Caracterización de la materia orgánica en el efluente de un reactor nitrificante utilizando espectroscopia de fluorescencia

La espectroscopia de fluorescencia es una herramienta analítica utilizada para examinar muestras de agua de diferente origen por que es sensible, selectiva y puede dar un amplio espectro de información sobre la composición, características, origen y distribución de la materia orgánica disuelta (MOD). El objetivo de esta investigación fue caracterizar la MOD en el efluente de un reactor aerobio autotrófico nitrificante por espectrometría de fluorescencia de la matriz de excitación-emisión en 3D (EEM- 3D, por sus siglas en inglés) y así determinar si las EEM-3D podrían identificar productos microbianos solubles de bacterias nitrificantes. El reactor nitrificante fue operado a 36 días de tiempo de retención celular (TRC), 40 horas de tiempo de retención hidráulico (TRH) y alimentado con agua residual con exceso de amonio. Se identificaron solamente dos picos de fluorescencia en el efluente del reactor nitrificante: Los picos fueron localizados a una longitud de onda de emisión similar (416.9 10.3 y 415.5 2.2 nm, respectivamente), pero a diferentes longitudes de onda de excitación (245.2 1.0 y 330.7 1.7 nm, respectivamente). Las EEM-3D fueron significativamente diferentes a los que comúnmente se encuentran en el efluente de reactores aerobios heterotróficos de lodos activados o en el efluente de reactores anaerobios heterotróficos metanogénicos

Fraccionamiento de DQO del agua residual de Toluca por el protocolo STOWA

El modelo número 1 de lodos activados (ASM1), publicado en 1987, hoy es utilizado de manera amplia. La generación de una base de datos de padrones típicos de fraccionamiento de DQO para las aguas residuales municipales (ARM) en México y en América Latina facilitaría el uso de la modelación dinámica y de los simuladores de plantas de tratamiento en la sub-región. En este trabajo se aplicó el protocolo físico-químico de caracterización propuesto por la Asociación Holandesa de Investigación Aplicada al Agua (STOWA), para determinar el patrón de fraccionamiento de la DQO en las aguas residuales de la ciudad de Toluca. También se realizaron pruebas respirométricas para hallar el valor de algunos de los parámetros cinéticos del ASM1, así como para investigar la cantidad de biomasa heterótrofa ( X H 0 ) inicialmente presente en las aguas residuales. Las tasas de crecimiento (μ H máx ) y de decaimiento ( b H ) a 20 °C fueron 5.7 y 0.54 d -1 , mientras X H 0 representó hasta el 14% de la DQO total. El padrón de fraccionamiento promedio de la DQO en el ARM pre-sedimentada fue 13% de DQO soluble inerte ( S I ), 23% de sustrato fácilmente biodegradable ( S S ), 48% de DQO lentamente biodegradable ( X S ) y 16% de DQO particulada inerte ( X I ). Con respecto a la fracción S S , hubo grandes divergencias entre los valores obtenidos por respirometría ( S S -respiro ) y los derivados por vía físico-química ( S S -físico ). Las contradicciones entre S S -respiro y S S -físico , y los problemas de medición de DBO fueron las principales dificultades notadas durante la implementación del protocolo STOWA en el ámbito local

Validity of Machine Learning in Assessing Large Texts Through Sustainability Indicators

As machine learning becomes more widely used in policy and environmental impact settings, concerns about accuracy and fairness arise. These concerns have piqued the interest of researchers, who have advanced new approaches and theoretical insights to enhance data gathering, treatment and models’ training. Nonetheless, few works have looked at the trade-offs between appropriateness and accuracy in indicator evaluation to comprehend how these constraints and approaches may better redound into policymaking and have a more significant impact across culture and sustainability matters for urban governance. This empirical study fulfils this void by researching indicators’ accuracy and utilizing algorithmic models to test the benefits of large text-based analysis. Here we describe applied work in which we find affinity and occurrence in indicators trade-offs that result be significant in practice to evaluate large texts. In the study, objectivity and fairness are kept substantially without sacrificing accuracy, explicitly focusing on improving the processing of indicators to be truthfully assessed. This observation is robust when cross-referring indicators and unique words. The empirical results advance a novel form of large text analysis through machine intelligence and refute a widely held belief that artificial intelligence text processing necessitates either accepting a significant reduction in accuracy or fairness.Funding for open access charge: CRUE-Universitat Jaume

Genes and pathways for CO2 fixation in the obligate, chemolithoautotrophic acidophile, Acidithiobacillus ferrooxidans, Carbon fixation in A. ferrooxidans

<p>Abstract</p> <p>Background</p> <p><it>Acidithiobacillus ferrooxidans </it>is chemolithoautotrophic γ-proteobacterium that thrives at extremely low pH (pH 1-2). Although a substantial amount of information is available regarding CO₂uptake and fixation in a variety of facultative autotrophs, less is known about the processes in obligate autotrophs, especially those living in extremely acidic conditions, prompting the present study.</p> <p>Results</p> <p>Four gene clusters (termed <it>cbb1-4</it>) in the <it>A. ferrooxidans </it>genome are predicted to encode enzymes and structural proteins involved in carbon assimilation via the Calvin-Benson-Bassham (CBB) cycle including form I of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO, EC 4.1.1.39) and the CO₂-concentrating carboxysomes. RT-PCR experiments demonstrated that each gene cluster is a single transcriptional unit and thus is an operon. Operon <it>cbb1 </it>is divergently transcribed from a gene, <it>cbbR</it>, encoding the LysR-type transcriptional regulator CbbR that has been shown in many organisms to regulate the expression of RubisCO genes. Sigma⁷⁰-like -10 and -35 promoter boxes and potential CbbR-binding sites (T-N₁₁-A/TNA-N₇TNA) were predicted in the upstream regions of the four operons. Electrophoretic mobility shift assays (EMSAs) confirmed that purified CbbR is able to bind to the upstream regions of the <it>cbb1</it>, <it>cbb2 </it>and <it>cbb3 </it>operons, demonstrating that the predicted CbbR-binding sites are functional <it>in vitro</it>. However, CbbR failed to bind the upstream region of the <it>cbb4 </it>operon that contains <it>cbbP</it>, encoding phosphoribulokinase (EC 2.7.1.19). Thus, other factors not present in the assay may be required for binding or the region lacks a functional CbbR-binding site. The <it>cbb3 </it>operon contains genes predicted to encode anthranilate synthase components I and II, catalyzing the formation of anthranilate and pyruvate from chorismate. This suggests a novel regulatory connection between CO₂fixation and tryptophan biosynthesis. The presence of a form II RubisCO could promote the ability of <it>A. ferrooxidans </it>to fix CO₂at different concentrations of CO₂.</p> <p>Conclusions</p> <p><it>A. ferrooxidans </it>has features of <it>cbb </it>gene organization for CO₂-assimilating functions that are characteristic of obligate chemolithoautotrophs and distinguish this group from facultative autotrophs. The most conspicuous difference is a separate operon for the <it>cbbP </it>gene. It is hypothesized that this organization may provide greater flexibility in the regulation of expression of genes involved in inorganic carbon assimilation.</p

A simple DC-UPS based in forward-forward topology, design and simulation

This paper presents the analysis, design and simulation of a simple DC-UPS converter with integrated back-up and automatic transition. This converter makes automatic transitions between the main AC and the battery when a failure occurs; and it delivers uninterrupted DC power to the load through two independent power sources of commercial input power and battery power. The converter has the following characteristics: automatic transition between the main and the battery, no additional control to detect failure in main, single structure, galvanic isolation, multi output voltages capability and only one switch control for two operation modes: normal and back-up. The analysis, design and simulation for this converter are presented

Isolated DC-DC UPS based in a forward-forward converter analysis and design

This paper presents the analysis, design and simulation from a simple DC-UPS converter with integrated back-up and automatic transition. This converter makes automatic transition between the main AC and the battery when a failure occurs, and it delivers uninterrupted DC power to the load through two independent power sources of commercial input power and battery power. The converter has the following characteristics: automatic transition between the main and the battery, no additional control to detect failure in the main, single structure, galvanic isolation, multi output voltages capability and only one switch control for two operation modes normal and back-up. The analysis, design, simulation and experimental results for this converter are presented

Reducción de color con cloruro de magnesio en soluciones con colorantes comerciales

Se experimentó con diferentes concentraciones de cloruro de magnesio (MgCl2) como coagulante para reducir el color en soluciones con colorantes comerciales: negro, azul y café. Los parámetros analizados fueron pH, color, demanda química de oxígeno ( dqo ) y sólidos suspendidos totales (sst) de acuerdo con las Normas Mexicanas. Como prueba complementaria se agregó carbón activado a las muestras para reducir el color residual después de la coagulación-floculación. La reducción de los valores de color y dqo fue mayor cuando se adicionó más cantidad de MgCl2 (1.8 g/L). Los porcentajes de reducción fueron 90% para el color y >50% para la dqo. Los sst aumentaron con la adición de MgCl2. El carbón activado eliminó el color residual

Reducción de color con cloruro de magnesio en soluciones con colorantes comerciales

Se experimentó con diferentes concentraciones de cloruro de magnesio (MgCl2) como coagulante para reducir el color en soluciones con colorantes comerciales: negro, azul y café. Los parámetros analizados fueron pH, color, demanda química de oxígeno (DQO) y sólidos suspendidos totales (SST) de acuerdo con las Normas Mexicanas. Como prueba complementaria se agregó carbón activado a las muestras para reducir el color residual después de la coagulación-floculación. La reducción de los valores de color y dqo fue mayor cuando se adicionó más cantidad de MgCl2 (1.8 g/L). Los porcentajes de reducción fueron ≥90% para el color y >50% para la DQO. Los SST aumentaron con la adición de MgCl2. El carbón activado eliminó el color residual. (The aim of this study was to experiment with different concentrations of magnesium chloride (MgCl2) as a coagulant to reduce the color in commercial dye solutions: black, blue and brown. The parameters analyzed according to the Mexican Standards were pH, color, chemical oxygen demand (COD) and total suspended solids (TSS). Additionally, an activated carbon was added to the samples to reduce residual color after the coagulation-flocculation test. The reduction of color and cod values was greater when more amount of MgCl2 (1.8 g/L) was added. The reduction percentages were ≥90% in the color and >50% for COD. The TSS increased with the addition of MgCl2. Activated carbon removed residual color).Universidad Autónoma del Estado de Méxic

Skinfolds compressibility and digital caliper’s time response in skinfold measurement in male and female young adults

Background: The skinfold caliper reading of the skinfold thickness depends on its dynamic compressibility. This has led to the fact that, while it is indicated that skinfold readings should be taken when the reading is stable, there is no consensus on at what second the reading should be taken after the application of the skinfold caliper. The new Lipowise PRO digital skinfold caliper was used to analyze the evolution of skinfold readings under skinfold caliper pressure. The aim of the present investigation were: a) to analyze the evolution of the reading time of individual skinfolds when subjected to skinfold caliper pressure and when the skinfold reading reaches stability; b) to describe the physical behavior of skinfold tissues' time response to skinfold caliper pressure, and to explore differences between sites and subjects' skinfolds compressibility; and c) to analyze the sex differences in both the reading and the evolution of the skinfold over time. Methods: A descriptive cross-sectional design was followed with a convenience sample of 165 healthy young adults (79 males and 86 females), with eight skinfolds measured using the Lipowise PRO skinfold caliper. The Lipowise PRO skinfold caliper uses a programmable reading time allowing for the measurement of the skinfold's thickness at a rate of 100 times per second, and monitoring skinfold behavior over the 3-second measurement period, thereby enabling the assessment of the tissue response to the constant force exerted by the skinfold caliper jaws. Results: All skinfolds showed statistical differences in terms of compressibility characteristics (p < 0.001). Significant differences were found between measurement time points for individual skinfolds and the sum of skinfolds (p < 0.001-0.025). Stabilization is found depending on the skinfold measured from 1.5 seconds for biceps, subscapular, iliac crest, supraspinal, abdominal, and thigh skinfolds; 2.0 seconds for ∑6 and ∑8 skinfolds; and 2.5 seconds for triceps and calf skinfolds. It was observed an effect of sex on this issue (p < 0.001-0.030). More specifically, in the case of males, the supraspinale and abdominal skinfolds stabilized after 1.5 seconds; the calf skinfold and ∑6 and ∑8 skinfolds stabilized after 2 seconds; while the rest of the skinfolds did not stabilize until 3 seconds. In the case of females, no stabilization of the triceps skinfold was found, while the rest of the individual skinfolds and the ∑6 and ∑8 skinfolds stabilized within 1.5 seconds. A regression analysis indicated that skinfold thickness could be predicted based on measurement time in 50-77% of the cases (p = 0.001). Conclusion: A skinfold caliper application, using the digital caliper Lipowise PRO, three seconds, may be sufficient for achieving stability in the measurement and for obtaining the minimum value for most individuals and the sum of skinfolds. However, there are certain skinfolds that may require more time when performed on certain individuals, which vary according to sex.info:eu-repo/semantics/publishedVersio