Negami found an elegant splitting formula for the Tutte polynomial. We present an analogue of this for Bollobás and Riordan’s ribbon graph polynomial, and for the transition polynomial. From this we deduce a splitting formula for the Jones polynomial.

We consider the question of when a Jacobian of a curve of genus $2g$ admits a $(2,2)$-isogeny to a product of two polarized dimension g abelian varieties. We find that one of them must be a Jacobian itself and, if the associated curve is hyperelliptic, so is the other.

For $g=2,$ this allows us to describe $(2,2)$-decomposable genus $4$ Jacobians in terms of Prym varieties. We describe the locus of such genus $4$ curves in terms of the geometry of the Igusa quartic threefold. We also explain how our characterization relates to Prym varieties of unramified double covers of plane quartic curves, and we describe this Prym map in terms of $6$ and $7$ points in $\mathbb {P}^3$.

We also investigate which genus $4$ Jacobians admit a $2$-isogeny to the square of a genus $2$ Jacobian and give a full description of the hyperelliptic ones. While most of the families we find are of the expected dimension $1$, we also find a family of unexpectedly high dimension $2$.

This article traces the visual culture of human genetic engineering over the past decade, focusing on the CRISPR genome editing technology. We argue that the representations surrounding CRISPR exemplify, and to an extent define, this visual culture. We examine the history of CRISPR, particularly its human applications from 2012 to 2022, through a periodization that includes the CRISPR craze, gene therapy initiatives, the He Jiankui controversy and clinical trials. Employing an expanded interpretation of intermediality within science communication, this work addresses the role of figuration across the relationships between specialist science reporting and the mainstream press and between traditional and social media. Using a mixed-methods approach combining visual and social-media analysis, the article presents an empirical analysis of three key figures – the double helix, the scientist and the human subject – and their roles across the discussed phases. The study concludes by articulating the stabilizing, amplifying and affective functions of intermedial figuration within science communication.

The evolution of a rotationally symmetric surface by a linear combination of its radii of curvature is considered. It is known that if the coefficients form certain integer ratios the flow is smooth and can be integrated explicitly. In this paper the non-integer case is considered for certain values of the coefficients and with mild analytic restrictions on the initial surface.

We prove that if the focal points at the north and south poles on the initial surface coincide, the flow converges to a round sphere. Otherwise the flow converges to a non-round Hopf sphere. Conditions on the fall-off of the astigmatism at the poles of the initial surface are also given that ensure the convergence of the flow.

The proof uses the spectral theory of singular Sturm-Liouville operators to construct an eigenbasis for an appropriate space in which the evolution is shown to converge.

Falerii Novi, in the heart of the ager Faliscus, offers an unrivalled opportunity to investigate the peri-urban landscape of a Roman town. The paper presents some of the results of a research project that has been looking at the entire peri-urban landscape of Falerii Novi through a multidisciplinary approach, including extensive geophysical surveys, pedestrian surveys, and targeted excavation. The paper focuses on the area to the south of the city, where a series of geomorphological and archaeological features have been newly detected. The results have revealed that despite the artificial and natural boundaries of the city (i.e., the city wall and the steep ravine of the Rio Purgatorio), the community's efforts in managing, exploiting, and occupying the peri-urban area were substantial. The paper presents the newly recorded evidence of the significant effort put into water management as one of the key factors in shaping the landscape, demonstrating how the geological composition of the territory conditioned the engineering solutions adopted. Finally, the discussion focuses on the discovery of an agricultural area, likely a mixed cultivation system relating to the production of a surplus by the inhabitants of a large suburban villa.

With the increasing demand for sustainable products, greenwashing has become more prevalent and sophisticated over the past decade. To better understand the incentives for firms to greenwash, we develop an evolutionary game-theoretic model in which firms may choose to mimic green behavior without having to bear the cost linked to green investment and production. We provide the conditions for the different evolutionarily stable equilibria. In a second step, we extend the model using agent-based simulations to incorporate path-dependent investment/production costs, history-dependent mimicry effectiveness, peer effects, and localized firm interactions. We show that the simpler model with random matching offers good approximations of the equilibrium conditions in more complex setups, but market segmentation supports green investment and production in contrast to higher penalties. While curtailing opportunities to pretend green behavior boosts green production, we also find that increasing cost efficiencies encourage firms to engage in green production, even in the face of increasingly sophisticated deceptive strategies. Based on our results, we suggest trio-targeted policies that reduce the (initial) costs of green investment/production, curtail opportunities to mimic green behavior, and support segmentation.

This article was submitted to the ‘The Legacy of Giovanni Sartori’ symposium on IPSR/RISP – Italian Political Science Review. The goal of this note is to suggest an alternative approach to the of party family. The literature agrees that individual party families should be ideologically distinct and cohesive but maintains a broad understanding of ‘ideology’. This comes with conceptual and operational complications, including rarely explicit definitions of party family and frequently inconclusive empirical evidence. Instead, I suggest that the historically rooted ideological distinctiveness and uniqueness of party families should be conceived at the issue level. Accordingly, an alternative conceptualisation of party family is proposed: groups of parties whose patterns of issue salience ideologically reflect their historical origins. Importantly, this approach revolves around the identification of party families’ core issues, based on their cleavage/historical origins. Parties belonging to a party family will be the most consistent emphasizers of their core issues within their party system. This note provides a first discussion of how this alternative approach may provide party family scholars with greater clarity, both conceptually and in proposed empirical applications.

This article analyses the agony column ‘Voi e il cinema’, launched in November 1938 in Cine illustrato, one of the most popular film magazines of the time. ‘Voi e il cinema’ invited readers to share their acting aspirations, but also to send in photographs of themselves that might contain the defining feature of a diva: photogenicity. The magazine was flooded with images of ‘ordinary young Italian women’ that created an intermediate visual grammar. Focusing on both the photographs and the editors’ responses, the article reveals how shared consumption practices redefined the relationship between public and private space. It also highlights the distance of the readers’ self-representations from Fascist models and sheds light on the role of American star culture in creating the ‘modern’ subject. Although they were not politically opposed to Fascist models, the photographs reveal a strong desire for social change and the perception of such change, particularly in relation to traditional female roles.

This editorial introduces the first of two special issues of BJPsych Advances devoted to liaison psychiatry, reflecting collaborative healthcare for patients presenting with both physical and mental health conditions, whether in acute general hospitals, out-patient clinics, in-patient wards or accident and emergency departments.

Idiopathic orbital myositis is a rare inflammatory condition that predominantly affects multiple extraocular muscles. Isolated involvement of a single muscle is very uncommon. Isolated levator palpebrae myositis is a diagnostic challenge that should be considered in patients with periocular pain and complete eyelid ptosis without ophthalmoparesis or pupillary dysfunction. We propose a comprehensive set of diagnostic tests to identify the underlying etiology and a recommended treatment regimen. Additionally, we present a case from our clinical practice that illustrates this rare presentation, of which few cases have been described in the literature.

We introduce a new conjecture of global asymptotic stability for nonautonomous systems, which is fashioned along the nonuniform exponential dichotomy spectrum and whose restriction to the autonomous case is related to the classical Markus–Yamabe Conjecture: we prove that the conjecture is fulfilled for a family of triangular systems of nonautonomous differential equations satisfying boundedness assumptions. An essential tool to carry out the proof is a necessary and sufficient condition ensuring the property of nonuniform exponential dichotomy for upper block triangular linear differential systems. We also obtain some byproducts having interest on itself, such as the diagonal significance property in terms of the above-mentioned spectrum.

This article analyses the activities conducted by the Banca Nazionale del Lavoro (BNL) in Spain between 1936 to 1943 to understand Italian policy towards the Francoist regime during that period. In doing so, this piece argues that it is important to adopt a political economy approach that looks at production, trade and industrial investments, always in relation to politics, diplomacy, law, culture and government. In fact, this article establishes that, for the main actors in Rome at the time, all these considerations were inseparable when it came to the Italian policy towards Franco’s Spain. Furthermore, I argue that the BNL initiatives are better understood when situated within the larger history of the Fascist regime in Italy and its imperialistic policies in the Mediterranean area.

This study is the first report on the monotypic Codonaria cistellula (Fol, 1883) Kofoid & Campbell, 1939 from the North-Eastern Arabian Sea (NEAS), Indian Ocean. The species was recorded at a water temperature of 25–26 °C and a salinity of 36‰, from a depth of 75–100 m in the NEAS. Two morphotypes were encountered from the region, yet the lorica opening diameter (LOD) remained within a narrow range of 46–50 µm. Moreover, as the original description lacks information on LOD, the circumscription of the species is difficult due to the lorica polymorphism, warranting further genetic analyses.

Building on previous scholarship on “genetic capital” and the politicization of animal economies, this paper examines how animal breeds and their transnational movement became geopolitical issues in late seventeenth- and eighteenth-century Europe. In particular, it examines how the French government’s efforts to emulate English and Spanish wool production, and to overcome the economic advantage stemming from its rivals’ superior sheep breeds, intensified in the wake of the Seven Years’ War (1756–1763). Despite bans on the exportation of live sheep from Britain and Spain, the French strove to improve their flocks through illicit imports and diplomatic agreements. These efforts culminated in the 1760s, as the Bureau of Commerce began to collaborate with agriculturalists, naturalists, diplomats, and smugglers to bring superior breeds of sheep across the Anglo-French maritime border and the Pyrenean frontier with Spain. These projects developed in tandem with new conceptions of the permanence of race and breed, according to which animals would retain their characteristics in new climates and environments. Combining perspectives from economic, agricultural, political, and cultural history, this article uses the concept of animal mercantilism to open up the geopolitical stakes inherent in understandings of animals, race, and climate.

Two months after its premiere in Leipzig, Ernst Krenek’s Leben des Orest (1930) came to the Berlin Kroll Opera, a notorious centre for experimental, modernist productions. Inevitably, critics compared the two productions, much to the Berlin production’s detriment. In particular, critics faulted the Berlin stage designs by Greek-Italian painter Giorgio de Chirico. I argue that this reception reflected a fundamental divergence in Krenek and de Chirico’s neoclassicism, which was only exacerbated by how neither Krenek nor de Chirico’s neoclassicism aligned with pre-existing expectations about the Kroll Opera’s production aesthetic, as exemplified in Igor Stravinsky’s Oedipus Rex (staged at the Kroll in 1928). Attending to these differences not only explains the troubled reception of Leben des Orest at the Kroll, but also provides fertile ground to examine the complicated and sometimes contradictory meanings ascribed to neoclassicism in the interwar period, especially as it moved between media and across national borders.