96,696 research outputs found

    Active repositioning of storage units in Robotic Mobile Fulfillment Systems

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    In our work we focus on Robotic Mobile Fulfillment Systems in e-commerce distribution centers. These systems were designed to increase pick rates by employing mobile robots bringing movable storage units (so-called pods) to pick and replenishment stations as needed, and back to the storage area afterwards. One advantage of this approach is that repositioning of inventory can be done continuously, even during pick and replenishment operations. This is primarily accomplished by bringing a pod to a storage location different than the one it was fetched from, a process we call passive pod repositioning. Additionally, this can be done by explicitly bringing a pod from one storage location to another, a process we call active pod repositioning. In this work we introduce first mechanisms for the latter technique and conduct a simulation-based experiment to give first insights of their effect

    A brief overview of current drug repurposing approaches for COVID-19 management

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    This brief overview is intended to shed light on the current drug repositioning (also called drug repurposing) in the therapeutics of the novel coronavirus disease which emerged in 2019 (COVID-19). In this sense, the repositioning drugs for new indications can offer a better risk-versus-reward trade-off when compared to other drug development strategies, given that it makes use of drugs whose safety profile are already understood. Nonetheless, this approach allows healthcare professionals to promptly tackle the disease by investigating readily available drugs against it

    Investigating human memory of self-position using a virtual 3-dimensional visual environment

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    Knowing one's location in space is crucial for navigation, especially in unknown environments. Recently, systems involved in self-localization for spatial navigation have been found in rodent brains, but the mechanisms for self-localization are not completely understood. Human behavioral experiments can enhance understanding of self-localization systems in human brains. In this study, human observers are placed in a visual virtual reality (VR) to perform a self-positioning task. The VR is created using a 120 Hz projector and a polarizing filter which separates left and right eye images when passed through 3D glasses. Disparity and size cues generate the perception of depth. Participants are placed in a virtual position on the ground for five seconds and then moved by changing their virtual environment around a stable object. Their task is to return to their initial position on the ground with button controls. Principal component analyses show that errors in self-repositioning are not along any particular axes and each participant has a unique pattern of repositioning. Trial durations do not affect accuracy of repositioning and lack of disparity cues increases the standard error of repositioning in all directions. Some participants have lower errors when initial self-positions appear to be on one or the other side of the stable object, suggesting a link between memory of self-position and a preferred point of reference. Future directions of this project are to explore between-subject differences and the effect of stimulus presentation at different frequencies on memory of self-position.Published versionSupporting documentatio

    STRATEGICALLY REPOSITIONING RUSSIA

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    Positioning is a very important marketing concept. Its importance was strongly emphasized and implemented in the case of companies, but is somehow neglected when it comes to states. A country acquires a position in the mind of a person very much like any other product does, which is very important especially when that person exerts an executive role. Nowadays Russia has a poor image or no image at all, both internationally and in Romania. In order to regain an important position in the Balkans region, Russia must set aside any political agenda and reposition itself as a business partner on equal terms. The first goal of this article is to clarify Russia's position in the minds of future Romanian executives. The second goal is to outline a recommended course of actions for Russia's repositioning.marketing, positioning, strategy, Russia, marketing research

    Rapid chromosome territory relocation by nuclear motor activity in response to serum removal in primary human fibroblasts

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    This article has been made available through the Brunel Open Access Publishing Fund.Background: Radial chromosome positioning in interphase nuclei is nonrandom and can alter according to developmental, differentiation, proliferation, or disease status. However, it is not yet clear when and how chromosome repositioning is elicited. Results: By investigating the positioning of all human chromosomes in primary fibroblasts that have left the proliferative cell cycle, we have demonstrated that in cells made quiescent by reversible growth arrest, chromosome positioning is altered considerably. We found that with the removal of serum from the culture medium, chromosome repositioning took less than 15 minutes, required energy and was inhibited by drugs affecting the polymerization of myosin and actin. We also observed that when cells became quiescent, the nuclear distribution of nuclear myosin 1Ăź was dramatically different from that in proliferating cells. If we suppressed the expression of nuclear myosin 1Ăź by using RNA-interference procedures, the movement of chromosomes after 15 minutes in low serum was inhibited. When high serum was restored to the serum-starved cultures, chromosome repositioning was evident only after 24 to 36 hours, and this coincided with a return to a proliferating distribution of nuclear myosin 1Ăź. Conclusions: These findings demonstrate that genome organization in interphase nuclei is altered considerably when cells leave the proliferative cell cycle and that repositioning of chromosomes relies on efficient functioning of an active nuclear motor complex that contains nuclear myosin 1Ăź.Brunel Open Access Publishing Fun

    Management of anterior chamber dislocation of a dexamethasone intravitreal implant: a case report

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    Background Ozurdex is a 700 mcg dexamethasone intravitreal implant, approved for the management of macular edema secondary to retinal vein occlusion, and other related pathoglogiesAnterior chamber dislocation of Ozurdex represents an uncommon complication of the intravitreal injection, which can be managed by repositioning the implant into the vitreous cavity. We describe the case of a successful repositioning of an Ozurdex implant by mobilization and subsequent balanced saline solution injection in the anterior chamber. Case presentation An 83-year-old white woman presented to our Emergency Unit complaining of pain and vision loss in herright eye lasting a week. Her anamnesis revealed a history of persistent cystoid macular edema after phacoemulsification with scleral-fixated posterior chamber intraocular lens implantation, recently treated with an intravitreal Ozurdex implant. She also took a long-distance flight 2 days after the injection. An anterior segment examination showed corneal edema and the rod implant adherent to corneal endothelium. To avoid corneal decompensation, we opted for a implant repositioning. Under topical anesthesia, a 30-gauge needle was introduced through a limbar incisionto mobilize the dislocated rod. Balanced saline solution was injected, with a successful repositioning of the implant into the vitreous cavity. Topical 5 % hypertonic saline solution and 0.2 % betamethasone associated with 0.5 % chloramphenicol drops were administered four times a day. To prevent redislocation of the Ozurdex implant, she was instructed to avoid prone position, any kind of physical effort, and not to undertake long-distance flights during the first postoperative week. One week after surgery, an anterior segment examination showed an improvement of corneal edema. Funduscopy showed that the Ozurdex implant was settled into the vitreous cavity. Conclusions Anterior chamber dislocation of Ozurdex from the vitreous cavity is rare. In our patient, in addition to the posterior capsule tearing, the long-distance flight could have contributed to implant dislocation. Repositioning of the implant is necessary to avoid endothelial decompensation. It can be carried out by using saline balanced solution with the same efficacy as other surgical procedures reported in the literature. A possible disadvantage of this procedure could be implant migration

    Polymer reptation and nucleosome repositioning

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    We consider how beads can diffuse along a chain that wraps them, without becoming displaced from the chain; our proposed mechanism is analogous to the reptation of "stored length" in more familiar situations of polymer dynamics. The problem arises in the case of globular aggregates of proteins (histones) that are wound by DNA in the chromosomes of plants and animals; these beads (nucleosomes) are multiply wrapped and yet are able to reposition themselves over long distances, while remaining bound by the DNA chain.Comment: 9 pages, including 2 figures, to be published in Phys. Rev. Let

    Nucleosome repositioning via loop formation

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    Active (catalysed) and passive (intrinsic) nucleosome repositioning is known to be a crucial event during the transcriptional activation of certain eucaryotic genes. Here we consider theoretically the intrinsic mechanism and study in detail the energetics and dynamics of DNA-loop-mediated nucleosome repositioning, as previously proposed by Schiessel et al. (H. Schiessel, J. Widom, R. F. Bruinsma, and W. M. Gelbart. 2001. {\it Phys. Rev. Lett.} 86:4414-4417). The surprising outcome of the present study is the inherent nonlocality of nucleosome motion within this model -- being a direct physical consequence of the loop mechanism. On long enough DNA templates the longer jumps dominate over the previously predicted local motion, a fact that contrasts simple diffusive mechanisms considered before. The possible experimental outcome resulting from the considered mechanism is predicted, discussed and compared to existing experimental findings

    Passion & Purpose: Raising the Fiscal Fitness Bar for Massachusetts Nonprofits

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    Presents data on and financial analyses of the state's nonprofit sector by organization type, budget, focus area, and location. Recommends better financial stewardship, restructuring, repositioning, and reinvestment to enhance nonprofits' sustainability
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