Flexibility of the imidazolium based ionic liquids/water system for the synthesis of siliceous 10-ring containing microporous frameworks

By using asymmetric di-substituted imidazolium molecules (1-Butyl-3-methylimidazolium (BMIM) and 1-Ethyl-3-methylimidazolium (EMIM) bromide) as the structure directing agents, in combination with simple changes in silica source or sodium/water content it is possible to prepare three pure phase microporous 10-ring siliceous zeolitic structures. The crystallizations are comparatively rapid with fully crystalline material resulting in 1–3 days at 443 K. In contrast to many recipes reported for pure silica materials, the synthesis is performed without the use of HF or without the need to alter the properties of the SDA, while significantly lower amounts of both ionic liquid and mineralizing agent are required. The results obtained indicate that effective phase control can be achieved from a primary gel composition by minor changes to either the silica source or the water/sodium content, with a strong specificity in the formation of topologies with interconnected 10-rings

GRB 180620A: Evidence for Late-time Energy Injection

The early optical emission of gamma-ray bursts (GRBs) gives an opportunity to understand the central engine and first stages of these events. About 30% of GRBs present flares whose origin is still a subject of discussion. We present optical photometry of GRB 180620A with the COATLI telescope and RATIR instrument. COATLI started to observe from the end of prompt emission at T + 39.3 s and RATIR from T + 121.4 s. We supplement the optical data with the X-ray light curve from Swift/XRT. We observe an optical flare from T + 110 s to T + 550 s, with a temporal index decay α O,decay = 1.32 ± 0.01, and Δt/t = 1.63, which we interpret as the signature of a reverse shock component. After the initial normal decay the light curves show a long plateau from T + 500 s to T + 7800 s in both X-rays and the optical before decaying again after an achromatic jet break at T + 7800 s. Fluctuations are seen during the plateau phase in the optical. Adding to the complexity of GRB afterglows, the plateau phase (typically associated with the coasting phase of the jet) is seen in this object after the "normal" decay phase (associated with the deceleration phase of the jet), and the jet break phase occurs directly after the plateau. We suggest that this sequence of events can be explained by a rapid deceleration of the jet with t d ≲ 40 s due to the high density of the environment (≈100 cm-3) followed by reactivation of the central engine, which causes the flare and powers the plateau phase

Voluntariado y las diferentes motivaciones que lo impulsan

The review article sought to answer the question: What are the different motivations that drive volunteering? and the objective is to determine the main motivations that people have for volunteering. The methodology used was qualitative, under the IMRyD format, of a non-systematic review of the scientific literature in the closed access databases EbscoHost and ProQuest and open access Scielo with a total of 18 articles selected under an intentional non-probabilistic sampling that had As inclusion criteria, only articles in English, Spanish and Portuguese, that answered the research question, between the years 2018 to 2023 and with a DOI identifier. The results showed that the authors pointed out the existence of different motivators to carry out volunteering, being a multi-motivated activity and that, for the most part, they can be grouped into internal (intrinsic) motivators of the person such as faith, values, strong personal desire, overcoming problems, the feeling of success, the experiences lived, etc. and external (extrinsic) such as the influence of family, friends, the community, the environment where volunteering takes place, among others. It was concluded that there are different motivators for volunteering that should be taken into account to carry out a correct combination of strategies that consider both aspects and to be able to attract and retain more volunteers, making the various programs executed sustainable. The limitations were the closed access that other important databases have that could not be included.El artículo de revisión buscó responder la pregunta ¿Cuáles son las diferentes motivaciones que impulsan el voluntariado? y como objetivo determinar las principales motivaciones que tienen las personas para realizar voluntariado. La metodología empleada fue cualitativa, bajo el formato IMRyD, de revisión no sistemática de la literatura científica en las bases de datos de acceso cerrado EbscoHost y ProQuest y de acceso abierto Scielo con un total de 18 artículos seleccionados bajo un muestreo no probabilístico intencional que tuvo como criterios de inclusión sólo los artículos en inglés, español y portugués, que respondieran la pregunta de investigación, entre los años 2018 al 2023 y con identificador DOI. Los resultados demostraron que los autores señalaron la existencia de diferentes motivadores para realizar el voluntariado, siendo una actividad polimotivada y que, en su mayoría, se pueden agrupar en motivadores internos (intrínsecos) propios de la persona como la fe, los valores, el fuerte deseo  personal, la superación de problemas, la sensación de éxito, las experiencias vividas, etc. y externos (extrínsecos) como la influencia de la familia, amigos, la comunidad, el ambiente donde se desarrolla el voluntariado, entre otros. Se concluyó que existen diferentes motivadores para realizar el voluntariado que deberían ser tomados muy en cuenta para realizar una correcta combinación de estrategias que consideren ambos aspectos y poder captar y retener más voluntarios haciendo sostenibles los diversos programas ejecutados. Las limitaciones fueron el acceso cerrado que tienen otras bases de datos importantes que no pudieron ser incluidas

Development of efficient recirculation system for Tilapia (Oreochromis niloticus) culture using low cost materials

In the current experiment, a recirculation system was built using low cost materials that are available locally and its performance was tested. The performance evaluation procedure was carried out in an aquaculture system in greenhouse with sex-reversed male Nile tilapia (Oreochromis niloticus) production in Querétaro State, Mexico. The recirculation system had four sections (sediment collector, gravel and sand filters, biofilter and clarification) in order to eliminate the organic matter produced by the fish excretion material and uneaten food, as well as, the nitrogenous compounds undesirable in the water tanks, such as, total ammonia nitrogen (TAN). The monitored variables include: temperature, dissolved oxygen, pH, visibility, TAN, nitrites and nitrates. The obtained data were compared with previous studies to evaluate the achieved state of the system. This research clearly demonstrated that it is feasible to use the proposed configuration in aquaculture systems in areas where water source is limited. Consequently, the obtained results represent an environmental standpoint for the conservation of water use in the aquaculture industry and also constitute an important contribution to the aquaculture and farmers who receive minimal economic support.Key words: Water recirculation, aquaculture, sustainability, low cost, water use efficiency

Mental health problems and resilience in adolescents during the COVID-19 pandemic in a post-armed conflict area in Colombia.

The impact of COVID-19 pandemic on mental health of adolescents are emerging and require particular attention in settings where challenges like armed conflict, poverty and internal displacement have previously affected their mental wellbeing. This study aimed to determine the prevalence of anxiety symptoms, depressive symptomatology, probable post-traumatic stress disorder and resilience in school-attending adolescents in a post-conflict area of Tolima, Colombia during the COVID-19. A cross-sectional study was carried out with 657 adolescents from 12 to 18 years old, recruited by convenience sampling in 8 public schools in the south of Tolima, Colombia, who completed a self-administered questionnaire. Mental health information was obtained through screening scales for anxiety symptoms (GAD-7), depressive symptomatology (PHQ-8), probable post-traumatic stress disorder (PCL-5) and resilience (CD-RISC-25). The prevalence observed for moderate to severe anxiety symptoms was 18.9% (95% CI 16.0-22.1) and for moderate to severe depressive symptomatology was 30.0% (95% CI 26.5-33.7). A prevalence of probable post-traumatic stress disorder (PTSD) of 22.3% (95% CI 18.1-27.2) was found. The CD-RISC-25 results for resilience had a median score of 54 [IQR 30]. These results suggest that approximately two-thirds of school-attending adolescents in this post-conflict area experienced at least one mental health problem such as anxiety symptoms, depressive symptomatology or probable PTSD during the COVID-19 pandemic. Future studies are of interest to establish the causal relationship between these findings and the impact of the pandemic. These findings highlight the challenge that schools have after pandemic to address the mental health of their students in order to promoting adequate coping strategies and implement prompt multidisciplinary interventions to reduce the burden of mental health problems in adolescents

Posmodernidad y ética empresarial. Una Hipótesis sobre el auge de la responsabilidad social corporativa

This paper develops a hypothesis about the reasons that have led to the success of the Corporate Social Responsibility concept, both on literature and in business management practice. The hypothesis is created on the basis of management trends theory and it suggests the existence of elective affinities, within the Weberian meaning of the term, between the spread of Corporate Social Responsibility and the advent of postmodern society. Este artículo desarrolla una hipótesis sobre las razones que han conducido al éxito del concepto de Responsabilidad Social Corporativa (RSC) tanto en la literatura como en la práctica de la gestión empresarial. La hipótesis se construye a partir de la teoría de las modas en la gestión y propone la existencia de afinidades electivas, en el sentido weberiano del término, entre la extensión de las políticas de RSC y el advenimiento de la sociedad posmoderna.

Environmentally friendly analysis of emerging contaminants by pressurized hot water extraction-stir bar sorptive extraction-derivatization and gas chromatography-mass spectrometry

This work describes the development, optimiza- tion, and validation of a new method for the simultaneous determination of a wide range of pharmaceuticals (beta- blockers, lipid regulators ... ) and personal care products (fragrances, UV filters, phthalates ... ) in both aqueous and solid environmental matrices. Target compounds were extracted from sediments using pressurized hot water ex- traction followed by stir bar sorptive extraction. The first stage was performed at 1,500 psi during three static extrac- tion cycles of 5 min each after optimizing the extraction temperature (50 – 150 °C) and addition of organic modifiers (% methanol) to water, the extraction solvent. Next, aqueous extracts and water samples were processed using polydime- thylsiloxane bars. Several parameters were optimized for this technique, including extraction and desorption time, ionic strength, presence of organic modifiers, and pH. Fi- nally, analytes were extracted from the bars by ultrasonic irradiation using a reduced amount of solvent (0.2 mL) prior to derivatization and gas chromatography – mass spectrome- try analysis. The optimized protocol uses minimal amounts of organic solvents (<10 mL/sample) and time ( ≈ 8 h/sam- ple) compared to previous ex isting methodologies. Low standard deviation (usually below 10 %) and limits of de- tection (sub-ppb) vouch for the applicability of the method- ology for the analysis of target compounds at trace levels. Once developed, the method was applied to determin