Scalar Transformations Research Articles

Cluster analysis of Model for End-stage Liver Disease and European System for Cardiac Operative Risk Evaluation for predicting operative mortality after concomitant tricuspid valve surgery

ObjectivePatients requiring concomitant tricuspid surgery represent a heterogeneous cohort with significant comorbidities and varying degrees of organ and right ventricular dysfunction. However, surgeons can rely on little beyond intuition and experience when discussing operative risks. The objective of the study is to assess how the Model for End-stage Liver Disease score complements the European System for Cardiac Operative Risk Evaluation II in risk assessment. MethodsWe performed a single-center retrospective cohort study of 369 consecutive patients who underwent concomitant tricuspid valve surgery from 2011 to 2020. Multivariate analysis of factors affecting operative mortality was performed, producing 2 multivariate risk prediction models, one consisting of European System for Cardiac Operative Risk Evaluation II components and the other consisting of both European System for Cardiac Operative Risk Evaluation II components and Model for End-stage Liver Disease. The models were compared by measuring c-statistic using the Hanley-McNeil method. This was further evaluated with category-free net reclassification improvement index. K-means clustering was performed using Model for End-stage Liver Disease and European System for Cardiac Operative Risk Evaluation II values after scalar transformation as independent variables and operative mortality as the dependent variable. ResultsThe Model for End-stage Liver Disease is an independent predictor of operative mortality, with an adjusted odds ratio of 1.286 per point. Inclusion of the Model for End-stage Liver Disease improves the discriminatory power of the European System for Cardiac Operative Risk Evaluation II for operative mortality, with a difference in area under the curve of 0.128 [0.0341-0.222] (P = .0076). The net reclassification improvement index of incorporating Model for End-stage Liver Disease with European System for Cardiac Operative Risk Evaluation II was 0.959 [0.515-1.392], indicating significant improvement in risk reclassification. Cluster analysis identified a unique cohort of patients with intermediate-to-high Model for End-stage Liver Disease, not previously identified with European System for Cardiac Operative Risk Evaluation II alone, who experienced high operative mortality. ConclusionsModel for End-stage Liver Disease score as a quantifier of hepatorenal dysfunction complements European System for Cardiac Operative Risk Evaluation II in predicting operative mortality after tricuspid valve surgery.

Low complexity beamforming design in reconfigurable intelligent surface-assisted communication systems

Due to the possibility of blockage during communication, the communication quality may be poor. Therefore, Reconfigurable Intelligent Surface (RIS) technology can effectively solve this problem. In order to increase the capacity of RIS-assisted wireless communication systems, joint optimization of beamforming design is crucial. However, the complexity of the optimization algorithm increases with the increase in the number of base station antennas and RIS elements deployed. Therefore, we propose a joint low-complexity optimization beamforming design based on fractional programming (FP) to address this issue. Specifically, we first use perfect channel state information to maximize the system's sum rate, as this problem is non-convex, we decompose the original problem into three sub-problems, and then introduce appropriate auxiliary variables. We derive optimal closed-form solutions for active and passive beamforming types, respectively. As the optimal solution obtained leads to higher computational complexity with an increase in the number of base station antennas and RIS elements, we reduce the computational complexity of obtaining the optimal solution based on the Woodbury transformation and scalar transformation. The proposed algorithm is also extended to the case where there is channel state information error. Finally, simulation results show that the proposed algorithm has certain advantages over other algorithms.

Urban agglomeration, glocalisation, and the governance of scalar transformation in the global south: a case study from Cape Town, South Africa

AbstractIn theorising the rapid expansion of urban agglomeration across the world, a significant body of work has examined the transformation of scale from the perspective of geographical size and the regulatory facets of devolved power. A further literature has examined what are seen as the relational dimensions in the transformation and constitution of space and the extent to which these are socially constructed. In this conceptualisation, scale is constituted and reconstituted by capitalist relations of production, social production, and consumption. The influence of capitalist relations on scale has most explicitly been illustrated by the impact of globalisation and the way it has served to weaken the regulatory powers of nation states and is simultaneously reordering the hierarchy of government power within them. Metropolitan governments have been exposed to global markets and to the influence of transnational corporations and, in a process of glocalisation, increasingly endeavour to create an entrepreneurial environment conducive to attract and retain foreign investment. Hitherto the interpenetration of the global and local has largely been studied in the context of urban agglomeration and scalar transformation in the global North. In an attempt to address this lacuna this article examines the manifestation of the process of glocalisation in metropolitan Cape Town in South Africa in the global South. It posits that the municipal government’s ambition to transform the city into a modern digitally based economy linked to global markets manifests many of the characteristics of glocalisation. Furthermore, it argues, far from promoting greater social inclusion in a highly unequal post-apartheid city, the economic model which has been adopted is exacerbating social inequality and poverty.

Scale(s) of Sexuate Difference

Technofeminism has long known that it must be a multi-scalar feminism, that is, able to think, encounter, and negotiate these increasing scales of complexity that comprise our world, from the pharmacological to the planetary-computational. We read technofeminism as constitutively defined by its commitment to both realism and anti-essentialism, and contemporary technofeminisms to be epitomised by, on the one hand, the flat vitalist ontology of new materialism, and on the other, the trans-scalar rationalism of Xenofeminism. By examining these contemporary technofeminisms through contemporary theorisations of the concept of scale, we show that they have a problem with what the latter identify as ‘scalar collapse’; these technofeminisms conceptualise the multi-scalarity of reality, in the last instance, via a collapse into either the ‘master scale’ of new materialist ‘matter’, or via the ‘trans-scalar zoom’ of Xenofeminist rationalism. As such, they recoil from the reality of scalar differences, undermining their commitment to realism (and therefore technics), as well as reducing scalar difference to one unitary, ‘metaphysical’ ground, placing them back within an essentialist collapse. Through examining contemporary theorisations of scale, we claim that in order to avoid such scalar collapse, any truly multi-scalar theory must think difference as both ontogenetic, in the Simondonian sense, and irreducibly at-least-two, in the sense of Irigaray’s concept of sexuate difference. Against any concerns that Irigaray’s notion of sexuate difference may be essentialist or determinist, we show that the ontogenetic character of this difference means it is irreducible and yet also open-ended, that is, open to multiply complex, topologically scalar transformations throughout subsequent individuations. It is this thinking of difference as this ontogenetic ‘at least two’ that can enable contemporary technofeminisms to be truly multi-scalar feminisms.

Time-fractional Davey–Stewartson equation: Lie point symmetries, similarity reductions, conservation laws and traveling wave solutions

As a celebrated nonlinear water wave equation, the Davey–Stewartson equation is widely studied by researchers, especially in the field of mathematical physics. On the basis of the Riemann–Liouville fractional derivative, the time-fractional Davey–Stewartson equation is investigated in this paper. By application of the Lie symmetry analysis approach, the Lie point symmetries and symmetry groups are obtained. At the same time, the similarity reductions are derived. Furthermore, the equation is converted to a system of fractional partial differential equations and a system of fractional ordinary differential equations in the sense of Riemann–Liouville fractional derivative. By virtue of the symmetry corresponding to the scalar transformation, the equation is converted to a system of fractional ordinary differential equations in the sense of Erdélyi–Kober fractional integro-differential operators. By using Noether’s theorem and Ibragimov’s new conservation theorem, the conserved vectors and the conservation laws are derived. Finally, the traveling wave solutions are achieved and plotted.

Mining and the scalar transformations of the state in the Democratic Republic of Congo

AbstractThis article reflects on the effects of the recent mining boom on the (trans-)formation of the state in D.R. Congo. To do so, it proposes to integrate macro- and micro- approaches to the political economy of mining into a broader analysis of the power practices of actors at different levels of the state apparatus. Taking the copper mining sector as a case study, it explores the various means by which the presidency, provincial authorities and customary chiefs have drawn resources from mining in the period from the early 2000s to the present. This analysis highlights the various resources that state actors at different levels use to assert their authority over foreign mining companies. From a broader perspective, it shows that, although the liberalisation of the mining sector has opened up new revenue opportunities for all these actors, it has not resulted in a significant power redistribution between them.

Sectoral versus environmental scales: implementing river continuity restoration and river basin approach in areas of production

In the context of Water Framework Directive (WFD) and the objective of ''good ecological status'' of European water bodies, both the idea of river continuity restoration and the river basin approach call for a scalar transformation of water governance based on ecological principles. Among the WFD literature, very few have focused on industrial actors in areas of production and their role implementing or countering these principles. To observe this, it is argued that one must first grasp the sectoral scales linked to economic actors’ practices. We define sectoral scales as the scalar issues related to industries practices and then question how they have been challenged by new environmental scalar configurations. Using case study analysis, this article focus on two industries in southwestern France in the Adour-Garonne hydrographic District, namely hydropower and irrigated agriculture. The results highlight that implementing river continuity restoration and river basin approach challenge the economic and political practices of these industries related to the spatial scope of their production process and their political jurisdiction. In the face of change, industrial actors defend “functional” perimeters for their activities by rescaling water governance in order to keep control over water resources and maintain the institutional arrangements they have forged within those boundaries. In conclusion, we suggest that research on changes of scales relating to water governance should further question economic actors and how their practices are ultimately entangled in specific scales. Only in so doing can we understand deep-rooted obstacles to the implementation of the WFD in areas of production and better grasp social and ecological interdependencies at stake.

Similarity Solutions to Nonlinear Diffusion/Harry Dym Fractional Equations

By using scalar similarity transformation, nonlinear model of time-fractional diffusion/Harry Dym equation is transformed to corresponding ordinary fractional differential equations, from which a travelling-wave similarity solution of time-fractional Harry Dym equation is presented. Furthermore, numerical solutions of time-fractional diffusion equation are discussed. Again, through another similarity transformation, nonlinear model of space-fractional diffusion/Harry Dym equation is turned into corresponding ordinary differential equations, whose two similarity solutions are also worked out.

Relative Versus Absolute Commodity Measurements in Benefit Transfer: Consequences for Validity and Reliability

Non‐market goods can be measured on cardinal or relative scales. Consider a marsh of 200 acres, of which 20 acres would be affected by a policy. The same affected area can be measured in cardinal terms (20 acres) or as a relative proportion (10% of the marsh). When relative units such as percentages are a scalar transformation of cardinal units, the units of measurement used for modeling are often inconsequential for single‐site econometric and welfare analysis. However, this seemingly inconsequential transformation can have significant implications for benefit transfer across sites—a simple observation that remains unacknowledged by the literature. This article provides a theoretical and empirical evaluation of variable measurement conventions within benefit transfer, deriving conditions under which different types of measurement scales are expected to enhance validity and reliability. Theoretical results are illustrated using an application of discrete choice experiments to coastal flood adaptation in two Connecticut (United States) communities. Empirical findings validate expectations from the theoretical model, suggesting that transfers over goods measured in relative units may often outperform transfers over goods measured in cardinal units. These findings imply that the outcome of benefit transfer convergent validity tests may hinge on whether goods are measured in cardinal or relative units.

A high-dimensional spatial rank test for two-sample location problems

In high-dimensional situations, the traditional multivariate sign- or rank-based procedures for the two-sample location testing problems are ineffective, since in the construction of the test statistics, the scatter matrix to be inverted is singular. To solve this problem, many high-dimensional spatial sign or rank tests have been proposed, some of which are very efficient. However, most of these existing tests no longer work in very high dimensional situations, which only allows the dimension of variables to be the square of the sample sizes at most, hence are restrictive for practical applications. On this ground, a new high-dimensional spatial rank test is proposed in this paper, which is invariant under scalar transformations, maintains the efficiency advantage of spatial-rank-based testing methods, and could even allow the dimension to grow almost exponentially with the sample sizes. The theoretical results of the proposed test are established, followed by some convincing numerical results and two real data analyses.

From the particle pair production to the Hawking–Unruh radiation in the maximal acceleration hypothesis

Starting from a nonstandard approach to the Unruh effect, we present a description of the emission of radiation from a black hole that avoids quantization of scalar fields and Bogoliubov transformations, but assumes the existence of a maximal acceleration. In this framework, the description appears closer to the original heuristic Hawking’s point of view, with respect to the standard scenario.

Upon solutions to the transonic plane-parallel gas flows

Some similarity solutions of the time-fractional stationary transonic plane-parallel gas flows (STPPGF) and their generalized space-fractional nonlinear system are obtained by using scalar similarity transformations, including traveling-wave similarity solutions. Two approximated solution formulas of the obtained ordinary fractional differential equations for the generalized space-fractional nonlinear system are generated as well. Finally, a class of approximated solutions of the time-fractional nonlinear system of STPPGF with initial-boundary-value conditions are produced by applying the separated variable method.

Similarity solutions and the computation formulas of a nonlinear fractional-order generalized heat equation

A generalized nonlinear heat equation with the fractional derivative is proposed, whose similarity solutions are derived from a type of special scalar transformation with two parameters. With the help of separated variable method, two special series solutions of the standard heat equation are obtained. Finally, through computation of the left Riemann–Liouville fractional derivative, we obtain two approximated computation formulas of the factional-order ordinary differential equation which could be used to calculate the numerical solutions of the generalized nonlinear heat conduction equation.

Scalar asymptotic charges and dual large gauge transformations

In recent years soft factorization theorems in scattering amplitudes have been reinterpreted as conservation laws of asymptotic charges. In gauge, gravity, and higher spin theories the asymptotic charges can be understood as canonical generators of large gauge symmetries. Such a symmetry interpretation has been so far missing for scalar soft theorems. We remedy this situation by treating the massless scalar field in terms of a dual two-form gauge field. We show that the asymptotic charges associated to the scalar soft theorem can be understood as generators of large gauge transformations of the dual two-form field.The dual picture introduces two new puzzles: the charges have very unexpected Poisson brackets with the fields, and the monopole term does not always have a dual gauge transformation interpretation. We find analogues of these two properties in the Kramers-Wannier duality on a finite lattice, indicating that the free scalar theory has new edge modes at infinity that canonically commute with all the bulk degrees of freedom.

Bayesian inference for partially identified smooth convex models

This paper proposes novel Bayesian procedures for partially identified models when the identified set is convex with a smooth boundary, whose support function is locally smooth with respect to the data distribution. Using the posterior of the identified set, we construct Bayesian credible sets for the identified set, the partially identified parameter and their scalar transformations. These constructions, based on the support function, benefit from several computationally attractive algorithms when the identified set is convex, and are proved to have valid large sample frequentist coverages. These results are based on a local linear expansion of the support function of the identified set. We provide primitive conditions to verify such an expansion.

A Test on the Multivariate Behrens–Fisher Problem in High–Dimensional Data by Block Covariance Estimation

In this paper, we proposed a new testing statistic for testing the equality of mean vectors from two multivariate normal populations when the covariance matrices are unknown and unequal in high–dimensional data. A new test is proposed based on the idea of keeping more information from the sample covariance matrices as much as possible. A proposed test is invariant under scalar transformations and location shifts. We showed that the asymptotic distribution of proposed statistic is standard normal distribution when number of random variables approach infinity. We also compared the performance of the proposed test with other three existing tests by the simulation study. The simulation results showed that the attained significance level of proposed test close to setting nominal significance level satisfactorily. The attained power of proposed test outperforms as the other comparative tests under form of covariance matrices considered which can be arranged to block diagonal matrix structure. The attained power becomes more powerful when the dimension increases for a given sample size or vice versa, or relationship level between random variables in each sample increases. Finally, the proposed test is also illustrated with an analysis of DNA microarray data.

Metaplasticity and the boundaries of social cognition: exploring scalar transformations in social interaction and intersubjectivity

Through the application of Material Engagement Theory (MET) to enactivist analyses of social cognition, this paper seeks to examine the role of material culture in shaping the development of intersubjectivity and long-term scalar transformations in social interaction. The deep history of human sociality reveals a capacity for communities to self-organise at radically emergent scales across a variety of temporal and spatial ranges. This ability to generate and participate in heterogenous, multiscalar relationships and identities demonstrates the developmental plasticity of human intersubjectivity. Perhaps human sociality’s most unique feature is this intersubjective plasticity, that is, the ability for diverse collectivities of individuals and groups to adopt and transition between numerous social identities and behaviours with profound rapidity and flexibility. However, the most influential models in the study of social cognition, the Social Intelligence Hypothesis and Theory of Mind, promote a view of intersubjectivity that is rooted in methodological individualism and primarily understood as a capacity for observation and prediction. This approach leads to significant issues when confronted with the diversity and plasticity of hominin social organisation, particularly in regards to the computational burdens and information processing bottlenecks such scalar changes imply for cognitivist models. This paper examines the metaphysical assumptions in computational models of the mind that result in representational apriorism and an epiphenomenal treatment of material culture that hinder our understanding of the evolution and development of social cognition. Specifically, this article critiques the logics of computation, information processing, representationalism, and content within Neo-Darwinian frameworks that obscure and distort the interrelationships of evolutionary, developmental, ecological and cultural processes. Through a synthesis of material engagement and enactivist approaches to social cognition, this article argues that it is possible to explain the emergent and multiscalar dynamics of hominin sociality in terms of ecologically distributed and developmentally plastic interactions between brains, bodies and material culture.

“Communications from Below”: Scalar Transformations in Richard Flanagan's <em>The Narrow Road to the Deep North</em> (2013) and Steven Carroll's <em>A World of Other People</em> (2013)

“Communications from Below”: Scalar Transformations in Richard Flanagan's <em>The Narrow Road to the Deep North</em> (2013) and Steven Carroll's <em>A World of Other People</em> (2013)

A new nonparametric test for high-dimensional regression coefficients

ABSTRACTSeveral tests for high-dimensional (large p, small n) regression coefficients have been proposed in the recent literature, but they are adversely affected by outlying observations and heavy-tailed distributions. In order to attack these challenges, a novel nonparametric testing procedure is developed under the framework of rank-based inference and is robust with respect to both the responses and the covariates. Besides, the proposed test statistic is invariant under the group of scalar transformations, which implies that our test statistic can integrate all the individual information in a relatively fair way. The newly defined test has many desirable general asymptotic properties, such as normality and consistency when We assess the finite-sample performance of the proposed test by examining its size and power via Monte Carlo simulation, which demonstrates an improvement over the previous literature.

Scaling the mobility of health workers in an enlarged Europe: An open political-economy perspective

The enlargement of the European Union in 2004 and 2007 and the marketisation of health care are increasing the mobility of workers and driving a scalar transformation of the sector across Europe. Drawing on questionnaires and interviews in 17 European Union countries, and focusing on two case study New Member States, we analyse inter- and intra-country drivers and impacts of health care labour mobility. The data are analysed from an open political-economy perspective underpinned by an understanding of scale as a socially constructed material entity mediated by national and supranational state institutions, and the collective agency of workers. We emphasise the contradictory and contested nature of rescaling health care and the complex micro-dynamics of mobility. Although absolute outward migration across borders is relatively small, the movement of health care specialists is having a disproportionate effect on sender countries and regions within them.