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Objective: To identify urinary catheter (UC)-associated urinary tract infection (CAUTI) incidence and risk factors. Design: A prospective cohort study. Setting: The study was conducted across 623 ICUs of 224 hospitals in 114 cities in 37 African, Asian, Eastern European, Latin American, and Middle Eastern countries. Participants: The study included 169,036 patients, hospitalized for 1,166,593 patient days. Methods: Data collection took place from January 1, 2014, to February 12, 2022. We identified CAUTI rates per 1,000 UC days and UC device utilization (DU) ratios stratified by country, by ICU type, by facility ownership type, by World Bank country classification by income level, and by UC type. To estimate CAUTI risk factors, we analyzed 11 variables using multiple logistic regression. Results: Participant patients acquired 2,010 CAUTIs. The pooled CAUTI rate was 2.83 per 1,000 UC days. The highest CAUTI rate was associated with the use of suprapubic catheters (3.93 CAUTIs per 1,000 UC days); with patients hospitalized in Eastern Europe (14.03) and in Asia (6.28); with patients hospitalized in trauma (7.97), neurologic (6.28), and neurosurgical ICUs (4.95); with patients hospitalized in lower-middle-income countries (3.05); and with patients in public hospitals (5.89). The following variables were independently associated with CAUTI: Age (adjusted odds ratio [aOR], 1.01; P <.0001), female sex (aOR, 1.39; P <.0001), length of stay (LOS) before CAUTI-acquisition (aOR, 1.05; P <.0001), UC DU ratio (aOR, 1.09; P <.0001), public facilities (aOR, 2.24; P <.0001), and neurologic ICUs (aOR, 11.49; P <.0001). Conclusions: CAUTI rates are higher in patients with suprapubic catheters, in middle-income countries, in public hospitals, in trauma and neurologic ICUs, and in Eastern European and Asian facilities. Based on findings regarding risk factors for CAUTI, focus on reducing LOS and UC utilization is warranted, as well as implementing evidence-based CAUTI-prevention recomm

Here, m-order methods are developed that conserve the form of the first-order methods. The m-order methods have a higher rate of convergence than their first-order version. These m-order methods are subsequences of its precursor method, where some benefits of using vector and parallel processors can be explored. The numerical results obtained with vector implementations show computational advantages when compared to the first-order versions., Aqui, são desenvolvidos métodos de ordem m que conservam a forma dos métodos de primeiraordem. Métodos de ordem m têm uma taxa de convergência maior que sua versão de primeira ordem.Esses métodos de ordem m são subsequências de seu método precursor, onde alguns benefícios do usode processadores vetoriais e paralelos podem ser explorados. Os resultados numéricos obtidos com asimplementações vetoriais mostram vantagens computacionais quando comparadas as versões deprimeira ordem.

Here, m-order methods are developed that conserve the form of the first-order methods. The m-order methods have a higher rate of convergence than their first-order version. These m-order methods are subsequences of its precursor method, where some benefits of using vector and parallel processors can be explored. The numerical results obtained with vector implementations show computational advantages when compared to the first-order versions., Aqui, são desenvolvidos métodos de ordem m que conservam a forma dos métodos de primeiraordem. Métodos de ordem m têm uma taxa de convergência maior que sua versão de primeira ordem.Esses métodos de ordem m são subsequências de seu método precursor, onde alguns benefícios do usode processadores vetoriais e paralelos podem ser explorados. Os resultados numéricos obtidos com asimplementações vetoriais mostram vantagens computacionais quando comparadas as versões deprimeira ordem.

Here, m-order methods are developed that conserve the form of the first-order methods. The m-order methods have a higher rate of convergence than their first-order version. These m-order methods are subsequences of its precursor method, where some benefits of using vector and parallel processors can be explored. The numerical results obtained with vector implementations show computational advantages when compared to the first-order versions., Aqui, são desenvolvidos métodos de ordem m que conservam a forma dos métodos de primeiraordem. Métodos de ordem m têm uma taxa de convergência maior que sua versão de primeira ordem.Esses métodos de ordem m são subsequências de seu método precursor, onde alguns benefícios do usode processadores vetoriais e paralelos podem ser explorados. Os resultados numéricos obtidos com asimplementações vetoriais mostram vantagens computacionais quando comparadas as versões deprimeira ordem.

The Analytic Hierarchy Process (AHP) is a decision making method, which has as its greatestcriticism the rank reversal effect. A new mathematical analysis of this method is performed in 22 applications.Two formulations of the AHP show to be equivalent in solution and behavior in the sensitivityanalysis. The sensitivity analysis carried out includes a standard part using the critical element, andtwo new analyzes using the critical column vector and condition number. In some cases, AHP is moresensitive to perturbations in the critical column vector than to perturbations in the critical element. Thecritical column vector is unique independently of whether the perturbation is relative orabsolute. Thesensitivity analysis using the condition number reveals that the rank reversal will always exist for everylinear method. Algebraic transformations for deficient rank matrix are performed to obtain a more stableand reliable method., O Analytic Hierarchy Process (AHP) é um método de apoio à decisão tendo como uma das maiores críticas o efeito de reversão de ranking. Uma nova análise matemática deste método é realizada em 22 aplicações. Duas formulações do AHP mostram-se equivalentes em solução e comportamento na análise de sensibilidade. A análise de sensibilidade realizada inclui uma parte típica usando o elemento crítico e duas novas análises usando o vetor coluna crítica e o número de condicionamento. Em alguns casos, o AHP é mais sensível a perturbações no vetor coluna crítico do que a perturbações no elemento crítico. O vetor coluna crítico é único, independentemente da perturbação ser relativa ou absoluta. A análise de sensibilidade usando o número de condicionamento revela que a reversão de ranking sempre existirá para todo método linear. Transformações algébricas para matrizes com posto incompleto são realizadas para obter um método mais estável e confiável.Palavras chave: Análise múltiple critérios, análise de decisão, reversão de ranking, sistemas lineares de equações, análise de sensibilidade, tomada de decisão.

The Analytic Hierarchy Process (AHP) is a decision making method, which has as its greatestcriticism the rank reversal effect. A new mathematical analysis of this method is performed in 22 applications.Two formulations of the AHP show to be equivalent in solution and behavior in the sensitivityanalysis. The sensitivity analysis carried out includes a standard part using the critical element, andtwo new analyzes using the critical column vector and condition number. In some cases, AHP is moresensitive to perturbations in the critical column vector than to perturbations in the critical element. Thecritical column vector is unique independently of whether the perturbation is relative orabsolute. Thesensitivity analysis using the condition number reveals that the rank reversal will always exist for everylinear method. Algebraic transformations for deficient rank matrix are performed to obtain a more stableand reliable method., O Analytic Hierarchy Process (AHP) é um método de apoio à decisão tendo como uma das maiores críticas o efeito de reversão de ranking. Uma nova análise matemática deste método é realizada em 22 aplicações. Duas formulações do AHP mostram-se equivalentes em solução e comportamento na análise de sensibilidade. A análise de sensibilidade realizada inclui uma parte típica usando o elemento crítico e duas novas análises usando o vetor coluna crítica e o número de condicionamento. Em alguns casos, o AHP é mais sensível a perturbações no vetor coluna crítico do que a perturbações no elemento crítico. O vetor coluna crítico é único, independentemente da perturbação ser relativa ou absoluta. A análise de sensibilidade usando o número de condicionamento revela que a reversão de ranking sempre existirá para todo método linear. Transformações algébricas para matrizes com posto incompleto são realizadas para obter um método mais estável e confiável.Palavras chave: Análise múltiple critérios, análise de decisão, reversão de ranking, sistemas lineares de equações, análise de sensibilidade, tomada de decisão.

The Analytic Hierarchy Process (AHP) is a decision making method, which has as its greatestcriticism the rank reversal effect. A new mathematical analysis of this method is performed in 22 applications.Two formulations of the AHP show to be equivalent in solution and behavior in the sensitivityanalysis. The sensitivity analysis carried out includes a standard part using the critical element, andtwo new analyzes using the critical column vector and condition number. In some cases, AHP is moresensitive to perturbations in the critical column vector than to perturbations in the critical element. Thecritical column vector is unique independently of whether the perturbation is relative orabsolute. Thesensitivity analysis using the condition number reveals that the rank reversal will always exist for everylinear method. Algebraic transformations for deficient rank matrix are performed to obtain a more stableand reliable method., O Analytic Hierarchy Process (AHP) é um método de apoio à decisão tendo como uma das maiores críticas o efeito de reversão de ranking. Uma nova análise matemática deste método é realizada em 22 aplicações. Duas formulações do AHP mostram-se equivalentes em solução e comportamento na análise de sensibilidade. A análise de sensibilidade realizada inclui uma parte típica usando o elemento crítico e duas novas análises usando o vetor coluna crítica e o número de condicionamento. Em alguns casos, o AHP é mais sensível a perturbações no vetor coluna crítico do que a perturbações no elemento crítico. O vetor coluna crítico é único, independentemente da perturbação ser relativa ou absoluta. A análise de sensibilidade usando o número de condicionamento revela que a reversão de ranking sempre existirá para todo método linear. Transformações algébricas para matrizes com posto incompleto são realizadas para obter um método mais estável e confiável.Palavras chave: Análise múltiple critérios, análise de decisão, reversão de ranking, sistemas lineares de equações, análise de sensibilidade, tomada de decisão.

A simple model for QCD dynamics in which the DGLAP integro-differential equation may be solved analytically has been considered in our previous papers arXiv:1611.08787 [hep-ph] and arXiv:1906.07924 [hep-ph]. When such a model contains only one term in the splitting function of the dominant parton distribution, then Bessel function appears to be the solution to this simplified DGLAP equation. To our knowledge, this model with only one term in the splitting function for the first time has been proposed by Blumlein in hep-ph/9506403. In arXiv:1906.07924 [hep-ph] we have shown that a dual integro-differential equation obtained from the DGLAP equation by a complex map in the plane of the Mellin moment in this model may be considered as the BFKL equation. Then, in arXiv:1906.07924 we have applied a complex diffeomorphism to obtain a standard integral from Gradshteyn and Ryzhik tables starting from the contour integral for parton distribution functions that is usually taken by calculus of residues. This standard integral from these tables appears to be the Laplace transformation of Jacobian for this complex diffeomorphism. Here we write up all the formulae behind this trick in detail and find out certain important points for further development of this strategy. We verify that the inverse Laplace transformation of the Laplace image of the Bessel function may be represented in a form of Barnes contour integral., Comment: 14 pages

A simple model for QCD dynamics in which the DGLAP integro-differential equation may be solved analytically has been considered in our previous papers arXiv:1611.08787 [hep-ph] and arXiv:1906.07924 [hep-ph]. When such a model contains only one term in the splitting function of the dominant parton distribution, then Bessel function appears to be the solution to this simplified DGLAP equation. To our knowledge, this model with only one term in the splitting function for the first time has been proposed by Blumlein in hep-ph/9506403. In arXiv:1906.07924 [hep-ph] we have shown that a dual integro-differential equation obtained from the DGLAP equation by a complex map in the plane of the Mellin moment in this model may be considered as the BFKL equation. Then, in arXiv:1906.07924 we have applied a complex diffeomorphism to obtain a standard integral from Gradshteyn and Ryzhik tables starting from the contour integral for parton distribution functions that is usually taken by calculus of residues. This standard integral from these tables appears to be the Laplace transformation of Jacobian for this complex diffeomorphism. Here we write up all the formulae behind this trick in detail and find out certain important points for further development of this strategy. We verify that the inverse Laplace transformation of the Laplace image of the Bessel function may be represented in a form of Barnes contour integral., Comment: 14 pages

Gliomas são tumores cerebrais primários agressivos e invasivos, no qual o mais comum e maligno, glioblastoma multiforme, possui uma combinação de rápido crescimento e invasibilidade. Com o avanço na capacidade de processamento e armazenamento de dados, a utilização de métodos estocásticos para a simulação de problemas físicos reais vem se tornando cada vez mais frequentes. O objetivo do trabalho é simular computacionalmente o crescimento do glioma resolvendo uma equação de reação-difusão em 1D, pelo método de Crank-Nicolson e transpor essa solução para uma geometria 3D por meio do método do Cone Causal e de Monte Carlo. Os resultados obtidos fornecem informações da evolução do raio, concentração de células cancerosas, volume e uma visualização em 3D do tumor. Estes resultados encontrados se mostraram satisfatórios quando comparado com trabalhos que estudam o crescimento tumoral.Palavras chave: Equação de Reação-Difusão, Gliomas, Método do Cone Causal, Método de Monte Carlo, Método de Diferenças Finitas.

Gliomas são tumores cerebrais primários agressivos e invasivos, no qual o mais comum e maligno, glioblastoma multiforme, possui uma combinação de rápido crescimento e invasibilidade. Com o avanço na capacidade de processamento e armazenamento de dados, a utilização de métodos estocásticos para a simulação de problemas físicos reais vem se tornando cada vez mais frequentes. O objetivo do trabalho é simular computacionalmente o crescimento do glioma resolvendo uma equação de reação-difusão em 1D, pelo método de Crank-Nicolson e transpor essa solução para uma geometria 3D por meio do método do Cone Causal e de Monte Carlo. Os resultados obtidos fornecem informações da evolução do raio, concentração de células cancerosas, volume e uma visualização em 3D do tumor. Estes resultados encontrados se mostraram satisfatórios quando comparado com trabalhos que estudam o crescimento tumoral.Palavras chave: Equação de Reação-Difusão, Gliomas, Método do Cone Causal, Método de Monte Carlo, Método de Diferenças Finitas.

New hybrid waterborne polyurethane/acrylate (WPUA) dispersions were synthesized by grafting with bisphenol-A-glycidyl dimethacrylate (Bis-GMA) in order to create chemical bonds between polyurethane and polyacrylate chains. WPUAs were prepared by using prepolymer self-emulsifying method with isophorone diisocianate, poly(tetramethylene ether) glycol, dimethylolpropionic acid, and ethylenediamine in the polyurethanic part, and styrene and n-butyl acrylate in the polyacrylate portion. A redox pair system consisting of ascorbic acid and hydrogen peroxide were used as polymerization initiator. The particle size of the WPUA dispersions increased by increasing the Bis-GMA/1,4 butanediol ratio, stable dispersions of negatively charged particles were obtained, and they had low viscosity (around 1.3 mPa.s) in spite of the relatively high solids content (27 wt%). Higher thermal stability was obtained when 50 mol% of chain extension was carried out with Bis-GMA. Using Bis-GMA/BD, instead of HEMA, as grafting agent, allowed obtaining hybrid polyurethane dispersions with the lowest mean particle size and better colloidal stability. Finally, the addition of 35 wt% Bis-GMA increased noticeably the cross-cut adhesion of polyurethane/acrylate coatings to stainless steel.

New hybrid waterborne polyurethane/acrylate (WPUA) dispersions were synthesized by grafting with bisphenol-A-glycidyl dimethacrylate (Bis-GMA) in order to create chemical bonds between polyurethane and polyacrylate chains. WPUAs were prepared by using prepolymer self-emulsifying method with isophorone diisocianate, poly(tetramethylene ether) glycol, dimethylolpropionic acid, and ethylenediamine in the polyurethanic part, and styrene and n-butyl acrylate in the polyacrylate portion. A redox pair system consisting of ascorbic acid and hydrogen peroxide were used as polymerization initiator. The particle size of the WPUA dispersions increased by increasing the Bis-GMA/1,4 butanediol ratio, stable dispersions of negatively charged particles were obtained, and they had low viscosity (around 1.3 mPa.s) in spite of the relatively high solids content (27 wt%). Higher thermal stability was obtained when 50 mol% of chain extension was carried out with Bis-GMA. Using Bis-GMA/BD, instead of HEMA, as grafting agent, allowed obtaining hybrid polyurethane dispersions with the lowest mean particle size and better colloidal stability. Finally, the addition of 35 wt% Bis-GMA increased noticeably the cross-cut adhesion of polyurethane/acrylate coatings to stainless steel.

Microbiome studies show altered microbiota in head and neck squamous cell carcinoma (HNSCC), both in terms of taxonomic composition and metabolic capacity. These studies utilized a traditional bioinformatics methodology, which allows for accurate taxonomic assignment down to the genus level, but cannot accurately resolve species level membership. We applied Resphera Insight, a high-resolution methodology for 16S rRNA taxonomic assignment that is able to provide species-level context in its assignments of 16S rRNA next generation sequencing (NGS) data. Resphera Insight applied to saliva samples from HNSCC patients and healthy controls led to the discovery that a subset of HNSCC saliva samples is significantly enriched with commensal species from the vaginal flora, including Lactobacillus gasseri/johnsonii (710x higher in saliva) and Lactobacillus vaginalis (52x higher in saliva). These species were not observed in normal saliva from Johns Hopkins patients, nor in 16S rRNA NGS saliva samples from the Human Microbiome Project (HMP). Interestingly, both species were only observed in saliva from Human Papilloma Virus (HPV) positive and HPV negative oropharyngeal cancer patients. We confirmed the representation of both species in HMP data obtained from mid-vagina (n=128) and vaginal introitus (n=121) samples. Resphera Insight also led to the discovery that Fusobacterium nucleatum, an oral cavity flora commensal bacterium linked to colon cancer, is enriched (600x higher) in saliva from a subset of HNSCC patients with advanced tumors stages. Together, these high-resolution analyses on 583 samples suggest a possible role for bacterial species in the therapeutic outcome of HPV positive and HPV negative HNSCC patients.

Microbiome studies show altered microbiota in head and neck squamous cell carcinoma (HNSCC), both in terms of taxonomic composition and metabolic capacity. These studies utilized a traditional bioinformatics methodology, which allows for accurate taxonomic assignment down to the genus level, but cannot accurately resolve species level membership. We applied Resphera Insight, a high-resolution methodology for 16S rRNA taxonomic assignment that is able to provide species-level context in its assignments of 16S rRNA next generation sequencing (NGS) data. Resphera Insight applied to saliva samples from HNSCC patients and healthy controls led to the discovery that a subset of HNSCC saliva samples is significantly enriched with commensal species from the vaginal flora, including Lactobacillus gasseri/johnsonii (710x higher in saliva) and Lactobacillus vaginalis (52x higher in saliva). These species were not observed in normal saliva from Johns Hopkins patients, nor in 16S rRNA NGS saliva samples from the Human Microbiome Project (HMP). Interestingly, both species were only observed in saliva from Human Papilloma Virus (HPV) positive and HPV negative oropharyngeal cancer patients. We confirmed the representation of both species in HMP data obtained from mid-vagina (n=128) and vaginal introitus (n=121) samples. Resphera Insight also led to the discovery that Fusobacterium nucleatum, an oral cavity flora commensal bacterium linked to colon cancer, is enriched (600x higher) in saliva from a subset of HNSCC patients with advanced tumors stages. Together, these high-resolution analyses on 583 samples suggest a possible role for bacterial species in the therapeutic outcome of HPV positive and HPV negative HNSCC patients.

We consider a simple model for QCD dynamics in which DGLAP integro-differential equation may be solved analytically. This is a gauge model which possesses dominant evolution of gauge boson (gluon) distribution and in which the gauge coupling does not run. This may be ${\cal N} =4$ supersymmetric gauge theory with softly broken supersymmetry, other finite supersymmetric gauge theory with lower level of supersymmetry, or topological Chern-Simons field theories. We maintain only one term in the splitting function of unintegrated gluon distribution and solve DGLAP analytically for this simplified splitting function. The solution is found by use of the Cauchy integral formula. The solution restricts form of the unintegrated gluon distribution as function of momentum transfer and of Bjorken $x$. Then we consider an almost realistic splitting function of unintegrated gluon distribution as an input to DGLAP equation and solve it by the same method which we have developed to solve DGLAP equation for the toy-model. We study a result obtained for the realistic gluon distribution and find a singular Bessel-like behaviour in the vicinity of the point $x=0$ and a smooth behaviour in the vicinity of the point, Comment: 32 pages

"42 different approaches to transmit the generative source of creativity in live action by internationally experienced practitioners, teachers and theorists of performance art from 21 countries." -- Publisher's website.

The classical orbits of an electron with anisotropic mass interacting with a Coulomb center in the presence of a magnetic field are investigated. It is shown that the shape and duration of the closed orbits depend on the magnetic-field direction. Reasonable agreement with available experimental results for donor-doped silicon samples in a magnetic field is found, when the energy value of the conduction electron is appropriately chosen.

The purpose of the present study was to compare the profiles of physical self-concept between men and women high school Mexican students. A total sample of 709 participants, 324 women and 385 men, aged 13-19 years participated in this study. A quantitative approach with a descriptive and transversal survey design was used. All the participants completed the Physical Self-Description Questionnaire. Results of the one-way multivariate analysis of variance, followed by the one-way univariate analysis of variance, showed that in comparison among women, men obtained higher scores on the health, coordination, activity, sports competence, strength, flexibility, endurance, global physical self-concept and global self-esteem subscales. However, in the body fat and appearance subscales statistically significant differences were not found because of the differences between men and women in their perception of their physical self-concept, these findings suggest that in order to design any intervention for improving the perceived physical self-concept of the students, the variable gender should be taken into account

Por medio de esta investigación se pretende identificar las posibilidades de mejorar la eficiencia de las empresas prestadoras de los servicios de acueducto y alcantarillado (ESP) en Antioquia -- Para tal fin es importante analizar la historia del funcionamiento y las características del sector de acueducto y alcantarillado en Antioquia en los últimos años, concretamente, comprender qué factores hacen que determinadas empresas sean más eficientes que otras y qué factores ayudaron a determinar el escenario actual de la prestación de dicho servicio es este departamento -- Además, se debe entender que factores que determinan los costos administrativos y operativos afectan la eficiencia en la prestación del servicio de acueducto y alcantarillado -- Para esto se utilizará la Metodología DEA con el fin de comparar la eficiencia de las empresas prestadoras del servicio de acueducto y alcantarillado en Antioquia, agrupando las empresas por tipo (pública, privada o mixta) y así concluir si esta característica afecta su puntaje de eficiencia comparativa -- Por medio de la metodología utilizada para medir la eficiencia comparativa se pudo concluir que más allá de que una empresa sea pública o privada, hay factores que tienen mayor peso para determinar la eficiencia -- Dichos factores incluyen el número de usuarios, la complejidad del sistema respecto al tamaño de las redes, la distancia entre un usuario y otro, la forma como la empresa maneja la operación y el tipo de usuarios que tienen las empresas que se encuentran en Colombia clasificados según estrato

"42 different approaches to transmit the generative source of creativity in live action by internationally experienced practitioners, teachers and theorists of performance art from 21 countries." -- Publisher's website.

The purpose of the present study was to compare the profiles of physical self-concept between men and women high school Mexican students. A total sample of 709 participants, 324 women and 385 men, aged 13-19 years participated in this study. A quantitative approach with a descriptive and transversal survey design was used. All the participants completed the Physical Self-Description Questionnaire. Results of the one-way multivariate analysis of variance, followed by the one-way univariate analysis of variance, showed that in comparison among women, men obtained higher scores on the health, coordination, activity, sports competence, strength, flexibility, endurance, global physical self-concept and global self-esteem subscales. However, in the body fat and appearance subscales statistically significant differences were not found because of the differences between men and women in their perception of their physical self-concept, these findings suggest that in order to design any intervention for improving the perceived physical self-concept of the students, the variable gender should be taken into account

The purpose of the present study was to compare the profiles of physical self-concept between men and women high school Mexican students. A total sample of 709 participants, 324 women and 385 men, aged 13-19 years participated in this study. A quantitative approach with a descriptive and transversal survey design was used. All the participants completed the Physical Self-Description Questionnaire. Results of the one-way multivariate analysis of variance, followed by the one-way univariate analysis of variance, showed that in comparison among women, men obtained higher scores on the health, coordination, activity, sports competence, strength, flexibility, endurance, global physical self-concept and global self-esteem subscales. However, in the body fat and appearance subscales statistically significant differences were not found because of the differences between men and women in their perception of their physical self-concept, these findings suggest that in order to design any intervention for improving the perceived physical self-concept of the students, the variable gender should be taken into account

Drug trafficking has been a menace in most Latin American countries for many decades. We know enough about how the phenomenon works as an economic and social problem and how it affects the continent, but in the last decade, with the attention of the world on Islamic extremist terrorism, there has been a diversion of resources and political attention from how drug trafficking has evolved and how much of a threat it is currently posing to the developing democracies in Latin America. This thesis explores just how critical the problem of drug trafficking currently is in Central America and what consequences we can expect for the region and for the US. This study is important because it sheds light on a problem that has not only dramatically grown and spread throughout many Latin American countries but has acquired new objectives and operational concepts that have probably turned it into the most lethal regional threat against many of the fragile developing democracies particularly in Central America. This work also explores the growing threat that this situation poses directly to the US. My primary question is: How has drug trafficking evolved in Latin America and what level of threat does it pose to Central America? The methodology I used to serve my thesis was a deductive one. I looked into the effect patterns of drug trafficking in the Andean region of South America and compared them to those of Mexico, which is the most recent focal point of drug trafficking in Latin America, in order to prove their evolving changes and effects on the health of the states they operate in. The results can be extrapolated into the political, economic and social environment of Central America in order to project the consequences of drug trafficking in the next 10 years., The original document contains color images.

Elastomer films with three-dimensional features self-organized into coherent and semi-coherent buckling domains were created by implanting different species of metal ions and combinations thereof, using a metal evaporation ion source, into quality polydimethylsiloxane films. As a result of the implantation process, functionalized discrete regions of strain-induced surface buckling were created, taking the forms of domains of parallel surface waves, semi-ordered regions and disordered regions. In addition, deep, strain-induced, V-shaped cracks were observed to penetrate well into the elastomer matrix. Characterization was via optical microscopy, X-ray diffraction, atomic force microscopy and high-resolution scanning electron microscopy (SEM) in the form of field emission SEM. It was found that controlling the localized strain by altering the metal ion species can control the frequency of the V-shaped cracks and the properties of the buckled areas. These observations and possible mechanisms for the formation of the cracks and domains are discussed in this paper.

Elastomer films with three-dimensional features self-organized into coherent and semi-coherent buckling domains were created by implanting different species of metal ions and combinations thereof, using a metal evaporation ion source, into quality polydimethylsiloxane films. As a result of the implantation process, functionalized discrete regions of strain-induced surface buckling were created, taking the forms of domains of parallel surface waves, semi-ordered regions and disordered regions. In addition, deep, strain-induced, V-shaped cracks were observed to penetrate well into the elastomer matrix. Characterization was via optical microscopy, X-ray diffraction, atomic force microscopy and high-resolution scanning electron microscopy (SEM) in the form of field emission SEM. It was found that controlling the localized strain by altering the metal ion species can control the frequency of the V-shaped cracks and the properties of the buckled areas. These observations and possible mechanisms for the formation of the cracks and domains are discussed in this paper.

Elastomer films with three-dimensional features self-organized into coherent and semi-coherent buckling domains were created by implanting different species of metal ions and combinations thereof, using a metal evaporation ion source, into quality polydimethylsiloxane films. As a result of the implantation process, functionalized discrete regions of strain-induced surface buckling were created, taking the forms of domains of parallel surface waves, semi-ordered regions and disordered regions. In addition, deep, strain-induced, V-shaped cracks were observed to penetrate well into the elastomer matrix. Characterization was via optical microscopy, X-ray diffraction, atomic force microscopy and high-resolution scanning electron microscopy (SEM) in the form of field emission SEM. It was found that controlling the localized strain by altering the metal ion species can control the frequency of the V-shaped cracks and the properties of the buckled areas. These observations and possible mechanisms for the formation of the cracks and domains are discussed in this paper.

Elastomer films with three-dimensional features self-organized into coherent and semi-coherent buckling domains were created by implanting different species of metal ions and combinations thereof, using a metal evaporation ion source, into quality polydimethylsiloxane films. As a result of the implantation process, functionalized discrete regions of strain-induced surface buckling were created, taking the forms of domains of parallel surface waves, semi-ordered regions and disordered regions. In addition, deep, strain-induced, V-shaped cracks were observed to penetrate well into the elastomer matrix. Characterization was via optical microscopy, X-ray diffraction, atomic force microscopy and high-resolution scanning electron microscopy (SEM) in the form of field emission SEM. It was found that controlling the localized strain by altering the metal ion species can control the frequency of the V-shaped cracks and the properties of the buckled areas. These observations and possible mechanisms for the formation of the cracks and domains are discussed in this paper.

We report synthesis, structure, electrical transport, and heat capacity of SmFeAsO. The title compound is synthesized by one-step encapsulation of stoichiometric FeAs, Sm, and Sm2O3 in an evacuated (10−5 Torr) quartz tube by prolong (72 h) annealing at 1100 °C. The as-synthesized compound is crystallized in tetragonal structure with P4/nmm space group having lattice parameters a = 3.937 26(33) A and c = 8.498 02(07) A. The resistance (R-T) measurements on the compound exhibited ground state spin-density-wave (SDW)-like metallic steps below 140 K. Heat capacity CP(T) measurements on the title compound, showed an anomaly at around 140 K, which is reminiscent of the SDW ordering of the compound. At lower temperatures the CP(T) shows a clear peak at around 4.5 K. At lower temperature below 20 K, Cp(T) is also measured under an applied field of 7 T. It is concluded that the CP(T) peak at 4.5 K is due to the antiferromagnetic ordering of Sm3+ spins. These results are in confirmation with ordering of Sm in Sm2−xCexCuO4.

We report synthesis, structure, electrical transport, and heat capacity of SmFeAsO. The title compound is synthesized by one-step encapsulation of stoichiometric FeAs, Sm, and Sm2O3 in an evacuated (10−5 Torr) quartz tube by prolong (72 h) annealing at 1100 °C. The as-synthesized compound is crystallized in tetragonal structure with P4/nmm space group having lattice parameters a = 3.937 26(33) A and c = 8.498 02(07) A. The resistance (R-T) measurements on the compound exhibited ground state spin-density-wave (SDW)-like metallic steps below 140 K. Heat capacity CP(T) measurements on the title compound, showed an anomaly at around 140 K, which is reminiscent of the SDW ordering of the compound. At lower temperatures the CP(T) shows a clear peak at around 4.5 K. At lower temperature below 20 K, Cp(T) is also measured under an applied field of 7 T. It is concluded that the CP(T) peak at 4.5 K is due to the antiferromagnetic ordering of Sm3+ spins. These results are in confirmation with ordering of Sm in Sm2−xCexCuO4.

We report synthesis, structure, electrical transport, and heat capacity of SmFeAsO. The title compound is synthesized by one-step encapsulation of stoichiometric FeAs, Sm, and Sm2O3 in an evacuated (10−5 Torr) quartz tube by prolong (72 h) annealing at 1100 °C. The as-synthesized compound is crystallized in tetragonal structure with P4/nmm space group having lattice parameters a = 3.937 26(33) A and c = 8.498 02(07) A. The resistance (R-T) measurements on the compound exhibited ground state spin-density-wave (SDW)-like metallic steps below 140 K. Heat capacity CP(T) measurements on the title compound, showed an anomaly at around 140 K, which is reminiscent of the SDW ordering of the compound. At lower temperatures the CP(T) shows a clear peak at around 4.5 K. At lower temperature below 20 K, Cp(T) is also measured under an applied field of 7 T. It is concluded that the CP(T) peak at 4.5 K is due to the antiferromagnetic ordering of Sm3+ spins. These results are in confirmation with ordering of Sm in Sm2−xCexCuO4.

Perovskite solid solution ceramics with compositions of 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3, 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3, and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 were synthesized by the traditional solid state reaction method. Ferroelectric measurements revealed that these samples have well saturated polarization-electrical field loops. Dielectric measurements showed that abnormal dielectric peaks at their Curie temperature were frequency dependent. Both characteristics indicate that these samples are relaxor type ferroelectric materials. Field cooled and zero field cooled magnetization measurements revealed that the 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3 and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 samples are paramagnetic down to 5 K, while the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample shows an antiferromagnetic-like ordering starting from around 40 K. Furthermore, a weak ferromagnetism is observed in the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample, as evidenced by the magnetic hysteresis loop measured at 10 K. The ac susceptibility measurement of this sample showed that the peak position around 40 K is strongly dependent on frequency, indicating a glassy or relaxor type bahavior below that temperature. Therefore, relaxor type ferroelectric and magnetic 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 is a magnetoelectric relaxor.

Perovskite solid solution ceramics with compositions of 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3, 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3, and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 were synthesized by the traditional solid state reaction method. Ferroelectric measurements revealed that these samples have well saturated polarization-electrical field loops. Dielectric measurements showed that abnormal dielectric peaks at their Curie temperature were frequency dependent. Both characteristics indicate that these samples are relaxor type ferroelectric materials. Field cooled and zero field cooled magnetization measurements revealed that the 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3 and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 samples are paramagnetic down to 5 K, while the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample shows an antiferromagnetic-like ordering starting from around 40 K. Furthermore, a weak ferromagnetism is observed in the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample, as evidenced by the magnetic hysteresis loop measured at 10 K. The ac susceptibility measurement of this sample showed that the peak position around 40 K is strongly dependent on frequency, indicating a glassy or relaxor type bahavior below that temperature. Therefore, relaxor type ferroelectric and magnetic 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 is a magnetoelectric relaxor.

Perovskite solid solution ceramics with compositions of 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3, 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3, and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 were synthesized by the traditional solid state reaction method. Ferroelectric measurements revealed that these samples have well saturated polarization-electrical field loops. Dielectric measurements showed that abnormal dielectric peaks at their Curie temperature were frequency dependent. Both characteristics indicate that these samples are relaxor type ferroelectric materials. Field cooled and zero field cooled magnetization measurements revealed that the 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3 and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 samples are paramagnetic down to 5 K, while the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample shows an antiferromagnetic-like ordering starting from around 40 K. Furthermore, a weak ferromagnetism is observed in the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample, as evidenced by the magnetic hysteresis loop measured at 10 K. The ac susceptibility measurement of this sample showed that the peak position around 40 K is strongly dependent on frequency, indicating a glassy or relaxor type bahavior below that temperature. Therefore, relaxor type ferroelectric and magnetic 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 is a magnetoelectric relaxor.

In this work we report on interlayer spin-polarized transport studies carried out on YBa2Cu3O7-δ/La2/3Sr1/3MnO3/YBa2Cu3O7-δ thin film multilayers. Anisotropic YBa2Cu3O7-δ high-temperature superconductors (YBCO) and the manganite La2/3Sr1/3MnO3 (LSMO) are layered metallic systems where the c-axis interlayer current transport occurs via sequential tunneling of charge carriers. The temperature dependence of the resistance R(T) for different applied fields shows that these heterostructures are clearly influenced by both the insulator-to-metal transition of the LSMO layers at ∼ 320 K and the stripe fluctuations in the conductivity of the YBCO layers at the onset of electronic inhomogeneity at ∼ 210 K. Furthermore, the tunneling of spin-polarized charge carriers between the YBCO layers through LSMO showed sharp switching between the high and low resistance states, which we assume corresponds to antiparallel and parallel alignments of the magnetic (spin) moments of these hybrid structures. The investigation of these promising hybrid structures is aimed at understanding the science of the new spin-based devices, laying the foundation for a new generation of ultrafast, nonvolatile electronics.

In this work we report on interlayer spin-polarized transport studies carried out on YBa2Cu3O7-δ/La2/3Sr1/3MnO3/YBa2Cu3O7-δ thin film multilayers. Anisotropic YBa2Cu3O7-δ high-temperature superconductors (YBCO) and the manganite La2/3Sr1/3MnO3 (LSMO) are layered metallic systems where the c-axis interlayer current transport occurs via sequential tunneling of charge carriers. The temperature dependence of the resistance R(T) for different applied fields shows that these heterostructures are clearly influenced by both the insulator-to-metal transition of the LSMO layers at ∼ 320 K and the stripe fluctuations in the conductivity of the YBCO layers at the onset of electronic inhomogeneity at ∼ 210 K. Furthermore, the tunneling of spin-polarized charge carriers between the YBCO layers through LSMO showed sharp switching between the high and low resistance states, which we assume corresponds to antiparallel and parallel alignments of the magnetic (spin) moments of these hybrid structures. The investigation of these promising hybrid structures is aimed at understanding the science of the new spin-based devices, laying the foundation for a new generation of ultrafast, nonvolatile electronics.

Perovskite solid solution ceramics with compositions of 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3, 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3, and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 were synthesized by the traditional solid state reaction method. Ferroelectric measurements revealed that these samples have well saturated polarization-electrical field loops. Dielectric measurements showed that abnormal dielectric peaks at their Curie temperature were frequency dependent. Both characteristics indicate that these samples are relaxor type ferroelectric materials. Field cooled and zero field cooled magnetization measurements revealed that the 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3 and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 samples are paramagnetic down to 5 K, while the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample shows an antiferromagnetic-like ordering starting from around 40 K. Furthermore, a weak ferromagnetism is observed in the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample, as evidenced by the magnetic hysteresis loop measured at 10 K. The ac susceptibility measurement of this sample showed that the peak position around 40 K is strongly dependent on frequency, indicating a glassy or relaxor type bahavior below that temperature. Therefore, relaxor type ferroelectric and magnetic 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 is a magnetoelectric relaxor.

We report synthesis, structure, electrical transport, and heat capacity of SmFeAsO. The title compound is synthesized by one-step encapsulation of stoichiometric FeAs, Sm, and Sm2O3 in an evacuated (10−5 Torr) quartz tube by prolong (72 h) annealing at 1100 °C. The as-synthesized compound is crystallized in tetragonal structure with P4/nmm space group having lattice parameters a = 3.937 26(33) A and c = 8.498 02(07) A. The resistance (R-T) measurements on the compound exhibited ground state spin-density-wave (SDW)-like metallic steps below 140 K. Heat capacity CP(T) measurements on the title compound, showed an anomaly at around 140 K, which is reminiscent of the SDW ordering of the compound. At lower temperatures the CP(T) shows a clear peak at around 4.5 K. At lower temperature below 20 K, Cp(T) is also measured under an applied field of 7 T. It is concluded that the CP(T) peak at 4.5 K is due to the antiferromagnetic ordering of Sm3+ spins. These results are in confirmation with ordering of Sm in Sm2−xCexCuO4.

We report the magnetic and magnetotransport properties of Ca doped La1-xCaxCrO3 (x=0, 0.1, 0.2, and 0.3). Both the magnetic and transport properties are very sensitive to Ca substitution. The Neel temperature T-N decreases substantially with increasing calcium doping concentration from 290 to 160 K. A weak ferromagnetic state with large coercive fields of up to 3 T is present for the Ca doped LaCrO3. The temperature dependence of the resistivity shows that all the Ca doped com#163s are semiconducting and their resistivities decrease with increasing Ca for low doping levels. The resistivity curves show thermally activated behavior and a variable range hopping behavior at high temperatures. The magnetotransport measurements show a negative magnetoresistance. Furthermore, an anomalous peak was observed in the field dependence of magnetoresistance for the LCCO materials.

We report the magnetic and magnetotransport properties of Ca doped La1-xCaxCrO3 (x=0, 0.1, 0.2, and 0.3). Both the magnetic and transport properties are very sensitive to Ca substitution. The Neel temperature T-N decreases substantially with increasing calcium doping concentration from 290 to 160 K. A weak ferromagnetic state with large coercive fields of up to 3 T is present for the Ca doped LaCrO3. The temperature dependence of the resistivity shows that all the Ca doped com#163s are semiconducting and their resistivities decrease with increasing Ca for low doping levels. The resistivity curves show thermally activated behavior and a variable range hopping behavior at high temperatures. The magnetotransport measurements show a negative magnetoresistance. Furthermore, an anomalous peak was observed in the field dependence of magnetoresistance for the LCCO materials.

We report the magnetic and magnetotransport properties of Ca doped La1-xCaxCrO3 (x=0, 0.1, 0.2, and 0.3). Both the magnetic and transport properties are very sensitive to Ca substitution. The Neel temperature T-N decreases substantially with increasing calcium doping concentration from 290 to 160 K. A weak ferromagnetic state with large coercive fields of up to 3 T is present for the Ca doped LaCrO3. The temperature dependence of the resistivity shows that all the Ca doped com#163s are semiconducting and their resistivities decrease with increasing Ca for low doping levels. The resistivity curves show thermally activated behavior and a variable range hopping behavior at high temperatures. The magnetotransport measurements show a negative magnetoresistance. Furthermore, an anomalous peak was observed in the field dependence of magnetoresistance for the LCCO materials.

We investigated the emission of subterahertz frequency electromagnetic radiation from high-TC superconducting c-axis NdBa2Cu3O7−8/PrBa2Cu3O7−8/NdBa2Cu3O7−8 trilayer thin film tunneling junctions when external electric and magnetic fields are applied. The current-voltage characteristics under applied ab-plane magnetic fields H (up 8 T) exhibit well defined steps, Vn, such that eVn -hwp / (2n), where the plasma frequency wp-0.4 THz and n=1,2,3, . . . .. These steps may be interpreted using Josephson plasma dynamics. The applied voltage creates oscillating currents via the Josephson coupling energy EJ (EJ=hIJ /4e, where IJ is the Josephson current and h is Planck’s constant) and the charge energy EC (EC=e2 /2C, where C is the junction capacitance). Thus the Josephson plasma becomes excited by the tunneling current, with some of the energy being emitted as subterahertz frequency radiation. Our results provide a new insight into a solid-state quantum system with considerable potential for new solid-state terahertz emission sources.

We investigated the emission of subterahertz frequency electromagnetic radiation from high-TC superconducting c-axis NdBa2Cu3O7−8/PrBa2Cu3O7−8/NdBa2Cu3O7−8 trilayer thin film tunneling junctions when external electric and magnetic fields are applied. The current-voltage characteristics under applied ab-plane magnetic fields H (up 8 T) exhibit well defined steps, Vn, such that eVn -hwp / (2n), where the plasma frequency wp-0.4 THz and n=1,2,3, . . . .. These steps may be interpreted using Josephson plasma dynamics. The applied voltage creates oscillating currents via the Josephson coupling energy EJ (EJ=hIJ /4e, where IJ is the Josephson current and h is Planck’s constant) and the charge energy EC (EC=e2 /2C, where C is the junction capacitance). Thus the Josephson plasma becomes excited by the tunneling current, with some of the energy being emitted as subterahertz frequency radiation. Our results provide a new insight into a solid-state quantum system with considerable potential for new solid-state terahertz emission sources.

We report the magnetic and magnetotransport properties of Ca doped La1-xCaxCrO3 (x=0, 0.1, 0.2, and 0.3). Both the magnetic and transport properties are very sensitive to Ca substitution. The Neel temperature T-N decreases substantially with increasing calcium doping concentration from 290 to 160 K. A weak ferromagnetic state with large coercive fields of up to 3 T is present for the Ca doped LaCrO3. The temperature dependence of the resistivity shows that all the Ca doped com#163s are semiconducting and their resistivities decrease with increasing Ca for low doping levels. The resistivity curves show thermally activated behavior and a variable range hopping behavior at high temperatures. The magnetotransport measurements show a negative magnetoresistance. Furthermore, an anomalous peak was observed in the field dependence of magnetoresistance for the LCCO materials.

We investigated the emission of subterahertz frequency electromagnetic radiation from high-TC superconducting c-axis NdBa2Cu3O7−8/PrBa2Cu3O7−8/NdBa2Cu3O7−8 trilayer thin film tunneling junctions when external electric and magnetic fields are applied. The current-voltage characteristics under applied ab-plane magnetic fields H (up 8 T) exhibit well defined steps, Vn, such that eVn -hwp / (2n), where the plasma frequency wp-0.4 THz and n=1,2,3, . . . .. These steps may be interpreted using Josephson plasma dynamics. The applied voltage creates oscillating currents via the Josephson coupling energy EJ (EJ=hIJ /4e, where IJ is the Josephson current and h is Planck’s constant) and the charge energy EC (EC=e2 /2C, where C is the junction capacitance). Thus the Josephson plasma becomes excited by the tunneling current, with some of the energy being emitted as subterahertz frequency radiation. Our results provide a new insight into a solid-state quantum system with considerable potential for new solid-state terahertz emission sources.

Anisotropic RBa2Cu3O7-σ high temperature superconductors (RBCO), where R represents the rare earth elements Y, Nd and Pr, as well as the layered manganite La2/3Sr1/3MnO3 (LSMO), are layered metallic systems where the interlayer current transport occurs via sequential tunneling of charge carriers. We present here experimental results of interlayer spin polarized transport studies carried out on YBa2Cu3O7-σ/La2/3Sr1/3MnO3/YBa2Cu3O7-σ thin film multilayers. The tunneling of spin polarized charge carriers between the YBCO layers through LSMO leads to a novel spin valve effects at high temperatures. Our samples showed large magneto-resistance with a sharp switching between the high and low resistance states, which we assume corresponds to antiparallel and parallel alignment of the moments of these hybrid structures. The investigation of these promising hybrid structures is aimed at understanding the science of the new spin-based devices, laying the foundation for a new generation of ultra-fast, non-volatile electronics.

YBa2Cu3O7-δ high temperature superconductors (YBCO), as well as the layered manganite La2/3Sr1/3MnO3 (LSMO) are layered metallic systems where the interlayer current transport occurs via sequential tunneling of charge carriers. We present in this paper experimental results of magneto-transport studies carried out on YBa2Cu3O7-δ/La2/3Sr1/3MnO3/YBa2Cu3O7-δ (YBCO/LSMO/YBCO) thin film multilayers. The YBCO/LSMO/YBCO heterostructures were grown on SrTiO3 (STO) substrates by pulsed laser deposition. The close lattice match among the constituent layers of the perovskite YBCO/LSMO/YBCO and the substrate facilitates epitaxial film growth, thus minimizing strong spin-flip scattering at the interface. The temperature dependence of the resistance for different bias currents shows that these heterostructures are clearly influenced by both the insulator-to-metal transition of the LSMO layers at 330 K and the stripe fluctuations in the conductivity of the YBCO layers at the onset of electronic inhomogeneity at ~240 K. The samples show a drop between 19% and 22% in the resistance for the c-axis tunneling currents varying from I = 0.05-1.0 mA at the critical temperature T* ~ 240 K. This behavior could be related to the opening of a pseudogap. The investigation of these promising hybrid structures is aimed at understanding the science of new spin-based devices.

High quality YBa2Cu3O7 (YBCO) films and multilayers of ReBa2Cu3O7 superconductors, where Re is rare earth elements (Y and Nd), have been prepared by pulsed laser deposition. Pinning characteristics of the structures obtained have been analysed and attributed to growth conditions and corresponding structural peculiarities. Relatively thick (~1 µm) multilayers exhibit better performance than mono-layer YBCO films having arbitrary thickness. differences in the films and multilayers are discussed in terms of their structure homogeneity and defects induced by the growth of the layers.

High quality YBa2Cu3O7 (YBCO) films and multilayers of ReBa2Cu3O7 superconductors, where Re is rare earth elements (Y and Nd), have been prepared by pulsed laser deposition. Pinning characteristics of the structures obtained have been analysed and attributed to growth conditions and corresponding structural peculiarities. Relatively thick (~1 µm) multilayers exhibit better performance than mono-layer YBCO films having arbitrary thickness. differences in the films and multilayers are discussed in terms of their structure homogeneity and defects induced by the growth of the layers.

High quality YBa2Cu3O7 (YBCO) films and multilayers of ReBa2Cu3O7 superconductors, where Re is rare earth elements (Y and Nd), have been prepared by pulsed laser deposition. Pinning characteristics of the structures obtained have been analysed and attributed to growth conditions and corresponding structural peculiarities. Relatively thick (~1 µm) multilayers exhibit better performance than mono-layer YBCO films having arbitrary thickness. differences in the films and multilayers are discussed in terms of their structure homogeneity and defects induced by the growth of the layers.