Exotic galilean symmetry and non-commutative mechanics

Some aspects of the "exotic" particle, associated with the two-parameter central extension of the planar Galilei group are reviewed. A fundamental property is that it has non-commuting position coordinates. Other and generalized non-commutative models are also discussed. Minimal as well as anomalous coupling to an external electromagnetic field is presented. Supersymmetric extension is also considered. Exotic Galilean symmetry is also found in Moyal field theory. Similar equations arise for a semiclassical Bloch electron, used to explain the anomalous/spin/optical Hall effects.Comment: Review paper. Published versio

Boundary-induced violation of the Dirac fermion parity and its signatures in local and global tunneling spectra of graphene

Extended defects in graphene, such as linear edges, break the translational invariance and can also have an impact on the symmetries specific to massless Dirac-like quasiparticles in this material. The paper examines the consequences of a broken Dirac fermion parity in the framework of the effective boundary conditions varying from the Berry-Mondragon mass confinement to a zigzag edge. The parity breaking reflects the structural sublattice asymmetry of zigzag-type edges and is closely related to the previously predicted time-reversal symmetric edge states. We calculate the local and global densities of the edge states and show that they carry a specific polarization, resembling, to some extent, that of spin-polarized materials. The lack of the parity leads to a nonanalytical particle-hole asymmetry in the edge-state properties. We use our findings to interpret recently observed tunneling spectra in zigzag-terminated graphene. We also propose a graphene-based tunneling device where the particle-hole asymmetric edge states result in a strongly nonlinear conductance-voltage characteristics, which could be used to manipulate the tunneling transport.Comment: 8 pages, 5 figures, to be published in Phys. Rev.

Design and Implementation of Distributed Resource Management for Time Sensitive Applications

In this paper, we address distributed convergence to fair allocations of CPU resources for time-sensitive applications. We propose a novel resource management framework where a centralized objective for fair allocations is decomposed into a pair of performance-driven recursive processes for updating: (a) the allocation of computing bandwidth to the applications (resource adaptation), executed by the resource manager, and (b) the service level of each application (service-level adaptation), executed by each application independently. We provide conditions under which the distributed recursive scheme exhibits convergence to solutions of the centralized objective (i.e., fair allocations). Contrary to prior work on centralized optimization schemes, the proposed framework exhibits adaptivity and robustness to changes both in the number and nature of applications, while it assumes minimum information available to both applications and the resource manager. We finally validate our framework with simulations using the TrueTime toolbox in MATLAB/Simulink

Berry phase correction to electron density in solids and "exotic" dynamics

Recent results on the semiclassical dynamics of an electron in a solid are explained using techniques developed for ``exotic'' Galilean dynamics. The system is indeed Hamiltonian and Liouville's theorem holds for the symplectic volume form. Suitably defined quantities satisfy hydrodynamic equations.Comment: Affiliation of the first Author expanded. One more reference added. To appear in Mod. Phys. Lett. B. 5 page

Role Of Point Of Care Ultrasound In The Diagnosis Of Retinal Detachment In The Emergency Department.

Ocular complaints represent up to 3% of all emergency department (ED) visits. These presentations can result in permanent vision loss if not promptly diagnosed and treated. Recently, point of care ultrasound (POCUS) has been investigated for the evaluation of ocular pathology in the ED. Multiple studies have investigated the role that ultrasound may play in the early diagnosis of these patients. Ocular ultrasound can be used to visualize the structures of the eye and evaluate for pathology such as retinal detachment, vitreous hemorrhage and vitreous detachment. This comprehensive review aims to present current evidence for the efficacy and reliability of ED ocular ultrasound use in the detection of retinal detachment and additional ocular pathologies

Informed consent in refractive surgery: in-person vs telemedicine approach.

Purpose:The aim of this study was to compare the quality of consent process in refractive surgery between patients who had a preoperative consent discussion with the surgeon using a telemedicine approach and those who had a face-to-face discussion. Methods:Patients treated between January and December 2017 (8,184 laser vision correction [LVC] and 3,754 refractive lens exchange [RLE] patients) that attended day 1 and 1-month postoperative visit were retrospectively reviewed. Preoperative consent preparation included a consultation with an optometrist, observation of an educational video, and written information. Patients then selected either a face-to-face appointment with their surgeon (in-clinic group) or a telemedicine appointment (remote group) for their consent discussion, according to their preference. Patient experience questionnaire and clinical data were included in a multivariate model to explore factors associated with consent quality. Results:Prior to surgery, 80.1% of LVC and 47.9% of RLE patients selected remote consent. Of all LVC patients, 97.5% of in-clinic and 98.3% of remote patients responded that they were adequately consented for surgery (P=0.04). Similar percentages in the RLE group were 97.6% for in-clinic and 97.9% for remote patients (P=0.47). In a multivariate model, the major predictor of patient's satisfaction with the consent process was postoperative satisfaction with visual acuity, responsible for 80.4% of variance explained by the model. Other significant contributors were postoperative visual phenomena and dry eyes, difficulty with night driving, close-up and distance vision, postoperative uncorrected distance visual acuity, change in corrected distance visual acuity, and satisfaction with the surgeon's approach. The type of consent (remote or in-clinic) had no impact on patient's perception of consent quality in the regression model. Conclusion:The majority of patients opted for telemedicine-assisted consent. Those who chose it were equally satisfied as those who had a face-to-face meeting with their surgeon. Dissatisfaction with surgical outcome was the major factor affecting patient's perception of consent quality, regardless of the method of their consent

DRM and modchips: Time for the Court of Justice to do the "right" thing

This paper looks at three key cases; UsedSoft (C-458/13), PC Box (C-355/12) and Grund (C-458/13), on the topic of the extent and nature of a copyright holders abilityto constrain future uses of their copyrighted works in the field of software and critically considers the interaction between copyright and competition law in these judgements.In UsedSoft, the Court of Justice of the European Union (hereafter CJEU) shook the common-law world by suggesting that under certain circumstances the licensing of a piece of software could constitute a sale, they achieved this by focusing on the balance of right between the user and the vendor and more importantly, on the “specific subject matter” of the right granted.In PC Box, a more economically cautious judgement, but one with intellectual consonance with UsedSoft, the CJEU looked at the issue of 'modchips' to permit homebrew and other non-approved games to be played on Nintendo consoles. They decided that the TPM (technological protection measures) embedded in the consoles were analogous to the other more traditional methods of encryption and DRM (digital rights management) employed in standard software. However, the judgement also highlighted that the use of a balancing test with regard to the appropriateness of the TPM devices in consoles was necessary. Furthermore, the Court judged that the national courts should carry out a 'real world' market test to see if the use of modchips truly adversely affected the interests of the copyright holder i.e. how of then they were used for infringing as opposed to non-infringing uses.Finally, we shall consider the key case that never was - Grund. This case was, and remains, something of an enigma as the preliminary reference questions were difficultto comprehend but nevertheless promised important clarifications in the law.However, we will consider it in this discussion largely because the reference was ultimately withdrawn because the parties were convinced that the issue was resolved by the judgement in PC Box. Thus it offers an insight into the future utility of theUsedSoft and PC Box judgements

Carotenoids - Effective Radical Scavengers for Healthy and Beautiful Skin

Free radicals are involved in various diseases and skin aging. To reduce and prevent this risk, our body produces antioxidants that can neutralize free radicals. However, some antioxidants need to be taken up with food, so a balanced and varied diet is essential for human health and beauty, along with sufficient exercise. Vegetables, especially curly kale, show very good antioxidative capacity due to the presence of carotenoids. As the recommended daily intake of vegetables is usually not consumed, dietary supplements are a good possibility to ingest carotenoids in a controlled and natural way. The positive effect of carotenoid-based dietary supplements on the skin has already been shown in several studies on healthy volunteers. Innovative non-invasive measuring methods have shown that oil extracts from vegetables significantly reduce not only free radicals in the skin but also the age-related breakdown of collagen and have a positive effect on skin parameters such as wrinkle volume. Thus, a balanced mixture of different natural carotenoids contributes to maintaining health and beauty