bluuebunny/crossref_metadata_2025 huggingface dataset:
Refining pulsar radio emission due to streaming instabilities: Linear theory and PIC simulations in a wide parameter range
Authors: Manthei Alina C. , Benáček Jan , Muñoz Patricio A. , Büchner Jörg
Published: March 2021

Context. Several important mechanisms that explain coherent pulsar radio emission rely on streaming (or beam) instabilities of the relativistic pair plasma in a pulsar magnetosphere. However, it is still not clear whether the streaming instability by itself is sufficient to explain the observed coherent radio emission. Due to the relativistic conditions that are present in the pulsar magnetosphere, kinetic instabilities could be quenched. Moreover, uncertainties regarding specific model-dependent parameters impede conclusions concerning this question.

Aims. We aim to constrain the possible parameter range for which a streaming instability could lead to pulsar radio emission, focusing on the transition between strong and weak beam models, beam drift speed, and temperature dependence of the beam and background plasma components.

Methods. We solve a linear relativistic kinetic dispersion relation appropriate for pulsar conditions in a more general way than in previous studies, considering a wider parameter range. In doing so, we provide a theoretical prediction of maximum and integrated growth rates as well as of the fractional bandwidth of the most unstable waves for the investigated parameter ranges. The analytical results are validated by comparison with relativistic kinetic particle-in-cell (PIC) numerical simulations.

Results. We obtain growth rates as a function of background and beam densities, temperatures, and streaming velocities while finding a remarkable agreement of the linear dispersion predictions and numerical simulation results in a wide parameter range. Monotonous growth is found when increasing the beam-to-background density ratio. With growing beam velocity, the growth rates firstly increase, reach a maximum and decrease again for higher beam velocities. A monotonous dependence on the plasma temperatures is found, manifesting in an asymptotic behaviour when reaching colder temperatures. A simultaneous change of both temperatures proves not to be a mere linear superposition of both individual temperature dependences. We show that the generated waves are phase-coherent by calculating the fractional bandwidth.

Conclusions. Plasma streaming instabilities of the pulsar pair plasma can efficiently generate coherent radio signals if the streaming velocity is ultra-relativistic with Lorentz factors in the range 13 <  γ <  300, if the background and beam temperatures are small enough (inverse temperatures ρ0; ρ1 ≥ 1, i.e., T0; T1 ≤ 6 × 109), and if the beam-to-background plasma density ratio n1/(γbn0) exceeds 10−3, which means that n1/n0 has to be between 1.3 and 20% (depending on the streaming velocity).
Double detonations of sub-MCh CO white dwarfs: variations in Type Ia supernovae due to different core and He shell masses
Authors: Gronow Sabrina , Collins Christine E. , Sim Stuart A. , Röpke Friedrich K.
Published: March 2021

Sub-Chandrasekhar mass carbon-oxygen white dwarfs with a surface helium shell have been proposed as progenitors of Type Ia supernovae (SNe Ia). If true, the resulting thermonuclear explosions should be able to account for at least some of the range of SNe Ia observables. To study this, we conducted a parameter study based on three-dimensional simulations of double detonations in carbon-oxygen white dwarfs with a helium shell, assuming different core and shell masses. An admixture of carbon to the shell and solar metallicity are included in the models. The hydrodynamic simulations were carried out using the AREPO code. This allowed us to follow the helium shell detonation with high numerical resolution, and this improves the reliability of predicted nucleosynthetic shell detonation yields. The addition of carbon to the shell leads to a lower production of 56Ni, while including solar metallicity increases the production of intermediate mass elements. The production of higher mass elements is further shifted to stable isotopes at solar metallicity. Moreover, we find different core detonation ignition mechanisms depending on the core and shell mass configuration. This has an influence on the ejecta structure. We present the bolometric light curves predicted from our explosion simulations using the Monte Carlo radiative transfer code ARTIS and make comparisons with bolometric SNe Ia data. The bolometric light curves of our models show a range of brightnesses, which is able to account for subluminous to normal brightness SNe Ia. We show the model bolometric width-luminosity relation compared to data for a range of model viewing angles. We find that, on average, our brighter models lie within the observed data. The ejecta asymmetries produce a wide distribution of observables, which might account for outliers in the data. However, the models overestimate the extent of this compared to data. We also find that the bolometric decline rate over 40 days, Δm40(bol), appears systematically faster than data.
First direct measurement of auroral and equatorial jets in the stratosphere of Jupiter
Authors: Cavalié T. , Benmahi B. , Hue V. , Moreno R. , Lellouch E. , Fouchet T. , Hartogh P. , Rezac L. , Greathouse T. K. , Gladstone G. R. , Sinclair J. A. , Dobrijevic M. , Billebaud F. , Jarchow C.
Published: March 2021

Context. The tropospheric wind pattern in Jupiter consists of alternating prograde and retrograde zonal jets with typical velocities of up to 100 m s−1 around the equator. At much higher altitudes, in the ionosphere, strong auroral jets have been discovered with velocities of 1−2 km s−1. There is no such direct measurement in the stratosphere of the planet.

Aims. In this Letter, we bridge the altitude gap between these measurements by directly measuring the wind speeds in Jupiter’s stratosphere.

Methods. We use the Atacama Large Millimeter/submillimeter Array’s very high spectral and angular resolution imaging of the stratosphere of Jupiter to retrieve the wind speeds as a function of latitude by fitting the Doppler shifts induced by the winds on the spectral lines.

Results. We detect, for the first time, equatorial zonal jets that reside at 1 mbar, that is, above the altitudes where Jupiter’s quasi-quadrennial oscillation occurs. Most noticeably, we find 300−400 m s−1 nonzonal winds at 0.1 mbar over the polar regions underneath the main auroral ovals. They are in counterrotation and lie several hundred kilometers below the ionospheric auroral winds. We suspect them to be the lower tail of the ionospheric auroral winds.

Conclusions. We directly detect, for the first time, strong winds in Jupiter’s stratosphere. They are zonal at low-to-mid latitudes and nonzonal at polar latitudes. The wind system found at polar latitudes may help increase the efficiency of chemical complexification by confining the photochemical products in a region of large energetic electron precipitation.
Secular changes in length of day: Effect of the mass redistribution
Authors: Baenas T. , Escapa A. , Ferrándiz J. M.
Published: March 2021

In this paper the secular change in the length of day due to mass redistribution effects is revisited using the Hamiltonian formalism of the Earth rotation theories. The framework is a two-layer deformable Earth model including dissipative effects at the core–mantle boundary, which are described through a coupling torque formulated by means of generalized forces. The theoretical development leads to the introduction of an effective time-averaged polar inertia moment, which allows us to quantify the level of core–mantle coupling throughout the secular evolution of the Earth. Taking advantage of the canonical procedure, we obtain a closed analytical formula for the secular deceleration of the rotation rate, numerical evaluation of which is performed using frequency-dependent Love numbers corresponding to solid and oceanic tides. With this Earth modeling, under the widespread assumption of totally coupled core and mantle layers in the long term response, a secular angular acceleration of − 1328.6′′ cy−2is obtained, which is equivalent to an increase of 2.418 ms cy−1in the length of day. The ocean tides and the semidiurnal band of the mass-redistribution-perturbing potential, mostly induced by the Moon, constitute the main part of this deceleration. This estimate is shown to be in very good agreement with recent observational values, and with other theoretical predictions including comparable modeling features.
Finite stateN-agent and mean field control problems
Authors: Cecchin Alekos
Published: March 2021

We examine mean field control problems on a finite state space, in continuous time and over a finite time horizon. We characterize the value function of the mean field control problem as the unique viscosity solution of a Hamilton-Jacobi-Bellman equation in the simplex. In absence of any convexity assumption, we exploit this characterization to prove convergence, asNgrows, of the value functions of the centralizedN-agent optimal control problem to the limit mean field control problem value function, with a convergence rate of order [see formula in PDF]. Then, assuming convexity, we show that the limit value function is smooth and establish propagation of chaos,i.e.convergence of theN-agent optimal trajectories to the unique limiting optimal trajectory, with an explicit rate.
Convolution and deconvolution: two mathematical tools to help performing tests in research and industry
Authors: Fanton Jean-Pierre
Published: March 2021

The concepts of convolution and deconvolution are well known in the field of physical measurement. In particular, they are of interest in the field of metrology, since they can positively influence the performance of the measurement. Numerous mathematical models and computer developments dedicated to convolution and deconvolution have emerged, enabling a more efficient use of experimental data; this in sectors as different as biology, astronomy, manufacturing and energy industries. The subject finds today a new topicality because it has been made accessible to a large public for applications such as processing photographic images. The purpose of this paper is to take into account some recent evolutions such as the introduction of convolution methods in international test standards. Thus, its first part delivers a few reminders of some associated definitions. They concern linear systems properties, and integral transforms. If convolution, in most cases, does not create major calculation problems, deconvolution on the contrary is an inverse problem, and as such needs more attention. The principles of some of the methods available today are exposed. In the third part, illustrations are given on recent examples of applications, belonging to the domain of electrical energy networks and photographic enhancement.
Endoprothetik am oberen Sprunggelenk
Authors: Dohle Jörn , Stukenborg-Colsman Christina , Plaaß Christian
Published: March 2021

Meist ist die Arthrose des oberen Sprunggelenks (OSG) die Spätfolge einer Sprunggelenkfraktur. Bei fortgeschrittenen Arthrosen bleibt – nach Ausschöpfung der konservativen Therapieoptionen – an operativen Verfahren nur die Wahl zwischen OSG-Arthrodese und OSG-Prothese, deren Technik und Nachbehandlung der Artikel vorstellt. Die erreichte Beweglichkeit nach endoprothetischer Versorgung ist meist geringer als das physiologische Normalmaß, trotzdem funktionell meist ausreichend.
Rückenschmerz
Authors: Lassen Josephine , Gierthmühlen Janne , Baron Ralf
Published: March 2021

Rückenschmerz ist ein häufiges Krankheitsbild in der Gesellschaft und stellt die zweithäufigste Ursache für Berufsunfähigkeit in Deutschland dar. Vor allem akuter Rückenschmerz kann Anzeichen einer behandlungsbedürftigen Situation sein, wichtige Differenzialdiagnosen sollten abgeklärt werden. Häufig chronifizieren Rückenschmerzen im Verlauf. Die beschriebenen Symptome sind meist nicht eindeutig nozizeptiv oder neuropathisch, oft zeigt sich ein Mischbild beider Schmerzkomponenten. Dies spielt eine Rolle bei der Therapie, weshalb wegweisende Symptome erfragt werden sollten. Wichtige Schlüsselwörter, die einen neuropathischen Schmerz vermuten lassen, sind u. a. Brennschmerz und einschießender Schmerz sowie das Auftreten von Parästhesien wie Kribbeln und Ameisenlaufen. Die Schmerztherapie sollte leitliniengerecht erfolgen und aktivierende Maßnahmen beinhalten. Eine regelmäßige Bewertung von Verlauf und Therapie ist erforderlich.
Patientenspezifische Implantate in der Mund-, Kiefer- und Gesichtschirurgie
Authors: Eckstein Fabian Matthias , Zeller Alexander-Nicolai , Korn Philippe , Jehn Philipp , Spalthoff Simon , Tavassol Frank , Rahlf Björn , Gellrich Nils-Claudius
Published: March 2021

Die Verwendung von patientenspezifischen Implantaten zur Rekonstruktion von Defekten des Schädels und der Kiefer hat sich in den letzten Jahren als Standard in der Mund-, Kiefer- und Gesichtschirurgie etabliert. Anfänglich wurden die zum Einsatz kommenden Implantate intraoperativ direkt an die Defektsituation angepasst. Mit dem Fortschritt in der 3-dimensionalen Bildgebung und im Zuge der zunehmenden Digitalisierung wurden zunächst patientenspezifische 3-D-gedruckte Biomodelle zur direkten Anpassung konfektionierter Implantate im Operationssaal verwendet. Heute kommen vermehrt Implantate zum Einsatz, die im Rahmen eines computerassistierten Designprozesses (CAD) und einer anschließenden computerassistierten Herstellung (CAM) vollständig digital geplant werden. Anfangs war die Verwendung dieser CAD/CAM-gefertigten Implantate auf Defekte mit einfachen Geometrien, wie die Rekonstruktion des Schädeldachs, beschränkt. Durch Fortschritte in der digitalen Planung und der
digital gestützten Herstellung können CAD/CAM-gefertigte patientenspezifische Implantate heute auch zur Versorgung komplexer Defektsituationen im präventiven und funktionalisierten Design verwendet werden. Neben der Orbitarekonstruktion und der alloplastischen Rekonstruktion des Unterkiefers kommen individualisierte Implantate auch zur komplexen dentalen Rehabilitation und funktionellen Wiederherstellung der Kiefergelenke zum Einsatz.
Entwicklung der Notaufnahmefallzahlen eines Schwerpunktversorgers im Verlauf der Corona-Pandemie in Mecklenburg-Vorpommern
Authors: Stöwhas Mathias , Lippert Hans
Published: March 2021

Einleitung Als Reaktion auf die Corona-Pandemie fand im Frühjahr 2020 ein gesellschaftlicher Stillstand statt. Untersucht werden soll, wie diese Pandemie-Maßnahme auf die Bevölkerung eines ländlich geprägten, strukturschwachen Bundeslandes am Beispiel der Notaufnahmefallzahlen eines Schwerpunktversorgers gewirkt hat.

Methoden Abruf von anonymisierten aggregierten Routinedaten und Auswertung der Phasen „Vergleich“ (03.07.2019–15.03.2020), Corona–Phase 1“ (16.03.2020–06.05.2020) und „Corona–Phase 2“ (07.05.2020–31.07.2020).

Ergebnisse Auswertung von 24977 Patientendaten (2493 Patienten Corona-Phase 1/5106 Patienten Phase 2). 53% der Patienten sind älter als 50 Jahre, ca. 30% älter als 70 Jahre. Regulär suchen 67,6 Patienten die Notaufnahme je Tag auf. In der Corona-Phase 1 reduziert sich die Zahl um 19,7 Patienten/Tag; in der Phase 2 sind 8,2 Patienten/Tag weniger als in der Vergleichsgruppe – bei insgesamt unveränderter Altersstruktur. 56% der Patienten suchen eigenständig (Selbstvorstellung) die Notaufnahme auf, 24% auf Veranlassung eines Vertragsarztes, 17% werden durch den Rettungsdienst (Notarzt, RTW) vorgestellt. Besonders auffällig ist der Fallzahlrückgang bei den Patienten, die sich selbst in der Notaufnahme vorstellen und vom Kassenarzt eingewiesen werden. Die Fallzahlen über den Rettungsdienst (NEF, RTW) sind relativ stabil – bzw. in der 2. Corona-Phase anteigend (Notarzt+7%, RTW+36%). Das Hauptdiagnosespektrum der aus der Notaufnahme stationär aufgenommenen Patienten umfasst bei den Vertragsarzteinweisungen und Selbstvorsteller 375 bzw. 360 ICD-10-GM Dreistellergruppen. Hierbei reduzieren sich typische Notfallerkrankungen deutlich (Hirninfarkt (I63) -52%, Herzinfarkt (I21) -61%, Cholelithiasis (K80) −75% bei Selbstvorstellungen/Vorhofflimmern (I48) −55%, akute Bronchitis (J20) – 35%, Gastroenteritis (A09) −48% bei Vertragsarzteinweisungen – jeweils Corona-Phase 1 zu Vergleichsgruppe). Diese Fallzahlverluste sind überwiegend in der Corona-Phase 2 persistent (Hirninfarkt (I63) – 29% bei Selbstvorstellern) und nur z. T. reversibel (Herzinfarkt (I21)+10%).

Schlussfolgerung Eine Reduktion von Notfallkontakten, die nicht final durch den Pandemieverlauf erklärbar ist, v. a. der Selbstvorstellungen, Kassenarztvorstellungen fanden statt. Die Reduktion der Fallzahlen v. a. der überwiegend älteren Patienten, die selbstständig oder über den Kassenarzt vorgestellt wurden, überwog den Anteil des professionellen Rettungsdienstes deutlich. Es kann vermutet werden, dass Pandemie-Maßnahmen selbst zu diesem Effekt – trotz ausreichender medizinischer Ressourcen- geführt haben. „Infektionsangst“ als alleiniges Erklärungsmodell überzeugt nicht, da in Mecklenburg die Pandemie einen sehr milden, fallzahlschwachen Verlauf ohne Hotspot-Ereignisse in Krankenhäusern hatte. Untersuchungen zur Entscheidungsfindung der Bevölkerung bei Notfällen im weiteren Pandemieverlauf sind notwendig.
Family planning with inflammatory bowel disease: the challenge of childlessness and parent concerns
Authors: Walldorf Jens , Pijan Emilia , Greinert Robin , Riesner-Wehner Anica , Michl Patrick
Published: March 2021

Background In patients with inflammatory bowel disease (IBD), diagnosis is often established at the beginning of childbearing age. Accordingly, concerns about family planning and pregnancy (FPP) are common. Poor knowledge regarding FPP might contribute to increased childlessness in patients with IBD.

Methods The Crohn’s and Colitis Pregnancy Knowledge Score (CCPKnow, 17 multiple-choice questions) was translated into German and then used for a web-based survey. Childlessness was analyzed with respect to socio-demographic and disease-related information, and the knowledge (CCPKnow) and concerns of IBD patients with children were compared to those of voluntarily childless (VC) and non-voluntarily childless (NVC) IBD patients.

Results Childlessness was observed in 57.4 % of the 533 participants (90.6 % women, 63.0 % Crohn’s disease, 31.5 % ulcerative colitis, mean age 33.2 ± 8.6 years), voluntary childlessness in 9 %. The mean overall CCPKnow was adequate (9.38 ± 3.96). Poor knowledge was not associated with increased childlessness (CCPKnow of < 8 was found in 29.8 % of patients with children and 28.9 % of childless patients, p > 0.5). Instead, the patients’ education, medical advice, FPP-related concerns, impaired body image, and sexual dysfunction had a significant impact on childlessness. Frequent concerns included adverse effects of the patient’s medication on their child (36 % of the respondents), malformation (33 %), miscarriage (34.5 %), and the inheritability of IBD (57 %).

Conclusions Factual knowledge does not reduce disease-related concerns or childlessness. Correct but possibly bothersome information on FPP might contribute to childlessness in patients with IBD. Our findings underline the need for qualified counseling of IBD patients regarding FPP by an experienced IBD physician.
Selecting high velocity impact techniques
Authors: Patrick Chris
Published: March 2021

The range of available high velocity impact techniques, including laser-induced particle impact test, are suited for learning more about materials for a variety of applications.
An empirical nonlinear dynamics approach to analyzing emergent behavior of agent-based models
Authors: Medina Miles , Huffaker Ray , Muñoz-Carpena Rafael , Kiker Gregory
Published: March 2021

Agent-based models (ABMs) simulate the behavior of complex systems from bottom to top so that macro-scale patterns emerge from randomized micro-scale interactions among autonomous agents and their environment. However, our ability to construct complex ABMs currently exceeds our capacity to evaluate their emergent dynamics, contributing to an explainability problem in convincing policymakers that in silico experimentation with ABMs can be trusted to correspond to the real world they are charged with regulating. While there is no universally agreed-upon approach for analyzing or benchmarking ABM dynamics, past work has emphasized statistical and probabilistic analyses. Consistent with a key feature of ABMs—the macro-level order emerges from micro-level randomness—we propose a deterministic analytical framework built from nonlinear time series methods to reveal an emergent low-dimensional dynamical structure concealed in complex ABM output. In particular, embedding ABM dynamics (time series) in a nonlinear state space enables diagnosis of a low-dimensional structure, inference of causal interaction regimes among macro-level variables, extraction of a phenomenological meta-model consisting of a system of ordinary differential equations, and benchmarking of ABMs against real-world systems, to establish credibility in the eyes of policymakers and stakeholders. We demonstrate the deterministic approach with a canonical model for virus outbreaks.
Effects of magnetic fields related to submarine power cables on the behaviour of larval rainbow trout (
Authors: Jakubowska Magdalena , Greszkiewicz Martyna , Fey Dariusz P. , Otremba Zbigniew , Urban-Malinga Barbara , Andrulewicz Eugeniusz
Published: March 2021

The aim of this study was to determine the effects of artificial magnetic fields on the behaviour of rainbow trout (Oncorhynchus mykiss) larvae. Individuals (from the eyed egg stage) were exposed to a static magnetic field (SMF) of 10 mT or a low-frequency alternating (electromagnetic) field (EMF) of 1 mT, whereas larvae in the control treatment were reared under a natural geomagnetic field (GMF). After 40 days exposure, larvae were tested for 46 h for their attraction to or avoidance of magnetic fields. None of the groups of larvae avoided either the static or alternating field. By contrast, a mean of 54–60% of individuals was recorded in magnetic fields. Moreover, larvae exposed to SMF or EMF were more attracted to their respective magnetic field than individuals reared under a natural GMF. In addition, no stress response (i.e. a change in the oxygen consumption rate) was recorded for O. mykiss larvae exposed to magnetic fields. These results suggest, for the first time, that early life stages of rainbow trout can detect and are attracted to artificial magnetic fields of a magnitude recorded in the vicinity of submarine cables, with no visible signs of stress (i.e. increased oxygen consumption).
Altitudinal transects reveal large differences in intact lipid composition among soils
Authors: Warren Charles R.
Published: March 2021

Fatty acid-based lipids comprise a small but important component of soil organic matter. Lipids are indispensable components of soil microbes due to their function as components of membranes and as stores of energy and C. Hence, lipid composition is likely under strong selection pressure and there ought to be strong associations between lipid composition of microbial communities and environmental conditions. Associations between microbial lipids and environment likely involve an integrated combination of differences in lipid headgroups (classes) and fatty acyl chains. However, past studies examining associations between soil lipid composition and environmental conditions have focussed on fatty acids hydrolysed from polar lipids and less is known about headgroups (classes) of polar lipids. The aim of this study was to examine associations between environmental conditions changing with altitude and the intact polar and non-polar lipids of soil microbial communities. We used two altitudinal transects, both spanning from forest through to above the alpine treeline, but separated from one another by ~700 km. Liquid chromatography-mass spectrometry identified 174 intact lipids to the level of class and sum composition. Approximately half of the pool of fatty acid-based lipids was accounted for by two classes of non-polar lipids (diacylglycerol and triacylglycerols), while the other half was dominated by three classes of polar lipids (phosphatidylethanolamine, phosphatidylcholine and diacylglyceryl-N,N,N-trimethylhomoserine). There were large differences among sites in the relative amounts of lipid classes. For example, diacylglyceryl-N,N,N-trimethylhomoserine varied among sites from 5 to 41% of the polar lipid pool, phosphatidylcholine from 31 to 60% of the polar lipid pool, and diacylglycerols from 9 to 53% of the total non-polar pool. Relationships of lipid composition with altitude were weak or differed between transects, and pH was the variable most strongly associated with lipid composition. Variation among sites in the relative abundance of phosphatidylcholine were positively associated with pH, while relative and absolute abundance of diacylglycerol was negatively related to pH. We suggest that the accumulation of diacylglycerol at low pH represents slowed hydrolysis and/or microbial utilisation. A large fraction of variance among sites in lipid composition remained unexplained, which highlights the need for additional research on processes leading to production and consumption of fatty acid-based lipids.
Soil organic carbon and nitrogen in soil physical fractions in woody encroached grassland in South African savannas
Authors: Mureva Admore , Chivenge Pauline , Ward David
Published: March 2021

Woody plant encroachment has transformed land-cover patterns in savannas and grasslands throughout the world, with implications for changes in soil organic carbon (SOC) dynamics. However, our understanding of the effects of woody encroachment on SOC is very limited. In a study of pairs of neighbouring, woody encroached and grassland plots along a rainfall gradient (300–1500 mm mean annual precipitation, MAP) in South African savannas, we quantified the changes in SOC and nitrogen pools to a depth of 100 cm, in three soil physical fractions (coarse particulate organic matter, macroaggregates and silt and clay) and bulk soil. The 0–10 cm soil layer of the 1500 mm MAP site lost 26% of SOC stocks due to shrub encroachment. Contrastingly, the 300 and 350 mm MAP sites gained 24% and 27% total SOC, respectively, due to shrub encroachment. In the soil fractions, the largest changes in SOC, ranging within 2.64–464%, were in the coarse particulate organic matter (unprotected organic matter > 250 μm), and the lowest in the silt and clay fraction (6–32%) across all sites and depths. Soil nitrogen increased across all encroached sites compared with open grasslands, regardless of MAP. For every 1-unit increase in MAP and soil fraction size there was a change of –0.06 and 0.1 SOC (gC/kg soil) in encroached grasslands, respectively. We conclude that shrub-encroached grasslands potentially sequester more C in soils of arid regions than in humid regions. At three of our sites, we were unable to differentiate SOC between encroached and open-grassland soils from bulk soil but could do so from soil fraction analysis. Thus, soil fraction analysis is a more effective way to assess changes in soil C than bulk soil.
The politics of incontournables: entrenching patronage networks in eastern Congo’s mineral markets
Authors: Vogel Christoph
Published: March 2021

Years after the formal end of two devastating wars, the Congo’s eastern Kivu provinces meander in a limbo of contested politics, deep-seated insecurity and armed mobilisation. Through the prism of the artisanal mining sector, which is currently undergoing significant regulatory transformation, this article studies the convoluted networks of political and economic order that underpin (in)security. Investigating the links between violence, reform and patronage, it asks how powerbrokers adapt to changing logics of conflict and resource extraction amid transnational reform that aims at ‘conflict-free’ mineral sourcing. Revisiting the notion of patronage, the article argues that political and economic order are socio-spatially entwined and demonstrates how a certain type of stakeholder – known collectively as incontournables – commands multiple loyalties across entangled networks of mineral exploitation and trade that extend far into the political, economic and military spheres of authority.
Upper limb movement profiles during spontaneous motion in acute stroke
Authors: Datta Shreyasi , Karmakar Chandan K , Rao Aravinda S , Yan Bernard , Palaniswami Marimuthu
Published: March 2021

Objective.The clinical assessment of upper limb hemiparesis in acute stroke involves repeated manual examination of hand movements during instructed tasks. This process is labour-intensive and prone to human error as well as being strenuous for the patient. Wearable motion sensors can automate the process by measuring characteristics of hand activity. Existing work in this direction either uses multiple sensors or complex instructed movements, or analyzes only thequantityof upper limb motion. These methods are obtrusive and strenuous for acute stroke patients and are also sensitive to noise. In this work, we propose to use only two wrist-worn accelerometer sensors to study thequalityof completely spontaneous upper limb motion and investigate correlation with clinical scores for acute stroke care.Approach.The velocity time series estimated from acquired acceleration data during spontaneous motion is decomposed into smaller movement elements. Measures of density, duration and smoothness of these component elements are extracted and their disparity is studied across the two hands.Main results.Spontaneous upper limb motion in acute stroke can be decomposed into movement elements that resemble point-to-point reaching tasks. These elements are smoother and sparser in the normal hand than in the hemiparetic hand, and the amount of smoothness correlates with hemiparetic severity. Features characterizing the disparity of these movement elements between the two hands show statistical significance in differentiating mild-to-moderate and severe hemiparesis. Using data from 67 acute stroke patients, the proposed method can classify the two levels of hemiparetic severity with 85% accuracy. Additionally, compared to activity-based features, the proposed method is robust to the presence of noise in acquired data.Significance.This work demonstrates that the quality of upper limb motion can characterize and identify hemiparesis in stroke survivors. This is clinically significant towards the continuous automated assessment of hemiparesis in acute stroke using minimally intrusive wearable sensors.
High voltage carrier stored trench bipolar transistor with common anode polysilicon diodes gate structure for low Miller capacitance and low electromagnetic interference noise
Authors: Zhao Yishang , Li Zehong , Hu Wenjin , Yang Yang , Zeng Xiao , Li Luping , Guo Qiao , Yuan Qiang , Ren Min , Zhang Bo
Published: March 2021

A novel 3300 V high voltage carrier stored trench bipolar transistor (CSTBT) with common anode polysilicon diodes gate structure (CAPD-CSTBT) is proposed. The PN junctions and N+ emitter region in the polysilicon gate structure are beneficial for reducing the Miller capacitance by 88.1% and the input capacitance by 26.0%, while due to the polysilicon PN junction barrier, the forward and reverse gate bias voltage will not be affected. As a result, the transient energy loss could be decreased by 32.2% with the same range of R
g. Since the displacement current is shielded by the embedded emitter on the bottom of the CAPD gate structure, the (dI
CE
/dt)max/I
Load is lower than that of the Fin-P-CSTBT by 81.8% on average with the same range of turn-on energy loss. Furthermore, the proposed structure features a 58.7% lower (dV
KA
/dt)max/V
cc value for the free-wheeling diode on average. By Fourier transformation, the proposed structure represents lower amplitudes for the I
CE and V
KA spectrums during the turn-on period, which is a drastic suppression of electromagnetic interference noise.
Galaxy imaging surveys as spin-sensitive detector for cosmological colliders
Authors: Kogai Kazuhiro , Akitsu Kazuyuki , Schmidt Fabian , Urakawa Yuko
Published: March 2021

Galaxy imaging surveys provide us with information on both
the galaxy distribution and their shapes. In this paper, we
systematically investigate the sensitivity of galaxy shapes to new
physics in the initial conditions. For this purpose, we decompose
the galaxy shape function into spin components, and compute the
contributions to each spin component from both intrinsic alignment
and weak lensing. We then consider the angular-dependent primordial
non-Gaussianity, which is generated by a non-zero integer spin
particle when active during inflation, and show that a galaxy
imaging survey essentially functions as a spin-sensitive detector of
such particles in the early universe. We also perform a forecast of
the PNG generated from a higher spin particle, considering a Rubin
Observatory LSST-like galaxy survey.
Science Commissioning of NIHTS: The Near-infrared High Throughput Spectrograph on the Lowell Discovery Telescope
Authors: Gustafsson Annika , Moskovitz Nicholas , Cushing Michael C. , Bida Thomas A. , Dunham Edward W. , Roe Henry
Published: March 2021

The Near-Infrared High Throughput Spectrograph (NIHTS) is in operation on the 4.3 m Lowell Discovery Telescope (LDT) in Happy Jack, AZ. NIHTS is a low-resolution spectrograph (R ∼ 200) that operates from 0.86 to 2.45 microns. NIHTS is fed by a custom dichroic mirror which reflects near-infrared wavelengths to the spectrograph and transmits the visible to enable simultaneous imaging with the Large Monolithic Imager (LMI), an independent visible wavelength camera. The combination of premier tracking and acquisition capabilities of the LDT, a several arcminutes field of view on LMI, and high spectral throughput on NIHTS enables novel studies of a number of astrophysical and planetary objects including Kuiper Belt Objects, asteroids, comets, low mass stars, and exoplanet hosts stars. We present a summary of NIHTS operations, commissioning, data reduction procedures with two approaches for the correction of telluric absorption features, and an overview of select science cases that will be pursued by Lowell Observatory, Northern Arizona University, and LDT partners.
PyLightcurve-torch: a transit modeling package for deep learning applications in PyTorch
Authors: Morvan Mario , Tsiaras Angelos , Nikolaou Nikolaos , Waldmann Ingo P.
Published: March 2021

We present a new open source python package, based on PyLightcurve and PyTorch Paszke et al., tailored for efficient computation and automatic differentiation of exoplanetary transits. The classes and functions implemented are fully vectorised, natively GPU-compatible and differentiable with respect to the stellar and planetary parameters. This makes PyLightcurve-torch suitable for traditional forward computation of transits, but also extends the range of possible applications with inference and optimization algorithms requiring access to the gradients of the physical model. This endeavour is aimed at fostering the use of deep learning in exoplanets research, motivated by an ever increasing amount of stellar light curves data and various incentives for the improvement of detection and characterization techniques.
Distribution identification and information loss in a measurement uncertainty network
Authors: Duncan Paul M , Whittaker D S
Published: March 2021

Measurement uncertainty is an increasingly important consideration in many applications demanding extreme performance levels. In the era of the internet of things and 5G connectivity we can learn more about device performance by utilising the increasing amount of data produced. These data require appropriate information infrastructure to facilitate continuous updating of device performance knowledge. This paper presents the results of a study which NPL undertook with a leading test and measurement device manufacturer to examine how measurement uncertainty propagates through the data traceability chain from national standards to end devices. A hierarchy of siloed calculations and heuristics did not enable a satisfactory metadata exchange within the dataflow to ensure an internally consistent calculation of measurement uncertainty. We therefore propose a novel measurement uncertainty network which contains a set of internally consistent measurement models, traceable to national standards and connected through common quantities. The network facilitates sharing and programmatic processing of measurement data with due regard to timeliness, privacy preservation and adherence to FAIR principles in measurement data exchange. An illustrative example of this network is presented with techniques to determine the best-fitting standard probability distribution for a given dataset and the resulting change in information content.
On the relationship microstructure/properties on yield strength of a Fe-C-Mn steel
Authors: Aburto-Perdomo E , Duran-Nuñez A , Ramirez-Ledesma A L , Juarez-Islas J A
Published: March 2021

Fe-C-Mn steel was produced by the electric arc furnace, vacuum degassing, ladle treatment and continuous casting route followed by a hot rolling schedule, water quench and tempered. Then, after evaluation of the microstructure and mechanical properties of the steel, a relationship between microstructure and mechanical properties was presented focusing on the impact of the different strengthening mechanisms on the resulting yield strength.
The inverse problem of a dynamical system solved with genetic algorithms
Authors: Esquivel Ricardo Medel , Gómez-Vargas Isidro , Montalvo Teodoro Rivera , Vázquez J. Alberto , García-Salcedo Ricardo
Published: March 2021

In this work, we propose a complete methodology to identify the parameters of a dynamical system from a data set using genetic algorithms. Considering the search for the model parameters as an inverse problem, we numerically solve the differential equations of the dynamical system; each set of parameters is then considered as an individual of the population that evolves in the genetic algorithm. As a fitness function we use the distance L1 between the numerical solution and the data.
Modeling of meteorological variables in localities without meteorological data, from the data recorded in neighboring locations that have topomesoclimatically similar conditions for the installation of renewable energy projects
Authors: Mera E , Pacheco P , Parodi C , Gutiérrez L
Published: March 2021

The present study models meteorological variables for a sector with nonexistent data through the technique of data imputation [2,3] for the installation of renewable energy projects, which in a first step seek for data generated under similar conditions, and in a second step applies a ratio [2] to these data based on an expert consultation. To validate the methodology, a meteorological station representative of the sector under study was installed and the modeled and real values were contrasted, registering that the lowest correlation coefficient is in the variable of Wind Speed (0.246) and high in the variable Temperature (0.657).
A mathematical model for solar cookstoves: the relation between thermal and optical parameters
Authors: Servín H , González-Avilés M , Sobral H , Peña-Gomar M
Published: March 2021

The article presents a mathematical model that relates the thermal properties of a concentration solar cooker with some optical properties of several of the materials used in its elaboration. Solar cookers are studied from the point of view of its functionality through their thermal performance, in terms of calculating the standard cooking power and thermal efficiency with field tests. Some of the materials characteristics that are important to make concentrating solar stoves are: the reflectance of the surface of the concentrator, the transmittance of the cover and the absorbance of the surface of the food container. Through an analysis of heat transfer, it is built a model for calculating thermal parameters depending on the optical parameters. A comparison of the model is made by varying the absorbance and reflectance of the coating that covers the food container. The results of the model agree with those found experimentally.
Optical Characterization of Biomass Soot Samples
Authors: Peña-Gomar M , Sobral H , Servin Campuzano H , González-Avilés M
Published: March 2021

Soot from different biomass sources is investigated to develop absorbent coatings for use in solar cookers. Soot samples were analysed by spectral and solar reflectance in the range 280-2400 nm, by its organic elemental composition and through Raman spectroscopy. The soot was obtained from biomass burning of sugarcane, pine resin and firewood in a hearth. The averaged spectral reflectance for sugarcane soot is 3.5%, for wood-stove soot is 2.7% and the lower value corresponds to pine resin soot at 1.4%. Likewise, the lowest value of the solar reflectance was of 14.8 Wm−2 for pine resin soot. In addition, elemental composition analysis showed that pine resin also has the highest carbon content. Raman spectroscopy measurements were performed to find the structure and the degree of disorder in the graphite structure.
3-D printing of crystal and polycrystal physical properties
Authors: Batista-Fierro B , Duarte-Ortiz C A , Villalobos-Portillo E E , Fuentes-Cobas L E
Published: March 2021

The article contains a compact summary of cause-effect relationships regarding the structure-properties link in crystals and polycrystals. Neumann’s principle is addressed and visualized in tensor and longitudinal surface treatments. Properties databases and representation algorithms are presented. A software package for 3D printing of physical properties’ surfaces, as a helpful tool for anisotropy visualization, has been created. The required parameters and equipment are disclosed. The article includes examples of experimental data obtained from the MPOD database and several practical illustrations.
N-AcetylLaspartic Acid Phantom for Proton Magnetic Resonance Spectroscopy at 1.5 T and 3 T
Authors: Martin R , Marrufo O , Solis-Najera S , Rodriguez A O , Vazquez F
Published: March 2021

Proton Magnetic Resonance Spectroscopy (MRS) phantoms are an important tool for quality assurance and reliability. Some of the contents are not easily available in some countries due to some company policies. We built a phantom using N-Acetyl-DL-aspartic acid as a substitute for N-Acetyl-L-aspartic acid for proton magnetic resonance spectroscopy of human brain at 1.5 T and 3 T. To quantify the B0 homogeneity, phase and magnitude images of a commercial phantom were also acquired with a standard gradient echo sequence. Spectra obtained were corrected and dismissed critical chemical shift due to inhomogeneities. Spectra numerical simulations at 1.5 T and 3 T were performed using a free jMRUI and point resolved spectroscopy sequence for various times of echo. In vitro single-voxel spectra were obtained with the phantom prototype and a commercial phantom using the substitute acid and the same pulse sequence and magnetic field magnitudes as before. Simulated and in vitro spectra showed a very good concordance and majority of metabolites were readily identified for both fields. Spectra acquired with the phantom prototype complied with those quality control criteria for clinical use for both field strengths. This approach offers an alternative way to conduct clinical magnetic resonance spectroscopy.
Gas measurement system for Bio-hydrogen production based on nejayote’s dark phase fermentation
Authors: Tavera-Romero F , Ríos-Maravilla A , Granados-Samaniego J , Turpin S
Published: March 2021

Nejayote is the residual water from the corn nixtamalization process, this is considered a pollutant when it is discharged into the public sewer system due to its high demand for oxygen, high temperature, and pH. There is Biohydrogen production with the use of dark-phase fermentation of nejayote in the presence of clostridius. To determine the concentrations of the different gases produced H2, CH4, CO2, was designed and build a data acquisition system on Lab View development platform, using MQ-X type sensors and Arduino UNO prototyping board. Was adapted an airtight plastic container with capacity of 30 ml with special nozzles to allow multiple needle entries and injections of different samples. This device allows us to quantify the biohydrogen obtained from the various concentrations used in the reactors to obtain the optimal mixture.
Index development with the keyword in context method in the online library catalog
Authors: Safii M , Martutik  , Harsiati T , Kurniawan T , Asari A , Rahmania L A , Prasetyawan A , Arraja Y G
Published: March 2021

Academic libraries have an essential role in the academic community. As a reference center, libraries provide access to online reference sources or book collections. One of the facilities provided is the library automation which facilitate users to access library resources. With an online catalog that is easy to operate, it will be easier for users to get information. However, libraries generally only provide interface search facilities which make it difficult for users to find information. This study aims to produce an index on the online library catalog using the KWIC (KeyWord in Context) method. The data was collected from the Open Archive Initiative Protocol for Metadata Harvesting (OAI-PMH) on the Library server. In the data harvesting process, around 50,000 data were found to be processed. The finding in this study indicates that the library’s online catalog metadata index makes it easier for users to retrieve information.
The design of learning media using JavaScript and its implementation in the local web server
Authors: Laini S , Kalam A N , Anjelina S , Alfat S
Published: March 2021

The ranking of Indonesian science competencies at the global level in 2018 was in the 70th of 78 countries. The low student learning activities is one of the trigger factors. One impacts the use of learning media which is not appropriate, such as decreased learning motivation which ultimately impacts the low student learning activities. This research intends to design learning media based on offline using JavaScript programming language and combined in a local network system. The method used is Research and Development. The specifications of the tools and materials used are MAC Mini Intel Core I7 Quad-Core 3.6 GHz, 16 GB DDR4 memory, and SATA 2 TB HDD. The use of learning media is expected to overcome several problems in conventional learning and become one of the solutions to distance learning systems.
The development of the implementation of discovery learning and the influence to the student’s conjecturing ability to solve local irregularity vertex coloring in graphs
Authors: Nikmah N , Kristiana A I , Dafik  , Hobri  , Slamin
Published: March 2021

This research aims to explain about development of the implementation of discovery learning and the influence of student’s conjecturing ability to solve local irregularity vertex coloring in graphs. Discovery learning is one of the learning model that can be used to improve the ability of students to conjecture in solving mathematical problems. For processing of data their conjecturing ability using a triangulation methods, namely a combination of qualitative and quantitative methods. Students majoring in Mathematics Education at Jember University are research subjects. Subjects of this research using experimental class and control class. Different treatments are offered to both class. This research results findings indicate that there is a major gap between both class implementing discovery learning and teacher centered learning.