Neutrinos and Nucleosynthesis in Supernova

The type II supernova is considered as a candidate site for the production of heavy elements. The nucleosynthesis occurs in an intense neutrino flux, we calculate the electron fraction in this environment.Comment: RevTex4 style, 3 pages including 1 figure. Presented at Mexican School of Astrophysics 2002, Guanajuato, Mexico, 31 Jul - 7 Aug 2002. Final version to appear in the Proceedings of IX Mexican Workshop on Particles and Fields Physics Beyond the Standard Model, Colima Col. Mexico, November 17-22, 200

Engineering professors' conceptions on basic topics of electromagnetism in Mexico

Electromagnetism is one of the introductory physics subjects common to many engineering programs in Mexico and other countries. There are several studies about students’ misconceptions regarding the contents of electromagnetism courses but the information about teachers’ misconceptions which is one of the main factors that contribute to students’ misconceptions, is not very extensive. It is a fact that teachers, as well as students, have problems with the scientific knowledge of some concepts (Pardhan & Bano, 2001). Since they are responsible for helping students to fully understand and give a proper meaning to these concepts, it is very important to find out what teachers know about these concepts, to generate teacher formation programs that help them in the improvement of their teaching activities. Moreover, most of the existing studies focus on identifying misconceptions about the properties of electric charges (Furió-Mas & Guisasola Aranzabal, 2008), electric field, Gauss’s law, electric current (Hashish et al., 2020) and voltage, but none of them is centered around the basic concepts in electrostatics and the strong relations between them. This work is part of a qualitative research with a descriptive design and presents the results of a 2-tier instrument combined with a semi-structured interview, designed to identify the conceptions that in-service engineering teachers have about the concepts of electrostatic force, electric field, electric potential, and the relation between them, distinguishing between correct conceptions, misconceptions, and lack of knowledge. RESULTS Information about the teachers’ academic training and teaching experience will be presented, correlating this information to the conceptions that teachers have about the basic electrostatics concepts. Due to the academic training and teaching experience that in-service teachers have, predominance of misconceptions over lack of knowledge is expected. REFERENCES Furió-Mas, C., & Guisasola Aranzabal, J. (2008). Dificultades de aprendizaje de los conceptos de carga y de campo eléctrico en estudiantes de bachillerato y universidad. Enseñanza de Las Ciencias. Revista de Investigación y Experiencias Didácticas, 16(1), 131–146. https://doi.org/10.5565/rev/ensciencias.4148. Hashish, A. H., Seyd-Darwish, I., & Tit, N. (2020). Addressing Some Physical Misconceptions in Electrostatics of Freshman Engineering Students. International Journal for Innovation Education and Research, 8(2), 01–07. https://doi.org/10.31686/ijier.vol8.iss2.2161. Pardhan, H., & Bano, Y. (2001). Science teachers’ alternate conceptions about direct-currents. International Journal of Science Education, 23(3), 301–318. https://doi.org/10.1080/095006901750066538

On the growth of perturbations in interacting dark energy and dark matter fluids

The covariant generalizations of the background dark sector coupling suggested in G. Mangano, G. Miele and V. Pettorino, Mod. Phys. Lett. A 18, 831 (2003) are considered. The evolution of perturbations is studied with detailed attention to interaction rate that is proportional to the product of dark matter and dark energy densities. It is shown that some classes of models with coupling of this type do not suffer from early time instabilities in strong coupling regime.Comment: 11 pages, 2 figures. v3: minor changes, typos fixe

Transformação de algodão (Gossypium Hirsutum L.) através do uso de policátion.

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Specific label-free and real-time detection of oxidized low density lipoprotein (oxLDL) using an immunosensor with three monoclonal antibodies

Increased levels of plasma oxLDL, which is the oxidized fraction of Low Density Lipoprotein (LDL), are associated with atherosclerosis, an inflammatory disease, and the subsequent development of severe cardiovascular diseases that are today a major cause of death in modern countries. It is therefore important to find a reliable and fast assay to determine oxLDL in serum. A new immunosensor employing three monoclonal antibodies (mAbs) against oxLDL is proposed in this work as a quick and effective way to monitor oxLDL. The oxLDL was first employed to produce anti-oxLDL monoclonal antibodies by hybridoma cells that were previously obtained. The immunosensor was set-up by selfassembling cysteamine (Cyst) on a gold (Au) layer (4 mm diameter) of a disposable screen-printed electrode. Three mAbs were allowed to react with N-hydroxysuccinimide (NHS) and ethyl(dimethylaminopropyl)carbodiimide (EDAC), and subsequently incubated in the Au/Cys. Albumin from bovine serum (BSA) was immobilized further to ensure that other molecules apart from oxLDL could not bind to the electrode surface. All steps were followed by various characterization techniques such as electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV). The analytical operation of the immunosensor was obtained by incubating the sensing layer of the device in oxLDL for 15 minutes, prior to EIS and SWV. This was done by using standard oxLDL solutions prepared in foetal calf serum, in order to simulate patient's plasma with circulating oxLDL. A sensitive response was observed from 0.5 to 18.0 mg mL 1 . The device was successfully applied to determine the oxLDL fraction in real serum, without prior dilution or necessary chemical treatment. The use of multiple monoclonal antibodies on a biosensing platform seemed to be a successful approach to produce a specific response towards a complex multi-analyte target, correlating well with the level of oxLDL within atherosclerosis disease, in a simple, fast and cheap way

Water Quality of Cisterns and Underground Dams in Semiarid Regions: Case Study of Afogados da Ingazeira, Pernambuco – Northeast Brazil

In semiarid regions water resources are limited and irregularly distributed over space and time. As a result, water scarcity is a reality emphasized by the high evaporation rate recorded in these regions (2000 mm per year). In consequence, the management of water use is a subject that requires priority, especially in the regions where water is a scarce resource. There should be orientation towards its rational use through storage in appropriate places – as cisterns, and underground dams. Additionally, these techniques represent an advantage since they have low costs and can be developed and maintained by individual or community programmes. The social mobilization that occurs with families involved on the construction and maintenance of these structures guaranty the sustainability of these techniques. Although several local populations continued to use water without any treatment, is essential to promote the sanitary security of those waters, which must achieve the human consumption standards, defined on Brazilian legislations. The main goals of this work are: (i) to analyze the maintenance of these structures and the facilities of their implementation; (ii) to calculate the costs involved; (iii) and finally to discuss the importance of improve water quality in cisterns and groundwater dams

Experimental and numerical vibration correlation of pre-stressed laminated reinforced panel

This research work deals with the buckling load prediction of reinforced laminated composite panels of aeronautical interest. Being subjected to pure compression, these panels are characterized by stable post-buckling. Thus, the vibration correlation technique (VCT) is utilized herein as an effective nondestructive means to extrapolate critical loads from free vibration measurements. A hierarchical design of experiments, making use of nested multifactors (i.e. panel replicas, test setups, and measurement repetitions), is employed to estimate components of variance. The experimental outcomes are compared with the results of an advanced finite element model with layer-wise kinematics and based on the Carrera Unified Formulation (CUF). The results show that, although obtained with a low number of tests and specimens, the VCT experiments are repeatable and provide a good validation of the numerical simulations, which are demonstrated to be accurate and reliable

Increasing Dominance - the Role of Advertising, Pricing and Product Design

Despite the empirical relevance of advertising strategies in concentrated markets, the economics literature is largely silent on the effect of persuasive advertising strategies on pricing, market structure and increasing (or decreasing) dominance. In a simple model of persuasive advertising and pricing with differentiated goods, we analyze the interdependencies between ex-ante asymmetries in consumer appeal, advertising and prices. Products with larger initial appeal to consumers will be advertised more heavily but priced at a higher level - that is, advertising and price discounts are strategic substitutes for products with asymmetric initial appeal. We find that the escalating effect of advertising dominates the moderating effect of pricing so that post-competition market shares are more asymmetric than pre-competition differences in consumer appeal. We further find that collusive advertising (but competitive pricing) generates the same market outcomes, and that network effects lead to even more extreme market outcomes, both directly and via the effect on advertising