bluuebunny/crossref_metadata_2025 huggingface dataset:
Eigenvalue Switching by Cascading
Authors: Torner Lluis , Torres Juan P.
Published: February 2023

Self-action of light is a subject of constant intense investigation due to the fascinating phenomena encountered and their potential applications to all-optical, ultrafast signal processing devices. Optical solitons play a central role in such scenario because of their unique particlelike properties. Until recently optical solitons have been mainly pursued using the optical Kerr effect in cubic nonlinear media, and the photorefractive effect. The propagation of light in cubic nonlinear media is described by the nonlinear Schröedinger (NLSE) which in appropriate waveguide settings has both single and higher-order soliton solutions, and various types of devices based on such solitons have been proposed. Higher-order solitons are bound states of several single solitons. In the framework of the inverse scattering transform the number of solitons of the NLSE contained into an input light signal is given by the number of eigenvalues of the Zakharov-Shabat scattering The bound states contain no binding energy and they can be destroyed by different physical mechanisms that appear as perturbations to the NLSE.
Nonlinear Optical Loop Mirrors with Feedback and a Slow Nonlinearity
Authors: Blow K. J. , Manning R. J. , Poustie A. J.
Published: February 2023

The fibre-based nonlinear optical loop mirror (NOLM)[1] has been one of the most successful devices for demonstrating a range of all-optical processing functions. Recently, the SLALOM [2] or TOAD [3] configuration has been developed where a semiconductor optical amplifier (SOA) is used as the nonlinear material in a fibre loop, rather than the fibre itself. The lack of full recovery in the amplifier causes an interaction between adjacent pulses in the input pulse stream which, for example, can lead to patterning effects in data demultiplexing [4]. This pulse interaction combined with optical feedback leads to an enhancement of the dynamics on timescales much shorter than the feedback time. In this work involving the TOAD/SLALOM with feedback, we have observed spontaneous clock division as a result of the non-zero response times of the SOA.
Bright Soliton-Like Pulses in Self-Defocusing Material
Authors: Bélanger N. , Villeneuve A. , Aitchison J. S.
Published: February 2023

Temporal bright solitons are well known and still studied because they provide a great potential in long distance lightwave systems. Bright temporal solitons have been observed [1] in silica fiber in which the Kerr nonlinearity (n2) is positive and the dispersion anomalous (β2<0). Since bright solitons exist as long as n2 and β2 are of opposite sign, another regime is possible and was observed recently [2] near the band gap in AlGaAs waveguide having a self-defocusing nonlinearity and normal dispersion. In this case, the solitonic feature can be deduced from a temporal narrowing of the pulse with increasing input pulse peak power. For pulses of increasing peak power, the self-phase modulation better compensates the dispersion. Nevertheless it still not possible to conclude in a solitonic phenomenon in a strict way since no information was obtain about the spectrum. If an important spectral broadening with increasing pulse peak power occurs, it would clearly deny the soliton hypothesis. In this presentation we propose to introduce spectral measurements and to qualify the pulse behavior.
Dark Solitons and the Third-Order Dispersion
Authors: Afanasjev Vsevolod V. , Kivshar Yuri S.
Published: February 2023

Recent experimental demonstration of data transmission based on dark solitons [1] has renewed the efforts to the use this type of soliton for various optical applications. Although generation of a modulated stream of dark solitons is a more difficult task than that of bright ones, dark solitons are believed to display some advantages over bright solitons, including lower Gordon-Haus jitter [2]. At the same time, one of the main problems associated with dark-soliton signal transmission is higher average power. In order the reduce the power, the operational wavelength should be selected closer to the zero group-velocity dispersion. Hence, the dark soliton propagation can be affected by the third-order dispersion.
Timing jitter reduction in a fiber laser mode-locked by an input bit stream
Authors: Niculae Anne , Kath William L.
Published: February 2023

It has been demonstrated experimentally that an input data stream can be used to mode-lock a fiber laser, thus providing an efficient all-optical method for clock recovery.1-3 In the experiments, the incoming data pulses passed along a length of dispersion shifted fiber (DSF) that formed part of the ring laser cavity. The laser and signal wavelengths were chosen such that they straddled the zero dispersion point of the DSF, so that little walk-off occurred during propagation. In this manner, the two signals interacted through cross-phase modulation, producing sufficient phase modulation to mode-lock the ring laser cavity.
Soliton Jitter Suppression by a Copropogating Support Structure
Authors: Shipulin Arcady , Onishchukov George , Malomed Boris A.
Published: February 2023

The Gordon-Haus (GH) jitter is one of the most serious problems in designing soliton-based optical communication networks [?]. Different ways to suppress the jitter have been proposed [?], [?]. Nevertheless, search for alternative means allowing to stabilize the long-haul soliton transmission against the random jitter remains an important problem.
Higher-order self-guided mode solitary waves in diffractive quadratic media
Authors: Haelterman M. , Trillo S. , Ferro P.
Published: February 2023

These last years have witnessed growing interest in the subject of self-trapping of light beams in quadratic optical media. Potential applications of self-trapped beams to all-optical switching based on the light-guiding-light concept has motivated intense research activities which have led to rapid theoretical and experimental progress [1]. As an example, the so-called parametric or two-wave soliton of quadratic media has been experimentally observed in planar waveguides [2]. The interest of this soliton for all-optical switching has been examined theoretically in ref. [3]. Mutual interactions between solitons are the key processes for this type of application. In our communication we show the existence of new parametric solitary-waves which, for certain parameters, consist of bound states of several separate solitons. These bound states are stationary, which means that the interaction forces between solitons have been annealed. This suggests that, besides their fundamental aspect, the new solitary waves have potential interest as regards applications based on soliton interactions.
Stability of three-wave parametric solitons in diffractive quadratic media
Authors: Buryak Alexander V. , Kivshar Yuri S. , Trillo Stefano
Published: February 2023

We analyze the existence and stability of three-wave [(1 + 1) and (2+1) dimensional] quadratic solitons and present the analytic stability criterion which is also verified numerically.
Experimental processing of light pulses with quadratic nonlinearity in type II phase-matched conditions: switching, phase modulation, phase conjugation, transistor operation
Authors: Lefort L. , Barthelemy A.
Published: February 2023

The scope of this paper is to revisit the use of quadratic crystals cut for second harmonic generation (SHG) with type II phase-matching in view of all-optical processing of light signal. The investigations on this topic mainly focused in the past years on the possibilities opened by cascading of quadratic nonlinearities in phase-mismatched conditions [1]. The goal of this paper is to remind the reader that various types of optical processing are achievable with sum and difference frequency generation in phase-matched position without the requirement for cascaded nonlinearities. In a first part we will report few examples of the use of difference frequency generation (or down conversion) for signal processing. In a second part we will show that type II SHG with unbalanced fundamental inputs may lead to coherent amplification or transistor like operation.
Self- and Cross-Phase Modulation of Chirped Pulses: Spectral Imaging of Pulse Temporal Profile
Authors: Mouradian L.K. , Froehly C. , Louradour F. , Barthelemy A.
Published: February 2023

We present a new technique for measuring puise temporal profiles at the femtosecond time scale using a direct real-time method based on the nonlinear-optic Fourier transformation process (NOFT). NOFT has been previously implemented in the spectral compressor (SC) and consist in a dispersive delay line (DDL) followed by a nonlinear single-mode lightguide [1]. In DDL pulses are stretched experiencing a negative chirp, and in the nonlinear fiber the chirp quenching due to self- or cross-phase modulation (SPM/XPM) leads to spectral narrowing.
Nonlinear Bragg diffraction and solitary waves in multi-dimensional resonant periodic structures
Authors: Mantsyzov B. I.
Published: February 2023

The formation and propagation of nonlinear solitary waves under Bragg condition in 2D and 3D periodic resonant structures is described by analytical and numerical solutions of two-wave diffraction Maxwell-Bloch equations. The existence of nonlinear solitary waves both in the Bragg and in the Laue geometry of diffraction has been shown. The dynamics of gap pulse amplification in gain grating is also studied.
Solitary waves in quadratic media with local distortion of phase mismatch
Authors: Lee Wangkeun , Kim Hongki , Cha Myoungsik
Published: February 2023

In media with quadratic nonlinearity spatial solitary waves can be created by mutual trapping of the fundamental and the second-harmonic waves. Such solitary waves, as they are soliton-like waves, retain the original beam width and intensity to some extent. Nevertheless, intensity fluctuation and depletion have been significant problems in addition to that a long propagation length is needed before forming a stable solitary wave.
Active localization in planar tapered waveguides with random index of refraction modulations and saturable gain nonlinearity
Authors: Afeyan Bedros B. , Ratowsky Richard P.
Published: February 2023

We use a nonparaxial, slow temporal envelope evolution code (2D SOFTSTEP) to study the new phenomenon of spatial localization in the presence of random fluctuations and nonlinear amplification in planar waveguides. Optical bistability and transmission-resonance switching are manifestations of this active localization in such a medium and are contrasted with their conterparts in media with Kerr nonlinearity and periodic index modulations.
Oscillating solutions of the multidimensional nonlinear Schroedinger equation
Authors: Chavez-Cerda S. , Meneses-Nava M. A. , Sanchez-Villicana V. , Sanchez-Mondragon J.
Published: February 2023

We show analytically that there can exist oscillating bound states of the multidimensional nonlinear Schroedinger equations with Kerr and saturable nonlinearity which are breather-like solutions. The solutions have a rare peculiarity, the oscillating behavior takes place between the widths, with the amplitude kept almost constant. We confirm numerically our results.
Switching in low-temperature-grown InGaAs MQWs
Authors: Takahashi Ryo
Published: February 2023

Optical communication systems capable of operating at ultrafast speeds and transmitting massive volumes of data will comprise the pillars that support the multimedia society of the future. To achieve such systems, it will be necessary to increase the speed of optical demultiplexers, optical repeaters, and other optical control devices making up today' selectronic circuits. A key device in such systems will be the ultrafast all-optical switch. Over the years, research institutes around the world have been conducting research aimed at achieving such switches through the use of semiconductors, optical fibers, and various other materials. Semiconductors are the most promising materials because they offer the possibility of achieving devices with superior practical aspects, including compact size. One drawback of semiconductor-based optical switches, however, has been the difficulty in achieving both high-speed photoresponse and a high on/off ratio.
Anomalous interaction of spatial solitons in photorefractive media
Authors: Królikowski Wieslaw , Saffman Mark , Luther-Davies Barry , Denz Cornelia
Published: February 2023

The nature of the forces between mutually coherent interacting solitons has been discussed in the literature for both temporal as well as spatial solitons [1-2]. It has been established that in the case of homogenous self-focusing media the interaction force depends on the relative phase of the solitons. In particular, two in-phase solitons attract while out-of-phase solitons repel. Phase-sensitive attraction, repulsion, and fusion of spatial solitons have been demonstrated in experiments with various nonlinear media including liquids [3], glass waveguides [4], atomic vapours [5], and photorefractive crystals [6].
Massive WDM with Solitons
Authors: Mollenauer Linn F. , Mamyshev P. V.
Published: February 2023

To meet the present demands of system builders, we are attempting to develop massive (many hundreds of Gbit/s total capacity) WDM at per-channel rates of 10 Gbit/s or higher, robust and error-free over transoceanic distances. We believe that this can be done only by combining the very best version of dispersion-managed solitons, sliding-frequency filters, and fibers with improved (low-slope) dispersion characteristics. Experimental results will be reviewed.
Waveguides induced by photorefractive screening solitons
Authors: Shih Ming-feng , Chen Zhigang , Mitchell Matthew , Segev Mordechai , Lee Howard , Feigelson Robert S. , Wilde Jeffrey P.
Published: February 2023

Photorefractive spatial solitons form when the optically induced space-charge field modifies the refractive index via electro-optic effect and forms a waveguide that confines the optical beam that has induced the waveguide. Since the photorefractive response is wavelength-dependent, one can generate a soliton with a weak beam and guide in it a more intense beam of a less-photosensitive wavelength. Here we present theoretical and experimental studies of the waveguides induced by photorefractive screening solitons. We show that the number of guided modes in a waveguide induced by a bright screening soliton increases monotonically with increasing intensity-ratio (the ratio between the peak soliton intensity and the background or dark irradiance) whereas the waveguides induced by dark screening solitons are always single-mode waveguides.
An experimental investigation of Stokes pulse energy noise in an optical fiber Raman generator
Authors: Baiocchi David , Her Peng , Sidereas Panagiotis , Thompson John R.
Published: February 2023

In Raman generation photons from an intense pump pulse are spontaneously scattered into a red-shifted Stokes pulse. The spontaneously generated Stokes pulse is then amplified by stimulated scattering as it propagates with the pump pulse, and it grows at an exponential rate until it begins to significantly deplete the pump. This coupling of a random start-up with exponential growth produces a macroscopic Stokes pulse with a highly unpredictable energy. [1-4] There has been extensive work on the pulse energy statistics associated with Raman generation in high pressure gas cells [1,2], but there has been very little work on Raman generation in a waveguide geometry. [3,4] In a waveguide the transverse spatial mode of the pump and Stokes light can be tightly controlled, permitting maximum spatial overlap between the two signals; furthermore, the use of optical fiber permits long interaction lengths for long temporal pulses where dispersive walk-off between the Stokes and pump pulses is minimal. [5] Multiple order Stokes generation occurs at modest pump powers in a waveguide, allowing one to investigate the coupling between pulse energy fluctuations of different Stokes orders. We will present a systematic experimental study of the pulse energy statistics of the first Stokes order under conditions of multi-order Raman generation in single-mode optical fiber. This study will look at the evolution of the pulse energy statistics and histograms as the scattering strength changes. The role played by the broad Raman gain spectrum of glass in shaping the statistics of the generated light will also be discussed.
Switching of short pulses in nonlinear directional couplers: effects due to the dispersion of the coupling coefficient
Authors: Chiang Kin Seng , Shum Ping
Published: February 2023

Nonlinear directional couplers have attracted considerable attention because of their potential applications in all-optical switching (see, for example, Refs.1 and 2, and references therein). The conventional way of analyzing pulse switching in an evanescent-field nonlinear coupler is based on solving the linearly coupled nonlinear Schrödinger equations.1,2 Recently, it has been found that these equations are valid only when the dispersion properties of the coupling coefficient can be ignored.3,4 In many practical situations, however, the coupling-coefficient dispersion can be important and must be included in the analysis.3,4 It has been shown, both theoretically3-5 and experimentally,6 that a dispersive coupling coefficient can cause pulse distortion, or even pulse breakup. In this paper, using a two-core fiber as an example, we first identify the situations under which the coupling-coefficient dispersion is important, and then demonstrate how the coupling-coefficient dispersion affects the switching dynamics of short pulses in a nonlinear coupler.
Stable dark and vortex parametric solitons due to competing nonlinearitie
Authors: Buryak Alexander V. , Alexander Tristram J. , Kivshar Yuri S.
Published: February 2023

We demonstrate how the influence of a weak Kerr effect in quadratic nonlinear media can eliminate parametric modulational instability of plane waves, leading to the existence of stable dark and vortex spatial solitons.
Four-wave mixing of the fundamental, Stokes and anti-Stokes waves in a single-mode birefringerent fiber: influence of initial conditions on nonlinear dynamics of exchange among the waves.
Authors: Podoshvedov S.A.
Published: February 2023

In this paper, we consider interaction of the fundamental wave polarized both along fast and slow axes of the single-mode birefringerent fiber with Stokes and anti-Stokes waves with orthogonal polarizations

2

ω
0

=

ω
1

+

ω
2

. The evolution equations can be derived from the wave equation in the slowly varying envelope approximation. For example, we present equation describing dynamics of Stokes wave E1: where Δk is mismatch of the wave vectors.
Efficient three-level continuous-wave and GHz passively mode-locked laser by a Nd3+-doped silicate glass single mode fiber
Authors: Wang Yafei , Sun Yan , Wang Xin , Chen Yinggang , Shao Chongyun , Wang Shikai , Zhang Lei , Chen Danping , Yu Chunlei , Hu Lili
Published: February 2023

Nd3+-doped three-level (4F3/2–4I9/2) fiber lasers with wavelengths in the range of 850–950 nm are of considerable interest in applications such as bio-medical imaging and blue and ultraviolet laser generation. Although the design of a suitable fiber geometry has enhanced the laser performance by suppressing the competitive four-level (4F3/2–4I11/2) transition at ∼1 µm, efficient operation of Nd3+-doped three-level fiber lasers still remains a challenge. In this study, taking a developed Nd3+-doped silicate glass single-mode fiber as gain medium, we demonstrate efficient three-level continuous-wave lasers and passively mode-locked lasers with a gigahertz (GHz) fundamental repetition rate. The fiber is designed using the rod-in-tube method and has a core diameter of 4 µm with a numerical aperture of 0.14. In a short 4.5-cm-long Nd3+-doped silicate fiber, all-fiber CW lasing in the range of 890 to 915 nm with a signal-to-noise ratio (SNR) greater than 49 dB is achieved. Especially, the laser slope efficiency reaches 31.7% at 910 nm. Furthermore, a centimeter-scale ultrashort passively mode-locked laser cavity is constructed and ultrashort pulse at 920 nm with a highest GHz fundamental repetition is successfully demonstrated. Our results confirm that Nd3+-doped silicate fiber could be an alternative gain medium for efficient three-level laser operation.
Dynamic generation of photonic spatial quantum states with an all-fiber platform
Authors: Alarcón A. , Argillander J. , Spegel-Lexne D. , Xavier G. B.
Published: February 2023

Photonic spatial quantum states are a subject of great interest for applications in quantum communication. One important challenge has been how to dynamically generate these states using only fiber-optical components. Here we propose and experimentally demonstrate an all-fiber system that can dynamically switch between any general transverse spatial qubit state based on linearly polarized modes. Our platform is based on a fast optical switch based on a Sagnac interferometer combined with a photonic lantern and few-mode optical fibers. We show switching times between spatial modes on the order of 5 ns and demonstrate the applicability of our scheme for quantum technologies by demonstrating a measurement-device-independent (MDI) quantum random number generator based on our platform. We run the generator continuously over 15 hours, acquiring over 13.46 Gbits of random numbers, of which we ensure that at least 60.52% are private, following the MDI protocol. Our results show the use of photonic lanterns to dynamically create spatial modes using only fiber components, which due to their robustness and integration capabilities, have important consequences for photonic classical and quantum information processing.
Highly efficient diode-pumped passively Q-switched Nd:YVO4/KGW Raman lasers at yellow and orange wavelengths
Authors: Chen Jian-Cheng , Tu Yueh-Chi , Ho Yu-Wen , Liang Hsing-Chih , Chen Yung-Fu
Published: February 2023

Efficient diode-pumped passively Q-switched Nd:YVO4 yellow and orange lasers are developed with the pulse pumping scheme and the intracavity stimulated Raman scattering (SRS) and second harmonic generation (SHG). A Np-cut KGW is exploited in the SRS process to generate the yellow 579 nm laser or the orange 589 nm laser in a selectable way. The high efficiency is achieved by designing a compact resonator to include a coupled cavity for intracavity SRS and SHG and to provide a focused beam waist on the saturable absorber for reaching an excellent passive Q-switching. The output pulse energy and peak power can reach 0.08 mJ and 50 kW for the orange laser at 589 nm. On the other hand, the output pulse energy and peak power can be up to 0.10 mJ and 80 kW for the yellow laser at 579 nm.
High-density integrated delay line using extreme skin-depth subwavelength grating waveguides
Authors: Ahmed Ishtiaque , Ahmed Syed Z. , Jaidye Nafiz , Borhan Mia Md , Bernussi Ayrton , Kim Sangsik
Published: February 2023

Optical delay lines control the flow of light in time, introducing phase and group delays for engineering interferences and ultrashort pulses. Photonic integration of such optical delay lines is essential for chip-scale lightwave signal processing and pulse control. However, typical photonic delay lines based on long spiral waveguides require extensively large chip footprints, ranging from mm2 to cm2 scales. Here we present a scalable, high-density integrated delay line using a skin-depth engineered subwavelength grating waveguide, i.e., an extreme skin-depth (eskid) waveguide. The eskid waveguide suppresses the crosstalk between closely spaced waveguides, significantly saving the chip footprint area. Our eskid-based photonic delay line is easily scalable by increasing the number of turns and should improve the photonic chip integration density.
Generalized optical signal-to-noise ratio monitoring using a convolutional neural network for digital coherent receivers
Authors: Cho Hyung Joon
Published: February 2023

In this Letter, we propose a generalized optical signal-to-noise ratio (GOSNR) monitoring scheme using a convolutional neural network trained on constellation density features acquired from a back-to-back setup and demonstrate accurate GOSNR estimations for links having different nonlinearities. The experiments were carried over dense wavelength division multiplexing links configured on 32-Gbaud polarization division multiplexed 16-quadrature amplitude modulation (QAM) and demonstrated that the GOSNRs are estimated within 0.1 dB mean absolute error with maximum estimation errors below 0.5 dB on metro class links. The proposed technique does not require any information about the noise floor in the conventional spectrum-based means and therefore is readily deployable for real-time monitoring.
Profiling the knowledge of female medical/para-medical students, and expertise of health care professionals on female genital schistosomiasis in Anambra, South Eastern Nigeria
Authors: Aribodor Ogechukwu B. , Mogaji Hammed O. , Surakat Olabanji A. , Azugo Nwadiuto O. , Jacob Eunice C. , Obikwelu Emmanuel M. , Nebe Obiageli J. , Jacobson Julie
Published: February 2023

Background

Female genital schistosomiasis (FGS) is a largely neglected tropical disease (NTD), with little or no attention in the primary health care unit. Towards building momentum to address this challenge, we investigated the perception of medical and para-medical students about FGS, as well as the expertise of health care professionals in Anambra State, Nigeria.

Methodology

We conducted a cross-sectional survey among 587 female medical and para-medical university students (MPMS), and 65 health care professionals (HCPs) saddled with the responsibility of delivering care for schistosomiasis-affected persons. Pretested questionnaires were administered to document the awareness and knowledge about the disease. In addition, the expertise of HCPs vis-à-vis suspicion of FGS and management of FGS patients during routine health care service were documented. Data were subjected to descriptive, chi-square tests and regression analysis in R software.

Results

Over half of the students recruited; 54.2% for schistosomiasis and 58.1% for FGS, were not aware of the disease. Knowledge about schistosomiasis was associated with student’s year of study, with those in 2nd (OR: 1.66, 95% CI: 1.0, 2.7), 4th (OR: 1.97, 95% CI: 1.2, 3.2), and 6th (OR: 5.05, 95% CI: 1.2, 34.2) year having higher likelihoods of been more informed about schistosomiasis. For HCPs, we observed a contrastingly high knowledge about schistosomiasis (96.9%), but low knowledge about FGS (61.9%). Knowledge for both schistosomiasis and FGS was not associated with year of practice and expertise (95% OR included 1, p > 0.05). A considerable proportion (>40%) of the HCPs never suspected schistosomiasis during routine clinical diagnosis of patients who presented probable FGS symptoms (p < 0.05). Similarly, only 20% were certain about the use of praziquantel for treating FGS, and about 35% were uncertain of the eligibility criteria and dosage regimens. Commodities for managing FGS were also largely unavailable in about 39% of the health facilities where the HCPs operate.

Conclusion

Awareness and knowledge about FGS among MPMS and HCPs were poor in Anambra, Nigeria. It is therefore important to invest in innovative methods of building capacity of MPMS and HCPs, with complementary provision of necessary diagnostics to perform colposcopy, as well as competence to diagnose pathognomonic lesions using diagnostic atlas or Artificial Intelligence (AI).
First and second wave dynamics of emergency department utilization during the COVID-19 pandemic: A retrospective study in 3 hospitals in The Netherlands
Authors: Dijk Robi , Plaum Patricia , Tummers Stan , van Osch Frits H. M. , Barten Dennis G. , Latten Gideon H. P.
Published: February 2023

Objective

During certain phases of the COVID-19 pandemic, a decrease was observed in emergency department (ED) utilization. Although this phenomenon has been thoroughly characterized for the first wave (FW), second wave (SW) studies are limited. We examined the changes in ED utilization between the FW and SW, compared to 2019 reference periods.

Study design and methods

We performed a retrospective analysis of ED utilization in 3 Dutch hospitals in 2020. The FW and SW (March-June and September–December, respectively) were compared to the reference periods in 2019. ED visits were labeled as (non-)COVID-suspected.

Results

During the FW and SW ED visits decreased by 20.3% and 15.3%, respectively, when compared to reference periods in 2019. During both waves high urgency visits significantly increased with 3.1% and 2.1%, and admission rates (ARs) increased with 5.0% and 10.4%. Trauma related visits decreased by 5.2% and 3.4%. During the SW we observed less COVID-related visits compared to the FW (4,407 vs 3,102 patients). COVID-related visits were significantly more often in higher need of urgent care and ARs were at least 24.0% higher compared to non-COVID visits.

Conclusion

During both COVID-19 waves, ED visits were significantly reduced. ED patients were more often triaged as high urgent, the ED length of stay was longer and ARs were increased compared to the reference period in 2019, reflecting a high burden on ED resources. During the FW, the reduction in ED visits was most pronounced. Here, ARs were also higher and patient were more often triaged as high urgency. These findings stress the need to gain better insight into the motives of patients to delay or avoid emergency care during pandemics, as well as to better prepare EDs for future outbreaks.
Everyday navigation between adaptation and resistance: How young people negotiate their well-being in relation to assigned migrant positions in school
Authors: Lögdberg Ulrika , Öhlander Magnus , Nilsson Bo
Published: February 2023

Concerning the so-called “refugee crisis” in 2015 and how it affected the position of young migrants in society, researchers have underscored the value of studies challenging one-sided images of migrant youth. This study examines how migrant positions are constituted, negotiated, and related to young people’s well-being. The study was undertaken using an ethnographic approach combined with the theoretical concept of translocational positionality to acknowledge how positions are created through historical and political processes and, at the same time, are context-dependent over time and space and thus contain incongruities. Our findings show how the newly arrived youth used multiple ways to navigate the school’s everyday life and ascribed migrant positions to achieve well-being as illustrated through the distancing, adapting, defense, and the contradictory positions. Based on our findings, we understand the negotiations that occur in forming migrant positions within the school as asymmetric. At the same time, the youths’ diverse and often contradictory positionality showed in various ways the striving for increased agency and well-being.
Association between serum ferritin level and decreased diffusion capacity 3 months after the onset of COVID-19 pneumonia
Authors: Shinfuku Kyota , Takasaka Naoki , Fukuda Taiki , Chida Kentaro , Suzuki Yudai , Shibata Shun , Kojima Ayako , Hasegawa Tsukasa , Yamada Masami , Yamanaka Yumie , Hosaka Yusuke , Seki Aya , Seki Yoshitaka , Takeda Hiroshi , Ishikawa Takeo , Kuwano Kazuyoshi
Published: February 2023

Background

Coronavirus disease 2019 (COVID-19) pneumonia can have prolonged sequelae and lead to respiratory dysfunction, mainly because of impaired diffusion capacity for carbon monoxide (DLCO). The clinical factors associated with DLCO impairment, including blood biochemistry test parameters, remain unclear.

Methods

Patients with COVID-19 pneumonia who underwent inpatient treatment between April 2020 and August 2021 were included in this study. A pulmonary function test was performed 3 months after onset, and the sequelae symptoms were investigated. Clinical factors, including blood test parameters and abnormal chest shadows on computed tomography, of COVID-19 pneumonia associated with DLCO impairment were investigated.

Results

In total, 54 recovered patients participated in this study. Twenty-six patients (48%) and 12 patients (22%) had sequelae symptoms 2 and 3 months after, respectively. The main sequelae symptoms at 3 months were dyspnea and general malaise. Pulmonary function tests showed that 13 patients (24%) had both DLCO <80% predicted value (pred) and DLCO/alveolar volume (VA) <80% pred, and appeared to have DLCO impairment not attributable to an abnormal lung volume. Clinical factors associated with impaired DLCO were investigated in multivariable regression analysis. Ferritin level of >686.5 ng/mL (odds ratio: 11.08, 95% confidence interval [CI]: 1.84–66.59; p = 0.009) was most strongly associated with DLCO impairment.

Conclusions

Decreased DLCO was the most common respiratory function impairment, and ferritin level was a significantly associated clinical factor. Serum ferritin level could be used as a predictor of DLCO impairment in cases of COVID-19 pneumonia.
Are pediatricians responsible for maintaining high MMR vaccination coverage? Nationwide survey on parental knowledge and attitudes towards MMR vaccine in Serbia
Authors: Loncarevic Goranka S. , Jovanovic Aleksa Lj , Kanazir Milena S. , Kisic Tepavcevic Darija B. , Maric Gorica D. , Pekmezovic Tatjana D.
Published: February 2023

Aim

To assess parental knowledge and attitudes related to MMR vaccination and to determine factors associated with parental decision whether to vaccinate their child with MMR vaccine in Serbian population.

Methods

The selection of participants was performed using multi-phase sampling. Seventeen out of the total 160 public health centers on the territory of Republic of Serbia were randomly selected. All parents of children up to the age of 7 who visited the pediatrician at the public health centers from June to August 2017 were recruited. Parents filled in an anonymous questionnaire regarding their knowledge, attitudes and practices in immunization with MMR vaccine. The relative contribution of different factors was explored by univariable and multivariable logistic regression analysis.

Results

The majority of parents were female (75.2%), with mean age of 34.3 ± 5.7 years, and the average age of children was 4.7 ± 2.4 years, 53.7% of them were girls. In the multivariable model, getting information on vaccination from a pediatrician was associated with 7.5 fold increased probability to vaccinate child with MMR vaccine (OR = 7.52; 95% CI 2.73–20.74; p<0.001), while previous vaccination of the child increased this chance two times (OR = 2.07; 95% CI 1.01–4.27; p = 0.048), and having two children was associated with 84% increase in chance of vaccinating child with MMR vaccine compared to having one child or three or more children (OR = 1.84; 95% CI 1.03–3.29; p = 0.040).

Conclusion

Our study emphasized the key role of pediatricians in the formation of parental attitude on MMR vaccination of their child.
Determinants of good vitamin A consumption in the 12 East Africa Countries using recent Demographic and health survey
Authors: Wolde Maereg , Tessema Zemenu Tadesse
Published: February 2023

Background

Vitamin A one of the important micronutrients that it cannot be made in the human body and must be taken from outside the body through the diet. Ensuring that vitamin A is available in any form in sufficient quantities remains a challenge, especially in regions where access to vitamin A-containing foods and healthcare interventions is limited. As a result, vitamin A deficiency (VAD) becomes a common form of micronutrient deficiency. To the best of our knowledge, there is limited evidence on determinants of good Vitamin A consumption in East African countries. Therefore, this study aimed to assess the magnitude and determinants of good vitamin A consumption in East African countries.

Methods

A recent Demographic and Health Survey (DHS) of twelve East African countries were included to determine the magnitude and determinants of good vitamin A consumption. A total of 32,275 study participants were included in this study. A multilevel logistic regression model was used to estimate the association between the likelihood of good vitamin A-rich food consumption. Both community and individual levels were used as independent variables. Adjusted odds ratio and its 95% confidence interval were used to see the strength of the association.

Result

The pooled magnitude of good vitamin A consumption was 62.91% with a 95% CI of 62.3 to 63.43. The higher proportion of good vitamin A consumption 80.84% was recorded in Burundi and the smallest good vitamin A consumption 34.12% was recorded in Kenya. From the multilevel logistic regression model, women’s age, marital status, maternal education, wealth index, maternal occupation, children’s age in a month, media exposure, literacy rate, and parity were significantly associated with good vitamin A consumption in East Africa.

Conclusion

The magnitude of good vitamin A consumption in twelve East African countries is low. To increase good vitamin A consumption health education through the mass media and enhancing the economic status of women is recommended. Planners and implementers should give attention and priority to identified determinants to enhance good vitamin A consumption.
Serological and histopathological assessment of galactose-deficient immunoglobulin A1 deposition in kidney allografts: A multicenter prospective observational study
Authors: Sofue Tadashi , Oguchi Hideyo , Yazawa Masahiko , Tsujita Makoto , Futamura Kenta , Nishihira Morikuni , Toyoda Mariko , Kano Toshiki , Suzuki Hitoshi
Published: February 2023

Background

Recurrent immunoglobulin A (IgA) nephropathy is an important risk factor for kidney allograft loss. However, there is no classification system for IgA deposition in kidney allografts based on serological and histopathological evaluation of galactose-deficient IgA1 (Gd-IgA1). This study aimed to establish a classification system for IgA deposition in kidney allografts based on serological and histological evaluation of Gd-IgA1.

Methods

This multicenter prospective study included 106 adult kidney transplant recipients in whom an allograft biopsy was performed. Serum and urinary Gd-IgA1 levels were investigated in 46 transplant recipients who were IgA-positive and classified into four subgroups according to the presence or absence of mesangial Gd-IgA1 (KM55 antibody) deposits and C3.

Results

Minor histological changes without an acute lesion were observed in recipients with IgA deposition. Fourteen (30%) of the 46 IgA-positive recipients were KM55-positive and 18 (39%) were C3-positive. The C3 positivity rate was higher in the KM55-positive group. Serum and urinary Gd-IgA1 levels were significantly higher in KM55-positive/C3-positive recipients than in the other three groups with IgA deposition. Disappearance of IgA deposits was confirmed in 10 of 15 IgA-positive recipients in whom a further allograft biopsy was performed. The serum Gd-IgA1 level at the time of enrollment was significantly higher in recipients in whom IgA deposition continued than in those in whom it disappeared (p = 0.02).

Conclusions

The population with IgA deposition after kidney transplantation is serologically and pathologically heterogeneous. Serological and histological assessment of Gd-IgA1 is useful for identifying cases that should be carefully observed.
Sticky cost determinants: Which one has the stronger impact?
Authors: Soegiharto Michelle , Rachmawati Dyna
Published: February 2023

Sticky cost is a phenomenon that can occur in companies and it is an unbalanced response of costs to changes in output. Since it can reduse company profits, it should not occur. Therefore, it is important to know the determinants that influence it so that the company can control properly redusing it. The aim of this research is to test which the determinants that have the impact of Covid-19, asset intensity, employee intensity, equity intensity, management incentives, profitability, and intellectual capital on sticky cost.This research is a quantitative research with Â object of manufacturing companies listed on the Indonesia Stock Exchange with observation period of 2019-2020. This research uses financial data from annual report and summary of minutes General Meeting of Shareholders. The sample selection technique used purposive sampling method. This research involved two data analysis techniques. There are multiple linear regression for main test and logistic regression for additional test. The results of the main test show that employee intensity and intellectual capital have impact on sticky cost. But, the Covid-19, asset intensity, equity intensity, management incentives, and profitability have no impact on sticky cost. The main test result is supported by the additional test, in term of first, intellectual capital has impact on sticky cost. Second, the other determinants remain no impact on sticky cost. The implications of this research are management should be carefull to make investment in intangible assets and use employee intensive. As those determinants can increase sticky cost.
The effect of covid-19 on bank proftability: Evidence of m-banking and e-banking in Indonesia
Authors: Anggraeni Anggraeni , Basuki Basuki , Setiawan Rahmat
Published: February 2023

Covid-19 affected the banksâ€™ financial acitivities globally and, therefore, mobile banking can become solution for doing a distancing transaction. This study tries to observe if mobile transaction has significant effect of income in private and public bank in Indonesia. This study collects the data about bank profitability and the number of mobile banking users before and during Covid-19 pandemic from BCA and BNI in Indonesia. The data of mobile transaction is divided into three, mobile, internet, and SMS banking. The data of income divided into two, premium/net and operational income. The data is analyzed using linear regression method to observe if mobile transaction has effect toward income variables. The data is analyzed using SPSS. The result showed that before pandemic, those three mobile transaction have strong correlation toward the increasing number of net and total operational income in BNI. In BCA, mobile banking has a significant effect on net and total operational income. During pandemic, mobile transactions have negative correlation toward net income, while operational income has positive one for BNI, but negative for BCA. It can be concluded that Â internet, mobile, and SMS banking have correlation toward net and total operational income.
Effects of the temperature on activity patterns and torpor in Saccolaimus saccolaimus in Bangladesh with notes on its morphometrics and roosting behaviour
Authors: Reza AHM Ali , Saha Anik , Mostafa Feeoz Mohammed , Hasan Md. Kamrul
Published: February 2023

Saccolaimus saccolaimus is one of the six Emballonurid bats and the only species from the genus Saccolaimus that occurs in South and Southeast Asia. This species utilizes tree hollows, damaged palm trees, and occasionally artificial structures as roosts. We recorded a total of 22 bats from 10 colonies located at two dormitories in Jahangirnagar University (JU) in a sub-urban setting in central Bangladesh. The number of bats per colony varied between 1-9 individuals, with an average of four bats per colony. We found that the colonies of S. saccolaimus emerged from roosting sites when the temperature was 22.5°C or higher. The highest bat activity was recorded in September (79.66 mins) when the air temperature was 27.66°C, and the lowest was in January (47.01 mins) when the air temperature was 17.46°C. We observed variations in bat activity in different months, and bat activity was strongly correlated (R-square = 0.52) with air temperature. The most extended torpor period for the colonies was recorded for 27 days. The mean weight for male S. saccolaimus in JU was 41.66 ± 0.29 (41.46-42) g, whereas for females was 45.32 ± 3.08 (43.14- 47.5) g. Although some variation was observed in the morphological measurements, the morphometric analysis indicated no significant differences between specimens from Bangladesh and the neighbouring countries. Further research is needed to understand various ecological aspects of S. saccolaimus in Bangladesh. Therefore, to do so, the existing colonies on JU campus should be extensively monitored.
Metallogenic model of the Hongqiling Cu–Ni sulfide intrusions, Central Asian Orogenic Belt: Insight from long-period magnetotellurics
Authors: Xu Zhi-He , Gu Guan-Wen , Jiang Ji-Yi , Li Fei-Da , Niu Xing-Guo
Published: February 2023

The Hongqiling magmatic Cu–Ni sulfide deposit is one of the most important deposits in the easternmost segment of the Central Asian Metallogenic Belt, northeast China. However, the existence or non-existence of magmatic chambers is still not been determined, which is the key to decipher the formation of Hongqiling Cu–Ni deposit. Therefore, this study proposes to adopt long-period magnetotellurics method to image the deep-seated metallogenic system in Hongqiling Cu–Ni deposit. Two-dimensional (2D) nonlinear conjugate gradient inversion technology allows us to describe entire magma plumbing system, including the mantle-derived magma channels (banded low-resistivity anomalies), deep separated chamber (low-resistivity anomaly C2), and shallow magma conduits (low-resistivity anomaly C1). These results indicated that the mantle-derived primitive magma gave rise to the parental magma for the mafic–ultramafic intrusions in Hongqiling Cu–Ni deposit and triggered the segregation of Cu–Ni sulfides in the shallow chamber. By combining the experimental simulation, geochemistry, geochronology, and geotectonics data in the study area, we suggest that the partial melting processes which produced the large magma plumbing system probably have been triggered by lithospheric delamination.
Die Seidenstraßeninitiative in deutschen Medien – eine frameanalytische Langzeitstudie
Authors: Wang Yuanmeng
Published: February 2023

In den letzten Jahren verfolgen die deutschen Medien die chinesische „Seidenstraßeninitiative“ mit steigender Aufmerksamkeit. Dieser Artikel führt eine diachrone Analyse der relevanten Berichte über das Thema „Seidenstraßeninitiative“ von fünf deutschen Nachrichtenmedien im Zeitraum von 2013 bis 2020 durch. Ziel dieser systematischen Untersuchung der deutschen Presseberichterstattung ist, die Veränderung der Medienframes zur „Seidenstraßeninitiative“ in deutschen Berichterstattungen zu analysieren. Das Ergebnis der Studie zeigt, dass die Medienframes der „Seidenstraßeninitiative“ in den deutschen Medien im Laufe der Zeit eine Dynamik in ihrer Stabilität und der Negativierung aufweisen.
Evaluation and analysis of teaching quality of university teachers using machine learning algorithms
Authors: Zhong Ying
Published: February 2023

In order to better improve the teaching quality of university teachers, an effective method should be adopted for evaluation and analysis. This work studied the machine learning algorithms and selected the support vector machine (SVM) algorithm to evaluate teaching quality. First, the principles of selecting evaluation indexes were briefly introduced, and 16 evaluation indexes were selected from different aspects. Then, the SVM algorithm was used for evaluation. A genetic algorithm (GA)-SVM algorithm was designed and experimentally analyzed. It was found that the training time and testing time of the GA-SVM algorithm were 23.21 and 7.25 ms, both of which were shorter than the SVM algorithm. In the evaluation of teaching quality, the evaluation value of the GA-SVM algorithm was closer to the actual value, indicating that the evaluation result was more accurate. The average accuracy of the GA-SVM algorithm was 11.64% higher than that of the SVM algorithm (98.36 vs 86.72%). The experimental results verify that the GA-SVM algorithm can have a good application in evaluating and analyzing teaching quality in universities with its advantages in efficiency and accuracy.