36 research outputs found
Conformal Covariance and the Split Property
No full textWe show that for a conformal local net of observables on the circle, the split property is automatic. Both full conformal covariance (i.e., diffeomorphism covariance) and the circle-setting play essential roles in this fact, while by previously constructed examples it was already known that even on the circle, Möbius covariance does not imply the split property. On the other hand, here we also provide an example of a local conformal net living on the 2-dimensional Minkowski space, which—although being diffeomorphism covariant—does not have the split property. © 2017 The Author(s
The Modular Hamiltonian in Asymptotically Flat Spacetime Conformal to Minkowski
No full textWe consider a four-dimensional globally hyperbolic and asymptotically flat spacetime (M, g) conformal to Minkowski spacetime, together with a massless, conformally coupled scalar field. Using a bulk-to-boundary correspondence, one can establish the existence of an injective ∗-homomorphism ΥM between W(M), the Weyl algebra of observables on M and a counterpart which is defined intrinsically on future null infinity I+≃R×S2, a component of the conformal boundary of (M, g). Using invariance under the asymptotic symmetry group of I+, we can individuate thereon a distinguished two-point correlation function whose pull-back to M via ΥM identifies a quasi-free Hadamard state for the bulk algebra of observables. In this setting, if we consider Vx+, a future light cone stemming from x∈M as well as W(Vx+)=W(M)|Vx+, its counterpart at the boundary is the Weyl subalgebra generated by suitable functions localized in Kx, a positive half strip on I+. To each such cone, we associate a standard subspace of the boundary one-particle Hilbert space, which coincides with the one associated naturally to Kx. We extend such correspondence replacing Kx and Vx+ with deformed counterparts, denoted by SC and VC. In addition, since the one particle Hilbert space at the boundary decomposes as a direct integral on the sphere of U(1)-currents defined on the real line, we prove that also the generator of the modular group associated to the standard subspace of VC decomposes as a suitable direct integral. This result allows us to study the relative entropy between coherent states of the algebras associated to the deformed cones VC establishing the quantum null energy condition
Split Property for Free Massless Finite Helicity Fields
No full textWe prove the split property for any finite helicity free quantum fields. Finite helicity Poincaré representations extend to the conformal group C (cf. Mack in Commun Math Phys 55:1–28, 1977) and the conformal covariance plays an essential role in the argument: The split property is ensured by the trace class condition Tr(e-βL0)<∞ for the conformal Hamiltonian L of the Möbius covariant restriction of the net on the time axis. We extend the argument for the scalar case presented in Buchholz et al. (Commun Math Phys 270:267–293, 2007). We provide the direct sum decomposition into irreducible representations of the conformal extension of any helicity-h representation to the subgroup of transformations fixing the time axis. Our analysis provides new relations among finite helicity representations and suggests a new construction for representations and free quantum fields with nonzero helicity
Recensione a: Codex Diplomaticus Cavensis. XI (1081-1085) e XII (1086-1090), a cura di Carmine Carlone, Leone Morinelli e Giovanni Vitolo, Battipaglia (SA), Laveglia&Carlone, 2015.
No full textI due volumi appena pubblicati del Codex Diplomaticus Cavensis, XI (1081-1085) e XII (1086-1090), a cura di C. Carlone, L. Morinelli e G. Vitolo, aggiungono un ulteriore tassello a quel potenziale informativo che la pubblicazione integrale dell’intero corpus documentario cavense potrà in futuro restituire
Breast Cancer Oncological Outcomes at an Italian Center Following Nipple-Sparing and Skin-Sparing Mastectomy Techniques
No full textBackground: The introduction of skin-sparing mastectomy (SSM) and nipple-sparing mastectomy (NSM) with immediate reconstruction allowed a noticeable improvement in reconstructive surgery aesthetic results and patients' psychophysical well-being. In any case, there are still concerns about the long-term oncological safety of these two procedures. This study aims to assess the oncological outcomes of women who underwent SSM and NSM and to compare them with traditional modified total mastectomy (MTM). The secondary outcome was to compare mastectomy with breast-conserving surgery (BCS) outcome. Methods: We performed a retrospective chart review study concerning all patients who had experienced SSM and NSM in our Clinic between January 2004 and July 2013. The main outcomes were overall survival (OS), disease-free survival (DFS), and recurrences cumulative rate. Results: Among this study's 1836 invasive breast carcinomas, we found NSM (86.7, 95% confidence interval (CI), 76.7-98.0%) to have a significantly shorter 5-year DFS than MTM (90.4%, 95% CI, 87.9-93.0%). Furthermore, low body mass index (odds ratio (OR) 0.733, p = 0.056), basal-like molecular subtype (OR 28.932, p < 0.05), extended intraductal component (OR 11.160, p = 0.107), and lymph node metastasis extracapsular invasion (OR 8.727, p = 0.077) were the most significant predictors of recurrence in women treated with NSM. Furthermore, patients with BCS had significantly longer OS and DFS than those who underwent MTM. Conclusions: Occult nipple neoplastic involvement following negative intraoperative histological examination of subareolar tissue may explain the higher recurrence rate among women undergoing NSM. Patients with one or more risk factors for recurrence after NSM, such as basal-like molecular subtype, extended intraductal component, and extracapsular invasion of lymph node metastasis, should be given special attention
Degradation of EEG microstates patterns in subjective cognitive decline and mild cognitive impairment: Early biomarkers along the Alzheimer's Disease continuum?
No full textAlzheimer's disease (AD) pathological changes may begin up to decades earlier than the appearance of the first symptoms of cognitive decline. Subjective cognitive decline (SCD) could be the first pre-clinical sign of possible AD, which might be followed by mild cognitive impairment (MCI), the initial stage of clinical cognitive decline. However, the neural correlates of these prodromic stages are not completely clear yet. Recent studies suggest that EEG analysis tools characterizing the cortical activity as a whole, such as microstates and cortical regions connectivity, might support a characterization of SCD and MCI conditions. Here we test this approach by performing a broad set of analyses to identify the prominent EEG markers differentiating SCD (n = 57), MCI (n = 46) and healthy control subjects (HC, n = 19). We found that the salient differences were in the temporal structure of the microstates patterns, with MCI being associated with less complex sequences due to the altered transition probability, frequency and duration of canonic microstate C. Spectral content of EEG, network connectivity, and spatial arrangement of microstates were instead largely similar in the three groups. Interestingly, comparing properties of EEG microstates in different cerebrospinal fluid (CSF) biomarkers profiles, we found that canonic microstate C displayed significant differences in topography in AD-like profile. These results show that the progression of dementia might be associated with a degradation of the cortical organization captured by microstates analysis, and that this leads to altered transitions between cortical states. Overall, our approach paves the way for the use of non-invasive EEG recordings in the identification of possible biomarkers of progression to AD from its prodromal states
Unraveling the Membrane Topology of TMEM151A: A Step Towards Understanding its Cellular Role
No full textTransmembrane protein 151A (TMEM151A) has been identified as a causative gene for paroxysmal kinesigenic dyskinesia, though its molecular function remains almost completely unknown. Understanding the membrane topology of transmembrane proteins is crucial for elucidating their functions and possible interacting partners. In this study, we utilized molecular dynamics simulations, immunocytochemistry, and electron microscopy to define the topology of TMEM151A. Our results validate a starting AlphaFold model of TMEM151A and reveal that it comprises a transmembrane domain with two membrane-spanning alpha helices connected by a short extracellular loop and an intramembrane helix-hinge-helix structure. Notably, most of the protein is oriented towards the intracellular side of the membranes with a large cytosolic domain featuring a combination of alpha-helix and beta-sheet structures, as well as the protein N- and C-termini. These insights into TMEM151A's topology and orientation of its domains with respect of the cell membranes provide essential information for future functional studies and represent a first fundamental step for understanding its role in the pathogenesis of paroxysmal kinesigenic dyskinesia
Degradation of EEG microstates patterns in subjective cognitive decline and mild cognitive impairment: Early biomarkers along the Alzheimer's Disease continuum?
No full textAlzheimer's disease (AD) pathological changes may begin up to decades earlier than the appearance of the first symptoms of cognitive decline. Subjective cognitive decline (SCD) could be the first pre-clinical sign of possible AD, which might be followed by mild cognitive impairment (MCI), the initial stage of clinical cognitive decline. However, the neural correlates of these prodromic stages are not completely clear yet. Recent studies suggest that EEG analysis tools characterizing the cortical activity as a whole, such as microstates and cortical regions connectivity, might support a characterization of SCD and MCI conditions. Here we test this approach by performing a broad set of analyses to identify the prominent EEG markers differentiating SCD (n = 57), MCI (n = 46) and healthy control subjects (HC, n = 19). We found that the salient differences were in the temporal structure of the microstates patterns, with MCI being associated with less complex sequences due to the altered transition probability, frequency and duration of canonic microstate C. Spectral content of EEG, network connectivity, and spatial arrangement of microstates were instead largely similar in the three groups. Interestingly, comparing properties of EEG microstates in different cerebrospinal fluid (CSF) biomarkers profiles, we found that canonic microstate C displayed significant differences in topography in AD-like profile. These results show that the progression of dementia might be associated with a degradation of the cortical organization captured by microstates analysis, and that this leads to altered transitions between cortical states. Overall, our approach paves the way for the use of non-invasive EEG recordings in the identification of possible biomarkers of progression to AD from its prodromal states
