bluuebunny/crossref_metadata_2025_split huggingface dataset:
An anatomical investigation of the proximal vertebral arteries (V1, V2) in a select South African population
Authors: Omotoso B. R. , Harrichandparsad R. , Moodley I. G. , Satyapal K. S. , Lazarus L. 
Published: March 2021

Abstract
Introduction
The most common type of vascular complication during cervical spine surgery is the vertebral artery (VA) injury. The presence of anatomical variation in the artery's morphology has been a significant factor for arterial injury during surgery. Therefore, physicians planning interventions in the craniospinal region need to be aware of the extents of variations. In addition to vascular injury, anatomical variations can predispose to some pathologies in the posterior circulation territory. To provide useful data to interventional radiologists, anatomists, and surgeons, we evaluated the anatomical features of the V1 and V2 segments of the VA in a South African population.

Materials and methods
The study is an observational, retrospective chart review of 554 consecutive South African patients (Black, Indian and White) who had undergone computed tomography angiography (CTA) from January 2009 to September 2019.

Results
The VA exhibited morphological variation in its course. We report the incidence of variant origin of the left VA, all from the aortic arch. Variation in the level of entry into the transverse foramen ranged between C7 and C3. A left dominant pattern was observed; we also report on hypoplasia of the VA. In addition, we report incidence of VA tortuosity at V1, V2 to be 76.6% and 32.1%, respectively.

Conclusions
The baseline data established in this study regarding the diameter, variant origin, and level of entry into the transverse foramen will assist neurosurgeons and interventional radiologists in interpreting, diagnosing, and planning and executing various vascular procedures and treatment of pathology in the vicinity of the VA.
Deep learning–based reconstruction may improve non-contrast cerebral CT imaging compared to other current reconstruction algorithms
Authors: Oostveen Luuk J. , Meijer Frederick J. A. , de Lange Frank , Smit Ewoud J. , Pegge Sjoert A. , Steens Stefan C. A. , van Amerongen Martin J. , Prokop Mathias , Sechopoulos Ioannis 
Published: March 2021

Abstract
Objectives
To evaluate image quality and reconstruction times of a commercial deep learning reconstruction algorithm (DLR) compared to hybrid-iterative reconstruction (Hybrid-IR) and model-based iterative reconstruction (MBIR) algorithms for cerebral non-contrast CT (NCCT).

Methods
Cerebral NCCT acquisitions of 50 consecutive patients were reconstructed using DLR, Hybrid-IR and MBIR with a clinical CT system. Image quality, in terms of six subjective characteristics (noise, sharpness, grey-white matter differentiation, artefacts, natural appearance and overall image quality), was scored by five observers. As objective metrics of image quality, the noise magnitude and signal-difference-to-noise ratio (SDNR) of the grey and white matter were calculated. Mean values for the image quality characteristics scored by the observers were estimated using a general linear model to account for multiple readers. The estimated means for the reconstruction methods were pairwise compared. Calculated measures were compared using paired t tests.

Results
For all image quality characteristics, DLR images were scored significantly higher than MBIR images. Compared to Hybrid-IR, perceived noise and grey-white matter differentiation were better with DLR, while no difference was detected for other image quality characteristics. Noise magnitude was lower for DLR compared to Hybrid-IR and MBIR (5.6, 6.4 and 6.2, respectively) and SDNR higher (2.4, 1.9 and 2.0, respectively). Reconstruction times were 27 s, 44 s and 176 s for Hybrid-IR, DLR and MBIR respectively.

Conclusions
With a slight increase in reconstruction time, DLR results in lower noise and improved tissue differentiation compared to Hybrid-IR. Image quality of MBIR is significantly lower compared to DLR with much longer reconstruction times.

Key Points
• Deep learning reconstruction of cerebral non-contrast CT results in lower noise and improved tissue differentiation compared to hybrid-iterative reconstruction.
• Deep learning reconstruction of cerebral non-contrast CT results in better image quality in all aspects evaluated compared to model-based iterative reconstruction.
• Deep learning reconstruction only needs a slight increase in reconstruction time compared to hybrid-iterative reconstruction, while model-based iterative reconstruction requires considerably longer processing time.
Bygones in a public project
Authors: Haita-Falah Corina 
Published: March 2021

AbstractThe experimental literature suggests that contributions to a public good made dynamically, over multiple stages are higher than contributions made in a static setting, even when players do not receive feedback about co-players’ previous contributions between stages. Because the dynamic setting without feedback is strategically equivalent to the static one, this finding is puzzling. One important difference between the two settings, however, is that the dynamic setting gives the opportunity to sink contributions while in the static one this opportunity does not exist. I test whether the sunk character of the dynamic contributions explains the higher contributions in the dynamic setting. Symmetric players contribute in two stages to a threshold public good and receive feedback after each stage. The experimental treatment differ in whether the first-stage contributions are sunk or not when deciding on the second-stage contributions. The results show that making the first-stage contributions sunk increases the second-stage individual contributions, and this is more so the case at higher levels of the first-stage contributions. This suggests that the sunk contributions do, at least partially, explain the better performance of the dynamic setting.
Diagnostic limitation of laryngostroboscopy in comparison to laryngeal electromyography in synkinesis in unilateral vocal fold paralysis
Authors: Stanisz Isabella , Leonhard Matthias , Denk-Linnert Doris-Maria , Schneider-Stickler Berit 
Published: March 2021

Abstract
Purpose
In clinical practice, laryngo(strobo)scopy (LS) is still mainly used for diagnostics and management of unilateral vocal fold paralysis (UFVP), although only laryngeal electromyography (LEMG) can provide information on causes of vocal fold immobility, especially on possible synkinetic reinnervation after recurrent laryngeal nerve (RLN) injury. The goal of this retrospective study was the evaluation whether signs of synkinetic reinnervation in LS can be objectified in comparison to LEMG data.

Methods
Between 1/2015 and 2/2018, 50 patients with laryngostroboscopically suspected UVFP received routine LEMG examination. The LEMG findings were retrospectively compared with LS findings. The LEMG data analysis focused on the diagnosis of synkinetic reinnervation of the TA/LCA and/or PCA. The digital LS recordings were retrospectively re-evaluated by phoniatricians considering 22 selected laryngostroboscopic parameters.

Results
LEMG revealed synkinesis in 23 (46%) and absence of synkinesis in 27 (54%) patients. None of the 22 parameters showed significant association between patients with synkinetic reinnervation and LS findings. The only laryngostroboscopic parameter that was significantly associated with a silent LEMG signal compared to single fiber activity in LEMG was a length difference on the side of the UVFP (p-value 0.0001; OR 14.5 (95% CI 3.047–66.81; Sensitivity 0.5; Specificity 0.9355).

Conclusion
Our findings show that synkinesis cannot be diagnosed using only LS. This study underlines the importance of LEMG in clinical routine for detection of laryngeal synkinesis in patients with UVFP before any further therapeutic steps are initiated to avoid later therapy failure.
Management of tympanic membrane retractions: a systematic review
Authors: Bayoumy Ahmed B. , Veugen Christianne C. A. F. M. , van der Veen Erwin L. , Bok Jan-Willem M. , de Ru Jacob A. , Thomeer Hans G. X. M. 
Published: March 2021

Abstract
Importance
Tympanic membrane retraction (TMR) is a relatively common otological finding. However, no consensus on its management exists. We are looking especially for a treatment strategy in the military population who are unable to attend frequent follow-up visits, and who experience relatively more barotrauma at great heights and depths and easily suffer from otitis externa from less hygienic circumstances.

Objective
To assess and summarize the available evidence for the effectiveness of surgical interventions and watchful waiting policy in patients with a tympanic membrane retraction.

Evidence review
The protocol for this systematic review was published at Prospero (207859). PubMed, Embase, and the Cochrane Database of Systematic Reviews were systematically searched from inception up to September 2020 for published and unpublished studies. We included randomized trials and observational studies that investigated surgical interventions (tympanoplasty, ventilation tube insertion) and wait-and-see policy. The primary outcomes of this study were clinical remission of the tympanic membrane retraction, tympanic membrane perforations and cholesteatoma development.

Findings
In total, 27 studies were included, consisting of 1566 patients with TMRs. We included data from 2 randomized controlled trials (76 patients) and 25 observational studies (1490 patients). Seven studies (329 patients) investigated excision of the TMR with and without ventilation tube placement, 3 studies (207 patients) investigated the wait-and-see policy and 17 studies (1030 patients) investigated tympanoplasty for the treatment of TMRs.

Conclusions and relevance
This study provides all the studies that have been published on the surgical management and wait-and-policy for tympanic membrane retractions. No high level of evidence comparative studies has been performed. The evidence for the management of tympanic membrane retractions is heterogenous and depends on many factors such as the patient population, location and severity of the TMR and presence of other ear pathologies (e.g., perforation, risk of cholesteatoma and serous otitis media).
Towards an holistic account on residual stresses in full-forward extruded rods
Authors: Floros Dimosthenis , Jobst Andreas , Kergaßner Andreas , Merklein Marion , Steinmann Paul 
Published: March 2021

AbstractAn holistic view is attempted towards prediction of the effect of residual stresses induced by full-forward extrusion on fatigue life of workpieces during operation. To study the effect of constitutive model on the accuracy of forming simulations, a combined nonlinear isotropic/kinematic hardening model as well as the isotropic hardening part of the same model are calibrated based on five compression-tension-compression uniaxial stress experiments. A full-forward extrusion finite element model is developed adapting both the aforementioned hardening plasticity models and the predicted residual stress states at the surface of the workpiece are compared against that of a corresponding forming experiment. Results show residual stress predictions of remarkable accuracy by the FE-models with the isotropic hardening model. The effect of residual stresses on fatigue life of the workpiece is qualitatively studied by uncoupled multiscale simulations featuring gradient crystal plasticity at the microscale. While the effective (homogenized) macroscale response indicates elastic response during a macroscopically cyclic loading, plasticity accompanying reduction of residual stresses is still present at the microscale within, e.g. grain boundaries.
Evaluating tree-to-tree competition during stand development in a relict Scots pine forest: how much does climate matter?
Authors: Marqués Laura , Camarero J. Julio , Zavala Miguel A. , Stoffel Markus , Ballesteros-Cánovas Juan A. , Sancho-García Cesar , Madrigal-González Jaime 
Published: March 2021

AbstractKey messageCompetitive interactions change over time and their influence on tree growth is intensified during drought events in marginal Scots pine populations.AbstractCompetition is a key factor driving forest dynamics and stand structure during the course of stand development. Although the role of neighbourhood competition on stand dynamics has received increasing attention, the response of competition to environmental fluctuations and stand development remains poorly explored. We evaluated changes in competition during stand development in a dry-edge Scots pine relict population located in Central Spain. Typically, tree-to-tree interactions have been investigated through static competition measurements, which usually lack the temporal variation associated to natural forest development and environmental conditions. Here, we assessed how individual and neighbourhood components of competition evolved along a 35-year period, and we related competition dynamics to population structure and drought levels. On six plots, 508 trees were mapped and diameters at breast height (DBH) were measured. Two increment cores were taken from target trees to derive basal area increment (BAI), and neighbourhood was reconstructed back to 1980. Results provide insights into inter-annual variability in competition effects and their role on tree radial growth depending on climatic conditions. From the year 2005 onwards, both individual and neighbourhood components of competition showed a decoupled pattern over time. This effect was particularly pronounced during the extreme drought in 2012, in which the individual component decreased, whereas the neighbourhood component increased. In addition, climatic variability modulated the competition effects during stand development. This approach of evaluating competition dynamics proves to be promising for studying forest stand development and the influence of climate impacts on tree populations subjected to xeric conditions.
Maps, trends, and temperature sensitivities—phenological information from and for decreasing numbers of volunteer observers
Authors: Yuan Ye , Härer Stefan , Ottenheym Tobias , Misra Gourav , Lüpke Alissa , Estrella Nicole , Menzel Annette 
Published: March 2021

AbstractPhenology serves as a major indicator of ongoing climate change. Long-term phenological observations are critically important for tracking and communicating these changes. The phenological observation network across Germany is operated by the National Meteorological Service with a major contribution from volunteering activities. However, the number of observers has strongly decreased for the last decades, possibly resulting in increasing uncertainties when extracting reliable phenological information from map interpolation. We studied uncertainties in interpolated maps from decreasing phenological records, by comparing long-term trends based on grid-based interpolated and station-wise observed time series, as well as their correlations with temperature. Interpolated maps in spring were characterized by the largest spatial variabilities across Bavaria, Germany, with respective lowest interpolated uncertainties. Long-term phenological trends for both interpolations and observations exhibited mean advances of −0.2 to −0.3 days year−1 for spring and summer, while late autumn and winter showed a delay of around 0.1 days year−1. Throughout the year, temperature sensitivities were consistently stronger for interpolated time series than observations. Such a better representation of regional phenology by interpolation was equally supported by satellite-derived phenological indices. Nevertheless, simulation of observer numbers indicated that a decline to less than 40% leads to a strong decrease in interpolation accuracy. To better understand the risk of declining phenological observations and to motivate volunteer observers, a Shiny app is proposed to visualize spatial and temporal phenological patterns across Bavaria and their links to climate change–induced temperature changes.
Impact of chest subcutaneous fat on the occurrence of central venous port-related infectious complications in cancer patients
Authors: Shibata Jumpei , Kawamura Hidetaka , Hiramatsu Kazuhiro , Honda Michitaka , Shibata Yoshihisa , Aoba Taro , Fujii Masahiro , Arimoto Atsuki , Ito Akira , Ishii Kenta , Omiya Kojiro , Asai Mariko , Arakawa Takuya , Gonda Hirotake , Asai Shuhei , Hasegawa Takuya , Kawashima Kento , Kato Takehito 
Published: March 2021

Abstract
Purpose
There is no concrete evidence to support the association between the amount of subcutaneous fat area (SFA) in the central venous port-insertion site (precordium) and port-related complications. We aimed to investigate the relationship between SFA in the midclavicular line and postoperative infectious complications in patients undergoing port-insertion surgery.

Methods
This was a single-institute and historical cohort study of 174 patients who underwent first central venous port implantation surgery for chemotherapy between January 2014 and December 2018. SFA in the midclavicular line was measured using preoperative computed tomography scans. The patients were divided into three groups according to SFA amount tertiles, and we investigated the association of SFA with infectious and all-cause complication events within 1 year.

Results
Within a median follow-up of 306 days, the patients with intermediate SFA had significantly higher infection-free survival than those with low and high SFA (low vs. intermediate vs. high: 80.4% vs. 97.7% vs. 83.4%, respectively, p=0.034). In contrast, there was no significant difference in the overall complication-free survival among the groups (low vs. intermediate vs. high: 80.4% vs. 88.9% vs. 81.8%, respectively, p=0.29). Low SFA was independently associated with high risk of infectious complications (hazard ratio, 9.45; 95% confidence interval, 1.07–83.22, p=0.043).

Conclusion
Low SFA in the midclavicular line was an independent risk factor for infectious complications in the chemotherapy setting. This practical indicator can be useful for optimizing patients’ nutritional status and when considering other types of vascular access to support administration of intravenous chemotherapy.
Correlation between different instrumentation variants and the degree of destabilization in treating cervical spondylotic spinal canal stenosis by unilateral hemilaminectomy with bilateral decompression: a biomechanical investigation
Authors: Fiss Ingo , Mielke Dorothee , Rohde Veit , Psychogios Marios , Schilling Christoph 
Published: March 2021

Abstract
Purpose
Unilateral hemilaminectomy with bilateral decompression (BDZ) was proposed as an alternative decompressive procedure in cervical spondylotic myelopathy (CSM). Despite promising clinical results, the destabilizing effect is yet unknown. We therefore performed a biomechanical study to investigate whether lateral mass screw fixation should follow BDZ.

Methods
Six human C2–C7 cervical specimens were tested under various conditions: native, unilateral hemilaminectomy with bilateral decompression without/with fixation (BDZ/BDF), unilateral hemilaminectomy with bilateral decompression and unilateral foraminotomy without/with fixation (UFZ/UFF), unilateral hemilaminectomy with bilateral decompression and bilateral foraminotomy without/with fixation (BFZ/BFF), and laminectomy without/with fixation (LAZ/LAF). Instrumention was applied from C3–C6. For each condition, the three-dimensional kinematics of the cervical specimen were measured in three main loading directions with an ultrasonic motion analysis system. ANOVA was used to determine differences between the specific segment conditions to assess the parameter’s range of motion (ROM) and neutral zone (NZ).

Results
For flexion–extension, lateral bending and axial rotation, ROM of BDZ, UFZ, BFZ and LAZ remained at the level of the native condition (p > 0.74), whereas fixation reduced ROM significantly (p < 0.01). Between BDF, UFF, BFF and LAF, no significant differences in reduction in ROM were seen (p > 0.49). Results for NZ were equivalent to ROM in flexion–extension and lateral bending. For axial rotation, NZ remained almost constant on the native level for all tested conditions.

Conclusion
Bilateral decompression via a hemilaminectomy, even if combined with foraminotomy, could be a less invasive treatment option for multilevel CSM in patients with lordotic cervical alignment and absence of segmental instability.
Reconstruction of operating loads in wind turbines with inertial measurement units
Authors: Wiens Marcus , Martin Tim , Meyer Tobias , Zuga Adam 
Published: March 2021

AbstractWind turbines are a major source of renewable energy. Load monitoring is considered to improve reliability of the systems and to reduce the cost of operation. We propose a load monitoring system which consists of inertial measurement units. These track the movement of rotor blade, hub and tower top. In addition, wind turbine states, e.g. yaw angle, pitch angle and rotation speed, are recorded. By solving a navigation algorithm with a Kalman Filter approach, the raw sensor data is combined with an error model to reduce the tracking error. In total, five inertial measurement units are installed on the research wind energy converter AD 8–180 on the test site in Bremerhaven. Results show that tracking the blade movement in full operation is possible and that loads can be estimated with a model-based approach. In comparison to simulations, the blade deflections can be approximated by an aeroelastic model. The presented approach can be used as basis for comprehensive load monitoring and observer system with additional increase of system robustness by measurement redundancy.
The role of coalitions at international tariff negotiations: a CGE perspective
Authors: Freund Florian 
Published: March 2021

AbstractDeveloping countries coalitions form an integral part of tariff negotiations that take place under the aegis of the World Trade Organization. While there was only a single coalition in the 70s, their number increased to 31 in the year 2005. Despite the apparent proliferation of coalitions in tariff negotiations, little research on their theoretical and empirical implications has been produced. In particular, we lack an understanding of efficiency and equity effects of coalitions. By exploring this equity-efficiency nexus, the study finds that developing countries coalitions like the G-90 and the Least Developed Countries Group – while benefiting member countries – lead to less efficiency and less equity overall. Forming the Cairns Group, however, leads to a more efficient and equal distribution of the gains from trade.