To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
We study density and partition properties of polynomial equations in prime variables. We consider equations of the form $a_1h(x_1) + \cdots + a_sh(x_s)=b$, where the ai and b are fixed coefficients and h is an arbitrary integer polynomial of degree d. We establish that the natural necessary conditions for this equation to have a monochromatic non-constant solution with respect to any finite colouring of the prime numbers are also sufficient when the equation has at least $(1+o(1))d^2$ variables. We similarly characterize when such equations admit solutions over any set of primes with positive relative upper density. In both cases, we obtain lower bounds for the number of monochromatic or dense solutions in primes that are of the correct order of magnitude. Our main new ingredient is a uniform lower bound on the cardinality of a prime polynomial Bohr set.
The COVID-19 pandemic has impacted patient’s visits to general practitioners (GPs). However, it is unclear what the impact of COVID-19 has been on the interaction among the local primary care clinics, the GP Department within the hospital and specialists.
Methods:
The interaction among GPs referring to hospital-based specialists and specialists to local doctors was determined, comparing pre-pandemic 2019 and 2020 during the pandemic.
Results:
Reduced referrals from GPs to specialists were consistent with the reduction in specialist referrals back to the local doctors, which dropped by approximately 50% in 2020, particularly in the two most common chronic conditions (hypertension and diabetes mellitus).
Discussion:
Reduced referral of patients from local clinics to Tongren Hospital is probably due to the extensive online training provided to the local GPs to become more competent in handling local patients via telehealth. Our data provide some insight to assist in combatting the pandemic of COVID-19, offering objective evidence of the impact of COVID-19 on patient management by GPs.
Parrots (Psittaciformes) are widely kept in captivity, yet their welfare is under-researched in comparison to other captive species. This study aimed to determine key welfare issues affecting parrots through a modified Delphi approach. Twenty-eight welfare issues were first compiled via a preliminary literature review. Parrot welfare experts and sector professionals (n = 26) were then recruited to participate in an online survey to rank the identified welfare issues on a six-point scale according to severity, duration and prevalence of each issue. Participants could provide commentary on their ranking and propose additional welfare issues of concern. Items with a mean score of 4 or above progressed to a second survey, where participants (n = 14) indicated whether they agreed or disagreed with the current ranking of the welfare issue. Finally, two online workshops were held, where participants (n = 7) discussed the rankings from the second survey and sought to establish a consensus on the top ten welfare issues in each category and overall. Six of the seven final participants agreed with the final rankings, achieving a consensus rate of 86%. The top welfare issues overall were lack of owner knowledge and support; social isolation; housing; environmental opportunity to express behaviours; nutrition; development of normal behaviour; lack of a ‘life plan’ for birds; abnormal behaviours; lack of parrot-specific veterinary training; and insufficient application and enforcement of legislation. It is hoped that identification and recognition of these priority areas will be useful in directing future efforts in research, owner and veterinary education, and policy initiatives to improve parrot welfare.
This article identifies four frames of corruption in the discourse of three leaders of Operation Lava Jato, also known in English as Operation Car Wash, a large-scale Brazilian anticorruption operation (2014–2021). These frames are inequality, hidden pact, backwardness, and chronic disease. The frames were identified by analyzing a wide set of press interviews, opinion articles, and books by two prosecutors and one judge whose work has revealed scandals involving the state oil company Petrobras. The operation had a major impact on politics and the economy and left a controversial legacy. We noticed a contradiction between one frame invoking judicial activism (inequality) and three frames focusing on specific techniques that appeal to a more conventional view on the judiciary’s role (hidden pact, backwardness, and chronic disease). Furthermore, even when scholars were still largely positive about the operation, the discourse showed signs of judicial activism. This analysis contributes to the debate on Lava Jato and judicial activism by focusing on discourse rather than action.
Ayahuasca is a botanical hallucinogen traditionally used for therapeutic and ritual purposes by indigenous groups from Northwestern Amazonian countries such as Brazil, Peru, Colombia, and Ecuador. Ayahuasca is made by the decoction of two plants, which are rich in the 5-HT1A/2A partial agonist dimethyltryptamine or DMT (from the leaves of the Psychotria viridis bush) and β-carbolines such as harmine, from the stalks of the Banisteriopsis caapi vine. There is an increasing interest in the possible therapeutic effects of ayahuasca, especially for psychiatric disorders (major depression, posttraumatic stress disorder, and substance use disorder). This review summarizes information on the pharmacology, safety, and therapeutic potentials of ayahuasca. Although human experimental and naturalist studies published until now suggest a good safety and tolerability profile, often associated with improvements in depressive and anxious symptoms, there are few controlled studies, with small sample sizes, using only single doses, and with short follow-ups. Potential benefits of ayahuasca should be evaluated in larger samples in both experimental and observational studies and using different doses in controlled trials.
This article delves into the historical trajectory of Lotta Femminista, a pioneering separatist feminist network in Italy during the early 1970s, and its significant influence on feminist discourse, particularly concerning the advocacy for wages for housework. Through an examination of the group's development within the broader context of the Italian women's movement, this study illuminates the theoretical foundations and practical activism associated with the perspective on wages for housework. Drawing on archival documents and personal accounts, the essay investigates how Lotta Femminista depicted domestic labour as a form of women's exploitation within a Marxist framework. Despite facing criticism and opposition, Lotta Femminista's ideas resonated globally, leaving a legacy in feminist theory and activism. Through its engagement with issues such as the refusal to work and the recognition of unpaid care as a site of capitalist exploitation, Lotta Femminista contributed to the broader history of feminism in Italy and beyond.
We identify a class of smooth Banach *-algebras that are differential subalgebras of commutative C*-algebras whose openness of multiplication is completely determined by the topological stable rank of the target C*-algebra. We then show that group algebras of Abelian groups of unbounded exponent fail to have uniformly open convolution. Finally, we completely characterize in the complex case (uniform) openness of multiplication in algebras of continuous functions in terms of the covering dimension.
Lassa fever (LF) virus (LASV) is endemic in Sierra Leone (SL) and poses a significant public health threat to the region; however, no risk factors for clinical LF have been reported in SL. The objective of this study was to identify the risk factors for clinical LF in an endemic community in SL. We conducted a case–control study by enrolling 37 laboratory-confirmed LF cases identified through the national LF surveillance system in SL and 140 controls resided within a one-kilometre radius of the case household. We performed a conditional multiple logistic regression analysis to identify the risk factors for clinical LF. Of the 37 cases enrolled, 23 died (62% case fatality rate). Cases were younger than controls (19.5 years vs 28.9 years, p < 0.05) and more frequently female (64.8% vs 52.8%). Compared to the controls, clinical LF cases had higher contact with rodents (rats or mice) in their households in the preceding three weeks (83.8% vs 47.8%). Households with a cat reported a lower presence of rodents (73% vs 38%, p < 0.01) and contributed to a lower rate of clinical LF (48.6% vs 55.7%) although not statistically significant (p = 0.56). The presence of rodents in the households (matched adjusted odds ratio (mAOR): 11.1) and younger age (mAOR: 0.99) were independently associated with clinical LF.
Rodent access to households and younger age were independently associated with clinical LF. Rodent access to households is likely a key risk factor for clinical LF in rural SL and potentially in other countries within the West African region. Implementing measures to control rodents and their access to households could potentially decrease the number of clinical LF cases in rural SL and West Africa.
The depth-integrated horizontal momentum equations and continuity equation are employed to develop a new model. The vertical velocity and pressure can be expressed exactly in terms of horizontal velocities and free-surface elevation, which are the only unknowns in the model. Dividing the water column into elements and approximating horizontal velocities using linear shape function in each element, a set of model equations for horizontal velocities at element nodes is derived by adopting the weighted residual method. These model equations can be applied for transient or steady free-surface flows by prescribing appropriate lateral boundary conditions and initial conditions. Here, only the wave–current–bathymetry interaction problems are investigated. Theoretical analyses are conducted to examine various linear wave properties of the new models, which outperform the Green–Naghdi-type models for the range of water depth to wavelength ratios and the Boussinesq-type models as they are capable of simulating vertically sheared currents. One-dimensional horizontal numerical models, using a finite-difference method, are applied to a wide range of wave–current–bathymetry problems. Numerical validations are performed for nonlinear Stokes wave and bichromatic wave group propagation in deep water, sideband instability, regular wave transformation over a submerged shoal and focusing wave group interacting with linearly sheared currents in deep water. Very good agreements are observed between numerical results and laboratory data. Lastly, numerical experiments of wave shoaling from deep to shallow water are conducted to further demonstrate the capability of the new model.
How international law applies to the use of information and communications technology by States is still a matter of discussion. Against this background, cyberspace has become the main area of competition between States, and this competition, to put it simply, is resulting in a constant low-intensity warfare below the threshold for a use of force. Such low-intensity cyber warfare, from a legal point of view, revitalizes the debate over the concept of a “state of intermediacy” that has the potential to overcome the dichotomy between peace and war. In the present author's opinion, this state of intermediacy also supports the idea that the international humanitarian law (IHL) principle of distinction should be applied, even before the eruption of a full-scale war, whenever wartime means and capabilities are employed by States. This paper argues that some opacities in international law have created favourable conditions for such constant low-intensity warfare, and that tackling the identified opacities would therefore be beneficial in order to achieve a more peaceful cyberspace. Thus, the paper goes on to address one of the identified opacities, namely the definition of espionage under international law, because, as international law now stands, it does not allow us to tackle the other identified opacities. Finally, the paper discusses how the proposed narrow interpretation of espionage can cope with the IHL principle of distinction in the cyber domain.
Previous research in the evolutionary and psychological sciences has suggested that markers or tags of ethnic or group membership may help to solve cooperation and coordination problems. Cheating remains, however, a problem for these views, insofar as it is possible to fake the tag. While evolutionary psychologists have suggested that humans evolved the propensity to overcome this free rider problem, it is unclear how this module might manifest at the group level. In this study, we investigate the degree to which native and non-native speakers of accents – which are candidates for tags of group membership – spoken in the UK and Ireland can detect mimicry. We find that people are, overall, better than chance at detecting mimicry, and secondly we find substantial inter-group heterogeneity, suggesting that cultural evolutionary processes drive the manifestations of cheater detection. We discuss alternative explanations and suggest avenues of further inquiry.
For a partially specified stochastic matrix, we consider the problem of completing it so as to minimize Kemeny’s constant. We prove that for any partially specified stochastic matrix for which the problem is well defined, there is a minimizing completion that is as sparse as possible. We also find the minimum value of Kemeny’s constant in two special cases: when the diagonal has been specified and when all specified entries lie in a common row.
Populist radical right (PRR) parties' attacks against prevailing historical interpretations have received much public attention because they question the foundations of countries' political orders. Yet, how prominent are such attacks and what characterizes their sentiment and content? This article proposes an integrated mixed-methods approach to investigate the prominence, sentiment, and interpretations of history in PRR politicians' parliamentary speeches. Studying the case of Germany, we conducted a quantitative analysis of national parliamentary speeches (2017–2021), combined with a qualitative analysis of all speeches made by Alternative for Germany (AfD) in 2017–2018. The AfD does not use historical markers more prominently but is distinctly less negative when speaking about history compared to its general political language. The collocation and qualitative analyses reveal the nuanced ways in which the AfD affirms and disavows various mnemonic traditions, underlining the PRR's complex engagement with established norms.
This paper describes four methodological proposals for rescuing from oblivion and highlighting women writers in Graeco-Roman Antiquity. In workshops employing a variety of active methodologies, students become acquainted with Greek writers like Sappho, Diotima of Mantinea and Aspasia, and their Roman counterparts, including Sulpicia and Agrippina the Younger, while also becoming aware of the authorship of these women writers and their lack of visibility. The proposals take the shape of activities aimed at fostering a vocation for science among baccalaureate students in Spain but can also be easily adapted to secondary and even higher education in other educational contexts.
The Ice-sheet and Sea-level System Model (ISSM) provides numerical solutions for ice sheet dynamics using finite element and fine mesh adaption. However, considering ISSM is compatible only with central processing units (CPUs), it has limitations in economizing computational time to explore the linkage between climate forcings and ice dynamics. Although several deep learning emulators using graphic processing units (GPUs) have been proposed to accelerate ice sheet modeling, most of them rely on convolutional neural networks (CNNs) designed for regular grids. Since they are not appropriate for the irregular meshes of ISSM, we use a graph convolutional network (GCN) to replicate the adapted mesh structures of the ISSM. When applied to transient simulations of the Pine Island Glacier (PIG), Antarctica, the GCN successfully reproduces ice thickness and velocity with a correlation coefficient of approximately 0.997, outperforming non-graph models, including fully convolutional network (FCN) and multi-layer perceptron (MLP). Compared to the fixed-resolution approach of the FCN, the flexible-resolution structure of the GCN accurately captures detailed ice dynamics in fast-ice regions. By leveraging 60–100 times faster computational time of the GPU-based GCN emulator, we efficiently examine the impacts of basal melting rates on the ice sheet dynamics in the PIG.
Coffee berry diseases (CBD) pose significant threats to coffee production worldwide, affecting the livelihoods of millions of farmers and the global coffee market. Fractional calculus provides a powerful framework for describing non-local and memory-dependent phenomena, making it suitable for modelling the long-range interactions inherent in CBD spread. This study aims to formulate and analyse fractional order model for CBD transmission dynamics in the sense of Atangana–Baleanu–Caputo. Fixed point theorems were utilised to test the existence and uniqueness of the model’s solutions using fractional order. The basic reproduction number was calculated utilising the next-generation matrix. The model has locally asymptotically stable equilibrium positions (disease-free and endemic). Furthermore, the Lyapunov function was used to conduct a global stability analysis of the equilibrium locations. A numerical simulation of the CBD model was created using the fractional Adam–Bashforth–Moulton approach to validate the analytical findings. Our findings contribute to the development of more accurate predictive models and inform the design of targeted interventions to mitigate the impact of CBD on coffee production systems.
This article examines the topic of postcolonial subject formation in the work of Moroccan historian and theorist Abdallah Laroui (1933–) by analyzing his evaluation of the notion of authenticity. I trace understandings of self-identity for Moroccans and other Arab populations that Laroui articulates in his work from the 1960s through the 2000s, and situate his interventions in relation both to relevant political developments and to contributions of other Arab intellectuals on this question, across this time period. Rather than interpret Laroui as a proponent of undifferentiated universalism in his reading of modern history, as many of his critics and commentators do, I demonstrate how he departs from such an approach by calling attention to the notion of particularism, which he defends as a counterpoint to authenticity. The article concludes with a discussion of Laroui's abandonment of a positive, alternative conception of cultural and political subjectivity by the late twentieth century, and considers what the implications of this shift in his thought are.
We study a skew product transformation associated to an irrational rotation of the circle $[0,1]/\sim $. This skew product keeps track of the number of times an orbit of the rotation lands in the two complementary intervals of $\{0,1/2\}$ in the circle. We show that under certain conditions on the continued fraction expansion of the irrational number defining the rotation, the skew product transformation has certain dense orbits. This is in spite of the presence of numerous non-dense orbits. We use this to construct laminations on infinite type surfaces with exotic properties. In particular, we show that for every infinite type surface with an isolated planar end, there is an infinite clique of $2$-filling rays based at that end. These $2$-filling rays are relevant to Bavard and Walker’s loop graphs.
Several publications and web-based tools are available in weed science literature to help weed scientists to carry out basic analysis of dose-response studies. Given the nature of the complicated relationship between the explanatory variable (dose as x-axis) evaluated against response variables of interest (y-axis), using regression curves should be the preferred method for handling data analysis. The objective of this manuscript is to provide user-friendly instructions for conducting and analyzing several types of dose-response studies that were lacking in current weed science literature. A better understanding of less commonly used concepts of hormesis and toxicological safety thresholds (no-observable-adverse-effect-level [NOAEL] and lowest-observable-adverse-effect-level [LOAEL]) is needed to help address the potential risks and benefits associated with herbicide use while minimizing environmental impacts. Basic codes available in cost-free R software are provided for data analysis and to foster collaboration among weed scientists.