Spectral quantification of nonlinear behaviour of the nearshore seabed and correlations with potential forcings at Duck, N.C., U.S.A

Local bathymetric quasi-periodic patterns of oscillation are identified from monthly profile surveys taken at two shore-perpendicular transects at the USACE field research facility in Duck, North Carolina, USA, spanning 24.5 years and covering the swash and surf zones. The chosen transects are the two furthest (north and south) from the pier located at the study site. Research at Duck has traditionally focused on one or more of these transects as the effects of the pier are least at these locations. The patterns are identified using singular spectrum analysis (SSA). Possible correlations with potential forcing mechanisms are discussed by 1) doing an SSA with same parameter settings to independently identify the quasi-periodic cycles embedded within three potentially linked sequences: monthly wave heights (MWH), monthly mean water levels (MWL) and the large scale atmospheric index known as the North Atlantic Oscillation (NAO) and 2) comparing the patterns within MWH, MWL and NAO to the local bathymetric patterns. The results agree well with previous patterns identified using wavelets and confirm the highly nonstationary behaviour of beach levels at Duck; the discussion of potential correlations with hydrodynamic and atmospheric phenomena is a new contribution. The study is then extended to all measured bathymetric profiles, covering an area of 1100m (alongshore) by 440m (cross-shore), to 1) analyse linear correlations between the bathymetry and the potential forcings using multivariate empirical orthogonal functions (MEOF) and linear correlation analysis and 2) identify which collective quasi-periodic bathymetric patterns are correlated with those within MWH, MWL or NAO, based on a (nonlinear) multichannel singular spectrum analysis (MSSA). (...continued in submitted paper)Comment: 50 pages, 3 tables, 8 figure

Selection system orientations as an explanation for the differences between dual leaders of the same organization in their perception of organizational performance

We investigate to what extent individual managers operating in a dual leadership structure have different perceptions of how well his/her organization is performing. Using selection system theory we develop hypotheses on the relationships between a leader's selection system orientation and his/her perception of performance along multiple dimensions: market performance, expert performance and peer performance. The hypotheses are tested using dyadic data from 59 organizations in the performing arts led by two-hierarchically equivalent-managers. Our results show that dual leaders' differences in terms of market orientation and expert orientation relate positively to perceived performance differences along the same dimensions. This relationship is not found with respect to peer selection orientation. Generally, the relationship between orientation differences and perceived performance differences is stronger if the process of interpreting signals to construct a perception of organizational performance leaves more room for equivocality and uncertainty