For (n+1)-dimensional asymptotically anti-de Sitter (AdS) spacetimes which have holographic duals on their n-dimensional conformal boundaries, we show that the imposition of causality on the boundary theory is sufficient to prove positivity of mass for the spacetime when n> or =3, without the assumption of any local energy condition. We make crucial use of a time-delay formula relating the Ashtekar-Magnon mass of the spacetime to the time delay of a bulk null curve relative to that of a boundary null geodesic. We also discuss holographic causality for the negative mass AdS soliton and its implications for the positive energy conjecture of Horowitz and Myers.
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http://dx.doi.org/10.1103/PhysRevLett.89.121301 | DOI Listing |
Cell Mol Biol (Noisy-le-grand)
November 2024
Department of Gynecology, Military University Hospital and 3rd Faculty of Medicine, U Vojenske nemocnice Nemocnice 1200, 169 02 Prague 6, Czech Republic.
Circulating endometrial cells (CECs) have emerged as a new biomarker of advanced disease in women with endometriosis. The identification of several subtypes of CECs (e.g.
View Article and Find Full Text PDFSci Robot
October 2024
Program in Molecular Medicine, Hospital for Sick Children, Toronto, ON, Canada.
Arrhythmogenic cardiomyopathy (ACM) is a leading cause of sudden cardiac death among young adults. Aberrant gap junction remodeling has been linked to disease-causative mutations in plakophilin-2 (). Although gap junctions are a key therapeutic target, measurement of gap junction function in preclinical disease models is technically challenging.
View Article and Find Full Text PDFCell Commun Signal
October 2024
Institute of Molecular Medicine, National Cheng Kung University, Tainan, 70101, Taiwan.
Background: Normal cells express functional tumor suppressor WW domain-containing oxidoreductase (WWOX), designated WWOXf. UV irradiation induces WWOXf cells to undergo bubbling cell death (BCD) - an event due to the accumulation of nuclear nitric oxide (NO) gas that forcefully pushes the nuclear and cell membranes to form one or two bubbles at room temperature (22 °C) and below. In contrast, when WWOX-deficient or -dysfunctional (WWOXd) cells are exposed to UV and/or cold shock, the cells undergo nuclear pop-out explosion death (POD).
View Article and Find Full Text PDFbioRxiv
August 2024
Department of Neuroscience, University of California, Berkeley.
Observation of neural firing patterns can constrain theories for the types of activity patterns that the brain uses to guide behavior. However, directly perturbing these patterns, ideally with great specificity, is required to causally test any particular theory. We combined two-photon imaging and cellular resolution optogenetic photo-stimulation to causally test how neural activity in the mouse visual cortex is read out to detect visual stimuli.
View Article and Find Full Text PDFNature
October 2024
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
Continuous attractors are an emergent property of neural population dynamics that have been hypothesized to encode continuous variables such as head direction and eye position. In mammals, direct evidence of neural implementation of a continuous attractor has been hindered by the challenge of targeting perturbations to specific neurons within contributing ensembles. Dynamical systems modelling has revealed that neurons in the hypothalamus exhibit approximate line-attractor dynamics in male mice during aggressive encounters.
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