909 research outputs found

    Theoretical And Numerical Evidence For The Potential Realization Of The Peregrine Soliton In Repulsive Two-Component Bose-Einstein Condensates

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    The Present Work Is Motivated By The Recent Experimental Realization Of The Townes Soliton In An Effective Two-Component Bose-Einstein Condensate By B. Bakkali-Hassan Et Al. [Phys. Rev. Lett. 127, 023603 (2021)PRLTAO0031-900710.1103/PhysRevLett.127.023603]. Here, We Use A Similar Multicomponent Platform To Exemplify Theoretically And Numerically, Within The Mean-Field Gross-Pitaevskii Framework, The Potential Toward The Experimental Realization Of A Different Fundamental Wave Structure, Namely The Peregrine Soliton. Leveraging The Effective Attractive Interaction Produced Within The Mixture\u27s Minority Species In The Immiscible Regime, We Illustrate How Initialization Of The Condensate With A Suitable Power-Law Decaying Spatial Density Pattern Yields The Robust Emergence Of The Peregrine Wave In The Absence And In The Presence Of A Parabolic Trap. We Then Showcase The Spontaneous Emergence Of The Peregrine Soliton Via A Suitably Crafted Wide Gaussian Initialization, Again Both In The Homogeneous Case And In The Trap Scenario. It Is Also Found That Narrower Wave Packets May Result In Periodic Revivals Of The Peregrine Soliton, While Broader Ones Give Rise To A Cascade Of Peregrine Solitons Arranged In A So-Called Christmas-Tree Structure. Strikingly, The Persistence Of These Rogue-Wave Structures Is Demonstrated In Certain Temperature Regimes As Well As In The Presence Of Transversal Excitations Through Three-Dimensional Computations In A Quasi-One-Dimensional Regime. This Proof-Of-Principle Illustration Is Expected To Represent A Practically Feasible Way To Generate And Observe This Rogue Wave In Realistic Current Ultracold Atom Experimental Settings

    Compactification in the Lightlike Limit

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    We study field theories in the limit that a compactified dimension becomes lightlike. In almost all cases the amplitudes at each order of perturbation theory diverge in the limit, due to strong interactions among the longitudinal zero modes. The lightlike limit generally exists nonperturbatively, but is more complicated than might have been assumed. Some implications for the matrix theory conjecture are discussed.Comment: 13 pages, 3 epsf figures. References and brief comments added. Nonexistent divergent graph in 0+- model delete

    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.

    Deferasirox drives ROS-mediated differentiation and induces interferon-stimulated gene expression in human healthy haematopoietic stem/progenitor cells and in leukemia cells

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    Background: Administration of the iron chelator deferasirox (DFX) in transfusion-dependent patients occasionally results in haematopoiesis recovery by a mechanism remaining elusive. This study aimed to investigate at a molecular level a general mechanism underlying DFX beneficial effects on haematopoiesis, both in healthy and pathological conditions. Methods: Human healthy haematopoietic stem/progenitor cells (HS/PCs) and three leukemia cell lines were treated with DFX. N-Acetyl cysteine (NAC) and fludarabine were added as antioxidant and STAT1 inhibitor, respectively. In vitro colony-forming assays were assessed both in healthy and in leukemia cells. Intracellular and mitochondrial reactive oxygen species (ROS) as well as mitochondrial content were assessed by cytofluorimetric and confocal microscopy analysis; mtDNA was assessed by qRT-PCR. Differentiation markers were monitored by cytofluorimetric analysis. Gene expression analysis (GEA) was performed on healthy HS/PCs, and differently expressed genes were validated in healthy and leukemia cells by qRT-PCR. STAT1 expression and phosphorylation were assessed by Western blotting. Data were compared by an unpaired Student t test or one-way ANOVA. Results: DFX, at clinically relevant concentrations, increased the clonogenic capacity of healthy human CD34+ HS/PCs to form erythroid colonies. Extension of this analysis to human-derived leukemia cell lines Kasumi-1, K562 and HL60 confirmed DFX capacity to upregulate the expression of specific markers of haematopoietic commitment. Notably, the abovementioned DFX-induced effects are all prevented by the antioxidant NAC and accompanied with overproduction of mitochondria-generated reactive oxygen species (ROS) and increase of mitochondrial content and mtDNA copy number. GEA unveiled upregulation of genes linked to interferon (IFN) signalling and tracked back to hyper-phosphorylation of STAT1. Treatment of leukemic cell lines with NAC prevented the DFX-mediated phosphorylation of STAT1 as well as the expression of the IFN-stimulated genes. However, STAT1 inhibition by fludarabine was not sufficient to affect differentiation processes in leukemic cell lines. Conclusions: These findings suggest a significant involvement of redox signalling as a major regulator of multiple DFX-orchestrated events promoting differentiation in healthy and tumour cells. The understanding of molecular mechanisms underlying the haematological response by DFX would enable to predict patient's ability to respond to the drug, to extend treatment to other patients or to anticipate the treatment, regardless of the iron overload

    Outcomes after primary and repeat thermal ablation of hepatocellular carcinoma with or without liver transplantation

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    Objectives Thermal ablation (TA) is an established treatment for early HCC. There is a lack of data on the efficacy of repeated TA for recurrent HCC, resulting in uncertainty whether good oncologic outcomes can be obtained without performing orthotopic liver transplantation (OLTx). This study analyses outcomes after TA, with a special focus on repeat TA for recurrent HCC, either as a stand-alone therapy, or in relationship with OLTx. Methods Data from a prospectively registered database on interventions for HCC in a tertiary hepatobiliary centre was completed with follow-up until December 2020. Outcomes studied were rate of recurrence after primary TA and after its repeat interventions, the occurrence of untreatable recurrence, OS and DSS after primary and repeat TA, and complications after TA. In cohorts matched for confounders, OSS and DSS were compared after TA with and without the intention to perform OLTx. Results After TA, 100 patients (56 center dot 8%) developed recurrent HCC, of whom 76 (76 center dot 0%) underwent up to four repeat interventions. During follow-up, 76 center dot 7% of patients never developed a recurrence unamenable to repeat TA or OLTx. OS was comparable after primary TA and repeat TA. In matched cohorts, OS and DSS were comparable after TA with and without the intention to perform OLTx. Conclusions We found TA to be an effective and repeatable therapy for primary and recurrent HCC. Most recurrences can be treated with curative intent. There are patients who do well with TA alone without ever undergoing OLTx

    Non-birational twisted derived equivalences in abelian GLSMs

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    In this paper we discuss some examples of abelian gauged linear sigma models realizing twisted derived equivalences between non-birational spaces, and realizing geometries in novel fashions. Examples of gauged linear sigma models with non-birational Kahler phases are a relatively new phenomenon. Most of our examples involve gauged linear sigma models for complete intersections of quadric hypersurfaces, though we also discuss some more general cases and their interpretation. We also propose a more general understanding of the relationship between Kahler phases of gauged linear sigma models, namely that they are related by (and realize) Kuznetsov's `homological projective duality.' Along the way, we shall see how `noncommutative spaces' (in Kontsevich's sense) are realized physically in gauged linear sigma models, providing examples of new types of conformal field theories. Throughout, the physical realization of stacks plays a key role in interpreting physical structures appearing in GLSMs, and we find that stacks are implicitly much more common in GLSMs than previously realized.Comment: 54 pages, LaTeX; v2: typo fixe

    Hydration and nutrition care practices in stroke: findings from the UK and Australia

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    BACKGROUND: Dehydration and malnutrition are common in hospitalised patients following stroke leading to poor outcomes including increased mortality. Little is known about hydration and nutrition care practices in hospital to avoid dehydration or malnutrition, and how these practices vary in different countries. This study sought to capture how the hydration and nutrition needs of patients' post-stroke are assessed and managed in the United Kingdom (UK) and Australia (AUS).AIM: To examine and compare current in-hospital hydration and nutrition care practice for patients with stroke in the UK and Australia.METHODS: A cross-sectional survey was conducted between April and November 2019. Questionnaires were mailed to stroke specialist nurses in UK and Australian hospitals providing post-stroke inpatient acute care or rehabilitation. Non-respondents were contacted up to five times.RESULTS: We received 150/174 (86%) completed surveys from hospitals in the UK, and 120/162 (74%) in Australia. Of the 270 responding hospitals, 96% reported undertaking assessment of hydration status during an admission, with nurses most likely to complete assessments (85%). The most common methods of admission assessment were visual assessment of the patient (UK 62%; AUS 58%), weight (UK 52%; AUS 52%), and body mass index (UK 47%; AUS 42%). Almost all (99%) sites reported that nutrition status was assessed at some point during admission, and these were mainly completed by nurses (91%). Use of standardised nutrition screening tools were more common in the UK (91%) than Australia (60%). Similar proportions of hydration management decisions were made by physicians (UK 84%; AUS 83%), and nutrition management decisions by dietitians (UK 98%; AUS 97%).CONCLUSION: Despite broadly similar hydration and nutrition care practices after stroke in the UK and Australia, some variability was identified. Although nutrition assessment was more often informed by structured screening tools, the routine assessment of hydration was generally not. Nurses were responsible for assessment and monitoring, while dietitians and physicians undertook decision-making regarding management. Hydration care could be improved through the development of standardised assessment tools. This study highlights the need for increased implementation and use of evidence-based protocols in stroke hydration and nutrition care to improve patient outcomes.</p

    BPS Domain Wall Junctions in Infinitely Large Extra Dimensions

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    We consider models of scalar fields coupled to gravity which are higher-dimensional generalizations of four dimensional supergravity. We use these models to describe domain wall junctions in an anti-de Sitter background. We derive Bogomolnyi equations for the scalar fields from which the walls are constructed and for the metric. From these equations a BPS-like formula for the junction energy can be derived. We demonstrate that such junctions localize gravity in the presence of more than one uncompactified extra dimension.Comment: 17 pages, uses RevTeX, new references adde
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