Optimal Reactive Power Compensation in Distribution Networks with Radial and Meshed Structures Using D-STATCOMs: A Mixed-Integer Convex Approach.

This paper deals with the problem regarding the optimal siting and sizing of distribution static compensators (D-STATCOMs) in electrical distribution networks to minimize the expected total annual operating costs. These costs are associated with the investments made in D-STATCOMs and expected energy losses costs. To represent the electrical behavior of the distribution networks, a power flow formulation is used which includes voltages, currents, and power as variables via incidence matrix representation. This formulation generates a mixed-integer nonlinear programming (MINLP) model that accurately represents the studied problem. However, in light of the complexities involved in solving this MINLP model efficiently, this research proposes a mixed-integer convex reformulation. Numerical results regarding the final annual operating costs of the network demonstrate that the proposed mixed-integer convex model is efficient for selecting and locating D-STATCOMs in distribution networks, with the main advantage that it is applicable to radial and meshed distribution grid configurations. A comparative analysis with respect to metaheuristic optimizers and convex approximations confirms the robustness of the proposed formulation. All numerical validations were conducted in the MATLAB programming environment with our own scripts (in the case of metaheuristics) and the CVX convex disciplined tool via the Gurobi solver. In addition, the exact MINLP model is solved using the GAMS software.

Phase space analysis of the dynamics on a potential energy surface with an entrance channel and two potential wells.

In this paper, we unveil the geometrical template of phase space structures that governs transport in a Hamiltonian system described by a potential energy surface with an entrance/exit channel and two wells separated by an index-1 saddle. For the analysis of the nonlinear dynamics mechanisms, we apply the method of Lagrangian descriptors, a trajectory-based scalar diagnostic tool that is capable of providing a detailed phase space tomography of the interplay between the invariant manifolds of the system. Our analysis reveals that the stable and unstable manifolds of the two families of unstable periodic orbits (UPOs) that exist in the regions of the wells are responsible for controlling access to the potential wells of the trajectories that enter the system through the entrance/exit channel. We demonstrate that the heteroclinic and homoclinic connections that arise in the system between the manifolds of the families of UPOs characterize the branching ratio, a relevant quantity used to measure product distributions in chemical reaction dynamics.

Transport pathways across the West African Monsoon as revealed by Lagrangian Coherent Structures.

The West African Monsoon (WAM) system is the main source of rainfall in the agriculturally based region of the Sahel. Understanding transport across the WAM is of crucial importance due to the strong impact of humidity and dust pathways on local cloud formation. However, the description of this transport is challenging due to its 3D complex nature. Lagrangian Coherent Structures (LCS) simplify transport description across the WAM by providing a geometrical partition of the troposphere into domains. Air parcels within each domain have similar dynamical characteristics. LCS make it possible to achieve an integrated vision of transport pathways across this system. Using this approach we unveil new connections in the WAM system. In particular, we identify transport pathways between the Tropical Easterly Jet (TEJ) and the African Easterly Jet (AEJ). Furthermore, the clockwise circulation associated with the divergent upper part of the Sahara heat low is clearly delimitated. Additionally, we show the presence of mixing regions in the AEJ and the lower part of the TEJ that are linked to pathways to sources of dust and humidity.

[Metabolic control and school performance in children with type 1 diabetes]. / Control metabólico y rendimiento escolar en niños con diabetes tipo 1.

The impact of type 1 diabetes (T1D) on school performance is controversial. OBJECTIVE: To study the relationship between school performance and metabolic control in children with T1D (Ch-T1D), comparing their school grades to general population children (Ch-GP). PATIENTS AND METHOD: Clinical data for 66 Ch-T1D was reviewed, school grades were compared in Ch-T1D with Glycated Haemoglobin (HbA1c) HbA1c < 7.5% and ≥ 7.5%. School marks were also compared between Ch-T1D and Ch-GP from the same level, community and school type (public, private o chartered). Simple linear regression analysis and Mann Whitney test were used to compare groups. A p < 0.05 was considered significant. RESULTS: Ch-T1D were: 13.4 ± 2.9 years old, T1D duration: 5.3 ± 3.2 years, HbA1c was 8.6 ± 1.9% and capillary blood glucose was measured 3.2 ± 1.2 times per day. Grade averages showed no correlation with HbA1c, diabetes duration, hypothyroidism, mental health issues, neither with hypoglycemia or ketoacidosis records. However, primary education Ch-T1D showed lower grades than Ch-GP 5.6 ± 0.7 and 6.0 ± 0.2 (p = 0,0002). School grades correlated with the number of capillary blood glucose readings per day, Pearson correlation coefficient (r) 0.25, 0.41, 0.52 and 0.58 with general grade point average, math, language, and history average respectively (p < 0.05). School non-pass rate was 6.1% in Ch-T1D and 4.8% in Ch-GP (p = 0.65) and school dropout rate was 10.5% in Ch-T1D and 7.7% in Ch-GP (p = 0.47). CONCLUSION: Ch-T1D attending primary school showed lower school grades than Ch-GP, and patients who more frequently checked capillary blood glucose showed better school grades. T1D may have a deleterious impact on school performance.

Control metabólico y rendimiento escolar en niños con diabetes tipo 1 / Metabolic control and school performance in children with type 1 diabetes

El impacto de la diabetes tipo 1 (DM1) en el rendimiento escolar es controversial. Objetivo: Evaluar la relación entre rendimiento escolar y control metabólico en niños con DM1 (N-DM1) y comparar sus resultados con niños de la población general (N-PG). Pacientes y Método: Se revisaron datos clínicos de 66 N-DM1. Se compararon las calificaciones de N-DM1 según Hemoglobina Glicosilada (HbA1c) < 7,5% y ≥ 7,5% con N-PG del mismo nivel, comuna, tipo de colegio (municipal, particular subvencionado y particular pagado) y localidad. Para la comparación de los grupos se utilizó la regresión lineal simple y el test de suma de los rangos de Wilcoxon (Mann y Whitney) previa comprobación de incumplimiento de normalidad con el test de Shapiro-Wilk según el caso. Se consideró un valor de p < 0,05 como estadísticamente significativo con una confiabilidad del 95%. Resultados: La edad fue 13,4 ± 2,9 años, tiempo de evolución DM1 5,3 ± 3,2 años, HbA1c 8,6 ± 1,9% y controles de glicemia capilar 3,2 ± 1,2 veces por día. Las calificaciones no mostraron correlación con HbA1c, duración de DM1, hipotiroidismo, problemas de salud mental, antecedentes de hipoglicemia ni de cetoacidosis. N-DM1 de educación básica mostraron calificaciones inferiores a N-PG del mismo nivel 5,6 ± 0,7 vs 6,0 ± 0,2 (p = 0,0002). Las calificaciones se correlacionaron con el número de controles diarios de glicemia capilar, coeficiente de correlación de Pearson (r) de 0,25, 0,41, 0,52 y 0,58 con el promedio general, matemática, lenguaje e historia respectivamente (p < 0,05). Un 6,1% de N-DM1 y 4,8% de N-PG no fue promovido de curso (p = 0,65). La deserción escolar fue 10,5% en N-DM1 y 7,7% en N-PG (p = 0,47). Conclusión: N-DM1que cursaban educación básica tuvieron calificaciones inferiores a N-PG y los pacientes que controlaban su glicemia capilar con mayor frecuencia mostraron mejores calificaciones. La DM1 puede tener un impacto deletéreo en el rendimiento escolar.

The impact of type 1 diabetes (T1D) on school performance is controversial. Objective: To study the relationship between school performance and metabolic control in children with T1D (Ch-T1D), comparing their school grades to general population children (Ch-GP). Patients and Method: Clinical data for 66 Ch-T1D was reviewed, school grades were compared in Ch-T1D with Glycated Haemoglobin (HbA1c) HbA1c < 7.5% and ≥ 7.5%. School marks were also compared between Ch-T1D and Ch-GP from the same level, community and school type (public, private o chartered). Simple linear regression analysis and Mann Whitney test were used to compare groups. A p < 0.05 was considered significant. Results: Ch-T1D were: 13.4 ± 2.9 years old, T1D duration: 5.3 ± 3.2 years, HbA1c was 8.6 ± 1.9% and capillary blood glucose was measured 3.2 ± 1.2 times per day. Grade averages showed no correlation with HbA1c, diabetes duration, hypothyroidism, mental health issues, neither with hypoglycemia or ketoacidosis records. However, primary education Ch-T1D showed lower grades than Ch-GP 5.6 ± 0.7 and 6.0 ± 0.2 (p = 0,0002). School grades correlated with the number of capillary blood glucose readings per day, Pearson correlation coefficient (r) 0.25, 0.41, 0.52 and 0.58 with general grade point average, math, language, and history average respectively (p < 0.05). School non-pass rate was 6.1% in Ch-T1D and 4.8% in Ch-GP (p = 0.65) and school dropout rate was 10.5% in Ch-T1D and 7.7% in Ch-GP (p = 0.47). Conclusion: Ch-T1D attending primary school showed lower school grades than Ch-GP, and patients who more frequently checked capillary blood glucose showed better school grades. T1D may have a deleterious impact on school performance.

Evaluation of postharvest-processed oysters by using PCR-based most-probable-number enumeration of Vibrio vulnificus bacteria.

Postharvest processing (PHP) is used to reduce levels of Vibrio vulnificus in oysters, but process validation is labor-intensive and expensive. Therefore, quantitative PCR was evaluated as a rapid confirmation method for most-probable-number enumeration (QPCR-MPN) of V. vulnificus bacteria in PHP oysters. QPCR-MPN showed excellent correlation (R(2) = 0.97) with standard MPN and increased assay sensitivity and efficiency.

Domain-size distribution in a Poisson-Voronoi nucleation and growth transformation.

We present an analytical result for the evolution of the domain-size distribution during the growth of simultaneously nucleated domains. The final stage of this transformation is the well-known Poisson-Voronoi tessellation. The method can be easily extended to the calculation of the probability distribution of any other geometric characteristic. As far as we know, it is the first time that an exact result is given for this classic system.

Tema especial: "El Impedido" / Special theme: \"The Handicapped\"

El objetivo del trabajo fué identificar las causas de incapacidad que inciden en la población infantil, tomando en cuenta a la persona como un ente bio-psico-social. Se dividió el tema en 6 partes que incluyeron las causas y prevención de la incapacidad, organización y observación de los servicios de rehabilitación, recursos humanos, medios de comunicación social y el impedido, y se dieron conclusiones por cada aspecto tratado