computed by Hα photometry can be useful for testing the method based on aperture correction for determining the global star formation rate for local galaxies.

Methods. By collecting the existing nuclear spectroscopy available from the literature, complemented with new observations obtained using the Loiano 1.52 m telescope, we analyze the 322 nuclear spectra of HRS galaxies; their integrated spectroscopy is available from the literature as well.

Results. Using two diagnostic diagrams (the BPT and the WHAN) we provide a nuclear and an integrated spectral classification for the HRS galaxies. The BPT and the WHAN methods for nuclei consistently give a frequency of 53–64% HII, around 21–27% AGNs (including TRAN), and 15–20% of PAS (including RET), whereas for integrated spectra they give 69–84% HII, 4–11% of AGNs and 12–20% PAS. Solely among late-type galaxies (LTGs) do the nuclear percentages become 67–77% HII, 22–27% AGNs (including TRAN), and only 1–7% of PAS. For the integrated spectra these frequencies become: 80–85% HII, 9–11% AGNs and 4–9% PAS.

Conclusions. We find that the fraction of HII region-like spectra is strongly anticorrelated with the stellar mass. On the contrary the frequency of AGNs increases significantly with stellar mass, such that at M* > 1010.0 M⊙~ 66% of the LTGs are AGNs or TRAN. Moreover there is not a significant dependence of the frequency of AGNs as a function of environment: AGNs+TRAN above 109.0 M⊙ are consistent with ~30% irrespective of their membership to the Virgo cluster, suggesting that the AGNs population is not sensitive to the environment. Finally, extrapolation of the global SF properties from the nuclear spectroscopy including aperture corrections leads to underestimates with respect to values derived from direct integrated Hα photometry.
Die Schuleingangsuntersuchung: Ein kritischer Blick auf Historie und Status quo
Authors: Wattjes Anja , Karathana Maria , Krackhardt Bernhard , Heudorf Ursel
Published: April 2018

In Deutschland wurde bereits Ende des 19. Jahrhunderts die Untersuchung der Schulanfänger, die Schuleingangsuntersuchung, etabliert. Lag zunächst der Fokus auf dem Ausschluss von Infektionserkrankungen und Gesundheitsproblemen, die den Schulbesuch erschweren könnten bzw. sich im Lauf des Schulbesuchs verschlechtern könnten, trat Mitte des 20. Jahrhunderts das Konzept der Schulreife in den Vordergrund. Dabei wurden unterschiedliche „Schulreife-Konzepte“ angewandt, die inzwischen wieder verlassen wurden, da sie einer Evaluation nicht standhielten. Inzwischen wurde auch das Konzept der „Schulreife“ durch das Konzept der „Schulfähigkeit“ ersetzt. Es stellt sich nicht mehr die Frage, ob, sondern mit welchen Hilfen und welcher Förderung ein Kind einzuschulen ist. Heute umfasst die Schuleingangsuntersuchung in praktisch allen Bundesländern neben einer Anamnese die Erfassung des Vorsorge- und des Impfstatus, einen Seh- und Hörtest sowie als besonderen Schwerpunkt die Beurteilung der Entwicklung der Kinder und des individuellen Förderbedarfs– insbesondere im Bereich der Visuomotorik, der Kognition und der Sprache. In fast allen Bundesländern macht die Schuleingangsuntersuchung einen Großteil der Arbeit des Kinder- und Jugendärztlichen Dienstes aus und bindet erhebliche Ressourcen. In der vorliegenden Arbeit wird dies kritisch diskutiert und ein Diskurs angeregt, ob diese Ressourcen nicht zielführender im Sinne der Kindergesundheit eingesetzt werden sollten angesichts geänderter gesellschaftlicher Bedingungen wie der in vielen Bundesländern verpflichtenden Wahrnehmung der Kinder-Vorsorgeuntersuchungen, der Zunahme von Seiteneinsteigenden aus anderen Ländern, insbesondere auch von Asylsuchenden, oder der Inklusion mit Schließung der Förderschulen und den damit verbundenen großen Herausforderungen in den Regelschulen.
High-resolution photoluminescence electro-modulation microscopy by scanning lock-in
Authors: Koopman W. , Muccini M. , Toffanin S.
Published: April 2018

Morphological inhomogeneities and structural defects in organic semiconductors crucially determine the charge accumulation and lateral transport in organic thin-film transistors. Photoluminescence Electro-Modulation (PLEM) microscopy is a laser-scanning microscopy technique that relies on the modulation of the thin-film fluorescence in the presence of charge-carriers to image the spatial distribution of charges within the active organic semiconductor. Here, we present a lock-in scheme based on a scanning beam approach for increasing the PLEM microscopy resolution and contrast. The charge density in the device is modulated by a sinusoidal electrical signal, phase-locked to the scanning beam of the excitation laser. The lock-in detection scheme is achieved by acquiring a series of images with different phases between the beam scan and the electrical modulation. Application of high resolution PLEM to an organic transistor in accumulation mode demonstrates its potential to image local variations in the charge accumulation. A diffraction-limited precision of sub-300 nm and a signal to noise ratio of 21.4 dB could be achieved.
A soft switching with reduced voltage stress ZVT-PWM full-bridge converter
Authors: Sahin Yakup , Ting Naim Suleyman , Acar Fatih
Published: April 2018

This paper introduces a novel active snubber cell for soft switching pulse width modulation DC-DC converters. In the proposed converter, the main switch is turned on under zero voltage transition and turned off under zero voltage switching (ZVS). The auxiliary switch is turned on under zero current switching (ZCS) and turned off under zero current transition. The main diode is turned on under ZVS and turned off under ZCS. All of the other semiconductors in the converter are turned on and off with soft switching. There is no extra voltage stress on the semiconductor devices. Besides, the proposed converter has simple structure and ease of control due to common ground. The detailed theoretical analysis of the proposed converter is presented and also verified with both simulation and experimental study at 100 kHz switching frequency and 600 W output power. Furthermore, the efficiency of the proposed converter is 95.7% at nominal power.
Fractal nature of aluminum alloys substructures under creep and its implications
Authors: Fernández R. , Bruno G. , González-Doncel G.
Published: April 2018

The present work offers an explanation for the variation of the power-law stress exponent, n, with the stress σ normalized to the shear modulus G in aluminum alloys. The approach is based on the assumption that the dislocation structure generated with deformation has a fractal nature. It fully explains the evolution of n with σ/G even beyond the so-called power law breakdown region. Creep data from commercially pure Al99.8%, Al-3.85%Mg, and ingot AA6061 alloy tested at different temperatures and stresses are used to validate the proposed ideas. Finally, it is also shown that the fractal description of the dislocation structure agrees well with current knowledge.
Rotor boundary layer development with inlet guide vane (IGV) wake impingement
Authors: Jia Lichao , Zou Tengda , Zhu Yiding , Lee Cunbiao
Published: April 2018

This paper examines the transition process in a boundary layer on a rotor blade under the impingement of an inlet guide vane wake. The effects of wake strengths and the reduced frequency on the unsteady boundary layer development on a low-speed axial compressor were investigated using particle image velocimetry. The measurements were carried out at two reduced frequencies (fr = fIGVS0/U2i, fr = 1.35, and fr = 0.675) with the Reynolds number, based on the blade chord and the isentropic inlet velocity, being 97 500. At fr = 1.35, the flow separated at the trailing edge when the wake strength was weak. However, the separation was almost totally suppressed as the wake strength increased. For the stronger wake, both the wake’s high turbulence and the negative jet behavior of the wake dominated the interaction between the unsteady wake and the separated boundary layer on the suction surface of the airfoil. The boundary layer displacement thickened first due to the negative jet effect. Then, as the disturbances developed underneath the wake, the boundary layer thickness reduced gradually. The high disturbance region convected downstream at a fraction of the free-stream velocity and spread in the streamwise direction. The separation on the suction surface was suppressed until the next wake’s arrival. Because of the long recovery time at fr = 0.675, the boundary layer thickened gradually as the wake convected further downstream and finally separated due to the adverse pressure gradient. The different boundary layer states in turn affected the development of disturbances.
Electric field-induced resistive switching, magnetism, and photoresponse modulation in a Pt/Co0.03Zn0.97O/Nb:SrTiO3 multi-function heterostructure
Authors: Luo Zhipeng , Pei Ling , Li Meiya , Zhu Yongdan , Xie Shuai , Cheng Xiangyang , Liu Jiaxian , Ding Huaqi , Xiong Rui
Published: April 2018

A Co0.03Zn0.97O (CZO) thin film was epitaxially grown on a Nb doped (001) SrTiO3 (NSTO) single-crystal substrate by pulsed laser deposition to form a Pt/CZO/NSTO heterostructure. This device exhibits stable bipolar resistive switching, well retention and endurance, multilevel memories, and a resistance ratio of high resistance state (HRS)/low resistance state (LRS) up to 7 × 105. Under the illumination of a 405 nm laser, the HRS of the device showed distinct photoelectricity with an open-circuit voltage of 0.5 V. A stronger ferromagnetism was observed at the HRS than at the LRS. The above phenomenon is attributable to the accumulation and migration of oxygen vacancies at the interface of CZO/NSTO. Our results demonstrated a pathway towards making multifunctional devices that simultaneously exhibit resistive switching, photoelectricity, and ferromagnetism.
Carrier-selective interlayer materials for silicon solar cell contacts
Authors: Xue Muyu , Islam Raisul , Chen Yusi , Chen Junyan , Lu Ching-Ying , Mitchell Pleus A. , Tae Christian , Xu Ke , Liu Yi , Kamins Theodore I. , Saraswat Krishna C. , Harris James S.
Published: April 2018

This work presents titanium oxide (TiOx) and nickel oxide (NiOx) as promising carrier-selective interlayer materials for metal-interlayer–semiconductor contacts for silicon solar cells. The electron-conducting, hole-blocking behavior of TiOx and the opposite carrier-selective behavior of NiOx are investigated using the transmission-line-method. The Fermi level depinning effect and the tunneling resistance are demonstrated to be dependent on the interlayer oxide thickness and annealing temperature. NiOx is furthermore experimentally demonstrated to be capable of improving the effective minority carrier lifetime by quasi-steady-state photoconductance method. Our study demonstrates that TiOx and NiOx can be effective carrier-selective materials for Si solar cells and provides a framework for characterizing carrier-selective contacts.
Error analysis of multi-needle Langmuir probe measurement technique
Authors: Barjatya Aroh , Merritt William
Published: April 2018

Multi-needle Langmuir probe is a fairly new instrument technique that has been flown on several recent sounding rockets and is slated to fly on a subset of QB50 CubeSat constellation. This paper takes a fundamental look into the data analysis procedures used for this instrument to derive absolute electron density. Our calculations suggest that while the technique remains promising, the current data analysis procedures could easily result in errors of 50% or more. We present a simple data analysis adjustment that can reduce errors by at least a factor of five in typical operation.
Positron scattering from pyridine
Authors: Stevens D. , Babij T. J. , Machacek J. R. , Buckman S. J. , Brunger M. J. , White R. D. , García G. , Blanco F. , Ellis-Gibbings L. , Sullivan J. P.
Published: April 2018

We present a range of cross section measurements for the low-energy scattering of positrons from pyridine, for incident positron energies of less than 20 eV, as well as the independent atom model with the screening corrected additivity rule including interference effects calculation, of positron scattering from pyridine, with dipole rotational excitations accounted for using the Born approximation. Comparisons are made between the experimental measurements and theoretical calculations. For the positronium formation cross section, we also compare with results from a recent empirical model. In general, quite good agreement is seen between the calculations and measurements although some discrepancies remain which may require further investigation. It is hoped that the present study will stimulate development of ab initio level theoretical methods to be applied to this important scattering system.
Experimental and theoretical study of the C4 defect in neutron irradiated silicon
Authors: Londos C. A. , Aliprantis D. N. , Antonaras G. , Potsidi M. S. , Angeletos T.
Published: April 2018

This work reports infrared spectroscopy studies in neutron irradiated Cz-Si containing carbon. The material was thermally treated at high temperature prior to irradiation. The aim was to investigate the production and annealing of the CiOi(SiI) defect, well-known as C4 center. Besides the two standard localized vibrational modes (LVMs) at 934 and 1018 cm−1 detected always in room temperature measurements, another band was also detected at 760 cm−1. The latter band has the same annealing behavior as the 934 and 1018 cm−1 bands. Its existence has been predicted by theoretical calculations previously, but it has not been reported definitely so far experimentally. The present study verifies unambiguously its presence. Upon annealing the above three bands begin to decay in the spectra at ∼140 °C and disappear at ∼200 °C. No other bands appear to arise in the spectra upon the disappearance of the above bands. Semi-empirical calculations of the LVM frequencies of the C4 complex verify the correlation of the 760 cm−1 band with this center. The annealing kinetics of the bands was investigated, and it was found that their decay follows a second order reaction with an average activation energy of E ∼ 0.50 ± 0.02 eV.
First principles calculations provide a defect phase diagram for gallium oxide
Authors: DeJarnette Drew
Published: April 2018

New theoretical development suggests gallium oxide as a semiconductor material could be more ubiquitous by establishing phase diagrams over a wide variety of dopants and processing conditions to suppress defect states for high quality operation.
A fractal explanation for creep in aluminum
Authors: Wolverton Mark
Published: April 2018

A fractal description of dislocation structures in aluminum alloys leads to effective modeling of creep phenomena and explains power law stress evolution and variation.
Subspecies definitions and legislation: from eastern wallaroo (Osphranter robustus robustus) to euro (Osphranter robustus erubescens)
Authors: Richardson Barry J.
Published: April 2018

As a consequence of genetic studies of population structuring, the usefulness of subspecies has been questioned, with opinions divided. The situation is further confused by the use of varying species and subspecies concepts. Most alternatives require each taxon to be following an independent evolutionary trajectory. These include traditional approaches and the more recent phylogenetic species concept. The latter has led to large increases in the apparent number of taxa in some groups, though strong objections have been raised to this approach. An alternative, the ecological species concept, has been opposed by phylogeneticists. These two approaches are compared using morphological and genetic data from common wallaroo (Osphranter robustus) populations. The different taxonomies that might result (many species, one species with two subspecies, one species with no subspecies) can have significant consequences for legislative and management decisions. The ecological approach is considered preferable for subspecies and the present taxonomy is maintained. A potential location of the boundary between the wallaroo subspecies is proposed. How the use of the different subspecies definitions would affect legislative decisions is explored.
Seed germination of tangled lignum (Duma florulenta) and nitre goosefoot (Chenopodium nitrariaceum) under experimental hydrological regimes
Authors: Higgisson William , Briggs Sue , Dyer Fiona
Published: April 2018

The distribution of plants on flood plains depends on the hydrological regime on the flood plain and the hydrological requirements of the plants. The aims of the present study were to: (1) determine the relationships between germination of tangled lignum (Duma florulenta) and nitre goosefoot (Chenopodium nitrariaceum) and hydrological regime; (2) determine the buoyancy of the seeds of the two species, and hence the ability of the seeds to disperse by water; and (3) inform environmental flow requirements for the two species. Seeds of tangled lignum germinated best on soaked soil and on soil inundated for 20 days. Seeds of nitre goosefoot germinated best on soil inundated for 5 days and on soaked soil. The majority of tangled lignum seeds floated for at least 7 days. The majority of nitre goosefoot seeds sank within 7 days. The results of the present study are consistent with the observed distributions of the species on flood plains. Tangled lignum requires ~20 days of flooding and wet soils following flood recession for optimal germination. Nitre goosefoot requires a few days of flooding and wet soils following flood recession for optimal germination. The inundation requirements for germination of tangled lignum and nitre goosefoot should be considered in the management of environmental flows.
Widespread changes in transcriptome profile of human mesenchymal stem cells induced by two-dimensional nanosilicates
Authors: Carrow James K. , Cross Lauren M. , Reese Robert W. , Jaiswal Manish K. , Gregory Carl A. , Kaunas Roland , Singh Irtisha , Gaharwar Akhilesh K.
Published: April 2018

Significance

We demonstrate the use of next-generation sequencing technology (RNA-seq) to understand the effect of a two-dimensional nanomaterial on human stem cells at the whole-transcriptome level. Our results identify more than 4,000 genes that are significantly affected, and several biophysical and biochemical pathways are triggered by nanoparticle treatment. We expect that this systematic approach to understand widespread changes in gene expression due to nanomaterial exposure is key to develop new bioactive materials for biomedical applications.
Dynamic visits of cortical structures probe for cell size
Authors: Gerganova Veneta , Martin Sophie G.
Published: April 2018

All cells show size homeostasis owing to coordination of division with growth. In this issue, Allard et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201709171) establish that transient inhibitory visits of a negative regulator of Cdk1 to cortical oligomeric platforms increase in number and duration with cell growth, suggesting how Cdk1 activation is coupled to cell size.
Expression of mutant Asxl1 perturbs hematopoiesis and promotes susceptibility to leukemic transformation
Authors: Nagase Reina , Inoue Daichi , Pastore Alessandro , Fujino Takeshi , Hou Hsin-An , Yamasaki Norimasa , Goyama Susumu , Saika Makoto , Kanai Akinori , Sera Yasuyuki , Horikawa Sayuri , Ota Yasunori , Asada Shuhei , Hayashi Yasutaka , Kawabata Kimihito Cojin , Takeda Reina , Tien Hwei-Fang , Honda Hiroaki , Abdel-Wahab Omar , Kitamura Toshio
Published: April 2018

Additional sex combs like 1 (ASXL1) is frequently mutated in myeloid malignancies and clonal hematopoiesis of indeterminate potential (CHIP). Although loss of ASXL1 promotes hematopoietic transformation, there is growing evidence that ASXL1 mutations might confer an alteration of function. In this study, we identify that physiological expression of a C-terminal truncated Asxl1 mutant in vivo using conditional knock-in (KI) results in myeloid skewing, age-dependent anemia, thrombocytosis, and morphological dysplasia. Although expression of mutant Asxl1 altered the functions of hematopoietic stem cells (HSCs), it maintained their survival in competitive transplantation assays and increased susceptibility to leukemic transformation by co-occurring RUNX1 mutation or viral insertional mutagenesis. KI mice displayed substantial reductions in H3K4me3 and H2AK119Ub without significant reductions in H3K27me3, distinct from the effects of Asxl1 loss. Chromatin immunoprecipitation followed by next-generation sequencing analysis demonstrated opposing effects of wild-type and mutant Asxl1 on H3K4me3. These findings reveal that ASXL1 mutations confer HSCs with an altered epigenome and increase susceptibility for leukemic transformation, presenting a novel model for CHIP.
Effect of Lime Stabilization on Vertical Deformation of Laterite Halmahera Soil
Authors: Saing Zubair , Djainal Herry
Published: April 2018

In this paper, the study was conducted to determine the lime effect on vertical deformation of road base physical model of laterite Halmahera soil. The samples of laterite soil were obtained from Halmahera Island, North Maluku Province, Indonesia. Soil characteristics were obtained from laboratory testing, according to American Standard for Testing and Materials (ASTM), consists of physical, mechanical, minerals, and chemical. The base layer of physical model testing with the dimension; 2m of length, 2m of width, and 1.5m of height. The addition of lime with variations of 3, 5, 7, an 10%, based on maximum dry density of standard Proctor test results and cured for 28 days. The model of lime treated laterite Halmahera soil with 0,1m thickness placed on subgrade layer with 1,5m thickness. Furthermore, the physical model was given static vertical loading. Some dial gauge is placed on the lime treated soil surface with distance interval 20cm, to read the vertical deformation that occurs during loading. The experimentals data was analyzed and validated with numerical analysis using finite element method. The results showed that the vertical deformation reduced significantly on 10% lime content (three times less than untreated soil), and qualify for maximum deflection (standard requirement L/240) on 7-10% lime content.
The Cellular Second Fundamental Theorem of Invariant Theory for Classical Groups
Authors: Bowman Christopher , Enyang John , Goodman Frederick M
Published: April 2018

We construct explicit integral bases for the kernels and the images of diagram algebras (including the symmetric groups, orthogonal and symplectic Brauer algebras) acting on tensor space. We do this by providing an axiomatic framework for studying quotients of diagram algebras.
Barriers and Facilitators to Self-Directed Learning in Continuing Professional Development for Physicians in Canada: A Scoping Review
Authors: Jeong Dahn , Presseau Justin , ElChamaa Rima , Naumann Danielle N. , Mascaro Colin , Luconi Francesca , Smith Karen M. , Kitto Simon
Published: April 2018

Purpose

This scoping review explored the barriers and facilitators that influence engagement in and implementation of self-directed learning (SDL) in continuing professional development (CPD) for physicians in Canada.

Method

This review followed the six-stage scoping review framework of Arksey and O’Malley and of Daudt et al. In 2015, the authors searched eight online databases for English-language Canadian articles published January 2005–December 2015. To chart and analyze data from the 17 included studies, they employed a two-step analysis process composed of conventional content analysis followed by directed coding applying the Theoretical Domains Framework (TDF).

Results

Conventional content analysis generated five categories of barriers and facilitators: individual, program, technological, environmental, and workplace/organizational. Directed coding guided by the TDF allowed analysis of barriers and facilitators to behavior change according to two key groups: physicians engaging in SDL, and SDL developers designing and implementing SDL programs. Of the 318 total barriers and facilitators coded, 290 (91.2%) were coded for physicians and 28 (8.8%) for SDL developers. The majority (209; 65.7%) were coded in four key TDF domains: environmental context and resources, social influences, beliefs about consequences, and behavioral regulation.

Conclusions

This scoping review identified five categories of barriers and facilitators in the literature and four key TDF domains where most factors related to behavior change of physicians and SDL developers regarding SDL programs in CPD were coded. There was a significant gap in the literature about factors that may contribute to SDL developers’ capacity to design and implement SDL programs in CPD.
Social Accountability: A Framework for Medical Schools to Improve the Health of the Populations They Serve
Authors: Rourke James
Published: April 2018

Social accountability has gained importance and greater acceptance in the ever-increasing complexity and interconnectivity of patient care, education, and research that is the threefold mission of academic health science centers and networks. In this Invited Commentary, the author provides a brief overview of the development of the concept of social accountability and the criteria for the Association for Medical Education in Europe ASPIRE-to-Excellence Award for Social Accountability, which provide a useful framework for medical schools to consider when examining their own social accountability. Per these criteria, schools are expected to document social accountability plans in their organization and functions; document social accountability actions in their education and research program activities; and demonstrate positive impacts of their education, research, service, graduates, and partnerships on the health care and health of their community, region, and nation. Award-winning schools integrate social accountability into the school’s mission, planning, and day-to-day management. The health needs and diversity of the school’s community, region, and nation are reflected in the school’s admissions, curriculum, learning experiences, research activities, health care partnerships, and graduates. The author also describes three award winners as exemplars of social accountability and concludes by challenging every medical school and graduate medical education program to focus on meeting the needs of the populations it serves, especially those who are marginalized, vulnerable, and underserved.
Outpatient Posterior Lumbar Fusion
Authors: Arshi Armin , Park Howard Y. , Blumstein Gideon W. , Wang Christopher , Buser Zorica , Wang Jeffrey C. , Shamie Arya N. , Park Don Y.
Published: April 2018

Study Design.

A retrospective case-control study.

Objective.

The aim of this study was to determine the nationwide trends and complication rates associated with outpatient posterior lumbar fusion (PLF).

Summary of Background Data.

Outpatient lumbar spine fusion is now possible secondary to minimally invasive techniques that allow for reduced hospital stays and analgesic requirements. Limited data are currently available regarding the clinical outcome of outpatient lumbar fusion.

Methods.

The Humana administrative claims database was queried for patients who underwent one to two-level PLF (CPT-22612 or CPT-22633 AND ICD-9–816.2) as either outpatients or inpatients from Q1 2007 to Q2 2015. The incidence of perioperative medical and surgical complications was determined by querying for relevant International Classification of Diseases and Current Procedural Terminology codes. Multivariate logistic regression adjusting for age, gender, and Charlson Comorbidity Index was used to calculate odds ratios (ORs) of complications among outpatients relative to inpatients undergoing PLF.

Results.

Cohorts of 770 patients who underwent outpatient PLF and 26,826 patients who underwent inpatient PLF were identified. The median age was in the 65 to 69 years age group for both cohorts. The annual relative incidence of outpatient PLF remained stable across the study period (R
2 = 0.03, P = 0.646). Adjusting for age, gender, and comorbidities, patients undergoing outpatient PLF had higher likelihood of revision/extension of posterior fusion [(OR 2.33, confidence interval (CI) 2.06–2.63, P < 0.001], anterior fusion (OR 1.64, CI 1.31–2.04, P < 0.001), and decompressive laminectomy (OR 2.01, CI 1.74–2.33, P < 0.001) within 1 year. Risk-adjusted rates of all other postoperative surgical and medical complications were statistically comparable.

Conclusion.

Outpatient lumbar fusion is uncommonly performed in the United States. Data collected from a national private insurance database demonstrate a greater risk of postoperative surgical complications including revision anterior and posterior fusion and decompressive laminectomy. Surgeons should be cautious in performing PLF in the outpatient setting, as the risk of revision surgery may increase in these cases.

Level of Evidence: 3
Ascorbic Acid Attenuates Multifidus Muscles Injury and Atrophy After Posterior Lumbar Spine Surgery by Suppressing Inflammation and Oxidative Stress in a Rat Model
Authors: Tang Pan , Zhu Ren , Gu Yu , Gu Jia-Ming , Xie Zi-Ang , Xu Jia-Qi , Zhao Xiang-De , Huang Kang-Mao , Wang Ji-Ying , Jiang Xue-Sheng , Fan Shun-Wu , Hu Zhi-Jun
Published: April 2018

Study Design.

A rat model of multifidus muscles injury and atrophy after posterior lumbar spine surgery.

Objective.

We determined the effect of ascorbic acid (AA) on the postoperative multifidus muscles in rat model.

Summary of Background Data.

Previous studies show oxidative stress and inflammation are two main molecular mechanisms in multifidus muscle injury and atrophy after posterior lumbar surgery. AA may have a protective effect in postoperative multifidus muscles.

Methods.

Rats were divided into sham surgery, control surgery, and surgery plus AA groups. Multifidus muscles of the control and AA groups were excised from the osseous structures. The muscles were retracted continuously for 2 hours. In the sham and AA groups, AA was administered via oral gavage daily in the first week. In each group, the oxidative stress was evaluated by measuring malondialdehyde (MDA) and Total superoxide dismutase (T-SOD). The inflammation, fat degeneration, or fibrosis of multifidus muscle were evaluated by quantitative real-time polymerase chain reaction (q-PCR), histology, or immunohistochemical analysis.

Results.

T-SOD activity was significantly lower in the control group than that in the AA group in the first week. MDA levels were significantly higher in the AA group. Interleukin-6 and tumor necrosis factor-α in multifidus muscles also showed significant differences when treated with AA. The inflammation score on histology was significantly lower in the AA group postoperatively in the first week. In the long run, marker genes for fibrosis and fat degeneration, and fibrosis and fat degeneration scores, were significantly lower in the AA than the control group on days 14 and 28 postoperatively.

Conclusion.

In conclusion, AA attenuated the oxidative stress and inflammation response in the postoperative multifidus muscles, and remarkable differences were observed from the histological assessment and related marker genes expression. Our results provided important insight into the anti-inflammatory and anti-oxidative effects of AA in the postoperative multifidus muscles.

Level of Evidence: N/A
Posterior Shoulder Dislocation Associated With the Head (Splitting) and Humeral Neck Fracture: Impact of Understanding Radiologic Signs and Experience With an Extended Deltopectoral Approach
Authors: Gokkus Kemal , Sagtas Ergin , Kara Hasan , Aydin Ahmet T.
Published: April 2018

In this paper, our main objective was to emphasize the competency of extended deltopectoral exposure, enforced with the supraspinatus and subscapularis detachment, to gain access to the entire head. The second important point in this paper was to underline the importance of the knowledge that is necessary for interpreting classic radiologic signs of posterior fracture-dislocation of the shoulder. A 47-year-old woman fell down directly onto her shoulder while she was skiing. She was diagnosed with posterior shoulder dislocation, associated with fracture of the head (head splitting) and humeral neck fracture, with the aid of plain radiographs and computed tomographic results. The patient was treated with open reduction and internal fixation of the fracture, through the extended deltopectoral approach, which was augmented with rotator cuff detachment. At the 1-year follow-up, x-rays showed stable fixation with good evidence of healing. One year after the surgery, the patient had no pain, and she regained most of her functionality in her right shoulder with 140 to 150 degrees of lateral elevation (abduction), 140 to 150 degrees of forward flexion , internal rotation hand at T12 vertebra (slightly restricted). These results showed good functionality, with a painless shoulder at the 1-year follow-up. The “double shadow” and “lightbulb” signs are indicative of posterior shoulder fracture-dislocation, and augmented (with the detachment of supraspinatus and subscapularis tendons) traditional deltopectoral incision is suitable for managing these kinds of difficult fracture dislocations.
Temporary Bridge Plate Stabilization of Unstable Elbow Fractures and Dislocations
Authors: Edelman David , Ilyas Asif M.
Published: April 2018

Unstable fracture-dislocations of the elbow, and in particular the “terrible triad” injury consisting of an elbow dislocation with a fracture of the radial head and coronoid, are complex injuries that can be plagued and complicated by persistent instability. Acute and chronic instability is a difficult problem and is best managed early by avoidance and restoration of stability. A number of treatment options have been proposed to manage acute postfixation instability of the elbow joint. Traditional stabilization options include immobilization with splinting or casting, cross-articular pinning, and external fixation (hinged or static), followed by early physical therapy. However, each of these approaches can still yield persistent elbow instability. We are proposing a new technique of acute but temporary bridge plate stabilization of the elbow joint to protect the concentrically reduced elbow joint following repair of all injured structures to restore stability followed by staged removal and the delayed initiation of therapy.
Estimation of Extra Length of Stay Attributable to Hospital-Acquired Infections in Adult ICUs Using a Time-Dependent Multistate Model*
Authors: Ohannessian Robin , Gustin Marie-Paule , Bénet Thomas , Gerbier-Colomban Solweig , Girard Raphaele , Argaud Laurent , Rimmelé Thomas , Guerin Claude , Bohé Julien , Piriou Vincent , Vanhems Philippe
Published: April 2018

Objectives:

The objective of the study was to estimate the length of stay of patients with hospital-acquired infections hospitalized in ICUs using a multistate model.

Design:

Active prospective surveillance of hospital-acquired infection from January 1, 1995, to December 31, 2012.

Setting:

Twelve ICUs at the University of Lyon hospital (France).

Patients:

Adult patients age greater than or equal to 18 years old and hospitalized greater than or equal to 2 days were included in the surveillance. All hospital-acquired infections (pneumonia, bacteremia, and urinary tract infection) occurring during ICU stay were collected.

Interventions:

None.

Measurements and Main Results:

The competitive risks of in-hospital death, transfer, or discharge were considered in estimating the change in length of stay due to infection(s), using a multistate model, time of infection onset. Thirty-three thousand four-hundred forty-nine patients were involved, with an overall hospital-acquired infection attack rate of 15.5% (n = 5,176). Mean length of stay was 27.4 (± 18.3) days in patients with hospital-acquired infection and 7.3 (± 7.6) days in patients without hospital-acquired infection. A multistate model–estimated mean found an increase in length of stay by 5.0 days (95% CI, 4.6–5.4 d). The extra length of stay increased with the number of infected site and was higher for patients discharged alive from ICU. No increased length of stay was found for patients presenting late-onset hospital-acquired infection, more than the 25th day after admission.

Conclusions:

An increase length of stay of 5 days attributable to hospital-acquired infection in the ICU was estimated using a multistate model in a prospective surveillance study in France. The dose-response relationship between the number of hospitalacquired infection and length of stay and the impact of early-stage hospital-acquired infection may strengthen attention for clinicians to focus interventions on early preventions of hospital-acquired infection in ICU.
Modernizing the Mohs Surgery Consultation: Instituting a Video Module for Improved Patient Education and Satisfaction
Authors: Newsom Emily , Lee Erica , Rossi Anthony , Dusza Stephen , Nehal Kishwer
Published: April 2018

BACKGROUND

Studies show that patients recall less than half of the information given by their physicians. Use of video in medicine increases patient comprehension and satisfaction and decreases anxiety. However, studies have not elaborated on video content.

OBJECTIVE

To use principles of learning with multimedia to improve the Mohs surgery consultation.

MATERIALS AND METHODS

The authors developed 2 informational videos on Mohs surgery: traditional versus narrative. The focus of the traditional video was purely didactic. The narrative video included patient testimonials, patient–physician interaction, and animations. New Mohs surgery patients viewed either the traditional (n = 40) or the narrative video (n = 40). Existing Mohs surgery patients (n = 40) viewed both videos. Both groups answered questionnaires about their satisfaction.

RESULTS

For new Mohs surgery patients, no significant difference was found between the traditional and the narrative video groups because respondent satisfaction was high for both video formats. For existing Mohs surgery patients, all respondents (100%) reported that videos were helpful for understanding Mohs surgery; however, the majority would recommend the narrative over the traditional format (72.5% vs 27.5%, p = .01).

CONCLUSION

Technology is useful for patient education because all patients preferred seeing a video to no video. Further research is needed to optimize effective multimedia use in patient education.
Effect of Diallyl Trisulfide on Ischemic Tissue Injury and Revascularization in a Diabetic Mouse Model
Authors: Yang Hai-Bing , Liu Hui-Min , Yan Jin-Chuan , Lu Zhao-Yang
Published: April 2018

Background and Objective:

Allitridin [diallyl trisulfide (DATS)] is an extract from garlic (Allium sativum) that putatively improves endothelial function and is protective against cardiovascular diseases. Endothelial dysfunction after tissue ischemia in diabetic patients is partially due to poor angiogenic response. This study investigated whether DATS may improve angiogenesis in a diabetic mouse model with hind limb ischemia.

Methods:

Streptozotocin was administered by intraperitoneal injection to establish the model of diabetes in male C57BL/6 mice. After 14 days, nondiabetic and diabetic mice (n = 24, each) underwent unilateral hind limb ischemia by femoral artery ligation. The mice were apportioned to 4 groups: nondiabetic treated (or not) with DATS and diabetic treated (or not) with DATS. DATS treatment consisted of a single daily intraperitoneal injection of 500 μg·kg−1·d−1 for 14 days, beginning on the day of induced ischemia. Ischemia was scored by standard criteria. Blood perfusion was determined using thermal infrared imaging. Tissue capillary density and oxidative stress levels were measured by immunohistochemistry and immunofluorescence, respectively. Serum lipids were measured by enzymatic colorimetric assay. Fasting serum insulin was detected using an insulin enzyme-linked immunosorbent assay kit. Nitric oxide (NO) metabolites and protein carbonyls in tissues were determined by enzyme-linked immunosorbent assay. Targeted protein concentrations were measured by western blotting.

Results:

At 14 days after ligation, the ischemic skeletal muscle of the streptozotocin-induced diabetic mice had lower levels of endothelial NO synthase, phosphorylated endothelial NO synthase, and vascular endothelial growth factor compared with nondiabetic group. In addition, the hind limb blood perfusion, capillary density, and NO bioactivity were lower in the diabetic group, whereas oxidative stress and protein carbonyl levels were higher. These changes were ameliorated by DATS treatment.

Conclusions:

DATS treatment of diabetic mice promoted revascularization in ischemic tissue.
The Impact of Behavioral and Psychological Factors on Physical Fitness in Medical and Nursing Students
Authors: FitzGerald Leah Z. , Boland David
Published: April 2018

Physical activity improves general health and quality of life. A stressful academic environment can increase both physical and mental health disruptions in medical and nursing students, negatively impacting physical activity and fitness. We explored the relationship between the fitness profiles of 202 medical and graduate nursing students with self-reported levels of general and emotional health to elucidate the role of the psychosocial factors involved in choosing to exercise.