6,729 research outputs found

    Numerical Assessment of Infragravity Swash Response to Offshore Wave Frequency Spread Variability

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    We use a numerical model, already validated for this purpose, to simulate the effect of wave frequency spread on wave transformation and swash amplitudes. Simulations are performed for planar beach slope cases and for offshore wave spectra whose frequency spread changes over realistic values. Results indicate that frequency spread, under normally approaching waves, affects swash amplitudes. For moderately dissipative conditions, the significant infragravity swash increases for increasing values of the offshore frequency spread. The opposite occurs under extremely dissipative conditions. The numerical analysis suggests that this inverted pattern is driven by the effect that different distributions of incoming long?wave energy have on low?frequency wave propagation and dissipation. In fact, with large frequency spreads, wave groups force relatively short subharmonic waves that are strongly enhanced in the shoaling zone. This process leads to an infragravity swash increase for increasing frequency spread under moderately dissipative conditions in which low?frequency energy dissipation in shallow water is negligible or small. However, under extremely dissipative conditions, the significant low?frequency energy dissipation associated with large frequency spreads overturns the strong energy growth in the shoaling zone eventually yielding an infragravity swash decrease for increasing frequency spread.This work has been funded under (1) the RETOS INVESTIGACION 2014 (Grant BIA2014-59718-R) program of the Spanish Ministry of Economy and Competitiveness and (2) the NEPTUNE 2 project, L. R. 7/2007 by Regione Autonoma della Sardegna

    Sensing the heat: Climate change vulnerability and foreign direct investment inflows

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    We investigate whether climate change vulnerability determines foreign direct investment (FDI) inflows. We reason that multinational firms foresee a higher climate change vulnerability of host-country a locational disadvantage while making FDI allocation decisions. Utilizing annual data from 152 countries spanning the period 1996–2019 and employing the panel pooled ordinary least square regressions, we evidence that FDI inflows are lower in countries more vulnerable to climate change. We also observe that FDI inflows are only sensitive to climate-related risks in high- and middle-income countries, but not in low-income countries where the market size is a primary driver of FDI inflows. Moreover, we also find that host countries may weaken the adverse effects of climate change vulnerability on FDI inflows by strengthening the economic, institutional, and social environment

    Where energy flows, passion grows: testing a moderated mediation model of work passion through a cross-cultural lens

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    This study examines how and when passionate leaders can instigate work passion in their followers. We propose relational energy as a social interaction mediator that can facilitate the crossover of work passion from leader to followers. Additionally, we introduce a moderator of culture (Anglo culture, e.g., Canada vs. Confucian Asian culture, e.g., China) as it plays a vital role in the dynamics of interpersonal relations within a leader-follower dyad. We collected two-wave data from MBA students of two Confucian Asian countries (China and Singapore, n = 120) and two Anglo countries (Canada and Australia, n = 265) to test our moderated mediation model. The results show that interactions with passionate leaders can generate relational energy in followers and subsequently lead to followers’ passion for work. Furthermore, the findings shed light on the moderating effect of culture, such that the leader-follower work passion relationship via follower relational energy was stronger for followers from Anglo culture than the followers from Confucian Asian culture. Limitations of the study and directions for future research are discussed

    Surface van der Waals Forces in a Nutshell

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    Most often in chemical physics, long range van der Waals surface interactions are approximated by the exact asymptotic result at vanishing distance, the well known additive approximation of London dispersion forces due to Hamaker. However, the description of retardation effects that is known since the time of Casimir is completely neglected for lack of a tractable expression. Here we show that it is possible to describe surface van der Waals forces at arbitrary distances in one single simple equation. The result captures the long sought crossover from non-retarded (London) to retarded (Casimir) interactions, the effect of polarization in condensed media and the full suppression of retarded interactions at large distance. This is achieved with similar accuracy and the same material properties that are used to approximate the Hamaker constant in conventional applications. The results show that at ambient temperature, retardation effects significantly change the power law exponent of the conventional Hamaker result for distances of just a few nanometers.Comment: 6 pages + 4 figures + supplementary materia

    SEVERAL NEW INTEGRAL INEQUALITIES VIA K-RIEMANN–LIOUVILLE FRACTIONAL INTEGRALS OPERATORS

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    The main objective of this paper is to establish several new integral inequalities including k-Riemann – Liouville fractional integrals for convex, s-Godunova – Levin convex functions, quasiconvex, η-quasi-convex. In order to obtain our results, we have used classical inequalities as H¨older inequality, Power mean inequality and Weighted H¨older inequality. We also give some applications

    Outreach obstetrics training in Western Australia improves neonatal outcome and decreases caesarean sections

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    The objective of this study was to determine the effect of a multi-professional outreach obstetric training programme on perinatal and neonatal outcomes. This was a retrospective comparison of 5-min low Apgar scores, stillbirth, perinatal death and moderate/severe hypoxic ischaemic encephalopathy rates in 127,753 infants born in Western Australia before and after the introduction of training in rural and remote areas. Following the introduction of the training programme, there was a highly significant (p0.003) decrease in the rate of infants born with low 5-min Apgar scores (from 20.4 to 15.4/1,000 live births). While the changes in the other three outcomes were not significant, all three demonstrated a trend for improvement in the intervention area. This is the second study of an educational intervention in obstetrics to demonstrate improvement in neonatal outcome and the first to be associated with a decrease in caesarean sections

    Discrete breathers in honeycomb Fermi-Pasta-Ulam lattices

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    We consider the two-dimensional Fermi-Pasta-Ulam lattice with hexagonal honeycomb symmetry, which is a Hamiltonian system describing the evolution of a scalar-valued quantity subject to nearest neighbour interactions. Using multiple-scale analysis we reduce the governing lattice equations to a nonlinear Schrodinger (NLS) equation coupled to a second equation for an accompanying slow mode. Two cases in which the latter equation can be solved and so the system decoupled are considered in more detail: firstly, in the case of a symmetric potential, we derive the form of moving breathers. We find an ellipticity criterion for the wavenumbers of the carrier wave, together with asymptotic estimates for the breather energy. The minimum energy threshold depends on the wavenumber of the breather. We find that this threshold is locally maximised by stationary breathers. Secondly, for an asymmetric potential we find stationary breathers, which, even with a quadratic nonlinearity generate no second harmonic component in the breather. Plots of all our findings show clear hexagonal symmetry as we would expect from our lattice structure. Finally, we compare the properties of stationary breathers in the square, triangular and honeycomb lattices
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