We discuss the effect of gravitational interactions on the lifetime of the Higgs vacuum where generic quantum gravity corrections are taken into account. Using a "thin-wall" approximation, we provide ...a proof of principle that small black holes can act as seeds for vacuum decay, spontaneously nucleating a new Higgs phase centered on the black hole with a lifetime measured in millions of Planck times rather than billions of years. The corresponding parameter space constraints are, however, extremely stringent; therefore, we also present numerical evidence suggesting that with thick walls, the parameter space may open up. Implications for collider black holes are discussed.
Timing is a fundamental issue in development, with a range of implications from birth defects to evolution. In the roundworm Caenorhabditis elegans, the heterochronic genes encode components of a ...molecular developmental timing mechanism. This mechanism functions in diverse cell types throughout the animal to specify cell fates at each larval stage. MicroRNAs play an important role in this mechanism by stage-specifically repressing cell-fate regulators. Recent studies reveal the surprising complexity surrounding this regulation — for example, a positive feedback loop may make the regulation more robust, and certain components of the mechanism are expressed in brief periods at each stage. Other factors reveal the potential for important roles of steroid hormones and targeted proteolysis. Investigation of the heterochronic genes has revealed a mechanism composed of precisely timed switches linked to discrete developmental stages. Timing is a dimension of developmental regulation that may be difficult to witness in vertebrates because developmental stages are not as discrete as in C. elegans, each tissue is likely to be independently regulated. Homologs of certain heterochronic genes of vertebrates show temporally regulated expression patterns, and may ultimately reveal timing mechanisms not previously known to exist.
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bstract
Static oscillating bounces in Schwarzschild de Sitter spacetime are investigated. The oscillating bounce with many oscillations gives a super-thick bubble wall, for which the total vacuum ...energy increases while the mass of the black hole decreases due to the conservation of Arnowitt-Deser-Misner (ADM) mass. We show that the transition rate of such an “up-tunneling” consuming the seed black hole is higher than that of the Hawking- Moss transition. The correspondence of analyses in the static and global coordinates in the Euclidean de Sitter space is also investigated.
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bstract
Understanding the Higgs potential at large field values corresponding to scales in the range above 10
10
GeV is important for questions of vacuum stability, particularly in the early ...universe where survival of the Higgs vacuum can be an issue. In this paper we show that the Higgs potential can be derived in away which is independent of the choice of conformal frame for the spacetime metric. Questions about vacuum stability can therefore be answered unambiguously. We show that frame independence leads to new relations between the beta functions of the theory and we give improved limits on the allowed values of the Higgs curvature coupling for stability.
We study the gravitational collapse of axion dark matter in null coordinates, assuming spherical symmetry. Compared with previous studies, we use a simpler numerical scheme which can run, for ...relevant parameters, in a few minutes or less on a desktop computer. We use it to accurately determine the domains of parameter space in which the axion field forms a black hole, an axion star or a relativistic Bosenova.
Bubble nucleation in a cold spin 1 gas Billam, Thomas P; Brown, Kate; Moss, Ian G
New journal of physics,
04/2023, Letnik:
25, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Abstract
Cold atomic gases offer the prospect of simulating the physics of the very early Universe in the laboratory. In the condensate phase, the gas is described by a field theory with key features ...of high energy particle theory. This paper describes a three level system which undergoes a first order phase transition through the nucleation of bubbles. The theoretical investigation shows bubbles nucleating in two dimensions at non-zero temperature. There is good agreement between the bubble nucleation rates calculated from a stochastic projected Gross–Pitaevskii equation and from a non-perturbative instanton method. When an optical box trap is included in the simulations, the bubbles nucleate preferentially near the walls of the trap.
Neural progenitor cells (NPCs) have distinct proliferation capacities at different stages of brain development. Lin28 is an RNA-binding protein with two homologs in mice: Lin28a and Lin28b. Here we ...show that Lin28a/b are enriched in early NPCs and their expression declines during neural differentiation. Lin28a single-knockout mice show reduced NPC proliferation, enhanced cell cycle exit and a smaller brain, whereas mice lacking both Lin28a alleles and one Lin28b allele display similar but more severe phenotypes. Ectopic expression of Lin28a in mice results in increased NPC proliferation, NPC numbers and brain size. Mechanistically, Lin28a physically and functionally interacts with Imp1 (Igf2bp1) and regulates Igf2-mTOR signaling. The function of Lin28a/b in NPCs could be attributed, at least in part, to the regulation of their mRNA targets that encode Igf1r and Hmga2. Thus, Lin28a and Lin28b have overlapping functions in temporally regulating NPC proliferation during early brain development.
Please cite this paper as: Moss J, Cooper K, Khaund A, Murray L, Murray G, Wu O, Craig L, Lumsden M. Randomised comparison of uterine artery embolisation (UAE) with surgical treatment in patients ...with symptomatic uterine fibroids (REST trial): 5‐year results. BJOG 2011;118:936–944.
Objective To compare the long‐term results of uterine artery embolisation (UAE) with surgery for women with symptomatic uterine fibroids.
Design Pragmatic, open, multicentre, randomised trial.
Setting Twenty‐seven participating UK secondary care centres.
Sample Women aged ≥18 years with symptomatic fibroids who were considered to justify surgical treatment.
Methods In total, 157 women were randomised (in a 2:1 ratio): 106 to UAE and 51 to surgery (hysterectomy 42; myomectomy nine).
Main outcome measures Quality of life at 5 years, as assessed by the Short Form General Health Survey (SF‐36). Secondary measures included complications, adverse events and the need for further intervention.
Results There were no significant differences between groups in any of the eight components of the SF‐36 scores at 5 years (minimum P = 0.45). Symptom score reduction and patient satisfaction with either treatment was very high, with no group difference. Rates of adverse events were similar in both groups (19% embolization and 25% surgery; P = 0.40). The 5‐year intervention rate for treatment failure or complications was 32% (UAE arm) and 4% (surgery arm), respectively. The initial cost benefit of UAE over surgery at 12 months was substantially reduced because of subsequent interventions, with treatments being cost neutral at 5 years.
Conclusions We have found that UAE is a satisfactory alternative to surgery for fibroids. The less invasive nature of UAE needs to be balanced against the need for re‐intervention in almost a third of patients. The choice should lie with the informed patient.
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