148 research outputs found
Dissipation-driven generation of two-qubit entanglement mediated by plasmonic waveguides
We study the generation of entanglement between two distant qubits mediated
by the surface plasmons of a metallic waveguide. We show that a V-shaped
channel milled in a flat metallic surface is much more efficient for this
purpose than a metallic cylinder. The role of the misalignments of the dipole
moments of the qubits, an aspect of great importance for experimental
implementations, is also studied. A careful analysis of the quantum-dynamics of
the system by means of a master equation shows that two-qubit entanglement
generation is essentially due to the dissipative part of the effective
qubit-qubit coupling provided by the surface plasmons. The influence of a
coherent external pumping, needed to achieve a steady state entanglement, is
discussed. Finally, we pay attention to the question of how to get information
experimentally on the degree of entanglement achieved in the system.Comment: 13 pages, 12 figure
Aperiodicity in one-way Markov cycles and repeat times of large earthquakes in faults
A common use of Markov Chains is the simulation of the seismic cycle in a
fault, i.e. as a renewal model for the repetition of its characteristic
earthquakes. This representation is consistent with Reid's elastic rebound
theory. Here it is proved that in {\it any} one-way Markov cycle, the
aperiodicity of the corresponding distribution of cycle lengths is always lower
than one. This fact concurs with observations of large earthquakes in faults
all over the world
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLVIII-M-2-2023 29th CIPA Symposium âDocumenting, Understanding, Preserving Cultural Heritage: Humanities and Digital Technologies for Shaping the Futureâ, 25â30 June 2023, Florence, Italy
The VETTONIA project aims to disseminate the rich heritage from the Iron Age of the western Iberian Peninsula and the archaeological investigations carried out on this topic in recent years. The project utilizes new technologies such as virtual tours, 3D models, and impressions to create interactive and stimulating ways to access the results of the most recent archaeological research. Using these resources, lectures and seminars are being given in various forums with diverse types of audiences to present the virtual tours and the rest of the dissemination initiatives. In addition, the project presents its different initiatives during the annual archaeological interventions developed in the oppidum of Ulaca (Solosancho, Ăvila, Spain), with good reception by the attending public. The VETTONIA project represents a pioneering dissemination experience that takes advantage of the educational opportunities offered by new technologies. In the future, tools such as virtual tours to archaeological sites may prove essential in classroom teaching at different levels and could promote sustainable tourism in fragile natural environments such as those that constitute the major settlements of the Late Iron Age (ca. 400â50 BC)
VETTONIA PROJECT: A VIRTUAL ENVIRONMENT FOR THE EDUCATIONAL DISSEMINATION OF THE IRON AGE
The VETTONIA project aims to disseminate the rich heritage from the Iron Age of the western Iberian Peninsula and the archaeological investigations carried out on this topic in recent years. The project utilizes new technologies such as virtual tours, 3D models, and impressions to create interactive and stimulating ways to access the results of the most recent archaeological research. Using these resources, lectures and seminars are being given in various forums with diverse types of audiences to present the virtual tours and the rest of the dissemination initiatives. In addition, the project presents its different initiatives during the annual archaeological interventions developed in the oppidum of Ulaca (Solosancho, Ăvila, Spain), with good reception by the attending public. The VETTONIA project represents a pioneering dissemination experience that takes advantage of the educational opportunities offered by new technologies. In the future, tools such as virtual tours to archaeological sites may prove essential in classroom teaching at different levels and could promote sustainable tourism in fragile natural environments such as those that constitute the major settlements of the Late Iron Age (ca. 400â50 BC)
Quality changes and shelf-life prediction of a fresh fruit and vegetables purple smoothie
The sensory, microbial and bioactive quality changes of untreated (CTRL) and mild heatâtreated (HT; 90 ÂșC/45 s) smoothies were studied and modelled throughout storage (5, 15 and 25 ÂșC). The overall acceptability was better preserved in HT samples being highly correlated (hierarchical clustering) with the flavour. The sensory quality data estimated smoothie shelfâlife (CTRL/HT) of 18/55 (at 5 ÂșC), 4.5/12 (at 15 ÂșC), 2.4/5.8 (at 25 ÂșC) days. The yeast and moulds growth rate was lower in HT compared to CTRL while a lag phase for mesophiles/psychrophiles was observed in HTâ5/15 ÂșC. HT and 5 ÂșCâstorage stabilized the phenolics content. FRAP reported the best correlation (R2=0.94) with the studied bioactive compounds, followed by ABTS (R2=0.81) while DPPH was the total antioxidant capacity method with the lowest adjustment (R2=0.49). Conclusively, modelling was used to estimate the shelfâlife of a smoothie based on quality retention after a short timeâhigh temperature heat treatment that better preserved microbial and nutritional quality during storage.The financial support of this research was provided by the Ministerio Español de EconomĂa y Competitividad MINECO (Projects AGL2013â48830âC2â1âR and AGL2013â48993âC2â1âR) and by FEDER funds. G.A. GonzĂĄlezâTejedor thanks to PanamĂĄ Government for the scholarship to carry out his PhD Thesis. A. Garre (BESâ2014â070946) is grateful to the MINECO for awarding him a preâdoctoral grant. We are also grateful to E. Esposito and N. Castillejo for their skilful technical assistance
Dynamical Boson Stars
The idea of stable, localized bundles of energy has strong appeal as a model
for particles. In the 1950s John Wheeler envisioned such bundles as smooth
configurations of electromagnetic energy that he called {\em geons}, but none
were found. Instead, particle-like solutions were found in the late 1960s with
the addition of a scalar field, and these were given the name {\em boson
stars}. Since then, boson stars find use in a wide variety of models as sources
of dark matter, as black hole mimickers, in simple models of binary systems,
and as a tool in finding black holes in higher dimensions with only a single
killing vector. We discuss important varieties of boson stars, their dynamic
properties, and some of their uses, concentrating on recent efforts.Comment: 79 pages, 25 figures, invited review for Living Reviews in
Relativity; major revision in 201
MICa/b-dependent activation of natural killer cells by CD64+ inflammatory type 2 dendritic cells contributes to autoimmunity.
Primary Sjögren's syndrome (pSS) is an inflammatory autoimmune disorder largely mediated by type I and II interferon (IFN). The potential contribution of innate immune cells, such as natural killer (NK) cells and dendritic cells (DC), to the pSS pathology remains understudied. Here, we identified an enriched CD16+ CD56hi NK cell subset associated with higher cytotoxic function, as well as elevated proportions of inflammatory CD64+ conventional dendritic cell (cDC2) subtype that expresses increased levels of MICa/b, the ligand for the activating receptor NKG2D, in pSS individuals. Circulating cDC2 from pSS patients efficiently induced activation of cytotoxic NK cells ex vivo and were found in proximity to CD56+ NK cells in salivary glands (SG) from pSS patients. Interestingly, transcriptional activation of IFN signatures associated with the RIG-I/DDX60 pathway, IFN I receptor, and its target genes regulate the expression of NKG2D ligands on cDC2 from pSS patients. Finally, increased proportions of CD64hi RAE-1+ cDC2 and NKG2D+ CD11b+ CD27+ NK cells were present in vivo in the SG after poly I:C injection. Our study provides novel insight into the contribution and interplay of NK and cDC2 in pSS pathology and identifies new potential therapy targets.S
Nucleophile-Catalyzed Additions to Activated Triple Bonds. Protection of Lactams, Imides, and Nucleosides with MocVinyl and Related Groups
Additions of lactams, imides, (S)-4-benzyl-1,3-oxazolidin-2-one, 2-pyridone, pyrimidine-2,4-diones (AZT derivatives), or inosines to the electron-deficient triple bonds of methyl propynoate, tert-butyl propynoate, 3-butyn-2-one, N-propynoylmorpholine, or N-methoxy-N-methylpropynamide in the presence of many potential catalysts were examined. DABCO and, second, DMAP appeared to be the best (highest reaction rates and E/Z ratios), while RuCl3, RuClCp*(PPh3)2, AuCl, AuCl(PPh3), CuI, and Cu2(OTf)2 were incapable of catalyzing such additions. The groups incorporated (for example, the 2-(methoxycarbonyl)ethenyl group that we name MocVinyl) serve as protecting groups for the above-mentioned heterocyclic CONH or CONHCO moieties. Deprotections were accomplished via exchange with good nucleophiles: the 1-dodecanethiolate anion turned out to be the most general and efficient reagent, but in some particular cases other nucleophiles also worked (e.g., MocVinyl-inosines can be cleaved with succinimide anion). Some structural and mechanistic details have been accounted for with the help of DFT and MP2 calculations
Severe manifestations of SARS-CoV-2 in children and adolescents: from COVID-19 pneumonia to multisystem inflammatory syndrome: a multicentre study in pediatric intensive care units in Spain
Background
Multisystem inflammatory syndrome temporally associated with COVID-19 (MIS-C) has been described as a novel and often severe presentation of SARS-CoV-2 infection in children. We aimed to describe the characteristics of children admitted to Pediatric Intensive Care Units (PICUs) presenting with MIS-C in comparison with those admitted with SARS-CoV-2 infection with other features such as COVID-19 pneumonia.
Methods
A multicentric prospective national registry including 47 PICUs was carried out. Data from children admitted with confirmed SARS-CoV-2 infection or fulfilling MIS-C criteria (with or without SARS-CoV-2 PCR confirmation) were collected. Clinical, laboratory and therapeutic features between MIS-C and non-MIS-C patients were compared.
Results
Seventy-four children were recruited. Sixty-one percent met MIS-C definition. MIS-C patients were older than non-MIS-C patients (pâ=â0.002): 9.4 years (IQR 5.5â11.8) vs 3.4 years (IQR 0.4â9.4). A higher proportion of them had no previous medical history of interest (88.2% vs 51.7%, pâ=â0.005). Non-MIS-C patients presented more frequently with respiratory distress (60.7% vs 13.3%, pâ<â0.001). MIS-C patients showed higher prevalence of fever (95.6% vs 64.3%, pâ<â0.001), diarrhea (66.7% vs 11.5%, pâ<â0.001), vomits (71.1% vs 23.1%, pâ=â0.001), fatigue (65.9% vs 36%, pâ=â0.016), shock (84.4% vs 13.8%, pâ<â0.001) and cardiac dysfunction (53.3% vs 10.3%, pâ=â0.001). MIS-C group had a lower lymphocyte count (pâ<â0.001) and LDH (pâ=â0.001) but higher neutrophil count (pâ=â0.045), neutrophil/lymphocyte ratio (pâ<â0.001), C-reactive protein (pâ<â0.001) and procalcitonin (pâ<â0.001). Patients in the MIS-C group were less likely to receive invasive ventilation (13.3% vs 41.4%, pâ=â0.005) but were more often treated with vasoactive drugs (66.7% vs 24.1%, pâ<â0.001), corticosteroids (80% vs 44.8%, pâ=â0.003) and immunoglobulins (51.1% vs 6.9%, pâ<â0.001). Most patients were discharged from PICU by the end of data collection with a median length of stay of 5 days (IQR 2.5â8 days) in the MIS-C group. Three patients died, none of them belonged to the MIS-C group.
Conclusions
MIS-C seems to be the most frequent presentation among critically ill children with SARS-CoV-2 infection. MIS-C patients are older and usually healthy. They show a higher prevalence of gastrointestinal symptoms and shock and are more likely to receive vasoactive drugs and immunomodulators and less likely to need mechanical ventilation than non-MIS-C patients
Characteristics and Outcomes in Patients With COVID-19 and Acute Ischemic Stroke: The Global COVID-19 Stroke Registry
Recent case-series of small size implied a pathophysiological association between coronavirus disease 2019 (COVID-19) and severe large-vessel acute ischemic stroke. Given that severe strokes are typically associated with poor prognosis and can be very efficiently treated with recanalization techniques, confirmation of this putative association is urgently warranted in a large representative patient cohort to alert stroke clinicians, and inform pre- and in-hospital acute stroke patient pathways. We pooled all consecutive patients hospitalized with laboratory-confirmed COVID-19 and acute ischemic stroke in 28 sites from 16 countries. To assess whether stroke severity and outcomes (assessed at discharge or at the latest assessment for those patients still hospitalized) in patients with acute ischemic stroke are different between patients with COVID-19 and non-COVID-19, we performed 1:1 propensity score matching analyses of our COVID-19 patients with non-COVID-19 patients registered in the Acute Stroke Registry and Analysis of Lausanne Registry between 2003 and 2019. Between January 27, 2020, and May 19, 2020, 174 patients (median age 71.2 years; 37.9% females) with COVID-19 and acute ischemic stroke were hospitalized (median of 12 patients per site). The median National Institutes of Health Stroke Scale was 10 (interquartile range [IQR], 4-18). In the 1:1 matched sample of 336 patients with COVID-19 and non-COVID-19, the median National Institutes of Health Stroke Scale was higher in patients with COVID-19 (10 [IQR, 4-18] versus 6 [IQR, 3-14]), P=0.03; (odds ratio, 1.69 [95% CI, 1.08-2.65] for higher National Institutes of Health Stroke Scale score). There were 48 (27.6%) deaths, of which 22 were attributed to COVID-19 and 26 to stroke. Among 96 survivors with available information about disability status, 49 (51%) had severe disability at discharge. In the propensity score-matched population (n=330), patients with COVID-19 had higher risk for severe disability (median mRS 4 [IQR, 2-6] versus 2 [IQR, 1-4], P<0.001) and death (odds ratio, 4.3 [95% CI, 2.22-8.30]) compared with patients without COVID-19. Our findings suggest that COVID-19 associated ischemic strokes are more severe with worse functional outcome and higher mortality than non-COVID-19 ischemic strokes
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