1,341 research outputs found
Superconductivity-Induced Anderson Localisation
We have studied the effect of a random superconducting order parameter on the
localization of quasi-particles, by numerical finite size scaling of the
Bogoliubov-de Gennes tight-binding Hamiltonian. Anderson localization is
obtained in d=2 and a mobility edge where the states localize is observed in
d=3. The critical behavior and localization exponent are universal within error
bars both for real and complex random order parameter. Experimentally these
results imply a suppression of the electronic contribution to thermal transport
from states above the bulk energy gap.Comment: 4 pages, revtex file, 3 postscript figure
Targeted DamID in C. elegans reveals a direct role for LIN-22 and NHR-25 in antagonising the epidermal stem cell fate
Transcription factors are key players in gene networks controlling cell fate specification during development. In multicellular organisms, they often display complex patterns of expression and binding to their targets, hence tissue-specificity is required in the characterisation of transcription factor-target interactions. We introduce here Targeted DamID (TaDa) as a method for tissue-specific transcription factor target identification in intact C. elegans animals. We employ TaDa to recover targets in the epidermis for two key transcription factors, the HES1 homologue LIN-22 and the NR5A1/2 nuclear hormone receptor NHR-25. We demonstrate a direct link between LIN-22 and the Wnt signalling pathway through repression of the Frizzled receptor lin-17. We also find a direct role for NHR-25 in promoting cell differentiation via repressing the expression of stem cell-promoting GATA factors. Our results expand our understanding of the epidermal gene network and highlight the potential of TaDa to dissect the architecture of tissue-specific gene regulatory networks
Distributed Sum-Rate Maximization of Cellular Communications with Multiple Reconfigurable Intelligent Surfaces
The technology of Reconfigurable Intelligent Surfaces (RISs) has lately
attracted considerable interest from both academia and industry as a low-cost
solution for coverage extension and signal propagation control. In this paper,
we study the downlink of a multi-cell wideband communication system comprising
single-antenna Base Stations (BSs) and their associated single-antenna users,
as well as multiple passive RISs. We assume that each BS controls a separate
RIS and performs Orthogonal Frequency Division Multiplexing (OFDM)
transmissions. Differently from various previous works where the RIS unit
elements are considered as frequency-flat phase shifters, we model them as
Lorentzian resonators and present a joint design of the BSs' power allocation,
as well as the phase profiles of the multiple RISs, targeting the sum-rate
maximization of the multi-cell system. We formulate a challenging distributed
nonconvex optimization problem, which is solved via successive concave
approximation. The distributed implementation of the proposed design is
discussed, and the presented simulation results showcase the interplay of the
various system parameters on the sum rate, verifying the performance boosting
role of RISs.Comment: 5 pages, 1 figure. Presented in IEEE SPAWC 202
© Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License. Natural Hazards
Relationship between lightning and model simulated microphysical parameters over the central and eastern Mediterranea
Diagnosis and outcome of oesophageal Crohn's disease
BACKGROUND AND AIMS:
Crohn's disease (CD) can involve any part of the gastrointestinal tract. We aimed to characterize clinical, endoscopic, histologic features and treatment outcomes of CD patients with oesophageal involvement.
METHODS:
We collected cases through a retrospective multicentre European Crohn's and Colitis Organisation CONFER [COllaborative Network For Exceptionally Rare case reports] project. Clinical data were recorded in a standardized case report form.
RESULTS:
A total of 40 patients were reported [22 males, mean (±SD, range) age at oesophageal CD diagnosis: 25 (±13.3, 10-71) years and mean time of follow-up: 67 (±68.1, 3-240) months]. Oesophageal involvement was established at CD diagnosis in 26 patients (65%) and during follow-up in 14. CD was exclusively located in the oesophagus in 2 patients. Thirteen patients (32.2%) were asymptomatic at oesophageal disease diagnosis. Oesophageal strictures were present in 5 patients and fistulizing oesophageal disease in one. Eight patients exhibited granulomas on biopsies. Proton-pump inhibitors (PPIs) were administered in 37 patients (92.5%). Three patients underwent endoscopic dilation for symptomatic strictures and none oesophageal-related surgery. Diagnosis in pre-established CD resulted in treatment modifications in 9/14 patients. Clinical remission of oesophageal disease was seen in 33/40 patients (82.5%) after a mean time of 7 (±5.6, 1-18) months. Follow-up endoscopy was performed in 29/40 patients and 26/29 (89.7%) achieved mucosal healing.
CONCLUSION:
In this case series the endoscopic and histologic characteristics of isolated oesophageal CD were similar to those reported in other sites of involvement. Treatment was primarily conservative, with PPIs administered in the majority of patients and modifications in pre-existing IBD-related therapy occurring in two thirds of them. Clinical and endoscopic remission was achieved in more than 80% of the patients.info:eu-repo/semantics/publishedVersio
Power Minimizing MEC Offloading with QoS Constraints over RIS-Empowered Communications
This work lies at the intersection of two cutting edge technologies
envisioned to proliferate in future 6G wireless systems: Multi-access Edge
Computing (MEC) and Reconfigurable Intelligent Surfaces (RISs). While the
former will bring a powerful information technology environment at the wireless
edge, the latter will enhance communication performance, thanks to the
possibility of adapting wireless propagation as per end users' convenience,
according to specific service requirements. We propose a joint optimization of
radio, computing, and wireless environment reconfiguration through an RIS, with
the goal of enabling low power computation offloading services with reliability
guarantees. Going beyond previous works on this topic, multi-carrier frequency
selective RIS elements' responses and wireless channels are considered. This
opens new challenges in RIS optimization, accounting for frequency dependent
RIS response profiles, which strongly affect RIS-aided wireless links and, as a
consequence, MEC service performance. We formulate an optimization problem
accounting for short and long-term constraints involving device transmit power
allocation across multiple subcarriers and local computing resources, as well
as RIS reconfiguration parameters according to a recently developed Lorentzian
model. Besides a theoretical optimization framework, numerical results show the
effectiveness of the proposed method in enabling low power reliable computation
offloading over RIS-aided frequency selective channels.Comment: IEEE GLOBECOM 202
Efficacy and Safety of Oral Factor XIa Inhibitors in Stroke Prevention: A Systematic Review and Meta-Analysis
Anticoagulation; Factor Xia inhibitors; Ischemic strokeAnticoagulació; Inhibidors del factor Xia; Ictus isquèmicAnticoagulación; Inhibidores del factor Xia; Ictus isquémicoIntroduction: Despite preventive measures, stroke rates remain high in the primary and secondary prevention settings. Factor XIa inhibition may offer a novel, safe and effective antithrombotic option for stroke prevention. Methods: We conducted a systematic review and meta-analysis including all available randomized controlled clinical trials (RCTs) that investigated the efficacy and safety of factor XIa inhibitors versus controls in primary or secondary stroke prevention. The primary efficacy and safety outcomes of interest were symptomatic ischemic stroke (IS) and the composite of major bleeding and clinically relevant non-major bleeding. Results: Four phase II dose-finding RCTs were included, comprising a total of 4732 patients treated with factor XIa inhibitors versus 1798 controls. Treatment with factor XIa inhibitors did not reduce the risk of IS compared to controls (RR: 0.89; 95% CI: 0.67–1.17). The composite of symptomatic IS and covert infarcts on brain MRI (RR: 1.01; 95% CI: 0.87–1.18), the composite of symptomatic IS and transient ischemic attack (TIA; RR: 0.78; 95% CI: 0.61–1.01), and the composite of major adverse cardiovascular events (RR: 1.07; 95% CI: 0.87–1.31) did not differ between the treatment groups. Treatment with factor XIa inhibitors did not increase the risk of the composite of major bleeding and clinically relevant non-major bleeding (RR: 1.19; 95% CI: 0.65–2.16), major bleeding alone (RR: 1.19; 95% CI: 0.64–2.22), intracranial bleeding (RR: 0.91; 95% CI: 0.26–3.19) or all-cause mortality (RR: 1.21; 95% CI: 0.77–1.90). Conclusion: This meta-analysis provides reassuring evidence regarding the safety of factor XIa inhibitors. These findings, coupled with potential signals of efficacy in reducing IS (and TIA), underscore the importance of ongoing phase III RCTs for providing definitive data regarding the effect of factor XIa inhibition on stroke prevention
Relationship between lightning and model simulated microphysical parameters over the central and eastern Mediterranean
Aubert Marcel. Lejeaux (Jeanne). Sculpture religieuse (Bibliothèque catholique des sciences religieuses), 1934. In: Bulletin Monumental, tome 93, n°2, année 1934. pp. 267-268
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