Melting and metallization of silica in the cores of gas giants, ice giants and super Earths

The physical state and properties of silicates at conditions encountered in the cores of gas giants, ice giants and of Earth like exoplanets now discovered with masses up to several times the mass of the Earth remains mostly unknown. Here, we report on theoretical predictions of the properties of silica, SiO$_2$, up to 4 TPa and about 20,000K using first principle molecular dynamics simulations based on density functional theory. For conditions found in the Super-Earths and in ice giants, we show that silica remains a poor electrical conductor up to 10 Mbar due to an increase in the Si-O coordination with pressure. For Jupiter and Saturn cores, we find that MgSiO$_3$ silicate has not only dissociated into MgO and SiO$_2$, as shown in previous studies, but that these two phases have likely differentiated to lead to a core made of liquid SiO$_2$ and solid (Mg,Fe)O.Comment: 5 pages, 4 figure

Breast reduction and subsequent cancer: a prophylactic perspective

The aim of this paper was to evaluate the impact of breast-gland remodelling, for cosmetic or functional purposes, on cancer incidence during long-term post-surgical follow-up. We reviewed the literature investigating the ratio between the amount of breast tissue resected and cancer incidence during follow-up. Our analysis of the published data suggested that hypertrophic breast remodelling decreases the risk of breast and other types of cancer in post-operative patients. The actual risk reduction for patients over 40 years of age is related to the weight of the surgical specimens during the previous operation. Our conclusions support the use of breast-reduction surgery as a preventive measure in patients complaining of symptomatic breast enlargement, especially those with a family history of breast cancer

Recent advances in laser-plasma experiments using foams

The paper discusses recent advances in the use of foams in laser–plasma experiments, concerning in particular: (1) the use of foam in order to get an efficient smoothing of laser energy deposition, (2) the problem of hydrodynamics of layered foam-payload targets, (3) the use of foam for shock pressure amplification in equation-of-state experiments, (4) the study of the equation of state of foams in the Megabar regime, and (5) the use of foams for astrophysics relevant experiments, here in particular shock acceleration experiments

Delayed nipple-sparing modified subcutaneous mastectomy: Rationale and technique

The problem of nipple-areola complex (NAC) preservation during mastectomy is a very intriguing and stimulating issue. In fact, in order to perform an oncologically safe operation, no mammary tissue (enclosed in the main galactophoric ducts) should remain; on the other hand, without the blood supply coming from the breast gland, NAC viability is greatly impaired because the surrounding vascular dermal network is not developed enough to support its metabolic requirements. We suggest therefore a two-step surgical procedure. The first step, on an outpatient basis with local tumescent anesthesia, is a mini-invasive cutting and coagulating procedure. It addresses the autonomization of the vascular supply to the NAC by detaching the galactophore stalk from the nipple and coagulating the deep vascular plexus. The second step, under general anesthesia and again with tumescent technique, removes the breast within its capsule, with careful checks of any remnant and adequate approach to the axilla. A subpectoralis prosthesis completes the procedure. In our view, this technique is electively suitable for prophylactic mastectomy, but also for stage I breast cancer, 2.5 cm from the NAC and 1.5 cm from the skin and pectoralis fascia, and it is very safe, simple, and effective

Design of absolute equation of state measurements in optically thick materials by laser-driven shock waves

Abstract Some aspects of the design of a target for the absolute measurement of Equation-of-State data at pressure of tens of Mbar, in optically thick materials are discussed. In the proposed experiment, a shock wave is generated in a laser-irradiated sample, and the shock velocity and the material velocity behind the shock are simultaneously measured by the optical and X-ray diagnostics. Accurate measurements require the generation of a steady, planar shock, and the detection of the motion of a shocked fluid interface by transverse radiography. One- and two-dimensional numerical fluid simulations have been performed to optimize beam and target design, in order to fulfil such requirements

Uncover the Offensive Side of Disparagement Humor: An fMRI Study

Disparagement humor is a kind of humor that denigrates, belittles an individual or a social group. In the aim to unveil the offensive side of these kinds of jokes, we have run an event-related fMRI study asking 30 healthy volunteers to judge the level of fun of a series of verbal stimuli that ended with a sentence that was socially inappropriate but funny (disparagement joke -DJ), socially inappropriate but not funny (SI) or neutral (N). Behavioral results showed disparagement jokes are perceived as funny and at the same time offensive. However, the level of offense in DJ is lower than that registered in SI stimuli. Functional data showed that DJ activated the insula, the SMA, the precuneus, the ACC, the dorsal striatum (the caudate nucleus), and the thalamus. These activations suggest that in DJ a feeling of mirth (and/or a desire to laugh) derived from the joke (e.g., SMA and precuneus) and the perception of the jokes\u2019 social inappropriateness (e.g., ACC and insula) coexist. Furthermore, DJ and SI share a common network related to mentalizing and to the processing of negative feelings, namely the medial prefrontal cortex, the putamen and the right thalamus

Simulation of preheating effects in shock wave experiments

We have analyzed the shock wave propagation experiments performed at LULI and presented at ECLIM'94. The targets were aluminium foils with thickness from 5 to 25 μm. Simulations were performed with the SARA-1D multigroup radiation code. We have shown a small level of preheating caused by the absorption of X-rays with energies close to the K-edge of aluminum. Several sets of opacities were used in order to study this effect, including experimental values for cold aluminum. Simulations show a small level of visible emission induced by X-ray preheating before the arrival of the shock

Decaying shock studies of phase transitions in MgOSiO2 systems: implications for the Super-Earths interiors

We report an experimental study of the phase diagrams of periclase (MgO), enstatite (MgSiO3) and forsterite (Mg2SiO4) at high pressures. We investigated with laser driven decaying shocks the pressure/temperature curves of MgO, MgSiO3 and Mg2SiO4 between 0.2-1.2 TPa, 0.12-0.5 TPa and 0.2-0.85 TPa respectively. A melting signature has been observed in MgO at 0.47 TPa and 9860 K, while no phase changes were observed neither in MgSiO3 nor in Mg2SiO4. An increasing of reflectivity of MgO, MgSiO3 and Mg2SiO4 liquids have been detected at 0.55 TPa -12 760 K, 0.15 TPa - 7540 K, 0.2 TPa - 5800 K, respectively. In contrast to SiO2, melting and metallization of these compounds do not coincide implying the presence of poor electrically conducting liquids close to the melting lines. This has important implications for the generation of dynamos in Super-earths mantles