Interesting Phenomena Research Articles

Non-additive effect: Variation in the effects of the interaction between primitive components in anaerobic digestion

Inherent characteristics of complex organic components and their interactive coupling with environmental factors limit the comprehensive understanding of biotransformation in anaerobic digestion. In this study, we elucidated the mechanism underlying an interesting phenomenon, where a non-additive effect for methane production was recorded when primitive components, i.e., alpha-cellulose (α-CE), xylan (XY), and alkali lignin (AL), were used. The interaction of α-CE and XY produced a supra-additive effect due to the reduction of the energy barrier of carbonyl compound degradation. The degradation of non-conjugated CO, with lower kinetic stability, was preferred to the degradation of conjugated CO. The introduction of AL produced a sub-additive effect, and AL exerted a stronger inhibitory effect on the methanogenesis of XY than α-CE. The preferential change in the relevant structural units occurred due to the deposition of AL on the surface of XY or the wrapping of XY by AL. In this study, we described a multiphase integrated influence mechanism, which can be used to more effectively design anaerobic co-digestion strategies and achieve the controlled enhancement of methane yield of perishable organic solid waste.

Influence of non-gravitational forces on the co-orbital motion

ABSTRACT In the Solar system, there exist many non-gravitational perturbations for co-orbital objects, such as the solar radiation pressure, Yarkovsky effect, and so forth. Their effects play important roles in the dynamics of co-orbital objects as they lead to long-term perturbations accumulating. The motivation of this paper is to investigate the general mechanism of the non-gravitational force on the co-orbital motion in the circular restricted three-body problem. We propose an effective method for perturbed co-orbital motions by analysing the locus of the co-orbital objects in a two-dimensional map. Several expressions derived uncover how the non-gravitational force acts on orbital parameters. Taking the Sun–Jupiter system as an example, we implement numerical computations to demonstrate the validity of our results. Numerical computation shows that most of loci of co-orbital motions are in agreement with our conclusions. Some interesting phenomena of perturbed co-orbital motion, such as the co-orbital transition and escape, are found and explained. The results obtained from this paper provide an efficient approach to analyse the evolution of perturbed co-orbital motions.

Interprofessional education in undergraduate dental curricula: A systematic review.

Health professionals who effectively communicate and coordinate their work increase patient safety and quality of care. Therefore, an interprofessional education (IPE) program may be a valuable addition to the curriculum of health science courses. This study aims to verify how IPE has been implemented in undergraduate dental program curricula. This is a qualitative systematic review performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with qualitative and qualitative-quantitative studies selected in the period between 2011 and 2021. The guiding question was as follows: how has IPE been implemented in undergraduate dentistry curricula around the world? The quality of the included articles was assessed using the CASP Qualitative Checklist (2018). After the review, 22 studies were selected and data were extracted following the acronym PICo (Population, phenomenon of Interest, and COntext). The majority of studies in which IPE is included in Dentistry come from North American universities. Regarding the IPE teaching methodology, the use of active methodologies was observed and the interprofessional skills most common were role clarity, teamwork, and communication. This systematic review indicated that Dentistry is included in interprofessional activities in many studies around the world, and primarily with colleagues in medicine, nursing, and pharmacy programs. IPE teaching takes place through the use of active methodologies and develops important skills for interprofessional work.

Chiral Induced Spin Selectivity.

Since the initial landmark study on the chiral induced spin selectivity (CISS) effect in 1999, considerable experimental and theoretical efforts have been made to understand the physical underpinnings and mechanistic features of this interesting phenomenon. As first formulated, the CISS effect refers to the innate ability of chiral materials to act as spin filters for electron transport; however, more recent experiments demonstrate that displacement currents arising from charge polarization of chiral molecules lead to spin polarization without the need for net charge flow. With its identification of a fundamental connection between chiral symmetry and electron spin in molecules and materials, CISS promises profound and ubiquitous implications for existing technologies and new approaches to answering age old questions, such as the homochiral nature of life. This review begins with a discussion of the different methods for measuring CISS and then provides a comprehensive overview of molecules and materials known to exhibit CISS-based phenomena before proceeding to identify structure-property relations and to delineate the leading theoretical models for the CISS effect. Next, it identifies some implications of CISS in physics, chemistry, and biology. The discussion ends with a critical assessment of the CISS field and some comments on its future outlook.

Spontaneous Recycling of Electrosprayed Sample by Retrograde Motion of Microdroplets.

Here, we discuss an interesting phenomenon occurring spontaneously near the sample liquid meniscus at the tip of the electrospray emitter. While most ejected droplets move from the emitter tip toward the counter electrode, some of the droplets decelerate and move backward to the liquid meniscus. When they hit the surface of the liquid meniscus, they either merge with the bulk liquid or get recharged during intermittent contact with the liquid meniscus and immediately reaccelerate toward the counter electrode. In some cases, while in contact with the meniscus they spontaneously form a secondary Taylor cone and emit progeny droplets. This observation suggests that the amount of electric charge transferred to such a droplet is sufficient to surpass the Rayleigh limit. Similar effects were previously observed for water as well as for NaCl-water and ethanol-water mixtures. However, here we observed it for electrolyte solutions commonly used in electrospray ionization mass spectrometry: methanol-water solutions with the addition of ammonium acetate, formic acid, or ammonium hydroxide. The reported phenomenon reveals the ongoing recycling of sample liquid in electrosprays. Such recycling can contribute to enhancement of sample utilization efficiency in electrospray ionization.

Tricritical state and quasi-periodicity triggered by the non-linear elasticity in an Upper Convected Maxwell fluid confined between two co-oscillating cylinders about zero-mean

The effects of harmonically co-oscillating the inner and outer cylinders about zero mean rotation in a Taylor–Couette flow are examined numerically using Floquet theory, for the case where the fluid confined between the cylinders obeys the upper convected Maxwell model. Although stability diagrams and mode competition involved in the system were clearly elucidated recently by Hayani Choujaa et al. (2021) in weakly elastic fluids, attention is focused, in this paper, on the dynamic of the system at higher elasticity with emphasis on the nature of the primary bifurcation. In this framework, we are dealing with pure inertio-elastic parametric resonant instabilities where the elastic and inertial mechanisms are considered of the same order of magnitude. It turns out, on the one hand, that the fluid elasticity gives rise, at the onset of instability, to the appearance of a family of new harmonic modes having different axial wavelengths and breaking the spatio-temporal symmetry of the base flow: invariance in the axial direction generating the O(2) symmetry group and a half-period-reflection symmetry in the azimuthal direction generating a spatio-temporal Z2 symmetry group. On the other hand, new quasi-periodic flow emerging in the high frequency limit and other interesting bifurcation phenomena including bi and tricritical states are also among the features induced by the fluid elasticity. Lastly, and in comparison with the Newtonian configuration of this system, the fluid elasticity leads to a total suppression of the non-reversing flow besides emergence of instabilities with lower wavelengths. Such a comparison provides insights into the dynamics of elastic hoop stresses in altering the flow reversal in modulated Taylor–Couette flow.

The Single-Photon Scattering Properties of Three-Level Giant Atoms under the Interaction of Dissipation and Local Coupling

The coupling of three-level giant atoms with one-dimensional waveguides can show interesting phenomena of transmission and reflection. Since the non-waveguide mode can cause the dissipation of external atoms, we consider the effect of the dissipation rate on the scattering of single photons in the system with giant atom–waveguide coupling. We find that as the dissipation rate of giant atoms increases, the transmission rate of a single photon increases and the reflection rate decreases. In addition, by varying the phase difference and decay rate, the giant atoms are able to achieve perfect transmission and total reflection over the entire frequency range. We also find and show the conditions for the conversion of the optimal frequency. When the cumulative phase of photons reaches a certain value, the system can achieve perfect transmission, which is independent of frequency. This model of coupling giant atoms with waveguides has a promising application in quantum communication and quantum information processing.

Gradualism, bifurcation and fading qualia

Abstract When reasoning about dependence relations, philosophers often rely on gradualist assumptions, according to which abrupt changes in a phenomenon of interest can result only from abrupt changes in the low-level phenomena on which it depends. These assumptions, while strictly correct if the dependence relation in question can be expressed by continuous dynamical equations, should be handled with care: very often the descriptively relevant property of a dynamical system connecting high- and low-level phenomena is not its instantaneous behaviour but its stable fixed points (those in the vicinity of which it spends most of the time, after comparatively short transitory periods), and stable fixed points can change abruptly as a result of infinitesimal changes of the low-level phenomenon. We illustrate this potential gradualist trap by showing that Chalmers’ fading qualia argument falls into it.

Physical Properties, Chemical Components, and Transport Mechanisms of Atmospheric Aerosols Over a Remote Area on the South Slope of the Tibetan Plateau

AbstractThe physicochemical properties and origins of atmospheric aerosols in the Tibetan Plateau (TP) region are a research topic of great interest, but an in‐depth understanding of this topic is challenging, partially due to a lack of intensive in situ observations. Thus, a field campaign was conducted over Yadong, a remote area on the south slope of the TP from June 11 to 31 August 2021. The aerosol loading was low, with a black carbon mass concentration of 147.4 ± 98.4 ng·m−3. Aerosol single‐scattering albedo was low (0.73 ± 0.11 at 550 nm) and increased from 450 to 700 nm wavelength. Organic matter (OM) accounting for 69.6% of the total aerosol mass and relatively high secondary organic carbon ratios, highlighting the importance of secondary formation. An interesting phenomenon observed was that the evolution of aerosols was mainly characterized by diurnal variation, which could not be explained by large‐scale atmospheric processes such as Indian summer monsoon. Instead, it was found that regional mountain‐valley winds between the Himalayas and South Asia transported polluted air masses toward the TP, especially in the afternoon when regional valley wind are expected to be the strongest and the boundary layer in South Asia is deepest. Additionally, daytime local valley wind further elevated these aerosols to higher altitudes on the TP. This paper provides insights into the transport mechanisms of aerosols from South Asia to the TP. These findings are of great importance since aerosols exhibit significant diurnal variations in the TP region.

When the antidote is the poison: Investigating the relationship between people's social media usage and loneliness when face-to-face communication is restricted.

When governments mandated lockdowns to limit the spread of the coronavirus, the resulting reduction of face-to-face communication threatened many people's psychological well-being by fostering feelings of loneliness. Given social media's eponymous social nature, we study the relationship between people's social media usage and their loneliness during these times of physical social restrictions. We contrast literature highlighting the social value of social media with a competing logic based on the "internet paradox," according to which increased social media usage may paradoxically be associated with increasing, not decreasing, levels of loneliness. As the extant literature provides opposing correlational insights into the general relationship of social media usage and loneliness, we offer competing hypotheses and offer novel longitudinal insights into the phenomenon of interest. In the empirical context of Germany's initial lockdown, our research uses survey panel data from February 2020 (before the lockdown) and April 2020 (during the lockdown) to contribute longitudinal evidence to the matter. We find that more usage of social media in the studied lockdown setting is indeed associated with more, not less loneliness. Thus, our results suggest a "social media paradox" when physical social restrictions are mandated and caution social media users and policy makers to not consider social media as a valuable alternative for social interaction. A post-hoc analysis suggests that more communication via richer digital media which are available during physical lockdowns (e.g., video chats) softens the "social media paradox". Conclusively, this research provides deeper insights into the social value of social interactions via digital media during lockdowns and contributes novel insights into the relationship between social media and loneliness during such times when physical social interaction is heavily restricted.

Transient quasi-periodic oscillations in the gamma-ray light curves of bright blazars

ABSTRACT Transient quasi-periodic oscillations (QPOs) are extremely interesting observational phenomena. However, the precise physical mechanisms leading to their generation are still hotly debated. We performed a systematic search for transient QPO signals using Weighted Wavelet Z-transforms on the gamma-ray light curves of 134 bright blazars with peak flux exceeding 1 × 10−6 ph cm−2 s−1 as monitored by Fermi-LAT. Artificial light curves were generated from the power spectral density and probability distribution functions of the original light curves to assess the significance level of transient QPO. We discuss several physical mechanisms that produce transient QPOs, with the helical jet model providing the best explanation. This study identified four new transient QPO events. Interestingly, repetitive transient QPOs are observed in PKS 0537-441, and nested transient QPOs are detected in PKS 1424−41. Additionally, we find that transient QPOs tend to occur in the flare state of the blazar. Finally, we estimate the incidence of transient QPO events to be only about 3 per cent.

Studying the nulling, subpulse drifting, and moding in PSR J1921+1948 with the FAST

ABSTRACT We reported the observations of nulling, subpulse drifting, and moding of radio radiation in pulsar (PSR) B1918+19 at 1250 MHz with the Five-hundred-meter Aperture Spherical radio Telescope. The nulling fraction is 2.6 ± 0.1 per cent and no periodicity of nulling can be seen. We confirmed the existence of three different drift modes (A, B, C) and a disordered mode (N) at 1250 MHz. Unlike the other three modes where the second component of the average pulse profile dominates, the first component of the average pulse profile in mode C is brighter than the other components, the second component shifts forward and the fourth component shifts backward. The bidrifting phenomenon is observed in PSR B1918+19, the drifting of the first and second components is positive, and the drift direction of the fourth component is negative. The drifting rate of the drift bands composed of the first and second components has an obvious evolutionary trend. Mode B has a short duration and no clear trend can be seen. But for mode A, the drift rate of each drift band starts relatively fast, then slows down to a steady state, and finally increases slowly until it enters either null or mode N. Further analysis shows that the emergence and significant variation in the drifting period of multidrifting subpulse emission modes for PSR B1918+19 may be due to the aliasing effect. The interesting subpulse emission phenomenon of PSR B1918+19 at different frequencies provides a unique opportunity to understand the switching mechanism of the multidrift mode of the pulsars.

Language Maintenance Bali Aga Dialect of Tigawasa Village in Education Domain

Language maintenance bali aga dialect of Tigawasa village in education domain is an interesting language phenomena to be studied from a sociolinguistic perspective. The purpose of this study is to provide an overview of the maintenance of the Bali aga dialect in the education domain in Tigawasa Village. This research uses a mixed-method approach. Data collection was carried out using field observation, structured interviews, documentation and questionnaires. The results showed that the language maintenance of the bali aga dialect is very good and high in the education domain. The dominant use of the bali aga dialect makes it easier for students to understand the teaching and learning process. Supporting factors for the language maintenance of the bali aga dialectin the education domain in Tigawasa Village are 1) The background of the speaker who is a native of Tigawasa Village 2) The positive attitude of speakers who always use the bali aga dialect in the education domain 3) The desire and pride to preserve regional culture, especially in the bali aga dialect. The dominance of the use of the bali aga dialect facilitates students' understanding of the teaching and learning process. There are two strategies in the language maintenance of the bali aga dialect 1) the bali aga dialect is used as a communication tool in teaching and learning activities 2) the bali aga dialect is used in community/extracurricular.

Experiment and first-principles calculation to investigate the phenomenon of Gd and Y elemental enrichments in the long-period stacking ordered phase

In this study, the Gd and Y elemental enrichment in long-period stacking ordered (LPSO) phases has been systematically studied by combining energy dispersive X-ray spectrometry (EDS) diagram and first-principles calculation. This phenomenon differs from the ordinary type of LPSO phase, which consists of only one rare earth element. It is highly likely that the observed effect is attributed to the preferential formation of the Mg-Y-Zn LPSO phase, which is subsequently replaced by the Gd element to form more stable Mg-Gd-Y-Zn LPSO phases. The results of the formation enthalpy and energy suggest that the most probable situation is one group of Gd (four atoms) replacing the Y atoms. The electronic properties and elastic properties were performed to investigate the bonding character and mechanical stability. It can be found that the substitutional doping of the Gd element is able to improve bonding strength and increase anisotropy. Therefore, this research explains the interesting phenomenon of Gd and Y elemental enrichment for in-depth understanding of LPSO phases, and provides valuable data that can be utilized for designing rare-earth magnesium alloys with improved properties.

Indonesian Twitter Users’ Language Attitude Towards English-Indonesian Code-mixing

Social media users need language as a tool to communicate, both in verbal and written form. Over time, the language used in social media also shows some significant growth. Talking about language in social media, there is an interesting phenomenon recently on social media that can be reached within the internet, namely the code-mixing of Indonesian and English (which in Indonesian are also popularly known as Jaksel language, Keminggris, Kemlondo, Indoglish, Englonesian, or Bahasa Gado-gado). This study is aimed to find out the attitudes of 500 Indonesian Twitter users towards English-Indonesian code-mixing with a questionnaire. This study uses a descriptive-quantitative approach. For the result of each aspect, it shows a quite positive indication: Cognitive aspect 2.92, Affective aspect 2.75, and Conative 2.79. If the three aspects being summed up, also indicated a quite positive attitude towards the code-mixing with point or score 2.82. The attitudes come from many reasons and factors, such as the need for understandability in communication, language prestige, prepossessing or attracting attention, confidence, and language aptitude.

Supercritical Fluids as Solvents for the Future

High pressure technologies involving sub and supercritical fluids offer the possibility to obtain new products with special characteristics or to design new processes, which are environmentally friendly and sustainable. Supercritical fluids are flexible tools for processing materials. Supercritical fluids have been applied to mass-transfer processes, phase-transition processes, reactive systems, materials-related processes, and nanostructured materials. In addition to extraction, application areas include impregnation and cleaning, multistage countercurrent separation, particle formation, coating, and reactive systems such as hydrogenation, biomass gasification, and supercritical water oxidation. Polymers are modified with supercritical fluids, and colloids and emulsions as well as nanostructured materials exhibit interesting phenomena when in contact with supercritical fluids that can be industrially exploited.

Observation of time-reversal symmetry breaking in the band structure of altermagnetic RuO2.

Altermagnets are an emerging elementary class of collinear magnets. Unlike ferromagnets, their distinct crystal symmetries inhibit magnetization while, unlike antiferromagnets, they promote strong spin polarization in the band structure. The corresponding unconventional mechanism of time-reversal symmetry breaking without magnetization in the electronic spectra has been regarded as a primary signature of altermagnetism but has not been experimentally visualized to date. We directly observe strong time-reversal symmetry breaking in the band structure of altermagnetic RuO2 by detecting magnetic circular dichroism in angle-resolved photoemission spectra. Our experimental results, supported by ab initio calculations, establish the microscopic electronic structure basis for a family of interesting phenomena and functionalities in fields ranging from topological matter to spintronics, which are based on the unconventional time-reversal symmetry breaking in altermagnets.

Operads, Operadic Categories and the Blob Complex

We will show that the Morrison–Walker blob complex appearing in Topological Quantum Field Theory is an operadic bar resolution of a certain operad composed of fields and local relations. As a by-product we develop the theory of unary operadic categories and study some novel and interesting phenomena arising in this context.

Analysis of discharge events in the CMS GE1/1 GEMdetectors in presence of LHC beam

In July 2022, the experiments installed on the Large Hadron Collider (LHC) accelerator ring started a new data taking phase, Run-3. Before this period, an upgrade campaign took place during the so called Long Shutdown 2 (2018–2022). In particular, the muon system of the CMS experiment has been upgraded with the installation of a new gas detector station, GE1/1, based on Gas Electron Multiplier technology (GEM). The CMS experiment has scheduled the installation of two additional GEM stations: GE2/1 and ME0. The aim of the GEM stations is to maintain the performance of the muon system, reached during the last data taking phase (Run-2), with the increase of instantaneous luminosity expected at the LHC. The installed GE1/1 station covers the pseudorapidity region 1.55 <|η|< 2.18. GE1/1 participated in the CMS Run-3 data taking from July to November 2022 and, in this period, its detectors were exposed for the first time to the radiation produced during the collisions of the LHC beams, with a center of mass energy of 13.6 TeV. Since the first days of Run-3, where only a few bunches collided in CMS, the GE1/1 detectors started to experience a significant number of discharges, affecting their smooth operation during the data taking. In this talk, we present an analysis of discharges, which started by simply counting the number of discharges occurring per detector. An interesting phenomenon observed was that the discharge rate can vary a lot among the installed detectors; this is due to the fact that the occurrence of discharges is driven by the manufacturing of the GEM foils used in the detectors. Imperfections in their manufacturing can lead to large variation in the discharge rate. In addition, the rate can vary in time, due to the fact that discharges can produce damage at the site generating them, deactivating a particular hole or, in the worst case, producing a short circuit in the GEM foil, deactivating a part of the foil amplification region. We present the evolution of the discharge rate in time and its dependence on the HV working point and on the luminosity delivered by the LHC beams. This contribution illustrates the actions taken to mitigate the discharge rate and to assure a smooth detector operation.

Factors influencing the work of researchers in Scientific Initiation: A systematic review protocol.

Scientific Initiation (SI) is an educational activity that allows students to begin their scientific training and research under the guidance of an experienced researcher. While several studies have examined students' perceptions of SI, research on the perspective of researchers working in this field is currently lacking. Thus, this study's aim is to describe the protocol design for conducting a systematic review. At the same time, the review aims also to identify factors influencing the work of researchers in SI and explore the motivations leading researchers to engage in research projects within institutions and their respective impacts. Literature search will be done using the bibliographic databases, including Academic Search Premier, APA PsycNet, CINAHL Plus, ERIC, SocINDEX, Scopus, and Web of Science. The search strategy was guided by the PICo framework (Population, phenomenon of Interest, and Context). The preparation and development of this protocol following guidelines were employed: Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Protocols 2015 (PRISMA-P 2015), Peer Review of Electronic Search Strategies 2015 (PRESS 2015), and PRISMA-Search (PRISMA-S). Original, peer-reviewed articles that examine the factors related to the work of researchers in SI will be included without any language or publication date restrictions. Qualitative, quantitative, and mixed-methods studies will be screened by two independent researchers. The included studies will be analyzed to identify factors, policies, and their impacts obtained analytically. Findings will be objectively categorized and synthetically represented through figures, diagrams, and graphic models. The risk of bias will be assessed using the Critical Appraisal Skills Program (CASP) and the Downs and Black checklists. A third senior reviewer will resolve any discrepancies. We aim to understand the factors that drive researchers to engage in SI research through the dissemination of the findings of this systematic review. This may aid the development of institutional strategies and actions that can support the enhancement of SI programs and encourage greater researcher participation.