Observations of core‐mantle boundary Stoneley modes

Core‐mantle boundary (CMB) Stoneley modes represent a unique class of normal modes with extremely strong sensitivity to wave speed and density variations in the D” region. We measure splitting functions of eight CMB Stoneley modes using modal spectra from 93 events with M w > 7.4 between 1976 and 2011. The obtained splitting function maps correlate well with the predicted splitting calculated for S20RTS+Crust5.1 structure and the distribution of S diff and P diff travel time anomalies, suggesting that they are robust. We illustrate how our new CMB Stoneley mode splitting functions can be used to estimate density variations in the Earth's lowermost mantle. Key Points We present CMB Stoneley mode splitting function measurements The CMB Stoneley mode splitting correlates well with diffracted body wave data Our measurements allow to constrain density variations in the lowermost mantlePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99080/1/figS2_plot_prem_freq_Q_stoneley_paperrotated.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/99080/2/grl50514.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/99080/3/figS1_plot_coef_stoneley_paper_deg2_newrotated.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/99080/4/README_suppl_mat_GRL.pd

Comparing ray-theoretical and finite-frequency teleseismic traveltimes:Implications for constraining the ratio of S-wave to P-wave velocity variations in the lower mantle

A number of seismological studies have indicated that the ratio R of S-wave and P-wave velocity perturbations increases to 3–4 in the lower mantle with the highest values in the large low-velocity provinces (LLVPs) beneath Africa and the central Pacific. Traveltime constraints on R are based primarily on ray-theoretical modelling of delay times of P waves (ΔTP) and S waves (ΔTS), even for measurements derived from long-period waveforms and core-diffracted waves for which ray theory (RT) is deemed inaccurate. Along with a published set of traveltime delays, we compare predicted values of ΔTP, ΔTS, and the ΔTS/ΔTP ratio for RT and finite-frequency (FF) theory to determine the resolvability of R in the lower mantle. We determine the FF predictions of ΔTP and ΔTS using cross-correlation methods applied to spectral-element method waveforms, analogous to the analysis of recorded waveforms, and by integration using FF sensitivity kernels. Our calculations indicate that RT and FF predict a similar variation of the ΔTS/ΔTP ratio when R increases linearly with depth in the mantle. However, variations of R in relatively thin layers ( 20 s). This is because FF predicts that ΔTP and ΔTS vary smoothly with epicentral distance even when vertical P-wave and S-wave gradients change abruptly. Our waveform simulations also show that the estimate of R for the Pacific LLVP is strongly affected by velocity structure shallower in the mantle. If R increases with depth in the mantle, which appears to be a robust inference, the acceleration of P waves in the lithosphere beneath eastern North America and the high-velocity Farallon anomaly negates the P-wave deceleration in the LLVP. This results in a ΔTP of about 0, whereas ΔTS is positive. Consequently, the recorded high ΔTS/ΔTP for events in the southwest Pacific and stations in North America may be misinterpreted as an anomalously high R for the Pacific LLVP

Distribution service : competition within and among retail formats

Distribution service provision is an important instrument for the creation of availability. The book addresses in five parts the role of distribution service in individual channel member decision making in a competitive retailing environment through theoretical and empirical modeling and analysis. The empirical applications all concern the Dutch domestic cut flower market. The book starts in part I with development of a new and integrative conceptualization for distribution service elaborating on views from logistics, economics, and psychology. The second part of the book addresses the theory underlying consumer evaluation of and choice from assortments. It provides a theoretical framework of consumption goals, situational, and contextual variables, including retailer distribution service provision, as determinants of consumer evaluation of and choice from assortments. Several hypotheses are tested in an empirical study. Extended multinomial logit modeling of the experimental choice data has been used as a tool for optimization of retail assortments. Part III investigates the role of retail distribution service provision in consumer post-purchase evaluation processes and extends existing research on consumer post-purchase evaluation. Part IV focuses on the role of distribution service in vertical and horizontal strategic interactions between channel members, particularly between manufacturers and retailers, and its consequences for the emergence of different channel structures and retail formats. A game-theoretic model has been developed for retail competition with respect to price and distribution service and its consequences for the emergence of differentiated retail formats. Finally, part V discusses research implications and future research challenges.</p

Consumentengedrag Duurzame Groente AKK-project 'Duurzame Groenteketens'

Ten behoeve van het stimuleren van de vraag naar duurzame groente en het formuleren van een gerichte communicatiestrategie is een consumentenonderzoek uitgevoerd. In totaal zijn 254 klanten van 5 filialen van supermarktketen Jumbo en 300 gasten van 4 vakantieparken van Center Parcs in Nederland persoonlijk geïnterviewd. Vastgesteld is welke variabelen van invloed zijn op de voorkeur voor duurzame groente, het al dan niet kopen van duurzame groente en de frequentie waarmee duurzame groente wordt gekocht. Onderzocht is welke invloed ketenpartijen kunnen uitoefenen op het gedrag van de consument, in het bijzonder door middel van communicati

Forest edge effects on moss growth are amplified by drought

Forest fragmentation increases the amount of edges in the landscape. Differences in wind, radiation, and vegetation structure create edge-to-interior gradients in forest microclimate, and these gradients are likely to be more pronounced during droughts and heatwaves. Although the effects of climate extremes on edge influences have potentially strong and long-lasting impacts on forest understory biodiversity, they are not well understood and are not often considered in management and landscape planning. Here we used a novel method of retrospectively quantifying growth to assess biologically relevant edge influences likely caused by microclimate using Hylocomium splendens, a moss with annual segments. We examined how spatio-temporal variation in drought across 3 years and 46 sites in central Sweden, affected the depth and magnitude of edge influences. We also investigated whether edge effects during drought were influenced by differences in forest structure. Edge effects were almost twice as strong in the drought year compared to the non-drought years, but we did not find clear evidence that they penetrated deeper into the forest in the drought year. Edge influences were also greater in areas that had fewer days with rain during the drought year. Higher levels of forest canopy cover and tree height buffered the magnitude of edge influence in times of drought. Our results demonstrate that edge effects are amplified by drought, suggesting that fragmentation effects are aggravated when droughts become more frequent and severe. Our results suggest that dense edges and buffer zones with high canopy cover can be important ways to mitigate negative drought impacts in forest edges