Head in the clouds: a new dwarf frog species of the Physalaemus signifer clade (Leptodactylidae, Leiuperinae) from the top of the Brazilian Atlantic Forest

In an elevational gradient, the mountain top generally presents a reduced species diversity. However, it is there where we often find microendemic and quite often still undescribed species. That prediction is very common in underexplored Neotropical mountains, like those of the Caparaó National Park – a protected area that includes the highest peak of the Atlantic Forest, a megadiverse domain. Up in its top, we found a dwarf frog of the genus Physalaemus (Anura, Leptodactylidae, Leiuperinae), belonging to the P. signifer clade. After an integrative (morphological, bioacoustical, and genetic) analysis, we were able to describe it as a new species and found it to be sister to P. maculiventris. Due to its very restricted distribution at a site with extreme environmental conditions (which includes fires and frosts) and current instability in national environmental policy, we suggest this to be classified as an endangered species. A brief description of its natural history and the description of the species itself will now enable its proper conservation status categorization and the future planning for conservation actions.

System synthesis in elaborating the mechanisms of fuel and energy complex innovation development: Methodological issues

Subject. The article addresses methodological issues to develop the mechanisms facilitating the innovation in the fuel and energy complex. Objectives. I focus on the rationale for the basic provisions of the systems-based approach to the formation of incentive mechanisms to support energy modernization in the light of energy security under conditions of current instability in Russia and in the world. Methods. The study rests on the tenets of systemic economic theory, in particular, the systemic economic paradigm, according to which, the national economy and its sectors are regarded as relatively integral parts of their environment, and are closely related through the exchange of complementary flows of tangible and intangible resources. Results. The paper formulates basic principles of the system synthesis of innovation mechanisms for technical and economic transformation in the said sector. It presents a scheme to design modernization, select ways to promote and support innovation. The modernization and transformation of the energy system are seen as controlled processes. The methods to determine the control actions under system rules are aimed at adapting the control system to changing the objects and their environment during the transformation process. This helps to agree on all changes in sectors within a single system. Conclusions. The offered approach creates a scientific basis for justifying the innovation strategies, forming and studying the organizational and economic mechanisms to encourage innovation in the fuel and energy complex, choosing tools to bolster innovation in different operating environments of energy organization.

Estimating the number of clusters via a corrected clustering instability

We improve instability-based methods for the selection of the number of clusters k in cluster analysis by developing a corrected clustering distance that corrects for the unwanted influence of the distribution of cluster sizes on cluster instability. We show that our corrected instability measure outperforms current instability-based measures across the whole sequence of possible k, overcoming limitations of current insability-based methods for large k. We also compare, for the first time, model-based and model-free approaches to determining cluster-instability and find their performance to be comparable. We make our method available in the R-package .

Влияние электрического поля на энергию активации локальных уровней в полупроводниках со слоистой (GaSe) и кубической структурой (Ga-=SUB=-2-=/SUB=-Se-=SUB=-3-=/SUB=-)

The results of measuring the electrical conductivity of layered crystals (GaSe, GaTe, and their solid solutions) and cubic crystals (Ga_2Se_3) in strong electric fields (up to 5 × 10^5 V/cm) in the temperature range of 77–300 K are presented. These results are compared with predictions of the phenomenological theory of concentration instability in semiconductors. This theory considers the role of the Frenkel effect, which is related to the thermionic ionization of traps causing instability in semiconductors with an S -shaped current–voltage ( I – V ) characteristic. Based on the results of measuring the electrical conductivity of layered and cubic crystals exhibiting the Frenkel effect and described by the theory of current instability in semiconductors, the free-carrier concentration in the aforementioned types of chalcogenide semiconductors is estimated to be n = (3 × 10^13–4 × 10^15) cm^–3.

Venezuela in Crisis: A Backgrounder

This essay provides a rigorous and accessible background to what is likely the most pressing geopolitical issue in twenty-first-century Latin America: the humanitarian crisis in Venezuela under President Nicolás Maduro of the United Socialist Party of Venezuela (PSUV). To this end, it analyzes and connects three distinct political phenomena in Venezuelan history whose interrelated development underpins the country’s current instability: Puntofijismo (1958-1998), Chavismo (1998-2013), and Madurismo (2013-present). It firsts describes the collapse of Puntofijismo, Venezuela’s style of pacted democracy and its oil-dependent petro-state to contextualize the rise of Hugo Chávez’s political project in 1990 known as Bolivarianism. The paper then considers Chávez’s regime and how it continued, yet also departed from, Puntofijismo through clientelism, exclusionary politics, and the creation of an illiberal hybrid regime. Upon this foreground, the paper situates the current student protests, military repression, and humanitarian crisis under President Maduro. Using both English and Spanish-language source material, this paper lays bare the current complex reality that is Venezuela.