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Abstract We review a sequence of papers in which we construct the λ ϕ 4 ⋆ 4 -model and the λ ϕ 2 , 4 , 6 ⋆ 3 -models on noncommutative Moyal space by a common method. Thereby we show that not only the Kontsevich model λ Φ 3 but also the λ Φ 4 4 -model is integrable in a certain scaling limit which corresponds to infinitely large Moyal deformation parameter. Surprisingly, this limit gives rise to Schwinger functions on commutative Euclidean space. Our explicit formulae permit us to discuss reflection positivity of these Schwinger functions. [ABSTRACT FROM AUTHOR]

The matrix model thermoeconomics theory has been widely applied in the energy technology analysis to optimize energy technologies, improve energy utilization efficiency and reduce pollutant emissions. This paper uses the matrix model thermoeconomics theory to analyze the thermodynamics and economics of the energy thermodynamic system, adopts the simulation technology for modelling and then gives an optimized strategy. According to the research results, the matrix model thermoeconomics theory takes into account both thermodynamics and economics when being applied to address energy technology problems, so the analysis is more comprehensive and accurate; the improved local-global decomposition optimization method (LGDO), by combining the advantages of both "global optimization" and "local optimization", has the characteristics of fast convergence and low error, making it more applicable. Through this research, it can be found that the energy technology analysis based on the matrix model thermoeconomics theory is of important theoretical and practical significance in improving the energy utilization and core competitiveness of energy technologies in China. [ABSTRACT FROM AUTHOR]

Tree species of three growth forms (evergreen conifers, deciduous hardwoods, and evergreen hardwoods) codominate at the northern distribution limit of evergreen hardwoods in central Japan. This study examined the stand dynamics and competition during 13 years at a single plot to reveal how three growth forms codominate at the ecotone. Species were characterized as large DBH and low tree density for evergreen conifers, and conversely for evergreen hardwoods. Total basal area increased during the examined period, accompanied with the reduction in tree density (i.e., mortality exceeded the recruitment rate). Mortality increased with time especially for small trees of deciduous hardwoods. The effect of competition among the three growth forms on tree growth was not detected. Species were classified into two axes. Ingrowth and recruitment rates of large evergreen conifers were lower than those of small evergreen hardwoods. The population growth rate was lower in species with greater mortality within each growth form. Deciduous hardwoods showed the highest mortality and lowest population growth rates among the three growth forms. Although the tree‐ring analysis revealed that disturbances occurred to some extent, the current disturbance regime would not trigger the regeneration of deciduous hardwoods. This study suggests that negative relations of maximum DBH with ingrowth and recruitment rates contribute to codominance of evergreen conifers and evergreen hardwoods, and more frequent or larger disturbances than at present are necessary for regeneration of deciduous hardwoods. This study was conducted based on the long‐term 13‐year field observation at the northern distribution limits of evergreen hardwood species. We analyzed stand structure, stand dynamics, tree competition during 13 years, and population growth rates by matrix model. Therefore, this study analyzed thoroughly how dominant tree species of three growth forms (evergreen conifers, deciduous hardwoods, and evergreen hardwoods) maintain their population at a latitudinal ecotone from various analyses. [ABSTRACT FROM AUTHOR]

Bumblebees inhabit spatially heterogeneous landscapes that are likely characterized by population sources and sinks. To date, most studies of bumblebee habitat requirements have examined static relationships between worker abundance and habitat characteristics. However, if habitat types are linked by dispersal, source‐sink dynamics could alter overall population sensitivity to habitat loss, changing conclusions from static approaches.Here, we used empirically derived spatial matrix models to study source‐sink population dynamics of bumblebees in heterogeneous environments. We used these models to assess population sensitivity to habitat loss and to examine the population dynamics that could occur under rapid habitat change.Loss of natural habitat reduced long‐term population growth rates, and more natural habitat was required to sustain bumblebee species with long‐distance dispersal than species with short‐distance dispersal. The long‐term relative density of colonies in each habitat type depended on landscape structure and bumblebee dispersal ability. Under most conditions, high‐quality habitat contained higher densities of colonies than low‐quality habitats. However, low‐quality habitat could contain higher densities than high‐quality habitats if populations were in long‐term decline.Rapid loss or restoration of natural habitat produced transient population dynamics that differed from long‐term dynamics. After large landscape perturbations that affected population structure, transient dynamics persisted for 4–8 years and were longest for species with short dispersal in highly aggregated landscapes. While transient dynamics were short in duration, they caused large effects on long‐term population density.Synthesis and applications. When habitats are linked by dispersal or populations have recently experienced perturbations, patterns of abundance on the landscape may not reflect variation in habitat quality. Spatially structured matrix population models are practical tools than can be used to account for nonequilibrium and source‐sink dynamics. For bumblebees, population sensitivity to habitat loss and the duration of transient dynamics depend on dispersal ability and landscape configuration. Demographic approaches such as ours can help to disentangle population patterns from processes and will therefore be valuable for guiding conservation and management. When habitats are linked by dispersal or populations have recently experienced perturbations, patterns of abundance on the landscape may not reflect variation in habitat quality. Spatially structured matrix population models are practical tools than can be used to account for nonequilibrium and source‐sink dynamics. For bumblebees, population sensitivity to habitat loss and the duration of transient dynamics depend on dispersal ability and landscape configuration. Demographic approaches such as ours can help to disentangle population patterns from processes and will therefore be valuable for guiding conservation and management. [ABSTRACT FROM AUTHOR]

Population dynamics are the result of an interplay between extrinsic and intrinsic environmental drivers. Predicting the effects of environmental change on wildlife populations therefore requires a thorough understanding of the mechanisms through which different environmental drivers interact to generate changes in population size and structure.In this study, we disentangled the roles of temperature, food availability and population density in shaping short‐ and long‐term population dynamics of the African striped mouse, a small rodent inhabiting a semidesert with high intra‐ and interannual variation in environmental conditions.We parameterized a female‐only stage‐structured matrix population model with vital rates depending on temperature, food availability and population density, using monthly mark–recapture data from 1609 mice trapped over 9 years (2005–2014). We then applied perturbation analyses to determine relative strengths and demographic pathways of these drivers in affecting population dynamics. Furthermore, we used stochastic population projections to gain insights into how three different climate change scenarios might affect size, structure and persistence of this population.We identified food availability, acting through reproduction, as the main driver of changes in both short‐ and long‐term population dynamics. This mechanism was mediated by strong density feedbacks, which stabilized the population after high peaks and allowed it to recover from detrimental crashes. Density dependence thus buffered the population against environmental change, and even adverse climate change scenarios were predicted to have little effect on population persistence (extinction risk over 100 years <5%) despite leading to overall lower abundances.Explicitly linking environment–demography relationships to population dynamics allowed us to accurately capture past population dynamics. It further enabled establishing the roles and relative importances of extrinsic and intrinsic environmental drivers, and we conclude that doing this is essential when investigating impacts of climate change on wildlife populations. Small mammal populations are sensitive to their environment and strongly regulated by density. Using state‐of‐the‐art demographic models, the authors show not only that population dynamics of a semidesert rodent are buffered against environmental change by strong density feedbacks, but quantify through which demographic pathways this regulation works. [ABSTRACT FROM AUTHOR]

This study proposes a discrete optimal control model to obtain harvest strategies that maximize the net present value (NPV) of the timber harvested from uneven-aged Pinus nigra stands located in the Spanish Iberian System, between two stable positions. The model was constructed using an objective function that integrates financial data on the harvesting operations with a matrix model describing the population dynamics. The initial and final states are given by the stable diameter distribution of the stand, and the planning horizon is 70 years. The scenario analysis corresponding to the optimal solutions revealed that the stand diameter distribution does not deviate substantially from the equilibrium position over time and that the NPV for the optimal harvesting schedule was always greater than the NPV for the “sustainable/stable” harvesting strategy. The NPV increase for the different scenarios is between 5.36% and 14.43%, showing a greater increase in higher site index scenarios and higher recruitments.

Timber extractions non planned affect negatively in the reduction of forest cover, proper management and planned with minor extractions preserve the natural production allow for longer and sustainable forms a stand to benefit local populations and the same ecosystem. In the basin of Acero Marca has two stands Alnus acuminata that they are extracted continuously. With the purpose of planning the extraction of timber resourses were constructed and evaluated matrix models sustainable harvest of this species on the basis of structures of age. For this, two old structures we worked following a dendrochronological analysis and demographic model of the forestall mass, from making local information by transectos Gentry. According to the demographic model, the potential regression evidences significant differences (p< 0.001) that only it explains 45.5 % of the existent variation, the remainder is explained by the environmental variation, it allowed establishing two elderly structures, the first with seven classes and the second one with two classes. The results demonstrate the first age structure suggest than models 1 to 4 are feasible in time. The sensitivity analysis shows that simulate selective harvests straight trees of 10 to 90% (models 1 to 4) of categories 4, 5, 6 and 7 from the sixth year, the stand would not be adversely affected λ> 1 and could be the most appropriate for a planned extraction becoming sustainable over time. The second structure of age proved extremely sensitive to any change. To use the matrix models is not a simple path of going over. In spite of the results, the matrix models joined to ample experience of the observer would be able to present proposals of sustainable handling of the forestal resources.

Greenhouses had to be designed to sustain permanent maintenance and crop loads as well as the site-specific climatic conditions, with wind being the most damaging. However, both the structure and foundation are regularly empirically calculated, which could lead to structural inadequacies or cost ineffectiveness. Thus, in this paper, the structural assessment of a multi-tunnel greenhouse was carried out. Firstly, wind loads were assessed through computational fluid dynamics (CFD). Then, the buckling failure mode when either the European Standard (EN) or the CFD wind loads were contemplated was assessed by a finite element method (FEM). Conversely to the EN 13031-1, CFD wind loads generated a suction in the 0–55° region of the first tunnel and a 60% reduction of the external pressure coefficients in the third tunnel was not detected. Moreover, the first-order buckling eigenvalues were reduced (32–57%), which resulted in the need for a different calculation method (i.e., elastoplastic analysis), and global buckling modes similar to local buckling shape were detected. Finally, the foundation was studied by the FEM and a matrix method based on the Wrinkler model. The stresses and deformations arising from the proposed matrix method were conservative compared to those obtained by the FEM.

It has been shown recently by Saad, Shenker and Stanford that the genus expansion of a certain matrix integral generates partition functions of Jackiw-Teitelboim (JT) quantum gravity on Riemann surfaces of arbitrary genus with any fixed number of boundaries. We use an extension of this integral for studying gas of baby universes or wormholes in JT gravity. To investigate the gas nonperturbatively we explore the generating functional of baby universes in the matrix model. The simple particular case when the matrix integral includes the exponential potential is discussed in some detail. We argue that there is a phase transition in the gas of baby universes.

The weakness of the population matrix models is that they do not take into account the variation inside the class. In this study, we introduce an approach to add height variation of the trees to the diameter-structured matrix models. In this approach, a new sub-model that describes the height growth of the trees is included in the diameter-structured model. We used this height- and diameter-structured matrix model to maximize the net present value (NPV) for the remaining part of the ongoing rotation for Scots pine (Pinus sylvestris L.) stand and studied how the height variation affects to the results obtained through stand-level optimization. In the optimization, the height variation was taken into account by setting the lower saw-log price for the short trees. The results show that including the height variation into the optimization reduced the financial outcome by 16−18% and considerably changed the structure of optimal management (e.g., timings for thinnings, rotation period and intensity of thinnings). We introduced an approach that can be applied to include not only height variation but also variation of other tree properties (such as branchiness or the amount of heartwood and sapwood) into the matrix models.

The near-IR spectra of thioacetamide were recorded for the investigation of hydrogen bonding between thioacetamide (TA) and N,N-dimethylalkylamides (DMF, OMA, DMP) in chloroform over the range of 5°C to 55°C. The v0 + amide II combination band has been resolved into contributions from monomeric TA, 1:1 hydrogen bonded complex and 1:2 complex by the parameterized matrix modeling method. The association constants

In this paper a new concept for modeling uneven-aged forests (UEAF) is presented. The term UEAF in this article encloses all forests that deviate from the even-aged structure. The matrix model is area-based, in that the forest under study is described by a distribution of areas over fixed state-spaces spanned by stem number and volume per hectare classes. Dynamics is introduced as transitions of areas inside the state-space during the simulation. Harvesting activities and the occurrence of calamities are explicitly handled. The model is designed to be suitable for large-scale analyses. The concept was tested in an application to Austrian National Forest Inventory (NFI) data. Results shown, including a comparison to older inventory data, indicate that it is worth further elaborating on the concept and the model. The work will be continued and in the next step the model concept will be applied in several other countries.

Objective: This study was an attempt to compare the therapeutic effects of matrix treatment on the severity of addiction and mental health between female and male methamphetamine abusers. Method: From among 121 patients admitted in maintenance treatment centers, 91 patients who met the conditions required for participation in this study were selected and randomly assigned to two separate groups based on gender (female=43 and male=48). In the following, 9 males and 4 females were excluded from the study. Mental Health and Addiction Severity Index was administered to both groups before and after the intervention. Results: The results were indicative of no significant difference in any of the subscales of addiction severity between female and male abusers after treatment. However, the difference in mental health scores was statistically significant. Males experienced an increase in depression in comparison with females whereas females underwent higher levels of anxiety than males. Conclusion: Matrix treatment shows significantly different effects on mental health of females and males.

Abstract For oil spill responses, assessment of the potential environmental exposure and impacts of a spill is crucial. Due to a lack of chronic toxicity data, acute data is used together with precautionary assumptions. The effect on the Arctic keystone (copepod) species Calanus hyperboreus and Calanus glacialis populations is compared using two approaches: a precautionary approach where all exposed individuals die above a defined threshold concentration and a refined (full-dose-response) approach. For this purpose a matrix population model parameterised with data from the literature is used. Population effects of continuous exposures with varying durations were modelled on a range of concentrations. Just above the chronic No Observed Effect Concentration (which is field relevant) the estimated population recovery duration of the precautionary approach was more than 300 times that of the refined approach. With increasing exposure concentration and duration, the effect in the refined approach converges to the maximum effect assumed in the precautionary approach. Highlights • Population models are set up for two Arctic Calanus spp. • Toxic effects of oil on model parameters are included based on theoretical approach. • Recovery is compared using a precautionary and full dose-response approach. • Just above the NOEC the ratio between the two approaches can be more than 300. • This indicates the level of conservatism used in oil spill response. [ABSTRACT FROM AUTHOR]

Abstract: Integral projection and matrix population models are commonly used in ecological and conservation studies to assess the health and extinction risk of populations. These models use one (or more) measurable state variable(s), such as size or age, to predict individual performance, which, ideally, is the sole determinant of an individual's expected fate. However, even if ecologists successfully identify and measure the observable state variable(s) that best predicts individual fate, we are rarely, if ever, able to perfectly measure state for many species, especially those with size structure, where total plant biomass or starch stores, for example, may be the best predictors of fate. Here, we used a series of simulations to test how this imperfect quantification of actual state (“measurement error”) leads to inaccurate prediction of state‐dependent fates and influences the predictions of structured population models. We simulated 10 yr of best practice field data collection using known vital rate functions and incorporated measurement error of different magnitudes and types (completely random, temporal, and individual based) for two size‐structured life histories. We found that even for conservative error rates, most types of measurement error increased the median predicted population growth rate by 1–2% growth per year. However, the magnitude of this error differed substantially with life history strategy and error type, with some scenarios resulting in >8% median overestimation of population growth rate. This effect arises largely from the well‐known econometrics problem of “regression dilution” (overestimation of the intercept and underestimation of the slope of a regression when the predictor variable is measured with error), which in our simulations typically results in overly optimistic predictions of small or young individuals’ vital rates. Our results suggest that the problem of measurement error for state variables, present in many demographic studies but virtually unacknowledged in the ecological literature, may lead to substantial misestimation of population behavior, resulting in erroneous inferences about not only growth, but also extinction risk and other aspects of population dynamics. [ABSTRACT FROM AUTHOR]

Based on the motivation of generalizing the correspondence between the Lax equation for the Toda lattice and the deformation theory of the orthogonal polynomials, we derive a q -deformed version of the Toda equations for both q -Laguerre/Hermite ensembles, and check the compatibility with the quadratic relation. [ABSTRACT FROM AUTHOR]

Purpose: Investigation of vibrations transmitted from automotive to the human body, for evaluating comfort parameters, always has been a concern for car manufacturers. Hence, the study of vertical vibration is more important in comparison with other directions.Objective: To fined and study vertical vibrations in a sitting position in two states, some error criteria and the backrest support effect on the apparent mass responses, as well as biomechanical responses consisting of apparent mass, driving point mechanical impedance and seat-to-head transmissibility.Methods: In this paper, two new biomechanical models are presented in order to study vertical vibrations in the seated posture in both with and without backrest support states. The first model is an optimized five-degrees-of-freedom (5-DoF) lumped-parameter model with a unique structure to display vertical vibrations in one direction. The other one is a new type of model called the matrix model, on which the stiffness and damping matrixes are employed instead of the spring and damper scalar parameters to present vertical vibrations in two directions: vertical and horizontal. The optimal parameters for 5-DoF and matrix models have been determined using genetic algorithms.Results: Some criteria such as sum of square error, root mean square error, mean absolute percentage error and coefficient of determination (R2) were used to evaluate models’ accuracy. The backrest support showed different effects on the module apparent mass responses, and the module apparent mass responses values without backrest support were higher than those of values obtained in the presence of backrest support.Conclusion: As the extracted scientific results from this research we could said that matrix model is a new method which has many advantages over previous methods, such as simplicity, fewer degrees of freedom and high accuracy. [ABSTRACT FROM AUTHOR]

Abstract: Classical biological control has been a key technology in the management of invasive arthropod pests globally for over 120 years, yet rigorous quantitative evaluations of programme success or failure are rare. Here, I used life table and matrix model analyses, and life table response experiments to quantitatively assess a classical biological control programme for an invasive insect pest in the western United States. Life tables and matrix models were developed for populations of Bemisia tabaci (sweetpotato whitefly) on cotton in Arizona before (1997–1999) and after (2001–2010) the permanent establishment of two exotic aphelinid parasitoids. Analyses tested multiple hypotheses relative to the expected outcome of a successful programme. Marginal rates of parasitism, rates of irreplaceable mortality from parasitism, total generational mortality and finite population growth (λ) were unchanged for B. tabaci populations before and after exotic parasitoid establishment. Prospective analyses showed that predation during the final nymphal stadium had the greatest influence on population growth rates regardless of parasitoid establishment. Retrospective LTREs showed that predation and unknown mortality contributed most to changes in λ after parasitoid establishment. Marginal parasitism acted weakly in a direct density dependence fashion after parasitoid establishment, and for all 14 years combined. However, this did not translate into an association between pest population density and marginal rates of parasitism for the 10‐year period following establishment. Synthesis and applications. Rarely are classical biological control programme outcomes assessed rigorously. Life tables, matrix models, and life table response experiments showed that the decline in the pest status of Bemisia tabaci (sweetpotato whitefly) was not associated with the establishment of two exotic parasitoid species in the cotton system. Instead, native arthropod predators play a major role in pest dynamics. Further efforts to enhance conservation of the extant natural enemy community, with focus on increasing mortality in final stage nymphs and adults, may be the most efficient means of increasing biological control services. Analyses deployed here should be more widely applied to assessing and improving biological control generally. [ABSTRACT FROM AUTHOR]

Abstract: The Einstein‐Hilbert action in three dimensions and the transformation rules for the dreibein and spin connection can be naturally described in terms of gauge theory. In this spirit, we use covariant coordinates in noncommutative gauge theory in order to describe 3D gravity in the framework of noncommutative geometry. We consider 3D noncommutative spaces based on SU(2) and SU(1,1), as foliations of fuzzy 2‐spheres and fuzzy 2‐hyperboloids respectively. Then we construct a U(2) × U(2) and a GL(2, C) gauge theory on them, identifying the corresponding noncommutative vielbein and spin connection. We determine the transformations of the fields and an action in terms of a matrix model and discuss its relation to 3D gravity. [ABSTRACT FROM AUTHOR]

Abstract: Population models can facilitate assessment of potential impacts of pesticides on populations or species rather than individuals and have been identified as important tools for pesticide risk assessment of nontarget species including those listed under the Endangered Species Act. Few examples of population models developed for this specific purpose are available; however, population models are commonly used in conservation science as a tool to project the viability of populations and the long‐term outcomes of management actions. We present a population model for Mead's milkweed (Asclepias meadii), a species listed as threatened under the Endangered Species Act throughout its range across the Midwestern United States. We adapted a published population model based on demographic field data for application in pesticide risk assessment. Exposure and effects were modeled as reductions of sets of vital rates in the transition matrices, simulating both lethal and sublethal effects of herbicides. Two herbicides, atrazine and mesotrione, were used as case study examples to evaluate a range of assumptions about potential exposure–effects relationships. In addition, we assessed buffers (i.e., setback distances of herbicide spray applications from the simulated habitat) as hypothetical mitigation scenarios and evaluated their influence on population‐level effects in the model. The model results suggest that buffers can be effective at reducing risk from herbicide drift to plant populations. These case studies demonstrate that existing population models can be adopted and integrated with exposure and effects information for use in pesticide risk assessment. Environ Toxicol Chem 2018;37:2235–2245. © 2018 SETAC [ABSTRACT FROM AUTHOR]

In 2010, Kawai, Shimasaki and one of the present authors (A.T.) showed that the large- N reduction holds on group manifolds in the sense that a large- N gauge theory on a group manifold is realized by a matrix model which is obtained by dimensionally reducing the original theory to zero dimension. In this note, generalizing the above statement, we show that a large- N gauge theory on a group manifold is equivalent to a theory which is obtained by reducing the original theory to its coset space. This is analogous to the statement of the large- N reduction on flat spaces that large- N gauge theories are independent of the volume. [ABSTRACT FROM AUTHOR]

Generation time is an intuitively simple concept, but for structured populations there are multiple definitions and no general understanding of how they relate to each other. François Bienvenu and Stéphane Legendre, in their note “A New Approach to the Generation Time in Matrix Population Models,” appearing in the June 2015 issue of The American Naturalist, introduced a new measure of generation time Ta, the average time between birth events in an ancestral lineage, and derived the remarkably simple formula Ta=λ(v⊤w)/(v⊤Fw) for any matrix model, where F is the fecundity matrix, v is reproductive value, and w is stable population structure. Here I generalize their formula and interpretations of Ta to a continuous or continuous-discrete population structure and derive similar formulas for three other established generation time measures: average parent age across all births at one time (A¯) and mean parent age at birth events for a cohort (μ1) or generation (Tc). The new formulas reveal that these differently defined measures are unexpectedly often identical in value and clarify when they differ. [ABSTRACT FROM AUTHOR]

1. Predictions on population responses to perturbations are often derived from traitbased approaches like integral projection models (IPMs), but are rarely tested. IPMs are constructed from functions that describe survival, growth and reproduction in relation to the traits of individuals and their environment. Although these functions comprise biologically non-informative statistical coefficients within standard IPMs, model parameters of the recently developed dynamic energy budget IPM (DEB-IPM) are life-history traits like "length at maturation" and "maximum reproduction rate". Testing predictions from mechanistic IPMs against empirical observations can therefore provide functional insights into the links between individual life history, the environment and population dynamics. 2. Here, we compared the population dynamics of the bulb mite (Rhizoglyphus robini) predicted by a DEB-IPM with those observed in an experiment where populations experienced daily food rations that were either positively correlated over time (red noise), negatively (blue noise) or uncorrelated (white noise). We also selectively harvested large adults in half of these populations. The model failed to generate detailed predictions of population structure as juvenile numbers were overestimated; likely because juvenile--adult interference competition was underestimated. The model performed well at the population level as, for both harvested and unharvested populations, simulations matched the observed, long-term stochastic growth rate λs. 3. We next generalised the model to investigate how stochastic change affects mite λs, which correlated well with the frequency f of experiencing periods of good environment, but, due to the relationship between f and noise colour ρ, did not correlate well with shifts in ρ. The sensitivity of λs to perturbations in life-history parameters depended on the type of stochastic change, as well as population growth. 4. Our findings show that responses to differential mortality depend on individual life-history traits, environmental characteristics and population growth. As longterm climate change causes ever greater environmental fluctuations, trait-based approaches will be increasingly important in predicting population responses to change. We therefore conclude by illustrating what questions can be examined with mechanistic trait-based models like the DEB-IPM, the answers to which will advance our knowledge of the functional links between individual traits, the environment and population dynamics. [ABSTRACT FROM AUTHOR]

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Background: Methamphetamine dependence on a stable methadone dose is a health problem in Iran (i.e. the most populated Persian Gulf country). However, many Iranian patients are not motivated to enter treatment. Objectives: The studyaimed to assess the efficacy of motivational interviewing for entry to matrix treatment formethamphetamine dependence. Methods: A study was conducted on 275 Persian male and female methadone patients who were methamphetamine-dependent, however they reported unwillingness to receive the matrix model. The study was conducted in 20 methadone services in Karaj, Iran during 2014. Addiction severity index was used to collect data on demographics and illicit drug use. Psychological well-being and social functioning were assessed using the Persian versions of the general health questionnaire-28 and the social functioning subscale of the opiate treatment index. Results: The study indicated that 5 sessions of motivational interviewing were significantly efficacious in increasing attendance in the Matrix Model in the treatment group (P < 0.001). Attendance in motivational interviewing was significantly accompanied with increased psychological well-being (P < 0.001) and social functioning (P < 0.001). Conclusions: Motivational interviewing should be provided for those participants who are methamphetamine dependent but are not motivated for change. Conducting randomized controlled trials is suggested. [ABSTRACT FROM AUTHOR]

The Fiordland crested penguin Eudyptes pachyrhynchus is one of the least studied crested penguin species, with indications the species has a declining population, which would be in line with the historic and contemporary trends for most crested penguins. To determine the current population trend of the Fiordland crested penguin, a number of monitoring programmes using both abundance counts and demographic modelling approaches were carried out between 1990 and 2010 in the northern half of the species' range. A 2.6% ± 0.8% annual decline rate of active nests was detected at 14 monitoring plots, and the number of nests along two coastlines declined annually by 1.2% and 2.6%. Population matrix models using site-specific demographic rates for the species at two South Westland sites indicated contrasting population trends, with one site increasing by 1.6% annually and a second site decreasing at 0.3% annually. Due to concerns about the reproductive parameters used in the model, the trajectory indicated by the nest-chick data was deemed more robust and should be used to inform management. Six potential threats to Fiordland crested penguin were reviewed against the detected population trend and specifically adult survival, but it was determined that there is insufficient understanding about the species, particularly its foraging ecology and effects of fishing and terrestrial predation, to confidently identify the key threats. Therefore, the recommended management action is to address these knowledge gaps. [ABSTRACT FROM AUTHOR]

Given a quantum permutation group G⊂SN+, with orbits having the same size K, we construct a universal matrix model π:C(G)→MK(C(X)), having the property that the images of the standard coordinates uij∈C(G) are projections of rank ≤1. Our conjecture is that this model is inner faithful under suitable algebraic assumptions, and is in addition stationary under suitable analytic assumptions. We prove this conjecture for the classical groups, and for several key families of group duals. [ABSTRACT FROM AUTHOR]

Atlantic salmon Salmo salar is an iconic species of high conservation and economic importance. At sea, individuals typically are subject to sea lice infestation, which can have detrimental effects on their host. Over recent decades, the body condition and marine survival in NE Atlantic stocks have generally decreased, reflected in fewer adults returning to rivers, which is partly attributable to sea lice. We developed a deterministic stage-structured population model to assess condition-mediated population dynamics resulting in changing fecundity, age at sexual maturation and marine survival rate. The model is parameterized using data fromthe North Esk system, north-east Scotland. Both constant and density-dependent juvenile survival rates are considered. We show that even small sea lice-mediated changes in mean body condition of MSW can cause substantial population declines, whereas 1SW condition is less influential. Density dependence alleviates the condition-mediated population effect. The resilience of the population to demographic perturbations declines as adult condition is reduced. Indirect demographic changes in salmonid life-history traits (e.g., body condition) are often considered unimportant for population trajectory. The model shows that Atlantic salmon population dynamics can be highly responsive to sea lice-mediated effects on adult body condition, thus highlighting the importance of non-lethal parasitic long-term effects. [ABSTRACT FROM AUTHOR]

We present variational estimates for the low-lying energies of a simple matrix model that approximates SU(3) Yang-Mills theory on a three-sphere of radius R. By fixing the ground state energy, we obtain the (integrated) renormalization group (RG) equation for the Yang-Mills coupling g as a function of R. This RG equation allows to estimate the mass of other glueball states, which we find to be in excellent agreement with lattice simulations. [ABSTRACT FROM AUTHOR]

Abstract: Both seed predators and herbivores can have profound effects on individual plant growth, reproduction and survival, but their population‐level effects are less well understood. While most plants interact with a suite of seed predators and herbivores over their life cycle, few studies incorporate the effects of multiple interacting partners and multiple life stages on plant population growth. We constructed a matrix model using 6 years of data from a rare, seed‐producing population of American chestnut (Castanea dentata). We combined field demographic data with published experimental results on the effects of pre‐dispersal seed predators (weevils) and post‐dispersal seed predators (scatter‐hoarding vertebrates) and incorporated the effect of vertebrate herbivores estimated from the field data. We explored the impact of these three different animal interactions for short‐term (transient) and long‐term (asymptotic) tree population growth. In addition, we used the model to explore the conditions under which scatter hoarding would function as a mutualism. Seed predators had greater effect on both short‐ and long‐term population growth than herbivores. Although weevil infestation can greatly reduce the probability of germination, pre‐dispersal seed predators had smaller effects on both short‐ or long‐term population growth than post‐dispersal predators. The elasticities of weevil‐related parameters were also small. The effect of browsers on both the short‐ and long‐term population growth rate were the smallest of the effects studied. Post‐dispersal seed predation affected population growth the most in the interactions studied. The probability of seed removal was among the largest elasticities, similar in magnitude to survival of large trees. Synthesis. Our results indicate that neither weevils nor the intensity of browse damage observed at our study site are likely to hinder tree regeneration or reintroduction, although both reduced population growth. Although researchers and forest managers often assume that seeds are unimportant for long‐lived tree populations, our test of this assumption shows that scatterhoarders and other post‐dispersal seed consumers can significantly limit natural regeneration. Forest management that alters scatterhoarder behaviour could have significant effects on tree population dynamics that are largely unexplored. [ABSTRACT FROM AUTHOR]

Abstract: Demographic matrix modelling of invasive plant populations can be a powerful tool to identify life stage transitions for targeted disruption, in order to cause population decline. This approach can provide quantitative estimates of reductions in select vital rates needed to reduce population growth rate (λ) below 1 and can inform the prerelease selection of effective biological control agents, as in the case of two invasive Vincetoxicum species in North America. We parameterized a five life stage matrix model using vital rate data from six populations (field and forest) of Vincetoxicum nigrum and Vincetoxicum rossicum. Elasticity analyses were used to identify life stage transitions and associated vital rates for perturbation through the incorporation of per capita impact data of candidate agents. Several survival, growth and fecundity‐related transitions were identified that were mostly similar across species, habitats and locations, although two populations showed unique population dynamics. Reductions in associated vital rates needed to prevent population growth varied greatly among populations. Defoliation damage and predispersal seed predation can be effective against slower growing forest and field populations of Vincetoxicum species. A fly and bivoltine moth are recommended as priority agents. However, biological control with these same agents will be ineffective against other field populations as well as some forest populations if the intensity of damage is not severe. Synthesis and applications. Control of long‐lived perennial plants, such as species of Vincetoxicum, is projected to occur through disruption of some individual vital rates of survival, growth or fecundity if population increase is low to moderate (λ < 1.6). However, without significant and simultaneous reductions in multiple lower level vital rates, faster growing populations will not be contained with biological control or other management tools. [ABSTRACT FROM AUTHOR]