Genes involved in melanin production directly impact insect pigmentation and can affect diverse physiology and behaviours. The role these genes have on sex behaviour, however, is unclear. In the present study, the crucial melanin pigment gene black was functionally characterised in an urban pest, the German cockroach, Blattella germanica. RNAi knockdown of B. germanica black (Bgblack) had no effect on survival, but did result in black pigmentation of the thoraxes, abdomens, heads, wings, legs, antennae, and cerci due to cuticular accumulation of melanin. Sex-specific variation in the pigmentation pattern was apparent, with females exhibiting darker coloration on the abdomen and thorax than males. Bgblack knockdown also resulted in wing deformation and negatively impacted the contact sex pheromone-based courtship behaviour of males. This study provides evidence for black function in multiple aspects of B. germanica biology and opens new avenues of exploration for novel pest control strategies.

For an odd prime $p$, we consider free actions of $(\mathbb {Z}_{/{p}})^2$ on $S^{2n-1}\times S^{2n-1}$ given by linear actions of $(\mathbb {Z}_{/{p}})^2$ on $\mathbb {R}^{4n}$. Simple examples include a lens space cross a lens space, but $k$-invariant calculations show that other quotients exist. Using the tools of Postnikov towers and surgery theory, the quotients are classified up to homotopy by the $k$-invariants and up to homeomorphism by the Pontrjagin classes. We will present these results and demonstrate how to calculate the $k$-invariants and the Pontrjagin classes from the rotation numbers.

In July 2022, on the sidelines of the 41st Ordinary Session of the Executive Council of the African Union and the 4th Mid-Year Coordination Summit in Lusaka, Zambia, Heads of state and government, and leaders of delegations of African Union Member States called on member states, African Union through Africa CDC, and partners to recognize, prioritize, and accelerate the establishment and strengthening of public health emergency operation centers (PHEOCs) in the context of health security and in line with Africa’s new public health order. Implementing the declaration requires a multi-dimensional approach that spans across governance, operational capabilities, partnerships, workforce development, and sustainable financing.

It is widely agreed that the increased polarization many countries experience is bad for democracy. However, existing assessments of how polarization affects democracy operate with simplified understandings of both polarization and democracy. Bringing empirical studies and democratic theory into dialogue, I argue that polarization cannot be understood as a single phenomenon that can be evaluated in one way. Moreover, its different kinds affect different parts of the democratic system in distinct ways. First, we must distinguish between the degree of polarization in a given context and the different kinds of polarization at play. Second, we must consider whether people have good reasons for their polarizing behavior or whether it is entirely irrational. If people have good reasons for their polarizing behavior, the problem lies elsewhere than in polarization itself. Third, we must distinguish between the content of polarized opinions and the process of opinion formation. Both can be assessed with democratic criteria, but they raise different questions. Finally, for democratic evaluation it matters where polarization occurs and thus, we must differentiate between different sites of polarization: civil society, election campaigns, and legislatures. I recommend a systemic approach to assessing the democratic implication of polarization, which analyzes both the effects of polarization at different sites and on democracy as a composite whole.

Foreign workers were a common feature in the economy of postwar Czechoslovakia in various periods of the second half of the twentieth century. This article focuses on foreign labor practices during the first economic plans, namely the two-year plan and the first five-year plan between 1947 and 1950. The number of foreign workers at this time didn't exceed twenty thousand persons and their stays in the country were, with only individual exceptions, short. Workers, who found employment in Czechoslovak agriculture and industry in this period, came from different countries including neighboring Poland, Bulgaria, and Romania, but also from Italy. Recruitment of other groups such as workers from Hungary, the Netherlands, or even China is also considered by the article. These foreign laborers worked in Czechoslovakia under various conditions depending on their methods of recruitment and contracting, the duration of their employment, and other important factors. The basic question this article aims to answer is what the role of Gastarbeit was in Czechoslovakia's communist economic policy. It also examines the motivations of countries that sent workers as well as those of the workers themselves. Finally, the article also attempts to analyze the opportunities and limits of these workers’ strategies in the Czechoslovak labor market.

The local structure of rotationally symmetric Finsler surfaces with vanishing flag curvature is completely determined in this paper. A geometric method for constructing such surfaces is introduced. The construction begins with a planar vector field X that depends on two functions of one variable. It is shown that the flow of X could be used to generate a generalized Finsler surface with zero flag curvature. Moreover, this generalized structure reduces to a regular Finsler metric if and only if X has an isochronous center. By relating X to a Liénard system, we obtain the isochronicity condition and discover numerous new examples of complete flat Finsler surfaces, depending on an odd function and an even function.

This article argues that Queen Victoria's Proclamation of 1858, marking the transfer of power from the East India Company to the crown, ushered in a new era of colonial secularity. “Colonial secularity” refers to the myriad ways that normative distinctions between religion and not-religion emerged and proliferated in colonial contexts. The proclamation committed not to interfere in religion, but “religion” is circumscribed, reconceptualized largely as a matter of private conscience set against the purview of the state. As this article explores, it is according to this logic that the abolition of Islamic criminal law after the proclamation could register as noninterference in native religion. At the same time, Christian missionaries contested the proclamation's notions of neutrality to carve out a space in which they might operate.

This article examines the fiscal transformation of Spain's trade with Spanish America during the 17th century. It analyses the taxation of trade combined with the evolution of the Hispanic Monarchy's long-term domestic debt. To this end, the author looks at the almojarifazgo de Indias (main customs duty), its juro (annuity) obligations and the evolution of the transatlantic trade. He argues that the fall in customs revenue and the increasing non-payment of the juros issued against the almojarifazgo were neither a consequence of the alleged crisis of the Carrera de Indias nor of the higher incidence of fraud. The Crown was not interested in exerting greater fiscal pressure on the trade or fighting fraud at the customs houses of Seville and Cadiz as the increased tax revenue would have gone entirely to service the unpaid juros. Instead, the fiscal burden shifted towards extraordinary contributions that were free of juro obligations.

Hearts of cotorsion pairs on extriangulated categories are abelian categories. On the other hand, hearts of twin cotorsion pairs are not always abelian. They were shown to be semi-abelian by Liu and Nakaoka. Moreover, Hassoun and Shah proved that they are quasi-abelian under certain conditions. In this article, we first show that the heart of any twin cotorsion pair has a largest exact category structure and is always quasi-abelian. We also provide a sufficient and necessary condition for the heart of a twin cotorsion pair being abelian. Then by using the results we have got, we investigate the almost split sequences in the hearts of twin cotorsion pairs. Finally, as an application, we show that a Krull–Schmidt, Hom-finite triangulated category has a Serre functor whenever it has a cluster tilting object.

“Aajkal Agra ka mausam kaisa hai?” Queen Victoria asks herself, alone in her sumptuous quarters at Osborne House.1 How is the weather in Agra these days? Polite small talk, the loose change of a British monarch's verbal currency, recasts itself in unfamiliar phonemes as the empress of India practices her Hindustani. Soon, Agra will retreat from the imperial consciousness; it will be time to go to the durbar room, or work on her Urdu writing under the munshi's tutelage, perhaps before lunching on chicken curry.2