461 research outputs found

    When Offline Stores Reduce Online Returns

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    Among the dark sides of contemporary multi-channel retailing are the vast amounts of product returns, especially in the online channel. High product returns not only put pressure on the retailers' profitability, but also come at high societal and environmental costs. A central question then is whether multi-channel retailers can use their offline stores to help reduce product returns in the online channel without harming online sales. In an empirical study, we address this issue using data from a large Dutch shoe retailer. We develop a novel spatial model to estimate the influence of proximate retail stores on customers' online shopping behavior, while controlling for spatial and customer heterogeneity. Results demonstrate that an increased offline channel presence indeed reduces online returns, depending on the product's risk profile, without significantly lowering online sales. Offline stores can thus be an effective and appealing way for retailers to mitigate the negative impact of online shopping related to product returns

    Hybrid robotic and electrical stimulation assistance can enhance performance and reduce mental demand

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    Combining functional electrical stimulation (FES) and robotics may enhance recovery after stroke, by providing neural feedback with the former while improv- ing quality of motion and minimizing muscular fatigue with the latter. Here, we explored whether and how FES, robot assistance and their combination, affect users’ per- formance, effort, fatigue and user experience. 15 healthy participants performed a wrist flexion/extension tracking task with FES and/or robotic assistance. Tracking per- formance improved during the hybrid FES-robot and the robot-only assistance conditions in comparison to no assistance, but no improvement is observed when only FES is used. Fatigue, muscular and voluntary effort are estimated from electromyographic recording. Total muscle contraction and volitional activity are lowest with robotic assistance, whereas fatigue level do not change between the conditions. The NASA-Task Load Index answers indi- cate that participants found the task less mentally demand- ing during the hybrid and robot conditions than the FES condition. The addition of robotic assistance to FES train- ing might thus facilitate an increased user engagement compared to robot training and allow longer motor training session than with FES assistance

    Physically interacting humans regulate muscle coactivation to improve visuo-haptic perception.

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    When moving a piano or dancing tango with a partner, how should I control my arm muscles to sense their movements and follow or guide them smoothly? Here we observe how physically connected pairs tracking a moving target with the arm modify muscle coactivation with their visual acuity and the partner's performance. They coactivate muscles to stiffen the arm when the partner's performance is worse and relax with blurry visual feedback. Computational modeling shows that this adaptive sensing property cannot be explained by the minimization of movement error hypothesis that has previously explained adaptation in dynamic environments. Instead, individuals skillfully control the stiffness to guide the arm toward the planned motion while minimizing effort and extracting useful information from the partner's movement. The central nervous system regulates muscle activation to guide motion with accurate task information from vision and haptics while minimizing the metabolic cost. As a consequence, the partner with the most accurate target information leads the movement.NEW & NOTEWORTHY Our results reveal that interacting humans inconspicuously modulate muscle activation to extract accurate information about the common target while considering their own and the partner's sensorimotor noise. A novel computational model was developed to decipher the underlying mechanism: muscle coactivation is adapted to combine haptic information from the interaction with the partner and own visual information in a stochastically optimal manner. This improves the prediction of the target position with minimal metabolic cost in each partner, resulting in the lead of the partner with the most accurate visual information

    Sea ice decline drives biogeographical shifts of key Calanus species in the central Arctic Ocean

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    In recent decades, the central Arctic Ocean has been experiencing dramatic decline in sea ice coverage, thickness and extent, which is expected to have a tremendous impact on all levels of Arctic marine life. Here, we analyze the regional and temporal changes in pan-Arctic distribution and population structure of the key zooplankton species Calanus glacialis and C. hyperboreus in relation to recent changes in ice conditions, based on historical (1993–1998) and recent (2007–2016) zooplankton collections and satellite-based sea ice observations. We found strong correlations between Calanus abundance/population structure and a number of sea ice parameters. These relationships were particularly strong for C. glacialis, with higher numbers being observed at locations with a lower ice concentration, a shorter distance to the ice edge, and more days of open water. Interestingly, early stages of C. hyperboreus followed the same trends, suggesting that these two species substantially overlap in their core distribution area in the Arctic Ocean. Calanus glacialis and C. hyperboreus have been historically classified as shelf versus basin species, yet we conclude that both species can inhabit a wide range of bottom depths and their distribution in the Arctic Ocean is largely shaped by sea ice dynamics. Our data suggest that the core distribution patterns of these key zooplankton are shifting northwards with retreating sea ice and changing climate conditions.publishedVersio

    Climate fluctuations and the spring invasion of the North Sea by Calanus finmarchicus

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    The population of Calanus finmarchicus in the North Sea is replenished each spring by invasion from an overwintering stock located beyond the shelf edge. A combincation of field observations, statistical analysis of Continuous Plankton Recorder (CPR) data, and particle tracking model simulations, was used to investigate the processes involved in the cross-shelf invasion. The results showed that the main source of overwintering animals entering the North Sea in the spring is at depths of greater than 600m in the Faroe Shetland Channel, where concentrations of up to 620m -3 are found in association with the overflow of Norwegian Sea Deep Water (NSDW) across the Iceland Scotland Ridge. The input of this water mass to the Faroe Shetland Channel, and hence the supply of overwintering C. finmarchicus, has declined since the late 1960s due to changes in convective processes in the Greenland Sea. Beginning in February, animals start to emerge from the overwintering state and migrate to the surface waters, where their transport into the North Sea is mainly determined by the incidence of north-westerly winds that have declined since the 1960s. Together, these two factors explain a high proportion of the 30-year trends in spring abundance in the North Sea as measured by the CPR survey. Both the regional winds and the NSDW overflow are connected to the North Atlantic Oscillation Index (NAO), which is an atmospheric climate index, but with different time scales of response. Thus, interannual fluctuations in the NAO can cause immediate changes in the incidence of north-westerly winds without leading to corresponding changes in C. finmarchicus abundance in the North Sea, because the NSDW overflow responds over longer (decadal) time scales

    Treatment of retracted, postsurgical scars and reduction of locoregional edema using a combined three-dimensional approach of liposuction lipofilling, dissecting cannulas, and suspension sutures

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    Background : Post-surgical abdominal and inguinal scars are a frequent challenge in plastic surgery. There are limited non-invasive alternatives to address depressed and retracted scars. The associated retraction and fibrosis might cause lymphatic dysfunction with subsequent regional edema. The authors describe a combined surgical approach of liposuction, the use of dissecting cannulas, lipofilling, and Scarpa’s fascia suspension sutures in a prospective case series. Methods: The proposed procedure was performed in 22 consecutive patients between November 2012 and May 2015. Complications were assessed according to the Clavien-Dindo scale. Postoperative psychosocial, edema reduction, and patient satisfaction outcomes were gathered and analyzed based on blinded questionaries (Rosenberg Self-Esteem scale and a Cosmetic Procedures Screening Questionnaire (COPS)). Results: At 6 months, no major complications and 27.2% minor complications (Clavien-Dindo 1) were recorded. Four patients had superficial infections that settled with oral antibiotics and two patients developed a seroma. A significant improvement in self-esteem, aesthetic satisfaction, and social competence was found postoperatively in all patients. The novel technique reduced regional edema and scar-related self-consciousness. Patient satisfaction was rated very high, and all patients would recommend this surgery for abdominal or inguinal retracted scars. Conclusions: This study shows that the proposed technique is a safe minimally invasive alternative for the treatment of abdominal and inguinal retracted scars. The relatively high rate of minor complications is mainly due to the strict definition of the scale used. The results showed an improvement of local edema and high patient satisfaction. Level of evidence: Level IV, therapeuti

    Challenges at the marketing–operations interface in omni-channel retail environments

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    To compete in today’s omni-channel business context, it is essential for firms to co-ordinate their activities across channels and across different stages of the customer journey and the product flow. This requires firms to adopt an integrative approach, addressing each omni-channel design decision from a dual demand-side (marketing) and supply-side (operations) perspective. However, both in practice and in academic research, such an integrative approach is still in an immature stage. In this article, a framework is developed with the following key decision areas: (i) assortment & inventory, (ii) distribution & delivery and (iii) returns. These affect both the customer journey and the product flow. As a consequence of the resulting interdependencies between the firm’s functions, addressing the issues that arise in the three decision areas requires an integrated marketing and operations perspective. For each of the areas, the key decisions that affect or involve both the customer journey and product flow are identified first. Next, for each decision, the marketing and operational goals and the tensions that arise when these goals are not perfectly aligned are described. The opportunities for relieving these tensions are also discussed and possible directions for future research aimed at addressing these tensions and opportunities are presented.info:eu-repo/semantics/publishedVersio

    Piccole capitali creative

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    Nel secolo urbano che abbiamo di fronte, la citt\ue0 sar\ue0 lo scenario della competizione delle energie, delle risorse umane, delle intelligenze collettive e della creativit\ue0 per la costruzione di un\u2019evoluzione pi\uf9 compatibile con le identit\ue0 e le vocazioni e pi\uf9 sostenibile rispetto alle risorse ed alle sensibilit\ue0 del territorio. I segnali delle sue forme, delle sue relazioni e delle sue identit\ue0 sono gi\ue0 evidenti in alcune citt\ue0 del presente ed ad essi sono dedicate numerose ricerche urbanistiche, sociologiche ed economiche. Ma i segnali sono evidenti e trasmettono ispirazioni e stimoli anche a chi osserva la citt\ue0 per mestiere di progettista, di pianificatore, di stratega dello sviluppo. Il XXI secolo sar\ue0 l\u2019era indiscussa delle citt\ue0 e su di esse si misurer\ue0 lo sviluppo delle nazioni. Per la prima volta, pi\uf9 della met\ue0 della popolazione mondiale vivr\ue0 nelle citt\ue0, in Europa oggi la cifra \ue8 gi\ue0 di oltre il 75%, e nei paesi in via di sviluppo raggiunger\ue0 velocemente il 50%. Il mondo si svilupper\ue0 sia attorno a grandi megalopoli da decine di milioni di abitanti, ma anche attorno a citt\ue0 metropolitane, a conurbazioni diffuse e ad armature di micropoli: all\u2019armatura urbana delle citt\ue0 globali si annoder\ue0, soprattutto in Europa, l\u2019armatura delle citt\ue0 di secondo livello, produttrici di visioni alternative rispetto all\u2019esplosione delle megalopoli. L\u2019armatura urbana europea di secondo livello \u2013 le piccole capitali, sempre pi\uf9 citt\ue0-porta \u2013 si delinea come annodata attorno a \u201ccitt\ue0 della cultura\u201d, nel senso di citt\ue0 non solo detentrici di risorse culturali profonde lasciate dal palinsesto della storia, ma anche produttrici di nuova cultura: le culture-based competition cities saranno, infatti, quelle citt\ue0 in grado di competere nel panorama internazionale attraverso la valorizzazione e la promozione della propria identit\ue0 culturale, sia consolidata che in evoluzione

    Schur complement inequalities for covariance matrices and monogamy of quantum correlations

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    We derive fundamental constraints for the Schur complement of positive matrices, which provide an operator strengthening to recently established information inequalities for quantum covariance matrices, including strong subadditivity. This allows us to prove general results on the monogamy of entanglement and steering quantifiers in continuous variable systems with an arbitrary number of modes per party. A powerful hierarchical relation for correlation measures based on the log-determinant of covariance matrices is further established for all Gaussian states, which has no counterpart among quantities based on the conventional von Neumann entropy
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