Theory Of Decay Research Articles

An integrated machine-learning model to predict nucleosome architecture.

We demonstrate that nucleosomes placed in the gene body can be accurately located from signal decay theory assuming two emitters located at the beginning and at the end of genes. These generated wave signals can be in phase (leading to well defined nucleosome arrays) or in antiphase (leading to fuzzy nucleosome architectures). We found that the first (+1) and the last (-last) nucleosomes are contiguous to regions signaled by transcription factor binding sites and unusual DNA physical properties that hinder nucleosome wrapping. Based on these analyses, we developed a method that combines Machine Learning and signal transmission theory able to predict the basal locations of the nucleosomes with an accuracy similar to that of experimental MNase-seqbased methods.

Food day-trippers’ perceptions of regional food destination attractiveness: an application of distance decay theory

ABSTRACT The shift towards local food consumption is creating new opportunities for regional food destinations. The growing market segment of ‘food day-trippers’ who travel to nearby destinations to experience local cuisine has elevated this trend. In response, destination marketers increasingly use local cuisine to enhance destination attractiveness and to create regional food hubs. Yet, it is unclear what attracts food day-trippers to these destinations. This paper explores destination attributes that represent regional food destination attractiveness and presents personal values that shape those attribute preferences. The Repertory Test and Laddering Analysis explore these connections, providing valuable insights into perceptual orientations influencing travel choices within this context. Supported by distance decay theory, findings show that despite the common proposition prioritising food-related attributes in food destination marketing, proximity and non-food attributes also appear important. Underlined by personal values such as a sense of security, these attribute preferences demonstrate food day-trippers’ tendency to look for novelty in food experiences rather than in the location. Practically, these insights highlight an opportunity to capitalise on repeat visitation and aid destination marketers in revisiting their value propositions to include elements that go beyond food.

Critical Examination of Gamow's Theory of Alpha Particle Decay

Gamow’s Theory of Alpha Particle Decay was initially formulated for a limited set of nuclei. In this study, the researchers extend the scope and assessed the applicability of the theory to a broader range of nuclides especially those with different proton and neutron compositions. Three objectives were formulated to undertake the research. The researcher utilized one-dimensional WKB approximation to calculate the probability of tunneling through the potential barrier, which is a simplification compared to other formulas. The Geiger-Nuttall law, which describes a dependence of the disintegration constant on the range of α-particles, was deduced using the Gamow theory describing the passage of the α-particles through the Coulomb barrier by the quantum mechanical tunneling effect. Ground-to-ground state α-transitions for α-active nuclides were analyzed based on their half-lives and their dependence on various factors. The study revealed that all α-active nuclides whose Z ranges between 70 to100 undergoes similar alpha decay processes.

Impact of Urban Air Quality on Total Factor Productivity: Empirical Insights from Chinese Listed Companies

Urban air quality is inextricably linked to the operations of micro-firms. This paper employs the “Qinling-Huaihe” River demarcation as an instrumental variable to construct a regression discontinuity design (RDD) coupled with the two-stage least squares (2SLS) approach. This methodological framework is utilized to investigate the influence of urban air quality on the corporate total factor productivity (CTFP) of publicly listed manufacturing firms from 2015 to 2020. Drawing on the broken windows theory of urban decay and the general equilibrium theory, this research elucidates a significant adverse effect of urban air pollution on CTFP. We rigorously confirm the validity of the RDD by conducting covariate continuity tests and manipulating distributional variables. Furthermore, the robustness of the baseline regression outcomes is substantiated through a series of sensitivity, robustness, and endogeneity checks, employing alternative instrumental variables. The analysis extends to examining the heterogeneity across environmental attributes, regional features, and green branding. The mechanistic investigation reveals that public environmental concerns, financing constraints, and investments in technological innovation serve as mediators in the nexus between urban air pollution and CTFP. Additionally, it is observed that environmental regulation exerts a positive moderating influence, whereas female leadership has a negative impact in this context. The imperative for timely environmental governance is underscored by these findings, which offer crucial insights for policymakers seeking to refine business environment strategies and for corporations aiming to pursue sustainable growth.

Modeling of primary breakup considering turbulent nozzle flow, internal turbulence and surface instability of liquid jet using turbulence decay theory

In heat engines utilizing fuel injection, the processes of atomization and spray formation have a significant impact on the combustion process, thereby determining both efficiency and emission characteristics. Accurate prediction and control of spray formation in fuel injection systems play a key role in improving the efficiency and environmental performance of thermal engines, especially with the emergence of carbon-neutral fuels. To achieve accurate prediction of spray mixture formation, it is imperative to refine the atomization model for the liquid jet within numerical simulations. This requires a phenomenological representation of the atomization process that avoids reliance on computational constants obtained from spray experimental results. Consequently, the present study attempts to mathematically model the turbulent nozzle flow and liquid jet atomization process, leading to the development of a novel primary breakup model. The construction of the primary breakup model involves an analysis of the turbulence at the nozzle inlet. By merging this turbulence with the turbulence resulting from wall shear flow within the nozzle, the model provides insight into the internal turbulence and surface instability of the liquid jet, encompassing the turbulence spectrum. Consequently, the influence of nozzle length on the turbulent flow within the nozzle can be understood, and the droplet formation characteristics of the liquid jet can be predicted along with its multi-wavelength dispersion characteristics. The model effectively captures the experimental results in terms of breakup length and droplet dispersion characteristics, thus adding a higher level of accuracy to numerical simulations. Ultimately, the in-depth study of this model, coupled with its comparison with experimental results, enhances the understanding of the liquid jet atomization process.

Prompt-fission observable and fission yield calculations for actinides by TALYS

The nuclear reaction code TALYS adopts the Hauser-Feshbach statistical decay theory, to de-excite fission fragments. This involves for instance the evaporation of prompt fission neutrons and γ-rays. TALYS incorporates databases of primary fission fragment distribution which consists of primary fission fragment yield and data for excitation energy distribution of fission fragments. We conducted a sensitivity study on three parameters in TALYS and fitted them in order to reproduce experimental and evaluated data, in thermal neutron-induced fission of 235U. Moreover, we demonstrate a large-scale calculation of average prompt neutron and γ-ray multiplicities for 243 selected actinide isotopes.

The Standard Model Theory of Neutron Beta Decay

We review the status of the Standard Model theory of neutron beta decay. Particular emphasis is put on the recent developments in the electroweak radiative corrections. Given that some existing approaches give slightly different results, we thoroughly review the origin of discrepancies, and provide our recommended value for the radiative correction to the neutron and nuclear decay rates. The use of dispersion relation, lattice Quantum Chromodynamics, and an effective field theory framework allows for high-precision theory calculations at the level of 10−4, turning neutron beta decay into a powerful tool to search for new physics, complementary to high-energy collider experiments. We offer an outlook to the future improvements.

Probing the Internal Physics of Neutron Stars through the Observed Braking Indices and Magnetic Tilt Angles of Several Young Pulsars

The braking indices of pulsars may contain important information about the internal physics of neutron stars (NSs), such as neutron superfluidity and internal magnetic fields. As a subsequent paper of Cheng et al., we perform the same analysis as that done in the previous paper to other young pulsars with a steady braking index, n. Combining the timing data of these pulsars with the theory of magnetic field decay, and using their measured magnetic tilt angles, we can set constraints on the number of precession cycles, ξ, which represents the interactions between superfluid neutrons and other particles in the NS interior. For the pulsars considered in this paper, the results show that ξ is within the range of a few ×103 to a few ×106. Interestingly, for the Crab and Vela pulsars, the constraints on ξ obtained with our method are generally consistent with that derived from modeling of the glitch rise behaviors of the two pulsars. Furthermore, we find that the internal magnetic fields of pulsar with n < 3 may be dominated by the toroidal components. Our results may not only help to understand the interactions between the superfluid neutrons and other particles in the interior of NSs but also be important for the study of continuous gravitational waves from pulsars.

Bubble nucleation at zero and nonzero temperatures

The theory of false vacuum decay in a thermal system may have a cross-over from predominantly thermal transitions to quantum transitions as the temperature is decreased. New numerical methods and results are presented here that can be used to model thermal and vacuum bubble nucleation in this regime for cosmology and for laboratory analogues of early universe phase transitions.

Will to Power as an Ontological Principle and as a Theory of Decay

Resumo: O artigo propõe uma nova leitura da “Wille zur Macht” na obra de Nietzsche, buscando por suas premissas nos primeiros escritos, tanto quanto as primeiras ocorrências nos textos e nos fragmentos póstumos, e sublinhando o sentido que gradualmente adquire, com particular atenção à obra, desenhada e nunca construída, que se pretendia dedicar a esse conceito. A reconstrução filológica e filosófica permite destacar o significado estratégico da “vontade de potência” para o pensamento de Nietzsche, que, com a Genealogia da Moral e O Anticristo, através da crítica da metafísica, culmina numa teoria radical da decadência.

What drives willingness to travel in the context of COVID-19?—A measurement of eco-environmental values

The outbreak of COVID-19 has had tremendous impacts on human health and the world economy. Studies have focused on the impact of COVID-19 on potential tourists and tourism destinations from the perspectives of individuals, industries and organizations, and they have provided some measures for tourism recovery. However, under the situation of individual restriction, research has not systematically explained residents’ desire for trips of different distances and factors or the similarities and differences in the factors affecting tourism willingness for trips of different distances. In this context, a measurement of eco-environmental values is used to investigate these issues to help the tourism economy recover. Using online questionnaires covering all provinces in mainland China, this paper investigates residents’ travel willingness to make trips of different distances, and it utilizes binary logistic regression analysis to examine the factors that help predict tourists’ travel intentions. In addition, the patterns of willingness to travel different distances are displayed in maps generated by ArcGIS software. The results suggest that the objective COVID-19 confirmed case distribution follows distance decay theory; however, the distribution patterns of travel willingness are not in accordance with distance decay. The factors that have a significant impact on predicting travel willingness regarding the three kinds of trip distances are educational background, cognition of COVID-19, and geographical division factors. Income and the severity of the pandemic situation play different roles in predicting travel willingness in this study. Overall, the findings of this study extend the application of distance decay theory, which contributes to tourism studies in the COVID-19 context. The findings are also beneficial for tourism recovery and crisis management against the backdrop of pandemic normalization.

A partitioned model for predicting the spatial development of flow in ecological vegetated rivers with submerged vegetation

The evolution of the velocity caused by submerged vegetation in river courses with regular cross sections has been poorly investigated using analytical methods. Fully understanding the longitudinal profiles of the velocity is significant and essential to study the hydrodynamic processes taking place in wetland ecosystems, which is the most important indicator of energy transfer and material exchange in fluvial ecosystems. Based on the experimental data in the literature, the streamwise velocity gradually is found to decrease in the submerged vegetation and increase in the free surface layer. A four-panel analytical model derived from exponential decay theory was developed to predict the streamwise velocity occurring both upstream and within vegetation along the main flow direction in a rectangular open channel with a submerged vegetation patch. We aim at the development of velocity, which is averaged across the vegetation and free surface layers separately, and the length scales shown in the velocity evolution. The explicit calculation expression for each parameter in the analytical model was provided, and sensitivity analysis was conducted by changing the parameters to check how the predicted velocity changed. The change in the drag coefficient of vegetation (CD) and the velocity at the leading edge of the vegetation (U0) influenced the development of velocity. The former mainly enlarges the velocity difference between the vegetation and free surface layers after the leading edge as it increases, and the latter mainly diminishes the velocity difference before the leading edge as it increases. The error statistics is conducted and shows that the predicted and measured velocities are consistent within a relative error of 11%, indicating that the partitioned model is applicable in predicting longitudinal velocity in flows with submerged vegetation of various flexibility. The theoretical analysis of velocity development paves the way for the future studies on the flow turbulent structure and sediment transport in partially vegetated rivers.

Examining the importance of spatial aspects of travel routes: A multi-method approach

A well-designed travel route can increase tourists’ satisfaction and revisit intentions by helping them explore popular or/and hidden places conveniently and thus better experiencing the destination. The popularity of travel route development has resulted in tourists using cities’ infrastructure to enable travel from areas with well-structured accessibility to more inaccessible areas. Despite the importance of the accessibility of travel routes to enhance travel experiences, the tourism literature lacks an understanding of how travel routes should consider not only the physical distance between tourist destinations but also accessibility using mobility within smart tourism cities. Therefore, this research aims to examine the importance of considering accessibility in assessing a travel route. Drawing on the distance decay theory and the concept of the effective tourism exclusion zone (ETEZ), we argue that a travel route can be adopted when every part of the route is accessible in terms of time cost. To achieve the objective, this research adopted a multi-method approach. We explored how much developers consider accessibility when generating a travel route via a case study in study 1. An experiment, study 2, strengthened the results of study 1, presenting cause-and-effect relationships. This study provides theoretical and practical implications for developers of travel routes.

Simulation of self-induced capillary break up of a viscous liquid jet

The aim of the study is to reveal the patterns of self-induced disintegration of a viscous liquid jet flowing out at low speed from a capillary hole under microgravity conditions. The research method is numerical modeling of the regularities of self-induced capillary decay using the methods of Lagrange mechanics. Results. A verified technique for numerical simulation of a capillary jet of a viscous liquid based on the methods of Lagrange mechanics. Identified patterns of self-induced decay of a viscous jet under microgravity conditions. Dependence of the length of the undisintegrated part of the jet on the viscosity of the liquid and the velocity of its outflow from the capillary nozzle. Conclusion. The developed numerical simulation technique allows one to correctly and efficiently (from the point of view of the computing resource used) simulate the dynamics of a capillary jet, taking into account complex nonlinear and boundary effects. A pronounced effect of viscosity on the regularities of the disintegration of a jet moving at low speed has been established. The obtained spectral characteristics of perturbations in the jet make it possible to raise the question of the possibility of developing an asymptotic theory of the self-induced decay of a viscous jet.

Existence of Equistable Quasi-Microphases in Degenerate Silicon: Revelation through an Atypical Thermal Response of the Fano–Raman Parameter

Temperature-induced quasi-phase transition in degenerate crystalline silicon has been studied using temperature-dependent Raman spectroscopy. Atypical temperature dependence of Raman spectral width has been observed, which shows a parabolic nature, making it inconsistent with the existing anharmonic phonon decay theory. This has been analyzed by considering the presence of multiple phonon decay pathways, which depend differently under thermal stimuli. The data have been analyzed to explore the possibility of the existence of quasi-microphases and their reversible temperature-induced phase transition. Thermal hysteresis has been investigated to understand the phase stability and relative activation energy. A theoretical model has been developed to explain the parabolic nature of the Raman width vs temperature curve, showing a good agreement between the two. Temperature-dependent coupling parameters for electron–phonon interactions have been calculated, which confirm the existence of quasi-microscopic temperature-induced phases. The comprehensive analysis of the temperature-dependent variation of Raman parameters and developed theoretical model thereafter may be useful in understanding temperature-dependent electrical properties in electronic-grade doped semiconductors.

Constraints on Sterile Neutrino Models from Strong Gravitational Lensing, MilkyWay Satellites, and the Lyman-α Forest.

The nature of dark matter is one of the most important unsolved questions in science. Some darkf matter candidates do not have sufficient nongravitational interactions to be probed in laboratory or accelerator experiments. It is thus important to develop astrophysical probes which can constrain or lead to a discovery of such candidates. We illustrate this using state-of-the-art measurements of strong gravitationally lensed quasars to constrain four of the most popular sterile neutrino models, and also report the constraints for other independent methods that are comparable in procedure. First, we derive effective relations to describe the correspondence between the mass of a thermal relic warm dark matter particle and the mass of sterile neutrinos produced via Higgs decay and grand unified theory (GUT)-scale scenarios, in terms of large-scale structure and galaxy formation astrophysical effects. Second, we show that sterile neutrinos produced through the Higgs decay mechanism are allowed only for mass >26 keV, and GUT-scale scenario >5.3 keV. Third, we show that the single sterile neutrino model produced through active neutrino oscillations is allowed for mass >92 keV, and the three sterile neutrino minimal standard model (νMSM) for mass >16 keV. These are the most stringent experimental limits on these models.

Precise Q -value measurements of Ag112,113 and Cd115 with the Canadian Penning trap for evaluation of potential ultralow Q -value β decays

An ultra-low Q value $\beta$-decay can occur from a parent nuclide to an excited state in the daughter with $Q_{UL}$ <1 keV. These decays are of interest for nuclear $\beta$-decay theory and as potential candidates in neutrino mass determination experiments. To date, only one ultra-low Q value $\beta$-decay has been observed -- that of $^{115}$In with $Q_\beta$ = 147(10) eV. A number of other potential candidates exist, but improved mass measurements are necessary to determine if the decays are energetically allowed and, in fact, ultra-low. We performed precise $\beta$-decay Q value measurements of $^{112,113}$Ag and $^{115}$Cd and combined them with nuclear energy level data for the daughter isotopes to determine if the potential UL Q value $\beta$-decay branches of $^{112,113}$Ag and $^{115}$Cd are energetically allowed and <1 keV. The Canadian Penning Trap at ANL was used to measure the cyclotron frequency ratios of singly-charged $^{112,113}$Ag and $^{115}$Cd ions with respect to their daughters. From these measurements, the ground-state $\beta$-decay Q values were obtained. The $^{112}$Ag, $^{113}$Ag, and $^{115}$Cd $\beta$-decay Q values were measured to be 3990.16(22) keV, 2085.7(4.6) keV, and 1451.36(34) keV, respectively. These results were compared to energies of excited states in $^{112}$Cd at 3997.75(14) keV, $^{113}$Cd at 2015.6(2.5) and 2080(10) keV, and $^{115}$In at 1448.787(9) keV, resulting in $Q_{\textrm{UL}}$ values of --7.59(26) keV, 6(11) keV, and 2.57(34) keV, respectively. The potential UL Q value decays of $^{112}$Ag and $^{115}$Cd have been ruled out. $^{113}$Ag is still a possible candidate until a more precise measurement of the 2080(10) keV, 1/2$^{+}$ state of $^{113}$Cd is available. In the course of this work we have found the ground state mass of $^{113}$Ag reported in the 2020AME to be lower than our measurement by 69(17) keV (a 4$\sigma$ discrepancy).

Identification of mixing water source and response mechanism of radium and radon under mining in limestone of coal seam floor

With the gradual increase of the coal mining depth, the mixing of multiple water sources intensifies and the activity of radium and radon in groundwater increases. Identifying the source of mine water inrush by using radium and radon isotopes is a new choice. In this paper, the mathematical statistics method, radioactive isotope decay theory, the mass conservation principle, and the numerical simulation method are used to analyze the influence of total dissolved solids (TDS), pH, and the hydrochemical ion content in groundwater on the isotope activity of radium, radon, uranium, thorium, and lead. The activity of thorium and lead is lower than the detection limit of the instrument, and the influence of coal mining activities on it is small. The simulation of the radium–radon mass balance in groundwater shows that the greater the adsorption coefficient (k) of solid particles in groundwater is, the more obvious the adsorption effect and the greater the influence on the radium–radon activity balance are. The radium–radon dating method is used to calculate the groundwater age. Results show that the groundwater age in the closed pit coal mining area is generally older than that in the mining coal mining area. Combined with the 222Rn, 226Ra, and 234U radioactive isotopes and temperature, a mixing water source identification model of limestone in the coal seam floor is constructed. The model shows that the radium activity and temperature of the groundwater are inversely proportional to the mixing ratio of the Permian sandstone water. From the closed pit coal mining area to the mining coal mining area, the radium radon activity of the groundwater increases gradually, the groundwater age decreases significantly, the water cycle is accelerated, the mixing ratio of the Permian sandstone water decreases gradually, the mixing ratio of the Ordovician limestone water increases gradually, and the risk of coal mine water inrush increases. The research results prove the feasibility of the new method for accurately discriminating the mixing water sources in coal mine areas, which is of great significance to the improvement of the theory of coal mine water disaster prevention and control.

Internal vortex breakdowns with stair-step change in rotating flows

Understanding internal vortex breakdowns (VBs) and their trajectories in sealed cylinders are important for the scientific and industrial applications with which they are linked. However, the fluids in sealed cylinders are often sheared, which makes it difficult to clearly and multidirectionally observe their internal flow patterns simultaneously with existing experimental tools; this results in some important features not being captured. In this work, we performed thousands of numerical simulations in a sealed cylinder utilizing the finite element approach. Abundant internal VB patterns were obtained for different aspect ratios as the Reynolds number (Re) increased. To further quantitatively study the morphological evolution of VBs, we focused on the axial lengths and trajectories of VBs with multiple aspect ratios. Surprisingly, the numbers of VBs in the rotating fluid were not fixed for the same aspect ratio, which also affected the complexity of the VB evolution. In particular, the stair-step changes of the locations of the VB and local extrema of the axial velocity, pressure, and vorticity of the key flows at the axis were revealed in detail. We used the theory of swirl decay to explain the VB formation and stair-step change from an energy perspective and clarified why the pressure minimum was under the center of the VB. The discovery of the stair-step change of the VB provided evidence of the existence of a new class of fluid behavior that may provide insight into vortex control.

Weak process for Iron isotopes chain used as seed for heavy elements nucleosynthesis

The weak processes are a key to understand the nucleosynthesis of heavy elements in the universe. In this work we have studied weak processes such as β-decay and neutrino capture that are very important for the r-process. This process takes place in a region between neutron drip and β-stability line. For nuclei far from β-stability line the experimental data are very scarce. To study the nucleosynthesis of heavy elements in astrophysics sites like Binary Neutron Star merger (BNS) and Supernova explosions, we have employed the Gross Theory of Beta Decay (GTBD) to evaluate the neutrino-nucleus cross sections and β-decay half-lives. Our 56Fe(νe , e −)56Co cross section show a excelent agreement with microscopic models and the half-lives well reproduce the experimental data with a satisfactory accuracy. We have fitted the neutrino-nucleus cross sections obtained by GTBD using a four degree polynomial dependence of the incident neutrino energy. This dependence allows us to systematically calculate the neutrino-nucleus cross sections for a large amount of nuclei, as occurs in the r-process nucleosynthesis calculation (more than 4000 nuclei). Our fitting and interpolation procedures are shown to be in a good agreement and the GTBD cross sections are successfully reproduced.