bluuebunny/crossref_metadata_2025 huggingface dataset:
New approach to modelling protection in grid planning studies
Authors: McGuinness Sean , Patel Mahendra
Published: July 2018

In many recent blackouts and large system disturbances, the performance of protection systems was found to have played an important role in both exacerbating the disturbance and limiting the spread of the disturbance. In the past, protection systems were not widely modelled in transmission planning studies. Instead, the response of protection relays to faults was assumed to follow fixed behaviour based on conservative values for primary and backup protection operating times. For these reasons, the incorporation of more accurate representations of protection systems into planning studies may help identify potential protection misoperations and ensure that protection relay performance is tuned to yield optimum responses to system disturbances. This study begins by discussing how protection relays may participate and respond to cascading tripping, power swings, and other steady‐state and transient power system phenomena studied in power system planning. It will then examine how the settings for relays may be populated with conservative ranges where actual settings are not known or difficult to transfer to the planning simulation tool. The paper concludes with an overview of a tool which has been developed to automatically create relay models in planning simulation based on high‐level user guidance.
Performance evaluation of the travelling wave‐based differential protection when applied on Hybrid Transmission Lines
Authors: Lopes Felipe V. , Ribeiro Caio M.S. , Ribeiro João Paulo G. , Leite Eduardo Jorge S.
Published: July 2018

This study evaluates the travelling wave‐based differential protection (TW87) when applied on hybrid transmission lines (HTLs). The TW87 has attracted the interest of utilities due to its high‐speed operation and reliability. However, to apply such a function on lines that combine overhead and underground cable sections, additional challenges arise, which must be overcome to guarantee the proper TW87 operation. The goal of this study is to clarify issues related to the TW87 settings and performance when applied on HTLs, highlighting the impact of the used settings on the protection operation. To do so, fault scenarios on a 230 kV/60 Hz test power system were simulated using the alternative transients programme. The obtained results attest the TW87 is able to properly protect HTLs, provided that special requirements are considered.
Tinkering with the power balance of a transformer
Authors: Steinhauser Fred
Published: July 2018

Explicit current transformers (CTs) are used to measure the currents at power transformers, but these efforts are often saved for the voltage measurements. However, even if there are no dedicated voltage transformers (VTs) attached at the power transformer itself, the voltages at the buses will be measured somewhere. By using Sampled Values, the voltage measurements can be easily delivered to any protection function that requires them. The time synchronised measurements can be simply aligned and processed by the protection algorithms. Transformer differential protection works with Sampled Values just as well as with classical secondary currents. However, with the availability of both the voltages and currents at the transformer, some experiments can be made. Not only Kirchhoff's law for the currents applies, but also the conservation of energy, so the power flow through the transformer must also be balanced. With all the measurements available, the power balance from all terminals is easily observed, vector groups need not be taken into account. In a simulation, the power system quantities are produced as Sampled Values and recorded. Power measurements during the course of power systems faults are compared and the feasibility of such a concept is discussed.
Test of a fast adaptive reclosing algorithm for transmission lines using a programmable hardware
Authors: Dias Ozenir , Magrin Fabiano , Tavares Maria Cristina
Published: July 2018

This study presents the application of single‐phase and three‐phase adaptive reclosing method for transmission lines using a commercial protection relay. The method ensures the application of the automatic reclosing just after the extinction of a transient fault, the blocking of the automatic switching and, subsequently, the three‐phase tripping for permanent faults. The study describes the proposed method implementation in a commercial relay. To represent both transient and permanent faults, oscillograms of real cases were used. The contributions of this work are the method to test the new algorithm in a commercial hardware, the distinction between transient and permanent faults and the detection of transient fault extinction through adaptive algorithms using commercial equipment.
Investigating the impact of network security on the line current differential protection system
Authors: Aichhorn Andreas , Unterweger Andreas , Mayrhofer René , Engel Dominik
Published: July 2018

This paper analyses the influence of network security measures on the system behaviour of a power system protection device. In this particular case, an IP‐based Ethernet protection interface of a line current differential protection system is considered. IPsec has previously been proposed to be part of the security concept of the protection interface. Therefore, the authors conduct a trade‐off analysis regarding the influence of IPsec on the protection function and consequently on the system safety. This work shows that the protection function of the relay is not impaired as long as the additional CPU performance for the encryption by the protection relay is available and the necessary bandwidth on the communication channel is provided.
Generator grouping cutset determination based on tree construction and constrained spectral clustering
Authors: Tyuryukanov Ilya , Karagiannis Kaltsikis Alexandros C. , Popov Marjan , van der Meijden Mart A.M.M. , Terzija Vladimir
Published: July 2018

With the advent of wide area monitoring protection and control, the new wide area control and protection applications emerge that require the identification of zones or islands in the network subject to certain specific requirements. The requirement of retaining certain buses in the same network zone or island appears in several power system protection applications, including intentional controlled islanding and parallel power system restoration. This study describes a new algorithm to define islands in power networks with respect to the specified bus grouping constraints. The method is based on the construction of tree subgraphs spanning the buses of each group, and its superior performance is demonstrated by a comparison with the two state‐of‐the‐art methods from the literature.
Grid topology and technology influences on selective protection concepts for multi‐terminal medium voltage DC grids
Authors: Stumpe Maximilian , Tunnerhoff Philipp , Schnettler Armin , Schmidt Daniel
Published: July 2018

The integration of distributed renewable energy resources in combination with advancements in power electronics make the application of multi‐terminal medium voltage DC grids a promising and flexible solution. Fast and selective protection concepts in combination with DC (disconnecting) switches for fault handling are required to ensure high reliability and safe grid operation of these systems. Medium voltage DC grids may be realised based on several converter technologies with different fault clearing capability. Depending on the converter technology, switches for isolating faulted branches or DC circuit breakers (CBs) for fault clearance become necessary. DC medium voltage CB concepts have already been proposed. However, the switching times of these CBs vary significantly depending on the presence or absence of mechanical components resulting in different requirements for fault detection. This contribution evaluates the relations between different converter and DC CB technologies, DC grid topologies and fault detection methods according to selective fault clearing. Transient simulation studies are carried out for the development of protection concepts. Based on the results, reasonable technological combinations of the above‐mentioned technologies are identified. Special consideration is given to the dimensioning of series reactors as fault current rise limiting devices.
Metrology requirements of state‐of‐the‐art protection schemes for DC microgrids
Authors: Li Chunpeng , Rakhra Puran , Norman Patrick , Burt Graeme , Clarkson Paul
Published: July 2018

Environmental incentives to combat climate change are providing the motivation to improve the energy efficiency of power distribution systems and integrate state‐of‐the‐art renewable technologies. Examples include wind/photovoltaic resources, energy storage systems, and electric vehicles integrated via efficient power electronic converters (PEC). Subsequently, DC microgrids (MGs) and distribution systems are receiving considerable attention in the literature because they offer a simple, yet flexible, interface between these modern resources and consumers. However, many technical challenges relating to the design and standardisation of DC protection devices still exist that must be overcome prior to widespread adoption. For example, many protection schemes tailored for DC MGs have been proposed, but few of them have considered the metrology requirements for practical implementation. This study will first review the key features of DC‐side fault transients simulated on a DC MG model in MATLAB/Simulink, and analyse the disruptive impact on PEC components. Secondly, a review of newly published DC protection schemes is performed. These protection schemes are classified by their fundamental operating principles and mathematically derived metrology requirements are given.
Design of DC‐line terminating inductors for enhancement of protective functions in MTDC grids
Authors: Tzelepis Dimitrios , Dysko Adam , Booth Campbell , Mirsaeidi Sohrab , Dong Xinzhgou
Published: July 2018

This study presents a detailed DC‐side fault analysis considering inductive termination of lines within a high‐voltage multi‐terminal direct current (MTDC) grid. The analysis aims to provide design guidelines for DC‐side inductors, taking into account important aspects of protection such as the required speed of operation of relays and the performance characteristics of current interruption devices (i.e. of DC circuit breakers). Moreover, the impact of current limiting inductors on the fault signatures is investigated. In particular, it has been found that DC‐side inductors not only limit the fault current level, but also the resulting signatures in voltage and current, can assist to enhance the speed of operation, stability and selectivity of protective functions for DC‐side faults. The analysis has been extended to include the impact of inductive termination on fast transient phenomena known as travelling waves. Specifically, DC‐side inductors can form a significant reflection boundary for the generated travelling waves. A deeper insight into the faults has been achieved by utilising wavelet transform.
RTDS‐based HIL testing platform for complex modern electricity transmission systems
Authors: Xue Ying , Kong Dechao , Guan Rui , Li Jianing , Taylor Andrew , Zhang Xiao‐Ping
Published: July 2018

This study demonstrates the capability and performance of the developed state‐of‐the‐art hardware‐in‐the‐loop (HIL) testing platform based on the real‐time digital simulator (RTDS). The evaluations of (i) the effects of thyristor‐controlled series compensation (TCSC) on the feeder protection first main (unit protection) and (ii) the performance of feeder protection second main (distance protection) of multi‐ended transmission circuits with adjacent TCSC are carried out. Realistic parameters of transmission lines and TCSC are used for system modelling, and practical physical relays are used for the testing. The potential impacts of TCSC on both unit protection and distance protection are analysed based on the simulation results and relay measurements from the developed RTDS‐based HIL testing platform.
Time-dependent spectral-feature variations of stars displaying the B[e] phenomenon
Authors: Polster J. , Korčáková D. , Manset N.
Published: July 2018

We present an alternative model of V2028 Cyg, a B[e] star of FS CMa type. The star V2028 Cyg is atypical among FS CMa stars due to its composite spectra of B4III and K2II-Ib type. Our modelling of the temporal variability of the Hα line bisectors indicates as the most probable model a geometrically and optically thick disc, which is surrounded by a dusty ring seen almost edge-on. This provides a possibility that the K-spectral component is formed in the disc.
Electrical characterization of argon and nitrogen based cold plasma jet
Authors: Deepak G. Divya , Joshi Narendra Kumar , Prakash Ram , Pal Udit
Published: July 2018

In this paper, a dielectric barrier discharge plasma based atmospheric pressure plasma jet has been generated in a floating helix and floating end ring electrode configuration using mixture of argon and nitrogen gases (50:50 ratio). This configuration is subjected to a range of supply frequencies (10–25 kHz) and supply voltages (6.5–9.5 kV) at a fixed rate of gas flow rate (i.e., 1 l/min). The electrical characterization of the plasma jet has been carried out using a high voltage probe and current transformer. The current–voltage characteristics have been analyzed, and the power consumed by the device has been estimated at different applied combinations of supply frequency and voltages for optimum power consumption and maximum jet length. A comparative analysis of the results of the above experiments has shown that maximum power consumed by the device in helix electrode configuration with end ring is 19 W for (Ar+N2) mixture as compared to only 12 mW and 7.7 mW for Ar and He gas respectively (With end ring), this may be due to the main ionization mechanisms which are different depending on the working gas. Furthermore, maximum jet length of 42 mm has been obtained for He gas at 6 kV/25 kHz due to penning ionization process in comparison to jet lengths of only 32 mm for Ar gas and jet length of only 26 mm for Ar+N2mixture. The obtained average power consumed and maximum jet length for mixture of (Ar+N2) gases are 6.5 W and 26 mm.
Wie komplex muss unsere Therapie sein? – Lähmt uns zu viel Wissen?
Authors: Kraus Dennis
Published: July 2018

Aktiv zuhören, screenen, erste Hypothese, Probebehandlung, Wiederbefund. Gehen Sie so vor? Oder erschlägt Sie die Komplexität Ihres Wissens und des vielerorts formulierten Anspruchs nach evidenzbasierter Therapie? Im Durchschnitt kommen die Patienten mit einem Sechser-Rezept in die Praxis. Beispielsweise mit Problemen im Bereich des SIG. Ich kenne etwa 15 Tests – nicht alle erfüllen die Gütekriterien. Wo fange ich an, wo höre ich auf? Kommt Ihnen das bekannt vor?
Analyse und Therapie des schmerzhaften Patellofemoralgelenks
Authors: Rogan Slavko , Taeymans Jan , Clijsen Ron , Hähni Michaela
Published: July 2018

Um ein schmerzhaftes Patellofemoralgelenk (s-PFG) adäquat zu untersuchen, ist es essenziell, die biomechanischen Gegebenheiten der gesamten unteren Extremität zu
analysieren. In die Analyse fließen außerdem knöcherne, muskuläre und ligamentäre Komponenten ein, um so die effektivste Therapie für den Patienten
auszuwählen.
Tests und Assessments für die Rehabilitation nach VKB-Rekonstruktion
Authors: Boger Axel , Brem Peter
Published: July 2018

Das primäre Ziel der Rehabilitation nach einer Rekonstruktion des vorderen Kreuzbands ist die Rückkehr zur Aktivität bzw. zum Sport. Daher scheint es umso
wichtiger, eine Testbatterie nutzen zu können, die verlässliche Werte für die Wiederaufnahme von Training bzw. Sport generiert. Dafür sind standardisierte Tests
und Assessments auf der Aktivitäts- und Partizipationsebene am aussagekräftigsten, bei denen die Durchführung, die Auswertung und die Interpretation vorgegeben
sind.
Stereoselective Synthesis of 4-Substituted 2,4-Dichloro-2-butenals by α- and γ-Regioselective Double Chlorination of Dienamine Catalysis
Authors: Arimitsu Satoru , Terukina Kazuto , Ishikawa Tatsuro
Published: July 2018

The l-proline-catalyzed reaction of enolizable α,β-unsaturated aldehydes with N-chlorosuccinimide (NCS) gave the corresponding 4-substituted 2,4-dichloro-2-butenals with moderate yields and excellent diastereoselectivities (Z/E = >20/1) through consecutive double chlorination at the α- and γ-positions of the dienamine intermediate. The corresponding 2,4-dichloro-2-butenals contain a multireactive 1,3-dichloro allylic unit useful for the construction of Z-vinyl chlorides; the chloride on the allylic position was replaced with mild nucleophiles such as MeOH and EtOH via an SN2 substitution reaction, and its aldehyde moiety was used as a synthetic handle and transformed into an alcohol or a vinyl group. All products obtained after those synthetic manipulations maintained excellent diastereoselectivities (Z/E = >20/1).
Improved One-Pot, Four-Component Strategy to Access ­Functionalized Dihydropyridines by Using 4-(N,N-Dimethylamino)pyridine as a Catalyst
Authors: Lalitha Appaswami , Ramesh Rathinam , Arivazhagan Mani , Malecki Jan
Published: July 2018

A convenient strategy has been developed for the synthesis of structurally diverse novel 1,4-dihydropyridine frameworks bearing a 3-nitrophenyl moiety through a one-pot, four-component reaction with 4-(N,N-dimethylamino)pyridine as a catalyst at room temperature. This tandem process proceeds more effectively than previous catalytic processes.
Comparison of Outcomes After Percutaneous Coronary Intervention Between Calcified and Nonclacified Lesions
Authors: Satish K. , Sandeep M. , Indrani G.
Published: July 2018

Introduction: Coronary artery calcification increases with age and associated with significant major adverse cardiovascular events. The presence of calcification makes the percutaneous coronary interventions difficult and associated with peri-procedural complications. The main objective of our study is to evaluate the outcome of patients with calcific coronary lesions compared with non-calcific lesions.

Methods: Patients admitted in the cardiology department with either chronic stable angina or acute coronary syndrome who underwent percutaneous coronary interventions were included and divided into two groups, those who had calcific coronary lesions and non-calcific coronary lesions. Calcified lesions were made out by fluoroscopy during conventional angiogram as radiopacity at the site of the target lesion. We prospectively collected and compared the demographic, clinical data ( including risk factors), details of PCI procedure and in hospital outcomes(enzymatic infarcts - EI, vascular access complications –bleed or pseudo-aneurysm, contrast induced nephropathy - CIN, target vessel acute occlusion with or without heart failure – HF and mortality) between calcified and non-calcified lesions.

Results: A total of 439 patients were enrolled in the study of which 283 patients were in a calcific group and 156 patients were in non-calcific group. There was no significant difference among risk factors like DM and HTN (p=0.92, p=0.59) in between the both groups. Calcific coronary lesions had long lesions (mean lesion length -20.01 ±3.8mm in calcific, 18.3±3.9mm in non-calcific: p= 0.00) requiring longer stents (mean stent size and length- 3.08 ± 2.1 mm, 22.12 ± 7.95mm in calcific and 2.92± 0.38 mm, 20.5 ± 7.3mm in non-calcific group) compared to non-calcific lesions, which was statistically significant (p=0.02). In hospital complications like EI, HF and pseudo-aneurysm were more in the non-calcific group (n=19, p=0.02), whereas vascular site bleeding was higher in the calcific group. There was no significant difference between mortality between these groups.

Conclusion: There was no increased risk of in-hospital and peri-procedural complications in patients with calcific coronary artery lesions compared to non-calcific lesions, which also depends on other conditions like acuteness of presentation and left ventricular function.
Control of Thrombin Mediated Cleavage of Protein S
Authors: Mitchell Christina A , Hau Lena , Salem Hatem H
Published: July 2018

Thrombin has been shown to cleave the vitamin K dependent cofactor protein S with subsequent loss of its cofactor activity. This study examines the control mechanisms for thrombin cleavage of protein S.

The anticoagulant activity of activated protein C (APC) is enhanced fourteen fold by the addition of protein S. Thrombin cleaved protein S is seven fold less efficient than the native protein, and this loss of activity is due to reduced affinity of cleaved protein S for APC or the lipid surface compared to the intact protein.

In the absence of Ca++, protein S is very sensitive to minimal concentrations of thrombin. As little as 1.5 nM thrombin results in complete cleavage of 20 nM protein S in 10 min and loss of cofactor activity. Ca++, in concentrations greater than 0.5 mM, will inhibit this cleavage and in the presence of physiological Ca++ concentrations, no cleavage of protein S could be demonstrated in spite of high concentrations of thrombin (up to 1 μM) and prolonged incubations (up to two hours). The endothelial surface protein thrombomodulin is very efficient in inhibiting the cleavage of protein S by thrombin suggesting that any thrombin formed on the endothelial cell surface is unlikely to cleave protein S, thus allowing the intact protein to act as a cofactor to APC.

We conclude that the inhibitory effects of Ca++ and thrombomodulin on thrombin mediated cleavage of protein S imply that this event, by itself, is unlikely to represent a physiological control of the activity of protein S.
Von Willebrand Factor in Cultured Human Vascular Endothelial Cells from Adult and Umbilical Cord Arteries and Veins
Authors: Wachem Pauline B van , Reinders Jan Hendrik , Buul-Wortelboer Marijke F van , Groot Philip G de , Aken Willem G van , Mourik Jan A van
Published: July 2018

Endothelial cells were cultured from various human arteries and veins, obtained from adult individuals and from umbilical cords. We compared the storage and secretion of von Willebrand factor by endothelial cells from umbilical veins with that of endothelial cells cultured from a number of adult vessels, including aorta, arteria iliaca, vena saphena magna and vena cava. There were no differences in the way the cultured endothelial cells handled the von Willebrand factor they synthesized. Endothelial cells from the various vessels responded to stimuli in secreting stored von Willebrand factor. The cells also responded to thrombin and ionophore A23187 in producing enhanced amounts of prostacyclin. Thus, cultured umbilical vein endothelial cells have properties that are very similar to those of cultured endothelial cells of various other origins. It is concluded that foetal venous cells provide a representative model for studies of endothelial cell von Willebrand factor biosynthesis and prostacyclin production.
A Monoclonal Antibody that Recognizes the Receptor Binding Region of Human Urokinase Plasminogen Activator
Authors: Luisa Nolli Maria , Corti Angelo , Soffientini Adolfo , Cassani Giovanni
Published: July 2018

An anti-urokinase monoclonal antibody 5B4 (MAB 5B4) was obtained by fusing the murine myeloma cell line X63-Ag8.653 with the spleen cells from a female BALB/c mouse immunized with high-molecular-weight urokinase (HMW-uPA).

MAB 5B4 is an IgGl that binds selectively to the single-chain form of uPA (sc-uPA), to HMW-uPA and to the 17,000 Mr aminoterminal fragment of the A-chain (ATF) but not to the low-molecular-weight urokinase (LMW-uPA) nor to the reduced form of HMW-uPA. This strongly suggests that MAB 5B4 recognizes a conformational determinant on the A-chain.

The antibody has an affinity constant for uPA-Sepharose of 1.42 × 107 M−1, calculated from equilibrium binding data, and can be used for one step purification of HMW-uPA by immunoaffinity chromatography.

MAB 5B4 and the previously obtained antibody 105IF10 (16) recognize the A-chain: the epitopes, however, are distinct as shown by double-antibody-sandwich enzyme immunoassay.

Finally MAB 5B4 inhibits the binding of ATF to the uPA receptor of different human cells, whereas 105IF10 does not. Thus this antibody represents a potentially, useful tool for the study of uPA receptor physiology.
Dose Response Relationships of Anticoagulant Activities After Subcutaneous Administration of Two Low Molecular Weight Heparins in Healthy Individuals
Authors: Hellstern P , Kiehl R , Blohn G von , Köhler M , Meierhenrich U , Wenzel E
Published: July 2018

This study was performed to estimate appropriate dosages of two low molecular weight heparins (LMWH) for clinical trials on subcutaneous perioperative thrombosis prophylaxis. Anticoagulatory activities and platelet function were investigated after single doses of two LMWH and of unfractionated sodium heparin (UFH) in 24 healthy individuals. Twelve subjects received subcutaneous injections of 1000, 1500, and 2500 i.u. (aPTT) of LMHW 1, and the other 12 received LMWH 2 at same dosages. The following parameters were determined before 30 min, 1 h, 90 min, 2 h, 3 h, 4 h, 6 h, 8 h, and 10 h after either LMWH or 5000 i.u. (aPTT) UFH: aPTT, thrombin time, anti-Xa activity (S 2222, Coatest heparin), and anti-IIa activity (Chromozym TH). Bleeding time, platelet count, and adrenalin-, collagen-, and ADP-induced platelet aggregation were assessed before and 3 h after administration.

After application of 1500 i.u. LMWH 1 and LMWH 2, the anti-Xa and anti-IIa levels were already significantly higher than after 5000 i.u. UFH. 2500 i.u. LMWH 1 and LMWH 2 evoked significantly greater prolongations of aPTT and thrombin time values than did 5000 i.u. UFH. This was not the case after 1000 and 1500 i.u. LMWH. The half-lives of anticoagulatory effects after LMWH were markedly longer than after UFH. Platelet function was not altered by any of the heparins tested. Our results indicate that LMWH cause anticoagulatory effects in vivo that cannot be predicted by in vitro studies and that the appropriate single dosages of LMWH in subcutaneous perioperative thrombosis prophylaxis have to be estimated by dosage determinations in healthy subjects.
Epidemiology of Vestibular Impairments in a Pediatric Population
Authors: Quarez Juliette , Priol Audrey , Wiener-Vacher Sylvette
Published: July 2018

The purpose of this study was to report the prevalence of vestibular impairment (VI) in children (n = 2,528) referred for complete vestibular testing because of balance disorders (BD) or hearing loss (H). A VI was shown in 51.5% of the children tested (1,304/2,528). For BD (e.g., vertigo, dizziness, instability, delay in posturomotor development), VI was found in 36.5% (n = 379/1,037). The most frequent causes of BD with VI included inner ear malformation (13.5%), delay in posturomotor development (13.4%), hearing loss revealed with vertigo (3.9%), trauma (3.9%), vestibular neuritis (3.3%), meningitis (2.5%), Meniere-like syndrome (1.1%), BPPV posttrauma (1%), labyrinthitis (0.4%), and unknown etiology (19.6%). Normal responses to the complete battery of tests (n = 658, 63.5%) excluded a vestibular origin to BD, leading to other diagnoses: principally migraine (15.6%), ophthalmological disorders (15.1%), neurological disorders (including delay in posturomotor development; 14.4%), orthostatic hypotension, or somatoform dizziness (<1%). Of the children referred for hearing loss (n = 1,491), 68.5% were tested without cochlear implantation (CI; n = 1,022). In this group, 54.5% presented with VI (n = 557). This was mostly found in cytomegalovirus infection, inner ear malformation, and genetic syndromes. Profound hearing loss candidates for cochlear implants had complete bilateral vestibular loss in 20% and delay in posturomotor development, and 80% had partial or normal vestibular function and normal posturomotor development. VI was found after CI in 50% on the side of the implant (partial in 41% and complete in 9%). VI is present in 36.5% of children referred to our center for BDs and 54.5% for hearing loss. Vestibular testing permits ruling out peripheral VI and hence seeking other causes for BDs such as migraine and ophthalmological disorders and also helps lower the risk of inducing bilateral complete vestibular loss in CI protocols.
Quantitative Vestibular Function Testing in the Pediatric Population
Authors: Rodriguez Amanda , Janky Kristen
Published: July 2018

Quantitative tests of vestibular function include the caloric test, cervical and ocular vestibular evoked myogenic potential (VEMP), rotary chair, and head impulse test, either at the bedside or utilizing video head impulse test (vHIT). The purpose of this article is to provide an overview of how to perform these tests in children, including which tests are recommended based on the child's age and any modifications or considerations that can be made. A variety of clinical measures have been recommended as screening measures for vestibular loss, which will be reviewed. Symptom questionnaires designed to assess the functional impact of dizziness and vestibular loss in children will also be discussed. If a child complains of dizziness or if vestibular loss is suspected (either by case history or positive screening measure), vestibular function testing is warranted. For vestibular function testing, children aged 0 to 2 years typically receive rotary chair, cervical VEMP, and vHIT if a remote system is available. For children aged 3 to 7 years, vHIT, cervical VEMP, and ocular VEMP are completed, and for children aged 8+ years, vHIT, caloric testing if vHIT is normal, and cervical and ocular VEMP are completed. For all children, modifications to testing can be made, as needed.
Oculomotor Assessment in Children
Authors: McCaslin Devin , Doettl Steven
Published: July 2018

Oculomotor evaluation as part of videonystagmography is an integral tool in the assessment of vestibular function providing a global assessment of the neurological pathways associated with oculomotor function. The value of an oculomotor evaluation for pediatric evaluation is well established; however, many questions can also arise with the application to the pediatric population. Oculomotor function is age dependent which can have a significant effect on the test results obtain in children. The underlying neural substrates and age effects are discussed across the literature with specific results from recent research using clinical oculomotor equipment and protocols. The evidence suggests there are several key differences in the pediatric population compared with adults. These include longer saccade latencies, reduced smooth pursuit gain, increased optokinetic asymmetry, increased variability in all responses, and increased artifact in saccade and smooth pursuit testing.
Vestibular and Oculomotor Function in Children with Cerebral Palsy: A Scoping Review
Authors: Christy Jennifer , Vogtle Laura , Almutairi Anwar
Published: July 2018

Cerebral palsy (CP) is a nonprogressive permanent brain injury that causes an impairment of movement and posture. This scoping review aimed to answer the following questions: (1) “What is the status of oculomotor function in children with CP?” (2) “What is the status of vestibular function (i.e., gaze stability, perception of vertical, vestibular-related balance abilities) in children with CP?” Using Arksey's and O'Malley's five-stage framework, we searched six online databases for relevant articles. The inclusion criteria were: (1) participants of the studies included individuals with CP; (2) a primary outcome in the studies was measurement of oculomotor, vestibular, and/or balance; (3) studies were published within the past 20 years; and (4) the participants in the studies were between 0 and 21 years of age. Twenty-one articles were found that described impairments in oculomotor function (n = 9), vestibular function (n = 1), and oculomotor and vestibular integration (n = 11) in children with CP. The evidence suggests that children with CP may have altered saccadic and smooth pursuit eye movements, abnormal saccular function, poor eye–hand coordination, and abnormal use of vestibular information for balance. Future studies should explore peripheral and central vestibular function using reliable and valid methods for this population. This scoping review demonstrated a paucity of rigorous and objective research to describe the status of oculomotor and vestibular function in children with CP. However, preliminary studies suggest that more research is warranted.
Considerations for Testing and Treating Children with Central Vestibular Impairments
Authors: Christy Jennifer
Published: July 2018

This perspective explores common pediatric diagnoses that could present with central vestibular pathway dysfunction, leading to delays in motor development and postural control, and gaze instability. Specifically, the following diagnoses are considered: cerebral palsy, myelomeningocele, vestibular migraine, attention-deficit hyperactivity disorder, developmental coordination disorder, concussion, childhood cancer, congenital muscular torticollis, adolescent idiopathic scoliosis, and autism. Suggestions for clinical screening, vestibular function testing, and vestibular rehabilitation for children with these diagnoses are based on evidence for the efficacy of testing and interventions for children with peripheral vestibular hypofunction. More research is needed to explore peripheral and central vestibular function in children with these diagnoses. Testing and intervention methods may need to be modified to accommodate for the specific behavior and motor challenges that some children might present. Researchers should develop technology so that gaze stabilization exercises can be delivered in a fun, functional, and effective way.
Begutachtung psychischer Erkrankungen in der gesetzlichen Renten- und Unfallversicherung
Authors: Dreßing Harald , Förster Klaus , Schneider Frank
Published: July 2018

Psychiatrischer Sachverstand ist bei einer Vielzahl von gerichtlichen Gutachtenaufträgen nötig. Psychiatrische Gutachten erfordern eine hohe fachliche Kompetenz und Grundkenntnisse in den Rechtsgebieten, in denen das Gutachten zu erstatten ist. In der Arbeit werden allgemeine Rahmenbedingungen der Begutachtung dargestellt, die Rolle des Gutachters definiert sowie exemplarisch einige Grundregeln der Begutachtung im Bereich der gesetzlichen Rentenversicherung und der gesetzlichen Unfallversicherung vorgestellt. Darüber hinaus finden sich Ausführungen zur Problematik von Aggravation und Simulation.
Demenz bei Down-Syndrom: Ein häufiger psychiatrischer Vorstellungsgrund
Authors: Kruse Björn , Heinrich Manuel , Diefenbacher Albert , Kaiser Heika , Sappok Tanja
Published: July 2018

Einleitung Diese Studie untersucht die Prävalenz und klinischen Charakteristika von Demenzen bei psychiatrisch vorgestellten Erwachsenen mit Down-Syndrom und leitet Konsequenzen für die klinische Praxis ab.

Methodik Die Patientenmerkmale und Prävalenz von Demenz wurden retrospektiv (2005–2012, N = 75) bei Erwachsenen mit Down-Syndrom im klinisch-psychiatrischen Setting untersucht.

Ergebnisse Bei jedem 3. Patienten mit Down-Syndrom wurde – in der Regel erst nach einer Verlaufsuntersuchung von 6 bis 12 Monaten – eine Demenz diagnostiziert. Patienten mit Demenz waren älter und häufiger weiblich, während sich der Grad der Intelligenzminderung nicht unterschied. Die Schilddrüsen- und Calciumwerte waren bei Menschen mit wie ohne Demenz häufig auffällig.

Diskussion Demenz ist ein häufiger psychiatrischer Vorstellungsgrund bei Menschen mit Down-Syndrom, insbesondere bei Frauen und im höheren Lebensalter. Die Versorgungsstrukturen in Deutschland sollten bedarfsgerecht angepasst werden.
Drugs in Pregnancy and Lactation – Medications Used in Swiss Obstetrics
Authors: Schenkel Larissa , Simões-Wüst Ana , Hösli Irene , von Mandach Ursula
Published: July 2018

Background In order to improve the safety for drugs in pregnancy and lactation, data on the clinical practice must be collected and validated.

Methods Data on the medications routinely used were requested from the university hospitals for obstetrics and the non-university perinatal centres in Switzerland and recommendations and guidelines of scientific societies for the various fields of application were sought.

Results Part I: For during pregnancy and the peripartal period respectively, 69 and 21 different active constituents of medications were identified from at least 4 centres. For during pregnancy, the active constituents used in most of the centres are nifedipine, iron i. v. and oral, labetalol and magnesium sulphate, amoxicillin with clavulanic acid, paracetamol, dalteparine, metoclopramide as well as atosiban and hexoprenaline; for during the peripartal period betamethasone, misoprostol, oxytocin, clindamycin as well as fibrinogen, sulprostone and tranexamic acid were most frequently cited. Recommendations of various scientific societies were found primarily for pregnancy-specific fields of application.

Conclusion The same active constituents of medications are consistently used in Swiss perinatal centres for the main indications in pregnant women. Despite the existing experience and available evidence, they are mainly used off-label. Official authorisations for frequently or consistently used active ingredients should be granted.
The possibility and desirability of replication in the humanities
Authors: Peels Rik , Bouter Lex
Published: July 2018

In this article, we argue that the debate on the poor reproducibility of scientific research has overlooked an entire field: replication is also possible and desirable in the humanities. So far, the debate on replicability has been carried out primarily in the biomedical, natural and social sciences. It turns out that, for a wide variety of reasons, many of which lead to selective reporting, a large proportion of studies in these fields are not replicable, sometimes as many as 70 percent. In this paper, we leave these fields mostly aside, since they have been extensively addressed in the recent literature, and turn to the humanities. First, we distinguish between replicability and replication. Subsequently, we defend the view that replication is entirely possible in the humanities: it meets all the criteria that have been identified for biomedical, natural and social science research. The uniqueness of many research objects in the humanities does not present an obstacle to this. We also explain why replication is desirable and urgently needed in the humanities. Finally, we give various practical guidelines for how replication in the humanities could be carried out, such as focusing on the replication of cornerstone studies or a random selection of published research in a sub-discipline, and opting, if possible, for a conceptual replication, so that triangulation becomes possible.
Influence of voltage duty ratio on current asymmetry and mode of a helium dielectric-barrier discharge excited by a modulated voltage
Authors: Li Xuechen , Liu Rui , Jia Pengying , Wu Kaiyue , Ren Chenhua , Kang Pengcheng , Jia Boyu , Li Yaru
Published: July 2018

Excited by a modulated sinusoidal voltage, dielectric barrier discharge in atmospheric pressure helium has been investigated through a one-dimensional fluid model. Under a lower voltage amplitude, the discharge presents one current pulse per half sinusoidal cycle. The positive discharge is weaker than the negative one if the duty ratio of the modulated voltage is lower. When increasing the duty ratio, the intensity of the positive discharge increases and that of the negative discharge keeps approximately constant, which implies that the discharge symmetry is improved. A similar phenomenon regarding the discharge symmetry is also observed under a higher voltage amplitude despite the fact that a secondary discharge following a primary one is presented per half sinusoidal cycle. Besides the duty ratio, the discharge symmetry can be improved by increasing the voltage amplitude, especially under a lower duty ratio. These phenomena are qualitatively explained by analyzing the variation of the electron density when increasing the duty ratio. Results also indicate that the positive primary discharge at the peak moment belongs to a Townsend mode or a glow one, which is determined by the duty ratio and the voltage amplitude. Finally, the critical voltage for the Townsend mode transiting to the glow one is investigated as a function of the duty ratio.
High Reynolds number incompressible turbulent flow inside a lid-driven cavity with multiple aspect ratios
Authors: Samantaray Debabrat , Das Manab Kumar
Published: July 2018

The numerical simulation of incompressible turbulent flow at Re = 11 800 (equivalent Reynolds number Rem = 10 030) inside lid-driven cavities with varying spanwise aspect ratio and depthwise aspect ratio (DAR) has been carried out using the dynamic Smagorinsky model. A better comparison of central line averaged velocities and second order turbulent properties is obtained with the existing experimental result of Prasad and Koseff [“Reynolds number and end-wall effects on a lid-driven cavity flow,” Phys. Fluids A 1, 208–218 (1989)] than with the one provided by Leriche and Gavrilakis [“Direct numerical simulation of the flow in a lid-driven cubical cavity,” Phys. Fluids 12, 1363–1376 (2000)]. It is noticed that the size of the downstream secondary vortex increases with an increase in the aspect ratio. Lower DAR cavities are found to be having the maximum turbulent kinetic energy (TKE) and turbulent production, which is further confirmed by the TKE spectra shown at the point of maximum turbulent production on the symmetrical mid-plane. The power spectra maintain a slope of −53 in the inertial subrange as proposed by Kolmogorov and show a steeper slope in the dissipating range. The time integral scale shows that in low DAR cavities, eddies are formed and undergo complete distortion more frequently. The joint probability density function confirms the anisotropy in turbulence, and the anisotropy invariant map (Lumley triangle) shows the type of turbulent anisotropy which shows whether the turbulence is either one-component or two-component near the walls.
Effects of the cooperative interaction on the diffusion of hydrogen on MgO(100)
Authors: Castelli Ivano E. , Soriga Stefan G. , Man Isabela C.
Published: July 2018

Understanding hydrogen diffusion is important for applications such as hydrogen storage and spillover materials. On semiconductors, where paired electron acceptors and donors stabilize each other, the hydrogen diffusion depends on the number of adsorbed fragments. Using density functional theory, we investigate the effects of preadsorbed hydrogens on activation energy and reaction path for hydrogen diffusion on MgO(100): the presence of an unpaired hydrogen causes a diffusion, on O-sites, above the surface with a lower activation energy compared to the case of paired hydrogens where the diffusion distorts the surface. This effect is missing for diffusion on Mg-sites.
Effects of Reynolds number and thickness on an undulatory self-propelled foil
Authors: Zhang Dong , Pan Guang , Chao Liming , Zhang Ya
Published: July 2018

The effects of the Reynolds number (Re) and thickness on an undulatory self-propelled foil were numerically investigated using the immersed boundary method. Re varied from 50 to 2 × 105, which encompasses the viscous, intermediate, and inertial regimes using a NACA 0012 airfoil. An investigation of the thickness was performed on NACA airfoils with maximum thicknesses of 0.04 ∼ 0.24 at two Re values (5 × 104 and 500). The results indicated that the foil can achieve a higher forward velocity, perform less work, and exhibit a higher propulsive efficiency with increasing Re. However, the effect of Re is asymptotic beyond 5 × 104. Four types of vortex structures exist, and the transition from one regime to another is closely related to hydrodynamic changes. In the thickness study, thinner foils outperformed thicker foils in terms of the forward velocity and input power at both Re values. However, the efficiency related to the conversion of input power into kinetic energy for NACA 0004 was the lowest. An optimum thickness exists that depends on Re. At higher Re, the vortical structure differs for each thickness with the deflection angle, whereas at low Re, the location of the separation point strongly influences the hydrodynamics.
Edge toroidal charge exchange spectra analysis in the EAST
Authors: Jiang D. , Li Y. Y. , Fu J. , Zhang L. , Zhou Y. X. , Tao W. , Chen Z. , Lyu B. , Gao X. , Xu G. S.
Published: July 2018

An edge toroidal charge exchange recombination spectroscopy (eCXRS) diagnostic has been deployed successfully on the Experimental Advanced Superconducting Tokamak (EAST) recently, providing edge plasma ion temperature and toroidal rotation. Edge CXRS on EAST typically monitors the carbon vi (529.059 nm, n = 8 → 7) spectral line. Spectral lines emitted from other different impurities that appeared in the wavelength ranges of 528 nm–530 nm illustrate the need to revise the edge change exchange spectra analysis in this region. Since the eCXRS sightlines end on the ion cyclotron range of frequencies (ICRF) stainless steel antenna, the passive Fe lines coming from the antenna could be recorded by eCXRS diagnostic when ICRF is used. A revised edge toroidal charge exchange spectra analysis including Fe spectral lines is presented. The accuracy of eCXRS measurement has been improved by the revised spectra analysis.
Soft X-ray emission from laser-irradiated gold foils
Authors: Davis J. S. , Drake R. P. , Fraenkel M. , Frank Y. , Keiter P. A. , Klein S. R. , Raicher E. , Shvarts D. , Trantham M. R.
Published: July 2018

This paper reports measurements of soft-x-ray emission from gold foils irradiated by 6 ns laser pulses, and analysis and simulations of the observations. These foils can be used as x-ray sources to drive a wide range of experiments. A multichannel, photodiode array measured the time-resolved, soft-x-ray emission. A soft-x-ray framing camera imaged the emission in selected energy bands. Foil thicknesses were from 0.5 to 1.5 μm. The imaging data show that the region emitting soft x-rays grows throughout the laser drive, on both the front and rear surfaces. Analysis of the emitted radiation flux from the rear surface, taking the time-dependent spot size into account, showed that the peak effective temperature of 0.5-μm-thick foils is near 88 eV, while that of 0.75-μm-thick foils is near 78 eV. A Monte Carlo method was used to evaluate the component of the uncertainty in the effective temperature introduced by variations in signal voltages and by uncertainty in the size of the emitting spot. This was found to be near ±2 eV in most cases. Simple theoretical considerations explain the main features of the observations. The Florence code, working with atomic physics from sophisticated models, proved able to reproduce the main features of the observed spectra with 1D simulations in which the laser energy flux was adjusted on the basis of the observed lateral spreading of energy.