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John McKay's remarkable insights unveiled a connection between the 'double covers' of the groups of regular polyhedra, known since ancient Greek times, and the exceptional Lie algebras, recognized since the late nineteenth century. The correspondence involves certain diagrams, the ADE diagrams, which can be interpreted in different ways: as quivers associated with the groups, and Dynkin diagrams of root systems of Lie algebras. The ADE diagrams arise in many areas of mathematics, including topics in relativity and string theory, spectral theory of graphs and cluster algebras. Accessible to students, this book explains these connections with exercises and examples throughout. An excellent introduction for students and researchers wishing to learn more about this unifying principle of mathematics.
Online platforms and activities, including smartphones, computers, social media, video games and applications involving artificial intelligence, have become a regular part of daily life and offer individuals a wide range of benefits. The purpose of this document is to increase psychiatrists’ awareness of the frequency and potential risks associated with excessive internet use, and to emphasise the need for psychiatrists to routinely question patients about their online activities. Internet use may become excessive and result in both psychological distress and physical impairments. Treatments and countermeasures may be required to address the harmful consequences of excessive internet use. Psychiatrists should be aware of patient online activities. Understanding of a patient’s online behaviour should now be a routine part of a psychiatric interview.
What are the causes and consequences of North Korea's extended famine of recent years? Though it is not blessed with plentiful arable land or a consistently temperate climate, North Korea has long tried to feed itself and avoid dependence on the outside world. Food security represents, for the government in Pyongyang, a very concrete expression of juche, or self-reliance. Though such a policy has meant that one-third of the population remains rural—a very high percentage for a modern, industrialized country—North Korea continues to push hard to guarantee sufficiency in basic grains.
Marine sedimentary rocks of the late Eocene Pagat Member of the Tanjung Formation in the Asem Asem Basin near Satui, Kalimantan, provide an important geological archive for understanding the paleontological evolution of southern Kalimantan (Indonesian Borneo) in the interval leading up the development of the Central Indo-Pacific marine biodiversity hotspot. In this paper, we describe a moderately diverse assemblage of marine invertebrates within a sedimentological and stratigraphical context. In the studied section, the Pagat Member of the Tanjung Formation records an interval of overall marine transgression and chronicles a transition from the marginal marine and continental siliciclastic succession in the underlying Tambak Member to the carbonate platform succession in the overlying Berai Formation.
The lower part of the Pagat Member contains heterolithic interbedded siliciclastic sandstone and glauconitic shale, with thin bioclastic floatstone and bioclastic rudstone beds. This segues into a calcareous shale succession with common foraminiferal packstone/rudstone lenses interpreted as low-relief biostromes. A diverse trace fossil assemblage occurs primarily in a muddy/glauconitic sandstone, sandy mudstone, and bioclastic packstone/rudstone succession, constraining the depositional setting to a mid-ramp/mid to distal continental shelf setting below fair-weather wave base but above storm wave base.
Each biostrome rests upon a storm-generated ravinement surface characterized by a low-diversity Glossifungites or Trypanites trace fossil assemblage. The erosional surfaces were colonized by organisms that preferred stable substrates, including larger benthic foraminifera, solitary corals, oysters, and serpulid annelid worms.
The biostromes comprised islands of high marine biodiversity on the mud-dominated Pagat coastline. Together, the biostromes analyzed in this study contained 13 genera of symbiont-bearing larger benthic foraminifera, ~40 mollusk taxa, at least 5 brachyuran decapod genera, and 6 coral genera (Anthemiphyllia, Balanophyllia, Caryophyllia, Cycloseris, Trachyphyllia, and Trochocyathus), as well as a variety of bryozoans, serpulids, echinoids, and asterozoans. High foraminiferal and molluscan diversity, coupled with modest coral diversity, supports the hypothesis that the origin of the diverse tropical invertebrate faunas that characterize the modern Indo-Australian region may have occurred in the latest Eocene/earliest Oligocene.
Ultrasound-guided wire localisation may improve intra-operative identification and outcomes of non-palpable cervical lymphadenopathy in a previously treated neck. We undertook a literature search and present our case series to determine the safety and efficacy of ultrasound-guided wire localisation.
Methods
A search of databases up to 29 April 2024 was performed. At our tertiary centre, ultrasound-guided wire localisation was utilised for 20 patients with cervical lymphadenopathy between February 2021 and April 2024.
Results
Seventeen studies with a combined total of 92 patients were identified, with one complication reported. Within our case series, all 20 patients had accurate lesion localisation using ultrasound-guided wire localisation and none required repeat operations.
Conclusion
Ultrasound-guided wire localisation is a safe and cost-effective technique for lesions in an otherwise difficult area to operate, providing confidence to the multidisciplinary team, particularly where histopathology indicates benignity. Surgical outcomes do not appear worse than outcomes without ultrasound-guided wire localisation. We advocate its use provided appropriate patient selection is considered.
Survey researchers increasingly recognize the need to update their gender questions to recognize the existence of transgender and nonbinary people. In this research note, we evaluate changes to the Canadian Election Study (CES) gender questions from 2019 to 2021. Our analyses suggest researchers should add “nonbinary” as a close-ended option and an open-ended response option to gender identity questions. They also suggest that researchers should not include “transgender” in a separate, mutually exclusive response option alongside men and women in gender identity questions but instead identify transgender men and women through a follow-up question. These recommendations can help guide the design of future surveys.
Maladaptive daydreaming is a distinct syndrome in which the main symptom is excessive vivid fantasising that causes clinically significant distress and functional impairment in academic, vocational and social domains. Unlike normal daydreaming, maladaptive daydreaming is persistent, compulsive and detrimental to one’s life. It involves detachment from reality in favour of intense emotional engagement with alternative realities and often includes specific features such as psychomotor stereotypies (e.g. pacing in circles, jumping or shaking one’s hands), mouthing dialogues, facial gestures or enacting fantasy events. Comorbidity is common, but existing disorders do not account for the phenomenology of the symptoms. Whereas non-specific therapy is ineffective, targeted treatment seems promising. Thus, we propose that maladaptive daydreaming be considered a formal syndrome in psychiatric taxonomies, positioned within the dissociative disorders category. Maladaptive daydreaming satisfactorily meets criteria for conceptualisation as a psychiatric syndrome, including reliable discrimination from other disorders and solid interrater agreement. It involves significant dissociative aspects, such as disconnection from perception, behaviour and sense of self, and has some commonalities with but is not subsumed under existing dissociative disorders. Formal recognition of maladaptive daydreaming as a dissociative disorder will encourage awareness of a growing problem and spur theoretical, research and clinical developments.
In this paper we propose and test a contracting mechanism, Multi-Contract Cost Sharing (MCCS), for use in the management of a sequence of projects. The mechanism is intended for situations where (1) the contractor knows more about the true costs of various projects than does the contracting agency (adverse selection), and (2) unobservable effort on the part of the contractor may lead to cost reductions (moral hazard). The proposed process is evaluated in an experimental environment that includes the essential economic features of the NASA process for the acquisition of Space Science Strategic missions. The environment is complex and the optimal mechanism is unknown. The design of the MCCS mechanism is based on the optimal contract for a simpler related environment. We compare the performance of the proposed process to theoretical benchmarks and to an implementation of the current NASA ‘cost cap’ procurement process. The data indicate that the proposed MCCS process generates significantly higher value per dollar spent than using cost caps, because it allocates resources more efficiently among projects and provides greater incentives to engage in cost-reducing innovations.
Inspired by laboratory experiments showing internal waves generated by a plume impinging upon a stratified fluid layer (Ansong & Sutherland. 2010 J. Fluid Mech.648, 405–434), we perform large eddy simulations in three dimensions to examine the structure and source of internal waves emanating from the top of a plume that rises vertically into stratification whose strength ranges over two orders of magnitude between different simulations. Provided the plume is sufficiently energetic to penetrate into the stratified layer, internal waves are generated with frequencies in a relatively narrow band moderately smaller than the buoyancy frequency. Through adaptations of ray theory including viscosity and use of dynamic mode decomposition, we show that the waves originate from within the turbulent flow rather than at the turbulent/non-turbulent interface between the fountain top and the surrounding stratified fluid.
The development of guidelines is time-consuming and cost-intensive. The heterogeneity of clinical practice, evidence, and patients’ needs is an issue across Europe. An European core guidance for a specific psychiatric disorder may help to overcome this issue. Here, we present a progress report on the European Psychiatric Association (EPA) proof-of-concept approach to develop a European consensus guidance on the pharmacological treatment of schizophrenia.
Methods
All national psychiatric associations in Europe were contacted to provide their schizophrenia guidelines. Six guidelines were rated by three experts, experienced in the development of national and international guidelines, from three different countries (Italy, Hungary, and Germany), and the German schizophrenia guideline published in 2019 was found to have the highest quality. For this proof-of-concept approach, 45 recommendations on the pharmacological treatment of schizophrenia from the German guideline were evaluated in a two-step Delphi process to determine their acceptability throughout the European continent.
Results
44 experts participated in the first round and 40 experts in the second round of the Delphi process. Agreement among the involved experts was reached for 75% of the presented recommendations from the German schizophrenia guidelines. 11 out of 45 recommendations (24.4%) did not reach this level of agreement.
Conclusions
This progress report highlights the possibility of developing a pan-European core guidance on the pharmacological treatment of schizophrenia by adapting national guidelines and reconciling their recommendations. However, several barriers in this adaptation process, such as non-agreement in recommendations with strong scientific evidence in the reconciling process, were identified and must be considered when developing the final guidance.
The European Clozapine Task Force is a group of psychiatrists and pharmacologists practicing in 18 countries under European Medicines Agency (EMA) regulation, who are deeply concerned about the underuse of clozapine in European countries. Although clozapine is the most effective antipsychotic for people with treatment-resistant schizophrenia, a large proportion of them do not have access to this treatment. Concerns about clozapine-induced agranulocytosis and stringent blood monitoring rules are major barriers to clozapine prescribing and use. There is a growing body of evidence that the incidence of clozapine-induced agranulocytosis is very low after the first year of treatment. Maintaining lifelong monthly blood monitoring after this period contributes to unjustified discontinuation of clozapine. We leverage recent and replicated evidence on the long-term safety of clozapine to call for the revision and updating of the EMA’s blood monitoring rules, thus aiming to overcome this major barrier to clozapine prescribing and use. We believe the time has come for relaxing the rules without increasing the risks for people using clozapine in Europe.
The association structure between manifest variables arising from the single-factor model is investigated using partial correlations. The additional insights to the practitioner provided by partial correlations for detecting a single-factor model are discussed. The parameter space for the partial correlations is presented, as are the patterns of signs in a matrix containing the partial correlations that are not compatible with a single-factor model.
A special rotation procedure is proposed for the exploratory dynamic factor model for stationary multivariate time series. The rotation procedure applies separately to each univariate component series of a q-variate latent factor series and transforms such a component, initially represented as white noise, into a univariate moving-average. This is accomplished by minimizing a so-called state-space criterion that penalizes deviations of the rotated solution from a generalized state-space model with only instantaneous factor loadings. Alternative criteria are discussed in the closing section. The results of an empirical application are presented in some detail.
Early intervention in psychosis (EIP) services improve outcomes for young people, but approximately 30% disengage.
Aims
To test whether a new motivational engagement intervention would prolong engagement and whether it was cost-effective.
Method
We conducted a multicentre, single-blind, parallel-group, cluster randomised controlled trial involving 20 EIP teams at five UK National Health Service (NHS) sites. Teams were randomised using permuted blocks stratified by NHS trust. Participants were all young people (aged 14–35 years) presenting with a first episode of psychosis between May 2019 and July 2020 (N = 1027). We compared the novel Early Youth Engagement (EYE-2) intervention plus standardised EIP (sEIP) with sEIP alone. The primary outcome was time to disengagement over 12–26 months. Economic outcomes were mental health costs, societal costs and socio-occupational outcomes over 12 months. Assessors were masked to treatment allocation for primary disengagement and cost-effectiveness outcomes. Analysis followed intention-to-treat principles. The trial was registered at ISRCTN51629746.
Results
Disengagement was low at 15.9% overall in standardised stand-alone services. The adjusted hazard ratio for EYE-2 + sEIP (n = 652) versus sEIP alone (n = 375) was 1.07 (95% CI 0.76–1.49; P = 0.713). The health economic evaluation indicated lower mental healthcare costs linked to reductions in unplanned mental healthcare with no compromise of clinical outcomes, as well as some evidence for lower societal costs and more days in education, training, employment and stable accommodation in the EYE-2 group.
Conclusions
We found no evidence that EYE-2 increased time to disengagement, but there was some evidence for its cost-effectiveness. This is the largest study to date reporting positive engagement, health and cost outcomes in a total EIP population sample. Limitations included high loss to follow-up for secondary outcomes and low completion of societal and socio-occupational data. COVID-19 affected fidelity and implementation. Future engagement research should target engagement to those in greatest need, including in-patients and those with socio-occupational goals.
Health Security is a major concern for the Democratic Republic of the Congo (DRC). It is the second largest country in Africa, borders nine other countries, has more than 80 million inhabitants, and has suffered from decades of neglect and conflicts together with multiple recurrent disease outbreaks, including Ebola.
Understanding variations in knowledge and attitudes of psychiatrists to psilocybin therapy is important for the collective discourse about the potential impact on clinical practice and public health in Ireland.
Methods:
A 28-item questionnaire was designed based on previous studies and distributed to psychiatrists in Ireland via online mailing lists and at in-person academic events.
Results:
151 psychiatrists completed the questionnaire (73.3% were under 40 years of age, 76.0% were trainees, and 49.0% were female). In the total sample, 81.5% agreed that psilocybin therapy shows promise in the treatment of psychiatric disorders and 86.8% supported funding research, 86.8% would be willing to refer a patient if it was licensed and indicated, and 78.1% would consider the treatment for themselves, if indicated. Conversely, 6.6% agreed that psilocybin therapy was unsafe even under medical supervision, and 21.9% thought it was potentially addictive. 15.9% of the total sample reported at least one concern including, lack of robust evidence, long-term effectiveness, superiority to current interventions, potential harmful effects, cost and accessibility, and impartiality. Less than half of respondents felt knowledgeable (40.0%) and 9.9% felt adequately prepared to participate in psilocybin therapy. Consultant psychiatrists trended towards less optimism for a potential role in bipolar depression and emotionally unstable personality disorder compared to trainee psychiatrists.
Conclusion:
Overall psychiatrists in Ireland held positive attitudes towards psilocybin therapy. However, there was a lack of knowledge evident. Addressing the knowledge gap and aligning with the best available evidence will be key if psychedelic therapy is to prevail in a clinical setting.
While political scientists regularly engage in spirited theoretical debates about elections and voting behavior, few have noticed that elected politicians also have theories of elections and voting. Here, we investigate politicians’ positions on eight central theoretical debates in the area of elections and voting behavior and compare politicians’ theories to those held by ordinary citizens. Using data from face-to-face interviews with nearly one thousand politicians in 11 countries, together with corresponding surveys of more than twelve thousand citizens, we show that politicians overwhelmingly hold thin, minimalist, “democratic realist” theories of voting, while citizens’ theories are more optimistic and policy oriented. Politicians’ theoretical tendencies—along with their theoretical misalignment from citizens—are remarkably consistent across countries. These theories are likely to have important consequences for how politicians campaign, communicate with the public, think about public policy, and represent their constituents.
To identify changes in hearing loss, tinnitus, vertigo, and migraine in individuals with Ménière’s disease diagnosed with coronavirus disease 2019 and during the UK national lockdown.
Method
Patients were questioned regarding coronavirus disease 2019 status and how their symptoms of hearing loss, tinnitus, vertigo, and migraine changed because of the pandemic. Of the 411 participants recruited into this study, 382 had a self-reported coronavirus disease 2019 status.
Results
Of those individuals with a positive coronavirus disease 2019 diagnosis, 43 (11.3 per cent) were more likely to experience worsening symptoms of hearing loss and tinnitus. Worsening symptoms of hearing loss and tinnitus, but improved symptoms related to vertigo, were observed during the UK national lockdown.
Conclusion
A diagnosis of coronavirus disease 2019 and/or experiencing the consequences of a national lockdown potentially resulted in a worsening of hearing loss and tinnitus symptoms. Symptoms of vertigo were found to have improved during the same period.
We use large-eddy simulations to study the penetration of a buoyant plume carrying a passive tracer into a stably stratified layer with constant buoyancy frequency. Using a buoyancy-tracer volume distribution, we develop a method for objectively partitioning plume fluid in buoyancy-tracer space into three regions, each of which corresponds to a coherent region in physical space. Specifically, we identify a source region where undiluted plume fluid enters the stratified layer, a transport region where much of the transition from undiluted to mixed fluid occurs in the plume cap and an accumulation region corresponding to a radially spreading intrusion. This method enables quantification of different measures of turbulence and mixing within each of the three regions, including potential energy and turbulent kinetic energy dissipation rates, an activity parameter and the instantaneous mixing efficiency. We find that the most intense buoyancy gradients lie in a thin layer at the cap of the penetrating plume. This provides the primary stage of mixing between plume and environment and exhibits a mixing efficiency around 50 %. Newly generated mixtures of environmental and plume fluid join the intrusion and experience relatively weak turbulence and buoyancy gradients. As the intrusion spreads radially, environmental fluid surrounding the intrusion is mixed into the intrusion with moderate mixing efficiency. This dominates the volume of environmental fluid entrained into the region containing plume fluid. However, the ‘strongest’ entrainment, as measured by the specific entrainment rate, is largest in the plume cap, where the most buoyant environmental fluid is entrained.