Studies of the halogenation of some substituted naphthalenes

A general survey of the reaction of electrophilic halogens with polynuclear aromatic substrates has led to the conclusion that in many cases addition may take place concurrently with substitution. This is important in understanding the mechanism of this kind of reaction, especially as to the sequences leading to the isolated products, which seem to represent an alternative fate of a common carbonium ionic intermediate. The addition of molecular chlorine to a number of simple naphthalene derivatives has, therefore, been investigated under a wide range of experimental conditions. The products of these reactions were isolated and char= acterised as far as possible, particularly by using column chromatography, proton magnetic resonance spectroscopy, and kinetic techniques. The chlorination of 1-, 2-, 1,2-, and 1,4-substitu= ted naphthalenes, with activating, deactivating, or mixed groups on the nucleus, gave products of substitution, accompanied mainly by tetrachlorides and acetoxytrichlo rides, whose structures and predominant conformations in solution have been elucidated. On the whole it is found that addition of chlorine always occurs on the ring to which substitution takes place in accordance with the rules governing electrophilic substitution. Of the six possible orientations of substituents in theresulting tetralin ring system, two forms clearly pre= dominate, having the atoms (or groups) added to the alicyclic ring according to a '-e-e-a' or a'-e-e-e' spatial orientation. The relative rates and products of alkaline dehy= drochlorination have also been studied and are those expected from the configurations of the individual pro= ducts examined, and throw some light on their possible modes of hydrogen chloride elimination.Finally, in discussing the reaction paths leading to the addition products, the results confirm the possibility that polar addition of chlorine can proceed both in the cis- and trans-sense; but, when heterolytic conditions are chosen, the former is a most frequent process that has usually been recognized.<p

Eficacia del nuevo régimen único simplificado bajo la perspectiva del contribuyente tumbesino, año 2022

La presente investigación, realizada con un enfoque de investigación transversal, bajo un estudio de campo y análisis. Para lo cual se aplicó un cuestionario constituido por 7 ítems, con el objetivo de determinar la eficacia del Nuevo Régimen Único Simplificado (NRUS) bajo la perspectiva del contribuyente tumbesino; se estableció una población constituida por 250 usuarios empleándose el muestreo aleatorio para los servicios de orientación, trámites y mesa de partes. El resultado se presenta en cuadros de frecuencia absoluta y porcentual donde arrojan que el NRUS es eficaz, representado con un 99.6% de las respuestas, ubicándose en un nivel alto. Asimismo, se identificó que el 84% cumplen con sus obligaciones en dicho régimen, así como el 99.6% considera que el NRUS tiene una alta viabilidad para los contribuyentes

On the impact of the stem electrical impedance in neural network algorithms for plant monitoring applications

Smart agriculture offers an environmental-friendly path with respect to unsustainable farming that depletes the nutrients in the soil leading to a persistent degradation of ecosystems caused by population growth. Artificial Intelligence (AI) can help mitigate this issue by predicting plant health status to reduce the use of chemicals and optimize water usage. This paper proposes a custom framework to train neural networks and a comparison among different models to point out the impact and the importance of the stem electrical impedance in addition to environmental parameters for plant monitoring applications. In particular, the paper demonstrates how stem electrical impedance improves the accuracy of the proposed neural network application for plant status classification. The data set is composed of electrical impedance spectra and environmental data acquired on four tobacco plants for a two-month-long experiment. In this paper, we describe the acquisition system architecture, the feature composition of the data set, a general overview of the developed framework, and the training of the neural networks showing the different results considering both the stem impedance and the environmental parameters

Unitary representations of U (p,q) and generalized Robinson-Schensted algorithms

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1998.Includes bibliographical references (p. 71-72).Peter Engel Trapa.Ph.D

La producción orgánica artesanal del queso en Ayapamba

The investigation focuses its attention on the analysis of the cost of production of artisanal cheese in the Ayapamba canton of the province of El Oro, for which data is extracted through interviews with the main actors in the production, who are satisfied with know what their cost of generating the products would be and the percentage they are earning from selling their products; The methodology used is descriptive since the processes are clearly detailed in each of the cost elements in order to achieve a greater apprehension among the users of the information; Among the main results, it stands out that the average gross profit margin is 25%, a percentage that allows them to improve the quality of personal life and that of their environment.La investigación centra su atención en el análisis del costo de producción del queso artesanal en el cantón Ayapamba de la provincia de El Oro, para lo cual se extraen datos a través de las entrevistas con los actores principales de la producción, quienes se muestran satisfechos de conocer cuál sería su costo de generar los productos y el porcentaje que están ganando al vender sus productos; la metodología utilizada es la descriptiva ya que se van detallando de manera clara los proceso en cada uno de los elementos del costo con el objeto de lograr una aprehensión mayor dentro de los usuarios de la información; entre os principales resultados se destaca que le promedio de margen de utilidad bruta es del 25%, porcentaje que les permite mejorar la calidad de vida personal y de su entorno

Infection of the malaria mosquito, Anopheles gambiae, with two species of entomopathogenic fungi: effects of concentration, co-formulation, exposure time and persistence

<p>Abstract</p> <p>Background</p> <p>Entomopathogenic fungi <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana </it>isolates have been shown to infect and reduce the survival of mosquito vectors.</p> <p>Methods</p> <p>Here four different bioassays were conducted to study the effect of conidia concentration, co-formulation, exposure time and persistence of the isolates <it>M. anisopliae </it>ICIPE-30 and <it>B. bassiana </it>I93-925 on infection and survival rates of female <it>Anopheles gambiae sensu stricto</it>. Test concentrations and exposure times ranged between 1 × 10⁷- 4 × 10¹⁰conidia m^-2and 15 min - 6 h. In co-formulations, 2 × 10¹⁰conidia m^-2of both fungus isolates were mixed at ratios of 4:1, 2:1, 1:1,1:0, 0:1, 1:2 and 1:4. To determine persistence, mosquitoes were exposed to surfaces treated 1, 14 or 28 d previously, with conidia concentrations of 2 × 10⁹, 2 × 10¹⁰or 4 × 10¹⁰.</p> <p>Results</p> <p>Mosquito survival varied with conidia concentration; 2 × 10¹⁰conidia m^-2was the concentration above which no further reductions in survival were detectable for both isolates of fungus. The survival of mosquitoes exposed to single and co-formulated treatments was similar and no synergistic or additive effects were observed. Mosquitoes were infected within 30 min and longer exposure times did not result in a more rapid killing effect. Fifteen min exposure still achieved considerable mortality rates (100% mortality by 14 d) of mosquitoes, but at lower speed than with 30 min exposure (100% mortality by 9 d). Conidia remained infective up to 28 d post-application but higher concentrations did not increase persistence.</p> <p>Conclusion</p> <p>Both fungus isolates are effective and persistent at low concentrations and short exposure times.</p

Functional Changes in the Snail Statocyst System Elicited by Microgravity

BACKGROUND: The mollusk statocyst is a mechanosensing organ detecting the animal's orientation with respect to gravity. This system has clear similarities to its vertebrate counterparts: a weight-lending mass, an epithelial layer containing small supporting cells and the large sensory hair cells, and an output eliciting compensatory body reflexes to perturbations. METHODOLOGY/PRINCIPAL FINDINGS: In terrestrial gastropod snail we studied the impact of 16- (Foton M-2) and 12-day (Foton M-3) exposure to microgravity in unmanned orbital missions on: (i) the whole animal behavior (Helix lucorum L.), (ii) the statoreceptor responses to tilt in an isolated neural preparation (Helix lucorum L.), and (iii) the differential expression of the Helix pedal peptide (HPep) and the tetrapeptide FMRFamide genes in neural structures (Helix aspersa L.). Experiments were performed 13-42 hours after return to Earth. Latency of body re-orientation to sudden 90° head-down pitch was significantly reduced in postflight snails indicating an enhanced negative gravitaxis response. Statoreceptor responses to tilt in postflight snails were independent of motion direction, in contrast to a directional preference observed in control animals. Positive relation between tilt velocity and firing rate was observed in both control and postflight snails, but the response magnitude was significantly larger in postflight snails indicating an enhanced sensitivity to acceleration. A significant increase in mRNA expression of the gene encoding HPep, a peptide linked to ciliary beating, in statoreceptors was observed in postflight snails; no differential expression of the gene encoding FMRFamide, a possible neurotransmission modulator, was observed. CONCLUSIONS/SIGNIFICANCE: Upregulation of statocyst function in snails following microgravity exposure parallels that observed in vertebrates suggesting fundamental principles underlie gravi-sensing and the organism's ability to adapt to gravity changes. This simple animal model offers the possibility to describe general subcellular mechanisms of nervous system's response to conditions on Earth and in space

Microglia Are Mediators of Borrelia burgdorferi–Induced Apoptosis in SH-SY5Y Neuronal Cells

Inflammation has long been implicated as a contributor to pathogenesis in many CNS illnesses, including Lyme neuroborreliosis. Borrelia burgdorferi is the spirochete that causes Lyme disease and it is known to potently induce the production of inflammatory mediators in a variety of cells. In experiments where B. burgdorferi was co-cultured in vitro with primary microglia, we observed robust expression and release of IL-6 and IL-8, CCL2 (MCP-1), CCL3 (MIP-1α), CCL4 (MIP-1β) and CCL5 (RANTES), but we detected no induction of microglial apoptosis. In contrast, SH-SY5Y (SY) neuroblastoma cells co-cultured with B. burgdorferi expressed negligible amounts of inflammatory mediators and also remained resistant to apoptosis. When SY cells were co-cultured with microglia and B. burgdorferi, significant neuronal apoptosis consistently occurred. Confocal microscopy imaging of these cell cultures stained for apoptosis and with cell type-specific markers confirmed that it was predominantly the SY cells that were dying. Microarray analysis demonstrated an intense microglia-mediated inflammatory response to B. burgdorferi including up-regulation in gene transcripts for TLR-2 and NFκβ. Surprisingly, a pathway that exhibited profound changes in regard to inflammatory signaling was triggering receptor expressed on myeloid cells-1 (TREM1). Significant transcript alterations in essential p53 pathway genes also occurred in SY cells cultured in the presence of microglia and B. burgdorferi, which indicated a shift from cell survival to preparation for apoptosis when compared to SY cells cultured in the presence of B. burgdorferi alone. Taken together, these findings indicate that B. burgdorferi is not directly toxic to SY cells; rather, these cells become distressed and die in the inflammatory surroundings generated by microglia through a bystander effect. If, as we hypothesized, neuronal apoptosis is the key pathogenic event in Lyme neuroborreliosis, then targeting microglial responses may be a significant therapeutic approach for the treatment of this form of Lyme disease