The snake robot can be used to monitor and maintain underwater structures and environments. The motion of a snake robot is achieved by lateral undulation which is called the gait pattern of the snake robot. The parameters of a gait pattern need to be adjusted for compensating environmental uncertainties. In this work, 3D motion dynamics of a snake robot for the underwater environment is proposed with vertical motion using the buoyancy variation technique and horizontal motion using lateral undulation. “The neutral buoyant snake robot motion in hypothetical plane and added mass effect is negligible”, these previous assumptions are removed in this work. Two different control algorithms are designed for horizontal and vertical motions. The existing super twisting sliding mode control (STSMC) is used for the horizontal serpentine motion of the snake robot. The control law is designed on a reduced-ordered dynamic system based on virtual holonomic constraints. The vertical motion is achieved by controlling the mass variation using a pump. The water pumps are controlled using the event-based controller or Proportional Derivative (PD) controller. The results of the proposed control technique are verified with various external environmental disturbances and uncertainties to check the robustness of the control approach for various path following cases. Moreover, the results of STSMC scheme are compared with SMC scheme to check the effectiveness of STSMC. The practical implementation of the work is also performed using Simscape Multibody environment where the designed control algorithm is deployed on the virtual snake robot.

Presidential elections are arguably the most consequential recurring political event in the United States. Understanding the factors that determine their outcomes, therefore, is of substantial importance. One proposed factor pertains to presidential candidates' incumbency status, yet its nature is complex and difficult to study with observational data. In particular, the individual-level mechanisms underlying incumbency effects remain unclear. This study proposes many citizens generally believe that, ceteris paribus, presidents should be afforded two terms. Crucially, such a norm implies that incumbency status possesses an inherent effect, operating independent of other mechanisms that may stem from incumbency. A large, pre-registered survey experiment was therefore employed to isolate the effect of incumbency status on presidential vote choice. The experiment finds strong evidence that one-term incumbent candidates have an inherent advantage against their non-incumbent opponents. The results also clarify that the two-term disadvantage present in observational data is not inherent, and is perhaps better understood simply as the absence of the one-term advantage. The study thus points toward a micro-foundational mechanism underlying incumbent-party performance in presidential elections. Finally, analyses of panel data explore which voters may be systematically inclined to vote based upon the incumbency status of presidential candidates.

The current study aims to characterise the complementary feeding practice and identify locally available climate-resilient crops that can be used for complementary feeding among agro-pastoralists in Ethiopia. A phenomenological study in Benna-Tsemay district, comprising focused group discussions, key informant interviews, and household observations, was conducted. A pretested guide was used to capture information regarding types of complementary food, lists of food items, and ingredients included in their complementary formulation. A thematic analysis for emerging points of discussion was carried out. Three major themes, including infant and young child feeding practices, food items included in complementary food, and their consumption frequencies, as well as the incorporation of climate-resilient crops into complementary foods as coping mechanisms, emerged. Breastfeeding was common and regarded as essential. Gruel and porridge from grains, roots, and tubers were regular parts of complementary foods in the study area. Moringa and sorghum were dominantly identified as climate-resilient crops regularly grown and used in complementary foods. Growing these crops was regarded as a coping strategy for drought and seasonal constraints. The district is one of the most drought-prone areas in Ethiopia, compromising the quality of complementary food. Unlike the World Health Organization recommendation, the grains, roots, and tubers-based diet formed the basis of complementary food lacking flesh foods, eggs, pulses, and other fruits and vegetables. Thus, it is recommended to improve complementary food quality through value-addition using locally accessible crops.

This paper investigates the relationship between growth and quality of pension funds. It measures growth in terms of changes in the number of participants and cash flow transfers and appreciates the quality of the funds through the set of information on past results and costs published in the official prospectuses. The results show that growth rewards the best performing funds in the long term, while annual performance and costs have no relevance. Nevertheless, other factors, such as market power and commercial pressure, appear to be more powerful. The existence of conditions of market power capable of attracting investors beyond the actual quality of pension products is undesirable as it harms future pensioners. These results have implications for the Authority, as mandatory information should be suitable to induce investors to identify the best products and direct individual choices toward the public objective of a more efficient market.

This study presents an analysis of the optical variability of the blazar 1E 1458.8+2249 on diverse timescales using multi-band observations, including observations in the optical BVRI bands carried out with the T60 and T100 telescopes from 2020 to 2023 and ZTF gri data from 2018 to 2023. On seven nights, we searched for intraday variability using the power-enhanced F-test and the nested ANOVA test, but no significant variability was found. The long-term light curve shows a variability behaviour in the optical BVRI bands with amplitudes of $\sim$100% and in the gri bands with amplitudes of $\sim$120%, including short-term variability of up to $\sim$1.1 mag. Correlation analysis revealed a strong correlation between the optical multi-band emissions without any time lag. From 62 nightly spectral energy distributions, we obtained spectral indices between 0.826 and 1.360, with an average of $1.128\pm0.063$. The relationships of both spectral indices and colour with respect to brightness indicate a mild BWB trend throughout the observation period, both intraday and long-term. We also performed a periodicity search using the weighted wavelet Z-transform and Lomb–Scargle methods. A recurrent optical emission pattern with a quasi-periodicity of $\sim$340 days is detected in the combined V- and R-band light curves. The observational results indicate that the blazar 1E 1458.8+2249 has a complex variability, while emphasising the need for future observations to unravel its underlying mechanisms.

This paper is the first part in a series of three papers devoted to the study of enumerative invariants of abelian surfaces through the tropical approach. In this paper, we consider the enumeration of genus g curves of fixed degree passing through g points. We compute the tropical multiplicity provided by a correspondence theorem due to T. Nishinou and show that it is possible to refine this multiplicity in the style of the Block–Göttsche refined multiplicity to get tropical refined invariants.

This article presents the results of AMS radiocarbon dating, stable isotope analysis, and FRUITS dietary modelling to investigate dietary variability among sixty individuals buried at Varna in the mid-fifth millennium bc. The principal pattern was the isotopic clustering of some forty-three per cent of the population, which suggests a ‘Varna core diet’, with the remainder showing a wider variety of isotopic profiles. While there is a slight trend for heightened meat and fish consumption among male individuals compared to female and undetermined individuals, the authors found no clear correlation between dietary variation and the well-attested differentiation in material culture in the graves. Three children had isotopic profile and estimated diets unmatched by any of the adults in the sample. Two scenarios, dubbed ‘regional’ and ‘local’, are presented to explain such dietary variability at Varna.

High-elevation environments present harsh challenges for the pursuit of agropastoral subsistence strategies and relatively little is known about the mechanisms early communities employed to adapt to such locations successfully. This article presents the sequential carbon and oxygen analysis of archaeological caprine teeth from Bangga (c. 3000–2200 BP), which is approximately 3750masl on the Tibetan Plateau. Made visible through this method, intra-tooth variation in isotopic composition allows insights into herding strategies that possibly included the provisioning of livestock with groundwater and agricultural fodder and summer grazing in saline or marsh environments. Such intensive provisioning differs markedly from lower-elevation agropastoralism.

This systematic review maps the trends of computer-assisted pronunciation training (CAPT) research based on the pedagogy of second language (L2) pronunciation instruction and assessment. The review was limited to empirical studies investigating the effects of CAPT on healthy L2 learners’ pronunciation. Thirty peer-reviewed journal articles published between 1999 and 2022 were selected based on specific inclusion and exclusion criteria. Data were collected about the studies’ contexts, participants, experimental designs, CAPT systems, pronunciation training scopes and approaches, pronunciation assessment practices, and learning measures. Using a pedagogically informed codebook, the pronunciation training and assessment practices were classified and evaluated based on established L2 pronunciation teaching guidelines. The findings indicated that most of the studies focused on the pronunciation training of adult English learners with an emphasis on the production of segmental features (i.e. vowels and consonants) rather than suprasegmental features (i.e. stress, intonation, and rhythm). Despite the innovation promised by CAPT technology, pronunciation practice in the studies reviewed was characterized by the predominant use of drilling through listen-and-repeat and read-aloud activities. As for assessment, most CAPT studies relied on human listeners to measure the accurate production of discrete pronunciation features (i.e. segmental and suprasegmental accuracy). Meanwhile, few studies employed global pronunciation learning measures such as intelligibility and comprehensibility. Recommendations for future research are provided based on the discussion of these results.

Compared to previous secondary legislation, Article 11 of the Digital Covid Certificates regulations was remarkably explicit in its requirement for Member States to consider scientific evidence when restricting free movement for the certificate holders. However, we argue in this Article that the regulations achieved a partial codification of the existent case law of the CJEU rather than imposing any additional requirements. Namely, the case law had already required Member States to rely on scientific evidence that reflects the international consensus, that is relevant and up to date, and that the evidence had to demonstrate by means of a risk assessment a real risk to the public health. We also discuss these findings in the light of the proportionality and precautionary principles and suggest that understanding the evolution of the EU legal order’s evidentiary requirements is useful in the light of the legislator’s claim of objective and rational policy-making procedures in public health and other crises.

This study investigates how agents in contested occupations justify and legitimize their work. It examines Immigration and Customs Enforcement (ICE) attorneys who prosecute immigrant removal cases on behalf of the federal government, delving into the narrative strategies that attorneys use to attain self-legitimacy within the agency. While existing literature suggests that self-legitimacy stems from either public support or an intrinsic belief in one’s deservingness of power, this study introduces a third pathway to self-legitimacy, agency entrenchment, in which government prosecutors draw on a highly internalized sense of patriotism and a duty to their organizational role, in the face of heightened public protest and changing administrative priorities. Analyzing forty in-depth interviews with ICE attorneys, this study identifies two primary approaches to agency entrenchment. The first is a bureaucratic approach, in which attorneys derive an internalized sense of duty from the existing law. The second is an enforcement approach, in which attorneys derive moral authority from what they see as their protector status. By deploying these narratives of self-legitimacy, ICE prosecutors attempt to resolve perceived conflicts between their legally mandated responsibilities and the ethical and reputational criticisms they encounter. The findings contribute to the broader understanding of the occupational dynamics between political polarization and law enforcement prosecution.

This article examines how a former Ottoman bureaucrat claimed his retirement pension in interactions with state officials in post-Ottoman Turkey, Syria–Lebanon and Cyprus in the 1920s. Born in Cyprus in 1856 and in Ottoman state service for more than three decades until 1916, Mehmed Ziya had to make renewed efforts to continue receiving his pension until he died in 1936. His troubles were largely due to the need to reconfigure enduring links to the Ottoman state amidst state succession after the First World War. I focus mainly on the diplomatic and administrative correspondence generated by Ziya's initiatives to examine how he sought to address a pressing, quotidian problem. I stress that nationality, as a pivotal category in the reconfiguration of state–subject relations in former imperial domains, played a key role in shaping how Ziya outlived his empire.

Epistemological issues associated with Cantorian set theory were at the center of the foundational debates from 1900 onward. Hermann Weyl, as a central actor, saw this as a smoldering crisis that burst into flames after World War I. The historian Herbert Mehrtens argued that this “foundations crisis” was part of a larger conflict that pitted moderns, led by David Hilbert, against various counter-moderns, who opposed the promotion of set theory and trends toward abstract theories. Among counter-moderns, L.E.J. Brouwer went a step further by proposing new foundational principles based on his philosophy of intuitionism. Meanwhile, Felix Hausdorff emerged as a leading proponent of the new modern style. In this essay, I offer a reassessment of the foundations crisis that stresses the marginal importance of the various intellectual issues involved. Instead, I offer an interpretation that focuses on tensions within the German mathematical community that led to a dramatic power struggle for control of the journal Mathematische Annalen.

In the late 1970s and early 1980s, the terrain of the diplomatic and security landscape of Southern Africa shifted dramatically. South Africa declared various Bantustans “independent,” but they were not recognized by other countries. Small regional states like Lesotho increasingly took more combative diplomatic stances, aided by Cold War connections and, in this case, a local border dispute. This article examines a proposed ski resort that South Africa wanted to build in the QwaQwa Bantustan on Lesotho's border starting in 1975. Because of Lesotho's diplomatic and military escalation, the Khoptjoane resort was never built, but the lengthy dispute contributed to the sidelining of the apartheid regime's diplomats in favor of its securocrats. Thus, we argue the failed ski resort contributed to the atmosphere in which Pretoria greenlit the Maseru Massacre of 1982, presaging the apartheid regime's increased 1980s willingness to use its military superiority against township residents and Southern African neighbors alike.

This article examines how classical music students understand early twentieth-century recordings in higher music education. A qualitative research method was chosen to investigate the beliefs and self-reported practices of 16 students enrolled in a European conservatoire, whose attitudes were considered through the administration of a semi-structured questionnaire and an interview. Their responses identified seven main themes: 1) beliefs, 2) sources, 3) self-reported practices, 4) repertoires/performers, 5) educational implications, 6) limits and 7) benefits.

Results show how much students value early twentieth-century recordings – especially when it comes to analysing the performance practices of the past and developing new interpretations – and how articulate their responses can be with regard to specific stylistic and technical issues. However, possibly due to informal learning strategies and the lack of curricular teaching activities focusing on listening to and analysing recorded interpretations, some responses highlighted a misrepresentation of our recent musical past and the need for a more structured curricular activity. This last should benefit from a vast body of scholarly literature whose relevance is still underestimated among music practitioners.

The analysis of coprolites provides direct evidence of resources consumed and may be paired with ethnographic data to elucidate the dietary and medicinal use of plants in archaeological communities. This article combines and contrasts the macroscopic analysis and DNA metabarcoding of 10 coprolites from Bonneville Estates Rockshelter, Nevada, USA. While the results from both methods confirm previous understandings of subsistence practices at the site, minimal overlap in identified taxa suggests that each accesses different components of the consumed material. The two methods should therefore be seen as complementary and employed together, where possible.

The asymptotic analysis of steady azimuthally invariant electromagnetically driven flows occurring in a shallow annular layer of electrolyte undertaken in Part 1 of this study (McCloughan & Suslov, J. Fluid Mech., vol. 980, 2024, A59) predicted the existence of a two-tori flow state that has not been detected previously. In Part 2 of the study we confirm its existence by numerical time integration of the governing equations. We observe a hysteresis, where the type of solution obtained for the same set of governing parameters depends on the choice of the initial conditions and the way the governing parameters change, which is fully consistent with the analytic results of Part 1. Subsequently, we perform a linear stability analysis of the newly obtained steady state and deduce that the experimentally observed anti-cyclonic free-surface vortices appear on its background as a result of a centrifugal (Rayleigh-type) instability of the interface separating two counter-rotating toroidal structures that form the newly found flow solution. The quantitative characteristics of such instability structures are determined. It is shown that such structures can only exist in sufficiently thin layers with the depth not exceeding a certain critical value.