Molecular Distribution, 13C-Isotope, and Enantiomeric Compositions of Carbonaceous Chondrite Monocarboxylic Acids

The watersoluble organic compounds in carbonaceous chondrite meteorites constitute a record of the synthetic reactions occurring at the birth of the solar system and those taking place during parent body alteration and may have been important for the later origins and development of life on Earth. In this present work, we have developed a novel methodology for the simultaneous analysis of the molecular distribution, compoundspecific 13C, and enantiomeric compositions of aliphatic monocarboxylic acids (MCA) extracted from the hotwater extracts of 16 carbonaceous chondrites from CM, CR, CO, CV, and CK groups. We observed high concentrations of meteoritic MCAs, with total carbon weight percentages which in some cases approached those of carbonates and insoluble organic matter. Moreover, we found that the concentration of MCAs in CR chondrites is higher than in the other meteorite groups, with acetic acid exhibiting the highest concentration in all samples. The abundance of MCAs decreased with increasing molecular weight and with increasing aqueous and/or thermal alteration experienced by the meteorite sample. The 13C isotopic values of MCAs ranged from 52 to +27, and aside from an inverse relationship between 13C value and carbon straightchain length for C3C6 MCAs in Murchison, the 13Cisotopic values did not correlate with the number of carbon atoms per molecule. We also observed racemic compositions of 2methylbutanoic acid in CM and CR chondrites. We used this novel analytical protocol and collective data to shed new light on the prebiotic origins of chondritic MCAs

Analyses of Aliphatic Aldehydes and Ketones in Carbonaceous Chondrites

Aliphatic aldehydes and ketones are essential building blocks for the synthesis of more complex organic compounds. In spite of their potentially key role as precursors of astrobiologically-important molecules, such as amino acids and carboxylic acids, this family of compounds has scarcely been evaluated in carbonaceous chondrites. The paucity of such analyses likely derives from the low concentration of aldehydes and ketones in the meteorites, and from the currently used chromatographic methodologies that have not been optimized for meteorite analysis. In this work, we report the development of a novel analytical method to quantify the molecular distribution and compound-specific isotopic analysis of 29 aliphatic aldehydes and ketones. Using this method, we have investigated the molecular distribution and 13C-isotopic composition of aldehydes and ketones in ten carbonaceous chondrites from the CI, CM, CR and CV groups. The total concentration of carbonyl compounds ranged from 130 to 1000 nmolg-1 of meteorite, with formaldehyde, acetaldehyde, and acetone being the most abundant species in all investigated samples. The 13C-isotopic values ranged from 67 to +64 and we did not observe clear relationships between 13C-content and molecular weight. Accurately measuring the relative abundances, determining the molecular distribution, and isotopic composition of chondritic organic compounds is central in assessing both their formation chemistry and synthetic relationships

Pathways to Meteoritic Glycine and Methylamine

Glycine and methylamine are meteoritic water-soluble organic compounds that provide insights into the processes that occurred before, during, and after the formation of the Solar System. Both glycine and methylamine and many of their potential synthetic precursors have been studied in astrophysical environments via observations, laboratory experiments, and modeling. Despite these studies, the synthetic mechanisms for their formation leading to their occurrence in meteorites remain poorly understood. Typical 13C-isotopic values (13C) of meteoritic glycine and methylamine are 13C-enriched relative to their terrestrial counterparts; thus, analyses of their stable carbon isotopic compositions (13C/12C) may be used not only to assess terrestrial contamination in meteorites but also to provide information about their synthetic routes inside the parent body. Here, we examine potential synthetic routes of glycine and methylamine from a common set of precursors present in carbonaceous chondrite meteorites, using data from laboratory analyses of the well-studied CM2 Murchison meteorite. Several synthetic mechanisms for the origins of glycine and methylamine found in carbonaceous chondrites may be possible, and the prevalence of these mechanisms will largely depend on (a) the molecular abundance of the precursor molecules and (b) the levels of processing (aqueous and thermal) that occurred inside the parent body. In this work, we also aim to contextualize the current knowledge about gas-phase reactions and irradiated ice grain chemistry for the synthesis of these species through parent body processes. Our evaluation of various mechanisms for the origins of meteoritic glycine and methylamine from simple species shows what work is still needed to evaluate both the abundances and isotopic compositions of simpler precursor molecules from carbonaceous chondrites as well as the effects of parent body processes on those abundances and isotopic compositions. The analyses presented here combined with the indicated measurements will aid a better interpretation of quantitative analysis of reaction rates, molecular stability, and distribution of organic products from laboratory simulations of interstellar ices, astronomical observations, and theoretical modeling

Compound-specific Carbon Isotope Compositions of Aldehydes and Ketones in the Murchison Meteorite

Compoundspecific carbon isotope analysis (13C) of meteoritic organic compounds can be used to elucidate the abiotic chemical reactions involved in their synthesis. The soluble organic content of the Murchison carbonaceous chondrite has been extensively investigated over the years, with a focus on the origins of amino acids and the potential role of Streckercyanohydrin synthesis in the early solar system. Previous 13C investigations have targeted amino acid and hydroxy acid Strecker products and reactant HCN; however, 13C values for meteoritic aldehydes and ketones (Strecker precursors) have not yet been reported. As such, the distribution of aldehydes and ketones in the cosmos and their role in prebiotic reactions have not been fully investigated. Here, we have applied an optimized O(2,3,4,5,6pentafluorobenzyl)hydroxylamine (PFBHA) derivatization procedure to the extraction, identification, and 13C analysis of carbonyl compounds in the Murchison meteorite. A suite of aldehydes and ketones, dominated by acetaldehyde, propionaldehyde, and acetone, were detected in the sample. 13C values, ranging from 10.0 to +66.4, were more 13Cdepleted than would be expected for aldehydes and ketones derived from the interstellar medium, based on interstellar 12C/13C ratios. These relatively 13Cdepleted values suggest that chemical processes taking place in asteroid parent bodies (e.g., oxidation of the IOM) may provide a secondary source of aldehydes and ketones in the solar system. Comparisons between 13C compositions of meteoritic aldehydes and ketones and other organic compound classes were used to evaluate potential structural relationships and associated reactions, including Strecker synthesis and alterationdriven chemical pathways

New Insights into the Heterogeneity of the Tagish Lake Meteorite: Soluble Organic Compositions of Variously Altered Specimens

The Tagish Lake carbonaceous chondrite exhibits a unique compositional heterogeneity that may be attributed to varying degrees of aqueous alteration within the parent body asteroid. Previous analyses of soluble organic compounds from four Tagish Lake meteorite specimens (TL5b, TL11h, TL11i, TL11v) identified distinct distributions and isotopic compositions that appeared to be linked to their degree of parent body processing (Herd et al. 2011; Glavin et al. 2012; Hilts et al. 2014). In the present study, we build upon these initial observations and evaluate the molecular distribution of amino acids, aldehydes and ketones, monocarboxylic acids, and aliphatic and aromatic hydrocarbons, including compoundspecific 13C compositions, for three additional Tagish Lake specimens: TL1, TL4, and TL10a. TL1 contains relatively high abundances of soluble organics and appears to be a moderately altered specimen, similar to the previously analyzed TL5b and TL11h lithologies. In contrast, specimens TL4 and TL10a both contain relatively low abundances of all of the soluble organic compound classes measured, similar to TL11i and TL11v. The organicdepleted composition of TL4 appears to have resulted from a relatively low degree of parent body aqueous alteration. In the case of TL10a, some unusual properties (e.g., the lack of detection of intrinsic monocarboxylic acids and aliphatic and aromatic hydrocarbons) suggest that it has experienced extensive alteration and/or a distinct organicdepleted alteration history. Collectively, these varying compositions provide valuable new insights into the relationships between asteroidal aqueous alteration and the synthesis and preservation of soluble organic compounds

Incidence of Tuberculosis Among Young Children in Rural Mozambique

BACKGROUND: Tuberculosis (TB) contributes significantly to child morbidity and mortality. This study aimed to estimate the minimum community-based incidence rate of TB among children <3 years of age in Southern Mozambique. METHODS: Between October 2011 and October 2012, in the Manhica District Health and Demographic Surveillance System, we enrolled prospectively all presumptive TB cases younger than 3 years of age through passive and active case finding. Participants included all children who were either symptomatic or were close contacts of a notified adult smear-positive pulmonary TB. Children were clinically evaluated at baseline and follow-up visits. Investigation for TB disease included chest radiography, HIV and tuberculin skin testing as well as gastric aspirate and induced sputum sampling, which were processed for smear, culture and mycobacterial molecular identification. RESULTS: During the study period, 13,764 children <3 years contributed to a total of 9575 person-year. Out of the 789 presumptive TB cases enrolled, 13 had TB culture confirmation and 32 were probable TB cases. The minimum community-based incidence rate of TB (confirmed plus probable cases) was 470 of 100,000 person-year (95% confidence interval: 343-629 of 100,000). HIV co-infection was present in 44% of the TB cases. CONCLUSION: These data highlight the huge burden of pediatric TB. This study provides one of the first prospective population-based incidence data of childhood tuberculosis and adds valuable information to the global effort of producing better estimates, a critical step to inform public health policy

Seguridad alimentaria y satisfacción del usuario del programa Qali Warma en instituciones educativas de la región San Martín - 2024

La presente investigación se centró en atender el objetivo ODS 2, reducción del hambre, es decir, que todos tengan acceso a alimentos de calidad y el ODS 3, que es el fortalecimiento de la buena salud. Tuvo como objetivo principal determinar la relación entre la seguridad alimentaria y satisfacción del usuario del programa Qali Warma en instituciones educativas de la región San Martín - 2024. El estudio fue de tipo básica y de diseño descriptivo correlacional. La población estuvo conformada por 260 padres de familia y la muestra, 194. Se aplicó la técnica de la encuesta y como instrumentos dos cuestionarios. Los resultados fueron que el 51% de los encuestados considera que la seguridad alimentaria es alta, además que el 75.8% afirmó un grado de satisfacción media con respecto al programa Qali Warma. Se concluyó que, existe relación positiva baja y significativa entre las variables seguridad alimentaria y satisfacción, con un Rho de Spearman de 0.327, y un nivel de significancia del 0,01. El coeficiente de determinación fue del 34.37% lo que demostró la variabilidad que existe entre las variables

Diseño estructural de una vivienda económica utilizando el sistema steel framing en la urbanización San Gabriel Arcángel Castilla, Piura

En el Perú para las construcciones de viviendas se utiliza el sistema de albañilería confinada, el cual tiende a ser costoso y de largo tiempo de ejecución. Por otro lado, existe una falta de compromiso por parte del Estado en cuanto a responder a las necesidades de las poblaciones más vulnerables. Por ello, por medio de una investigación “básica” y un diseño de investigación “investigación-acción”, proponemos un diseño estructural utilizando el sistema Steel Framing basado en la metodología BIM para una propietaria de la UPIS San Gabriel Arcángel, la cual cuenta con un lote de 160 m2. Se obtuvo un correcto diseño y modelado de todas las especialidades constructivas; una estructura sismorresistente que cumple con los parámetros establecidos por las normas empleadas (peruanas y norteamericanas) y un ahorro del 35.78% frente al sistema de albañilería confinada. Por ello, el sistema Steel Framing, es un método constructivo que posee demasiados beneficios, y en lo que más destaca en base a nuestra investigación es, económico, tiempo de ejecución rápido, menores desperdicios de materiales y sobre todo posee características sismorresistentes debido que al usar materiales constructivos livianos con resistencia a la deformación lo hacen un sistema seguro frente a eventuales movimientos telúricos

Cartografía temática de las investigaciones realizadas por los estudiantes de la especialización en salud ocupacional, en el área urbana de Cali, Colombia. Material Suplementario # 2: Cartografía Sector Industrial: Material Suplementario #2: Cartografia Sector Industrial

1. EVALUACION DE LA GESTION DEL PROGRAMA DE SALUD OCUPACIONAL DE LA EMPRESA FRUTOS DEL SOL DE LA CIUDAD DE CALI. Trabajo de grado. Facultad de Ciencias de la Salud, Programa Especialización En Salud Ocupacional, (2006) 68p. (Contiene: cuadros, graficas, tablas, encuestas). Línea de investigación: gestión y administración. Asesor: Reynaldo Carvajal. DURAN HERNANDEZ, Celmy; MUÑOZ MORILLO, Orlando; VELEZ, Francia Lorena; ZAFRA MARTINEZ, Sandra. El trabajo de grado contiene un estudio descriptivo de prevalencia, que evalúa la gestión del programa de salud ocupacional de la empresa FRUTOS DEL SOL, frente a los requerimientos legales básicos establecidos por el Ministerio de Trabajo y Seguridad Social y mide el conocimiento que se tiene por parte de sus colaboradores del PSOE