In Mexico and many parts of the world, land cargo transport units (UTTC) operate at high speeds, causing accidents, increased fuel costs, and high levels of polluting emissions in the atmosphere. The speed in road driving, by the carriers, has been a factor little studied; however, it causes serious damage. This problem is reflected in accidents, road damage, low efficiency in the life of the engine and tires, low fuel efficiency, and high polluting emissions, among others. The official Mexican standard NOM-012-SCT-2-2017 on the weight and maximum dimensions with which motor transport vehicles can circulate, which travel through the general communication routes of the federal jurisdiction, establishes the speed limit at the one to be driven by an operator. Because of the new reality, the uses and customs of truck operators have been affected, mainly in their operating expenses. In this work, a mathematical model is presented with which the optimum driving speed of a UTTC is obtained. The speed is obtained employing the equality between the forces required to move the motor unit and the force that the tractor has available. The required forces considered are the force on the slope, the aerodynamic force, and the friction force, and the force available was considered the engine torque. This mathematical method was tested in seven routes in Mexico, obtaining significant savings of fuel above 10%. However, the best performance route possesses 65% flat terrain and 35% hillocks without mountainous terrain, regular type of highway, and a load of 20,000 kg, where the savings increase up to 16.44%.

Objetivo: determinar la relación de los elementos de la dinámica familiar como comunicación y cohesión con las conductas de riesgo del adolescente y la de sus padres. Materiales y métodos: estudio transversal descriptivo correlacional en una muestra no probabilística por conveniencia de 50 adolescentes con sus respectivos padres, pertenecientes a una telesecundaria de la ciudad de Cosoleacaque, Veracruz durante los meses de octubre y noviembre de 2014. Previo consentimiento informado se aplicó una cédula de datos sociodemográficos y el test de la Organización Panamericana de la Salud "Cómo es Tu familia" y "Cómo es Su Familia", que midió la comunicación padre-hijo y las conductas de riesgo, y la Faces III de Olson que valoró la cohesión padre-hijo. El análisis de la prueba Chi-Cuadrada y coeficiente de Spearman se realizó en el Paquete Estadístico para las Ciencias Sociales. Resultados: la media de edad de los adolescentes fue de 13.3 ± 1.23 años. La cohesión y comunicación de los padres no se asocia con la conducta de riesgo del adolescente (p=0.218>0.05 y p=.981>0.05, respectivamente). La conducta de riesgo del padre sí se asocia con la conducta de riesgo de los adolescentes (p=0.002 <0.05). Conclusión: la dinámica familiar no se asocia con las conductas de riesgo del adolescente, pero sí se asocia con la conducta de riesgo del padre, lo que es importante para el profesional de enfermería en el campo de la promoción de la salud al brindar estrategias familiares que impacten en la conducta de los padres y en su bienestar integral. Palabras clave Asunción de riesgos, relaciones familiares, comunicación, adolescente, padres (Fuente: DeCS, BIREME). * Article linked to research: La dinámica familiar del adolescente con padres alcohólicos.

The peak demand or demand limit control is an important part of the actions that industries carry out to optimize their energy consumption and reduce the costs related to their electricity billing. Prioritized switching of multiple appliances is often needed in order to reduce demand and energy consumption during peak load periods. The present article describes a peak load limitation algorithm that estimates the optimal disconnection time for one or more electrical loads before the electric demand exceeds a preset limit. This algorithm uses parametric and variable load factors that vary dynamically depending on what loads are present at a given time. For its validation, a software-in-the-loop testbed was designed and developed, in which multiple electrical loads were simulated via LabVIEW software and connected to a PLC controller emulated through CODESYS software. In this environment, several test configurations were executed and evaluated to study the influence of variables such as the nominal power and the disconnection priority of loads in the algorithm output. The results showed that the control algorithm is effective for peak load limitation, the maximum demand value reached during simulations tests did not exceed the preset demand limit at any time interval. The performance of the algorithm could be improved when prioritizing the shutdown of loads with higher nominal power or when increasing the anticipation time used for the disconnection of the controllable loads.INDEX TERMS Demand response, demand side management, load levelling, peak shaving, smart grid.