Motivación y desempeño laboral de los vigilantes de la Municipalidad Provincial del Santa, Chimbote - 2021

El propósito del presente proyecto de investigación fue describir la asociación que existe entre la motivación y el desempeño laboral la Municipalidad Provincial del Santa. El tipo de investigación fue de tipo descriptivo correlacional, con diseño no experimental de corte transversal, con enfoque cuantitativo. La población la constituyeron 287 vigilantes, y como muestra se tuvo a 83 vigilantes, utilizándose el método probabilístico. La técnica fue la encuesta y el instrumento fue el cuestionario. El resultado obtenido es que existe una relación significativa entre las variables de estudio correspondiente a los vigilantes de la Municipalidad Provincial del Santa, con un nivel de significancia de 0.000, menor al 5% (pTesi

Pátinas protectoras del cobre en esculturas y piezas ornamentales del patrimonio cultural

El cobre y sus aleaciones han sido materiales ampliamente utilizados para la construcción de esculturas y piezas ornamentales del patrimonio cultural por su capacidad de desarrollar pátinas protectoras en condiciones atmosféricas oxidantes que corresponden a un óxido cuproso color marrón y que posteriormente se oxida a óxido cúprico. Además, de acuerdo a las características ambientales, pueden formarse otros compuestos tales como sulfatos, nitratos, carbonatos, cloruros, etc. originando la denominada “pátina verde”. Debido a la importancia de estas cubiertas protectoras en la preservación del patrimonio cultural se analizan sucesivamente la composición química, las propiedades termodinámicas y las técnicas de producción de diferentes pátinas naturales y artificiales. Finalmente se discuten distintos procedimientos para limpieza y tratamiento químico de la superficie metálica.Tópico 2: Conservación y restauración de pinturas, cueros, textiles y metales

Atmospheric and microbiological deterioration of the church of Veracruz in Medellin

La iglesia de la Veracruz es uno de los edificios más representativos del patrimonio cultural de la ciudad de Medellín. Su frontis está constituido por peridotita, roca ultramáfica con un contenido cercano a 90% de minerales de hierro y magnesio, del tipo de los olivinos y los piroxenos. En este trabajo se presentan los estudios sobre las causas del biodeterioro del material de la fachada de la iglesia y el efecto sobre el mismo del microclima de la zona, mediante el uso de técnicas que abarcan la evaluación de contaminantes ambientales, aislamiento e identificación de microorganismos, observaciones por microscopía óptica y electrónica de barrido, y análisis de superficies por energía de dispersión de rayos X, difracción de rayos X y espectroscopia de infrarrojo por transformadas de Fourier. Se analiza la incidencia de los factores atmosféricos y biológicos y se formulan los posibles mecanismos de deterioro de la peridotita.The case history chosen for this study is the church of Veracruz, the most representative temple of the cultural heritage of the city of Medellin, Colombia. Its front was built with peridotite, an ultramafic rock containing more than 90% of iron and magnesium minerals, such as olivine and pyroxene. The possible causes of biodeterioration are studied by using microbiological techniques of isolation and culture, complemented with optical and electron scanning microscopy observations. The impact of atmospheric factors on the structural material is studied by assessing the characteristics and amounts of atmospheric pollutants. Three different surface analysis techniques were used: energy dispersive X-ray analysis, X-ray diffraction and Fourier transform infrared spectroscopy.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Pulvimetalurgia: Proceso sostenible para la fabricación de carburos cementados en Colombia

This paper presents the opportunity to promote the Colombian industry towards the development of new high performance materials manufactured by powder metallurgy(PM) as an alternative to the conventional manufacturing processes, generating new needs for the national industry. The objective of this work is describe the manufacturingprocesses of composite materials, type CERMET, formed by a CERAMIC phase, which is tungsten carbide (WC), and a METAL phase which is cobalt (Co). Additionally, analyzeat microstructural level the manufactured materials using vacuum sintering process. The designed alloy was a mixture of 88% WC and 12% Co according to ISO K40 standard. The process involved the control of precursor materials, found in powder form, followed by mixing and milling steps, and finally compaction and sintering. The microstructures and chemical compositions obtained by scanning electron microscopy (SEM-EDS) were studied inorder to evaluate the mechanical behavior of the CerMet;for that, microhardness tests were performed reaching values of 1289HV0.5, which are related with the low porosity levels such as A02, B00, C00, and average grain size of 1.14 μm. These results indicate that is possible to manufacture wear resistance high performance materials in the country. It highlights the relevance of enhancing the synergy between government entities such as SENAColciencias -Universidad Nacional to create applied research in the country.En este trabajo se da a conocer la oportunidad de impulsar la industria colombiana hacia el desarrollo de nuevos materiales de altas prestaciones fabricados por vías pulvimetalúrgicas (PM) como alternativa a los procesos de fabricación convencional, generando nuevas necesidades para la industria nacional. El objetivo es describir el proceso de fabricación de materiales compuestos, tipo CERMET, formado por una fase CERámica la cual es carburo de wolframio (WC) y una fase METálica que es el cobalto (Co) y analizar los cambios a nivel microestructural de los materiales fabricados utilizando el proceso de sinterización en vacío. La aleación diseñada fue una mezcla de 88%WC y 12%Co de designación ISO K40; el proceso involucró el control de los materiales precursores que se encuentran en forma de polvo, seguido de los procesos de mezcla y molienda, para luego realizar la compactación y sinterización. Se estudian las microestructuras y composiciones químicas obtenidas mediante microscopía electrónica de barrido (SEM-EDS); con el fin de evaluar el comportamiento mecánico del CERMET fabricado, se realizaron ensayos de microdureza alcanzando valores de 1289HV0.5 que se correlaciona con los bajos niveles de porosidad obtenidos de tipo A02, B00, C00, y tamaño de grano medio de 1,14 μm. Estos resultados indican que es posible fabricar materiales con altas prestaciones de resistencia al desgaste en el país. Se resalta la importancia que tiene potenciar la sinergia entre entidades gubernamentales como SENA-Colciencias –Universidad Nacional para generar investigación aplicada en el país

Estudio de la resistencia a la tracción de depósitos de soldadura de la aleación AA2024-T3

En el presente artículo, se realiza un estudio de la resistencia a la tracción de diferentes depósitos de soldadura sobre láminas de la aleación de aluminio AA2024-T3 AlClad. La soldabilidad de la aleación, bajo procesos de arco, se considera limitada por su sensibilidad al agrietamiento en caliente y, por ello, se encuentra ampliamente estudiada en procesos de estado sólido o láser, en los que la afectación térmica es menor. La investigación tiene como objetivo estudiar el comportamiento mecánico de dicho aluminio al soldarlo con tecnología local. Para la experimentación, se realizaron depósitos con combinaciones de electrodo no consumible punto violeta, electrodo no consumible punto verde, metal de aporte ER4043 y sin metal de aporte (soldadura autógena). Los ensayos mecánicos estuvieron bajo el estándar ASTM E8 y bajo las recomendaciones del estándar AWS D1.2. Adicionalmente, se realizó el respectivo estudio de las superficies de fractura de cada uno de los depósitos. Entre los resultados, se destaca la notable reducción tanto de resistencia mecánica como de ductilidad, lo cual se debió a la alta presencia de porosidad, que desencadenó grietas de diversos tamaños, ligados, también, a una fragilización por hidrógeno y por presencia de partículas de segunda fase en los límites de grano

Solid-State and Super Solidus Liquid Phase Sintering of 4340 Steel SLM Powders Shaped by Fused Filament Fabrication

4340 steel powders were processed with an additive manufacturing process using the FFF (Fused Filament Fabrication) technique. A composite filament was developed to print samples and study the effect of the bed and nozzle temperatures on its physical and microstructural properties. The printed samples were debinded and sintered by: Solid State (SS) at 1300 °C or SLPS (Supersolidus Liquid Phase Sintering) at 1420 °C. Metallography and scanning electron microscopy (SEM) identified the microstructure and phases. The hardness of the sintered samples was measured with the Vickers method. The SLPS process contributes to better densification and volume contraction; however, it promotes geometrical distortion of the samples compared to the SS samples. The microstructure of the sintered samples consists of ferrite situated in the original austenite grain and bainite. The sintering mechanism significantly influenced the hardness of the samples. Finally, a part was designed, printed, debinded, and sintered with the aim of studying the maximum inclination angle, the minimum vertical and horizontal holes, and the minimum vertical layer thickness, which can be obtained through the whole process

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat