8,819 research outputs found

    Casimir force on a piston

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    We consider a massless scalar field obeying Dirichlet boundary conditions on the walls of a two-dimensional L x b rectangular box, divided by a movable partition (piston) into two compartments of dimensions a x b and (L-a) x b. We compute the Casimir force on the piston in the limit L -> infinity. Regardless of the value of a/b, the piston is attracted to the nearest end of the box. Asymptotic expressions for the Casimir force on the piston are derived for a << b and a >> b.Comment: 10 pages, 1 figure. Final version, accepted for publication in Phys. Rev.

    Wide-range optical spin orientation in Ge from near-infrared to visible light

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    Ge-based spin-photodiodes have been employed to investigate the spectral dependence of optical spin orientation in germanium, in the range 400-1550 nm. We found the expected maximum in the spin polarization of photocarriers for excitation at the direct gap in Γ (1550 nm) and a second sizable peak due to photogeneration in the L valleys (530 nm). Data suggest distinct spin depolarization mechanisms for excitation at Γ and L, with shorter spin relaxation times whether the X point is involved. These devices can be used as integrated photon-helicity detectors over a wide spectral range

    Migration cost optimization for service provider legacy network migration to software-defined IPv6 network

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    This is the peer reviewed version of the following article: Dawadi, BR, Rawat, DB, Joshi, SR, Manzoni, P, Keitsch, MM. Migration cost optimization for service provider legacy network migration to software-defined IPv6 network. Int J Network Mgmt. 2021; 31:e2145, which has been published in final form at https://doi.org/10.1002/nem.2145. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] This paper studies a problem for seamless migration of legacy networks of Internet service providers to a software-defined networking (SDN)-based architecture along with the transition to the full adoption of the Internet protocol version 6 (IPv6) connectivity. Migration of currently running legacy IPv4 networks into such new approaches requires either upgrades or replacement of existing networking devices and technologies that are actively operating. The joint migration to SDN and IPv6 network is considered to be vital in terms of migration cost optimization, skilled human resource management, and other critical factors. In this work, we first present the approaches of SDN and IPv6 migration in service providers' networks. Then, we present the common concerns of IPv6 and SDN migration with joint transition strategies so that the cost associated with joint migration is minimized to lower than that of the individual migration. For the incremental adoption of software-defined IPv6 (SoDIP6) network with optimum migration cost, a greedy algorithm is proposed based on optimal path and the customer priority. Simulation and empirical analysis show that a unified transition planning to SoDIP6 network results in lower migration cost.U.S. National Science Foundation (NSF), Grant/Award Number: CNS 1650831 and HRD 1828811; ERASMUS+ KA107; Nepal Academy of Science and Technology (NAST); Norwegian University of Science and Technology; University Grant Commission (UGC), Nepal, Grant/Award Number: FRG/74_75/Engg-1Dawadi, BR.; Rawat, DB.; Joshi, SR.; Manzoni, P.; Keitsch, MM. (2021). Migration cost optimization for service provider legacy network migration to software-defined IPv6 network. International Journal of Network Management. 31(4):1-24. https://doi.org/10.1002/nem.2145S124314APNIC.IPv6 capability measurement.https://stats.labs.apnic.net/ipv6. Accessed April 22 2020.Google Incl. IPv6 user access status.https://www.google.com/intl/en/ipv6/statistics.html. Accessed February 16 2020.Rawat, D. B., & Reddy, S. R. (2017). Software Defined Networking Architecture, Security and Energy Efficiency: A Survey. IEEE Communications Surveys & Tutorials, 19(1), 325-346. doi:10.1109/comst.2016.2618874Dai, B., Xu, G., Huang, B., Qin, P., & Xu, Y. (2017). Enabling network innovation in data center networks with software defined networking: A survey. Journal of Network and Computer Applications, 94, 33-49. doi:10.1016/j.jnca.2017.07.004Kobayashi, M., Seetharaman, S., Parulkar, G., Appenzeller, G., Little, J., van Reijendam, J., 
 McKeown, N. (2014). Maturing of OpenFlow and Software-defined Networking through deployments. Computer Networks, 61, 151-175. doi:10.1016/j.bjp.2013.10.011Gumaste, A., Sharma, V., Kakadia, D., Yates, J., Clauberg, A., & Voltolini, M. (2017). SDN Use Cases for Service Provider Networks: Part 2. IEEE Communications Magazine, 55(4), 62-63. doi:10.1109/mcom.2017.7901478Dawadi, B. R., Rawat, D. B., & Joshi, S. R. (2019). Software Defined IPv6 Network: A New Paradigm for Future Networking. Journal of the Institute of Engineering, 15(2), 1-13. doi:10.3126/jie.v15i2.27636Shah, J. L., Bhat, H. F., & Khan, A. I. (2019). Towards IPv6 Migration and Challenges. International Journal of Technology Diffusion, 10(2), 83-96. doi:10.4018/ijtd.2019040105Rojas, E., Doriguzzi-Corin, R., Tamurejo, S., Beato, A., Schwabe, A., Phemius, K., & Guerrero, C. (2018). Are We Ready to Drive Software-Defined Networks? A Comprehensive Survey on Management Tools and Techniques. ACM Computing Surveys, 51(2), 1-35. doi:10.1145/3165290Contreras, L. M., Doolan, P., LĂžnsethagen, H., & LĂłpez, D. R. (2015). Operational, organizational and business challenges for network operators in the context of SDN and NFV. Computer Networks, 92, 211-217. doi:10.1016/j.comnet.2015.07.016Amin, R., Reisslein, M., & Shah, N. (2018). Hybrid SDN Networks: A Survey of Existing Approaches. IEEE Communications Surveys & Tutorials, 20(4), 3259-3306. doi:10.1109/comst.2018.2837161Audi Marc Amjad A.The Advancement in Information and Communication Technologies (ICT) and Economic Development: A Panel Analysis. MPRA.https://mpra.ub.uni-muenchen.de/93476/. Published 2019. Accessed November 29 2019.Main, A., Zakaria, N. A., & Yusof, R. (2015). Organisation Readiness Factors Towards IPv6 Migration: Expert Review. Procedia - Social and Behavioral Sciences, 195, 1882-1889. doi:10.1016/j.sbspro.2015.06.427Dawadi, B. R., Rawat, D. B., Joshi, S. R., & Baral, D. S. (2019). Affordable Broadband with Software Defined IPv6 Network for Developing Rural Communities. Applied System Innovation, 3(1), 4. doi:10.3390/asi3010004Nikkhah, M. (2016). Maintaining the progress of IPv6 adoption. Computer Networks, 102, 50-69. doi:10.1016/j.comnet.2016.02.027Dell, P. (2018). On the dual-stacking transition to IPv6: A forlorn hope? Telecommunications Policy, 42(7), 575-581. doi:10.1016/j.telpol.2018.04.005GilliganRE NordmarkE GilliganRE et alBasic Transition Mechanisms for IPv6 Hosts and Routers.2000.Cui, Y., Dong, J., Wu, P., Wu, J., Metz, C., Lee, Y. L., & Durand, A. (2013). Tunnel-Based IPv6 Transition. 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IETF Internet Draft.2015.TownsleyW TroanO.IPv6 Rapid Deployment on IPv4 Infrastructures (6rd)‐‐Protocol Specification.2010.ChenM ChenG JiangS LeeY DespresR PennoR.IPv4 Residual Deployment via IPv6‐A Stateless Solution (4rd).2015.WuP CuiY XuM et alPET: Prefixing encapsulation and translation for IPv4‐IPv6 coexistence. In: 2010IEEE Global Telecommunications Conference GLOBECOM2010. 2010:1–5.LiX BaoC ChenM ZhangH WuJ.IVI translation design and deployment for the IPv4/IPv6 coexistence and transition.IETF RFC6219 Internet Eng Task Force Fremont CA.2011.Bagnulo, M., Garcia-Martinez, A., & Van Beijnum, I. (2012). The NAT64/DNS64 tool suite for IPv6 transition. 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IEEE Communications Surveys & Tutorials, 15(3), 1407-1424. doi:10.1109/surv.2012.110112.00200Hernandez-Valencia, E., Izzo, S., & Polonsky, B. (2015). How will NFV/SDN transform service provider opex? IEEE Network, 29(3), 60-67. doi:10.1109/mnet.2015.7113227BogineniK et alThe Open Networking Lab (ON.Lab). Introducing ONOS—a SDN network operating system for Service Providers.White Pap.2014;1:14.http://onosproject.org/wp-content/uploads/2014/11/Whitepaper-ONOS-final.pdfTR‐506 O ONF TR‐506.SDN Migration Considerations and Use Cases.2014.https://www.opennetworking.org/wp-content/uploads/2014/10/sb-sdn-migration-use-cases.pdfRisdiantoAC LingTC TsaiP YangC KimJ.Leveraging open‐source software for federated multisite SDN‐cloud playground. In: 2016 IEEE NetSoft Conference and Workshops (NetSoft). ;2016:423‐427.https://doi.org/10.1109/NETSOFT.2016.7502479GalizaH SchwarzM BezerraJ IbarraJ.Moving an ip network to sdn: a global use case deployment experience at amlight. In:Anais Do WPEIF2016Workshop de Pesquisa Experimental Da Internet Do Futuro: 15.LevinD CaniniM SchmidS SchaffertF Feldmann A.Panopticon: Reaping the Benefits of Incremental {SDN} Deployment in Enterprise Networks. In: 2014 {USENIX} Annual Technical Conference ({USENIX}{ATC} 14). ;2014:333–345.Vissicchio, S., Tilmans, O., Vanbever, L., & Rexford, J. (2015). Central Control Over Distributed Routing. ACM SIGCOMM Computer Communication Review, 45(4), 43-56. doi:10.1145/2829988.2787497Huang, X., Cheng, S., Cao, K., Cong, P., Wei, T., & Hu, S. (2019). A Survey of Deployment Solutions and Optimization Strategies for Hybrid SDN Networks. IEEE Communications Surveys & Tutorials, 21(2), 1483-1507. doi:10.1109/comst.2018.2871061Csikor, L., Szalay, M., Retvari, G., Pongracz, G., Pezaros, D. P., & Toka, L. (2020). Transition to SDN is HARMLESS: Hybrid Architecture for Migrating Legacy Ethernet Switches to SDN. IEEE/ACM Transactions on Networking, 28(1), 275-288. doi:10.1109/tnet.2019.2958762Dawadi, B. R., Rawat, D. B., Joshi, S. R., & Manzoni, P. (2020). Legacy Network Integration with SDN-IP Implementation towards a Multi-Domain SoDIP6 Network Environment. Electronics, 9(9), 1454. doi:10.3390/electronics9091454HongDK MaY BanerjeeS MaoZM.Incremental deployment of SDN in hybrid enterprise and ISP networks. In: Proceedings of the Symposium on SDN Research. 2016:1‐7.Karakus, M., & Durresi, A. (2018). Economic Viability of Software Defined Networking (SDN). Computer Networks, 135, 81-95. doi:10.1016/j.comnet.2018.02.015Rizvi, S. N., Raumer, D., Wohlfart, F., & Carle, G. (2015). Towards carrier grade SDNs. Computer Networks, 92, 218-226. doi:10.1016/j.comnet.2015.09.029Sezer, S., Scott-Hayward, S., Chouhan, P., Fraser, B., Lake, D., Finnegan, J., 
 Rao, N. (2013). Are we ready for SDN? Implementation challenges for software-defined networks. IEEE Communications Magazine, 51(7), 36-43. doi:10.1109/mcom.2013.6553676Raza, M. H., Sivakumar, S. C., Nafarieh, A., & Robertson, B. (2014). A Comparison of Software Defined Network (SDN) Implementation Strategies. Procedia Computer Science, 32, 1050-1055. doi:10.1016/j.procs.2014.05.532Goransson, P., & Black, C. (2014). SDN in the Data Center. Software Defined Networks, 145-167. doi:10.1016/b978-0-12-416675-2.00007-3AT & T.Introducing the “User Defined Network Cloud”.https://about.att.com/newsroom/introducing_the_user_defined_network_cloud.html. Published 2014. Accessed August 12 2018.CsikorL TokaL SzalayM PongrĂĄczG PezarosDP RĂ©tvĂĄriG.HARMLESS: Cost‐effective transitioning to SDN for small enterprises. In: 2018 IFIP Networking Conference (IFIP Networking) and Workshops. ; 2018:1–9.ON.LAB.Driving SDN Adoption in Service Provider Networks.2014.http://onosproject.org/wp-content/uploads/2014/11/Whitepaper-Service-Provider-SDN-final.pdfBabikerH NikolovaI ChittimaneniKKK.Deploying IPv6 in the Google Enterprise Network. Lessons learned. In:LISA'11 Proceedings of the 25th International Conference on Large Installation System Administration 2011:10.ParkHW HwangISLS LeeJR.Study on the sustainable migration to software defined network for nation‐wide R&E network.Proc—201610th Int Conf Innov Mob Internet Serv Ubiquitous Comput IMIS2016.2016:392‐396.https://doi.org/10.1109/IMIS.2016.117CariaM JukanA HoffmannM.A performance study of network migration to SDN‐enabled traffic engineering. In:2013 IEEE Global Communications Conference (GLOBECOM); 2013:1391‐1396.Sandhya, Sinha, Y., & Haribabu, K. (2017). A survey: Hybrid SDN. Journal of Network and Computer Applications, 100, 35-55. doi:10.1016/j.jnca.2017.10.003LENCSE, G., & KADOBAYASHI, Y. (2019). Comprehensive Survey of IPv6 Transition Technologies: A Subjective Classification for Security Analysis. IEICE Transactions on Communications, E102.B(10), 2021-2035. doi:10.1587/transcom.2018ebr0002NIST.Technical and Economic Assessment of Internet Protocol Verson 6 9IPv6.2006.https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=912231NIST.IPv6 Economic Impact Assessment. NY;2005.https://www.nist.gov/system/files/documents/director/planning/report05-2.pdfDasT CariaM JukanA HoffmannM.A Techno‐economic Analysis of Network Migration to Software‐Defined Networking.2013.http://arxiv.org/abs/1310.0216Das, T., Drogon, M., Jukan, A., & Hoffmann, M. (2014). Study of Network Migration to New Technologies Using Agent-Based Modeling Techniques. Journal of Network and Systems Management, 23(4), 920-949. doi:10.1007/s10922-014-9327-3Yuan, T., Huang, X., Ma, M., & Zhang, P. (2017). Migration to software-defined networks: The customers’ view. China Communications, 14(10), 1-11. doi:10.1109/cc.2017.8107628TĂŒrkS LiuY RadekeR LehnertR.Network migration optimization using genetic algorithms. In: Meeting of the European Network of Universities and Companies in Information and Communication Engineering. 2012:112–123.TĂŒrk, S. (2014). Network migration optimization using meta-heuristics. AEU - International Journal of Electronics and Communications, 68(7), 584-586. doi:10.1016/j.aeue.2014.04.005TĂŒrkS RadekeR LehnertR.Network migration using ant colony optimization. In:2010 9th Conference of Telecommunication Media and Internet; 2010:1–6.TurkS LiuH RadekeR LehnertR.Improving network migration optimization utilizing memetic algorithms. In: Global Information Infrastructure Symposium—GIIS 2013. 2013:1‐8.https://doi.org/10.1109/GIIS.2013.6684345ShayaniD Mas MachucaC JagerM GladischA.Cost analysis of the service migration problem between communication platforms. In: NOMS 2008–2008 IEEE Network Operations and Management Symposium. 2008:734‐737.https://doi.org/10.1109/NOMS.2008.4575201Shayani, D., Mas Machuca, C., & Jager, M. (2010). A techno-economic approach to telecommunications: the case of service migration. IEEE Transactions on Network and Service Management, 7(2), 96-106. doi:10.1109/tnsm.2010.06.i8p0297Naudts, B., Kind, M., Verbrugge, S., Colle, D., & Pickavet, M. (2015). How can a mobile service provider reduce costs with software-defined networking? International Journal of Network Management, 26(1), 56-72. doi:10.1002/nem.1919Dawadi, B. R., Rawat, D. B., & Joshi, S. R. (2019). Evolutionary Dynamics of Service Provider Legacy Network Migration to Software Defined IPv6 Network. Advances in Intelligent Systems and Computing, 245-257. doi:10.1007/978-3-030-19861-9_24BezrukVM ChebotarovaD V KaliuzhniyNM QiangG YuZ.Optimization and mathematical modeling of communication networks.Monogr—Open Electron Arch Kharkov Natl Univ Radio Electron.2019.http://openarchive.nure.ua/handle/document/10121Omantek. Open‐AudIT: Device Information Management System.https://www.open-audit.org/about.phpNet. Inventory Advisor.Network Inventory Software.https://www.network-inventory-advisor.com/. Accessed December 3 2019.OCS‐Inventory. OCSING: Open Inventory Next Generation.https://ocsinventory-ng.org/?lang=en. Accessed December 3 2019.Group MW. Migration Use Cases and Methods Migration Working Group Open Networking Foundation Use Cases and Migration Methods 2.www.opennetworking.orgSohn, S. Y., & Kim, Y. (2011). Economic Evaluation Model for International Standardization of Correlated Technologies. 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In: 2007 ITG Symposium on Photonic Networks. ; 2007:1–5.Poularakis, K., Iosifidis, G., Smaragdakis, G., & Tassiulas, L. (2019). Optimizing Gradual SDN Upgrades in ISP Networks. IEEE/ACM Transactions on Networking, 27(1), 288-301. doi:10.1109/tnet.2018.2890248GalĂĄn-JimĂ©nez, J. (2017). Legacy IP-upgraded SDN nodes tradeoff in energy-efficient hybrid IP/SDN networks. Computer Communications, 114, 106-123. doi:10.1016/j.comcom.2017.10.010Vizarreta, P., Trivedi, K., Helvik, B., Heegaard, P., Blenk, A., Kellerer, W., & Mas Machuca, C. (2018). Assessing the Maturity of SDN Controllers With Software Reliability Growth Models. IEEE Transactions on Network and Service Management, 15(3), 1090-1104. doi:10.1109/tnsm.2018.2848105Salsano, S., Ventre, P. L., Lombardo, F., Siracusano, G., Gerola, M., Salvadori, E., 
 Prete, L. (2016). Hybrid IP/SDN Networking: Open Implementation and Experiment Management Tools. IEEE Transactions on Network and Service Management, 13(1), 138-153. doi:10.1109/tnsm.2015.2507622DasT GurusamyM.Resilient Controller Placement in Hybrid SDN/Legacy Networks. In: 2018 IEEE Global Communications Conference (GLOBECOM). 2018:1–7.DasT GurusamyM.INCEPT: INcremental ControllEr PlacemenT in software defined networks. In: 2018 27th International Conference on Computer Communication and Networks (ICCCN). 2018:1–6

    Carrier-envelope phase effects on the strong-field photoemission of electrons from metallic nanostructures

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    Sharp metallic nanotapers irradiated with few-cycle laser pulses are emerging as a source of highly confined coherent electron wavepackets with attosecond duration and strong directivity. The possibility to steer, control or switch such electron wavepackets by light is expected to pave the way towards direct visualization of nanoplasmonic field dynamics and real-time probing of electron motion in solid state nanostructures. Such pulses can be generated by strong-field induced tunneling and acceleration of electrons in the near-field of sharp gold tapers within one half-cycle of the driving laser field. Here, we show the effect of the carrier-envelope phase of the laser field on the generation and motion of strong-field emitted electrons from such tips. This is a step forward towards controlling the coherent electron motion in and around metallic nanostructures on ultrashort length and time scales

    Vacuum local and global electromagnetic self-energies for a point-like and an extended field source

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    We consider the electric and magnetic energy densities (or equivalently field fluctuations) in the space around a point-like field source in its ground state, after having subtracted the spatially uniform zero-point energy terms, and discuss the problem of their singular behavior at the source's position. We show that the assumption of a point-like source leads, for a simple Hamiltonian model of the interaction of the source with the electromagnetic radiation field, to a divergence of the renormalized electric and magnetic energy density at the position of the source. We analyze in detail the mathematical structure of such singularity in terms of a delta function and its derivatives. We also show that an appropriate consideration of these singular terms solves an apparent inconsistency between the total field energy and the space integral of its density. Thus the finite field energy stored in these singular terms gives an important contribution to the self-energy of the source. We then consider the case of an extended source, smeared out over a finite volume and described by an appropriate form factor. We show that in this case all divergences in local quantities such as the electric and the magnetic energy density, as well as any inconsistency between global and space-integrated local self-energies, disappear.Comment: 8 pages. The final publication is available at link.springer.co

    Learning high-order interactions for polygenic risk prediction

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    Within the framework of precision medicine, the stratification of individual genetic susceptibility based on inherited DNA variation has paramount relevance. However, one of the most relevant pitfalls of traditional Polygenic Risk Scores (PRS) approaches is their inability to model complex high-order non-linear SNP-SNP interactions and their effect on the phenotype (e.g. epistasis). Indeed, they incur in a computational challenge as the number of possible interactions grows exponentially with the number of SNPs considered, affecting the statistical reliability of the model parameters as well. In this work, we address this issue by proposing a novel PRS approach, called High-order Interactions-aware Polygenic Risk Score (hiPRS), that incorporates high-order interactions in modeling polygenic risk. The latter combines an interaction search routine based on frequent itemsets mining and a novel interaction selection algorithm based on Mutual Information, to construct a simple and interpretable weighted model of user-specified dimensionality that can predict a given binary phenotype. Compared to traditional PRSs methods, hiPRS does not rely on GWAS summary statistics nor any external information. Moreover, hiPRS differs from Machine Learning-based approaches that can include complex interactions in that it provides a readable and interpretable model and it is able to control overfitting, even on small samples. In the present work we demonstrate through a comprehensive simulation study the superior performance of hiPRS w.r.t. state of the art methods, both in terms of scoring performance and interpretability of the resulting model. We also test hiPRS against small sample size, class imbalance and the presence of noise, showcasing its robustness to extreme experimental settings. Finally, we apply hiPRS to a case study on real data from DACHS cohort, defining an interaction-aware scoring model to predict mortality of stage II-III Colon-Rectal Cancer patients treated with oxaliplatin

    Chronic migraine classification: current knowledge and future perspectives

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    In the field of so-called chronic daily headache, it is not easy for migraine that worsens progressively until it becomes daily or almost daily to find a precise and universally recognized place within the current international headache classification systems. In line with the 2006 revision of the second edition of the International Classification of Headache Disorders (ICHD-2R), the current prevailing opinion is that this headache type should be named chronic migraine (CM) and be characterized by the presence of at least 15 days of headache per month for at least 3 consecutive months, with headache having the same clinical features of migraine without aura for at least 8 of those 15 days. Based on much evidence, though, a CM with the above characteristics appears to be a heterogeneous entity and the obvious risk is that its definition may be extended to include a variety of different clinical entities. A proposal is advanced to consider CM a subtype of migraine without aura that is characterized by a high frequency of attacks (10–20 days of headache per month for at least 3 months) and is distinct from transformed migraine (TM), which in turn should be included in the classification as a complication of migraine. Therefore, CM should be removed from its current coding position in the ICHD-2 and be replaced by TM, which has more restrictive diagnostic criteria (at least 20 days of headache per month for at least 1 year, with no more than 5 consecutive days free of symptoms; same clinical features of migraine without aura for at least 10 of those 20 days)

    mTOR independent alteration in ULK1 Ser758 phosphorylation following chronic LRRK2 kinase inhibition

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    Unc-51 Like Kinase 1 (ULK1) is a critical regulator of the biogenesis of autophagosomes, the central component of the catabolic macroautophagy pathway. Regulation of ULK1 activity is dependent upon several phosphorylation events acting to repress or activate the enzymatic function of this protein. Phosphorylation of Ser758 ULK1 has been linked to repression of autophagosome biogenesis and was thought to be exclusively dependent upon mTOR complex 1 kinase activity. In this study, a novel regulation of Ser758 ULK1 phosphorylation is reported following prolonged inhibition of the Parkinson's disease linked protein Leucine Rich Repeat Kinase 2 (LRRK2). Here, modulation of Ser758 ULK1 phosphorylation following LRRK2 inhibition is decoupled from the repression of autophagosome biogenesis and independent of mTOR complex 1 activity

    The perseverance of Pacioli's goods inventory accounting system

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    This paper details sources of the 'undoubtedly strange' (Yamey, 1994a, p.119) system of goods inventory records described in Pacioli’s 1494 bookkeeping treatise and traces the longevity and widespread use of this early perpetual inventory recording (EPIR) system in English language texts. By doing so and contrasting this system with the bookkeeping treatment of modern texts, it is shown that the EPIR system persisted as the dominant form of goods inventory accounting for between 400 and 500 years and that the reasons for its demise are worthy of further consideration and research
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