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With the rapid development of high performance computers and computational methods, including software, an increasing number of experimental chemists have tried to use computational methods such as optical rotation (OR, including the matrix model), optical rotatory dispersion (ORD), electronic circular dichroism (ECD or CD), vibrational circular dichroism (VCD), and magnetic shielding constants--nuclear magnetic resonance (NMR)--to explain and/or assign absolute configuration (AC) for various compounds. Such reports in the field of natural products have increased dramatically. However, every method has its range of application. This leads, in some cases, to incorrect conclusions by researchers who are not familiar with these methods. In this review, we provide experimental chemists and researchers with more computational details and suitable suggestions, and especially hope that this experience may help readers avoid computational pitfalls. Finally, we discuss the use of simplified models to replace original complex structures with a long side chain. The fundamental basis for using models to represent complex chiral compounds, such as in OR calculations, is the existence of conformation pairs with near canceling conformer contributions that justify the use of models rather than the original compounds. Using examples, we here introduce the transition state (TS) calculation, which may benefit readers in this area for use and mastery for their AC study. This review will summarize the general concepts involved in the study of AC determinations. [ABSTRACT FROM AUTHOR]

We present the main demographic parameters of the Western Siberian pied flycatcher population, nesting in natural habitats, at different stages of population dynamics. The average values, range, boundaries, and direction of changes in the survival of sexually mature individuals, fecundity, and the encounter probability at different ages were analyzed. Using matrix models of population structure and population dynamics, an estimate of the true survival rate of fledglings is given. The range of values of demographic parameters that characterize viable groups of the studied bird species is indicated. [ABSTRACT FROM AUTHOR]

Integrated energy systems (IESs) can easily accommodate renewable energy resources (RESs) and improve the utilization efficiency of fossil energy by integrating various energy production, conversion, and storage technologies. However, the coupled multi-energy flows and the uncertainty of RESs bring challenges regarding optimal scheduling. Therefore, this study proposes an energy bus-based matrix-modeling method and a coordinated scheduling strategy for the IES. The matrix-modeling method can be used to formulate the steady- and transient-state balances of the multi-energy flows, and the transient model can clearly express the multi-time-scale characteristics of the different energy flows. The model parameters are fitted with data from experiments and the literature. To address the inherent randomness of the RESs and loads, a coordinated scheduling strategy is designed that contains two components: day-ahead optimization and rolling optimization. Day-ahead optimization uses the system steady-state model and multiple scenarios from the RES and load forecast data to minimize the operation cost while rolling optimization is based on the system's transient-state model and aims to achieve the optimal real-time scheduling of the energy flows. Finally, a case study is conducted to verify the advantages and effectiveness of the proposed model and optimization method. The results show that stochastic optimization reduces the total daily cost by 1.48% compared to deterministic optimization when considering the prediction errors associated with the RESs and loads, highlighting the stronger adaptability of stochastic optimization to prediction errors. Moreover, rolling optimization based on the system's transient-state model can reduce the errors between day-ahead scheduling and rolling correction. [ABSTRACT FROM AUTHOR]

In this paper, we construct the super Virasoro algebra with an arbitrary conformal dimension Δ from the generalized ℛ (p , q) -deformed quantum algebra and investigate the ℛ (p , q) -deformed super Virasoro algebra with the particular conformal dimension Δ = 1. Furthermore, we perform the ℛ (p , q) -conformal Virasoro n -algebra, the ℛ (p , q) -conformal super Virasoro n -algebra (n -even) and discuss a toy model for the ℛ (p , q) -conformal Virasoro constraints and ℛ (p , q) -conformal super Virasoro constraints. Besides, we generalized the notion of the ℛ (p , q) -elliptic Hermitian matrix model with an arbitrary conformal dimension Δ. Finally, we deduce relevant particular cases generated by quantum algebras known in the literature. [ABSTRACT FROM AUTHOR]

We study a Hermitian matrix model with a kinetic term given by T r (H Φ 2) , where H is a positive definite Hermitian matrix, similar as in the Kontsevich Matrix model, but with its potential Φ 3 replaced by Φ 4 . We show that its partition function solves an integrable Schrödinger-type equation for a non-interacting N-body Harmonic oscillator system. [ABSTRACT FROM AUTHOR]

A matrix model is considered related to a system describing two identical fermions and one particle of another nature on a lattice, interacting via annihilation and creation operators. The problem of the study of the spectrum of a block operator matrix is reduced to the investigation of the spectrum of block operator matrices of order three with a discrete variable, and the relations for the spectrum, essential spectrum, and point spectrum are established. Two-particle and three-particle branches of the essential spectrum of the block operator matrix are singled out. [ABSTRACT FROM AUTHOR]

We study a real symmetric Φ 4 -matrix model whose kinetic term is given by Tr (E Φ 2) , where E is a positive diagonal matrix without degenerate eigenvalues. We show that the partition function of this matrix model corresponds to a zero-energy solution of a Schrödinger type equation with Calogero–Moser Hamiltonian. A family of differential equations satisfied by the partition function is also obtained from the Virasoro algebra. [ABSTRACT FROM AUTHOR]

One of the most hazardous types of landslide disasters is reservoir landslides. Spatially predicting the probability of these events when the hydroelectric power station is not impounded can provide a foundation for their prevention and management. A reservoir landslide prediction study was conducted using the reservoir of the Baihetan Hydropower Station in Southwest China as the research area. The study applied both the widely used data-driven landslide susceptibility assessment method and the physics-based landslide stability evaluation approach. Additionally, a matrix prediction model based on a combination of the aforementioned techniques was suggested for reservoir landslide prediction. The applicability of the three approaches was assessed based on the findings of a field investigation of reservoir landslides during the initial impoundment period. The results demonstrated that, in the absence of historical reservoir landslide data, the prediction success rate of the susceptibility mapping method was incredibly poor, at only 30.19%. While the stability prediction approach had an 88.68% success rate, its frequency ratio was only 5.22. The approach significantly overpredicted reservoir landslides, according to a study of the prediction results for regions. On the other hand, the frequency ratio of the matrix prediction model, which combines the two approaches, was 2.24 times that of the stability prediction approach. Thus, the matrix prediction model was found to be more reliable than other methods and capable of predicting the vast majority of reservoir landslides with fewer extremely high probability reservoir landslide areas. To further increase the accuracy of reservoir landslide prediction, it is recommended to use the matrix prediction model. [ABSTRACT FROM AUTHOR]

Abstract Background There are many predictions about the progression of natural collapse course of osteonecrosis of the femoral head. Here, we aimed to combine the three classical prediction methods to explore the progression of the natural collapse course. Methods This retrospective study included 127 patients admitted to our hospital from October 2016 to October 2017, in whom the femoral head had not collapsed. Logistic regression analysis was performed to determine the collapse risk factors, and Kaplan–Meier survival curves were used for femoral head survival analysis. The collapse rate of the femoral head was recorded within 5 years based on the matrix model. The specificity of the matrix model was analyzed using the receiver operating characteristic curve. Results A total of 127 patients with a total of 202 hips were included in this study, and 98 hips collapsed during the follow-up period. Multivariate logistics regression analysis showed that the predictive ability of the matrix model was stronger than Association Research Circulation Osseous staging, Japanese Investigation Committee classification, and area (P

Avoiding the undesirable impacts of invasive species requires robustly evaluating the effects of alternative management scenarios. Such evaluations depend on reliable spatio‐temporal projections of changes in the distribution and abundance of the invasive species under different scenarios. However, commonly used modelling approaches are constrained for this purpose because they do not incorporate demographic processes and are seldom validated.We develop a spatially and temporally explicit grid‐based population model for invasive fallow deer Dama dama in Tasmania, Australia, validated against observed distribution and abundance 'targets' using a pattern‐oriented approach. We use this validated model to project the future invasion patterns of deer, including encroachment into areas of high conservation value, under eight harvest and habitat suitability scenarios.Projected population sizes of deer differ greatly depending on harvest and habitat suitability scenarios. Without harvest, the population grows sixfold, from about 80,000 deer in 2019 to over 500,000 by 2100. In contrast, the population stabilises at 32,000–41,000 deer with 25% annual harvest. Abundance in the environmentally sensitive Tasmanian Wilderness World Heritage Area (TWWHA), a region of high conservation value, increases in all scenarios. We identify likely areas in the expanding range of deer where targeted removal should be most effective at minimising deer numbers in the TWWHA.Synthesis and applications: Using a pattern‐oriented model validated with spatio‐temporal data, we show how the future distribution and abundance of invasive fallow deer in Tasmania can be substantially reduced by targeted increases in harvest and prioritising areas for removal around high conservation value regions. Our approach can be used to project likely effects of management interventions on future distributions and abundances for a range of invasive taxa. [ABSTRACT FROM AUTHOR]

We present exactly solvable modifications of the two-matrix Zinn-Justin–Zuber model and write it as a tau function. The grand partition function of these matrix integrals is written as the fermion expectation value. The perturbation theory series is written explicitly in terms of a series in strict partitions. The related string equations are presented. [ABSTRACT FROM AUTHOR]

In this paper, we review the novel connection between a theory of N M2-branes on (C²/ℤ2 x C/ℤ2)/ℤk and a discrete integrable system. Besides the IR duality induced by the Hanany-Witten transitions in the type IIB brane construction, the Fermi gas formalism tells us that the partition function of this theory enjoys a larger discrete symmetry which is the Weyl group W(D5) of D5 = SO(10). The Fermi gas formalism, together with the topological string/spectral theory correspondence and the connection between the integrable systems and the Nekrasov partition functions recently found, further suggests that the grand partition function of this M2-brane partition function satisfies a bilinear difference equation associated with W(D5), called q-deformed Painlevé VI. By using the exact values of the partition functions we identify the explicit expression of the bilinear equations and confirm that these equations are indeed satisfied for higher order in the chemical potential dual to the rank N. This article is based on [1] and [2]. [ABSTRACT FROM AUTHOR]

Evaporators are widely used in industrial processes to produce thermally treated distillate by evaporation with concentration of impurities in the bulk of water. As to their thermal efficiency, multistage flash evaporators (MFEs) belong to one of the most promising types of evaporating equipment, in which the consumption of thermal energy for evaporating water in each stage is compensated for by the recovery of this energy in heating the treated water during the condensation of the produced steam. Improvement of the methods for design and operation of these units on the basis of mathematical models of heat- and mass-transfer processes is an urgent problem facing developers and designers of evaporative equipment. Within the scope of the performed study, a combinatorial model is proposed for calculation of the size distribution of superheated water droplets during evaporation in the low-pressure zone of the dirty compartment of an MFE. A mathematical model was developed of a droplet separator designed to prevent water droplet entrainment and ingress of impurities into the distillate. The flowrates of distillate and treated water and the content of impurities in these flows were calculated for each stage of the evaporation unit, taking into consideration the water droplet entrainment from the dirty compartment. The effect of droplet entrainment in multistage evaporators on the quality of distillate was assessed. An approach has been proposed to the design of multistage evaporators providing the specified process indicator under different operating conditions. This approach can also be used in the construction of regime maps of equipment, implementation of measures to improve the efficiency of equipment, and development of systems for diagnostics of heating surface in the evaporators for proper condition. [ABSTRACT FROM AUTHOR]

Integrated energy systems (IESs) can easily accommodate renewable energy resources (RESs) and improve the utilization efficiency of fossil energy by integrating various energy production, conversion, and storage technologies. However, the coupled multi-energy flows and the uncertainty of RESs bring challenges regarding optimal scheduling. Therefore, this study proposes an energy bus-based matrix-modeling method and a coordinated scheduling strategy for the IES. The matrix-modeling method can be used to formulate the steady- and transient-state balances of the multi-energy flows, and the transient model can clearly express the multi-time-scale characteristics of the different energy flows. The model parameters are fitted with data from experiments and the literature. To address the inherent randomness of the RESs and loads, a coordinated scheduling strategy is designed that contains two components: day-ahead optimization and rolling optimization. Day-ahead optimization uses the system steady-state model and multiple scenarios from the RES and load forecast data to minimize the operation cost while rolling optimization is based on the system’s transient-state model and aims to achieve the optimal real-time scheduling of the energy flows. Finally, a case study is conducted to verify the advantages and effectiveness of the proposed model and optimization method. The results show that stochastic optimization reduces the total daily cost by 1.48% compared to deterministic optimization when considering the prediction errors associated with the RESs and loads, highlighting the stronger adaptability of stochastic optimization to prediction errors. Moreover, rolling optimization based on the system’s transient-state model can reduce the errors between day-ahead scheduling and rolling correction.

Political and economic initiatives intended to increase energy production while reducing carbon emissions are driving demand for solar energy. Consequently, desert regions are now targeted for development of large-scale photovoltaic solar energy facilities. Where vegetation communities are left intact or restored within facilities, ground-mounted infrastructure may have negative impacts on desert-adapted plants because it creates novel rainfall runoff and shade conditions. We used experimental solar arrays in the Mojave Desert to test how these altered conditions affect population dynamics for a closely related pair of native annual plants: rare Eriophyllum mohavense and common E. wallacei. We estimated aboveground demographic rates (seedling emergence, survivorship, and fecundity) over 7 yr and used seed bank survival rates from a concurrent study to build matrix models of population growth in three experimental microhabitats. In drier years, shade tended to reduce survival of the common species, but increase survival of the rare species. In a wet year, runoff from panels tended to increase seed output for both species. Population growth projections from microhabitat-specific matrix models showed stronger effects of microhabitat under wetter conditions, and relatively little effect under dry conditions (lack of rainfall was an overwhelming constraint). Performance patterns across microhabitats in the wettest year differed between rare and common species. Projected growth of E. mohavense was substantially reduced in shade, mediated by negative effects on aboveground demographic rates. Hence, the rare species were more susceptible to negative effects of panel infrastructure in wet years that are critical to seed bank replenishment. Our results suggest that altered shade and water runoff regimes associated with energy infrastructure will have differential effects on demographic transitions across annual species and drive population-level processes that determine local abundance, resilience, and persistence.

China’s e-commerce market size, the most active and best-developed component of the digital economy, has become an essential driver of economic growth and urban entrepreneurial activity. This paper analyzes e-commerce development and urban entrepreneurial activity through BCG matrix. It establishes the framework of AHP-SWOT hierarchical analysis model combining with SWOT matrix model and AHP hierarchical analysis. In the development of e-commerce, the national e-commerce turnover in 2020 is 37.21 trillion yuan, with a year-on-year growth rate of 57.60% in 2014. Meanwhile, in 2020, the number of e-commerce employees reaches 60 million, which is 1.23 times of the number in 2014. Due to the rapid development of the economy and e-commerce, resulting in urban entrepreneurial activity is also gradually rising, the number of private enterprises in 2012 grew from 5254870 to 18921928 in 2020, an increase of up to 260%. 2020, the number of new market entities is 27,495,700, the country’s entrepreneurial activity is a year-on-year upward trend. Through the development of e-commerce and urban entrepreneurial activity, the quality of employment and entrepreneurship in society is promoted to a higher level.

This paper firstly analyzes the developmental problems of the construction of the sports course ideology and politics in colleges and universities, starting from the value function of the construction of the sports course ideology and politics. Secondly, it constructs the evaluation index system for the construction of college sports course ideology and politics, utilizes the subordinate criterion function of the subordinate matrix model for the weight calculation of the index subordinate coefficients, and calculates the positive and negative ideal solutions and relative posting progress of each index through the TOPSIS method. Finally, in order to analyze the transformation of the number-based effectiveness of the construction of the college sports course ideology and politics, an example verification analysis was carried out. The results show that the transformation of digital effectiveness in the construction of the ideology and politics of sports courses in colleges and universities is mainly carried out through the shaping of students’ values, the cultivation of ideals and beliefs, and the analysis of the weights of the indexes points out the direction of the development of the construction of ideology and politics of sports courses. This shows that the transformation of the digital effectiveness of the ideological and political construction of physical education courses needs to start from the spirit of sports, which in turn promotes the ideological and political construction of physical education courses to boost the quality of physical education disciplines.

In this paper, firstly, on the basis of the digital construction of the Civics course, we propose to construct a Civics course teaching system to realize the transformation of digital type effectiveness of the Civics course and design the functional module and database module of Civics course teaching system according to the connection between students, teaching content and teachers. Secondly, on the basis of the matrix model, the subordination degree function of the Civics course is determined according to the subordination relationship of the Civics course features, and then the contribution degree of the variable factors of the Civics course is calculated by using the segmented subordination function, and the contribution degree of each factor is combined to construct the matrix model of the Civics course teaching system. Then, set the set of evaluation factors of the course Civics teaching system, calculate the evaluation factor scores of the Civics teaching system by using the multi-factor synthesis method, and evaluate and analyze the digital construction of Civics courses in colleges and universities. The results show that on the matrix model, the comprehensive score of Chengdu University’s curriculum Civics system construction is calculated to be 88, which also verifies that the teaching system of Civics courses runs well. On the sense of teacher efficacy, the significant probability value of P less than 0.05 for teaching age, title, and education indicates a significant relationship with the sense of teacher efficacy.

This paper achieves high-quality sharing of preschool educational resources among learners based on a matrix model. Through the shared resource matrix analysis method, the symmetry of the matrix about this educational resource is judged so that the resource can transmit information implicitly among all subjects. The difference between noise and preschool education resource data points is enhanced using the K-nearest neighbor search algorithm. Combined with the ant colony particle swarm optimization algorithm, the sharing sequence and time of the optimal preschool education resources are calculated, and a preschool education resource-sharing platform is constructed. To verify the applicability of the constructed platform, the simulation analysis results show that the resource search accuracy of the platform constructed in this paper reaches 94.51% on average, and the compatibility performance index is as high as 7.287vw, which is 3.25vw and 3.421vw higher compared to other platforms, respectively. The results show that the matrix model can eliminate resource heterogeneity and provide convenient and efficient interactive technical support for constructing a preschool education resource-sharing platform.

In this paper, based on the matrix model to count the number of elements and judge the symmetry of matrix elements, the nearest neighbor space in high-dimensional space is converted into a symmetry matrix. The boundary extraction is discretized and iterated repeatedly until the fitness satisfies the final condition. The genetic algorithm finds the optimal solution, which is transformed into the fitness function, and the system reliability constraints are processed to solve the cost control problem. According to the results, the cost control cost of the construction project is reduced by 10% based on the matrix model. It shows that the proposed model can promptly solve the existing project cost over-budget situation, which makes the enterprise obtain more economic benefits and enhance the market’s competitiveness.

The ecosystem services framework is a convenient approach for identifying and mapping nature's contributions to people, and an accurate assessment of ecosystem services potential is the first step in the decision support process of well-informed land management planning. The approach we use for forest ecosystem services potential assessment in Latvia is based on the principles of the matrix model and biophysical data of the forest inventory database, and it is comparable to other assessments previously carried out in the Baltic Sea Region. The proposed approach supports spatial planning and may be integrated with assessments of other ecosystems based on the same methodological principles. The evaluation results reflect the high spatial heterogeneity of forest types in Latvia. Future work should include integrating ecosystem services flows and demand into the assessment, developing additional indicators for culturally important ecosystem services, and introducing socio-cultural valuation to account for a broader set of stakeholders and values. [ABSTRACT FROM AUTHOR]

The effect of ball size and interstitial filling on the performance of dry ball mill grinding was investigated for a limestone-type brecciated uranium ore. The optimum grinding was obtained with the combination of different balls (12.7–37.5 mm) and interstitial filling of 50% (20% ball filling ratio at fixed material filling ratio = 4%). The net power consumption in a ball mill is proportional to the specific rate of breakage. A mathematical relation for the specific rate of breakage as a function of ball filling ratio was developed. The grinding process was modeled by the combined use of matrix and population balance model. The cumbersome method of mono-size fraction in the determination of the selection function was avoided, and instead, it was determined by the back-calculation method. The estimated parameters of the Austin selection function for a particular ball size (31.7 mm) were successfully applied in predicting the ground product size distribution (R2 > 0.95) for both a given feed size distribution and a given feed rate. [ABSTRACT FROM AUTHOR]

Using a suitably noncommutative flat matrix model, it is shown that the quantum permutation group has free orbitals: that is, a monomial in the generators of the algebra of functions can be zero for trivial reasons only. It is shown that any strictly intermediate quantum subgroup between the classical and quantum permutation groups must have free three-orbitals, and this is used to derive some elementary bounds for the Haar state on degree four monomials in such quantum permutation groups. Exploiting the main character, explicit formulae are given in the case of the quantum permutation group. [ABSTRACT FROM AUTHOR]

We review a cosmological model where the metric determinant plays a dynamical role and present new numerical results on the cancellation of the vacuum energy density including the contribution of a cosmological constant. The action of this model is only invariant under restricted coordinate transformations with unit Jacobian (the same restriction appears in the well-known unimodular-gravity approach to the cosmological constant problem). As to the possible origin of the nonstandard terms in the matter action of the model, we show that these terms can, in principle, arise from the emergent gravity in the IIB matrix model, a nonperturbative formulation of superstring theory. [ABSTRACT FROM AUTHOR]

Large across-model spread in simulating land carbon (C) dynamics has been ubiquitously demonstrated in model intercomparison projects (MIPs), and became a major impediment in advancing climate change prediction. Thus, it is imperative to identify underlying sources of the spread. Here, we used a novel matrix approach to analytically pin down the sources of across-model spread in transient peatland C dynamics in response to a factorial combination of two atmospheric CO2 levels and five temperature levels. We developed a matrix-based MIP by converting the C cycle module of eight land models (i.e., TEM, CENTURY4, DALEC2, TECO, FBDC, CASA, CLM4.5 and ORCHIDEE) into eight matrix models. While the model average of ecosystem C storage was comparable to the measurement, the simulation differed largely among models, mainly due to inter-model difference in baseline C residence time. Models generally overestimated net ecosystem production (NEP), with a large spread that was mainly attributed to inter-model difference in environmental scalar. Based on the sources of spreads identified, we sequentially standardized model parameters to shrink simulated ecosystem C storage and NEP to almost none. Models generally captured the observed negative response of NEP to warming, but differed largely in the magnitude of response, due to differences in baseline C residence time and temperature sensitivity of decomposition. While there was a lack of response of NEP to elevated CO2 (eCO2) concentrations in the measurements, simulated NEP responded positively to eCO2 concentrations in most models, due to the positive responses of simulated net primary production. Our study used one case study in Minnesota peatland to demonstrate that the sources of across-model spreads in simulating transient C dynamics can be precisely traced to model structures and parameters, regardless of their complexity, given the protocol that all the matrix models were driven by the same gross primary production and environmental variables. [ABSTRACT FROM AUTHOR]

The role of forests in mitigating climate change by acting as a carbon sink is becoming increasingly important. Forest management practices can either positively or negatively affect the ability of forests to mitigate climate change. The objectives of our study were to: (a) investigate the effects of natural disturbances on long-term carbon sequestration dynamics in forests and (b) identify opportunities to adapt current forest management practices to increase carbon sequestration in forests. The study focused on mixed mountain forests in the Slovenian Alps, dominated by Norway spruce, and used the SLOMATRIX model to simulate forest development. Three forest management scenarios were simulated: (1) no management, (2) business-as-usual and (3) an optimized scenario maximizing carbon sequestration in forests while achieving the required harvest. Our results indicate that both forest management practices and natural disturbances have an impact on carbon sequestration dynamics. Optimizing harvests resulted in changes in the diameter structure and species composition of the harvested trees. Although natural disturbances can hinder the mitigation of climate change impacts, they can also catalyze forest adaptation to climate change and reduce the time required to reach carbon equilibrium. [ABSTRACT FROM AUTHOR]

In clonal plant populations, a number of genetically identical ramets form a genet. While coexisting ramets potentially perform independently, their behaviours not only depend on ages and sizes but are also constrained by genetic background. In this study, genet dynamics and its variability among neighbouring genets were investigated based on the ramet demography of each genet in Convallaria keiskei. Genet dynamics were first formulated as a matrix model with the two components of clonal growth (clonal reproduction) and survival‐transitions between ramet size classes. Then, a statistical estimation of the matrix elements was established using three datasets: aboveground demographic censuses, belowground directional rhizome connections and genetic identification of ramets. Finally, genet growth rates reflecting both the changes of clonal growth and ramet size growth were estimated and compared for fundamental demographic elements among genets. Over three years of aboveground annual censuses of a 28 × 2 m plot, 2021 ramets were identified as belonging to 28 genotypes. Belowground excavation detected 515 clonal fragments. Genet growth rate of three dominant genets varied with medians of 1.13, 1.02 and 1.05; 95% credible intervals of the posterior distributions did not overlap between the genet with the largest median and the others. The variation was caused primarily by differences in clonal growth rather than survival‐transitions between size classes. Clonal growth by branching was rarer than at the tips but contributed to the maintenance of the genet. Therefore, both clonal growth frequencies and connecting patterns of ramets caused the variation of genet dynamics and established genets persist for a long time through the positive growth rates, which would contribute to maintain a population. We also conclude that fundamental demographic elements relating to clonal growth traits (the features of individual genets) strongly impact genet dynamics. [ABSTRACT FROM AUTHOR]

In this paper, provide a survey of recent studies of supergroup gauge theory. We first discuss the supermatrix model as a zero-dimensional toy model of supergroup gauge theory and its geometric and algebraic characterization. We then focus on four-dimensional Yang–Mills theory with supergroup gauge symmetry and explore its nonperturbative properties, including instanton calculus, Seiberg–Witten geometry, Bethe/gauge correspondence, and its realization with intersecting defects. [ABSTRACT FROM AUTHOR]

Predicting temporal dynamics of genetic diversity is important for assessing long-term population persistence. In stage-structured populations, especially in perennial plant species, genetic diversity is often compared among life history stages, such as seedlings, juveniles, and flowerings, using neutral genetic markers. The comparison among stages is sometimes referred to as demographic genetic structure, which has been regarded as a proxy of potential genetic changes because individuals in mature stages will die and be replaced by those in more immature stages over the course of time. However, due to the lack of theoretical examination, the basic property of the stage-wise genetic diversity remained unclear. We developed a matrix model which was made up of difference equations of the probability of non-identical-by-descent of each life history stage at a neutral locus to describe the dynamics and the inter-stage differences of genetic diversity in stage-structured plant populations. Based on the model, we formulated demographic genetic structure as well as the annual change rate of the probability of non-identical-by-descent (denoted as η). We checked if theoretical expectations on demographic genetic structure and η obtained from our model agreed with computational results of stochastic simulation using randomly generated 3,000 life histories. We then examined the relationships of demographic genetic structure with effective population size N e , which is the determinants of diversity loss per generation time. Theoretical expectations on η and demographic genetic structure fitted well to the results of stochastic simulation, supporting the validity of our model. Demographic genetic structure varied independently of N e and η , while having a strong correlation with stable stage distribution: genetic diversity was lower in stages with fewer individuals. Our results indicate that demographic genetic structure strongly reflects stable stage distribution, rather than temporal genetic dynamics, and that inferring future genetic diversity solely from demographic genetic structure would be misleading. Instead of demographic genetic structure, we propose η as an useful tool to predict genetic diversity at the same time scale as population dynamics (i.e., per year), facilitating evaluation on population viability from a genetic point of view. [ABSTRACT FROM AUTHOR]

In this paper we investigate a novel connection between the effective theory of M2-branes on (C 2 / Z 2 × C 2 / Z 2) / Z k and the q -deformed Painlevé equations, by proposing that the grand canonical partition function of the corresponding four-nodes circular quiver N = 4 Chern–Simons matter theory solves the q -Painlevé VI equation. We analyse how this describes the moduli space of the topological string on local dP 5 and, via geometric engineering, five dimensional N f = 4 SU (2) N = 1 gauge theory on a circle. The results we find extend the known relation between ABJM theory, q -Painlevé III 3 , and topological strings on local P 1 × P 1 . From the mathematical viewpoint the quiver Chern–Simons theory provides a conjectural Fredholm determinant realisation of the q -Painlevé VI τ -function. We provide evidence for this proposal by analytic and numerical checks and discuss in detail the successive decoupling limits down to N f = 0 , corresponding to q -Painlevé III 3 . [ABSTRACT FROM AUTHOR]

Active neutral-point-clamped converter adds open-circuit fault-tolerant (OCFT) capability compared with the widely used original neutral-point-clamped (NPC) topology. However, such capability is hard to utilize due to difficulties in pulse-width modulation (PWM) design and the randomness of failure points, particularly in high-level converters. Current research mainly focused on low-level topologies with a limited number of fault scenarios; moreover, the analysis and design are performed in a nonsystematic way. In this article, the OCFT operations of active NPC (ANPC) converters with multiple fault switches are investigated and the systematic PWM design process is proposed. First, different matrices are proposed for the ANPC converters to capture the complicated topology information and achieve an exhaustive analysis of the topological redundancy. Then, a step-by-step process is proposed to derive the suitable OCFT PWM patterns. The five-level ANPC converter is investigated as an example. Its experimental results validate that the proposed approach can 1) properly predict the behavior of converters systematically so that the tolerable faults and intolerable can be identified during the design procedure, and 2) the inherent fault-tolerant capability of the five-level ANPC converter can be guaranteed through the proposed method, and 3) multiswitch open-circuit faults can be easily dealt with by implementing suitable carrier-based PWM schemes. [ABSTRACT FROM AUTHOR]

Models based on national forest inventory (NFI) data intend to project forests under management and policy scenarios. This study aimed at quantifying the influence of NFI sampling uncertainty on parameters and simulations of the demographic model MARGOT. Parameter variance–covariance structure was estimated from bootstrap sampling of NFI field plots. Parameter variances and distributions were further modeled to serve as a plug‐in option to any inventory‐based initial condition. Forty‐year time series of observed forest growing stock were compared with model simulations to balance model uncertainty and bias. Variance models showed high accuracies. The Gamma distribution best fitted the distributions of transition, mortality and felling rates, while the Gaussian distribution best fitted tree recruitment fluxes. Simulation uncertainty amounted to 12% of the model bias at the country scale. Parameter covariance structure increased simulation uncertainty by 5.5% in this 12%. This uncertainty appraisal allows targeting model bias as a modeling priority. Recommendations for Resource Managers: •Uncovering the potential and limitations of large‐scale forest models are needed when deducing recommendations from forest resource projections under forest management and policy scenarios at regional, national, or continental scales.•Estimating simulation uncertainty in these models is crucial to assess their accuracy. The present study offers a generic methodological strategy for assessing parameter uncertainty in large‐scale forest models.•Users of the MARGOT model should consider that simulation uncertainties proved to be low at a national scale, but decennial wood stock increases as observed in the French forests over the period 1970–2016 were underestimated.•Assessing simulation uncertainty is also major for model bias appraisal. Better accounting for the controls of forest demographic processes (growth, regeneration and mortality) appears to be a priority for the development of MARGOT, and for other large‐scale models. [ABSTRACT FROM AUTHOR]

Background: Among species with size structured demography, population structure is determined by size specific survival and growth rates. This interplay is particularly important among recently settled colonial invertebrates for which survival is low and growth is the only way of escaping the high mortality that small colonies are subject to. Gorgonian corals settling on reefs can grow into colonies of millions of polyps and can be meters tall. However, all colonies start their benthic lives as single polyps, which are subject to high mortality rates. Annual survival among these species increases with size, reflecting the ability of colonies to increasingly survive partial mortality as they grow larger. Methods: Data on survival and growth of gorgonian recruits in the genera Eunicea and Pseudoplexaura at two sites on the southern coast of St John, US Virgin Islands were used to generate a stage structured model that characterizes growth of recruits from 0.3 cm until they reach 5 cm height. The model used the frequency distributions of colony growth rates to incorporate variability into the model. Results: High probabilities of zero and negative growth increase the time necessary to reach 5 cm and extends the demographic bottleneck caused by high mortality to multiple years. Only 5% of the recruits in the model survived and reached 5 cm height and, on average, recruits required 3 y to reach 5 cm height. Field measurements of recruitment rates often use colony height to differentiate recruits from older colonies, but height cannot unambiguously identify recruits due to the highly variable nature of colony growth. Our model shows how recruitment rates based on height average recruitment and survival across more than a single year, but size-based definitions of recruitment if consistently used can characterize the role of supply and early survival in the population dynamics of species. [ABSTRACT FROM AUTHOR]

The blue octopus (Octopus cyanea) fishery off the southwest coast of Madagascar is important for coastal communities. This fishery is a key economic resource for the local community as blue octopus catch is sold by local fishers to international and local export markets. Thus, it is important to monitor and evaluate the status of octopus to ensure its sustainability. One common octopus management approach is through the use of temporary spatial closures. Models can be a useful support tool to evaluate the status of a population and assess different possible management strategies. To better understand the biology and assess the sustainability of blue octopus, we parameterize a Levkovitch population matrix model using existing catch data. We found that the octopus population was experiencing a 1.8% decline per month at the time of data collection in 2006. However, since 2006, a number of management practices, including temporary closures lasting several weeks to several months have been implemented successfully. In line with these efforts, our model indicates that the fishery has likely been sustained since 2006 due to these annual closures. Our model provides support to the idea that temporary closures have restored this population and that temporary closures provide flexibility in management strategies that local communities can tailor to their economic and social needs. In addition, we were able to estimate several important life history metrics, such as time in each stage, stable stage distribution, reproductive value, and per stage survivability, that can be used in future work. Collectively, our study provides insight into the biology of blue octopus as well as demonstrate how temporary closures can be an effective conservation strategy due to the wide range of implementation options. [ABSTRACT FROM AUTHOR]

The ecosystem services framework is a convenient approach for identifying and mapping nature’s contributions to people, and an accurate assessment of ecosystem services potential is the first step in the decision support process of well-informed land management planning. The approach we use for forest ecosystem services potential assessment in Latvia is based on the principles of the matrix model and biophysical data of the forest inventory database, and it is comparable to other assessments previously carried out in the Baltic Sea Region. The proposed approach supports spatial planning and may be integrated with assessments of other ecosystems based on the same methodological principles. The evaluation results reflect the high spatial heterogeneity of forest types in Latvia. Future work should include integrating ecosystem services flows and demand into the assessment, developing additional indicators for culturally important ecosystem services, and introducing socio-cultural valuation to account for a broader set of stakeholders and values.

Abstract Background The Philippines has been severely affected by the methamphetamine crisis. The government has launched a policy war against drug use, although the severe sanctions imposed on drug users have been criticized internationally. To help implement a more effective and humane approach to drug use, this study aimed to introduce a comprehensive treatment program for methamphetamine users based on cognitive-behavioral therapy (CBT) whose effectiveness will be evaluated through a randomized controlled trial. Methods Methamphetamine users admitted into government-run rehabilitation facilities are recruited and randomly assigned to either a CBT-based treatment program or existing therapeutic community (TC)-based treatment. The CBT treatment program was developed based on the Matrix Model that considers cultural and social factors in the Philippines. After 6 months of treatment, there will be a three-month follow-up, when the participants’ drug use (tested through urine testing) and other psychological variables, including craving, coping skills, and well-being, will be compared. Potential participants are given a summary of the study and a consent form. The consent form is signed and dated by participants prior to their study participation. Ethical approval was obtained prior to the commencement of the study. Discussion This is the first randomized controlled trial to compare the residential CBT program and the TC model for methamphetamine users in the Philippines. The study aims to fill the current knowledge and capacity gaps by introducing a CBT-based treatment program to improve the psychosocial well-being of drug users in the Philippines. Moreover, if the effectiveness of the treatment program is demonstrated, anti-drug campaigns and severe sanctions against drug users may be reconsidered. Trial registration UMIN Clinical Trials Registry JPRN-UMIN000038597 . Registered on 15 November 2019. Protocol version October 17, 2021 ver.2

Abstract Identifying critical uncertainties about ecological systems can help prioritize research efforts intended to inform management decisions. However, exclusively focusing on the ecological system neglects the objectives of natural resource managers and the associated social values tied to risks and rewards of actions. I demonstrate how to prioritize research efforts for a harvested population by applying expected value of perfect information (EVPI) to harvest decisions made with a density‐independent matrix population model. Research priorities identified by EVPI diverge from priorities identified by matrix elasticity analyses that ignore social utility. Using a density‐dependent harvest model, the value of information about the intrinsic productivity of a population is shown to be sensitive to the socially determined penalty for implementing a harvest rate that deviates from the goal because of imperfection in estimation. Synthesis and applications. The effect of including social values into harvest decision‐making depends on the assumed population model, uncertainty in population vital rates, and the particular form of the utility function used to represent risk/reward of harvest. EVPI analyses that include perceived utility of different outcomes can be used by managers seeking to optimize monitoring and research spending. Collaboration between applied ecologists and social scientists that quantitatively measure peoples' values is needed in many structured decision‐making processes.

Background Among species with size structured demography, population structure is determined by size specific survival and growth rates. This interplay is particularly important among recently settled colonial invertebrates for which survival is low and growth is the only way of escaping the high mortality that small colonies are subject to. Gorgonian corals settling on reefs can grow into colonies of millions of polyps and can be meters tall. However, all colonies start their benthic lives as single polyps, which are subject to high mortality rates. Annual survival among these species increases with size, reflecting the ability of colonies to increasingly survive partial mortality as they grow larger. Methods Data on survival and growth of gorgonian recruits in the genera Eunicea and Pseudoplexaura at two sites on the southern coast of St John, US Virgin Islands were used to generate a stage structured model that characterizes growth of recruits from 0.3 cm until they reach 5 cm height. The model used the frequency distributions of colony growth rates to incorporate variability into the model. Results High probabilities of zero and negative growth increase the time necessary to reach 5 cm and extends the demographic bottleneck caused by high mortality to multiple years. Only 5% of the recruits in the model survived and reached 5 cm height and, on average, recruits required 3 y to reach 5 cm height. Field measurements of recruitment rates often use colony height to differentiate recruits from older colonies, but height cannot unambiguously identify recruits due to the highly variable nature of colony growth. Our model shows how recruitment rates based on height average recruitment and survival across more than a single year, but size-based definitions of recruitment if consistently used can characterize the role of supply and early survival in the population dynamics of species.

Polarimetric synthetic aperture radar (PolSAR) systems are an important remote sensing tool. Such systems can provide high spacial resolution images, but they are contaminated by an interference pattern called multidimensional speckle. This fact requires that PolSAR images receive specialised treatment; particularly, tailored models which are close to PolSAR physical formation are sought. In this paper, we propose two new matrix models which arise from applying the stochastic summation approach to PolSAR, called compound truncated Poisson complex Wishart (CTPCW) and compound geometric complex Wishart (CGCW) distributions. These models offer the unique ability to express multimodal data. Some of their mathematical properties are derived and discussed—characteristic function and Mellin-kind log-cumulants (MLCs). Moreover, maximum likelihood (ML) estimation procedures via expectation maximisation algorithm for CTPCW and CGCW parameters are furnished as well as MLC-based goodness-of-fit graphical tools. Monte Carlo experiment results indicate ML estimates perform at what is asymptotically expected (small bias and mean square error) even for small sample sizes. Finally, our proposals are employed to describe actual PolSAR images, presenting evidence that they can outperform other well-known distributions, such as W m C , G m 0 , and K m . [ABSTRACT FROM AUTHOR]

Two interacting double quantum dots (DQDs) can be suitable candidates for operation in the applications of quantum information processing and computation. In this work, DQDs are modeled by the heterostructure of two-dimensional (2D) MoS2 having 1T-phase embedded in 2H-phase with the aim to investigate the feasibility of controlled-NOT (CNOT) gate operation with the Coulomb interaction. The Hamiltonian of the system is constructed by two models, namely the 2D electronic potential model and the 4 × 4 matrix model whose matrix elements are computed from the approximated two-level systems interaction. The dynamics of states are carried out by the Crank–Nicolson method in the potential model and by the fourth order Runge–Kutta method in the matrix model. Model parameters are analyzed to optimize the CNOT operation feasibility and fidelity, and investigate the behaviors of DQDs in different regimes. Results from both models are in excellent agreement, indicating that the constructed matrix model can be used to simulate dynamical behaviors of two interacting DQDs with lower computational resources. For CNOT operation, the two DQD systems with the Coulomb interaction are feasible, though optimization of engineering parameters is needed to achieve optimal fidelity. [ABSTRACT FROM AUTHOR]

Climate change effects are contributing to widespread declines of amphibians, and pond-breeding species may be particularly sensitive to future drought conditions that restrict wetland hydroperiods and decrease opportunities for successful breeding and recruitment. Pond-breeding amphibian populations can compensate for periodic droughts via episodic booms in recruitment, but studies predict that increased future drought conditions will negatively impact long-term persistence for several species. The southeastern United States is a global hotspot of amphibian biodiversity where future trends in drought conditions are uncertain. This study applied a population viability analysis (PVA) framework for an at-risk amphibian, the gopher frog (Lithobates [Rana] capito), to (i) explore population sensitivity to the frequency of droughts that restrict reproductive events, relative to changes in other demographic rates, and (ii) forecast future population viability over 30 years, given plausible scenarios varying in the frequency and duration of droughts adapted from recent historical patterns in the southeastern United States. Population persistence was highly sensitive to frequency of reproductive success. Persistence was fairly insensitive to all demographic parameters when reproductive success was ≥ 0.7 (i.e., ≤ 3 drought years per decade, on average), but sensitivity to survival of terrestrial stages (juvenile, adults) and initial abundance increased as reproductive success decreased. Persistence probabilities were relatively high (0.63–0.99) across a range of plausible future drought scenarios, with higher persistence probabilities (> 0.89) for all scenarios where drought years did not increase from recent historical conditions. Our results indicate gopher frog populations are likely resilient to periodic droughts that occur in 4 or fewer years per decade, but extirpation of some populations is possible if recent drought patterns repeat or increase during the next 30 years. Estimates of future risk to gopher frog populations can inform forthcoming status assessments and designation decisions of the U.S. Fish and Wildlife Service. More broadly, PVAs incorporating drought dynamics can identify climate thresholds that at-risk, pond-breeding amphibian populations can tolerate, which can inform management actions (e.g., maintaining a range of hydroperiods across proximate wetlands) that provide sufficient frequent breeding opportunities for long-term persistence even under drought conditions.

The role of forests in mitigating climate change by acting as a carbon sink is becoming increasingly important. Forest management practices can either positively or negatively affect the ability of forests to mitigate climate change. The objectives of our study were to: (a) investigate the effects of natural disturbances on long-term carbon sequestration dynamics in forests and (b) identify opportunities to adapt current forest management practices to increase carbon sequestration in forests. The study focused on mixed mountain forests in the Slovenian Alps, dominated by Norway spruce, and used the SLOMATRIX model to simulate forest development. Three forest management scenarios were simulated: (1) no management, (2) business-as-usual and (3) an optimized scenario maximizing carbon sequestration in forests while achieving the required harvest. Our results indicate that both forest management practices and natural disturbances have an impact on carbon sequestration dynamics. Optimizing harvests resulted in changes in the diameter structure and species composition of the harvested trees. Although natural disturbances can hinder the mitigation of climate change impacts, they can also catalyze forest adaptation to climate change and reduce the time required to reach carbon equilibrium.

Management generally targets the most tractable life stage to rescue declining populations; however, that stage may not have the largest influence on recovery. Freshwater turtles are declining globally and early stages are frequently targeted for management, although the effectiveness of these actions on population growth are relatively unknown because of incomplete demographic data. We estimated the hatchling yearly survival rate for a freshwater turtle in the field using in situ enclosures to collect missing demographic information. We used these data to develop demographic models to calculate growth rate for a hypothetical, declining population of wood turtles (Glyptemys insculpta) in Wisconsin, USA, 2014–2019. We modeled growth for populations across a range of scenarios from no management to combinations of nest protection and head‐starting at varying levels of effort. Nest protection alone did not increase population growth rate, while head‐starting alone increased population growth by 0.07, with the largest increase in growth rate, 0.11, resulting from combinations of both approaches. No combination of nest protection and head‐starting, without an increase in adult survival rate from the observed 0.88 to ≥0.95, led to population stabilization or increase. Populations of freshwater turtles, like the wood turtle, will likely only recover with a multi‐faceted approach that targets multiple life stages simultaneously. [ABSTRACT FROM AUTHOR]

Predators may create healthier prey populations by selectively removing diseased individuals. Predators typically prefer some ages of prey over others, which may, or may not, align with those prey ages that are most likely to be diseased.The interaction of age‐specific infection and predation has not been previously explored and likely has sizable effects on disease dynamics. We hypothesize that predator cleansing effects will be greater when the disease and predation occur in the same prey age groups.We examine the predator cleansing effect using a model where both vulnerability to predators and pathogen prevalence vary with age. We tailor this model to chronic wasting disease (CWD) in mule deer and elk populations in the Greater Yellowstone Ecosystem, with empirical data from Yellowstone grey wolves and cougars.Model results suggest that under moderate, yet realistic, predation pressure from cougars and wolves independently, predators may decrease CWD outbreak size substantially and delay the accumulation of symptomatic deer and elk. The magnitude of this effect is driven by the ability of predators to selectively remove late‐stage CWD infections that are likely the most responsible for transmission, but this may not be the age class they typically select. Thus, predators that select for infected young adults over uninfected juveniles have a stronger cleansing effect, and these effects are strengthened when transmission rates increase with increasing prey morbidity. There are also trade‐offs from a management perspective—that is, increasing predator kill rates can result in opposing forces on prey abundance and CWD prevalence.Our modelling exploration shows that predators have the potential to reduce prevalence in prey populations when prey age and disease severity are considered, yet the strength of this effect is influenced by predators' selection for demography or body condition. Current CWD management focuses on increasing cervid hunting as the primary management tool, and our results suggest predators may also be a useful tool under certain conditions, but not necessarily without additional impacts on host abundance and demography. Protected areas with predator populations will play a large role in informing the debate over predator impacts on disease. [ABSTRACT FROM AUTHOR]

Fog computing systems, by design, have a high degree of redundancy in terms of computing and storage resources. To make the most of this redundancy, coding techniques can be used to transform the data being transferred and processed. Two specific coding ideas that have been proposed for use in fog computing are minimum bandwidth codes and minimum latency codes. These codes have the potential to significantly reduce data transfer capacity utilization and computation inactivity. Minimum bandwidth codes focus on reducing the amount of data that needs to be transferred, while minimum latency codes focus on reducing the amount of time it takes for data to be processed. These two coding methods can be combined in a linked coding structure that allows for a trade-off between computation inactivity and communication load, leading to improved system performance. Fog computing has been proposed as a solution to meet the management requirements of the growing Internet of Things (IoT) and smart networks. This research breaks down the capabilities and challenges of fog computing in smart networks, presents the state-of-the-art in the field, defines a fog computing-based smart grid, and provides a use case scenario for the proposed model. [ABSTRACT FROM AUTHOR]

The Hyrcanian forests of Iran are mainly managed with the single-selection silvicultural technique. Despite significant ecological benefits associated with selection cutting, this type of forest management leads towards more challenging situations where it is difficult to maintain and practice successful forestry than in even-aged systems. Therefore, this study provides relevant management tools in the form of models to estimate low growth levels in Hyrcanian forests. In the present study, estimation of the population growth rate and then the allowable cut rate of these forests using a matrix model have been calculated in the Gorazbon district. For this purpose, the data of 256 permanent sample plots measured during the years between 2003 and 2012, as well as the data recorded about the trees harvested according to the forestry plan, have been used. As a first step, the most frequently occurring tree species were divided into four groups (beech, hornbeam, chestnut-leaved oak, and other species). Compartments of the district were divided into two groups of logged and unlogged compartments. The purpose of this division was to estimate the allowable cut and compare its volume with the volumes of observed and predicted allowable cuts obtained from forestry plans. The results showed that the total operated allowable cut (OAC) in logged compartments was more than the estimated allowable cut (EAC). In unlogged compartments, the total predicted allowable cut (PAC) was more than EAC. A comparison of EAC and OAC showed that hornbeam has been harvested more than its potential. However, chestnut-leaved oak and other species group have depicted opposite trends. Our models provide important advancements for estimating allowable cut that can enhance the goal of practicing sustainable forestry. [ABSTRACT FROM AUTHOR]