Disaster Response Project Scheduling Problem: A Resolution Method based on a Game-Theoretical Model

International audienceWe present a particular disaster response project scheduling problem (DRPSP) motivated by Fukushima's nuclear accident of Japan in 2011. We describe the problem as $MPS;R,N \vert prec, d_n \vert \sum c_k f(r_k (S))$ by using Hartmann and Briskorn scheme and formulate a mixed integer linear programming (MILP) model. Due to the NP-hardness of the problem, we propose a resolution method based on game theory. This method associates the DRPSP to a non-cooperative game model, such that game solution is a feasible solution of the problem. In order to explore the potential of the proposed model and the performance of the resolution method, computational experiments are carried out. The results of resolution method show on average, that the method finds a feasible solution with a difference of 15.44% with respect to optimal solution within one percent of the time required by the MILP over GAMS 22.7.2/CPLEX 11.0

Hospitalizations and mortality of patients with heart failure in the COVID-19 era in Peru

Objectives: The worldwide heart failure (HF) prevalence is 8.52 per 1000 inhabitants, with a global economic burden of 346.17 billion dollars. With the COVID-19 pandemic, the focus of medical care has changed to treating the morbidity and mortality of patients with COVID-19 and reducing medical procedures or visits to patients with HF, with the impact being greater in low- and middle-income countries. Methods: We performed an interrupted time series analysis of HF to determine the changes in the trend of hospitalizations and in-hospital mortality of HF patients before and after the mandatory lockdown in Peru. Results: A total of 18,514 adults were included in the analysis. Monthly hospital admissions immediately decreased by 599 (95% confidence interval [CI]: 113 to 1085) and the difference in slope before and after the lockdown was 6.4 hospital admissions (95% CI: −4 to 18). In-hospital mortality increased by 18% (95% CI: −8%–43%) and the difference in slope before and after the lockdown was −0.3% (95% CI: −0.9%–0.25%). Conclusions: There was a reduction in hospitalizations and an increase in the in-hospital mortality of patients with HF before and after the mandatory lockdown due to the COVID-19 pandemic in Peru.Revisión por pare

A comparative study of electrodeposited and vapour deposited gold films : Fractal surface characterization through scanning tunnelling microscopy

The surfaces of Au deposits grown under non-equilibrium conditions from either the electroreduction of Au oxide or from the vapour have been analysed as fractals by measuring the perimeter (P) and the area (A) of intergranular voids. The values of P and A were determined from scanning tunnelling microscopy (STM) topographic imaging of the deposit surfaces. A frsctal behaviour P ∝ 4 D/2 was found with D = 1.5 ± 0.1 and D = 1.7 ± 0.1 for the electrodeposited and vapour deposited Au iilms, respectively. These figures remain constant for film thicknesses between 100 and 1000 mn. The value of D, the fractal dimension of the surfaces, is 2.5 ± 0.1 for the Au electrodeposits, and 2.7 + 0.1 for the Au vapour deposited films. The former value is consistent with either a diffusion or an electric field controlled growth model, whereas the latter is in agreement with a ballistic growth model.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Laparoscopic diaphragmatic plication for paralysis posterior to trauma. Case report

Diaphragmatic paralysis is a pathology characterized by the elevation of a plastic and inactive atrophic diaphragm, followed by an injury to the spinal column or to the phrenic nerve. Because it involves the phrenic nerve, it is often associated with an injury at its exit in the spinal cord at the radicular level, at the conduct or in the peripheral nerve. Clinical case: A 50-year-old male patient with a history of thoracic trauma and diagnosis of unstable thorax is admitted for progressive dyspnea in the following 8 months. Diaphragmatic paralysis is diagnosed and a laparoscopic diaphragmatic plicature is performed. Patient improved his clinical status by 29%. Discussion: The consequences of the elevation of a hemidiaphragm can be respiratory, causing hypoxemia and decreases in the ventilation---perfusion ratio. This procedure is considered a corrective surgery from the morphological and functional point of view. Conclusions: Our patient’s clinical status improved according to the Saint George respiratory questionnaire, thanks to an improved perfusion of the basal lung expansion. Laparoscopic diaphragmatic plicature is a safe procedure associated with a minimal hospital stay, and more cases need to be reported. This is the procedure of choice in our institution

Hydrothermal assisted synthesis of iron oxide-based magnetic silica spheres and their performance in magnetophoretic water purification

Porous Magnetic Silica (PMS) spheres of about 400 nm diameter were synthesised by one-pot process using the classical Stӧber method combined with hydrothermal treatment. Maghemite nanoparticles (γ-Fe2O3) were used as fillers and cetyltrimethylammonium bromide (CTAB) was used as templating agent. The application of the hydrothermal process (120 °C during 48 h) before the calcination leads to the formation of homogeneous and narrow size distribution PMS spheres. X-ray diffraction patterns (XRD), Infrared measurements (FTIR) and Transmission Electron microscopy (TEM) methods were used to determine the composition and morphology of the obtained PMS spheres. The results show a homogeneous distribution of the γ-Fe2O3 nanoparticles in the silica matrix with a “hollow-like” morphology. Magnetophoresis measurements at 60 T m−1 show a total separation time of the PMS spheres suspension of about 16 min. By using this synthesis method, the limitation of the formation of silica spheres without incorporation of magnetic nanoparticles is overcome. These achievements make this procedure interesting for industrial up scaling. The obtained PMS spheres were evaluated as adsorbents for Ni2+ in aqueous solution. Their adsorption capacity was compared with the adsorption capacity of magnetic silica spheres obtained without hydrothermal treatment before calcination process. PMS spheres show an increase of the adsorption capacity of about 15% of the initial dissolution of Ni2+ without the need to functionalize the silica surface.Fundação para a Ciência e a Tecnologia (FCT

Association between emergency department length of stay and adverse perioperative outcomes in emergency surgery: A cohort study in two Colombian University hospitals

Background: In low- and middle-income countries emergency surgery represents a higher proportion of the total number of surgeries and is associated with greater morbidity/mortality. Study aims were to determine if emergency department length of stay (ED-LOS) was associated with adverse perioperative outcomes and if such association varied across patient's risk categories. Methods: A retrospective cohort study was conducted of adult patients who underwent orthopedic or abdominal emergency surgery at two Colombian University hospitals. The population comprised a mix of a representative sample of eligible cases, with unselected patients (2/3), enriched with a high-risk subset (1/3). ED-LOS was defined as the interval between emergency department arrival and surgery start time. Our primary outcome was an adverse perioperative outcome during hospitalization, which was a composite of in-hospital mortality or severe complications such as major cardiovascular adverse events, infection, renal failure and bleeding. Results: Among 1487 patients analyzed, there were 519 adverse perioperative outcomes including 150 deaths. In the unselected sample (n = 998) 17.9% of patients presented an adverse perioperative outcome with a mortality of 4.9%. The median ED-LOS was 24.6 (IQR 12.5-53.2) hours. ED-LOS was associated with age, comorbidities and known risk factors for 30-day mortality. Patients developing an adverse perioperative outcome started surgery 27.1 h later than their counterparts. Prolonged ED-LOS increased the risk of an adverse perioperative outcome in patients without risk factors (covariate-adjusted OR = 2.52), while having 1-2 or 3+ risk factors was negatively associated (OR = 0.87 and 0.72, respectively, p less than 0.001 for the interaction). Conclusion: Prolonged ED-LOS is associated with increased adverse perioperative outcome for patients without risk factors for mortality, but seems protective and medically justified for more complex cases. © 2019 The Author(s)

[Changes in the prevalence of hypertension in Peru using the new guideline of the American College of Cardiology].

INTRODUCTION AND OBJECTIVE: There is little evidence in Latin America about the impact of the ACC/AHA 2017 guideline. Taking as reference the JNC 7 guideline, the objective of our study is to estimate changes in the prevalence of arterial hypertension (HBP) according to socio-demographic characteristics and geographic regions, applying the criteria of the new ACC / AHA guide 2017. METHODS: Cross-sectional study of the Demographic and Family Health Survey conducted in Peru in 2017. Standardized weighted hypertension prevalence's were estimated for the WHO population according to both guidelines, and absolute differences with 95% CI. RESULTS: We included 30,682 people aged 18 years and over, with an average age of 42.3 years, 51.1% women. The standardized prevalence of HBP for 2017 according to JNC 7 was 14.4% (95% CI: 13.8-15.1) and according to ACC / AHA 2017 it was 32.9% (95% CI: 32.0-33.7), so the prevalence increase is 18.5 percentage points, being higher in males than females (24.2 vs 12.9 respectively). In people with obesity and / or who consume tobacco, the increases were higher (24.3 and 24.1 percentage points respectively). In the regions of Tacna, Ica and Metropolitan Lima, the increase, in comparison with the JNC 7 guidelines, overcome the national average (22.4, 20.7 and 20.4, percentage points, respectively). CONCLUSIONS: Considering the context of a Latin American country and knowing the epidemiology of hypertension in Peru, the potential adoption of the ACC/AHA 2017 guidelines for the prevention, detection, evaluation, and management of hypertension should be accompanied by an evaluation of the impact at the individual, system and social level

A comparative study of electrodeposited and vapour deposited gold films : Fractal surface characterization through scanning tunnelling microscopy

The surfaces of Au deposits grown under non-equilibrium conditions from either the electroreduction of Au oxide or from the vapour have been analysed as fractals by measuring the perimeter (P) and the area (A) of intergranular voids. The values of P and A were determined from scanning tunnelling microscopy (STM) topographic imaging of the deposit surfaces. A frsctal behaviour P ∝ 4 D/2 was found with D = 1.5 ± 0.1 and D = 1.7 ± 0.1 for the electrodeposited and vapour deposited Au iilms, respectively. These figures remain constant for film thicknesses between 100 and 1000 mn. The value of D, the fractal dimension of the surfaces, is 2.5 ± 0.1 for the Au electrodeposits, and 2.7 + 0.1 for the Au vapour deposited films. The former value is consistent with either a diffusion or an electric field controlled growth model, whereas the latter is in agreement with a ballistic growth model.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Energía de enlace para una impureza donadora poco profunda en hilos cuánticos rectangulares de GaAs bajo presión hidrostática

RESUMEN: En la aproximación de masa efectiva y usando el método variacional se calcula la energía de enla-ce de una impureza donadora poco profunda en un hilo cuántico de GaAs con sección transversal rectangular bajo presión hidrostática. Los resultados son para diferentes posiciones de la impureza y tamaños de la sección transversal del hilo. Los aspectos más generales que han sido observados pueden ser resumidos así: 1) la energía de enlace decrece con el desplazamiento de la impureza hacia las paredes del hilo, 2) para una sección transversal fija, la energía de enlace se incrementa con el incremento de la presión hidrostática y 3) en los casos límite del tamaño de la sección trans-versal del hilo, los resultados están en buen acuerdo con reportes previos en pozos cuánticos y sis-temas hidrogenoides 3D

Clasificación automática de las vocales en el lenguaje de señas colombiano

Sign language recognition is a highly-complex problem due to the amount of static and dynamic gestures needed to represent such language, especially when it changes from country to country. This article focuses on static recognition of vowels in Colombian Sign Language. A total of 151 images were acquired for each class, and an additional non-vowel class with different scenes was also considered. The object of interest was cut out of the rest of the scene in the captured image by using color information. Subsequently, features were extracted to describe the gesture that corresponds to a vowel or to the class that does not match any vowel. Next, four sets of features were selected. The first one contained all of them; from it, three new sets were generated. The second one was extracted from a subset of features given by the Principal Component Analysis (PCA) algorithm. The third set was obtained by Sequential Feature Selection (SFS) with the FISHER measure. The last set was completed with SFS based on the performance of the K-Nearest Neighbor (KNN) algorithm. Finally, multiple classifiers were tested on each set by cross-validation. Most of the classifiers achieved a performance over 90%, which led to conclude that the proposed method allows an appropriate class distinction.El reconocimiento del lenguaje de señas es un problema de alta complejidad, debido a la cantidad de gestos estáticos y dinámicos necesarios para representar dicho lenguaje, teniendo en cuenta que el mismo variará para cada país en particular. Este artículo se enfoca en el reconocimiento de las vocales del lenguaje colombiano de señas, de forma estática. Se adquirieron 151 imágenes por cada clase, teniendo en cuenta también una clase no vocal adicional con diferentes escenas. A partir de cada imagen capturada se separa el objeto de interés del resto de la escena usando información de color; luego, se extraen características para describir el gesto correspondiente a cada vocal o a la clase que no corresponde a ninguna vocal. Posteriormente, se seleccionan cuatro conjuntos de características. El primero con la totalidad de ellas; a partir de este salen tres nuevos conjuntos: el segundo extrayendo un subconjunto de características mediante el algoritmo de Análisis de Componentes Principales (PCA). El tercer conjunto, aplicando Selección Secuencial hacia Adelante (SFS), mediante la medida de FISHER y el último conjunto con SFS basado en el desempeño del clasificador de los vecinos más cercanos (KNN). Finalmente se prueban múltiples clasificadores para cada conjunto por medio de validación cruzada, obteniendo un desempeño superior al 90% para la mayoría de los clasificadores, concluyendo que la metodología propuesta permite una adecuada separación de las clases