Central Composite Design to Optimizate the Derivatization Procedure for Analysis of Biogenic Amines by HPLC-UV

A simple benzoylation procedure was optimized for the biogenic amines derivatization prior to high-performance liquid chromatography determination. The significant factors affecting biogenic amine benzoylation yield were optimized by central composite design (CCD). The obtained optimal conditions resulted in a chromatographic peaks area increase with fewer interferences. Moreover, the efficiency parameters for chromatographic separation of putrescine, histamine and tyramine were determined under optimum operating conditions, which included: capacity factors or retention (k’) = 2.5-4.2, selectivity factors (α) > 1 and resolution values (Rs) > 1.5, indicating that the column provided good separation of the analytes. The optimized method was applied in spiked fish samples with standard solutions of putrescine, histamine and tyramine at concentrations of 50, 80 and 50 mg L-1, respectively, to achieve recovery rates in a range from 90.89 to 96.65% for putrescine; 93.36 to 95.87% for histamine; 86.57 to 93.33% for tyramine, with the relative standard deviation (RSD) less than 4%

The electrical double layer for a fully asymmetric electrolyte around a spherical colloid: an integral equation study

The hypernetted chain/mean spherical approximation (HNC/MSA) integral equation is obtained and solved numerically for a totally asymmetric primitive model electrolyte around a spherical macroparticle. The ensuing radial distribution functions show a very good agreement when compared to our Monte Carlo and molecular dynamics simulations for spherical geometry and with respect to previous anisotropic reference HNC calculations in the planar limit. We report an analysis of the potential vs charge relationship, radial distribution functions, mean electrostatic potential and cumulative reduced charge for representative cases of 1:1 and 2:2 salts with a size asymmetry ratio of 2. Our results are collated with those of the Modified Gouy-Chapman (MGC) and unequal radius Modified Gouy-Chapman (URMGC) theories and with those of HNC/MSA in the restricted primitive model (RPM) to assess the importance of size asymmetry effects. One of the most striking characteristics found is that,\textit{contrary to the general belief}, away from the point of zero charge the properties of an asymmetric electrical double layer (EDL) are not those corresponding to a symmetric electrolyte with the size and charge of the counterion, i.e. \textit{counterions do not always dominate}. This behavior suggests the existence of a new phenomenology in the EDL that genuinely belongs to a more realistic size-asymmetric model where steric correlations are taken into account consistently. Such novel features can not be described by traditional mean field theories like MGC, URMGC or even by enhanced formalisms, like HNC/MSA, if they are based on the RPM.Comment: 29 pages, 13 figure

Jornadas escolares complementarias en la Institucion Educativa Moreno y Escand?n del Municipio de Mariquita

37 p. Recurso Electr?nicoEl presente informe final se deriva de la Investigaci?n Evaluativa del Programa Jornada Escolar Complementaria Ejecutado por La Caja de Compensaci?n Familiar del Tolima Comfenalco, cuyo prop?sito principal consist?a en identificar la trayectoria educativa de los estudiantes beneficiarios del Programa Jornada Escolar Complementaria, en el municipio de Mariquita Tolima, instituci?n educativa Moreno y Escand?n. La trayectoria educativa est? referida a los cambios percibidos con relaci?n a: identidad, participaci?n, convivencia, respeto, al acatamiento de normas y confianza. Tambi?n se busc? identificar los cambios percibidos en el rendimiento acad?mico los cuales se atribuyen a la participaci?n en el programa. Se seleccion? la instituci?n Educativa Moreno y Escand?n, debido a que en ella se perciben las necesidades de este acompa?amiento y de la ejecuci?n de las Jornadas Complementarias por cuanto se desea mejorar los aspectos acad?micos, disciplinarios y de convivencia comentados anteriormente. La importancia de esta investigaci?n radica en que se pone de manifiesto una experiencia exitosa entre el sector educativo y las Cajas de Compensaci?n Familiar que brindan un acompa?amiento importante en la formaci?n de los educandos, como instrumentos para recolecci?n de informaci?n se utiliz? las reuniones de padres de familia quienes comentaron los aspectos positivos que se evidenciaron en sus hijos en el desarrollo de las jornadas complementarias, por medio de un proceso participativo que involucr? los beneficiarios del Programa, como son los estudiantes, padres de familia y comunidad educativa. Esta investigaci?n arrojar? luces respecto a la influencia de las jornadas complementarias en los estudiantes y por ser la primera en su tipo en el Departamento del Tolima, permitir? que se abra una nueva l?nea de investigaci?n al respecto de este tema tan interesante.This final report is derived from the Evaluative Investigation of the Complementary School Day Program implemented by the Tolima Comfenalco Family Compensation Fund, whose main purpose was to identify the educational trajectory of the beneficiary students of the Complementary School Day Program in the municipality of Mariquita Tolima, educational institution Moreno and Escand?n. The educational trajectory refers to the changes perceived in relation to: identity, participation, coexistence, respect, compliance with norms and trust. It was also sought to identify perceived changes in academic performance which are attributed to participation in the program. The Educational Institution Moreno and Escand?n was selected, because it perceives the needs of this accompaniment and the implementation of the Complementary Days in order to improve the academic, disciplinary and coexistence aspects discussed above. The importance of this research is that it shows a successful experience between the education sector and the Family Compensation Funds that provide important accompaniment in the education of the students, as instruments for gathering information was used the meetings of parents of Family who commented on the positive aspects that were evidenced in their children in the development of the complementary days, through a participatory process that involved the beneficiaries of the Program, such as students, parents and educational community. This research will shed light on the influence of the complementary days on students and being the first of its kind in the Department of Tolima, will allow a new line of research to be opened regarding this interesting topic. Keywords: education, school day, accompaniment, research

A Primer On International Environmental Law: Sustainability As A Principle Of International Law And Custom

International environmental law draws from two important sources: international treaties and conventions\u27 and customary international law

Ion pairing in model electrolytes: A study via three particle correlation functions

A novel integral equations approach is applied for studying ion pairing in the restricted primitive model (RPM) electrolyte, i. e., the three point extension (TPE) to the Ornstein-Zernike integral equations. In the TPE approach, the three-particle correlation functions $g^{[3]}({\bf r}_{1},{\bf r}_{2},{\bf r}_{3})$ are obtained. The TPE results are compared to molecular dynamics (MD) simulations and other theories. Good agreement between TPE and MD is observed for a wide range of parameters, particularly where standard integral equations theories fail, i. e., low salt concentration and high ionic valence. Our results support the formation of ion pairs and aligned ion complexes.Comment: 43 pages (including 18 EPS figs) - RevTeX 4 - J. Chem. Phys. (in press

Vortices on demand in multicomponent Bose-Einstein condensates

We present a simple mechanism to produce vortices at any desired spatial locations in harmonically trapped Bose-Einstein condensates (BEC) with multicomponent spin states coupled to external transverse and axial magnetic fields. The vortices appear at the spatial points where the spin-transverse field interaction vanishes and, depending on the multipolar magnetic field order, the vortices can acquire different predictable topological charges. We explicitly demonstrate our findings, both numerically and analytically, by analyzing a 2D BEC via the Gross-Pitaevskii equation for atomic systems with either two or three internal states. We further show that, by an spontaneous symmetry breaking mechanism, vortices can appear in any spin component, unless symmetry is externally broken at the outset by an axial field. We suggest that this scenario may be tested using an ultracold gas of $^{87}$Rb occupying all three $F = 1$ states in an optical trap.Comment: 11 pages, 9 figures, (Accepted in PRA

Advantages and Disadvantages of Traditional Abaca, Genetically Modified Abaca, and Cross Hybrid Abaca

Abaca (Musa Textilis Née), also known as Manila hemp, is a plant native to the Philippines, which expanded through different parts of Asia. It is a biodegradable and sustainable source of fiber known for its high quality. Due to viruses, poor government support, and lack of fundings, the abaca fiber industry is encountering obstacles in keeping up with the global demands. Over time, researchers developed new abaca types such as crossbred abaca and genetically modified abaca to solve these problems, but these have their own deficiencies as well. The purpose of the study was to identify, assess, and elaborate on the advantages and disadvantages of each of the abaca types. This was accomplished through the evaluation of literature and the collection of data in interviews. The study was a systematic review focusing on meta-synthesis, with information derived from previously published research or related literature and information from experts in the field. It was determined that traditional abaca is vastly preferred over genetically modified abaca and cross hybrid abaca, due to a number of reasons, including lack of research and economic viability. Traditional abaca was found to be more sustainable overall. It was recommended that traditional abaca should be promoted more to spread awareness, and that farmers should be educated regarding the proper process of caring for abaca plants. Stigma regarding cross hybrid and genetically modified abaca should be addressed as well

Fossil group origins - VI. Global X-ray scaling relations of fossil galaxy clusters

We present the first pointed X-ray observations of 10 candidate fossil galaxy groups and clusters. With these Suzaku observations, we determine global temperatures and bolometric X-ray luminosities of the intracluster medium (ICM) out to $r_{500}$ for six systems in our sample. The remaining four systems show signs of significant contamination from non-ICM sources. For the six objects with successfully determined $r_{500}$ properties, we measure global temperatures in the range $2.8 \leq T_{\mathrm{X}} \leq 5.3 \ \mathrm{keV}$, bolometric X-ray luminosities of $0.8 \times 10^{44} \ \leq L_{\mathrm{X,bol}} \leq 7.7\times 10^{44} \ \mathrm{erg} \ \mathrm{s}^{-1}$, and estimate masses, as derived from $T_{\mathrm{X}}$, of $M_{500} > 10^{14} \ \mathrm{M}_{\odot}$. Fossil cluster scaling relations are constructed for a sample that combines our Suzaku observed fossils with fossils in the literature. Using measurements of global X-ray luminosity, temperature, optical luminosity, and velocity dispersion, scaling relations for the fossil sample are then compared with a control sample of non-fossil systems. We find the fits of our fossil cluster scaling relations are consistent with the relations for normal groups and clusters, indicating fossil clusters have global ICM X-ray properties similar to those of comparable mass non-fossil systems.Comment: 17 pages, 7 figures, 8 tables. Accepted for publication in MNRA

Electrophoresis of a rod macroion under polyelectrolyte salt: Is mobility reversed for DNA?

By molecular dynamics simulation, we study the charge inversion phenomenon of a rod macroion in the presence of polyelectrolyte counterions. We simulate electrophoresis of the macroion under an applied electric field. When both counterions and coions are polyelectrolytes, charge inversion occurs if the line charge density of the counterions is larger than that of the coions. For the macroion of surface charge density equal to that of the DNA, the reversed mobility is realized either with adsorption of the multivalent counterion polyelectrolyte or the combination of electrostatics and other mechanisms including the short-range attraction potential or the mechanical twining of polyelectrolyte around the rod axis.Comment: 8 pages, 5 figures, Applied Statistical Physics of Molecular Engineering (Mexico, 2003). Journal of Physics: Condensed Matters, in press (2004). Journal of Physics: Condensed Matters, in press (2004