bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magma‐Fluid Interactions Beneath Akutan Volcano in the Aleutian Arc Based on the Results of Local Earthquake Tomography
Authors: Koulakov Ivan , Komzeleva Viktoria , Smirnov Sergey Z. , Bortnikova Svetlana B. 
Published: February 2021

AbstractAkutan Island hosts a volcano considered as one of most active in the Aleutian Arc. We build a new tomography model including the 3D distributions of the Vp, Vs, and Vp/Vs ratio based on arrival time data from more than 4,000 local earthquakes recorded by 13 seismic stations. In this model, we reveal a columnar anomaly of high Vp, low Vs, and high Vp/Vs ratio with a top boundary at a depth of ∼6 km below sea level, which represents a steady conduit feeding the Akutan volcano. In the upper part of the tomographic model, the highly heterogeneous structures are associated with interactions of shallow magmatic sources, meteoric and magmatic fluids, as well as degassing. Beneath the summit area of Akutan, we observe a prominent anomaly of high Vp/Vs, which may represent a shallow magma reservoir directly responsible for recent eruption activity and ongoing gas emission through the summit fumarole. The other fumarole field at the eastern flank of the volcano appears to be associated with a seismically active zone of low Vp/Vs ratio at depths of 2–4 km below surface. These structures indicate different depths of magma degassing in these two areas, which may explain distinct geochemical features of emitted gases. Besides the prominent anomaly representing the shallow magma reservoir beneath the caldera and the active cone, we observe several areas with high Vp/Vs ratio, some of which are interpreted as shallow magma storage regions, and some as zones of meteoric water penetration.
Upper Ocean Stratification in the Eastern Pacific During the SPURS‐2 Field Campaign
Authors: Katsura S. , Sprintall J. , Bingham F. M. 
Published: February 2021

AbstractThe region between a shallow mixed layer and a deep isothermal layer resulting from salinity stratification is called a barrier layer (BL). Since BLs hinder the surface heat and momentum exchange with the ocean subsurface, they play an important role in air‐sea interaction. Synoptic features and formation of BLs and associated temperature inversions (TIs) in the Eastern Pacific Fresh Pool (EPFP) were investigated using shipboard observations. BLs and TIs were found in the high‐precipitation EPFP, a frontal transition zone (FTZ) and in the sea surface salinity (SSS) front during a 2016 boreal summer cruise. During a 2017 boreal autumn cruise, BLs and TIs were found from the southern part of the EPFP to the SSS front. The BLs in the SSS front and the FTZ were meridionally displaced from the precipitation maximum during both the 2016 and 2017 cruises. Freshening and cooling by tilting of both the isohalines and isotherms of the SSS front occurred via Ekman and geostrophic flow during both cruises, and also within the EPFP during 2016. The SSS front was a dominant contributor to the density gradient in the horizontal plane. A high dissolved oxygen content observed within BLs confirmed that the surface flow plays an important role in the BL and TI formation through the tilting process. Patchy distribution of freshening and cooling by tilting implies an intermittent BL and TI formation with short time scales.
Numerical Study of Near‐Surface Jet in the Atmospheric Surface Layer Over an Oceanic Temperature Front
Authors: Deng Bing‐Qing , Zhao Ming‐Xiang , Wang Qing , Shen Lian 
Published: February 2021

AbstractThe interaction between atmospheres and oceans plays an important role in the global climate. In a field experiment of atmospheric flows over the Gulf Stream, when the wind blew from the cold water to the warm water, we observed a near‐surface jet over the warm water. We then conducted direct numerical simulations and large‐eddy simulations of atmospheric turbulence in the vicinity of the front and captured the near‐surface jet in simulations for the first time. Analyses of the data obtained from the high‐resolution three‐dimensional simulations revealed the dominant generation mechanisms of the near‐surface jet, which are the strong vertical mixing by the enhanced streamwise rolls and the mean downward motion. Around the near‐surface jet, the magnitude of the negatively valued Richardson number significantly increases, indicating the dominance of buoyancy effects in the flow dynamics there. The development of the near‐surface jet suggests that the Monin‐Obukhov similarity theory (MOST) needs to be modified in representing marine atmospheric boundary layers over sea surface temperature fronts.
Impact of Land Surface Processes on a Record‐Breaking Rainfall Event on May 06–07, 2017, in Guangzhou, China
Authors: Gao Zhibo , Zhu Jiangshan , Guo Yan , Luo Neng , Fu Yuan , Wang Tiantian 
Published: February 2021

AbstractA record‐breaking extreme rainfall event with a maximum rainfall amount over 24 h of 524.1 mm occurred in Guangzhou, China, on May 06–07, 2017. To study the impact of land surface processes on this extreme rainfall, two 21‐member convective‐permitting ensemble forecasts over South China were performed based on two land surface models (LSMs), Noah and Community Land Model (CLM), and 21 forecasting members of the Global Ensemble Forecast System (GEFS). The results showed that, in general, members using the Noah LSM could better simulate urban heat islands (UHIs) and urban convection than members using the CLM LSM in this case. By investigating the ensemble member that most resembled the observations, it was found that the high temperature center in the urban area caused a thermal low in the early stage. As the southerly winds strengthened, the low‐level convergence line continued moving northward and eventually triggered convection in the mountainous region. A sensitivity experiment showed that the impact of land surface heterogeneity on precipitation could be reflected on a finer scale, and heavy rainfall was very sensitive to the changes in small‐scale land surface forces, including terrain and land use. Slight variations in small‐scale land surface conditions caused great responses in the total precipitation, indicating that for the occurrence of such quasi‐stationary extreme rainfall, a subtle balance between different atmospheric and land surface factors may be required.
Persistent Provenance of South Asian Monsoon‐Induced Silicate Weathering Over the Past 27 Million Years
Authors: Ali Sajid , Hathorne Ed C. , Frank Martin 
Published: February 2021

AbstractThe development of the South Asian monsoon (SAM) and Himalaya‐Tibetan Plateau uplift were closely intertwined with some studies suggesting that uplift initiated the monsoon whereas others link tectonics with monsoon‐controlled exhumation. Silicate weathering controls atmospheric CO2 on geological timescales resulting in a large potential for monsoon strength and the Himalayan orogeny to influence global climate but detailed records of SAM‐induced weathering on million year (Myr) timescales are lacking. Here, we present radiogenic Sr, Nd, and Pb isotope compositions of clay minerals produced by silicate weathering and transported to the central Bay of Bengal. The radiogenic isotope data exhibit a relatively small range and demonstrate a remarkably consistent mixture of sources dominated by Himalayan rocks and the Indo‐Burman ranges, which consist of sediments derived from the Himalayas. This suggests that the spatial pattern of regional weathering, which today is highest in the regions of strongest monsoon rains, has persisted in a similar form for the last 27 Myrs. A pronounced increase in primary clay mineral abundance (from 9% to 22%) coincident with global cooling 13.9 Myrs ago points to a shift in the weathering regime given that the clay provenance did not change dramatically. Relatively weaker chemical weathering intensity during the mid and late Miocene cooling suggests increased aridity and changes in the large scale atmospheric circulation in the SAM domain. The establishment of the dry winter monsoon season during the mid and late Miocene may have caused this shift in the weathering regime and can reconcile much of the contrasting evidence for SAM initiation.
Novel handover scheme for indoor VLC systems
Authors: Younus Safwan Hafeedh , Al‐Hameed Aubida A. , Hussein Ahmed Taha 
Published: February 2021

AbstractManaging mobility in visible light communication systems is one of the main encounters that requires to be tackled. In this paper, we propose subcarrier multiplexing tones as control signals for handover in visible light communication systems. These control tone signals are unmodulated signals, and each light unit is given a unique unmodulated control signal. One light unit is used to send the data to the user, which is the best light unit. At a receiver side, band pass filters are used to separate subcarrier multiplexing tones. This enables receiver to connect with all light units via subcarrier multiplexing tones. The carrier to noise ratio of each control tone signal is estimated at the receiver, which leads to make the receiver connects with the light unit that offers the best connection during its mobility.
Novel grid‐forming control of PMSG‐based wind turbine for integrating weak AC grid without sacrificing maximum power point tracking
Authors: Li Yujun , Yuan Xiaotian , Li Jiapeng , Xiao Huangqing , Xu Zhao , Du Zhengchun 
Published: February 2021

AbstractTraditional permanent magnet synchronous generator (PMSG)‐based wind turbine (WT) normally utilises phase lock loop (PLL) for obtaining accurate phase angle of AC grid to make sure of maximum power point tracking (MPPT). However, a weak AC system with a low short circuit ratio (SCR) and high control bandwidth of PLL might have impaired effects on the stability of the system. To overcome these, a novel power synchronous control of PMSG‐based WT with grid forming ability of PMSG for integrating very weak AC system is first proposed in this study. Grid‐side converter (GSC) of PMSG emulates the inertia response of synchronous generator (SG) by artificially coupling the DC‐link voltage with the grid frequency based on the certain droop property, while the converter voltage magnitude is regulated according to DC‐link voltage deviation by controlling the modulation index of GSC. This novel scheme can realise the grid synchronisation without PLL by mimicking the natural characteristic of SG. Small‐signal analysis of the proposed scheme indicates the DC‐link capacitor energy can be exerted for system inertia support during system disturbances, while the system damping can be provided by spontaneously alternating converter voltage magnitude. More importantly, MPPT property of PMSG is not compromised while providing inertia and damping for the system, and the related inertia and damping coefficient of WT with the proposed control can be easily tuned for satisfying the system requirement. Non‐linear simulations of one PMSG connected with one large SG considering a sudden change of active power reference and variable wind speeds have been studied to verify the effectiveness of the proposed grid‐forming control.
Design and HIL implementation of a new robust fractional sliding mode control of microgrids
Authors: Delavari Hadi , Naderian Sina 
Published: February 2021

Microgrid inverters in the presence of faults, unavoidable modelling uncertainties, disturbance and harmonic current resulting from nonlinear loads should have small steady state tracking error, small THD and high robustness hence this subject has turned one of the motivations of this investigation. To achieve the stated goals, fractional adaptive sliding mode controller (FASMC) is proposed in this paper. The proposed controller increases the robustness, flexibility and degree of freedom. As far as in practice it is not easy to define the bounds of disturbances and guarantee the system stability, hence in next step, to overcome this challenge the adaptation laws are suggested. Then for the problem of determining the controller parameters, Particle Swarm Optimization (PSO) algorithm is used. The performance of the proposed technique is investigated for an islanded microgrid under different disturbances, also to verify the advantages of the proposed controller, the results are compared with other controllers. Finally, the proposed controller and PID controller are implemented experimentally on Arduino mega 2560 microcontroller.
Compensation voltage moduli comparison‐based wide‐area protection algorithm independent of data synchronism and integrity
Authors: Lin Xiangning , Ma Shumin , Jin Neng , Tong Ning , Chen Le , Li Zhengtian , Rong Zirui , Zhang Peifu 
Published: February 2021

Secondary direct‐current loss within a substation is a severe event. In China, each line protection device is generally powered by one set of secondary direct current (DC) power system within a substation of 110 kV voltage level. In this case, the line protection devices will be immediately taken out of service when the secondary DC is lost, and the lines protected by them will lose their corresponding protections. Once a fault occurs on the line, only the remote back‐up protection can be relied on to isolate the fault, which expands the fault influence and increases its clearance time. To handle the above problem, a novel wide‐area protection algorithm based on compensation voltage moduli comparison is proposed, which is independent of multi‐terminal data synchronism. Then, a comprehensive protection strategy composed of the proposed protection algorithm and the original local distances protection is proposed. The results from a power systems computer aided design/electromagnetic transients including DC (PSCAD/EMTDC)‐based simulation verify that the proposed protection algorithm has higher sensitivity. The comprehensive protection strategy could cope with most line faults effectively, even if only partial data are available, the selectivity and speed of which are better than that of distance protections.
High step‐up interleaved zero‐voltage transition DC–DC converter with coupled inductors
Authors: Mirzaei Amin , Rezvanyvardom Mahdi , Mekhilef Saad 
Published: February 2021

A high step‐up DC–DC converter which is applied to a voltage lift capacitor and coupled inductors to increase the voltage gain is proposed in this study. Moreover, the interleaved structure is applied in the converter to decrease the input ripple current. Besides, the voltage stress across the main and auxiliary switches is low. Furthermore, all switches and diodes have the soft‐switching condition by using an active clamp auxiliary cell. Consequently, the proposed converter has a high efficiency which is ideal for photovoltaic applications. Energy stored in the coupled inductors is transferred to the voltage lift capacitors and then transmitted to the output. Therefore, no voltage spikes caused by leakage inductors are created on the main switches. The converter operates in continuous current mode and its control remains in pulse width modulation. A 210 W laboratory prototype of the converter with 40 V input voltage and 420 V output voltage under 100 kHz switching frequency is constructed and experimental results confirm the theoretical analysis. Low voltage stress, low input ripple current and high efficiency (96.5%) show the superiority in the operation of the proposed converter in comparison with other similar structures.
Mehr Zeit für Patienten
Authors: Schwoerer Barbara , Schuster Julia 
Published: February 2021

ZUSAMMENFASSUNGUm aktuellen und zukünftigen Entwicklungen des deutschen Gesundheitswesens zu begegnen, hat das KfH Kuratorium für Dialyse und Nierentransplantation e. V. als größter gemeinnütziger Dialyseanbieter in Deutschland das Programm „Mehr Zeit für Patienten“ entwickelt. Es hat die Intention, die Mitarbeiter und Mitarbeiterinnen dazu zu befähigen, dass sie eigenverantwortlich ihre Arbeitsplätze gut organisieren und die Arbeitsabläufe innerhalb ihres Teams sowie die Zusammenarbeit mit anderen Bereichen verbessern. Hierbei wird das Ziel verfolgt, die Veränderung mit der Kraft und den Ideen aller zu gestalten, um am Ende mehr Zeit für die originäre Aufgabe der Pflege – die unmittelbare Arbeit am Patienten – zu erhalten. In einer modularen Weiterbildung wird den Teilnehmern des Programms zunächst die hierfür notwendige Methoden- und Moderationskompetenz vermittelt. Erste Ergebnisse zeigen: Mit der Einführung des Systems verbessern sich Zusammenarbeit und Kommunikation im Team. Wichtig für eine erfolgreiche Umsetzung ist es, zu Beginn kleine Schritte in Richtung der kontinuierlichen Verbesserung zu gehen und diese nachhaltig auszubauen. Der Erfolg wird sich dann einstellen, wenn die Führungskräfte es verstehen, jeden im Team zu motivieren und für das Thema zu begeistern.
Rationale Therapie mit Erythrozytenkonzentraten – Update 2020
Authors: Schoenes Bernd , Schrezenmeier Hubert , Welte Martin 
Published: February 2021

ZusammenfassungDer Einsatz von Erythrozytenkonzentraten muss dem Gebot einer rationalen Indikation folgen. Um dies weiter zu gewährleisten, wurden die 2009 publizierten und zuletzt 2014 in Teilen revidierten „Querschnitts-Leitlinien zur Therapie mit Blutkomponenten und Plasmaderivaten“ 1 der Bundesärztekammer 2020 einer systematischen Novellierung unterzogen. Der Artikel stellt sie vor.
Anatomie der V. saphena magna und parva
Authors: Mendoza Erika 
Published: February 2021

ZusammenfassungIn der Phlebologie ist die Varikose die häufigste Erkrankung. Dabei sind die V. saphena magna und V. saphena parva meist in die pathologische Rezirkulation involviert. Ihre Anatomie ist relativ konstant, bis auf Feinheiten im Mündungsbereich und Verlauf, die jedoch in einer Zeit, in der es verschiedene Techniken und Strategien zur Behandlung der Varikose gibt, mit ins Kalkül gezogen werden müssen. Somit kann man es erlauben, den Patienten den möglichst nebenwirkungsarmen Eingriff mit der geringsten Rezidivhäufigkeit anzubieten. Der Ultraschall ist heute der Goldstandard in der Untersuchung der Beinvenen; daher muss die Anatomie der Venen immer auch im Ultraschall verstanden werden. Der Artikel beleuchtet schematisch die Anatomie und ergänzt die Beschreibung mit typischen Schallbildern zur V. saphena magna und parva.
Wirkungsaussagen auf Websites: Abmahnfallen vermeiden!
Authors: Heinz-Georg Bramhoff 
Published: February 2021

SummarySachbezogene und differenzierte Therapieinformationen auf Heilpraktiker-Websites vermitteln – im Gegensatz zu überschwänglichen Wirkungsaussagen – Nutzern und potenziellen Abmahnern die erforderliche Seriosität. Sofern – wie bei den meisten naturheilkundlichen Verfahren – für die angestrebte Wirkung keine Evidenz vorliegt, muss dies in Zusammenhang mit der Therapieinformation entsprechend dargestellt werden. Absolute Therapieaussagen wie „korrigiert Fehlstellungen“ müssen ersetzt werden durch Formulierungen wie „kann nach Beobachtungen einzelner Therapeuten oftmals Fehlstellungen korrigieren“.
Erfahrungen zur Gewalt gegen Rettungskräfte – aus der Sicht des DRK
Authors: Sefrin Peter , Händlmeyer Annette , Stadler Thomas , Kast Wolfgang 
Published: February 2021

ZusammenfassungBerichte über Gewalt gegen Rettungskräfte werden immer häufiger. Vor diesem Hintergrund sollten spezielle Faktoren eruiert werden. Im Jahr 2019 führte das Deutsche Rote Kreuz (DRK) eine Umfrage zum Thema Gewalt gegen Einsatzkräfte im Rettungsdienst durch. In insgesamt 425 Fragebogen berichteten Einsatzkräfte über mindestens eine Gewaltanwendung in den vergangenen 12 Monaten. Ziel der Befragung war nicht die Erfassung der konkreten Anzahl der Übergriffe, sondern das Gewinnen von Angaben zu den Rahmenbedingungen. Die betroffenen Rettungsdienstmitarbeiter
1
waren zu 73,4% männlich und überwiegend in der Altersgruppe der 18 – 29-Jährigen. Es waren sowohl Notfallsanitäter (29,4%), Rettungsassistenten (14,8%) und Rettungssanitäter (33,6%) als auch weitere Rettungsdienstmitarbeiter betroffen. Die Übergriffe waren hauptsächlich verbal (40,3%). Der Anteil der tätlichen Gewalt betrug 14,4%. Die körperlichen Angriffe ereigneten sich meist
seltener als 1 – 2-mal pro Monat (83,8%), während die verbalen Angriffe oft häufiger erfolgten. Jeder 2. Angriff passierte im innerstädtischen Bereich (52,2%), wobei sozial problematische Wohngebiete vordergründig waren. Die Verteilung ist jedoch abhängig von Orten mit verschiedenen Einwohnerzahlen. Am häufigsten fanden die Gewaltanwendungen abends und nachts statt, meist während der Versorgung des Patienten (56,7%). Der Täter war in drei Viertel der Fälle der Patient selbst, jedoch zu gleichen Teilen auch Freunde (42,6%) und Angehörige (40,7%). Ein Schwerpunktort der Übergriffe sind unabhängig von der Größe der Orte Großveranstaltungen. Soweit feststellbar spielten Alkohol und Drogen eine wesentliche Rolle. Die Folge seitens der Betroffenen war bei 2,1% eine so schwere Schädigung, dass sie zu einer Krankschreibung von 1 Tag und im Extremfall bis zu 40 Tagen führte. In jedem 2. Fall wurde die Polizei entweder aufgrund des Meldebildes oder durch den Rettungsdienst vor Ort
alarmiert. 76% der Betroffenen wünschen eine gesonderte Schulung im Umgang mit Gewalt im Rahmen der Fortbildung. Das Mittel der Wahl seitens der Politik zur Verbesserung der Situation ist nach Meinung der Rettungsdienstmitarbeiter die Anhebung der pekuniären Strafen. Eine weitere Strafverschärfung scheint vor dem Hintergrund des Täterprofils und der Umgebungsbedingungen und der bei der in der Bevölkerung teilweise bestehenden Respektlosigkeit kein gangbarer Weg zu sein. Inwieweit eine intensivere Aufklärung zu einer Verbesserung der Situation führen kann, kann derzeit nur vermutet werden. Aus den Ergebnissen abgeleitet wurden Forderungen für die Zukunft erhoben.
Gender disparities in advanced endoscopy fellowship
Authors: Yu Jessica X. , Berzin Tyler M. , Enestvedt Brintha , Anderson Michelle A. , Popov Violeta B. , Thompson Christopher C. , Schulman Allison R. 
Published: February 2021

Abstract
Background and study aims Women remain underrepresented in gastroenterology, especially advanced endoscopy. Women represent 30 % of general gastroenterology fellows; yet in 2019, only 12.8 % of fellows who matched into advanced endoscopy fellowship (AEF) programs were women.
Methods We administered a web-based survey to the program directors (PDs) of AEF programs that participated in the 2018–2019 American Society for Gastrointestinal Endoscopy (ASGE) match. We assessed PD and program characteristics, in addition to perceived barriers and facilitators (scale 1–5, 5 = most important) influencing women pursuing AEF training.
Results We received 38 (59.3 %) responses from 64 PDs. 15.8 % (6/38) of AEF PDs and 13.2 % (5/38) of endoscopy chiefs were women. By program, women represented 14.8 % (mean) ± 17.0 % (SD) of AEF faculty and 12.0 % (mean) ± 11.1 % (SD) of AEF trainees over the past 10 years. 47.4 % (18/38) programs reported no female advanced endoscopy faculty and 31.6 % (12/38) of programs have never had a female fellow. Percentage of female fellows was strongly associated with percentage of female AEF faculty (ß = 0.43, P < 0.001). Inflexible hours and call (mean rank 3.3 ± 1.1), exposure to fluoroscopy (2.9 ± 1.1), lack of women endoscopists at national conferences/courses (2.9 ± 1.1) and lack of female mentorship (2.9 ± 1.0) were cited as the most important barriers to recruitment.
Conclusion We utilized a survey of AEF PDs participating in the ASGE match to determine program characteristics and identify contributors to gender disparity. Women represent a minority of AEF PDs, endoscopy chiefs, advanced endoscopy faculty and AEF trainees. Our study highlights perceived barriers and facilitators to recruitment, and emphasizes the importance of having female representation in faculty, and leadership positions in endoscopy.