Generalized convective quasi-equilibrium principle

A generalization of Arakawa and Schubert's convective quasi-equilibrium principle is presented for a closure formulation of mass-flux convection parameterization. The original principle is based on the budget of the cloud work function. This principle is generalized by considering the budget for a vertical integral of an arbitrary convection-related quantity. The closure formulation includes Arakawa and Schubert's quasi-equilibrium, as well as both CAPE and moisture closures as special cases. The formulation also includes new possibilities for considering vertical integrals that are dependent on convective-scale variables, such as the moisture within convection. The generalized convective quasi-equilibrium is defined by a balance between large-scale forcing and convective response for a given vertically-integrated quantity. The latter takes the form of a convolution of a kernel matrix and a mass-flux spectrum, as in the original convective quasi-equilibrium. The kernel reduces to a scalar when either a bulk formulation is adopted, or only large-scale variables are considered within the vertical integral. Various physical implications of the generalized closure are discussed. These include the possibility that precipitation might be considered as a potentially-significant contribution to the large-scale forcing. Two dicta are proposed as guiding physical principles for the specifying a suitable vertically-integrated quantity.

Generalized drivers in the mammalian endangerment process

An important challenge for conservation today is to understand the endangerment process and identify any generalized patterns in how threats occur and aggregate across taxa. Here we use a global database describing main current external threats in mammals to evaluate the prevalence of distinct threatening processes, primarily of anthropogenic origin, and to identify generalized drivers of extinction and their association with vulnerability status and intrinsic species' traits. We detect several primary threat combinations that are generally associated with distinct species. In particular, large and widely distributed mammals are affected by combinations of direct exploitation and threats associated with increasing landscape modification that go from logging to intense human land-use. Meanwhile, small, narrowly distributed species are affected by intensifying levels of landscape modification but are not directly exploited. In general more vulnerable species are affected by a greater number of threats, suggesting increased extinction risk is associated with the accumulation of external threats. Overall, our findings show that endangerment in mammals is strongly associated with increasing habitat loss and degradation caused by human land-use intensification. For large and widely distributed mammals there is the additional risk of being hunted.

Schatten class Toeplitz operators on generalized Fock spaces

In this paper we characterize the Schatten p class membership of Toeplitz operators with positive measure symbols acting on generalized Fock spaces for the full range p>0.

Small states, great power? Gaining influence through intrinsic, derivative, and collective power

In recent years, scholars have devoted increased attention to the agency of small states in International Relations. However, the conventional wisdom remains that while not completely powerful, small states are unlikely to achieve much of significance when faced by great power opposition. This argument, however, implicitly rests on resource-based and compulsory understandings of power. This article explores the implicit connections between the concept of "small state" and diverse concepts of power, asking how we should understand these states' attempts to gain influence and achieve their international political objectives. By connecting the study of small states with additional understandings of power, the article elaborates the broader avenues for influence that are open to many states but are particularly relevant for small states. The article argues that small states' power can be best understood as originating in three categories: “derivative,” collective, and particular-intrinsic. Derivative power, coined by Michael Handel, relies upon the relationship with a great power. Collective power involves building coalitions of supportive states, often through institutions. Particular-intrinsic power relies on the assets of the small state trying to do the influencing. Small states specialize in the bases and means of these types of power, which may have unconventional compulsory, institutional, structural, and productive aspects.