The article introduces a novel class of 4R1H mechanisms, where 4R indicates four revolute joints and 1H indicates one helical joint. The paper starts with the type synthesis of these mechanisms, which involves combining two kinematic chains with planar and cylindrical motion types into a single closed-loop kinematic chain. If we fix any link in such a chain, we get a workable mechanism. The synthesis procedure considers two options for the relative arrangement of these two kinematic chains. Adding an H joint to the kinematic chain allows us to design mechanisms whose output link performs spatial motion. Using the proposed synthesis procedure, we develop a family of 4R1H mechanisms. Next, we choose one mechanism as a representative example and consider its mobility, singularity, kinematic, and dynamic analysis. Using screw theory, we confirm the mechanism has one degree of freedom and determine its singular configurations. Kinematic analysis provides closed-form expressions to calculate displacements, velocities, and accelerations of all the mechanism links. Dynamic analysis uses these results to compute the motor torque required for one motion cycle. To verify the suggested analytical algorithms and obtained results, we use computer-aided design tools, which allow us to develop virtual and physical prototypes.

A small trilobite assemblage, including Parabolina (Neoparabolina) frequens, assignable to the Parabolina Fauna, has been recovered from the Furongian (Cambrian Stage 10) Sah Member of the Mila Formation in the Tuyeh–Darvar section, the eastern Alborz Mountains, north Iran. The assemblage includes eight genera and species; two of them, Niobella darvarensis n. sp. and Macropyge (Promacropyge) sahensis n. sp., are new to science. The incursion of a Parabolina fauna into Alborz is confined to a significant drowning event with associated dark-gray shale deposition, which most probably occurred in the lower part of the Cordylodus proavus conodont Zone. While the generic composition of the assemblage is mostly cosmopolitan with the exception of the endemic Alborsella, the occurrence of Indiligens, Macropyge (Promacropyge) sahensis n. sp., Agnostotes sp. aff. A. sulcatus, and Leiagnostus bexelli indicates faunal links with South China and Tarim. Parabolina (Neoparabolina) frequens is widespread mainly in offshore deposits from temperate Gondwana (Armorican terrane assemblage, Argentina) and Baltica of about that age.

UUID: http://zoobank.org/6b3118d0-5907-41b9-af44-cee838c5e630

Predation is a behavior that is commonly unsuccessful, but the cause of failure is often difficult to determine in the fossil record. Here, we report on gastropod drill holes in two Plio- and Miocene bivalve specimens from the Netherlands created from the inner side of the bivalve prey's shell, which we call reverse drill holes. These holes are unequivocally caused by failure of the gastropod drilling predators to make effective use of their chemoreception and mechanoreception sensory adaptations. We hypothesize that the diffuse nature of chemical cues emanating from dense aggregations of living prey could have confused foraging predators and stimulated them to initiate the drilling process on empty valves. Poor decision making due to hunger is an alternative hypothesis. These traces represent the first reported examples of reverse gastropod drill holes from the fossil record, and the first attributed to Naticidae. Compared to other types of failed predation (incomplete drill holes and drill holes in multiply-drilled specimens) in the two assemblages studied, reverse drill holes are rare (< 1% of drill holes). This result implies that the driller's sensory and decision-making processes were generally reliable at distinguishing dead from live prey.

We present our library for universal algebra in the UniMath framework dealing with multi-sorted signatures, their algebras and the basics for equation systems. We show how to implement term algebras over a signature without resorting to general inductive constructions (currently not allowed in UniMath) still retaining the computational nature of the definition. We prove that our single sorted ground term algebras are instances of homotopy W-types. From this perspective, the library enriches UniMath with a computationally well-behaved implementation of a class of W-types. Moreover, we give neat constructions of the univalent categories of algebras and equational algebras by using the formalism of displayed categories and show that the term algebra over a signature is the initial object of the category of algebras. Finally, we showcase the computational relevance of our work by sketching some basic examples from algebra and propositional logic.

This essay discusses how the European Community used its relations with the Third World to leverage increased power in the Cold War. It argues that resuscitating the interwar concept of Eurafrica to emerge as a credible alternative to Cold War superpowers went hand in hand with the systematic effort to distance themselves from the colonial legacy and the American strategy. It claims that it took a dynamic leader – Claude Cheysson – to make the Common Market a pivotal actor of globalism, with regional partnership and support of the new international economic order, until its transformative potential waned with the neoliberal turn of the 1980s.

The datasets on the Italian political class provides two sets of information: (a) census data on a broad spectrum of individual-level variables on elected politicians, offering an updated mapping of the characteristics of more than 20,000 Italian representatives at all governmental levels; (b) survey data on politicians' attitudes towards elections, participation, public opinion, several national and international policy issues, and their views of political representation. Between September 2020 and January 2021, 2134 elected politicians at the local (n = 1917), regional (n = 128), national (n = 75) and European (n = 14) levels were interviewed, making this one of the largest surveys of the Italian political elites ever conducted and a valuable resource for researchers interested in the study of democratic representation.

It is known that hyperbolic linear delay difference equations are shadowable on the half-line. In this article, we prove the converse and hence the equivalence between hyperbolicity and the positive shadowing property for the following two classes of linear delay difference equations: (a) for non-autonomous equations with finite delays and uniformly bounded compact coefficient operators in Banach spaces and (b) for Volterra difference equations with infinite delay in finite dimensional spaces.

This article examines the local context that led to the expulsion of Jews from Eastern Thrace in 1934. Going beyond the conventional state-centric narratives, it unearths the local socio-economic tensions that triggered the locals to target their Jewish neighbors. It highlights three major factors that fueled already-existing nationalist sentiments in the region: some Jewish merchants’ involvement in usury, Turkish–Muslim agricultural producers’ growing indebtedness due to the devastating impact of the Great Depression, and the government’s failure to support producers with appropriate credit policies. Faced with the danger of indebtedness and dispossession, the locals in this context deemed the small Jewish community as “the easy target,” scapegoating it for their ongoing problems amid Turkey’s nationalist political climate in the 1930s.

Hegel’s ‘Natural Law’ essay is widely discussed but its substance and the implications of its argument are misunderstood. Hegel’s essay is most often read via other philosophers. Interpretations of this kind are useful but only illuminate those parts of Hegel’s text that intersect with other philosophers’ concerns. This article takes a different approach by focusing on the entirety of the essay and exploring the implications of its two primary arguments: firstly, that there has been a breach between philosophy and natural law; secondly, that without philosophy natural law is thrown back on its own resources, producing two schools of post-philosophical thought—empiricism and formalism—neither of which is adequate to serve as its foundation. I argue that in response to this inadequacy Hegel sublates empiricism and formalism to develop undistorted intuition as a way of thinking designed to effect the re-philosophization of natural law.

An ultra-wideband current-reused low-noise amplifier (LNA) monolithic microwave integrated circuit design is presented in this letter. Negative feedback networks are employed at both stages of the proposed LNA to expand bandwidth. Furthermore, source adaptive bias networks is designed in the first stage and combined with a current-reused construction to acquire a compact chip size and maintain low power consumption. Then, the validation of design theory is implemented by employing a 0.15-µm gallium arsenide pseudomorphic high-electron-mobility transistor process. The measured results show that the proposed LNA achieves a small signal gain of 15.5–17.8 dB, a noise figure of 3–3.65 dB, and an output 1 dB compression point (OP1 dB) of 14.5–15.5 dBm from the target bandwidth of 2–18 GHz. In addition, the fabricated LNA consumes 220 mW from a 5 V supply and occupies a chip area of 1.2 × 1.5 mm2.