104 research outputs found

    On the Tensionless Limit of Bosonic Strings, Infinite Symmetries and Higher Spins

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    In the tensionless limit of string theory on flat background all the massive tower of states gets squeezed to a common zero mass level and the free theory is described by an infinite amount of massless free fields with arbitrary integer high spin. We notice that in this situation the very notion of critical dimension gets lost, the apparency of infinite global symmetries takes place, and the closed tensionless string can be realized as a constrained subsystem of the open one in a natural way. Moreover, we study the tensionless limit of the Witten's cubic sting field theory and find that the theory in such a limit can be represented as an infinite set of free arbitrary higher spin excitations plus an interacting sector involving their zero-modes only.Comment: 1+17 pages. Typos corrected and references adde

    Computed tomography-based identification of ganglionated plexi to guide cardioneuroablation for vasovagal syncope

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    This study shows that CT-based EFP-guided CNA for CI-VVS is feasible, can assist RF delivery with high precision, and has the potential to overcome the interpatient variability that affects CNA when performed solely by anatomic landmarks. Further larger studies with longer follow-up are required to improve CT-based identification of GPs and our understanding of GP pathophysiology

    Clinical impact of aging on outcomes of cardioneuroablation for reflex syncope or functional bradycardia. Results from the cardionEuroabLation: patiEnt selection, imaGe integrAtioN and outComEs. The ELEGANCE multicenter study

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    Background: Cardioneuroablation (CNA) is a novel treatment for reflex syncope. The effect of aging on CNA efficacy is not fully understood. Objective: We assessed the impact of aging on candidacy and efficacy of CNA for treating vasovagal syncope (VVS), carotid sinus syndrome (CSS) and functional bradyarrhythmia. Methods: The ELEGANCE multicenter study assessed CNA in patients with reflex syncope or severe functional bradyarrhythmia. Patients underwent pre-CNA Holter ECG, head-up tilt testing (HUT) and electrophysiologic study. CNA candidacy and efficacy was assessed in 14 young (18-40 years), 26 middle-aged (41-60 years) and 20 older (>60 years) patients. Results: Sixty patients (37 men; mean age: 51±16 years) underwent CNA. The majority (80%) had VVS, 8% CSS, and 12% functional bradycardia/AV block. Pre-CNA Holter ECG, HUT and EP findings did not differ across age groups. Acute CNA success was 93%, without differences between age groups (p=0.42). Post-CNA HUT response was negative in 53%, vasodepressor in 38%, cardioinhibitory in 7% and mixed in 2%, without differences across age groups (p=0.59). At follow-up (8 months, IQR:4-15), 53 (88%) patients were free of symptoms. Kaplan-Meier curves did not show differences in event-free survival between age groups (p=0.29). The negative predictive value of a negative HUT was 91.7%. Conclusions: CNA is a viable treatment for reflex syncope and functional bradyarrhythmia in all ages, and is highly effective in mixed VVS. HUT is a key-step of post-ablation clinical assessment

    On the covariant quantization of tensionless bosonic strings in AdS spacetime

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    The covariant quantization of the tensionless free bosonic (open and closed) strings in AdS spaces is obtained. This is done by representing the AdS space as an hyperboloid in a flat auxiliary space and by studying the resulting string constrained hamiltonian system in the tensionless limit. It turns out that the constraint algebra simplifies in the tensionless case in such a way that the closed BRST quantization can be formulated and the theory admits then an explicit covariant quantization scheme. This holds for any value of the dimension of the AdS space.Comment: 1+16 pages; v4 two clarifications adde

    How future surgery will benefit from SARS-COV-2-related measures: a SPIGC survey conveying the perspective of Italian surgeons

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    COVID-19 negatively affected surgical activity, but the potential benefits resulting from adopted measures remain unclear. The aim of this study was to evaluate the change in surgical activity and potential benefit from COVID-19 measures in perspective of Italian surgeons on behalf of SPIGC. A nationwide online survey on surgical practice before, during, and after COVID-19 pandemic was conducted in March-April 2022 (NCT:05323851). Effects of COVID-19 hospital-related measures on surgical patients' management and personal professional development across surgical specialties were explored. Data on demographics, pre-operative/peri-operative/post-operative management, and professional development were collected. Outcomes were matched with the corresponding volume. Four hundred and seventy-three respondents were included in final analysis across 14 surgical specialties. Since SARS-CoV-2 pandemic, application of telematic consultations (4.1% vs. 21.6%; p < 0.0001) and diagnostic evaluations (16.4% vs. 42.2%; p < 0.0001) increased. Elective surgical activities significantly reduced and surgeons opted more frequently for conservative management with a possible indication for elective (26.3% vs. 35.7%; p < 0.0001) or urgent (20.4% vs. 38.5%; p < 0.0001) surgery. All new COVID-related measures are perceived to be maintained in the future. Surgeons' personal education online increased from 12.6% (pre-COVID) to 86.6% (post-COVID; p < 0.0001). Online educational activities are considered a beneficial effect from COVID pandemic (56.4%). COVID-19 had a great impact on surgical specialties, with significant reduction of operation volume. However, some forced changes turned out to be benefits. Isolation measures pushed the use of telemedicine and telemetric devices for outpatient practice and favored communication for educational purposes and surgeon-patient/family communication. From the Italian surgeons' perspective, COVID-related measures will continue to influence future surgical clinical practice

    CMS physics technical design report : Addendum on high density QCD with heavy ions

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