190 research outputs found
The Complexity Of The NP-Class
This paper presents a novel and straight formulation, and gives a complete
insight towards the understanding of the complexity of the problems of the so
called NP-Class. In particular, this paper focuses in the Searching of the
Optimal Geometrical Structures and the Travelling Salesman Problems. The main
results are the polynomial reduction procedure and the solution to the Noted
Conjecture of the NP-Class
Preliminary design of a radiator shading device for a lunar outpost
The National Aeronautics and Space Administration is designing a thermal control system for an outpost to be placed permanently on the Moon. One of the functions of the thermal control system is to reject waste heat, which can be accomplished through a radiator. At the lunar equator and during the lunar midday, an unshaded radiator absorbs more heat than it rejects. This problem can be solved by using a shading device to reduce radiation incident on the radiator. The design team was asked to develop concepts for reducing the radiation incident on the radiator and for deploying the radiator and shade system for a 10 kW and a 25 kW heat rejection system. The design team was also asked to develop the best concepts into preliminary design. From the several alternatives developed by the design team, the best one was selected using a decision matrix. Preliminary design of the best concept include support structure, stress analyses, and thermal performance. In addition, the team developed ideas for removing lunar dust from the shading device. The final design solution consisted of a winged radiator shading system with a rail support structure and a scissors mechanism for deployment. The total radiator area required was calculated to be 389 sq m for the 10 kW heat rejection system and 973 sq m for the 25 kW heat rejection system
Caries Dental asociada al índice de higiene oral simplificado en niños de 6 a 9 años de la Institución Educativa Privada San Antonio de Padua distrito Villa El Salvador - 2017
RESUMEN
Objetivo: Se realizó el estudio con el objetivo evaluar la asociación entre la presencia de caries dental y el índice de higiene oral simplificado en niños de 6 a 9 años de la I.E.P “San Antonio de Padua” Villa el salvador 2017. Materiales y Método: Se realizó un estudio de tipo descriptivo. La muestra estuvo formada por 100 niños de la I.E.P “San Antonio de Padua”, los cuales fueron evaluados mediante una ficha de recolección de datos. Los datos fueron recolectados caso a caso y se utilizó un equipo de diagnóstico, baja lenguas, guantes de látex, linterna, gasas, lapiceros, portaminas y fichas de recolección de datos. Resultados: Durante la investigación se obtuvo los siguientes resultados, una relación altamente significativa entre la caries y el instrumento utilizado, el 50% de los niños tenían caries y regular higiene, 28% presentaban buena higiene oral, solo 6 % presentaban mala higiene oral; en prevalencia de caries 93% presentaron caries y 7% ausencia de caries; el valor de piezas dentarias con caries fue mayor al de piezas y menor valor se hallaron perdidas y obturadas, mostrándose 50 piezas cariadas en niños de 9 años; se halló relación entre instrumento utilizado y la edad, los niños de 8 años tuvieron un porcentaje regular en lo que compete a la a salud bucal 68.8%, niños de 9 años tuvieron buena higiene oral 50.0%, los de 7 años tuvieron mala higiene oral 8.3%.
El resultado obtenido fue altamente significativo donde chi2 resulto una proporción igual a IHO (P=0.00) lo cual indica una alta relación entre la caries y el instrumento utilizado en la investigación.
Conclusiones: Se concluyó que hubo una asociación significativamente alta entre la caries y el instrumento utilizado.
Palabras Claves: IHO, Caries dental, Salud bucal.Tesi
Diseño de un sistema de seguridad y salud en el trabajo basado en la ISO 45001:2018 para minimizar accidentes e incidentes en la empresa Lácteos Huacariz S. A. C. Cajamarca, 2020
El objetivo general del presente proyecto de tesis fue diseñar un sistema de seguridad y salud en el trabajo basado en la ISO 45001:2018 para minimizar accidentes e incidentes en la empresa Lácteos Huacariz S.A.C, Cajamarca 2020; para lo cual se logró identificar la problemática, encontrando que tienen un cumplimiento de 10%; 5%; 50%; 10%; 25%; 40%; 25% en las dimensiones de contexto de la organización; liderazgo y participación de los trabajadores; planificación; apoyo; operación; evaluación del desempeño; y la mejor/ acción para le mejora continua respectivamente. Para solucionar, se diseñó el sistema basado en la ISO 45001:2018, la cual proporciona a la empresa y otras partes interesadas afectadas una guía eficaz y útil para mejorar la seguridad de los trabajadores, mediante un marco fácil de usar, procedimientos y manuales de trabajo con lo que se obtuvo un cumplimiento del 100%. Teniendo como efecto reducir la frecuencia de: i) accidentes, ii) incidentes y iii) el porcentaje de días de trabajo perdido
Characterization of volatile compounds of cooked wild Iberian red deer meat extracted with solid phase microextraction and analysed by capillary gas chromatography - mass spectrometry
Wild Iberian red deer meat demand and interest are increasing and, therefore, an in-depth characterization of meat quality is needed to meet consumer demands. The objective of the present work was to assess, for the first time, the volatile profile of cooked wild sport-hunted Iberian red deer meat. Twenty-three loin samples from male red deer (Cervus elaphus hispanicus) were cooked and the volatile profile was analysed using solid phase microextraction, followed by capillary gas chromatography-mass spectrometry. Fifty-five volatile compounds were found. The major ones in number and relative abundance were aldehydes (84%), followed by alcohols (11%), hydrocarbons (2.4%), ketones (1.7%), furans (0.34%) and sulphur compounds (0.18%). Hexadecanal was the major compound and other long-chain compounds such as (E)-2-tetradecen-1-ol or 2-pentadecanone were also reported in considerable abundance. Several compounds related to grass-based diets were identified (2,3-octanedione, hexadecane or 1-pentadecanol). Odour impact ratio of volatile compounds was calculated and dimethyl trisulphide, (E,E)-2,4-decadienal, decanal and dodecanal were the most odorant compounds affecting the flavour of the cooked deer meat.Gobierno Vasco | Ref. IT944-16Ministerio de Economía y Competitividad | Ref. RTC-2016-5327-2Axencia Galega de Innovación | Ref. IN607A2019/01CYTED | Ref. 119RT056
Design and Implementation of a Demonstrative Palletizer Robot with Navigation for Educational Purposes
Nowadays, many kinds of robots are used in industries to help in manufacturing or placing objects. However, teaching young people and children about robot design and work can be difficult, turning this into a complicated area for them. This chapter provides a detailed description of the design and implementation of a robotic arm mounted on a mobile robot using the LEGO Mindstorms NXT kit® and the starter kit DaNI 2.0, designed by National Instruments®. The mobile palletizer robot takes a box from place A and navigates in the indoor environment until it reaches a predefined place B. The characterization of the robotic arm is based on a parallel structure considering that the end-effector has only two points to hold the object; the gripper is also built using LEGO®. The robot performs the path computed using an A-star algorithm; moreover, actions like moving up and down, opening and closing the gripper and picking up the box and putting it down are executed by the robotic arm using the central unit of the NXT kit. Each stage of the robot design and implementation is explained in detail using diagrams and 3D graphical views with the aim of illustrating the implementation step by step for educational purposes (mainly for young people or children)
Capacidad de carga en senderos turísticos del centro de cultura para la conservación Piedra Herrada, México.
El turismo de naturaleza se plantea como una aspiración que pretende el aprovechamiento recreativo de los recursos y la justa distribución de los beneficios que genera. No obstante en la actualidad, numerosas iniciativas difieren poco de la valorización económica del patrimonio y su uso intensivo. Por ello, es necesario dar continuidad a los estudios ambientales del turismo, que identifican sus implicaciones físicas y plantean medidas de mitigación para el adecuado desarrollo de la actividad. El trabajo tuvo como principal objetivo, determinar la capacidad de carga en los senderos turísticos del Centro de Cultura para la Conservación Piedra Herrada, con base al método propuesto por Cifuentes (1992; et. al, 2009), para el cálculo de las capacidades de carga física, real, de manejo y efectiva (turística) del lugar de estudio.El turismo de naturaleza se plantea como una aspiración que pretende el aprovechamiento recreativo de los recursos y la justa distribución de los beneficios que genera. No obstante en la actualidad, numerosas iniciativas difieren poco de la valorización económica del patrimonio y su uso intensivo. Por ello, es necesario dar continuidad a los estudios ambientales del turismo, que identifican sus implicaciones físicas y plantean medidas de mitigación para el adecuado desarrollo de la actividad. El trabajo tuvo como principal objetivo, determinar la capacidad de carga en los senderos turísticos del Centro de Cultura para la Conservación Piedra Herrada, con base al método propuesto por Cifuentes (1992; et. al, 2009), para el cálculo de las capacidades de carga física, real, de manejo y efectiva (turística) del lugar de estudio
The origin of the parrotfish species Scarus compressus in the Tropical Eastern Pacific: region-wide hybridization between ancient species pairs
BACKGROUND: In the Tropical Eastern Pacific (TEP), four species of parrotfishes with complex phylogeographic histories co-occur in sympatry on rocky reefs from Baja California to Ecuador: Scarus compressus, S. ghobban, S. perrico, and S. rubroviolaceus. The most divergent, S. perrico, separated from a Central Indo-Pacific ancestor in the late Miocene (6.6 Ma). We tested the hypothesis that S. compressus was the result of ongoing hybridization among the other three species by sequencing four nuclear markers and a mitochondrial locus in samples spanning 2/3 of the latitudinal extent of the TEP.
RESULTS: A Structure model indicated that K = 3 fit the nuclear data and that S. compressus individuals had admixed genomes. Our data could correctly detect and assign pure adults and F1 hybrids with > 0.90 probability, and correct assignment of F2s was also high in some cases. NewHybrids models revealed that 89.8% (n = 59) of the S. compressus samples were F1 hybrids between either S. perrico × S. ghobban or S. perrico × S. rubroviolaceus. Similarly, the most recently diverged S. ghobban and S. rubroviolaceus were hybridizing in small numbers, with half of the admixed individuals assigned to F1 hybrids and the remainder likely > F1 hybrids. We observed strong mito-nuclear discordance in all hybrid pairs. Migrate models favored gene flow between S. perrico and S. ghobban, but not other species pairs.
CONCLUSIONS: Mating between divergent species is giving rise to a region-wide, multispecies hybrid complex, characterized by a high frequency of parental and F1 genotypes but a low frequency of > F1 hybrids. Trimodal structure, and evidence for fertility of both male and female F1 hybrids, suggest that fitness declines sharply in later generation hybrids. In contrast, the hybrid population of the two more recently diverged species had similar frequencies of F1 and > F1 hybrids, suggesting accelerating post-mating incompatibility with time. Mitochondrial genotypes in hybrids suggest that indiscriminate mating by male S. perrico is driving pre-zygotic breakdown, which may reflect isolation of this endemic species for millions of years resulting in weak selection for conspecific mate recognition. Despite overlapping habitat use and high rates of hybridization, species boundaries are maintained by a combination of pre- and post-mating processes in this complex
Clinical utility of two-dimensional Doppler echocardiographic techniques for estimating pulmonary to systemic blood flow ratios in children with left to right shunting atrial septal defect, ventricular septal defect or patent ductus arteriosus
Range gated two-dimensional Doppler echocardiographic methods were evaluated for quantifying pulmonary (QP) to systemic (QS) blood flow ratios. Twenty-one patients were studied, 4 with patent ductus arteriosus, 6 with atrial septal defect and 11 with ventricular septal defect. The Doppler pulmonary to systemic flow (QP:QS) estimation method involved calculating volume flow (liters/min) at a variety of intracardiac sites by using imaging information for flow area and Doppler outputs to calculate mean flow velocity as a function of time. Area volume flows were combined to yield QP:QS ratios. The sites sampled were main pulmonary artery, ascending aorta, mitral valve orifice and subpulmonary right ventricular outflow tract. The overall correlation between Doppler QP:QS estimates and those obtained at cardiac catheterization (n = 18) or radionuclide angiography (n = 3) was r = 0.85 (standard error of the estimate = 0.48:1). These preliminary results suggest that clinical application of this Doppler echocardiographic method should allow noninvasive estimation of the magnitude of cardiac shunts
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