ABSTRACT Brazil has the highest incidence of atmospheric discharges, on average of 77.8 million hitting the country yearly. Companies providing post-harvest services have a high monetary value concentrated in their predominantly metallic structures. Atmospheric discharge protection systems (ADPS) are used in this context to protect the facilities and people, composed of several elements that require visual inspection with a certain periodicity, an activity framed as working at height. This research aimed to establish a methodology for employing a Remotely Piloted Aircraft System (RPAS) in the visual analysis of the operational condition of external atmospheric discharge protection systems components located in grain storage structures to collect information during the preliminary risk analysis and planning of activities at height. A survey of the current literature related to the subject was carried out, in addition to the norms, inspection agencies, and operational prerequisites of this type of equipment in the national territory. Finally, a method was created and validated based on the inspection checklist with the main points for checking, which generates a score that represents the urgency level of intervention, applied in a unit located in western Paraná, Brazil, on 11/28/2022. This procedure eliminated the risk of workers falling during the planning and inspection stage of the structures, which helped the qualified professional to issue the technical inspection report more quickly. The disadvantage is related to the dependence on favorable weather conditions. discharges 778 77 8 77. yearly postharvest post harvest ADPS (ADPS people periodicity height RPAS (RPAS out norms agencies territory Finally checking intervention Paraná 11282022 11 28 2022 11/28/2022 quickly conditions 7 1128202 1 2 202 11/28/202 112820 20 11/28/20 11282 11/28/2 1128 11/28/ 112 11/28 11/2 11/

RESUMO O Brasil é o país com a maior incidência de descargas atmosféricas, em média 77,8 milhões atingem o país todos os anos. As empresas prestadoras de serviços pós-colheita possuem um elevado valor monetário concentrado em suas estruturas, que predominantemente são metálicas. Os sistemas de proteção contra descargas atmosféricas (SPDA) são utilizados neste contexto para realizar a proteção das instalações e pessoas, os quais são compostos por vários elementos que necessitam de inspeção visual com determinada periodicidade, atividade enquadrada como trabalho em altura. Esta pesquisa tem como objetivo estabelecer uma metodologia para o emprego de Remotely Piloted Aircraft System (RPAS) na análise visual das condições operacionais dos componentes de um sistema de proteção contra descargas atmosféricas externo, localizados em estruturas de armazenamento de grãos para coletar informações durante a análise preliminar de riscos e planejamento das atividades em altura. Realizou-se um levantamento da atual literatura relacionada ao assunto, além das normas, órgãos fiscalizadores e pré-requisitos operacionais deste tipo de equipamento em território nacional. Por fim, foi criado e validado um método com base no checklist de inspeção com os principais pontos para conferência, que gera uma pontuação que representa o nível de urgência de intervenção, aplicado em uma unidade localizada no oeste do Paraná, Brasil, em 28/11/2022. Este procedimento eliminou o risco de queda do trabalhador na etapa de planejamento e inspeção das estruturas, o que auxiliou o profissional habilitado a emitir o laudo técnico de vistoria com maior agilidade. A desvantagem relaciona-se à dependência das condições climáticas favoráveis. 778 77 8 77, anos póscolheita pós colheita metálicas SPDA (SPDA pessoas periodicidade altura RPAS (RPAS externo Realizouse Realizou se assunto normas prérequisitos pré requisitos nacional fim conferência intervenção Paraná 28112022 28 11 2022 28/11/2022 agilidade relacionase relaciona favoráveis 7 2811202 2 1 202 28/11/202 281120 20 28/11/20 28112 28/11/2 2811 28/11/ 281 28/11 28/1 28/

The article considers the periodic table of chemical elements, and that it is a graphic representation of the periodic law, although more than 150 years have passed since the opening of the periodic law, there is no precise formulation of the mathematical formula of this law. The formulas presented in the article are difficult to summarize the periodic law, they are difficult to understand, so the goal of the study is to derive a simplified mathematical equation and formulate a periodic law based on an analysis of the literature and its data on periodic changes in the properties of chemical elements and their compounds. The object of study is the 32-cell version of the periodic table, which does not break the table into parts with the introduction of lanthanides and actinoids into the lower part of the table. It best shows how periods are similar and the main physical and chemical properties of elements in groups, as well as how often they happen, when subscripts (lanthanides and actinides) are put together in a single table that matches the natural ordinal number of where these elements are in periods. The definitions of periodic law are compared, and the work of research scientists is analyzed. This article provides suggestions on how to fill such inconsistencies. Nowadays, there are more than 700 variants of the graphic construction of Periodic Table; the most recognized is IUPAC.

ABSTRACT Climate variability is of global interest due to its socioeconomic and environmental effects on the world’s population. In Colombia, temperature changes affect food security, especially for the most vulnerable people in the Caribbean region. We analyzed monthly air temperature in northeastern Colombia (Cesar, La Guajira, and Magdalena departments). We reconstructed time series with missing data using nonlinear principal component analysis. Subsequently, temporal variability, associations with events of climatic variability, and temporal trends were evaluated. Periodicity analyses indicate the dominance of annual variability, although statistically significant associations with periods between 3 and 7 years show the influence of El Niño-Southern Oscillation (ENSO) events. The Spearman correlation coefficient with N = 360 and 95% significance shows a better association with the Multivariate ENSO Index (rsp mean = 0.38) and the Southern Oscillation Index (rsp mean = -0.32). The multi-year monthly analysis shows positive trends, with maximum values between March (1.04 ºC month-1), and June (1.07 ºC month-1) in the valley of the Cesar department, and a minimum in March, at the northernmost La Guajira (0.2 ºC month-1).

RESUMEN La variabilidad climática es de interés global debido a sus efectos socioeconómicos y ambientales sobre la población mundial. En Colombia, los cambios de temperatura afectan la seguridad alimentaria, especialmente para la población más vulnerable de la región Caribe. Analizamos la temperatura mensual del aire en la región nororiental colombiana (departamentos de Cesar, La Guajira y Magdalena). Se reconstruyeron series temporales con datos faltantes utilizando análisis de componentes principales no lineales. Posteriormente se evaluaron la variabilidad temporal, las asociaciones con eventos de variabilidad climática y las tendencias temporales. Los análisis de periodicidad indican el predominio de la variabilidad anual, aunque las asociaciones estadísticamente significativas con periodos de 3 a 7 años muestran la influencia de los eventos de El Niño-Oscilación del Sur (ENSO, por su sigla en inglés). El coeficiente de correlación de Spearman con N = 360 y una significancia de 95% muestra una mejor asociación con el Índice Multivariado de ENSO (rsp medio = 0.38) y el Índice de la Oscilación del Sur (rsp medio = -0.32). El análisis multianual mensual muestra tendencias positivas, con valores máximos entre marzo (1.04 ºC mes-1) y junio (1.07 ºC mes-1) en el valle del departamento de Cesar, y un mínimo en marzo, en el extremo norte de La Guajira (0.2 ºC mes-1).

Abstract: The purpose of this article is to analyze the effect of workers’ remittances on the Gross Domestic Product (GDP) and the trade deficit in Honduras. The article was conducted under a quantitative approach, using time series data with annual periodicity from 1990 to 2019 extracted from the Central Bank of Honduras (BCH) and the World Bank (WB). A vector autoregressive model (VAR) is established. The results are presented using impulse response function figures (IRF) and Granger causality table of the VAR model, which reveal a positive response of GDP and a negative response of the trade deficit in the short and medium term to the shock caused by the inflow of workers’ remittances. Remittances were also found to be predictive of GDP variability at the 0.1 significance level and of the trade deficit at the 0.05 significance level.

Resumen: Este artículo tiene como propósito analizar el efecto de las remesas de los trabajadores sobre el Producto Interno Bruto (PIB) y el déficit comercial en Honduras. El artículo se realizó bajo un enfoque cuantitativo, con datos de series temporales con periodicidad anual de 1990 a 2019 extraídos del Banco Central de Honduras (BCH) y el Banco Mundial (BM). Se establece un modelo del tipo vectores autorregresivos (VAR). Los resultados se presentan mediante figuras de función impulso respuesta (IRF) y tabla de causalidad de Granger del modelo VAR, los cuales revelan una respuesta positiva del PIB y negativa del déficit comercial en el corto y mediano plazo ante el choque provocado por el ingreso de las remesas de los trabajadores. También se encontró que las remesas son predictoras de la variabilidad del PIB al 0,1 de nivel de significancia y del déficit comercial a 0,05 de significancia. Clasificación JEL: C32, E23, F24.

Résumé: Le but de cet article est d’analyser l’effet des envois de fonds des travailleurs émigrés sur le produit intérieur brut (PIB) et le déficit commercial du Honduras. L’article a été réalisé selon une approche quantitative, avec des données de séries chronologiques à fréquence annuelle de 1990 à 2019 extraites de la Banque centrale du Honduras (BCH) et de la Banque mondiale (BM). Un modèle vectoriel de type autorégressif (VAR) est établi. Les résultats sont présentés à l’aide des chiffres de la fonction de réponse impulsionnelle (IRF) et du tableau de causalité de Granger du modèle VAR, qui révèlent une réponse positive du PIB et une réponse négative du déficit commercial à court et moyen terme au choc provoqué par l’entrée. des envois de fonds des travailleurs. Il a également été constaté que les envois de fonds sont des prédicteurs de la variabilité du PIB au niveau de signification de 0,1 et du déficit commercial au niveau de signification de 0,05.

Resumen La sardina crinuda azul (Opisthonema bulleri) es parte de los desembarques comerciales de peces pelágicos menores del sur del Golfo de California; la pesquería está certificada como sostenible por Marine Stewardship Council. Los parámetros de crecimiento de esta especie son de gran interés en la evaluación y manejo de la pesquería del complejo Opisthonema. En este estudio, se generó un conjunto de datos de edad a la talla de 367 lecturas de otolitos de los años 2005 y 2015 para completar los meses del año calendario con información continua e inferir la periodicidad de formación de la marca de crecimiento. Se utilizó un enfoque de selección multimodelo en cinco submodelos especiales del modelo de Schnute generalizado, incluido uno equivalente al modelo de von Bertalanffy. El tipo de borde mensual de los otolitos sugiere una marca de crecimiento anual. Se identificaron seis grupos de edad (0-5 años), con una APE y CV de 4,5 y 2,9 % respectivamente. El análisis de edad a la talla del conjunto de datos con la selección multimodelo es una garantía de que el caso uno de Schnute es el mejor para describir y estimar los parámetros de crecimiento de O. bulleri del sur del Golfo de California.

Abstract The blue thread herring (Opisthonema bulleri) is part of the landing commercials of small pelagic fishes from the southern Gulf of California; the fishery is certified as sustainable by the Marine Stewardship Council. The growth parameters of this specie are of great interest in the assessment and management of Opisthonema complex fishery. In this study, a data set age-at-size was generated from 367 otolith reads from the years 2005 and 2015 to complete the monthly continuity of one year and infer the formation periodicity of the growth mark. A multi-model approach on five special submodels of the generalized Schnute model, including one equivalent to the von Bertalanffy model, was used. The monthly edge type of otoliths suggests an annual growth mark. Six age groups were identified (0 - 5 years), with an APE and CV of 4.5 and 2.9 %, respectively. The age-at-length analysis of the data set with multi-model selection is a guarantee that Schnute’s case is the best to describe and estimate the growth parameters of O. bulleri from the southern Gulf of California.

Abstract This article constitutes an attempt to articulate productive crossovers between some of the philosophical groundings and theoretical underpinnings on which various schools of phenomenology are based and areas within the practice and theory of psychoanalysis that chime with these. It works ultimately towards establishing a phenomenologico-existential psychoanalysis from these researches, out of which key concepts of illness, structure, situation, and periodicity are excavated; and into which they are incorporated.

Resumen Este artículo constituye un intento de articular cruces productivos entre algunos de los fundamentos filosóficos y las bases teóricas en las que se basan varias escuelas de fenomenología y áreas dentro de la práctica y la teoría del psicoanálisis que coinciden con éstas. En última instancia, trabaja para establecer un psicoanálisis fenomenológico-existencial a partir de estas investigaciones, a partir de las cuales se excavan conceptos clave de enfermedad, estructura, situación y periodicidad; y a las que se incorporan.

Abstract The research examines the relationship between the macroeconomic aggregates of the National Accounts and the Financial Accounts. The research is of an applied type with a qualitative approach, with bibliographic and documentary analysis procedures, including the analysis of the economic activities of “Empresa Internacional S.A”, to demonstrate the interrelationship and equivalence of the accounting economic statements. It was identified that there is a common starting point between the National Accounting and the Financial Accounting, since the macroeconomic aggregates and ledger accounts resort to the accrual basis, use double entry and coincide in the periodicity of their publications. It is shown that the economic and accounting statements are interrelated because both arise from the same and unique fact (economic activity), which only differs in the way in which each one observes it from their own analytical perspective, consequently the proximity is consolidated. between National Accounting and Financial Accounting. The continuous investigation of this field of research by economists, accountants and even statisticians is proposed for the continuous improvement of the information.

Resumen La investigación examina la relación entre los agregados macroeconómicos de la Contabilidad Nacional y los estados financieros de la Contabilidad Financiera. La investigación es de tipo aplicada con un enfoque cualitativo, con procedimientos de análisis bibliográfico y documental. Para demostrar la interrelación y equivalencia de los estados económicos contables, se identificó que existe un punto de partida común entre la Contabilidad Nacional y la Contabilidad Financiera, ya que los agregados macroeconómicos y las cuentas contables recurren a la base del devengado, utilizan la partida doble y coinciden en la periodicidad de sus reportes. El resultado de la investigación demuestra que, los estados económicos y contables están interrelacionados porque ambos surgen de un mismo y único hecho (la actividad económica), el cual solo difiere en la forma en que cada uno lo observa desde su propia perspectiva analítica, consecuentemente se consolida la proximidad entre la Contabilidad Nacional y la Contabilidad Financiera,

Resumen El presente artículo compara los métodos de varianza condicional GARCH y EGARCH, con respecto a la propuesta Fuzzy Gaussian GARCH y Fuzzy Gaussian EGARCH. Se pronosticó la rentabilidad de cuatro tipos de cambio en periodicidad diaria desde enero 2015 a noviembre 2022 y fuera de muestra, enero 2019 y diciembre 2022. Los resultados revelan que los modelos Fuzzy GARCH y Fuzzy EGARCH estiman mejor el comportamiento de la volatilidad de las series del mercado cambiario en comparación con las técnicas tradicionales. Por lo que, la recomendación es estimar otras variables de alta volatilidad para verificar la eficiencia de las técnicas difusas, sin embargo, la principal limitación es que no es posible aplicar las pruebas econométricas tradicionales para técnicas difusas porque los parámetros no son estimados con el logaritmo de máxima verosimilitud. La estimación de los parámetros de los modelos GARCH y EGARCH con teoría difusa es la propuesta de originalidad. En conclusión, las metodologías difusas tienen menos error al pronosticar la volatilidad de los tipos de cambio dentro muestra y fuera de muestra.

Abstract This article discusses a comparison of the GARCH and EGARCH conditional variance methods, with respect to the Fuzzy Gaussian GARCH and Fuzzy Gaussian EGARCH. The returns of four exchange rates were forecasted at daily periodicity from January 2015 to November 2022 and out-of-sample, January 2019, and December 2022. The results indicate that the Fuzzy GARCH and Fuzzy EGARCH models better estimate the volatility behaviour of the exchange market series compared to traditional techniques. Therefore, the recommendation is to estimate other high volatility variables to verify the efficiency of the fuzzy techniques, however, the main limitation is that it is not possible to apply traditional econometric tests for fuzzy techniques because the parameters are not estimated with the logarithm of maximum likelihood. The estimation of the parameters of GARCH and EGARCH models with fuzzy theory is the originality proposal. In conclusion, fuzzy methodologies have less error in forecasting the volatility of in-sample and out-of-sample exchange rates.

Abstract We incorporate almost periodic functions in a mosquito model to take into account a loss of synchronicity in the population dynamics of mosquitoes due to climate change. The model takes into account the skip oviposition strategy that is associated with the mosquitoes that are vectors of infectious diseases as dengue, malaria and leishmaniasis. We prove existence and uniqueness of a stable almost periodic solution for some conditions over the parameters of the model. Numerical simulations are performed using values estimated for the life cycle of Aedes albopictus gathered in literature. The results show that the vector population can be underestimated or overestimated if an almost periodic dynamics is approximated by a periodic dynamics. Therefore, using an almost seasonal model can be more adequate to design breeding habitat-targeted mosquito control strategies when seasonal drivers are modeled since climate-mediated shifts can induce a loss of periodicity in environmental drivers.

Abstract: This paper aims to provide elements that enrich the debate on the usefulness of the temporary cut in International Relations established in the Peace of Westphalia. To this end, a historical overview of diplomacy from the ancient world to 1648 is made, which shows that diplomatic tools such as those used to reach the peace treaties of Osnabrück and Münster were developed from antiquity in the four civilizational foci of Eurasia. Then, this knowledge was synthesized in Constantinople and returned to Europe through Venice. The relevance of this work is linked to its inclusion in the debate on the periodicity of the object of study in International Relations and the history of this discipline.

Resumen: El objetivo de este artículo es aportar elementos que enriquezcan el debate sobre la utilidad del corte temporal de las Relaciones Internacionales establecido en la Paz de Westfalia. Con este fin, se realiza un recorrido histórico de la diplomacia, desde el mundo antiguo hasta 1648, en el que se muestra que herramientas diplomáticas como las que se emplearon para alcanzar los tratados de paz de Osnabrück y Münster, se desarrollaron desde la Antigüedad en los cuatro focos civilizatorios de Eurasia, se sintetizaron en Constantinopla y volvieron a Europa a través de Venecia. La relevancia de este trabajo está vinculada con su inclusión en el debate sobre la periodicidad del objeto de estudio de las relaciones internacionales y la historia de esta disciplina.

Abstract This document aims to analyze the Social Infrastructure Fund for Entities, a tool used by the Mexican Government to reduce extreme poverty and social backwardness, through the construction of basic social infrastructure. Subsequently, based on socioeconomic indicators collected between 2010 and 2020, the problem was analyzed based on the Logical Framework Approach, the only one accepted for the design of public policies in Mexico, proposing adjustments to the fund, as well as the competences of each of the levels of government involved, must apply in order to improve the impact on the indicators. The periodicity of the distribution of the resources, the publication of the legal framework in a clear and timely manner, professionalization and innovation, as well as accountability, are desirable in the management of the fund.

Resumen El presente documento tiene como finalidad analizar el Fondo de Infraestructura Social Estatal, herramienta utilizada por el Estado mexicano para reducir la pobreza extrema y el rezago social, mediante la construcción de infraestructura social básica. Posteriormente, con base en indicadores socioeconómicos recolectados entre los años 2010 y 2020, se analizó la problemática a partir de la Metodología del Marco Lógico, única aceptada para el diseño de políticas públicas en México, proponiéndose diversas adecuaciones al fondo, así como de las competencias de cada uno de los niveles de gobierno involucrados, debe realizar para mejorar el impacto sobre los indicadores que se atienden. La periodicidad de la distribución de recursos, la publicación del marco normativo de forma clara y oportuna, la profesionalización e innovación, así como la rendición de cuentas, resultan deseables en la gestión del fondo.

ABSTRACT Background: Omalizumab (OMA) is approved for antihistamine resistant chronic spontaneous urticaria (CSU). The possibility of self-administration (SA), is particularly convenient in current pandemic scenario, avoiding commutements to the hospital. Objectives: CSU control, SA safety, satisfaction, and cost reduction for patients under OMA SA therapy, during a period ≥ 12 weeks and after 2 training sessions in Outpatient Hospital Care (OHC) were evaluated between January and June 2021. Methods: A questionnaire (30 questions) was applied for the characterization of clinical/demographic data, therapy, adverse reactions (AR) and advantages/concerns related to OMA SA. Clinical evaluation of CSU was performed in T0 (last administration in OHC) and T1 (at12 weeks on SA), by urticaria activity score in the last 7 days (UAS7), urticaria control test (UCT) and dermatology life quality index (DLQI). Results: Twenty-five patients with a mean CSU duration of 7.4 ±3.9 years and under OMA for 3.2 ±1.9 years were included. At the time of the questionnaire, 52% had already 3 SA of OMA 300mg, with variable periodicity between 4/4 week (44%) and 8/8 week (12%); 40% without antihistamine H1 (anti-H1) therapy associated. In 88% OMA was SA by patient himself. 64% perceived equal pain intensity with SA than in OHC administration. No serious AR were reported. Regarding the control of CSU, there were no statistically significant differences between scores in T0 and T1. SA was considered advantageous by all patients, being valued the reduction of time/costs. About 48% reported some concerns with SA, especially in OMA manipulation. The majority (76%) considered a simple and practical procedure, valuing initial training sessions in OHC. For 52% there was no need for further improvement, while the simplification of the OMA delivery process was proposed by 28% of patients. Conclusions: OMA SA had a positive impact on satisfaction in patients with CSU, keeping up the good control and therapeutic safety.

RESUMO Fundamentos: O omalizumab (OMA) está aprovado para a urticária crónica espontânea (UCE) refratária aos anti-histamínicos. A possibilidade de autoadministração (AA) de OMA evita deslocações ao hospital, particularmente relevante em tempo de pandemia. Objetivos: Avaliaram-se o controlo da UCE, segurança da AA de OMA, grau de satisfação e redução dos custos para os doentes sob OMA em AA por período igual ou superior a 12 semanas e após duas sessões de ensino em Hospital de Dia (HD), entre janeiro e junho de 2021. Métodos: Aplicou-se um questionário(30 perguntas) visando a caracterização clínica/demográfica, terapêutica, reações adversas (RA), vantagens/preocupações percecionadas e avaliação de UCE em T0 (última administração em HD) e T1 (12 semanas em AA), por score de atividade da urticária nos últimos sete dias (UAS7), teste de controlo da urticária (UCT) e índice de qualidade de vida em dermatologia (DLQI). Resultados: Incluíram-se 25 doentes com tempo médio de UCE de 7,4 ±3,9 anos e duração do tratamento com OMA de 3,2 ±1,9 anos. À data do questionário, 52% tinham 3 AA de OMA 300mg, com periodicidade variável entre 4/4 semanas (44%) e 8/8 semanas (12%); 40% sem anti-histamínico associado. Em 88% administrado pelo próprio; 64% relatou igual intensidade de dor na AA face à administração em HD. Não se registaram RA graves. No controlo da UCE não se verificaram diferenças estatisticamente significativas nos scores entre T0 e T1. Todos consideraram a AA vantajosa, valorizando sobretudo a diminuição do tempo/custos despendidos. 48% referiu algum receio na AA, sobretudo na manipulação do OMA. A maioria (76%) considerou o processo simples e prático, valorizando os ensinos prévios em HD; 52% considerou não haver aspetos a melhorar; das sugestões apontadas, 28% referiam-se à simplificação do processo de entrega do OMA. Conclusões: O OMA em AA apresentou impacto positivo na satisfação dos doentes com UCE, mantendo-se o controlo da UCE e segurança terapêutica.

RESUMEN El presente trabajo de investigación aborda la importancia y relación de la educación financiera y los emprendedores, buscando medir mediante una escala adoptada los niveles de educación financiera con énfasis en indicadores básicos de ahorro y deuda. Se utilizó un muestreo aleatorio utilizando como instrumento de recolección de datos encuestas en línea de diseño cuantitativo aplicado a emprendedores hondureños, entre los resultados más relevantes se encontró un alto nivel de educación financiera, destacando mejores indicadores en los que mencionaron haber recibido algún tipo de formación en el tema, los cuales mostraron buenos indicadores en la periodicidad de ahorro y análisis de tasas en créditos, de forma que es importante seguir un plan de desarrollo integral del tema de educación financiera aplicado a los emprendedores y sus necesidades dentro del ámbito hondureño partiendo de sus características específicas.

ABSTRACT This research work addresses the importance and relationship between financial education and entrepreneurs, seeking to measure through an adopted scale the levels of financial education with emphasis on basic indicators of savings and debt. A random sampling was used using quantitative design online surveys applied to Honduran entrepreneurs as a data collection instrument, among the most relevant results a high level of financial education was found, highlighting better indicators in which they mentioned having received some type of training. on the subject, which showed good indicators in the periodicity of savings and analysis of credit rates, so that it is important to follow a comprehensive development plan on the subject of financial education applied to entrepreneurs and their needs within the Honduran environment based on its specific characteristics.

Understanding the concept of periodicity in chemistry allows guiding and defining many aspects related to the structure and reactivity of organic and inorganic compounds. As a result, this topic is almost necessary in a general chemistry course in undergraduate programs. Thus, these lecture notes are intended to present the evolution, description and application in biological systems and agricultural sciences of the concept of periodicity of the properties of chemical elements. In the first part, a brief approach is made on the historical overview of the periodic table of the elements and how its basic organization is. With this information, the concept of periodicity is developed; subsequently, the trends for the periodic properties of the elements are defined and described, namely, atomic, and ionic radius, electronic affinity, energy or potential of ionization, and electronegativity. Finally, potential implications of the periodic properties of the elements in biological systems are explored, illustrating that this concept can be used to understand the dynamics behind these. It should be mentioned that these notes are not intended to replace the review of the concept of chemical periodicity in general chemistry books, but rather to help the student understand the concept. Thus, it is proposed that students apply the concept of chemical periodicity in several areas of their academic training, mainly in those associated with biological and agricultural sciences.

O entendimento do conceito de periodicidade química, permite nortear e definir muitos aspetos relacionados com a estrutura e reatividade dos compostos orgânicos e inorgânicos. Desta forma, este tópico é quase que necessário na disciplina de química geral de qualquer curso de graduação. Assim, esta revisão, tem com finalidade apresentar a evolução, descrição e aplicação em sistemas biológicos e nas ciências agrárias, do conceito de periocidade das propriedades dos elementos químicos. Na primeira parte, realiza-se uma breve abordagem do panorama histórico da tabela periódica dos elementos e como é sua organização básica. Com estas informações, faz-se o desenvolvimento do conceito de periodicidade; posteriormente, são definidas e descritas as tendências para as propriedades periódicas dos elementos, sendo estas, o raio atômico e iónico, afinidade eletrônica, energia ou potencial de ionização e eletronegatividade. Finalmente, exploram-se potenciais implicações das propriedades periódicas dos elementos nos sistemas biológicos e nas ciências agrárias, ilustrando-se, que este conceito pode ser usado para entender a dinâmica atrás destes. É de mencionar, que este documento não pretendem substituir a revisão do conceito de periodicidade química em livros de química geral, é sim auxiliar ao aluno no entendimento deste. Assim, propõe-se ao aluno, que aplique o conceito de periodicidade química em diversas áreas da sua formação acadêmica, principalmente nas associadas às ciências biológicas e agrárias.

Resumen Introducción: El blanqueamiento global coralino refleja la fragilidad del coral a condiciones ambientales adversas y al cambio climático. Porites lobata es la especie de coral hermatípico más abundante actualmente en El Salvador y ha experimentado eventos de blanqueamiento recientes en el área natural protegida Complejo Los Cóbanos. Objetivo: Describir los episodios de blanqueamiento que colonias de P. lobata experimentaron en Los Cóbanos, El Salvador, durante los últimos 18 años, y analizar los esfuerzos de restauración de coral. Métodos: Aproximadamente 2 100 imágenes (2006 - 2022) tomadas sin periodicidad específica de dos sitios fueron revisadas. Parámetros del agua desde 2014 fueron registradas sin una periodicidad temporal definida. Las áreas de estudio fueron son playa El Faro y colonias submareales cerca de un importante resort de playa. La primera área presentó colonias dispersas en una zona intermareal, la otra, colonias más grandes a 2 m de profundidad en marea baja. También, revisar literatura acerca de actividades para restaurar arrecifes dentro del país. Resultados: Varios eventos de blanqueamiento ocurrieron durante este período de observación. Algunos de ellos podrían estar asociados a temperaturas altas del agua de mar (> 30 o C) de mayo a octubre (estación lluviosa), floraciones algales nocivas, así como causas desconocidas. Varios blanqueamientos que causaron pérdida de cobertura de coral en las colonias intermareales ocurrieron durante el evento global (2015-2016). Conclusiones: Blanqueamiento en el Complejo los Cóbanos ocurre en diferentes patrones de intensidad durante la estación lluviosa que comprende niveles de alta temperatura y turbidez en el agua, así como floraciones algales. El episodio de 2015-2016 causó pérdida de cobertura de coral en las colonias intermareales y las submareales experimentaron pequeños daños permanentes (< 5 % mortalidad). Las políticas de restauración nacionales requieren más esfuerzos estratégicos considerando la hidrodinámica y las capacidades institucionales locales.

Abstract Introduction: Global coral bleaching reflects coral fragility to adverse environmental conditions and climate change. Porites lobata is the most abundant hermatypic coral species currently in El Salvador and has experienced recent bleaching events at natural protected area Complejo Los Cóbanos. Objective: To describe the bleaching episodes that colonies of P. lobata experienced at Los Cóbanos, El Salvador, during the last 18 years, and analyze coral restoration efforts. Methods: Approximately 2 100 images (2006 - 2022) taken without specific periodicity from two sites were reviewed. Water parameters since 2014 were registered without defined frequency. The areas sampled were El Faro beach and subtidal colonies near an important beach resort. The first area presented dispersed colonies on an intertidal zone, the other, larger colonies at 2 m deep in low tide. Also, literature about activities to restore reefs within the country was reviewed. Results: Several bleaching events occurred during this observation period. Some of them could be associated to high sea water temperatures (> 30 o C) from May to October (rainy season), others to harmful algae blooms, as well as unknown causes. Severe bleaching that caused loss of coral coverage on intertidal colonies occurred during the global event (2015-2016). Conclusion: Bleaching at Los Cóbanos occurs in different intensity patterns usually during the rainy season that encompasses high temperature and turbidity levels in water, as well as algal blooms. The 2015-2016 episode caused coral coverage loss on the intertidal colonies and subtidal ones experienced little permanent damages (< 5% mortality). National restoration policies for coral colonies require more strategic efforts considering the local littoral hydrodynamics and institutional capabilities.