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As countries transition from fossil fuels to renewable energy, impacts on wildlife, particularly avian species, have become a concern. In Kenya, the effects of human-made infrastructure such as power lines and wind turbines on birds have been overlooked. To prevent further loss of biodiversity, it is necessary for infrastructure development policies to consider these impacts on birds. We aim to identify gaps in current policies by analysing the intersection of wildlife conservation and power-line infrastructure development in Kenya. Through content analysis, we evaluate the effectiveness of existing wildlife protection and energy-related policies and identify strengths and weaknesses to highlight areas for improvement. Our analysis reveals that current policies neglect threats posed by power lines and other infrastructure to birds. This oversight points to challenges such as a lack of awareness among policymakers and stakeholders and a lack of legal obligation for energy institutions to implement mitigation measures; conservationists may also face conflicts with those responsible for electricity distribution. Addressing these policy gaps is essential for effective wildlife conservation and sustainable development. This paper underscores the need to integrate wildlife conservation considerations into energy infrastructure planning to mitigate adverse impacts on avian species.
We prove that any bounded degree regular graph with sufficiently strong spectral expansion contains an induced path of linear length. This is the first such result for expanders, strengthening an analogous result in the random setting by Draganić, Glock, and Krivelevich. More generally, we find long induced paths in sparse graphs that satisfy a mild upper-uniformity edge-distribution condition.
An examination of the apparent gap – familiar in many branches of philosophy – between ‘the facts’ and ‘values’, focusing especially on Sam Gamgee’s perception of ‘Earendil’s Star’ and the real nature of ‘the planet Venus’: Is it possible to trust in the awe and admiration we may feel towards ‘the heavens’ in the light of current astronomical theory about the wider world? How can humane values, including love of beauty, survive in an inhumanly indifferent world? Can obvious fictions have more than allegorical significance? Must we rely on fictions to survive as humane creatures, or may those seeming fictions, and our initial emotional response, provide true guidance to the way things are, and how we might be?
The study applies a two-dimensional adaptive mesh refinement (AMR) method to estimate the coordinates of the locations of the centre of vortices in steady, incompressible flow around a square cylinder placed within a channel. The AMR method is robust and low cost, and can be applied to any incompressible fluid flow. The considered channel has a blockage ratio of $1/8$. The AMR is tested on eight cases, considering flows with different Reynolds numbers ($5\le Re\le 50$), and the estimated coordinates of the location of the centres of vortices are reported. For all test cases, the initial coarse meshes are refined four times, and the results are in good agreement with the literature where a very fine mesh was used. Furthermore, this study shows that the AMR method can capture the location of the centre of vortices within the fourth refined cells, and further confirms an improvement in the estimation with more refinements.
In response to the complex and challenging task of long-distance inspection of small-diameter and variable-diameter mine holes, this paper presents a design for an adaptive small-sized mine hole robot. First, focusing on the environment of small-diameter mine holes, the paper analyzes the robot’s functions and overall structural framework. A two-wheeled wall-pressing robot with good mobility, arranged in a straight line, is designed. Furthermore, an adaptive variable-diameter method is devised, which involves constructing an adaptive variable-diameter model and proposing a control method based on position and force estimators, enabling the robot to perceive external forces. Lastly, to verify the feasibility of the structural design and adaptive variable-diameter method, performance tests and analyses are conducted on the robot’s mobility and adaptive variable-diameter capabilities. Experimental results demonstrate that the robot can move within small-diameter mine holes at any inclination angle, with a maximum horizontal crawling speed of 3.96 m/min. By employing the adaptive variable-diameter method, the robot can smoothly navigate convex platform obstacles and slope obstacles in mine holes with diameters ranging from 70 mm to 100 mm, achieving the function of adaptive variable-diameter within 2 s. Thus, it can meet the requirements of moving inside mine holes under complex conditions such as steep slopes and small and variable diameters.
Zonal flows are mean flows in the east–west direction, which are ubiquitous on planets, and can be formed through ‘zonostrophic instability’: within turbulence or random waves, a weak large-scale zonal flow can grow exponentially to become prominent. In this paper, we study the statistical behaviour of the zonostrophic instability and the effect of magnetic fields. We use a stochastic white noise forcing to drive random waves, and study the growth of a mean flow in this random system. The dispersion relation for the growth rate of the expectation of the mean flow is derived, and properties of the instability are discussed. In the limits of weak and strong magnetic diffusivity, the dispersion relation reduces to manageable expressions, which provide clear insights into the effect of the magnetic field and scaling laws for the threshold of instability. The magnetic field mainly plays a stabilising role and thus impedes the formation of the zonal flow, but under certain conditions it can also have destabilising effects. Numerical simulation of the stochastic flow is performed to confirm the theory. Results indicate that the magnetic field can significantly increase the randomness of the zonal flow. It is found that the zonal flow of an individual realisation may behave very differently from the expectation. For weak magnetic diffusivity and moderate magnetic field strengths, this leads to considerable variation of the outcome, that is whether zonostrophic instability takes place or not in individual realisations.
We study the problem of identifying a small number $k\sim n^\theta$, $0\lt \theta \lt 1$, of infected individuals within a large population of size $n$ by testing groups of individuals simultaneously. All tests are conducted concurrently. The goal is to minimise the total number of tests required. In this paper, we make the (realistic) assumption that tests are noisy, that is, that a group that contains an infected individual may return a negative test result or one that does not contain an infected individual may return a positive test result with a certain probability. The noise need not be symmetric. We develop an algorithm called SPARC that correctly identifies the set of infected individuals up to $o(k)$ errors with high probability with the asymptotically minimum number of tests. Additionally, we develop an algorithm called SPEX that exactly identifies the set of infected individuals w.h.p. with a number of tests that match the information-theoretic lower bound for the constant column design, a powerful and well-studied test design.
Food systems in Africa are under pressure from climate change, conflicts, health pandemics such as COVID-19 and rising food prices. The COVID-19 pandemic highlighted weaknesses in global food systems and indeed Africa’s was not spared. Although COVID-19 mortality and morbidity in Africa were relatively low in comparison to other regions, the containment measures employed by countries amplified a rather dire situation. Disruptions were seen in livelihoods, food value chains, increases in food prices and loss of income. These changes affected access to nutritious foods. A resilient food system that can withstand and recover from disruption and shocks will be important for ensuring access to healthy diets for all. This review paper assesses the state of food insecurity and malnutrition situation pre-COVID-19 and the impact of COVID-19 on Africa’s food systems and access to healthy diet. To put Africa on a path to accelerated recovery, a resilient and sustainable food system will be crucial. The following recommendations are made: (i) increasing agriculture productivity, with special attention to the foods that contribute to healthy diets – fruits and vegetables, and animal source foods (ii) promoting the production and consumption of nutritious African traditional and indigenous foods (iii) transforming Africa’s food systems to be gender-sensitive (iv) investing in well-targeted social protection programmes (v) supporting food environments that protect healthy diets and (vi) employing data and information to monitor food systems transformation.
Emotion regulation, as a typical “top-down” emotional self-regulation, has been shown to play an important role in children’s oppositional defiant disorder (ODD) development. However, the association between other self-regulation subcomponents and the ODD symptom network remains unclear. Meanwhile, while there are gender differences in both self-regulation and ODD, few studies have examined whether their relation is moderated by gender. Five hundred and four children (age 6–11 years; 207 girls) were recruited from schools with parents and classroom teachers completing questionnaires and were followed up for assessment six months later. Using moderation network analysis, we analyzed the relation between self-regulation and ODD symptoms, and the moderating role of gender. Self-regulation including emotion regulation, self-control, and emotion lability/negativity had broad bidirectional relations with ODD symptoms. In particular, the bidirectional relations between emotion regulation and ODD3 (Defies) and between emotion lability/negativity and ODD4 (Annoys) were significantly weaker in girls than in boys. Considering the important role of different self-regulation subcomponents in the ODD symptom network, ODD is better conceptualized as a self-regulation disorder. Each ODD symptom is associated with different degrees of impaired “bottom-up” and “top-down” self-regulation, and several of the associations vary by gender.
This article examines the information sharing behavior of U.S. politicians and the mass public by mapping the ideological sharing space of political news on social media. As data, we use the near-universal currency of online information exchange: web links. We introduce a methodological approach and software to unify the measurement of ideology across social media platforms by using sharing data to jointly estimate the ideology of news media organizations, politicians, and the mass public. Empirically, we show that (1) politicians who share ideologically polarized content share, by far, the most political news and commentary and (2) that the less competitive elections are, the more likely politicians are to share polarized information. These results demonstrate that news and commentary shared by politicians come from a highly unrepresentative set of ideologically extreme legislators and that decreases in election pressures (e.g., by gerrymandering) may encourage polarized sharing behavior.