A macroeconomic model of an epidemic with silent transmission and endogenous self-isolation.

I study the interaction between epidemics and economic decisions in a model where: (i) agents allocate their time to market and home production and social and home leisure, (ii) these activities differ in their degree of contagiousness, (iii) some infected individuals are indistinguishable from susceptible individuals and (iv) agents are not necessarily rational. For baseline parameter values for the COVID-19 pandemic, I find that agents partially self-isolate by allocating more time to home activities and that the effective reproduction number of the disease stabilizes at 1. Detection and isolation of infected individuals severely mitigate the recession and deaths caused by the pandemic.

Modèle macroéconomique d'une épidémie avec transmission silencieuse et isolement volontaire endogène. Dans cet article, j'étudie les liens entre les épidémies et les décisions économiques à l'aide d'un modèle dans lequel : (i) les agents répartissent leur temps entre la production d'un bien marchand et la production d'un bien domestique ainsi quéntre des activités sociales et des loisirs à domicile; (ii) ces activités varient quant à leur degré de contagiosité; (iii) certains individus infectés ne se distinguent en rien des personnes vulnérables et (iv) les agents ne sont pas nécessairement rationnels. En ce qui concerne les valeurs des paramètres de base de la COVID­19, je constate que les agents s'isolent partiellement en consacrant davantage de temps à des activités domestiques, et que le taux de reproduction effectif se stabilise aux alentours de un. Le dépistage et l'isolement des individus infectés atténuent fortement la récession engendrée par la pandémie.

Effectiveness of a hydrophobic dressing for microorganisms' colonization of vascular ulcers: Protocol for a randomized controlled trial (CUCO-UV Study).

AIM: To determine the effectiveness of a hydrophobic dressing (Cutimed Sorbact® ) against a silver dressing (Aquacel® Ag Extra) in the level of colonization of chronic venous leg ulcers. The secondary endpoints are health-related quality of life, level of pain, and time to complete healing. DESIGN: Open randomized controlled trial, with blinded endpoint. METHODS: Patients with chronic venous leg ulcers with signs of critical colonization will be randomized in a concealed sequence using computer software to receive one of the alternative dressings. A total of 204 participants recruited in Primary Health Care and nursing homes will be necessary to assure statistical power. Measures will include sociodemographic variables, wound-related variables (area, exudate, and time to healing), level of pain, adverse effects, and health-related quality of life. Smear samples will be collected from the ulcers and will be subject to DNA-typing technique through polymerase chain reaction to obtain the level of colony-forming units. Measures will be collected at baseline, 4, 8, and 12 weeks. DISCUSSION: Elevated levels of microorganisms prevent wound healing and favour its chronification. The main target when colonization is present is to reduce the bacterial load to levels that promote immune system mobilization. Hydrophobic dressings prevent the formation of biofilm in the wound by means of physical effect, so that the possibility of antimicrobial resistance is significantly reduced. IMPACT: Current evidence about the effectiveness of dressings to minimize venous leg ulcers colonization is very limited. Previous studies have important methodological flaws. This study will permit to obtain the effectiveness of hydrophobic dressings against silver dressings with a robust design based on conditions of routine clinical practice in Primary Health Care and nursing homes.

Predicting induced activity in the Havar foils of the (18)F production targets of a PET cyclotron and derived radiological risk.

The PET cyclotron at the Centre of Molecular Imaging of the Universidad de Malaga (CIMES) is a 16.5 MeV GE PETtrace cyclotron working at dual beam (40 µA beam). The cyclotron is dedicated mainly to F production. The F target has two thin circular foils composed of a metal alloy (Havar), that are highly activated by the proton beam and secondary neutrons. The main purpose of this study is to assess induced activity radiological risk derived from the Havar foils activation. Induced activity in Havar foils was estimated by two procedures. One consisted in estimating neutron and proton fluxes with MCNPX and using them as inputs in the activation code ACAB. Alternatively, given the regular periodicity of the irradiation cycles, an analytical expression was derived to estimate activity concentrations of activation products using production rates calculated with MCNPX. Large differences were found in the induced foil activities predicted by the two procedures. Therefore, an irradiated vacuum foil was measured with a Ge detector to analyze activity levels. Cobalt-58 (Co) and Co activities calculated with ACAB match well with measurements. Cobalt-60 (Co) activity estimated with the alternative method agrees acceptably with the measured activity, and Co activity is slightly overestimated. Cobalt-57 (Co) is the activation product of concern in the long term. The vacuum and window foils will be exempted in 3.3 y and 5.5 y, respectively, after replacement. Calculated effective dose with MCNPX and ICRP reference HML phantoms in the foils replacement operation is 0.34 mSv, and annual effective dose would be 2.1 mSv, which is below the annual limits.

Prediction of neutron induced radioactivity in the concrete walls of a PET cyclotron vault room with MCNPX.

PURPOSE: The authors want to assess the relevance of the neutron activation of the concrete vault of the PET cyclotron at CIMES (Universidad de Malaga) by predicting specific activities of the main activation products in the vault and their variation profiles as a function of penetration depth into concrete at present and after 10 yr of cyclotron operation. METHODS: The dual proton cyclotron is used for PET isotopes production, mainly 18F. During the years 2006 and 2008, the using rate has been 1 h/day at single beam (40 microA). From January 2008, using rate is 4 h/day at dual beam (80 microA). The energy of the cyclotron proton beam is 18 MeV. Four point locations were chosen on the walls of the cyclotron room to assess neutron induced activity concentrations. In each wall point location, neutron induced radionuclide specific activity was assessed from the wall surface to a depth of 120 cm within concrete. Simulations were carried out with the Monte Carlo based radiation transport code MCNPX (v2.6.0). RESULTS: According to MCNPX calculations, activity depth profiles of activation products studied, except 54Mn, have a maximum at variable depths from the wall surface never beyond 12 cm. 54Mn activity decreases exponentially in all the studied depth ranges within wall concrete. The activity of 152Eu, 154Eu, 60CO, 134Cs, 46Sc, and 65Zn decreases exponentially beyond a 30 cm depth into concrete. 54Mn activity presents the faster decrease within a concrete vault with an attenuation length of 21 cm. According to MCNPX estimations, present activity in the cyclotron vault is mostly due to 46Sc and 60Co, with highest specific activity near the vault surface of 146 +/- 16 and 50 +/- 4.6 Bq/kg, respectively. 46Sc and 60Co activity measurements near the surface wall present an acceptable match with the estimation within the uncertainties, but measured activities of the other radionuclides are quite over the MCNPX estimations. The calculations after 10 yr of cyclotron operation predict a slight increase for short half-life radionuclides (46Sc, 54Mn, and 65Zn). However, long half-life neutron induced radionuclides importantly increase their activities, especially 60Co and 152Eu. These radionuclides and 46Sc give the main contribution to the wall activity in a 10 yr period. Estimated highest 46Sc and 60Co activities in 10 yr of cyclotron operation are in acceptable agreement with published measurements, but MCNPX calculated activities are lower than the measurements for the rest of the radionuclides. CONCLUSIONS: MCNPX estimates acceptably present activity levels of 46Sc and 60Co as confirmed by activity measurements, but underestimates activity for the rest of the neutron induced radionuclides in the wall. Activity measurements have revealed the inhomogeneity of wall concrete atomic composition since large differences in activity values were found in two near wall surface locations with similar neutron flux. Such inhomogeneity cannot be modeled with the program that considers the material composition homogeneous. Highest specific activities estimated in a 10 yr operation are under exemption limits and therefore the cyclotron vault can be discarded as radioactive waste.