Search results

A regression kink design (RKD or RK design) can be used to identify casual effects in settings where the regressor of interest is a kinked function of an assignment variable. In this chapter, we apply an RKD approach to study the effect of unemployment benefits on the duration of joblessness in Austria, and discuss implementation issues that may arise in similar settings, including the use of bandwidth selection algorithms and bias-correction procedures. Although recent developments in nonparametric estimation (Calonico, Cattaneo, & Farrell, 2014; Imbens & Kalyanaraman, 2012) are sometimes interpreted by practitioners as pointing to a default estimation procedure, we show that in any given application different procedures may perform better or worse. In particular, Monte Carlo simulations based on data-generating processes that closely resemble the data from our application show that some asymptotically dominant procedures may actually perform worse than “sub-optimal” alternatives in a given empirical application.

Much scholarly examination of BDSM and kink attempts to make meaningful various specific practices as cultural “texts,” and analyzes them for what they might signify within a particular culture or subculture. This approach has often focused on interpreting specific acts in relation to human sexuality or psychology – specifically deviance – or on critiquing them from a feminist perspective. I propose to approach an examination of (a particular) BDSM (event) itself as (a) performance, and I argue that it is not only performance but that it is performative, creating a liminal space within the already liminal space of the fetish club in which it occurs. This “kink-space” then becomes the place within which the embodiment, and the dissolution, of binaries occurs, creating possibilities for the audience and upending the structures upon which identity is based. Ultimately, BDSM as performance is an avenue for the understanding of the concepts of liminality and power and how they function to create and contain selves.

This paper aims to study the breather, lump-kink and interaction solutions of a (3 + 1)-dimensional generalized shallow water waves (GSWW) equation, which describes water waves propagating in the ocean or is used for simulating weather.

Hirota bilinear form and the direct method are used to construct breather and lump-kink solutions of the GSWW equation. The “rational-cosh-cos-type” test function is applied to obtain three kinds of interaction solutions.

The fusion and fission of the interaction solutions between a lump wave and a 1-kink soliton of the GSWW equation are studied. The dynamics of three kinds of interaction solutions between lump, kink and periodic waves are discussed graphically.

This paper studies the breather, lump-kink and interaction solutions of the GSWW equation by using various approaches and provides some phenomena that have not been studied.

The purpose of this paper is to determine both analytically and numerically the kink solutions to a new one-dimensional, viscoelastic generalization of Burgers’ equation, which includes a non-linear constitutive law, and the number of kinks as functions of the non-linearity and relaxation parameters.

An analytical procedure and two explicit finite difference methods based on first-order accurate approximations to the first-order derivatives are used to determine the single- and double-kink solutions.

It is shown that only two parameters characterize the solution and that the existence of a shock wave requires that the (semi-positive) relaxation parameter be less than unity and the non-linearity parameter be less than two. It is also shown that negative values of the non-linearity parameter result in kinks with a single inflection point and strain and dissipation rates with a single relative minimum and a single, relative maximum, respectively. For non-linearity parameters between one and two, it is shown that the kink has three inflection points that merge into a single one as this parameter approaches one and that the strain and dissipation rates exhibit relative maxima and minima whose magnitudes decrease and increase as the relaxation and nonlinearity coefficients, respectively, are increased. It is also shown that the viscoelastic generalization of the Burgers equation presented here is related to an ϕ⁸−scalar field.

A new, one-dimensional, viscoelastic generalization of Burgers’ equation, which includes a non-linear constitutive law and relaxation is proposed, and its kink solutions are determined both analytically and numerically. The equation and its solutions are connected with scalar field theories and may be used to both studies the effects of the non-linearity and relaxation and assess the accuracy of numerical methods for first-order, non-linear partial differential equations.

South African public debt has recently increased significantly and has reached worrying levels. This study aims to examine the debt threshold effects on economic growth in South Africa, with an objective of suggesting a debt threshold as South African policymakers will seek to reduce debt to a sustainable level in the coming years.

The study applies a recent novel methodology advanced by Hansen (2017) that allows modelling a regression kink with an unknown threshold.

The findings of this study indicate a robust debt threshold of 37% of gross domestic product (GDP). Below this threshold, debt is growth-enhancing, but above 37% of GDP, debt is harmful to growth in South Africa.

Among other things, to reduce the debt-to-GDP ratio, South Africa will need a fiscal consolidation policy by undertaking reforms to state-owned companies to reduce their reliance on public funds, as well as putting in place economic measures to boost long-term growth. The country should also improve tax collection in order to realize additional tax revenue through enhancing compliance and other revenue collection measures.

Most of the existing studies on debt threshold effects in Africa are panel data studies, which assume parameter homogeneity, by determining a single debt threshold value applicable to all countries. This can be misleading as the debt-growth nexus is country-specific, being conditional on several factors, such as institutional quality. The present study applies a recent novel methodology, which allows to model a regression kink with an unknown threshold, for the case of South Africa. The methodology endogenously determines the debt threshold while also allowing a country-specific analysis.

This paper seeks to explain various aspects of labour market activity under oligopsonistic conditions by means of a kinked labour supply curve, the development of which appears to have been neglected in the literature. The ideas for this approach arose out of an ongoing empirical study of a large local labour market during which it became apparent that an extension of the case stated by Bronfenbrenner (1940) could be used to account for a wide range of observed behaviour. It is apparent that dominant employers can dictate conditions in the market even in situations where their concentration of employment is as low as 15–30% of total employment, and at this level one would expect the incidence and effect of oligopsony to be significant within the economy as a whole. Major labour market studies in the U.K. (MacKay et al 1971) and the U.S.A. (Rees and Shultz, 1970) have tended to ignore the consequences of employer interdependence, basically because they were centred on large conurbations. This is an area that may fruitfully be more extensively explored.

The purpose of this paper is to reveal the dynamical behavior of higher dimensional nonlinear wave by searching for the multi-wave solutions to the (3+1)-D Jimbo-Miwa equation.

The authors apply bilinear form and extended homoclinic test approach to the (3+1)-D Jimbo-Miwa equation.

In this paper, by using bilinear form and extended homoclinic test approach, the authors obtain new cross-kink multi-soliton solutions of the (3+1)-dimensional Jimbo-Miwa equation, including the periodic breathertype of kink three-soliton solutions, the cross-kink four-soliton solutions, the doubly periodic breather-type of soliton solutions and the doubly periodic breather-type of cross-kink two-soliton solutions. It is shown that the extended homoclinic test approach, with the help of symbolic computation, provides an effective and powerful mathematical tool for solving higher dimensional nonlinear evolution equations in mathematical physics.

The research manifests that the structures of the solution to higher dimensional nonlinear equations are diversified and complicated.

The methods used in this paper can be widely applied to the research of spatial and temporal characteristics of nonlinear equations in physics and engineering technology. These methods are also conducive for people to know objective laws and grasp the essential features of the development of the world.

The purpose of this paper is to find solutions for the (2+1)-dimensional B-type Kadomtsev-Petviashvili equation and to research the quality of B-type Kadomtsev-Petviashvili equation.

The authors apply the extended three-wave approach and the homoclinic test technique to solve the B-type Kadomtsev-Petviashvili equation.

The authors obtain breather type of cross-kink solutions, doubly breather type of kink solitary solutions and the breather type of kink wave solutions for B-type Kadomtsev-Petviashvili equation.

As nonlinear evolution equations are characterized by rich dynamical behaviors, the authors have just found some of them and others are still to be found.

These results may help us to investigate the local structure and the interaction of waves in high-dimensional models.