Modelling performance by continents in swimming.

Introduction: There is a growing interest in the scientific community about the progression and congruity in the performance of talented participants who complete representing different nations in the most important international events. The prediction of incoming performances is nowadays in demand with the objective of returning in talent investment. Talent identification programs have tried to select and develop sports talent over years. However, to our knowledge, there is a lack of research about success in swimming World Championships (WCs) performance considering continents-country and how successful outcomes are influenced by these variables. Therefore, the primary goal is to analyze the effect of early specialization comparing the performance progression model of the countries gathered by continents. Methods: Participant's data from all Junior and Senior WCs between 2006 and 2017 from International Swimming Federation (FINA). One-way ANOVA, ANCOVA and regression model were used to explain whether the variable category, age, best z-score, experience, and continent influences the performance obtained in Absolute WC. Results: Significant differences (p < 0.01) were found between the average performance obtained by the two different categories (junior: swimmers participating in junior WCs before senior WCs; senior: swimmers participating in senior WCs without previous participation in junior WCs), where swimmers from category junior showed significant better performance's times than seniors, except in America. ANCOVA results showed that generally, the greatest differences where in the earliest ages, with best performance registered in category junior in all the continents. Also, the experience was a significant variable in the general model. Conclusion: Swimmers who had participated in junior category prior absolute obtained better performance's times than those swimmers who participated directly in absolute, in the first participation in senior WC. Thus, early specialization is a key factor to obtain better results in senior WCs for all the continents, except in America.

Disfunción apical transitoria o síndrome de Takotsubo: reporte de un caso / Transient apical ballooning or Takotsubo cardiomyopathy: case report

INTRODUCCIÓN: El Síndrome de Takotsubo (STT), balonamiento apical o síndrome del corazón roto es una patología que produce un aturdimiento agudo del miocardio sin encontrarse lesiones obstructivas significativas a la coronariografía. Epidemiologicamente hay mayor incidencia en mujeres postmenopáusicas. Su patogenia es desconocida, con múltiples teorías propuestas. PRESENTACIÓN DEL CASO: Paciente sexo femenino de 41 años, sin antecedentes mórbidos. Encontrándose en reposo, refiere dolor opresivo retroesternal severo irradiado a ambas extremidades superiores con signos y síntomas neurovegetativos intensos, sin presencia de alteraciones emocionales o factores de estrés relacionados. Es trasladada a consultorio de Neltume, zona rural de la región de los Ríos, donde electrocardiograma sugiere infarto agudo al miocardio con supradesnivel del segmento ST de pared inferior y anterior. Es derivada a su hospital base donde por mejoría clínica, se realiza electrocardiograma de control a cinco horas del inicio, mostrando criterios de reperfusión espontánea. Se realiza coronariografía para evaluación, que objetiva arterias coronarias sin lesiones obstructivas y ventriculografía que muestra disquinesia apical compatible con STT. Se deriva a hospital Naval de Talcahuano donde la paciente evoluciona favorablemente, objetivándose por ecocardiografía una restauración de la función cardíaca normal. La paciente es dada de alta tras siete días de tratamiento médico para síndrome coronario agudo. DISCUSIÓN: Como diagnóstico diferencial de síndrome coronario agudo, la sospecha diagnóstica precoz y el acceso a imagenología cardiaca permiten confirmar el síndrome. El manejo de estos pacientes es conservador, con seguimiento imagenológico por posibles complicaciones hasta la recuperación espontánea del funcionamiento ventricular.

INTRODUCTION: TakoTsubo Cardiomyopathy (TCM), transient apical ballooning o broken heart syndrome is a transient cardiac syndrome most commonly presented after severe emotional or physical stress, producing acute myocardial dysfunction, without significant coronary stenosis. Its pathogenesis is unknown, with multiple proposed theories and a higher incidence in postmenopausal women. CASE REPORT: 41-year-old female with no relevant medical history. While resting at home, she presented a severe episode of retrosternal pain, irradiated to both arms and associated with adrenergic symptoms, without related emotional or stressful factors. Twenty minutes after onset, she was brought to a primary care facility in Neltume, Los Rios Region, where electrocardiogram (EKG) showed STsegment elevation on inferior and anterior leads. She was then transferred to the referral center, where after five hours of the beginning of symptoms, follow-up EKG showed spontaneous reperfusion criteria, correlated with spontaneous resolution of symptoms during transferring. Coronary angiography showed no significant stenosis and ventriculography confirmed apical ballooning compatible with TCM. The patient was referred to the Naval Hospital of Talcahuano, where she improved clinically, being discharged seven days later with standard treatment for acute coronary syndrome. DISCUSSION: As part of the differential diagnosis of acute coronary syndrome, early suspicion and access to cardiac catheterization provides the basis for confirming the diagnosis. Treatment is mainly conservative, with imaging follow-up for possible complications until recovery of the ventricular function.

Preparation of new monoanionic "scorpionate" ligands: synthesis and structural characterization of titanium(IV) complexes bearing this class of ligand.

The preparation of new "scorpionate" ligands in the form of the lithium derivatives [(Li(bdmpzdta)(H(2)O))(4)] (1) [bdmpzdta = bis(3,5-dimethylpyrazol-1-yl)dithioacetate], [Li(bdphpza)(H(2)O)(THF)] (2) [bdphpza = bis(3,5-diphenylpyrazol-1-yl)acetate], and [Li(bdphpzdta)(H(2)O)(THF)] (3) [bdphpzdta = bis(3,5-diphenylpyrazol-1-yl)dithioacetate] has been carried out. Furthermore, a series of titanium complexes has been prepared by reaction of TiCl(4)(THF)(2) with the lithium reagents [(Li(bdmpza)(H(2)O))(4)] (4) [bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate] and 1. Under the appropriate experimental conditions neutral complexes, namely [TiCl(3)(kappa(3)-bdmpza)] (5), [TiCl(3)(kappa(3)-bdmpzdta)] (6), and [TiCl(2)(kappa(2)-bdmpzdta)(2)] (7), and cationic complexes, namely [TiCl(2)(THF)(kappa(3)-bdmpza)]Cl (8) and [TiCl(2)(THF)(kappa(3)-bdmpzdta)]Cl (9), were isolated. Complexes 8 and 9 undergo an interesting nucleophilic THF ring-opening reaction to give the corresponding alkoxide-containing species [TiCl(2)(kappa(3)-bdmpza)(O(CH(2))(4)Cl)] (10) and [TiCl(2)(kappa(3)-bdmpzdta)(O(CH(2))(4)Cl)] (11). A family of alkoxide-containing complexes of general formulas [TiCl(2)(kappa(3)-bdmpza)(OR)] [R = Me (12); R = Et (14); R = (i)Pr (16); R = (t)Bu (18)] and [TiCl(2)(kappa(3)-bdmpzdta)(OR)] [R = Me (13); R = Et (15); R = (i)Pr (17)] was also prepared. The structures of these complexes have been determined by spectroscopic methods, and in addition, the X-ray crystal structures of 3, 7, 10, and 11 were also established.

Supported metallocene catalysts by surface organometallic chemistry. Synthesis, characterization, and reactivity in ethylene polymerization of oxide-supported mono- and biscyclopentadienyl zirconium alkyl complexes: establishment of structure/reactivity relationships.

The reactions of CpZr(CH(3))(3), 1, and Cp(2)Zr(CH(3))(2), 2, with partially dehydroxylated silica, silica-alumina, and alumina surfaces have been carried out with careful identification of the resulting surface organometallic complexes in order to probe the relationship between catalyst structure and polymerization activity. The characterization of the supported complexes has been achieved in most cases by in situ infrared spectroscopy, surface microanalysis, qualitative and quantitative analysis of evolved gases during surface reactions with labeled surface, solid state (1)H and (13)C NMR using (13)C-enriched compounds, and EXAFS. 1 and 2 react with silica(500) and silica-alumina(500) by simple protonolysis of one Zr-Me bond by surface silanols with formation of a single well-defined neutral compound. In the case of silica-alumina, a fraction of the supported complexes exhibits some interactions with electronically unsaturated surface aluminum sites. 1 and 2 also react with the hydroxyl groups of gamma-alumina(500), leading to several surface structures. Correlation between EXAFS and (13)C NMR data suggests, in short, two main surface structures having different environments for the methyl group: [Al](3)-OZrCp(CH(3))(2) and [Al](2)-OZrCp(CH(3))(mu-CH(3))-[Al] for the monoCp series and [Al](2)-OZrCp(2)(CH(3)) and [Al]-OZrCp(2)(mu-CH(3))-[Al] for the bisCp series. Ethylene polymerization has been carried out with all the supported complexes under various reaction conditions. Silica-supported catalysts in the absence of any cocatalyst exhibited no activity whatsoever for ethylene polymerization. When the oxide contained Lewis acidic sites, the resulting surface species were active. The activity, although improved by the presence of additional cocatalysts, remained very low by comparison with that of the homogeneous metallocene systems. This trend has been interpreted on the basis of various possible parameters, including the (p-pi)-(d-pi) back-donation of surface oxygen atoms to the zirconium center.