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How are congressional party leaders chosen? In the first comprehensive study since Robert Peabody's classic Leadership in Congress, political scientists Matthew Green and Douglas Harris draw on newly collected data about U.S. House members who have sought leadership positions from the 1960s to the present - data including whip tallies, public and private vote commitments, interviews, and media accounts - to provide new insights into how the selection process truly works. Elections for congressional party leaders are conventionally seen as a function of either legislators' ideological preferences or factors too idiosyncratic to permit systematic analysis. Analyzing six decades' worth of information, Green and Harris find evidence for a new comprehensive model of vote choice in House leadership elections that incorporates both legislators' goals and their connections with leadership candidates. This study will stand for years to come as the definitive treatment of a crucial aspects of American politics.

Brazil's national health system has developed and rapidly scaled up an approach to primary care that relies on lay community health agents and interdisciplinary care teams to provide universal access to proactive first-contact care and public health interventions. Brazil has made rapid progress toward universal coverage of its population through its national health system, the Sistema Único de Saúde (SUS). Since its emergence from dictatorship in 1985, Brazil — which has the world's fifth-largest population and seventh-largest economy — has invested substantially in expanding access to health care for all citizens, a goal that is implicit in the Brazilian constitution and the principles guiding the national health system. 1 The SUS comprises public and private health care institutions and providers, financed primarily through taxes with contributions from federal, state, and municipal budgets. Health care management is decentralized, and municipalities . . .

Similar protocols are already in place and used by CHWs in diverse settings—eg, as part of the Integrated Management of Newborn and Childhood Illness.5 Additionally, home visits for vulnerable people would allow CHWs to assess whether individuals have adequate supplies of food and medicines for long-term conditions, are aware of basic hygiene precautions, and whether they have mental health problems. Marco Di Lauro/Stringer/Getty Images Entry criteria could include occupations that provide basic training in first aid or assessing medical emergencies, such as flight attendants, or registration on a health professional training programme. CHWs in Brazil have been established for many years, are well integrated into their communities, and provide a wide range of health and social care support activities to each of the 100–150 households that they are responsible for. [...]in Brazil, additional roles for preventing the spread of and supporting those infected with COVID-19 or in self-isolation could be integrated into the work of CHWs.

The topic of this paper is a two-player zero-sum differential game known as the target guarding problem. After a brief review of Isaacs’ original problem and solution, a problem with second-order dynamics and acceleration control is considered. It is shown that there are four solution classes satisfying the necessary conditions. The four classes are (i) abnormal and non-singular, (ii) normal and non-singular, (iii) normal and pursuer singular, (iv) normal and evader singular. The normal and totally singular case is ruled out. Closed-form solutions are provided for cases ii–iv. The order of singularity in all cases is infinite. Thus, the problem exhibits many interesting properties: normality, abnormality, non-singularity, infinite-order singularity, and non-uniqueness. A practical example of each class is provided.

The scaling relationship between the size of an appendage or organ and that of the body as a whole is tightly regulated during animal development. If a structure grows at a different rate than the rest of the body, this process is termed allometric growth. The zebrafish another longfin (alf) mutant shows allometric growth resulting in proportionally enlarged fins and barbels. We took advantage of this mutant to study the regulation of size in vertebrates. Here, we show that alf mutants carry gain-of-function mutations in kcnk5b, a gene encoding a two-pore domain potassium (K(+)) channel. Electrophysiological analysis in Xenopus oocytes reveals that these mutations cause an increase in K(+) conductance of the channel and lead to hyperpolarization of the cell. Further, somatic transgenesis experiments indicate that kcnk5b acts locally within the mesenchyme of fins and barbels to specify appendage size. Finally, we show that the channel requires the ability to conduct K(+) ions to increase the size of these structures. Our results provide evidence for a role of bioelectric signaling through K(+) channels in the regulation of allometric scaling and coordination of growth in the zebrafish.

Abstract The quest to map the genetic foundations of phenotypes has been empowered by the modern diversity, quality, and availability of genomic resources. Despite these expanding resources, the abundance of variation within lineages makes it challenging to associate genetic change to specific phenotypes, without an a priori means of isolating the changes from background genomic variation. Evolution provides this means through convergence—that is, the shared variation that may result from replicate evolutionary experiments across independent trait occurrences. To leverage these opportunities, we developed TRACCER: Topologically Ranked Analysis of Convergence via Comparative Evolutionary Rates. Compared to current methods, this software empowers rate convergence analysis by factoring in topological relationships, because genetic variation between phylogenetically proximate trait changes is more likely to be facilitating the trait. Comparisons are performed not with singular branches, but with the complete paths to the most recent common ancestor for each pair of lineages. This ensures that comparisons represent a single context diverging over the same timeframe while obviating the problematic requirement of assigning ancestral states. We applied TRACCER to two case studies: mammalian transitions to marine environments, an unambiguous collection of traits that have independently evolved three times; and the evolution of mammalian longevity, a less delineated trait but with more instances to compare. By factoring in topology, TRACCER identifies highly significant, convergent genetic signals, with important incongruities and statistical resolution when compared to existing approaches. These improvements in sensitivity and specificity of convergence analysis generate refined targets for downstream validation and identification of genotype–phenotype relationships.

Background The status of randomised controlled trials (RCTs) as the ‘gold standard’ for evaluating efficacy in healthcare interventions is increasingly debated among the research community, due to often insufficient consideration for implementation. Normalisation Process Theory (NPT), which focuses on the work required to embed processes into practice, offers a potentially useful framework for addressing these concerns. While the theory has been deployed in numerous RCTs to date, more work is needed to consolidate understanding of if, and how, NPT may aid implementation planning and processes within RCTs. Therefore, this review seeks to understand how NPT contributes to understanding the dynamics of implementation processes within RCTs. Specifically, this review will identify and characterise NPT operationalisation, benefits and reported challenges and limitations in RCTs. Methods A qualitative systematic review with narrative synthesis of peer-reviewed journal articles from eight databases was conducted. Studies were eligible for inclusion if they reported sufficient detail on the use of NPT within RCTs in a healthcare domain. A pre-specified data extraction template was developed based on the research questions of this review. A narrative synthesis was performed to identify recurrent findings. Results Searches identified 48 articles reporting 42 studies eligible for inclusion. Findings suggest that NPT is primarily operationalised prospectively during the data collection stage, with limited sub-construct utilisation overall. NPT is beneficial in understanding implementation processes by aiding the identification and analysis of key factors, such as understanding intervention fidelity in real-world settings. Nearly three-quarters of studies failed to report the challenges and limitations of utilising NPT, though coding difficulties and data falling outside the NPT framework are most common. Conclusions NPT appears to be a consistent and generalisable framework for explaining the dynamics of implementation processes within RCTs. However, operationalisation of the theory to its full extent is necessary to improve its use in practice, as it is currently deployed in varying capacities. Recommendations for future research include investigation of NPT alongside other frameworks, as well as earlier operationalisation and greater use of NPT sub-constructs. Trial Registration The protocol for this systematic review was accepted for public registration on PROSPERO (registration number: CRD42022345427) on 26 July 2022.

A liquid–liquid transition (LLT) is a transformation from one liquid to another through a first-order transition. The LLT is fundamental to the understanding of the liquid state and has been reported in a few materials such as silicon, phosphorus, triphenyl phosphite, and water. Furthermore, it has been suggested that the unique properties of materials such as water, which is critical for life on the planet, are linked to the existence of the LLT. However, the experimental evidence for the existence of an LLT in many molecular liquids remains controversial, due to the prevalence and high propensity of the materials to crystallize. Here, we show evidence of an LLT in a glass-forming trihexyltetradecylphosphonium borohydride ionic liquid that shows no tendency to crystallize under normal laboratory conditions. We observe a step-like increase in the static dielectric permittivity at the transition. Furthermore, the sizes of nonpolar local domains and ion-coordination numbers deduced from wide-angle X-ray scattering also change abruptly at the LLT. We independently corroborate these changes in local organization using Raman spectroscopy. The experimental access to the evolution of local order and structural dynamics across a liquid–liquid transition opens up unprecedented possibilities to understand the nature of the liquid state.