Fasting in critical illness: the role of ketonuria - a retrospective observational study.

Background: Metabolic acidosis is a frequent finding in patients admitted to the intensive care unit (ICU). It can be caused by prolonged fasting due to surgical procedures or by medical conditions that lead to starvation ketoacidosis (SKA). Early recognition and treatment of SKA could prevent several life-threatening complications, improving survival and reducing the ICU length of stay.

Nucleation of helium in pure liquid lithium.

Tritium self-sufficiency in fusion nuclear reactors will be based on the neutron capture by lithium in the so-called breeding blankets of the reactor, a nuclear reaction that will produce helium along with tritium. The low solubility of helium in liquid metals could cause the eventual formation of helium bubbles, which may have a negative impact on the performance of the breeding blanket in a way that has yet to be fully understood. In this work, we provide deep insight into the behavior of lithium and helium mixtures at experimentally operating conditions (800 K and pressures between 1 and 100 bars) using a microscopic model suitable to describe the interactions between helium and lithium at the atomic level, in excellent agreement with available experimental data.

Nucleation of Helium in Liquid Lithium at 843 K and High Pressures.

Fusion energy stands out as a promising alternative for a future decarbonised energy system. In order to be sustainable, future fusion nuclear reactors will have to produce their own tritium. In the so-called breeding blanket of a reactor, the neutron bombardment of lithium will produce the desired tritium, but also helium, which can trigger nucleation mechanisms owing to the very low solubility of helium in liquid metals.

Weighted contrastive divergence.

Learning algorithms for energy based Boltzmann architectures that rely on gradient descent are in general computationally prohibitive, typically due to the exponential number of terms involved in computing the partition function. In this way one has to resort to approximation schemes for the evaluation of the gradient. This is the case of Restricted Boltzmann Machines (RBM) and its learning algorithm Contrastive Divergence (CD).

Dipolar Bose Supersolid Stripes.

We study the superfluid properties of a system of fully polarized dipolar bosons moving in the XY plane. We focus on the general case where the polarization field forms an arbitrary angle α with respect to the Z axis, while the system is still stable. We use the diffusion Monte Carlo and the path integral ground state methods to evaluate the one-body density matrix and the superfluid fractions in the region of the phase diagram where the system forms stripes.

Elements of kitchen toxicology to exploit the value of traditional (African) recipes: The case of meal in the diet of HIV+/AIDS subjects.

The soup is a traditional African meal that is considered of high nutritional value and protective against weight loss. We introduce the concept of "kitchen toxicology" to analyse the recipe of the soup and highlight possible mitigation measures for toxic and/or antinutritional effects in the wide spectrum of health and nutritional needs of HIV+/AIDS subjects. In particular, we focus on toxicants (environmental contaminants, process contaminants, substances leaching from food contact materials) dysregulating the immune status, as well as on interactions between nutrients, contaminants, and/or antinutrients which may lead to secondary/conditioned nutritional deficiencies or imbalances; in their turn, these can modulate the ability to cope with toxicants, and increase nutritional requirements.

Droplets of Trapped Quantum Dipolar Bosons.

Strongly interacting systems of dipolar bosons in three dimensions confined by harmonic traps are analyzed using the exact path integral ground-state Monte Carlo method. By adding a repulsive two-body potential, we find a narrow window of interaction parameters leading to stable ground-state configurations of droplets in a crystalline arrangement. We find that this effect is entirely due to the interaction present in the Hamiltonian without resorting to additional stabilizing mechanisms or specific three-body forces.

Quantum Monte Carlo estimation of complex-time correlations for the study of the ground-state dynamic structure function.

We present a method based on the path integral Monte Carlo formalism for the calculation of ground-state time correlation functions in quantum systems. The key point of the method is the consideration of time as a complex variable whose phase δ acts as an adjustable parameter. By using high-order approximations for the quantum propagator, it is possible to obtain Monte Carlo data all the way from purely imaginary time to δ values near the limit of real time.

Lifetime estimation of a zirconia-alumina composite for biomedical applications.

Objectives: In this work long term stability of a zirconia toughened alumina (ZTA) composite was investigated.

Methods: Accelerated aging tests under hydrothermal environment, in autoclave and hot water, at different temperature, was conducted on material sample. Tetragonal to monoclinic transformation was evaluated by XRD analysis and the monoclinic content was plot as a function of the exposure time.

Excitations and stripe phase formation in a two-dimensional dipolar Bose gas with tilted polarization.

We present calculations of the ground state and excitations of an anisotropic dipolar Bose gas in two dimensions, realized by a nonperpendicular polarization with respect to the system plane. For sufficiently high density, an increase of the polarization angle leads to a density instability of the gas phase in the direction where the anisotropic interaction is strongest. Using a dynamic many-body theory, we calculate the dynamic structure function in the gas phase which shows the anisotropic dispersion of the excitations.

High-order time expansion path integral ground state.

The feasibility of path integral Monte Carlo ground state calculations with very few beads using a high-order short-time Green's function expansion is discussed. An explicit expression of the evolution operator which provides dramatic enhancements in the quality of ground-state wave functions is examined. The efficiency of the method makes possible to remove the trial wave function and thus obtain completely model-independent results still with a very small number of beads.

Dynamics of a two-dimensional system of quantum dipoles.

A detailed microscopic analysis of the dynamic structure function S(k,omega) of a two-dimensional Bose system of dipoles polarized along the direction perpendicular to the plane is presented and discussed. Starting from ground-state quantities obtained using a quantum diffusion Monte Carlo algorithm, the density-density response is evaluated in the context of the correlated basis functions (CBF) theory. CBF predicts a sharp peak and a multiexcitation component at higher energies produced by the decay of excitations.

Boltzmann machines reduction by high-order decimation.

Decimation is a common technique in statistical physics that is used in the context of Boltzmann machines (BMs) to drastically reduce the computational cost at the learning stage. Decimation allows to analytically evaluate quantities that should otherwise be statistically estimated by means of Monte Carlo (MC) simulations. However, in its original formulation, this method could only be applied to restricted topologies corresponding to sparsely connected neural networks.

Ground-state properties of a one-dimensional system of hard rods.

A quantum Monte Carlo simulation of a system of bosonic hard rods in one dimension is presented and discussed. The calculation is exact since the analytical form of the wave function is known and is in excellent agreement with predictions obtained from asymptotic expansions valid at large distances. The analysis of the static structure factor and the pair distribution function indicates that a solidlike and a gaslike phases exist at high and low densities, respectively.

High-momentum response of liquid 3He.

A final-state-effects formalism suitable to analyze the high-momentum response of Fermi liquids is presented and used to study the dynamic structure function of liquid 3He. The theory, developed as a natural extension of the Gersch-Rodriguez formalism, incorporates the Fermi statistics explicitly through a new additive term which depends on the semidiagonal two-body density matrix. The use of a realistic momentum distribution, calculated using the diffusion Monte Carlo method, and the inclusion of this additive correction allows for good agreement with available deep-inelastic neutron scattering data.

Dissociation of responsiveness to thyrotropin-releasing hormone and thyroid suppressibility following antithyroid drug therapy of hyperthyroidism.

Responsiveness to synthetic thyrotropin-releasing hormone (TRH), thyroid suppressibility by triiodothyronine (T3) and the outcome of hyperthyroidism following prolonged therapy with thionamides were studied in a group of 35 patients with toxic diffuse goiter. TRH and T3 suppression tests were performed 10 days to 24 months (mean 4 months) after withdrawal of antithyroid drugs. Nineteen patients were euthyroid and had a normal thyrotropin (TSH) response to TRH, while 4 were recovering from mild hypothyroidism due to overtreatment and had an exaggerated response.