929 research outputs found

    Oriented polaritons in strongly-coupled asymmetric double quantum well microcavities

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    Replacing independent single quantum wells inside a strongly-coupled semiconductor microcavity with double quantum wells produces a special type of polariton. Using asymmetric double quantum wells in devices processed into mesas allows the alignment of the electron levels to be voltage-tuned. At the resonant electronic tunnelling condition, we demonstrate that `oriented polaritons' are formed, which possess greatly enhanced dipole moments. Since the polariton-polariton scattering rate depends on this dipole moment, such devices could reach polariton lasing, condensation and optical nonlinearities at much lower threshold powers.Comment: 3 figure

    Domain Wall Junctions are 1/4-BPS States

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    We study N=1 SUSY theories in four dimensions with multiple discrete vacua, which admit solitonic solutions describing segments of domain walls meeting at one-dimensional junctions. We show that there exist solutions preserving one quarter of the underlying supersymmetry -- a single Hermitian supercharge. We derive a BPS bound for the masses of these solutions and construct a solution explicitly in a special case. The relevance to the confining phase of N=1 SUSY Yang-Mills and the M-theory/SYM relationship is discussed.Comment: 18 pages, 4 figures, uses RevTeX. Brief comments concerning lattices of junctions added. Version to appear in Phys. Rev.

    3D body scanning in the apparel industry: Do we really know where we are heading?

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    This paper through - the Diffusion of Innovation Model - shows that while 3D Body Scanning brings some refining and improvements of existing methods, it does not introduce new concepts that depart from traditional retail practices. 3D Body Scanning is - potentially - a powerful way of approaching size and fit in apparel and one that presents novel opportunities. Yet, despite the advantages that this technology offers, and the many initiatives that have taken place, 3D Body Scanning has not reached its full potential and has failed to produce the expected results held by many stakeholders. Stakeholders must increase collaboration to realise 3D Body Scanningā€™s relative advantage. Much of the potential has, however, been promoted by distinct organisations that are biases about how the diverse processes and structures will work together, whilst focussing on profit from their own incremental IP. In this paper we elicit 3D Body Scanningā€™s fundamental concepts, and its central goal to provide ā€˜glueā€™ needed to create an innovation. We offer further implications for researchers and policymakers about expecting and managing trends in technology. <br

    Online virtual fit is not yet fit for purpose: An analysis of fashion e-commerce interfaces

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    To unify the methodology of Virtual Fit platforms and allowing cross platform integration of 3D Body Scanning, the current Virtual Fit platforms need to be assessed in terms of their size recommendation approach and user interaction. Digital data, interactivity, and internet technology are changing the ways we interact in online shopping, with the Virtual Fit platforms having great potential to increase retail engagement and market share. This will support online purchasing activities while minimising the perceived risk in garment returns due to the poor sizing fit information. Current research has focused on the analysis of computer modelling techniques, avatars, cloth, fabric draping simulations, and customer behaviour / aesthetic impact in the online domain. From a technical perspective, these investigations offer an interesting insight, although do not address issues of implementation or customer attitude. Therefore, to judge the current and potential impact of such technologies, it is important to understand 1) how they are being enacted online, 2) the Interaction Design elements of the user journey, 3) the application (or lack thereof) of mathematical models, and 4) how such interfaces are embedded within websites. Once these four key questions have been answered a greater understanding of how 3D Body Scanning and Technologies integrated into eCommerce and Virtual Fit platforms in the consumer market may be reached. Through analysis of nine leading Virtual Fit platforms, the persona of a single female dress form was used to work through the customer journey. Through this, screen shot data captured along each stage in relation to the four research questions listed above. Following this, the study utilised content analysis structure with NVivo as a qualitative thematic analysis tool. This study found that despite a large number of platforms using virtual fit technology, only a handful companies exist that provide such technology and interfaces; often based upon subjective ā€˜previous purchasesā€™ rather than scientific prediction. This issue is made more complicated in how subjective measures such as personal perception of oneā€™s body is required (e.g. what size are you), besides body shape; a concept shown to be ā€˜brokenā€™ and not fit-for-purpose. In addition, many of the technologies use limited and often misinterpreted body measurements, the impact of which is explored in greater detail within the paper. This study contributes to the understanding of the information required from users by virtual fit platforms, and the understanding of the output as presented by virtual fit platforms. The research goal is to contribute to knowledge as a potential guideline for any future projects in virtual fit and to help direct body scanning developments to better support these platforms

    Mehanizam toksičnosti i detoksikacije organofosfornih spojeva s naglaskom na istraživanja u Hrvatskoj

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    This review comprises studies on the mechanisms of toxicity and detoxication of organophosphorus (OP) compounds done in Croatia in different research areas. One area is the synthesis of antidotes against OP poisoning and their in vivo testing in experimental animals. In vitro studies included in this review focus on the mechanisms of reversible inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), protection of cholinesterases from inhibition by OPs, and reactivation of phosphylated cholinesterases. The third area comprises distribution profiles of BChE and paraoxonase (PON) phenotypes in selected population groups and the detection of OPs and metabolites in humans. Finally, methods are described for the detection of OP compounds in human blood and other media by means of cholinesterase inhibitionPrikazana su istraživanja vođena u Hrvatskoj na različitim područjima mehanizma toksičnosti i detoksikacije organofosfornih (OP) spojeva. Jedno je područje sinteza antidota protiv otrovanja OP spojevima i testiranje in vivo antidota na eksperimentalnim životinjama. Istraživanja in vitro odnose se na mehanizam reverzibilne inhibicije acetilkolinesteraze (AChE) i buturilkolinesteraze (BChE), zaÅ”titu kolinesteraza od inhibicije OP spojevima te reaktivaciju fosfiliranih kolinesteraza. Treće je područje distribucija fenotipova BChE i paraoksonaze (PON) u odabranim populacijama te detekcija OP spojeva i njihovih metabolita u ljudima. Na kraju su opisane metode detekcije OP spojeva u ljudskoj krvi i drugim medijima koje se osnivaju na inhibiciji kolinesteraza

    Taxes, Trading or Both?: An Experimental Investigation of Abatement Investment under Alternative Emissions Regulation

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    Emissions taxes and emissions permit trading schemes are designed to reduce greenhouse gas (GHG) emissions by providing incentives for large emitters to invest in less emissions-intensive production technologies. Whereas taxes place a fixed price on emissions, tradable permit schemes include a secondary permit market, from which allowance prices emerge after the regulation enters into force. Under a newly imposed regulation, the delay in price information contributes to uncertainty about the future cost of compliance that liable emitters will face, thereby challenging liable entitiesā€™ ability to make optimal abatement investment decisions. Using laboratory experiments, this thesis examines the effects of a policy regime that is similar to the one implemented in Australia in 2012. The regime includes a staged transition over time from a regulation-free environment, to an emissions tax and then to emissions trading. The thesis examines the effects of such a staged transition on investment decisions, the level of emissions, permit prices and trading behavior, comparing it to standard policy regimes of only an emissions tax and only emissions permit trading. The findings suggest that a regime based on a staged transition from a tax to permit trading results in lower compliance costs and higher overall allocative efficiency compared to a regime based solely on emissions trading in a market of heterogeneous producing firms

    Individual consistency in migration strategies of a tropical seabird, the Round Island petrel

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    Background: In migratory species, the extent of within- and between-individual variation in migratory strategies can influence potential rates and directions of responses to environmental changes. Quantifying this variation requires tracking of many individuals on repeated migratory journeys. At temperate and higher latitudes, low levels of within-individual variation in migratory behaviours are common and may reflect repeated use of predictable resources in these seasonally-structured environments. However, variation in migratory behaviours in the tropics, where seasonal predictability of food resources can be weaker, remains largely unknown. Methods: Round Island petrels (Pterodroma sp.) are tropical, pelagic seabirds that breed all year round and perform long-distance migrations. Using multi-year geolocator tracking data from 62 individuals between 2009 and 2018, we quantify levels of within- and between-individual variation in non-breeding distributions and timings. Results: We found striking levels of between-individual variation in at-sea movements and timings, with non-breeding migrations to different areas occurring across much of the Indian Ocean and throughout the whole year. Despite this, repeat-tracking of individual petrels revealed remarkably high levels of spatial and temporal consistency in within-individual migratory behaviour, particularly for petrels that departed at similar times in different years and for those departing in the austral summer. However, while the same areas were used by individuals in different years, they were not necessarily used at the same times during the non-breeding period. Conclusions: Even in tropical systems with huge ranges of migratory routes and timings, our results suggest benefits of consistency in individual migratory behaviours. Identifying the factors that drive and maintain between-individual variation in migratory behaviour, and the consequences for breeding success and survival, will be key to understanding the consequences of environmental change across migratory ranges

    A replication study confirms the association of TNFSF4 (OX40L) polymorphisms with systemic sclerosis in a large European cohort

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    &lt;p&gt;&lt;b&gt;Objectives&lt;/b&gt; The aim of this study was to confirm the influence of TNFSF4 polymorphisms on systemic sclerosis (SSc) susceptibility and phenotypic features.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods&lt;/b&gt; A total of 8 European populations of Caucasian ancestry were included, comprising 3014 patients with SSc and 3125 healthy controls. Four genetic variants of TNFSF4 gene promoter (rs1234314, rs844644, rs844648 and rs12039904) were selected as genetic markers.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results&lt;/b&gt; A pooled analysis revealed the association of rs1234314 and rs12039904 polymorphisms with SSc (OR 1.15, 95% CI 1.02 to 1.31; OR 1.18, 95% CI 1.08 to 1.29, respectively). Significant association of the four tested variants with patients with limited cutaneous SSc (lcSSc) was revealed (rs1234314 OR 1.22, 95% CI 1.07 to 1.38; rs844644 OR 0.91, 95% CI 0.83 to 0.99; rs844648 OR 1.10, 95% CI 1.01 to 1.20 and rs12039904 OR 1.20, 95% CI 1.09 to 1.33). Association of rs1234314, rs844648 and rs12039904 minor alleles with patients positive for anti-centromere antibodies (ACA) remained significant (OR 1.23, 95% CI 1.10 to 1.37; OR 1.12, 95% CI 1.01 to 1.25; OR 1.22, 95% CI 1.07 to 1.38, respectively). Haplotype analysis confirmed a protective haplotype associated with SSc, lcSSc and ACA positive subgroups (OR 0.88, 95% CI 0.82 to 0.96; OR 0.88, 95% CI 0.80 to 0.96; OR 0.86, 95% CI 0.77 to 0.97, respectively) and revealed a new risk haplotype associated with the same groups of patients (OR 1.14, 95% CI 1.03 to 1.26; OR 1.20, 95% CI 1.08 to 1.35; OR 1.23, 95% CI 1.07 to 1.42, respectively).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions&lt;/b&gt; The data confirm the influence of TNFSF4 polymorphisms in SSc genetic susceptibility, especially in subsets of patients positive for lcSSc and ACA.&lt;/p&gt

    Neuroaxial anesthesia in a patient with progressive systemic sclerosis : case presentation and review of the literature on systemic sclerosis

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    BACKGROUND: Systemic sclerosis (SSc), a progressive disease characterized by excessive accumulation of connective tissue components. Although most patients have long survival, some of them progress rapidly to death. Pulmonary system involvement and pulmonary hypertension are the most frequent cause of death. When the patient with SSc is to be operated, the anesthetic procedure could be a serious problem. In this article, we report a combined spinal ā€“ epidural technique in a patient with progressive SSc and the anesthetic considerations that could be recommended for these patients. CASE PRESENTATION: A 68-year-old woman who had a history of progressive systemic sclerosis, pulmonary fibrosis, kyphoscoliosis and decreased oral apertura underwent total hip arthroplasty. This operation was performed successfully under combined spinal epidural anesthesia. CONCLUSION: Systemic sclerosis is a complex disease that involves multiple organ systems. Every aspects of anesthetic care may be altered or hindered by the pathogenesis of disease. Although the choice of regional or general anesthesia is unclear, to choose combined spinal epidural anesthesia may be useful

    The Omega Deformation From String and M-Theory

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    We present a string theory construction of Omega-deformed four-dimensional gauge theories with generic values of \epsilon_1 and \epsilon_2. Our solution gives an explicit description of the geometry in the core of Nekrasov and Witten's realization of the instanton partition function, far from the asymptotic region of their background. This construction lifts naturally to M-theory and corresponds to an M5-brane wrapped on a Riemann surface with a selfdual flux. Via a 9-11 flip, we finally reinterpret the Omega deformation in terms of non-commutative geometry. Our solution generates all modified couplings of the \Omega-deformed gauge theory, and also yields a geometric origin for the quantum spectral curve of the associated quantum integrable system.Comment: LaTeX, 35 pages, 1 figure. Appendix on couplings of hypermultiplets in N=4 SYM adde
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