bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactions between large-scale radio structures and gas in a sample of optically selected type 2 quasars
Authors: Villar Martín M. , Emonts B. H. C. , Cabrera Lavers A. , Bellocchi E. , Alonso Herrero A. , Humphrey A. , Dall’Agnol de Oliveira B. , Storchi-Bergmann T.
Published: March 2021

Context. The role of radio mode feedback in non radio-loud quasars needs to be explored in depth to determine its true importance. Its effects can be identified based on the evidence of interactions between the radio structures and the ambient ionised gas.

Aims. We investigate this interaction in a sample of 13 optically selected type 2 quasars (QSO2) at z < 0.2 with the Very Large Array (VLA) FIRST Survey radio detections, none of which are radio-loud. The ranges of [OIII]λ5007 and monochromatic radio luminosities are log(L[OIII]/erg s−1) ∼ 42.08–42.79 and log(P1.4 GHz/erg s−1 Hz−1) ∼ 30.08−31.76. All of them show complex optical morphologies, with signs of distortion across tens of kpc due to mergers and interactions.

Methods. We searched for evidence of interactions between the radio structures and the ionised gas by characterising and comparing their morphologies. The former was traced by narrow band Hα images obtained with the GTC 10.4 m Spanish telescope and the Osiris instrument. The latter is traced by VLA radio maps obtained with A and B configurations to achieve both high resolution and brightness sensitivity.

Results. The radio luminosity has an active galatic nucleus (AGN) component in 11 our of 13 QSO2, which is spatially extended in our radio data in 9 of them (jets, lobes, or other). The relative contribution of the extended radio emission to the total P1.4 GHz is in most cases in the range from 30% to 90%. The maximum sizes are in the range of dRmax of around a few to 500 kpc. The QSO2 undergoing interaction or merger events appear to be invariably associated with ionised gas spread over large spatial scales with maximum distances from the AGN in the range rmax ∼ 12−90 kpc. The morphology of the ionised gas at < 30 kpc is strongly influenced by AGN related processes. Evidence for radio-gas interactions exist in 10 out of 13 QSO2; that is, in all but one with confirmed AGN radio components. The interactions are identified across different spatial scales, from the nuclear narrow line region up to tens of kpc.

Conclusions. Although this sample cannot be considered representative of the general population of QSO2, it supports the idea that large-scale low to modest power radio sources can exist in radio-quiet QSO2, which can provide a source of feedback on scales of the spheroidal component of galaxies and well into the circumgalactic medium, in systems where radiative mode feedback is expected to dominate.
Millimeter- and submillimeter-wave spectrum of trans-formaldoxime (CH2NOH)
Authors: Zou Luyao , Guillemin Jean-Claude , Motiyenko Roman A. , Margulès Laurent
Published: March 2021

Context. Among the six atoms of N-containing molecules with the formula of CH3NO, only formamide (H2NCHO), the most stable structural isomer, has been detected in the interstellar medium (ISM). The formaldoxime isomer may be formed, for example, by the reaction of formaldehyde (H2CO) or methanimine (H2CNH) and hydroxylamine (H2NOH), which are all detected in the ISM. The lack of high accuracy millimeter- and submillimeter-wave measurements hinders the astronomical search for formaldoxime.

Aims. The aim of this work is to provide the direct laboratory measurement of the millimeter- and submillimeter-wave spectrum of trans-formaldoxime.

Methods. Formaldoxime was synthesized and its rotational spectrum was recorded at room temperature in a glass flow cell using the millimeter- and submillimeter-wave spectrometer in Lille. The SPFIT program in the CALPGM suite was used to fit the spectrum.

Results. Rotational lines of trans-formaldoxime from both the ground state and v12 = 1 vibrational excited states have been measured and assigned from 150 to 660 GHz. Spectroscopic constants were derived to the tenth order using both Watson’s A and S reduction Hamiltonian.
Calibration of residual aberrations in exoplanet imagers with large numbers of degrees of freedom
Authors: Pourcelot R. , Vigan A. , Dohlen K. , Rouzé B. , Sauvage J.-F. , El Morsy M. , Lopez M. , N’Diaye M. , Caillat A. , Choquet E. , Otten G. P. P. L. , Abbinanti A. , Balard P. , Carbillet M. , Blanchard P. , Hulin J. , Robert É.
Published: March 2021

Imaging faint objects, such as exoplanets or disks, around nearby stars is extremely challenging because host star images are dominated by the telescope diffraction pattern. Using a coronagraph is an efficient solution for removing diffraction but requires an incoming wavefront with good quality to maximize starlight rejection. On the ground, the most advanced exoplanet imagers use extreme adaptive optics (ExAO) systems that are based on a deformable mirror (DM) with a large number of actuators to efficiently compensate for high-order aberrations and provide diffraction-limited images. While several exoplanet imagers with DMs using ∼1500 actuators are now routinely operating on large telescopes to observe gas giant planets, future systems may require a tenfold increase in the number of degrees of freedom to look for rocky planets. In this paper, we explore wavefront correction with a secondary adaptive optics system that controls a very large number of degrees of freedom that are not corrected by the primary ExAO system. Using Marseille Imaging Testbed for High Contrast (MITHiC), we implement a second stage of adaptive optics with ZELDA, a Zernike wavefront sensor, and a spatial light modulator to compensate for the phase aberrations of the bench downstream residual aberrations from adaptive optics. We demonstrate that their correction up to 137 cycles per pupil with nanometric accuracy is possible, provided there is a simple distortion calibration of the pupil and a moderate wavefront low-pass filtering. We also use ZELDA for a fast compensation of ExAO residuals, showing its promising implementation as a second-stage correction for the observation of rocky planets around nearby stars. Finally, we present images with a classical Lyot coronagraph on MITHiC and validate our ability to reach its theoretical performance with our calibration.
Self-preserving ice layers on CO2 clathrate particles: Implications for Enceladus, Pluto, and similar ocean worlds
Authors: Boström Mathias , Esteso Victoria , Fiedler Johannes , Brevik Iver , Buhmann Stefan Yoshi , Persson Clas , Carretero-Palacios Sol , Parsons Drew F. , Corkery Robert W.
Published: March 2021

Context. Gas hydrates can be stabilised outside their window of thermodynamic stability by the formation of an ice layer – a phenomenon termed self-preservation. This can lead to a positive buoyancy for clathrate particles containing CO2 that would otherwise sink in the oceans of Enceladus, Pluto, and similar oceanic worlds.

Aims. Here we investigate the implications of Lifshitz forces and low occupancy surface regions on type I clathrate structures for their self-preservation through ice layer formation, presenting a plausible model based on multi-layer interactions through dispersion forces.

Methods. We used optical data and theoretical models for the dielectric response for water, ice, and gas hydrates with a different occupancy. Taking this together with the thermodynamic Lifshitz free energy, we modelled the energy minima essential for the formation of ice layers at the interface between gas hydrate and liquid water.

Results. We predict the growth of an ice layer between 0.01 and 0.2 μm thick on CO, CH4, and CO2 hydrate surfaces, depending on the presence of surface regions depleted in gas molecules. Effective hydrate particle density is estimated, delimiting a range of particle size and compositions that would be buoyant in different oceans. Over geological time, the deposition of floating hydrate particles could result in the accumulation of kilometre-thick gas hydrate layers above liquid water reservoirs and below the water ice crusts of their respective ocean worlds. On Enceladus, the destabilisation of near-surface hydrate deposits could lead to increased gas pressures that both drive plumes and entrain stabilised hydrate particles. Furthermore, on ocean worlds, such as Enceladus and particularly Pluto, the accumulation of thick CO2 or mixed gas hydrate deposits could insulate its ocean against freezing. In preventing freezing of liquid water reservoirs in ocean worlds, the presence of CO2-containing hydrate layers could enhance the habitability of ocean worlds in our Solar System and on the exoplanets and exomoons beyond.
Spectral unmixing for exoplanet direct detection in hyperspectral data
Authors: Rameau J. , Chanussot J. , Carlotti A. , Bonnefoy M. , Delorme P.
Published: March 2021

Context. The direct detection of faint exoplanets with high-contrast instruments can be boosted by combining it with high spectral resolution. For integral field spectrographs yielding hyperspectral data, this means that the majority of the field of view consists of diffracted starlight spectra and a spatially localized planet. Observation analysis usually relies on classic cross-correlation with theoretical spectra, maximized at the position and with the properties of the planet. In a purely blind-search context, this supervised strategy can be biased with model mismatch and/or be computationally inefficient.

Aims. Using an approach that is inspired by the analysis of hyperspectral data within the remote-sensing community, we aim to propose an alternative to cross-correlation that is fully data-driven, which decomposes the data into a set of individual spectra and their corresponding spatial distributions. This strategy is called spectral unmixing.

Methods. We used an orthogonal subspace projection to identify the most distinct spectra in the field of view. Their spatial distribution maps were then obtained by inverting the data. These spectra were then used to break the original hyperspectral images into their corresponding spatial distribution maps via non-negative least squares. A matched filter with the instrument point-spread function (or visual inspection) was then used to detect the planet on one of the maps. The performance of our method was evaluated and compared with a cross-correlation using simulated hyperspectral data with medium resolution from the ELT/HARMONI integral field spectrograph.

Results. We show that spectral unmixing effectively leads to a planet detection solely based on spectral dissimilarities at significantly reduced computational cost. The extracted spectrum holds significant signatures of the planet while being not perfectly separated from residual starlight. The sensitivity of the supervised cross-correlation is three to four times higher than with unsupervised spectral unmixing, the gap is biased toward the former because the injected and correlated spectrum match perfectly. The algorithm was furthermore vetted on real data obtained with VLT/SINFONI of the β Pictoris system. This led to the detection of β Pictoris b with a signal-to-noise ratio of 28.5.

Conclusions. Spectral unmixing is a viable alternative strategy to a cross-correlation to search for and characterize exoplanets in hyperspectral data in a purely data-driven approach. The advent of large data from the forthcoming IFS on board JWST and future ELTs motivates further algorithm development along this path.
Observations of 12.2 GHz methanol masers towards northern high-mass protostellar objects
Authors: Durjasz M. , Szymczak M. , Wolak P. , Bartkiewicz A.
Published: March 2021

Context.Class II methanol masers at 6.7 and 12.2 GHz occur close to high-mass young stellar objects (HMYSOs). When they are observed simultaneously, such studies may contribute to refining the characterisation of local physical conditions.

Aims.We aim to search for the 12.2 GHz methanol emission in 6.7 GHz methanol masers that might have gone undetected in previous surveys of northern sky HMYSOs, mainly due to their variability. Contemporaneous observations of both transitions are used to refine the flux density ratio and examine the physical parameters.

Methods.We observed a sample of 153 sites of 6.7 GHz methanol maser emission in the 12.2 GHz methanol line with the Torun 32 m radio telescope, using the newly builtX-band receiver.

Results.The 12.2 GHz methanol maser emission was detected in 36 HMYSOs, with 4 of them detected for the first time. The 6.7–12.2 GHz flux density ratio for spectral features of the contemporaneously observed sources has a median value of 5.1, which is in agreement with earlier reports. The ratio differs significantly among the sources and for the periodic source G107.298+5.639 specifically, the ratio is weakly recurrent from cycle to cycle, but it generally reaches a minimum around the flare peak. This is consistent with the stochastic maser process, where small variations in the physical parameters along the maser path can significantly affect the ratio. A comparison of our data with historical results (from about ten years ago) implies significant (>50%) variability for about 47 and 14% at 12.2 and 6.7 GHz, respectively. This difference can be explained via the standard model of methanol masers.
Close encounters with the Death Star: Interactions between collapsed bodies and the Solar System
Authors: Pavlík Václav , Shore Steven N.
Published: March 2021

Aims. We aim to investigate the consequences of a fast massive stellar remnant – a black hole (BH) or a neutron star (NS) – encountering a planetary system.

Methods. We modelled a close encounter between the actual Solar System (SS) and a 2 M⊙ NS and a 10 M⊙ BH, using a few-body symplectic integrator. We used a range of impact parameters, orbital phases at the start of the simulation derived from the current SS orbital parameters, encounter velocities, and incidence angles relative to the plane of the SS.

Results. We give the distribution of possible outcomes, such as when the SS remains bound, when it suffers a partial or complete disruption, and in which cases the intruder is able to capture one or more planets, yielding planetary systems around a BH or a NS. We also show examples of the long-term stability of the captured planetary systems.
A new distant giant radio galaxy in the Boötes field serendipitously detected by Chandra
Authors: Masini Alberto , Celotti Annalisa , Grandi Paola , Moravec Emily , Williams Wendy L.
Published: March 2021

Context. Giant radio galaxies (GRGs) are the largest single structures in the Universe. Exhibiting extended radio morphology, their projected sizes range from 0.7 Mpc up to 4.9 Mpc. LOFAR has opened a new window on the discovery and investigation of GRGs and, despite the hundreds that are known today, their main growth catalyst is still under debate.

Aims. One natural explanation for the exceptional size of GRGs is their old age. In this context, hard X-ray selected GRGs show evidence of restarting activity, with the giant radio lobes being mostly disconnected from the nuclear source, if any are present at all. In this paper, we present the serendipitous discovery of a distant (z = 0.629), medium X-ray-selected GRG in the Boötes field.

Methods. High-quality, deep Chandra and LOFAR data allow for a robust study of the connection between the nucleus and the lobes, at a larger redshift, which has thus far been inaccessible to coded-mask hard X-ray instruments.

Results. The radio morphology of the GRG presented in this work does not show evidence for restarted activity and the nuclear radio core spectrum does not appear to be gigahertz-peaked spectrum (GPS)-like. On the other hand, the X-ray properties of the new GRG are perfectly consistent with the ones previously studied with Swift/BAT and INTEGRAL at lower redshift. In particular, the bolometric luminosity measured from the X-ray spectrum is a factor of six larger than the one derived from the radio lobes, although the large uncertainties make them formally consistent at 1σ. Finally, the moderately dense environment around the GRG, traced by the spatial distribution of galaxies, supports recent findings that the growth of GRGs is not primarily driven by underdense environments.
Assessment of downward draught in high-glazing facades in cold climates – experimental and CFD study into draught control with a 21-type radiator
Authors: Võsa Karl-Villem , Ferrantelli Andrea , Kurnitski Jarek
Published: March 2021

This paper investigates the interaction of a radiator’s thermal plume and downdraught of cold glazed surfaces. Draughts in working areas are one of the most common thermal comfort complaints in modern buildings. A typical solution for dealing with these draughts is positioning the heat emitters such as radiators or convectors under the windows. However, with thermally efficient envelopes, the internal loads compromise a relatively high fraction of the heating demand and the emitters are working under partial loads in modern buildings. This study comprises two parts: an experimental phase in the EN442 standardized test chamber with a 21-type radiator, and a CFD simulation phase, where the model is validated and applied under an expanded set of boundary conditions. The expanded simulation set results provide preliminary insight into sizing and design. More specifically, the thermal plume can be parametrised with a velocity and temperature value along with the room air and glazing temperatures for a broader analysis and assessment of the risk of draught.
Production of thermal energy in University building greenhouses in cold climate conditions
Authors: Conceição Eusébio , Gomes João , Lúcio Maria Manuela , Awbi Hazim
Published: March 2021

The present work focuses on the production of thermal energy in University building greenhouses in cold climate conditions. The building model uses a system of energy and mass balance integral equations, which are solved by the Runge–Kutta–Felberg method with error control. This numerical study is about the thermal behaviour of a university building with complex topology, in winter and transient conditions. The thermal comfort of the occupants, using the Predicted Mean Vote index, and the indoor air quality, using the carbon dioxide concentration, are evaluated. This building has 319 compartments distributed by four floors and it is equipped with one internal greenhouse in the third floor. This greenhouse is located on the south facing facade and the heated air in this space will be transported to compartments located on the north facing façade. The spaces subject to the influence of the heated air coming from the greenhouse improve the level of thermal comfort of its occupants. The level of indoor air quality in occupied spaces is acceptable according to international standards.
Measured performance of exhaust air heat pumps in Finnish apartment buildings
Authors: Pylsy Petri , Kurnitski Jarek
Published: March 2021

The energy efficiency of existing apartment buildings is playing an important role in energy and climate targets. In Finland, mechanical exhaust ventilation system is commonly used in older apartment buildings. Hence, there could be an energy saving potential by an exhaust air heat pump system (EAHP). In this work two cases have been studied. Buildings were built in 1960’s and 1970’s and in renovation equipped with hybrid heating system: district heating and exhaust air heat pump system. Two years measurement data, 2018 and 2019, was collected to evaluate the performance of exhaust air heat pump systems. According to measurement data the monthly coefficient of performance (COP) was calculated as well as seasonal coefficient of performance (SCOP) was defined. The monthly COP values varied from 3,1 to 4,6 and SCOP values were about 3,7. Heating energy cost savings were 23-31 %. Energy performance class before and after EAHP installation was calculated. If at least 50 % of heating energy consumption was covered by EAHP then also energy performance class was improved.
DHW tank sizing considering dynamic energy prices
Authors: Nord Natasa , Ding Yuemin , Ivanko Dmytro , Walnum Harald Taxt
Published: March 2021

Due to the rapid development of the building stock in Norway, the energy use in this segment is drastically increasing. Therefore, improving the energy performance of buildings becoming an urgent problem. Among technical systems in buildings, domestic hot water (DHW) systems have still significant untapped potential for energy saving. Storage tanks enable us to change DHW demand in buildings in a more energy-efficient and cost-effective way. However, to achieve this effect, the proper sizing and operation of the storage tanks are required. The aim of this study was to define a method for the DHW tank size optimization considering dynamic electricity prices and to assess how different electricity pricing methods would influence the DHW tank size. A dynamic discretized model of the DHW tank was used as a DHW tank model. Dynamic optimization was implemented as the optimization method to find the optimal tank charging rate based on the different pricing methods. Two pricing methods were considered in this study: 1) the current method with the fixed grid fee and 2) the power extraction method with the pricing of the maximum power extraction. The results showed that the electricity pricing pattern had significant impact on the DHW charging heating rate. In the case of the extraction fee pricing method, the charging rate was more stable over the day than in the case of the fixed grid fee. This stable charging rate gave stable DHW tank temperature over the day and the highest decrease in the total cost. A general conclusion was that the extraction grid fee pricing method would promote for stable charging over the day.
Environmental factors shaping assemblages of ostracods (Crustacea: Ostracoda) in springs situated in the River Krąpiel valley (NW Poland)
Authors: Szlauer-Łukaszewska Agnieszka , Pešić Vladimir , Zawal Andrzej
Published: March 2021

We investigated the ostracod assemblage structure in springs of a small lowland River Krąpiel valley. Environmental factors and the potential of ostracods as indicators of spring type were analysed. The analysis involved the type of spring, substrate, physicochemical parameters, and the river valley's hydrological status as environmental factors. A total of thirty ostracod species were recorded. The average count of ostracod individuals in a sample amounted to 100. The assemblages were dominated by juvenile Candona sp., juvenile Psychrodromus sp., Cypria ophtalmica, and Cypridopsis vidua. The spring species accounted for less than 1% of the individual counts, except for juvenile Psychrodromus sp. with 21% and Eucypris pigra with 4%. The average number of taxa per spring was 5. The ostracod assemblages were significantly influenced by limnocrene springs, spring flooding by the river overflow, the presence of coarse leaf litter, the presence of fine organic matter, a high content of NH4 as well as by BOD5, conductivity, pH, Fe, the river habitat modification index (RHM), the habitat modification score (HMS), and the river habitat quality (RHQ). The habitat conditions for the spring species appeared to be enhanced by the domination of mineral substrate over fine particulate organic matter, an elevated pH, the presence of leaf-derived organic matter, and the absence of flooding by the river. The spring species showed no association with the Krąpiel valley hydrological factors.
THEA-CODE: a design tool for the conceptual design of hybrid-electric aircraft with conventional or unconventional airframe configurations
Authors: Palaia Giuseppe , Zanetti Davide , Abu Salem Karim , Cipolla Vittorio , Binante Vincenzo
Published: March 2021

The aviation world is dealing with the development of new and greener aviation. The need for reducing greenhouse gas emission as well as the noise is a critical requirement for the aviation of the future. The aviation world is struggling with it, and a compelling alternative can be the electric propulsion. This work aims to present THEA-CODE, a tool for the conceptual design of hybrid-electric aircraft. The tool evaluates the potential benefits of the electric propulsion in terms of fuel burnt and direct and indirect CO2emissions. THEA-CODE is suitable not only for conventional “wing-tube” configurations but also for unconventional ones, such as the box-wing. The results show a significant reduction of fuel burnt adopting batteries with energy density higher than the current state of the art. A procedure to find the potential best compromise configurations is presented as well.
Tooth bending stress analysis of high speed curve face gear of composite transmission
Authors: Yu Yongquan , Lin Chao , Hu Yanan
Published: March 2021

To promote the engineering application of composite transmission of high speed curve face gear, which consists of a cylindrical gear and a high speed curve face gear, the analysis of tooth bending stress should be taken into consideration. High speed curve face gear pair is a new type of curve face gear pair. Combined with the principle of high speed cam and curve face gear pair transmission, it can transfer the axial/rotation composite motion and power between two intersecting shafts. Based on the gear engagement principle, the gear meshing coordinate system was established and the fundamental of the high speed composite transmission was expounded. Combined with the tooth profile equation of generating gear, the tooth surface equation of high speed curve face gear was gained. Tooth force, contact ratio and normal load distribution were calculated. Then the tooth bending stress of high speed curve face gear during the transmission was calculated and analyzed in detail. Influence of basic parameters on tooth bending stress was discussed. Finally, the simulation and measurement experiment of tooth bending stress was carried out. By the comparison analysis of simulation, experiment and theory, the correctness of tooth bending stress calculation method was verified, which has important guiding significance for the further research of high speed curve face gear of composite transmission.
The critical influence of La content on the microstructure-toughness relationship in the simulated coarse-grained heat-affected zone of high-strength low-alloy steels
Authors: Cao Yuxin , Wan Xiangliang , Zhou Feng , Dong Hangyu , Wu Kaiming , Li Guangqiang
Published: March 2021

The present study was envisaged to investigate the role of La content on the particle, microstructure and toughness in the simulated coarse-grained heat-affected zone (CGHAZ) of high-strength low-alloy steels. Three steels with La content of 0.016 wt.%, 0.046 wt.% and 0.093 wt.% were prepared and simulated in a 100 kJ/cm heat input welding thermal cycle. Subsequently, the particle and microstructure of selected specimens were characterized and the impact absorb energy was measured at −20 °C. The results indicated that the La2O2S inclusions in 0.016 wt.%-La steel were gradually modified to LaS-LaP in 0.046 wt.%-La steel and to LaP in 0.093 wt.%-La steel. A higher fraction of acicular ferrite was obtained in the simulated CGHAZ of 0.016 wt.%-La steel, since the inclusion of La2O2S was more powerful to induce the formation of acicular ferrite. Furthermore, the fraction of M-A constituents in the simulated CGHAZ increased with increasing La content. The impact toughness in the simulated CGHAZ of 0.016 wt.%-La steel was the highest, owing to the high fraction of the fine-grained acicular ferrite and low fraction of M-A constituent.
Planning of efficient trajectories in robotized assembly of aerostructures exploiting kinematic redundancy
Authors: Storiale Federica , Ferrentino Enrico , Chiacchio Pasquale
Published: March 2021

Aerospace production volumes have increased over time and robotic solutions have been progressively introduced in the aeronautic assembly lines to achieve high-quality standards, high production rates, flexibility and cost reduction. Robotic workcells are sometimes characterized by robots mounted on slides to increase the robot workspace. The slide introduces an additional degree of freedom, making the system kinematically redundant, but this feature is rarely used to enhance performances. The paper proposes a new concept in trajectory planning, that exploits the redundancy to satisfy additional requirements. A dynamic programming technique is adopted, which computes optimized trajectories, minimizing or maximizing the performance indices of interest. The use case is defined on the LABOR (Lean robotized AssemBly and cOntrol of composite aeRostructures) project which adopts two cooperating six-axis robots mounted on linear axes to perform assembly operations on fuselage panels. Considering the needs of this workcell, unnecessary robot movements are minimized to increase safety, the mechanical stiffness is maximized to increase stability during the drilling operations, collisions are avoided, while joint limits and the available planning time are respected. Experiments are performed in a simulation environment, where the optimal trajectories are executed, highlighting the resulting performances and improvements with respect to non-optimized solutions.
Initial value problem for fractional Volterra integrodifferential pseudo-parabolic equations
Authors: Phuong Nguyen Duc , Tuan Nguyen Anh , Kumar Devendra , Tuan Nguyen Huy
Published: March 2021

In this paper, we investigate a initial value problem for the Caputo time-fractional pseudo-parabolic equations with fractional Laplace operator of order 0 < ν ≤ 1 and the nonlinear memory source term. For 0 < ν < 1, the problem will be considered on a bounded domain of ℝd. By some Sobolev embeddings and the properties of the Mittag-Leffler function, we will give some results on the existence and the uniqueness of mild solution for problem (1.1) below. When ν = 1, we will introduce some Lp − Lq estimates, and based on them we derive the global existence of a mild solution in the whole space ℝd.
Non-constant positive solutions of a general Gause-type predator-prey system with self- and cross-diffusions
Authors: Xue Pan , Jia Yunfeng , Ren Cuiping , Li Xingjun
Published: March 2021

In this paper, we investigate the non-constant stationary solutions of a general Gause-type predator-prey system with self- and cross-diffusions subject to the homogeneous Neumann boundary condition. In the system, the cross-diffusions are introduced in such a way that the prey runs away from the predator, while the predator moves away from a large group of preys. Firstly, we establisha prioriestimate for the positive solutions. Secondly, we study the non-existence results of non-constant positive solutions. Finally, we consider the existence of non-constant positive solutions and discuss the Turing instability of the positive constant solution.
Diversity, geographical distribution, and prevalence ofEntamoebaspp. in Brazil: a systematic review and meta-analysis
Authors: dos Santos Zanetti Andernice , Malheiros Antonio Francisco , de Matos Tatiane Amorim , dos Santos Carolina , Battaglini Paula Franciene , Moreira Luciana Melhorança , Lemos Larissa Maria Scalon , Castrillon Solange Kimie Ikeda , da Costa Boamorte Cortela Denise , Ignotti Eliane , Espinosa Omar Ariel
Published: March 2021

The genusEntamoebaincludes a variety of widely distributed species adapted to live in the digestive tracts of humans and a large variety of animals of different classes. The objective of this study was to investigate the prevalence, distribution, and molecular epidemiology ofEntamoebaspp. in different classes of hosts in Brazil. Studies that analyzed hosts from several classes, including humans and domestic, wild, or captive animals, were considered. The pooled prevalence ofEntamoebaspp. was calculated using the random-effects model. A total of 166 studies on humans and 16 on animals were included. The prevalence ofEntamoebaspp. in the Brazilian population was 22% (95% CI: 21–24). The state with the highest prevalence was Paraiba with 72%, followed by Federal District with 53%, and Rondonia with 50%. In immunocompromized patients, the prevalence was 18%, and cancer (36%) was the most prevalent cause of immunosuppression. The prevalence ofEntamoebaspp. in animal hosts was 12% (95% CI: 7–17). Captive wild animals and domestic farm animals showed the highest prevalence, with 16% and 15%, respectively. The species found more often wereE. coli(86.5%),E. dispar(7.9%), andE. histolytica(3.1%). In conclusion, a high prevalence (22%) ofEntamoebaspp. was found in the Brazilian population, with a prevalence of up to 50% mainly in the northern, northeastern, and central-western regions. The pathogenic speciesE. histolyticais distributed in most Brazilian regions, with significant prevalence percentages. Among animals, unidentifiedEntamoebaspecies were most prevalent in mammals.
Foreign Direct Investment as a Driver of Economic Recovery and Business Innovation
Authors: Botelho José Manuel Macedo , Maksymova Irina , Padalka Oleg , Mamanazarov Mansur , Kulishov Volodymyr
Published: March 2021

Global economy is expected to contract, consequence of a collapse of international trade with millions of failed businesses and lost jobs. Foreign Direct Investment (FDI) flows are fundamental to support the economic recovery. Developed economies and developing economies in particular must make a great effort to restore and increase capital inflows, especially in form of foreign direct investment. FDI inflows have long been the largest source of finance investment. FDI is an opportunity to support the crucial economic recovery. An internationalization model of FDI is built in order to be a driver to governments and firms to implement a success strategy to attract FDI to the country.
Communicating the Foreign Policy Strategy: on Instruments and Means of Ministry of Foreign Affairs of Ukraine
Authors: Sheludiakova Natalia , Mamurov Bahodir , Maksymova Iryna , Slyusarenko Kateryna , Yegorova Iryna
Published: March 2021

The worldwide practice demonstrates that foreign policy of the states is often directed by a some set of strategic priorities referred to as foreign policy strategy. By communicating this strategy, states declare their intentions and prime concerns, which both aid their internal policy integrity and international perception as a consistent actor. Modern technology and media enable states to conduct systematic outreach or at least sporadically cover of their foreign policy priorities. The purpose of the article is to characterize the problems of application of communication tools in the foreign policy process and determine their role in forming a positive image of Ukraine in the modern world. As the mission of providing of foreign policy is vested in Ministry of Foreign Affairs of Ukraine, its communication practices and tools are examined. The raised issue involves the consideration of modern aspects of diplomacy and communication relations, including the concepts of public diplomacy, as well as media and digital diplomacy. Their tools and practices have been embraced by the Ministry of Foreign Affairs of Ukraine in order to convey some strategic foreign policy directions and state-branding messages, as the well-rounded foreign policy strategy is absent in Ukraine.
Use of Innovative Technologies in Training of Future Social Workers
Authors: Sanzharovets Valentyna , Petrenko Tetyana , Mietule Iveta , Platash Larysa , Kostyk Liubov
Published: March 2021

The article considers the actual problem of using the innovative technologies during the educational process in higher education institutions for training of future social workers. Professionalism in the activities of a social worker is in constant motion. Actions that take place in a society require constant professional changes in methods and technologies of social work. Social work is inseparable from society as a whole and is aimed at the population. Designing in social work is a constructive, complex, creative activity, the essence of which is in advanced reflection of reality in order to transform the personality of oneself, own life situation and the surrounding world with the help of a social worker. Social work refers to the category of innovative, creative technologies, because it involves a change of reality. It is based on the existing life situation, which can be unified, mastered and refined. A social worker is the initiator of innovation, the purpose of which is to create, modernize or maintain in a changed environment material or spiritual value of people, recognized as positive in its social value.
The relationship between rotator cuff integrity and acromiohumeral distance following open and arthroscopic rotator cuff repair
Authors: Kholinne Erica , Kwak Jae-Man , Sun Yucheng , Kim Hyojune , Park Dongjun , Koh Kyoung Hwan , Jeon In-Ho
Published: March 2021

Background: Acromiohumeral distance (AHD) has become both a diagnostic and prognostic parameter related to rotator cuff pathology which is always measured in a 2-dimensional plane. The purposes of this study were (1) to evaluate the regional AHD with MRI following open and arthroscopic rotator cuff repair and, (2) to investigate its association to the rotator cuff integrity following medium to large size rotator cuff repair with open and arthroscopic manner. Methods: A retrospective review of 112 patients who were treated for full-thickness medium to large size rotator cuff tears either by open repair (open group) or arthroscopic repair (arthroscopic group) was done. All patients included in the study are those with at least 12 and 18 months for the post-operative MRI and clinical follow-up. Propensity score matching was used to select controls matched for age, sex, body mass index, tear size, and affected site. There were 56 patients in each group with a mean age of 63.3 years (range, 50 to 77 years). The post-operative functional and radiologic outcomes for both groups were compared. AHD was measured at three regions of interest (ROI) with MRI and compared pre-and post-operatively. Results: AHD was significantly greater in the open group when measured at the anterior third of the lateral acromion border compare to the arthroscopic group (p = 0.005). The re-tear rate was affected by AHD at the anterior third of the lateral border of the acromion for the arthroscopic and open group (p = 0.021, p = 0.029). The AHD measured at the anterior and middle third of lateral acromion border were significantly greater in healed compared to the re-tear rotator cuff group (p = 0.019, p = 0.022). Conclusions: Open rotator cuff repair showed greater AHD at the anterior third of the lateral border of the acromion. Regional AHD measured at anterior third of the lateral border of acromion significantly associated with rotator cuff integrity following repair. Level of evidence: propensity-matched case-control (Level II)
The management of acute knee dislocations: A global survey of orthopaedic surgeons’ strategies
Authors: Venter Santa-Marie , Dey Roopam , Khanduja Vikas , von Bormann Richard PB , Held Michael
Published: March 2021

Purpose: Great variety and controversies surround the management strategies of acute multiligament knee injuries (aMKLIs) and no established guidelines exist for resource-limited practices. The aim of this study was to compare the management approach of acute knee dislocations (AKDs) by orthopedic surgeons from nations with different economic status. Methods: This descriptive cross-sectional scenario-based survey compares different management strategies for aMLKIs of surgeons in developed economic nations (DEN) and emerging markets and developing nations (EMDN). The main areas of focus were operative versus non-operative management, timing and staging of surgery, graft choice and vascular assessment strategies. The members of the Societe Internationale de Chirurgie Orthopedique et de Traumatologie (SICOT) were approached to participate and information was collected regarding their demographics, experience, hospital setting and management strategies of aMLKIs. These were analyzed after categorizing participants into DEN and EMDN based on the gross domestic product (GDP) per capita. Results: One-hundred and thirty-eight orthopedic surgeons from 47 countries participated in this study, 67 from DEN and 71 (51.4%) from EMDN. DEN surgeons had more years of experience and were older (p < 0.05). Surgeons from EMDN mostly worked in public sector hospitals, were general orthopedic surgeons and treated patients from a low-income background. They preferred conservative management and delayed reconstruction with autograft (p < 0.05) if surgery was necessary. Surgeons from DEN favored early, single stage arthroscopic ligament reconstruction. Selective Computerized Tomography Angiography (CTA) was the most preferred choice of arterial examination for both groups. Significantly more EMDN surgeons preferred clinical examination (p < 0.05) and duplex doppler scanning (p < 0.05) compared to DEN surgeons. More surgeons from EMDN did not have access to a physiotherapist for their patients. Conclusions: Treatment of aMLKIs vary significantly based on the economic status of the country. Surgeons from DEN prefer early, single stage arthroscopic ligament reconstruction, while conservative management is favored in EMDN. Ligament surgery in EMDN is often delayed and staged. EMDN respondents utilize duplex doppler scanning and clinical examination more readily in their vascular assessment of aMLKIs. These findings highlight very distinct approaches to MLKIs in low-resource settings which are often neglected when guidelines are generated.
Personalized alignment in total knee arthroplasty: current concepts
Authors: Lustig Sébastien , Sappey-Marinier Elliot , Fary Camdon , Servien Elvire , Parratte Sébastien , Batailler Cécile
Published: March 2021

Traditionally in total knee arthroplasty (TKA), a post-operative neutral alignment was the gold standard. This principle has been contested as functional outcomes were found to be inconsistent. Analysis of limb alignment in the non-osteoarthritic population reveals variations from neutral alignment and consideration of a personalized or patient-specific alignment in TKA is challenging previous concepts. The aim of this review was to clarify the variations of current personalized alignments and to report their results. Current personalized approaches of alignment reported are: kinematic, inverse kinematic, restricted kinematic, and functional. The principle of “kinematic alignment” is knee resurfacing with restitution of pre-arthritic anatomy. The aim is to resurface the femur maintaining the native femoral joint line obliquity. The flexion and extension gaps are balanced with the tibial resection. The principle of the “inverse kinematic alignment” is to resurface the tibia with similar medial and lateral bone resections in order to keep the native tibial joint line obliquity. Gap balancing is performed by adjusting the femoral resections. To avoid reproducing extreme anatomical alignments there is “restricted kinematic alignment” which is a compromise between mechanical alignment and true kinematic alignment with a defined safe zone of alignment. Finally, there is the concept of “functional alignment” which is an evolution of kinematic alignment as enabling technology has progressed. This is obtained by manipulating alignment, bone resections, soft tissue releases, and/or implant positioning with a robotic-assisted system to optimize TKA function for a patient’s specific alignment, bone morphology, and soft tissue envelope. The aim of personalizing alignment is to restore native knee kinematics and improve functional outcomes after TKA. A long-term follow-up remains crucial to assess both outcomes and implant survivorship of these current concepts.
Konflikte in der neuen Rolle
Authors: Holtschmidt Ilona
Published: March 2021

Sei es ein Wechsel von der Pflegekraft zur Stationsleitung oder aus dieser Rolle hin in die Pflegedirektion – Rollenkonflikte sind immer vorprogrammiert. Und das nicht nur im beruflichen Setting, auch zu Hause kann ein Rollenwechsel die ganze Familie betreffen.
Raus aus dem Elfenbeinturm
Authors: Schoberer Daniela , Nordhausen Thomas , Vetsch Janine
Published: March 2021

Die Pflegeforschung ist im Vergleich zur medizinischen Forschung noch eine relativ junge Disziplin. Der Theorie-Praxis-Transfer ist dabei ein komplexer Prozess, der auf verschiedenen Ebenen ansetzen muss. Pflegedirektoren nehmen hier eine Schlüsselrolle ein.
Meningeal Carcinomatosis for Prostate Adenocarcinoma Mimicking Chronic Subdural Hematoma: Case Report and Literature Review
Authors: Ferreira Tiago Silva Holanda , Aguiar Gilnard Caminha de Menezes , Távora Daniel Gurgel Fernandes , Albuquerque Lucas Alverne Freitas de , Filho Stélio da Conceição Araújo
Published: March 2021

Introduction Cerebral metastases are the most common cancer of the central nervous system (CNS). Meningeal infiltration by neoplasms that did not originate in the CNS is a rare fact that is present in 0.02% of the autopsies.

Epidemiologically, the radiological presentation mimicking a subdural hematoma is even more uncommon. We report a case of meningeal carcinomatosis by an adenocarcinoma of the prostate mimicking a chronic subdural hematoma.

Case Report A 60-year-old male patient was diagnosed with prostate cancer in 2011. He underwent radical resection of the prostate, as well as adjuvant hormonal therapy and chemotherapy.

Five years later, the patient presented peripheral facial paralysis that evolved with vomiting and mental confusion. Tomography and magnetic resonance imaging scans confirmed the subdural collection.

At surgery, the dura was infiltrated by friable material of difficult hemostasis. The anatomicopathological examination showed atypical epithelial cells. The immunohistochemistry was positive for prostate-specific antigen (PSA) and other key markers, and it was conclusive for meningeal carcinomatosis by a prostate adenocarcinoma.

Discussion Meningeal carcinomatosis presents clinically with headache, motor deficits, vomiting, changes in consciousness and seizures.

The two most discussed mechanisms of neoplastic infiltration are the hematogenous route and retrograde drainage by the vertebral venous plexus.

Conclusion Variable clinical presentations may occur in dural metastases; however, the radiological presentation as subdural hematoma is rare. There are few descriptions of cases like this one in the literature.

To support the diagnosis, the previous medical history is as important as the complementary exams and the radiological findings, because the symptoms are common at the neurological emergency. To our knowledge, this is the first report of a prostate neoplasm mimicking chronic subdural hematoma in Brazil.