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Aims/hypothesis: The aim of this study was to investigate insulin secretion, insulin sensitivity, disposition index and insulin clearance by glucose tolerance status in individuals with cystic fibrosis (CF) and exocrine pancreatic insufficiency. Methods: In a cross-sectional study, we conducted an extended (ten samples) OGTT in individuals with pancreatic-insufficient CF (PI-CF). Participants were divided into normal glucose tolerance (NGT), early glucose intolerance (EGI), impaired glucose tolerance (IGT) and CF-related diabetes (CFRD) groups. We used three different oral minimal models to assess insulin secretion, insulin sensitivity and insulin clearance during the OGTT. We evaluated insulin secretion using total secretion (Φ total), first-phase secretion (Φ dynamic) and second-phase secretion (Φ static) from the model, and we estimated the disposition index by multiplying Φ total and insulin sensitivity. Results: Among 61 participants (NGT 21%, EGI 33%, IGT 16%, CFRD 30%), insulin secretion indices (Φ total, dynamic and static) were significantly lower in the CFRD group compared with the other groups. Insulin sensitivity declined with worsening in glucose tolerance (p value for trend <0.001) and the disposition index declined between NGT and EGI and between IGT and CFRD. Those with CFRD had elevated insulin clearance compared with NGT (p=0.019) and low insulin secretion (Φ total) was also associated with high insulin clearance (p<0.001). Conclusions/interpretation: In individuals with PI-CF, disposition index declined with incremental impairment in glucose tolerance due to a reduction in both insulin secretion and insulin sensitivity. Moreover in CF, reduced insulin secretion was associated with higher insulin clearance. [ABSTRACT FROM AUTHOR]

We prove the Morrison–Kawamata cone conjecture for projective primitive symplectic varieties with Q -factorial and terminal singularities with b 2 ≥ 5 , from which we derive for instance the finiteness of minimal models of such varieties, up to isomorphisms. To prove the conjecture we establish along the way some results on the monodromy group which may be interesting in their own right, such as the fact that reflections in prime exceptional divisors are integral Hodge monodromy operators which, together with monodromy operators provided by birational transformations, yield a semidirect product decomposition of the monodromy group of Hodge isometries. [ABSTRACT FROM AUTHOR]

Given an NQC log canonical generalized pair (X , B + M) whose underlying variety X is not necessarily Q -factorial, we show that one may run a (K X + B + M) -MMP with scaling of an ample divisor which terminates, provided that (X , B + M) has a minimal model in a weaker sense or that K X + B + M is not pseudo-effective. We also prove the existence of minimal models of pseudo-effective NQC log canonical generalized pairs under various additional assumptions, for instance when the boundary contains an ample divisor. [ABSTRACT FROM AUTHOR]

Some authors claim that minimal models have limited epistemic value (Fumagalli, 2016; Grüne-Yanoff, 2009a). Others defend the epistemic benefits of modelling by invoking the role of robustness analysis for hypothesis confirmation (see, e.g., Levins, 1966; Kuorikoski et al., 2010) but such arguments find much resistance (see, e.g., Odenbaugh & Alexandrova, 2011). In this paper, we offer a Bayesian rationalization and defence of the view that robustness analysis can play a confirmatory role, and thereby shed light on the potential of minimal models for hypothesis confirmation. We illustrate our argument by reference to a case study from macroeconomics. At the same time, we also show that there are cases in which robustness analysis is detrimental to confirmation. We characterize these cases and link them to recent investigations on evidential variety (Landes, 2020b, 2021; Osimani and Landes, forthcoming). We conclude that robustness analysis over minimal models can confirm, but its confirmatory value depends on concrete circumstances. [ABSTRACT FROM AUTHOR]

We discuss the regularization of certain hypergeometric integrals appearing in 2D CFT, a step needed in the construction of the BPZ minimal models via the Coulomb gas formalism. The method is a generalization of Pochhammer’s regularization of the Euler Beta-function. The constructions of the relevant homology classes are inspired by a recent singular-geometric analysis of the Dotsenko–Fateev integrand. [ABSTRACT FROM AUTHOR]

Active materials are self-propelled non-living entities which, in some circumstances, exhibit a number of cognitively interesting behaviors such as gradient-following, avoiding obstacles, signaling and group coordination. This has led to scientific and philosophical discussion of whether this may make them useful as minimal models of cognition (Hanczyc, 2014; McGivern, 2019). Batterman and Rice (2014) have argued that what makes a minimal model explanatory is that the model is ultimately in the same universality class as the target system, which underpins why it exhibits the same macrobehavior. We appeal to recent research in basal cognition (Lyon et al., 2021) to establish appropriate target systems and essential features of cognition as a target of modeling. Looking at self-propelled oil droplets, a type of active material, we do not find that organization alone indicates that these systems exhibit the essential features of cognition. We then examine the specific behaviors of oil droplets but also fail to find that these demonstrate the essential features of cognition. Without a universality class, Batterman & Rice’s account of the explanatory power of minimal models simply does not apply to cognition. However, we also want to stress that it is not intended to; cognition is not the same type of behavioral phenomena as those found in physics. We then look to the minimal cognition methodology of Beer (1996, 2020a, b) to show how active materials can be explanatorily valuable regardless of their cognitive status because they engage in specific behaviors that have traditionally been expected to involve internal representational dynamics, revealing misconceptions about the cognitive underpinnings of certain, specific behaviors in target systems where such behaviors are cognitive. Further, Beer’s models can also be genuinely explanatory by providing dynamical explanations. [ABSTRACT FROM AUTHOR]

Let Z be a nondegenerate hypersurface in a d-dimensional torus (C*)d defined by a Laurent polynomial f with a d-dimensional Newton polytope P. The subset F(P) ⊂ P consisting of all points in P having integral distance at least 1 to all integral supporting hyperplanes of P is called the Fine interior of P. If F(P) ≠ ∅, we construct a unique projective model Z of Z having at worst canonical singularities and obtain minimal models Z of Z by crepant morphisms b Z → Z. We show that the Kodaira dimension κ = κ(Z) equals min{d - 1, dim F(P)} and the general fibers in the Iitaka fibration of the canonical model Z are nondegenerate (d - 1 - ΰ)-dimensional toric hypersurfaces of Kodaira dimension 0. Using F(P), we obtain a simple combinatorial formula for the intersection number (KZ)d-1. [ABSTRACT FROM AUTHOR]

Square-wave bursting is an activity pattern common to a variety of neuronal and endocrine cell models that has been linked to central pattern generation for respiration and other physiological functions. Many of the reduced mathematical models that exhibit square-wave bursting yield transitions to an alternative pseudo-plateau bursting pattern with small parameter changes. This susceptibility to activity change could represent a problematic feature in settings where the release events triggered by spike production are necessary for function. In this work, we analyze how model bursting and other activity patterns vary with changes in a timescale associated with the conductance of a fast inward current. Specifically, using numerical simulations and dynamical systems methods, such as fast-slow decomposition and bifurcation and phase-plane analysis, we demonstrate and explain how the presence of a slow negative feedback associated with a gradual reduction of a fast inward current in these models helps to maintain the presence of spikes within the active phases of bursts. Therefore, although such a negative feedback is not necessary for burst production, we find that its presence generates a robustness that may be important for function. [ABSTRACT FROM AUTHOR]

In this article, we consider Answer Set Programming (ASP). It is a declarative problem solving paradigm that can be used to encode a problem as a logic program whose answer sets correspond to the solutions of the problem. It has beenwidely applied in various domains in AI and beyond. Given that answer sets are supposed to yield solutions to the original problem, the question of "why a set of atoms is an answer set" becomes important for both semantics understanding and program debugging. It has been well investigated for normal logic programs. However, for the class of disjunctive logic programs, which is a substantial extension of that of normal logic programs, this question has not been addressed much. In this article, we propose a notion of reduct for disjunctive logic programs and show how it can provide answers to the aforementioned question. First, we show that for each answer set, its reduct provides a resolution proof for each atom in it. We then further consider minimal sets of rules that will be sufficient to provide resolution proofs for sets of atoms. Such sets of rules will be called witnesses and are the focus of this article. We study complexity issues of computing various witnesses and provide algorithms for computing them. In particular, we show that the problem is tractable for normal and headcycle-free disjunctive logic programs, but intractable for general disjunctive logic programs. We also conducted some experiments and found that for many well-known ASP and SAT benchmarks, computing a minimal witness for an atom of an answer set is often feasible. [ABSTRACT FROM AUTHOR]

We examine a hierarchy of minimal conceptual models for tropical cyclone intensification. These models are framed mostly in terms of axisymmetric balance dynamics. In the first set of models, the heating rate is prescribed in such a way to mimic a deep overturning circulation with convergence in the lower troposphere and divergence in the upper troposphere, characteristic of a region of deep moist convection. In the second set, the heating rate is related explicitly to the latent heat release of ascending air parcels. The release of latent heat markedly reduces the local static stability of ascending air, raising two possibilities in the balance framework. The first possibility is that the effective static stability and the related discriminant in the Eliassen equation for the overturning circulation in saturated air, although small, remains positive so the Eliassen equation is globally elliptic. The second possibility, the more likely one during vortex intensification, is that the effective static stability in saturated air is negative and the Eliassen equation becomes locally hyperbolic. These models help to understand the differences between the early Ooyama models of 1968 and 1969, the Emanuel, 1989 model, and the later Emanuel models of 1995, 1997 and 2012. They provide insight also into the popular explanation of the WISHE feedback mechanism for tropical cyclone intensification. Some implications for recent work are discussed.

We show that minimal models of Q -factorial NQC log canonical generalised pairs exist, assuming the existence of minimal models of smooth varieties. More generally, we prove that on a Q -factorial NQC log canonical generalised pair (X , B + M) we can run an MMP with scaling of an ample divisor which terminates, assuming that it admits an NQC weak Zariski decomposition or that K X + B + M is not pseudoeffective. As a consequence, we establish several existence results for minimal models and Mori fibre spaces. [ABSTRACT FROM AUTHOR]

We examine a hierarchy of minimal conceptual models for tropical cyclone intensification. These models are framed mostly in terms of axisymmetric balance dynamics. In the first set of models, the heating rate is prescribed in such a way to mimic a deep overturning circulation with convergence in the lower troposphere and divergence in the upper troposphere, characteristic of a region of deep moist convection. In the second set, the heating rate is related explicitly to the latent heat release of ascending air parcels. The release of latent heat markedly reduces the local static stability of ascending air, raising two possibilities in the balance framework. The first possibility is that the effective static stability and the related discriminant in the Eliassen equation for the overturning circulation in saturated air, although small, remains positive so the Eliassen equation is globally elliptic. The second possibility, the more likely one during vortex intensification, is that the effective static stability in saturated air is negative and the Eliassen equation becomes locally hyperbolic. These models help to understand the differences between the early Ooyama models of 1968 and 1969, the Emanuel, 1989 model, and the later Emanuel models of 1995, 1997 and 2012. They provide insight also into the popular explanation of the WISHE feedback mechanism for tropical cyclone intensification. Some implications for recent work are discussed. [ABSTRACT FROM AUTHOR]

We introduce a construction that produces from each bialgebra H an operad Ass H controlling associative algebras in the monoidal category of H-modules or, briefly, H-algebras. When the underlying algebra of this bialgebra is Koszul, we give explicit formulas for the minimal model of this operad depending only on the coproduct of H and the Koszul model of H. This operad is seldom quadratic—and hence does not fall within the reach of Koszul duality theory—so our work provides a new rich family of examples where an explicit minimal model of an operad can be obtained. As an application, we observe that if we take H to be the mod-2 Steenrod algebra A , then this notion of an associative H-algebra coincides with the usual notion of an A -algebra considered by homotopy theorists. This makes available to us an operad Ass A along with its minimal model that controls the category of associative A -algebras, and the notion of strong homotopy associative A -algebras. [ABSTRACT FROM AUTHOR]

We show that minimal models of log canonical pairs exist, assuming the existence of minimal models of smooth varieties. [ABSTRACT FROM AUTHOR]

We readily infer that animals make decisions, but what this implies is usually not clearly defined. The notion of 'decision-making' ultimately stems from human introspection, and is thus loaded with anthropomorphic assumptions. Notably, the decision is made internally, is based on information, and precedes the goal directed behaviour. Also, making a decision implies that 'something' did it, thus hints at the presence of a cognitive mind, whose existence is independent of the decision itself. This view may convey some truth, but here I take the opposite stance. Using examples from research in insect navigation, this essay highlights how apparent decisions can emerge without a brain, how actions can precede information or how sophisticated goal directed behaviours can be implemented without neural decisions. This perspective requires us to shake off the idea that behaviour is a consequence of the brain; and embrace the concept that movements arise from – as much as participate in – distributed interactions between various computational centres – including the body – that reverberate in closed-loop with the environment. From this perspective we may start to picture how a cognitive mind can be the consequence, rather than the cause, of such neural and body movements. • Movements can fundamentally transform the task for the brain. • A same brain in different bodies or situations produces different behaviors. • Clear-cut apparent decisions can arise without top-down control. • A cognitive being may result from synchronisation of distributed processes. [ABSTRACT FROM AUTHOR]

We show how to compute the Tamarkin-Tsygan calculus of an associative algebra by providing, for a given cofibrant replacement of it, a 'small' Calc∞-model of its calculus, which we make somewhat explicit at the level of Calc-algebras. To do this, we prove that the operad Calc is inhomogeneous Koszul; to our best knowledge, this result is new. We illustrate our technique by carrying out some computations for two monomial associative algebras using the cofibrant replacement obtained by the author in [39]. [ABSTRACT FROM AUTHOR]

Let Y be a (partial) minimal model of a scheme V with a cluster structure (of type A , X or of a quotient of A or a fibre of X). Under natural assumptions, for every choice of seed we associate a Newton–Okounkov body to every divisor on Y supported on Y ∖ V and show that these Newton–Okounkov bodies are positive sets in the sense of Gross, Hacking, Keel and Kontsevich [31]. This construction essentially reverses the procedure in [31] that generalizes the polytope construction of a toric variety to the framework of cluster varieties. In a closely related setting, we consider cases where Y is a projective variety whose universal torsor UT Y is a partial minimal model of a scheme with a cluster structure of type A. If the theta functions parametrized by the integral points of the associated superpotential cone form a basis of the ring of algebraic functions on UT Y and the action of the torus T Pic (Y) ⁎ on UT Y is compatible with the cluster structure, then for every choice of seed we associate a Newton–Okounkov body to every line bundle on Y. We prove that any such Newton–Okounkov body is a positive set and that Y is a minimal model of a quotient of a cluster A -variety by the action of a torus. Our constructions lead to the notion of the intrinsic Newton–Okounkov body associated to a boundary divisor in a partial minimal model of a scheme with a cluster structure. This notion is intrinsic as it relies only on the geometric input, making no reference to the auxiliary data of a valuation or a choice of seed. The intrinsic Newton–Okounkov body lives in a real tropical space rather than a real vector space. A choice of seed gives an identification of this tropical space with a vector space, and in turn of the intrinsic Newton–Okounkov body with a usual Newton–Okounkov body associated to the choice of seed. In particular, the Newton–Okounkov bodies associated to seeds are related to each other by tropicalized cluster transformations providing a wide class of examples of Newton-Okounkov bodies exhibiting a wall-crossing phenomenon in the sense of Escobar–Harada [18]. This approach includes the partial flag varieties that arise as minimal models of cluster varieties (for example full flag varieties and Grassmannians). For the case of Grassmannians, our approach recovers, up to interesting unimodular equivalences, the Newton–Okounkov bodies constructed by Rietsch–Williams in [56]. [ABSTRACT FROM AUTHOR]

In this note, we provide an algorithm that, starting with a Sullivan algebra gives us its minimal model. More concretely, taking as input a (non-minimal) Sullivan algebra A with an ordered finite set of generators preserving the filtration defined on A, we obtain as output a minimal Sullivan algebra with the same rational cohomology as A. This algorithm is a kind of modified AT-model algorithm used, in the past, to compute a chain contraction providing other kinds of topological information such as (co)homology, cup products on cohomology and persistent homology. [ABSTRACT FROM AUTHOR]

Work on minimal cognition raises a variety of questions concerning the boundaries of cognition. Many discussions of minimal cognition assume that the domain of minimal cognition is a subset of the domain of the living. In this article, I consider whether non-living 'active materials' ought to be included as instances of minimal cognition. I argue that seeing such cases as 'minimal models' of (minimal) cognition requires recognising them as members of a class of systems sharing the same basic features and exhibiting the same general patterns of behaviour. Minimal cognition in this sense is a very inclusive concept: rather than specifying some threshold level of cognition or a type of cognition found only in very simple systems, it is a concept of cognition associated with very minimal criteria that pick out only the most essential requirements for a system to exhibit cognitive behaviour. [ABSTRACT FROM AUTHOR]

This special issue highlights the growing interdisciplinary interest in minimal cognition, bringing together a number of philosophers and scientists interested in investigating where, how, and why cognition arises. In what follows, we introduce the topic of minimal cognition by giving a brief look at debates and discussions about the lower bounds of cognition, minimally cognitive behaviors, and the possibility of life-mind continuity. Afterwards, we offer a short summary of each of the contributions to this issue. In the spirit of the Minimal Cognition conferences at the University of Wollongong at which the contributors participated, we hope this special issue will enrich the current state of minimal cognition research by putting a number of different disciplines and approaches into conversation. [ABSTRACT FROM AUTHOR]

In this note, I apply Norton's (Philos Sci 79(2):207–232, 2012) distinction between idealizations and approximations to argue that the epistemic and inferential advantages often taken to accrue to minimal models (Batterman in Br J Philos Sci 53:21–38, 2002) could apply equally to approximations, including "infinite" ones for which there is no consistent model. This shows that the strategy of capturing essential features through minimality extends beyond models, even though the techniques for justifying this extended strategy remain similar. As an application I consider the justification and advantages of the approximation of a inertial reference frame in Norton's dome scenario (Philos Sci 75(5):786–798, 2008), thereby answering a question raised by Laraudogoitia (Synthese 190(14):2925–2941, 2013). [ABSTRACT FROM AUTHOR]

We study the Johansen-Ledoit-Sornette (JLS) model of financial market crashes (Johansen et al. in Int J Theor Appl Financ 3(2):219-255, 2000). On our view, the JLS model is a curious case from the perspective of the recent philosophy of science literature, as it is naturally construed as a “minimal model” in the sense of Batterman and Rice (Philos Sci 81(3):349-376, 2014) that nonetheless provides a causal explanation of market crashes, in the sense of Woodward’s interventionist account of causation (Woodward in Making things happen: a theory of causal explanation. Oxford University Press, Oxford, 2003). [ABSTRACT FROM AUTHOR]

We give a characterization of closed, simply connected, rationally elliptic 6-manifolds in terms of their rational cohomology rings and a partial classification of their real cohomology rings. We classify rational, real and complex homotopy types of closed, simply connected, rationally elliptic 7-manifolds. We give partial results in dimensions 8 and 9. [ABSTRACT FROM AUTHOR]

In the research into the mechanism of brake squeal, minimal models with two degrees of freedom (DoFs) are widely used. Compared with the finite element method, the minimal model is more concise and efficient, making it easier to analyze the effect of parameters. However, how to accurately determine its kinetic parameters is rarely reported in the literature. In this paper, firstly, the finite element model of a disc brake is established and the complex eigenvalue analysis (CEA) is carried out to obtain unstable modes of the brake. Then, an unstable mode with seven nodal diameters predicted by CEA is taken as an example to establish the 2-DoF model. In order that the natural frequency, Hopf bifurcation point and real parts of eigenvalues of the minimal model coincide with that of the unstable mode with seven nodal diameters, the response surface method (RSM) is applied to determine the kinetic parameters of the minimal model. Finally, the parameter-optimized minimal model is achieved. Furthermore, the negative slope of friction-velocity characteristic is introduced into the model, and transient analysis (TA) is used to study the effect of braking velocity on stability of the brake system. The results show that the brake system becomes unstable when braking velocity is lower than a critical value. The lower the velocity is, the worse the stability appears, and the higher the brake squeal propensity is. [ABSTRACT FROM AUTHOR]

Answer Set Programming (ASP) is a well-known logic-based formalism that has been used to model and solve a variety of AI problems. For several years, ASP implementations primarily focused on the main computational task: the computation of one answer set of a (logic) program. Nonetheless, several AI problems, that can be conveniently modelled in ASP, require to enumerate solutions characterized by an optimality property that can be expressed in terms of subset-minimality with respect to some objective atoms. In this context, solutions are often either (i) answer sets that are subset-minimal w.r.t. the objective atoms or (ii) atoms that are contained in all subset-minimal answer sets, or (iii) sets of atoms that enforce the absence of answer sets on the ASP program at hand — such sets are referred to as minimal unsatisfiable subsets (MUSes). In all the above-mentioned cases, the corresponding computational task is currently not supported by plain state-of-the-art ASP solvers. In this paper, we study formally these tasks and fill the gap in current implementations by proposing several algorithms to enumerate MUSes and subset-minimal answer sets, as well as perform cautious reasoning on subset-minimal answer sets. We implement our algorithms on top of wasp and perform an experimental analysis on several hard benchmarks showing the good performance of our implementation. [ABSTRACT FROM AUTHOR]