bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental assessment of alluviation downstream of Hun-lock, Belgium
Authors: Swartenbroekx Catherine , Savary Céline , Bousmar Didier
Published: September 2018

To maintain inland navigation, a deposition crest in the Hunlock area, in the Upper Meuse River, Belgium, has to be dredged almost every two years. A long-term solution is searched for, based on the understanding of water velocity field and solid transport processes, to avoid the silting and the expensive dredging. The physical process is analysed thanks to a 1:50 small-scale model of the 500 m-long Meuse reach with Hun movable dam as upstream boundary. The velocity fields, recorded with an electromagnetic probe displaced automatically, are compared for several configurations. Three discharges and distinct dam openings are tested in the existing configuration. Modifications of the downstream guard wall, by perforating ports, are also considered. Building groynes in the right side of the river is analysed. Finally, flushing water through the lock is tested. As conclusions, alluviations are due to the localisation of the lock in an enlarged area of the Upper Meuse and in a meander intrados, inducing decreasing flow velocities. None of the tested solutions is completely convincing according to 4 criterions: (1) ability to decrease the deposition crest, (2) navigation requirements, (3) safety in case of high-stage discharges, and (4) acceptable cost.
Two-dimensional Pollutant Transport Simulations in Natural Streams with Horizontal Recirculation Zone
Authors: Park Inhwan , Seong Hoje , Kim Hyung-jun , Rhee Dong Sop
Published: September 2018

In this study, flow and pollutant transport simulations were conducted in the tidal reach of the Han River where the horizontal recirculation zone induced by the tidal cycle causes the storage effect. The flow analysis results show that the flow direction was repeatedly changed due to the downstream water level and the horizontal recirculation zone was occurred at the point where the flow direction was changed. Thus, the pollutant cloud was advected back and forth by the periodically occurred reversal flow. The storage effects of the horizontal recirculation zone cause that the concentration-time curve shows oscillatory increasing patterns, and the retention time of pollutant cloud was also increased.
Three-dimensional simulation of non-uniform sediment transport based on multi-phase Eulerian approach: Application to debris flow
Authors: Ota Kazuyuki , Suto Hitoshi , Sato Takahiro
Published: September 2018

To simulate 3D flow of a non-uniform and highly concentrated sediment, a numerical model using a multi-phase Eulerian method for air, water, and particles of various class size is developed. This model accounts for turbulence in pore water, particle-particle collisions, and enduring friction. To test its performance, simulations were performed for large scale debris-flow experiments. The numerical model reproduces successfully the flow property and sediment size segregation of the debris flow.
On experimental censorship of particle hops in bed-load transport
Authors: Ballio Francesco , Fathel Siobhan L. , Furbish David Jon , Radice Alessio
Published: September 2018

Observation of incomplete particle hops in imaging-based experiments with bed-load transport does not just occur with hops that are longer than an area of observation. Even short hops can be in fact incompletely measured if they cross the boundaries of the focus area. Experimental censorship biases the statistical distribution and moments of bed-load particle hops. This paper presents: a theoretical quantification of an expected effect of experimental censorship; based on this quantification, a method to correct the statistical distribution of hop lengths; an application of the method to experimental data. Applying the correction leads to significantly different values of the mean hop length, compensating the biasing effect of censorship. By contrast, nothing can be done for experimental truncation that is associated with hops longer than an applied area of observation. Experimental truncation must be avoided a priori, by appropriate design of the measurement method.
Turbulent structure inside and above shallow to deep canopies
Authors: Chagot Loïc , Moulin Frédéric , Eiff Olivier , Elyakime Pierre
Published: September 2018

Multi-plane PIV measurements were performed in an open-channel flume filled with elongated prisms of height k and width l to investigate the effect of the deepening of the canopy on the flow structure. Velocity measurements were performed both inside the canopy and above it. Analysis of the spatial convergence for the double-averaged quantities shows that for canopy flow investigations (z < k), at least 5 measurement planes are required to obtain a relative spatial convergence error below 3% for the dispersive shear stress, the quantity the most sensible to spatial sampling. With only three measurement planes, the spatial convergence is below 1% only in the flow region above the canopy (z > k). Three canopy aspect ratios, k/l = [1, 3, 6] were investigated for a fixed modified-submergence ratio β = (h - k)=l = 3 where h is the water depth. As the canopy deepens, the hydraulic roughness decreases and the velocity near the bottom of the canopy becomes gradually constant, as expected for deep canopies. We show how the highly converged (both in space and time) profiles of double-averaged longitudinal velocity and total shear stress can be used to calculate the vertical distribution of drag in the canopy. With this methodology, values of the drag coefficient CD(z) can be calculated, and are found to be always close to unity, even in the upper part of the canopy.
Depth-averaged velocity and bed shear stress in unsteady open channel flow over rough bed
Authors: Khuntia Jnana Ranjan , Devi Kamalini , Proust Sebastien , Khatua Kishanjit Kumar
Published: September 2018

Very few studies have been carried out in the past in estimating depth-averaged velocity and bed shear stress in unsteady flow over rough beds. An experiment is thus conducted to investigate the vertical and lateral velocity profiles under unsteady flow conditions in a rough open channel for various flow depths. One hydrogram is repeatedly passed through the rectangular flume with a fixed rigid grass bed. Using micro Pitot tube and Acoustic Doppler Velocimeter (ADV), the flow patterns are investigated at both lateral and longitudinal positions over different cross-sections. For two typical flow depths, the velocities in both the rising limb and falling limb are observed. Hysteresis effect between stage-discharge (h ~ Q) rating curve between rising and falling limbs is illustrated. Lateral distribution of depth-averaged velocity and bed shear stress are plotted at three different cross sections and compared with the steady flow conditions. In falling limb of an unsteady flow case, both depth-averaged velocity and bed shear stress distribution in the central region is higher than that of steady flow case. However, in the rising limb, the bed shear stress of unsteady flow is less than that of steady flow case. Further, in an unsteady flow, the magnitude of depth-averaged velocity is found to increase towards the downstream sections. Along the downstream positions, bed shear stress values increase for lower flow depths and decrease for higher flow depth cases.
Estimating the long-term evolution of river bed levels using hydrometric data
Authors: Le Coz Jérôme , Smart Graeme , Hicks Murray , Mansanarez Valentin , Renard Benjamin , Camenen Benoît , Lang Michel
Published: September 2018

The stage-discharge measurements and rating curves accumulated over decades at hydrometric stations are a valuable source of information on the long-term evolution of river bed levels. However, the methodology to extract meaningful geomorphic information from such hydrometric data is not straightforward. We introduce an original method to estimate the parameters of successive rating curves by Bayesian analysis in sequence. These parameters reflect the physical properties of the channel features that control the stage-discharge relation: low-flow riffles, main channel, floodway (bars), floodplain, etc. The dates of rating changes are assumed to be known in existing hydrometric records. The uncertainty interval of each parameter is estimated, assuming, however, that no rating change has been ignored by the station manager. It is thus possible to clearly distinguish overall trends of the channel bed level from the local evolution of riffles and to evaluate whether the observed temporal changes are significant compared to the estimation uncertainties.
Development of Aerial Space Time Volume Velocimetry for Measuring Surface Velocity Vector Distribution from UAV
Authors: Tsuji Issei , Tani Kojiro , Fujita Ichiro , Notoya Yuichi
Published: September 2018

Due to the remarkable development of unmanned aerial vehicle (UAV) in recent years, its application in river engineering increases widely mainly for the measurement of ground topography such as by the technique Structure from Motion (SfM) using a series of high-resolution static images. However, although UAV usually installed a high density video camera, the use of the movie is limited just for watching and observing the geometrical feature of the ground. In the light of such a present status, the authors have developed an aerial space-time image velocimetry (STIV) technique to measure streamwise river surface velocity distributions. However, as STIV is insensitive to the change of flow direction, the aerial space-time volume velocimetry (STVV) technique, which is an extension of STIV, was developed in this research. STVV examines the change of volumetric texture within a space-time volume (STV) instead of examining the change of image intensity on a line segment as in STIV. The performance of STVV was investigated during the measurement of snowmelt flood of the Shinano River by comparing it with those obtained by the other techniques such as STIV, LSPIV and ADCP. It was made clear the aerial STVV has a great advantage over the existing image-based techniques.
Numerical study of building drag dissipation for- mulations in the integral porosity shallow water model
Authors: Ilhan Özgen , Bruwier Martin , Zhao Jiaheng , Liang Dongfang , Archambeau Pierre , Dewals Benjamin , Kobayashi Kenichiro , Oishi Satoru , Hinkelmann Reinhard
Published: September 2018

The integral porosity shallow water model is a type of porous shallow water model for urban flood modeling, that defines two types of porosity, namely a volumetric porosity inside the computational cell and a conveyance porosity at each edge. Porosity terms are determined directly from the underlying building geometry, hence buildings do not need to be discretized exactly. This enables simulations with significantly reduced CPU time on meshes with cell sizes larger than the building size. Here, the macroscopic model view leads to an additional source term at the unresolved building-fluid interface, yielding a building drag dissipation source term. In literature, several formulations for this term can be found. The integral porosity shallow water model is sensitive to the building drag dissipation, and using the drag parameters as a calibration parameter enhances the accuracy of model results. However, the ideal way to achieve this is still an open research question. In this contribution, we present a simple technique to estimate building drag dissipation that uses the conveyance porosity configuration to estimate the projected area inside the cell, which is then used in a drag force equation. The advantage of this approach is that it is computationally inexpensive, no additional parameters need to be stored, and only a single parameter has to be calibrated. The proposed approach is compared with drag dissipation formulations from existing literature in a laboratory experiment that features a dam-break against an isolated obstacle. The aim of the comparison is to evaluate present existing building drag dissipation models with regard to accuracy and computational cost.
Investigation of distributed-porosity fields for urban flood modelling using single-porosity models
Authors: Soares-Frazão Sandra , Franzini Fabian , Linkens Jérémy , Snaps Jean-Charles
Published: September 2018

Porosity-based model rely on the assumption that an urban area can be compared to a porous medium, where the porosity is defined as the ratio between the actual area available to the flow, i.e. not occupied by buildings, and the total area of the considered urban environment. In classical single-porosity models, the resulting value of the porosity parameter is considered as constant and accounts essentially for the reduced water storage capacity and reduced space available for the flow. As a consequence, the source term involving the porosity parameter only accounts for a local head loss at the entrance and at the exit of the urban area. Therefore, the head losses occurring inside the urban area are accounted for using drag-type source terms. In the present work, we tested different definitions of the porosity parameter, showing the benefits of accounting for areas with distributed porosity based on the actual layout of buildings and streets. This formulation is still compatible with the basic idea of porosity-based model, i.e allowing for the use of coarse computational meshes instead of refined meshing of the urban area.
Analytical solution of non-uniform flow in compound channel
Authors: Devi Kamalini , Das Bhabani S. , Khuntia Jnana R. , Khatua Kishanjit K.
Published: September 2018

The present work investigates the analysis of depth-averaged velocity and boundary shear stress distribution in compound channels with non-uniform flow condition. A quasi two-dimensional model is proposed to assess the flow variables by accounting the physical processes that are specific to non-uniform flow. For analyzing the flow behavior, experimental data sets concerning compound channels with narrowing and enlarging floodplains of previous investigators are considered. The model accounts the influence of momentum transfer on the flow variables through additional shear stresses that are developed in non-uniform flow. Three types of effective stresses produced by molecular viscosity, turbulent and dispersion on the vertical planes are discussed. An analytical solution to the model is presented. Terms associated with the effective stresses are investigated relating them to the geometric and hydraulic parameters. The significance of lateral variation of energy slope is further investigated. For both homogenous and heterogeneous non-prismatic channels, the approach is examined to predict the flow variables with reasonable accuracy.
An analytical solution for flow estimation of a meandering compound channel
Authors: Pradhan Arpan , Kumar Khatua Kishanjit
Published: September 2018

An analytical model is proposed to determine the discharge capacity in a meandering compound channel. The channel cross-section is divided into four sub-sections, such as the lower main channel, the floodplain within the meander belt and the two outer floodplains. Momentum transfer in-between these four subsections is taken into consideration in the analytical model. The model basically determines the force balance of each individual subsection to predict its mean velocity and thereby the sub-sectional discharge. The paper suggests a non-dimensional parameter, αT, which is the momentum transfer coefficient, that is determined to be unique for each individual channel. The paper deals with the calibration of this parameter for both largescale and small-scale data sets.
Begleitung von Frauen mit Kinderwunschbehandlung
Authors: Wollenschlaeger Lisa , Stamm Anja
Published: September 2018

Immer mehr Paare, die lange glücklos versucht haben, ein Kind zu zeugen, nehmen medizinische Hilfe in Anspruch. Eine Kinderwunschbehandlung ist manchmal der einzige Weg, schwanger zu werden. Vor welche Herausforderungen das die Frau stellt, welche Auswirkungen es auf die Schwangerschaft haben kann und was diesen Frauen hilft, beschreiben Hebamme und Kinderwunschberaterin Lisa Wollenschlaeger und eine von ihr begleitete Mutter.
Palliative chirurgische Therapieoptionen beim kastrationsresistenten Prostatakarzinom
Authors: Haidl Friederike , Heidenreich Axel
Published: September 2018

LHRH-Analoga oder Antagonisten stellen das Mittel der Wahl beim metastasierten Prostatakarzinom dar. Trotz anfänglich meist guten Ansprechens hat diese Therapie nur einen palliativen Charakter und führt unweigerlich nach durchschnittlich 1,5 bis 2,5 Jahren zur Entwicklung eines kastrationsresistenten Prostatakarzinoms (KRPCA). In diesem Fall stehen neben der klassischen Taxan-basierten Chemotherapie, die sekundäre Hormonablation mit Enzalutamid und Abirateron, Sipuleucel T sowie Radium 223 als neuere Therapieverfahren zur Verfügung. Aufgrund der dadurch – je nach Therapieansprechen – verlängerten Überlebenszeit gewinnen behandlungswürdige Komplikationen durch das lokal progrediente KRPCA, Lokalrezidive oder pelvine Lymphknotenmetasen zunehmend an Bedeutung. Treten Komplikationen des unteren Harntrakts wie rezidivierende transfusionspflichtige Makrohämaturien mit oder ohne Blasentamponade, eine subvesikale Obstruktion mit der Notwendigkeit einer Harnableitung oder rektourethrale/rektovesikale Fisteln auf, stehen als palliative chirurgische Therapieoptionen die palliative TUR-P, die radikale (Zysto-) Prostatektomie mit entsprechender Harnableitung sowie die posteriore Exenteration bei rektaler Infiltration zur Verfügung. Bei Harnstauungsnieren aufgrund einer supravesikalen Obstruktion stehen je nach Erlebenserwartung und Allgemeinzustand des Patienten die Anlage einer endoluminalen Ureterschiene oder perkutanen Nephrostomie sowie chirurgisch rekonstruktive Maßnahmen wie die Ureterneoimplantation, Ureter-Ileum-Interponat oder Implantation eines Detour®-Systems als Therapieoptionen zur Verfügung.

Letztlich stellt die palliative Tumorchirurgie ein individuelles Therapiekonzept dar, welches bei sorgfältiger Patientenselektion und adäquater chirurgischer Expertise zu einer Verbesserung der Lebensqualität und lokalen Tumorkontrolle führen kann.
Patrón sensibilidad/resistencia en los urocultivos de pacientes con I.T.U. que consultan a urgencias de adultos, Hospital de San José entre enero de 2014 y diciembre de 2014
Authors: Ibañez Diego Armando Riatiga , Rojas Adriana Jiménez , Sánchez Luis Eduardo Salgado , Fernández Fernando Enrique Gaona , Madarriaga Yesica Yasmín Quiroz
Published: September 2018

Introducción: La infección del tracto urinario (ITU) es un motivo de consulta frecuente en urgencias, siendo necesario el tratamiento antibiótico empírico antes de obtener un urocultivo.

Objetivo Determinar el patrón de sensibilidad/resistencia de los gérmenes aislados en los urocultivos de pacientes que ingresan por urgencias de adultos con sintomatología sugestiva de ITU.

Métodos Se realizó un estudio observacional, descriptivo de corte transversal, recolectando los datos de los urocultivos de pacientes con diagnóstico de ITU que asistieron por urgencias adultos, y cumplieron los criterios de inclusión en el año 2014.

Resultados Se analizaron 133 pacientes (133 urocultivos), 50,4% mujeres, edad promedio de 64,1 años (DE 19,1). Se encontró una frecuencia mayor de ITU alta (54,9%), e ITU no complicada (54,1%), la mayoría de origen en la comunidad (95,5%). El germen más frecuentemente aislado fue E. coli (56,4%), seguido por Klebsiella oxytoca (7,1%). La resistencia de E. coli fue del 55,7% para ampicilina sulbactam, 58,2% para nitrofurantoina, 40% para quinolonas y 32% para cefazolina. En pacientes con factores de riesgo urológico se encontró una resistencia entre el 40% al 50%. Se evidenció patrón BLEA (12,9%), AMPc (20%) y KPC (1,4%).

Conclusión Los uropatógenos han aumentado de forma significativa su resistencia a las diferentes familias de antibióticos, entre ellas las cefalosporinas y las quinolonas, confirmando que medicamentos como ampicilina sulbactam, nitrofurantoina, y ciprofloxacina no están indicados en el manejo empírico de ITU en nuestra institución, especialmente al presentar factores de riesgo urológicos.
The fatty acid composition of ewe milk or suckling lamb meat can be used to discriminate between ewes fed different diets
Authors: Lobón S. , Joy M. , Sanz A. , Álvarez-Rodríguez J. , Blanco M.
Published: September 2018

Thirty-nine ewe-lamb pairs were used to evaluate the effects of the diet of lactating ewes, the type of forage (pasture vs hay) and the inclusion of 10% quebracho in the concentrate on the fatty acid (FA) profile of their milk and the meat of their suckling lambs. The estimated forage–concentrate ratio was 80:20. Milk from pasture ewes had a higher percentage of saturated FAs (SFAs; 62.3 vs 56.5), lower percentages of monounsaturated FAs (MUFAs; 30.4 vs 36.6) and n-6 polyunsaturated FAs, and a lower n-6:n-3 ratio (1.9 vs 2.3) than did that of hay ewes (P < 0.001). Meat of pasture lambs had higher percentages of total polyunsaturated FAs (PUFAs; 23.0 vs 20.4; P < 0.05) and n-3 (7.0 vs 5.0; P < 0.001) and lower percentages of MUFAs (37.9 vs 41.8; P < 0.001) and n-6:n-3 (2.0 vs 2.8; P < 0.001) than did that of hay lambs. The inclusion of quebracho increased MUFAs in milk (P < 0.05) and decreased SFAs in meat (P < 0.05). Ewes were correctly classified to the different treatments by using the FA profile of milk (100% score outcome), and to a lesser extend by using the FA profile of lamb (82–100% score outcome); de novo synthesis of FAs in lamb muscle might have reduced the classification accuracy. In conclusion, forage type had a greater effect on the FA profiles of ewe milk and the meat of suckling lambs than did the inclusion of quebracho in the concentrate. To improve the classification of meat of suckling lamb, other biomarkers should be examined. These results are relevant for ewes farmed for the production of milk as well as lambs.
Oxygen effect on structural and optical properties of zinc oxide
Authors: Radjehi Lamia , Djelloul Abdelkader , Lamri Salim , Slim Mohamed Fares , Rahim Mourad
Published: September 2018

This article deals with an investigation of the effect of oxygen content on optical and structural properties of ZnO films. Zinc oxide films were deposited with the DC reactive magnetron sputtering process on Si(100) and glass substrates. ZnO films were elaborated at different oxygen flow rates from (O2) 12 to 35 sccm. The evolution of optical and structural properties as a function of O2 was investigated by X-ray diffraction, Profilometer, Field Emission Scanning Electron Microscopy (FESEM) and ultraviolet–visible. By increasing O2, the crystallite size increases from 20 to 27 nm, which leads to an enlargement in the ZnO band gap from 3.18 to 3.30 eV. At 30 sccm of O2, the films present a significant improvement in the band gap (3.30 eV). The results reveal that with increasing O2, all films show a high crystallinity in the wurtzite phase and present a (002)ZnO preferential orientation along the c-axis. ZnO exhibited a good self-texture.
The Effects of Ambulatory Blood Pressure Monitoring on Sleep Quality in Men and Women With Hypertension: Dipper vs. Nondipper and Race Differences
Authors: Sherwood Andrew , Hill LaBarron K , Blumenthal James A , Hinderliter Alan L
Published: September 2018

BACKGROUND

The nondipping circadian blood pressure (BP) profile is associated with both poor sleep quality and increased cardiovascular risk. The present study aimed to clarify the potential confounding effects of 24-hour ambulatory blood pressure monitoring (ABPM) used to characterize the circadian BP profile by assessing its impact on sleep quality.

METHODS

Participants were 121 middle-aged men and women with untreated hypertension (age = 46 ± 8 years; 43% women; 45% African-American). Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index. Wrist actigraphy was used to measure sleep quality objectively as sleep efficiency (SE) and total sleep time (TST) on 7 consecutive non-ABPM days (baseline) and 3 subsequent 24-hour ABPM days.

RESULTS

Average ambulatory BP was 137.2 ± 10.8/84.3 ± 8.5 mm Hg during the day and 119.6 ± 12.4/69.5 ± 9.8 mm Hg at night. Using the criterion of <10% dip in systolic BP (SBP) to define nondippers, there were 40 nondippers (SBP dip = 7.3 ± 2.6%) and 81 dippers (SBP dip = 15.5 ± 3.4%). There was no effect of time on SE or TST over non-ABPM and ABPM days, suggesting that ABPM does not adversely affect sleep quality. Sleep quality was generally poorer (lower SE) in nondippers compared with dippers (P = 0.033), but differences were independent of whether or not participants were undergoing 24-hour ABPM. African-American race (P = 0.002) was also associated with lower SE.

CONCLUSION

Sleep quality generally appears to be poor in men and women with untreated hypertension and especially among African-Americans. Importantly, for both dippers and nondippers, we found no evidence that ABPM had an adverse effect on sleep quality.
Homology and Specificity of Natural Sound-Encoding in Human and Monkey Auditory Cortex
Authors: Erb Julia , Armendariz Marcelo , De Martino Federico , Goebel Rainer , Vanduffel Wim , Formisano Elia
Published: September 2018

Understanding homologies and differences in auditory cortical processing in human and nonhuman primates is an essential step in elucidating the neurobiology of speech and language. Using fMRI responses to natural sounds, we investigated the representation of multiple acoustic features in auditory cortex of awake macaques and humans. Comparative analyses revealed homologous large-scale topographies not only for frequency but also for temporal and spectral modulations. In both species, posterior regions preferably encoded relatively fast temporal and coarse spectral information, whereas anterior regions encoded slow temporal and fine spectral modulations. Conversely, we observed a striking interspecies difference in cortical sensitivity to temporal modulations: While decoding from macaque auditory cortex was most accurate at fast rates (> 30 Hz), humans had highest sensitivity to ~3 Hz, a relevant rate for speech analysis. These findings suggest that characteristic tuning of human auditory cortex to slow temporal modulations is unique and may have emerged as a critical step in the evolution of speech and language.
Measuring fisheries performance using the “Goldilocks plot”
Authors: Hilborn Ray
Published: September 2018

Most reporting of stock status accumulated at a national or regional level gives statistics on what proportion of the stocks are below some abundance threshold or above some fishing mortality rate threshold. This approach does not convey useful information on the performance of the fisheries management system in maximizing long-term sustainable yield, which is the primary objective of most national and international fisheries legislation. In this paper, I present a graphical approach for representing how much yield is being lost as a consequence of current suboptimal abundance and fishing pressure. Using the EU stocks assessed by ICES as an example, I show how traditional criteria for overfished and overfishing fail to display realistic information about the performance of the fishery. This approach provides much more useful information for the public and policy makers.
Accuracy and Safety of Lateral Vertebral Notch-Referred Technique Used in Subaxial Cervical Pedicle Screw Placement
Authors: Pan Zhimin , Zhong Junlong , Xie Shiming , Yu Limin , Wu Chunyang , Ha Yoon , Kim Keung Nyun , Zhang Youshan , Cao Kai
Published: September 2018

BACKGROUND

Biomechanical studies revealed that pedicle screw instrumentation has a superior stabilizing effect compared with other internal fixations in reconstructing the subaxial cervical spine. However, severe neurovascular risks preclude surgeons from routinely conducting pedicle screw manipulation in cervical spine.

OBJECTIVE

To evaluate the accuracy and safety of the lateral vertebral notch (LVN)-referred technique used in subaxial cervical pedicle screw (CPS) placement.

METHODS

One hundred thirty-five consecutive retrospective patients with cervical disorders underwent the LVN-referred technique for CPS placements in 3 spine centers. Postoperative pedicle perforations were confirmed by CT scans to assess the technical accuracy. Neurovascular complications derived from CPS misplacements were recorded to evaluate the technical safety.

RESULTS

A total of 718 CPSs were inserted into subaxial cervical spine. Postoperative CT scans revealed that the accuracy of CPS placement was superior. Neither vertebral artery injury nor spinal cord injury occurred. One radiculopathy was from a unilateral C6 nerve root compression. A screw-related neurovascular injury rate of 0.7% occurred in this cohort. Additionally, there was no significant difference in the accuracy of CPS placement among 3 surgeons (H = 1.460, P = .482). The relative standard deviation values revealed that technical reproducibility was acceptable. Furthermore, there was no significant difference between the patients’ pedicle transverse angles and inserted CPS transverse angles from C3 to C7 (all P > .05).

CONCLUSION

The LVN is a reliable and consistent anatomic landmark for CPS placement. The accuracy and safety of subaxial CPS placement by using LVN-referred technique are highly acceptable, which may endow this technique to be practicably performed in selected patients.
Employing a Root Cause Analysis Process to Improve Examination Quality
Authors: Santen Sally A. , Grob Karri L. , Monrad Seetha U. , Stalburg Caren M. , Smith Gary , Hemphill Robin R. , Bibler Zaidi Nikki L.
Published: September 2018

Problem

Multiple-choice question (MCQ) examinations represent a primary mode of assessment used by medical schools. It can be challenging for faculty to produce content-aligned, comprehensive, and psychometrically sound MCQs. Despite best efforts, sometimes there are unexpected issues with examinations. Assessment best practices lack a systematic way to address gaps when actual and expected outcomes do not align.

Approach

The authors propose using root cause analysis (RCA) to systematically review unexpected educational outcomes. Using a real-life example of a class’s unexpectedly low reproduction examination scores (University of Michigan Medical School, 2015), the authors describe their RCA process, which included a system flow diagram, a fishbone diagram, and an application of the 5 Whys to understand the contributors and reasons for the lower-than-expected performance. Using this RCA approach, the authors identified multiple contributing factors that potentially led to the low examination scores. These included lack of examination quality improvement (QI) for poorly constructed items, content–question and pedagogy–assessment misalignment, and other issues related to environment and people.

Outcomes

As a result of the RCA, the authors worked with stakeholders to address these issues and develop strategies to prevent similar systematic issues from reoccurring. For example, a more robust examination QI process was developed.

Next Steps

Using an RCA approach in health care is grounded in practice and can be easily adapted for assessment. Because this is a novel use of RCA, there are opportunities to expand beyond the authors’ initial approach for using RCA in assessment.
The Association Between a Holistic Review in Admissions Workshop and the Diversity of Accepted Applicants and Students Matriculating to Medical School
Authors: Grbic Douglas , Morrison Emory , Sondheimer Henry M. , Conrad Sarah S. , Milem Jeffrey F.
Published: September 2018

Purpose

The authors tested for an association between the Association of American Medical Colleges’ holistic review in admissions (HRA) workshop and the compositional diversity of medical school accepted applicants and matriculants in schools that held workshops compared with those that did not.

Method

The authors examined school-level data from 134 medical schools accredited by the Liaison Committee on Medical Education for the years 2006–2016 using information from the American Medical College Application Service. They used a fixed-effects regression to examine the within-school association between an HRA workshop and four measures of diversity: percent first-generation college student, percent black/African American, percent Hispanic, and overall level of racial/ethnic diversity as measured by a diversity index.

Results

For schools that held an HRA workshop, descriptive statistics showed higher mean values across all four measures of diversity for the post-HRA workshop period (the HRA implementation period) compared with the preworkshop period (accepted applicants: d = 0.34–0.79; matriculants: d = 0.29–0.73). Analyzing data for all schools, including those that did not hold a workshop, regression models showed that the HRA implementation period was associated with a significant and sustained increase in all four measures of diversity. These findings were consistent for both accepted applicants (P < .01) and matriculants (P < .01).

Conclusions

The significant increases in all four measures of diversity following an HRA workshop support the conclusion that this workshop was associated with increased compositional diversity at the participating medical schools.
Prescription Benzodiazepine Use Among Older Adults: A Critical Review
Authors: Gerlach Lauren B. , Wiechers Ilse R. , Maust Donovan T.
Published: September 2018

Objectives

Despite evidence for many potential risks, use of benzodiazepines (BZDs) among older adults is common. The authors evaluated the available evidence for BZD effectiveness and tolerability for use in older adults in three psychiatric conditions for which BZDs are commonly prescribed: insomnia, anxiety disorders, and behavioral and psychological symptoms of dementia.

Design

Electronic databases, including PubMed/MEDLINE, were searched to identify articles that (1) included patients ≥50 years of age, (2) focused on patients diagnosed with insomnia, anxiety disorders, or behavioral and psychological symptoms of dementia, and (3) were either a randomized, placebo-controlled trial or a randomized trial comparing a BZD with either another psychotropic medication or psychotherapy.

Results

Thirty-one studies met the inclusion criteria. Of the three clinical indications evaluated, treatment of insomnia had the greatest available evidence for use of BZDs among older adults, with 21 of 25 trials demonstrating improved sleep outcomes with use of BZDs. Only one trial was found to meet eligibility criteria for BZD use in anxiety disorders, demonstrating benefit over placebo. Five studies for use in behavioral disturbances in dementia were included, of which only one demonstrated improvement over placebo.

Conclusion

This systematic review suggests that BZD prescribing to older adults is significantly in excess of what the available evidence suggests is appropriate. Future trials should focus on efforts to reduce both acute and chronic BZD use among older adults while improving access to effective non-pharmacologic treatment alternatives.
A Survey of Perceived Implementation Gaps for a Clinical Practice Guideline for the Rehabilitation of Adults With Moderate to Severe Traumatic Brain Injury
Authors: Lamontagne Marie-Eve , Gargaro Judith , Marier-Deschênes Pascale , Truchon Catherine , Bayley Mark Theodore , Marshall Shawn , Kagan Corinne , Brière Anabèle , Swaine Bonnie
Published: September 2018

Objective:

Appraising current practice is an important prerequisite for implementation of clinical practice guidelines (CPGs). The study objective was to determine the perceived level of implementation, priority, and feasibility of a subset of key CPG recommendations for the rehabilitation of individuals with moderate to severe traumatic brain injury (MSTBI).

Methods:

Fifty-one teams at acute care and rehabilitation facilities were invited to complete an electronic survey addressing the perceived level of implementation, priority, and feasibility of 109 fundamental and priority recommendations from the CPG-MSTBI.

Results:

Forty-four clinical teams responded across 2 Canadian provinces. Most of the recommendations were deemed as “fully” or “mostly” implemented, while relative gaps in implementation were perceived in recommendations regarding coordination with mental health and addiction providers (>75% of respondents indicated low levels of implementation), “Caregivers and Families” (26%), and “Psychosocial and Adaptation Issues” (25%). Priority levels and perceived feasibility were generally high (>60% and >86%, respectively) for recommendations with low levels of implementation. Priority recommendations for implementation were identified for both acute care and rehabilitation settings in Québec and Ontario.

Conclusions:

Assessment of clinician perception provides a helpful perspective for implementation. Exploring perceived implementation gaps based on users' needs and expectation should be a part of an implementation process.
What Matters to Persons With Dementia at the End of Life
Authors: Kwak Jung , Noh Hyunjin
Published: September 2018

For substituted decision makers for the growing number of persons with dementia (PWDs), understanding the PWD's values is a prerequisite for making end-of-life (EOL) decisions congruent with the PWD's wishes. The current qualitative study explored PWD health care proxies' perspectives on values that are important to PWDs at end of life and challenges in making EOL decisions that reflect PWDs' values. Semistructured interviews were conducted with 20 PWD proxies, and data were analyzed using the content analysis, an inductive approach to identify themes. Three main themes emerged: (1) what matters to PWDs at end of life, (2) uncertainty about the PWD's current wishes and EOL trajectory poses challenges, and (3) the role of health care professionals' empathic and clear communication. Together, these findings suggest proxies' efforts to understand and respect PWDs' wishes at end of life and communication strategies that health care providers can use to help PWD proxies cope with uncertainty and challenges in EOL decision making.
Implementing a Resilience-Promoting Education Program for New Nursing Graduates
Authors: DuBois Carol Anderson , Zedreck Gonzalez Judith F.
Published: September 2018

Retaining qualified nurses at the bedside can have a positive impact on patient care safety and quality. Without support and resilience, nurses may become emotionally exhausted within the first year of practice. Nursing professional development educators must recognize that new nurses often struggle with stressors related to nursing and take the appropriate steps to help them build resilience. This article describes an education project implemented to assist new nurses in developing their resilience. It describes the process and outcomes of a resiliency training program infused into one healthcare facility’s nurse residency program and may inform nursing professional development educators planning similar programs.
Evaluating the Prognosis of Ischemic Stroke Using Low-Dose Multimodal Computed Tomography Parameters in Hyperacute Phase
Authors: Tang Biqiu , Zeng Jiaxin , Liu Lu , Xiao Yuan , Li Zhenlin , Zhang Kai , Chandan Shah , Zhao Youjin , Ye Zheng , Wang Wenhao , He Li , Lui Su
Published: September 2018

Purpose

The aim of this study was to evaluate the potential value of low-dose multimodal computed tomography (CT) in predicting prognosis of acute ischemic stroke (AIS) within 6 hours.

Methods

The admission “one-stop-shop” multimodal CT examination, including noncontrast CT (NCCT), low-dose CT perfusion, and CT angiography (CTA), was performed in patients with symptoms of stroke within 6 hours. Noncontrast CT, CTA source image (CTA-SI), cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), and mean transit time (MTT) maps were studied using Alberta Stroke Program Early CT Score (ASPECTS). The regional leptomeningeal collateral (rLMC) score (0–20) was dichotomized into 2 groups: good (11–20) and poor (0–10) rLMC. Poor functional outcomes were defined by a modified Rankin scale score of 3 to 6.

Results

One hundred forty-four patients were ultimately selected; 43.8% of them showed poor functional outcomes. They had lower ASPECTSs on NCCT, CTA-SI, CBV, CBF, TTP, and MTT, and poor rLMC was more frequently associated with poor functional outcomes (allP< 0.001). In the multivariate analysis for AIS patients with conservative treatment, CTA-SI-ASPECTS 6 or less (odds ratio [OR], 5.9; 95% confidence interval [95% CI], 1.9–18.4;P= 0.002) and poor collaterals (OR, 5.0; 95% CI, 1.3–15.4;P= 0.017), CBV-ASPECTS 6 or less (OR, 8.0; 95% CI, 2.7–24.0;P< 0.001), CBF-ASPECTS 4 or less (OR, 8.0; 95% CI, 2.0–31.5;P= 0.003), MTT-ASPECTS≤3 (OR, 5.8; 95% CI, 1.8–18.1;P= 0.003), TTP-ASPECTS 4 or less (OR, 5.0; 95% CI, 1.6–15.1;P= 0.005), and NCCT-ASPECTS 8 or less (OR, 5.9; 95% CI, 1.7–20.4;P= 0.005) were significantly associated with poor functional outcome. In the multivariate analysis for AIS patients with thrombolysis, CTA-SI-ASPECTS 6 or less (OR, 27.5; 95% CI, 2.9–262.3;P= 0.004), poor collaterals (OR, 28.0; 95% CI, 2.8–283.0;P< 0.028), and CBV-ASPECTS 6 or less (OR, 18.0; 95% CI, 3.0–107.7;P= 0.002) were associated with poor functional outcomes. Furthermore, the area under the curve (AUC) of the combination of CTA-SI-ASPECTS 6 or less, poor collaterals, and CBV-ASPECTS 6 or less (AUC, 0.87) was greater than that for any single parameter alone: CTA-SI-ASPECTS 6 or less (AUC, 0.80;P< 0.001), poor collaterals (AUC, 0.76;P< 0.001), and CBV-ASPECTS 6 or less (AUC, 0.81;P= 0.002).

Conclusions

The combination of CTA-SI-ASPECTS, collaterals, and CBV-ASPECTS may improve predictive power compared with a single parameter alone.
American College of Surgeons Committee on Trauma verification level affects trauma center management of pelvic ring injuries and patient mortality
Authors: Oliphant Bryant W. , Tignanelli Christopher J. , Napolitano Lena M. , Goulet James A. , Hemmila Mark R.
Published: September 2018

BACKGROUND

Pelvic ring fractures represent a complex injury that requires specific resources and clinical expertise for optimal trauma patient management. We examined the impact of treatment variability for this type of injury at Level I and II trauma centers on patient outcomes.

METHODS

Trauma quality collaborative data (2011–2017) were analyzed. This includes data from 29 American College of Surgeons Committee on Trauma verified Level I and Level II trauma centers. Inclusion criteria were adult patients (≥16 years), Injury Severity Score of 5 or higher, blunt injury, and evidence of a partially stable or unstable pelvic ring fracture injury coding as classified using Abbreviated Injury Scale version 2005, with 2008 updates. Patients directly admitted, transferred out for definitive care, with penetrating trauma, or with no signs of life were excluded. Propensity score matching was used to create 1:1 matched cohorts of patients treated at Levels I or II trauma centers. Trauma center verification level was the exposure variable used to compare management strategies, resource utilization, and in-hospital mortality in univariate analysis.

RESULTS

We selected 1,220 well-matched patients, from 1,768 total patients, using propensity score methods (610 Level I and 610 Level II cohort). There were no significant baseline characteristic differences noted between the groups. Patients with pelvic ring fractures treated at Level I trauma centers had significantly decreased mortality (7.7% vs. 11.6%, p = 0.02). Patients treated at Level II trauma centers were less likely to receive interventional angiography, undergo complicated definitive orthopedic operative treatment, and to be admitted to an intensive care unit.

CONCLUSION

Admission with a partially stable or unstable pelvic ring injury to a Level I trauma center is associated with decreased mortality. Level II trauma centers had significantly less utilization of advanced treatment modalities. This variation in clinical practice highlights potential processes to emphasize in the appropriate treatment of these critically ill patients.

LEVEL OF EVIDENCE

Economic/Decision, Level II.
Clearing the cervical spine in patients with distracting injuries: An AAST multi-institutional trial
Authors: Khan Abid D. , Liebscher Sean C. , Reiser Hannah C. , Schroeppel Thomas J. , Anstadt Michael J. , Bosarge Patrick L. , Carroll Shannon L. , Quick Jacob A. , Barnes Stephen L. , Sobrino Justin , Murry Jason , Morin Nicholas , Gomez Mario , Consani Heitor , Gonzalez Richard P.
Published: September 2018

BACKGROUND

Single institution studies have shown that clinical examination of the cervical spine (c-spine) is sensitive for clearance of the c-spine in blunt trauma patients with distracting injuries. Despite an unclear definition, most trauma centers still adhere to the notion that distracting injuries adversely affect the sensitivity of c-spine clinical examination. A prospective AAST multi-institutional trial was performed to assess the sensitivity of clinical examination screening of the c-spine in awake and alert blunt trauma patients with distracting injuries.

METHODS

During the 42-month study period, blunt trauma patients 18 years and older were prospectively evaluated with a standard c-spine examination protocol at 8 Level 1 trauma centers. Clinical examination was performed regardless of the presence of distracting injuries. Patients without complaints of neck pain, tenderness or pain on range of motion were considered to have a negative c-spine clinical examination. All patients with positive or negative c-spine clinical examination underwent computed tomography (CT) scan of the entire c-spine. Clinical examination findings were documented prior to the CT scan.

RESULTS

During the study period, 2929 patients were entered. At least one distracting injury was diagnosed in 70% of the patients. A c-spine injury was found on CT scan in 7.6% of the patients. There was no difference in the rate of missed injury when comparing patients with a distracting injury to those without a distracting injury (10.4% vs. 12.6%, p = 0.601). Only one injury missed by clinical examination underwent surgical intervention and none had a neurological complication.

CONCLUSIONS

Negative clinical examination may be sufficient to clear the cervical spine in awake and alert blunt trauma patients, even in the presence of a distracting injury. These findings suggest a potential source for improvement in resource utilization.

LEVEL OF EVIDENCE

Therapeutic/care management, level IV.
Contributions of lunate cells and wax crystals to the surface anisotropy ofNepenthesslippery zone
Authors: Wang Lixin , Tao Dashuai , Dong Shiyun , Li Shanshan , Tian Yu
Published: September 2018

Nepenthesslippery zone presents surface anisotropy depending on its specialized structures. Herein, via macro–micro–nano scaled experiments, we analysed the contributions of lunate cells and wax crystals to this anisotropy. Macroscopic climbing of insects showed large displacements (triple body length within 3 s) and high velocities (6.16–20.47 mm s−1) in the inverted-fixed (towards digestive zone) slippery zone, but failed to climb forward in the normal-fixed (towards peristome) one. Friction force of insect claws sliding across inverted-fixed lunate cells was about 2.4 times of that sliding across the normal-fixed ones, whereas showed unobvious differences (1.06–1.11 times) between the inverted- and normal-fixed wax crystals. Innovative results from atomic force microscope scanning and microstructure examination demonstrated the upper layer of wax crystals causes the cantilever tip to generate rather small differences in friction data (1.92–2.72%), and the beneath layer provides slightly higher differences (4.96–7.91%). The study confirms the anisotropic configuration of lunate cells produces most of the anisotropy, whereas both surface topography and structural features of the wax crystals generate a slight contribution. These results are helpful for understanding the surface anisotropy ofNepenthesslippery zone, and guide the design of bioinspired surface with anisotropic properties.