Telephone Assessment of Suicidal Risk at Prehospital Emergency Medical Services: A Direct Comparison with Face-to-Face Evaluation at Psychiatric Emergency Service.

OBJECTIVE: Assessment of suicidal risk is one of the most challenging tasks faced by health professionals, notably in emergency care. We compared telephone suicide risk assessment at prehospital Emergency Medical Services Dispatch Center (EMS-DC), with subsequent face-to-face evaluation at Psychiatric Emergency Service (PES), using French national Risk-Urgency-Danger standards (RUD). METHOD: Data were collected for all suicidal adult patients (N = 80) who were addressed by EMS-DC to PES between December 2018 and August 2019 and benefited from RUD assessment at both services. Suicidal risk was given a score of 1, 2, 3 or 4, in order of severity. RESULTS: Mean of the differences between the RUD score at EMS-DC and PES was -0.825 (SD = 1.19), and was found to be significant (p < 0.01). The average time between RUD assessments was 420 min (SD = 448) and was negatively correlated with the difference in the RUD score (r = -0.295, p = 0.008). Associated suicide attempt increased the odds of a decrease in the RUD score (OR = 2.989; 95% CI = 1.141-8.069; p < 0.05). CONCLUSIONS: Telephone evaluation of suicidal risk using RUD at EMS-DC yielded moderately higher scores than those obtained by a subsequent face-to face evaluation at PES, with this difference partially explained by the time between assessments, and by clinical and contextual factors.

On Deterministic and Stochastic Multiple Pathogen Epidemic Models.

In this paper, we consider a stochastic epidemic model with two pathogens. In order to analyze the coexistence of two pathogens, we compute numerically the expectation time until extinction (the mean persistence time), which satisfies a stationary partial differential equation with degenerate variable coefficients, related to backward Kolmogorov equation. I use the finite element method in order to solve this equation, and we implement it in FreeFem++. The main conclusion of this paper is that the deterministic and stochastic epidemic models differ considerably in predicting coexistence of the two diseases and in the extinction outcome of one of them. Now, the main challenge would be to find an explanation for this result.

Global self-regulation of the cellular metabolic structure.

BACKGROUND: Different studies have shown that cellular enzymatic activities are able to self-organize spontaneously, forming a metabolic core of reactive processes that remain active under different growth conditions while the rest of the molecular catalytic reactions exhibit structural plasticity. This global cellular metabolic structure appears to be an intrinsic characteristic common to all cellular organisms. Recent work performed with dissipative metabolic networks has shown that the fundamental element for the spontaneous emergence of this global self-organized enzymatic structure could be the number of catalytic elements in the metabolic networks. METHODOLOGY/PRINCIPAL FINDINGS: In order to investigate the factors that may affect the catalytic dynamics under a global metabolic structure characterized by the presence of metabolic cores we have studied different transitions in catalytic patterns belonging to a dissipative metabolic network. The data were analyzed using non-linear dynamics tools: power spectra, reconstructed attractors, long-term correlations, maximum Lyapunov exponent and Approximate Entropy; and we have found the emergence of self-regulation phenomena during the transitions in the metabolic activities. CONCLUSIONS/SIGNIFICANCE: The analysis has also shown that the chaotic numerical series analyzed correspond to the fractional Brownian motion and they exhibit long-term correlations and low Approximate Entropy indicating a high level of predictability and information during the self-regulation of the metabolic transitions. The results illustrate some aspects of the mechanisms behind the emergence of the metabolic self-regulation processes, which may constitute an important property of the global structure of the cellular metabolism.

The number of catalytic elements is crucial for the emergence of metabolic cores.

BACKGROUND: Different studies show evidence that several unicellular organisms display a cellular metabolic structure characterized by a set of enzymes which are always in an active state (metabolic core), while the rest of the molecular catalytic reactions exhibit on-off changing states. This self-organized enzymatic configuration seems to be an intrinsic characteristic of metabolism, common to all living cellular organisms. In a recent analysis performed with dissipative metabolic networks (DMNs) we have shown that this global functional structure emerges in metabolic networks with a relatively high number of catalytic elements, under particular conditions of enzymatic covalent regulatory activity. METHODOLOGY/PRINCIPAL FINDINGS: Here, to investigate the mechanism behind the emergence of this supramolecular organization of enzymes, we have performed extensive DMNs simulations (around 15,210,000 networks) taking into account the proportion of the allosterically regulated enzymes and covalent enzymes present in the networks, the variation in the number of substrate fluxes and regulatory signals per catalytic element, as well as the random selection of the catalytic elements that receive substrate fluxes from the exterior. The numerical approximations obtained show that the percentages of DMNs with metabolic cores grow with the number of catalytic elements, converging to 100% for all cases. CONCLUSIONS/SIGNIFICANCE: The results show evidence that the fundamental factor for the spontaneous emergence of this global self-organized enzymatic structure is the number of catalytic elements in the metabolic networks. Our analysis corroborates and expands on our previous studies illustrating a crucial property of the global structure of the cellular metabolism. These results also offer important insights into the mechanisms which ensure the robustness and stability of living cells.