Isquemia intestinal, una manifestación inusual de la embolia paradójica. Un reporte de caso / Intestinal ischaemia as a rare manifestation of a paradoxical embolism. A case report

Introducción. La embolia paradójica es un evento trombótico originado en la circulación venosa, que se manifiesta como embolismo arterial por medio de un defecto anatómico a nivel cardíaco o pulmonar. Se asocia principalmente a eventos cerebrovasculares, aunque se han encontrado casos de infarto agudo de miocardio, infarto renal y otros eventos isquémicos. Caso clínico. Paciente de 47 años, quien consultó por cuadro de dolor abdominal, que requirió manejo quirúrgico de urgencia, donde identificaron isquemia intestinal importante. Los estudios adicionales hallaron déficit de proteína S y persistencia de foramen oval permeable. Resultados. La presencia de trombosis arterial se conoce como trombosis de sitios inusuales y requiere de estudios para descartar trombofilias asociadas u otros estados protrombóticos. El déficit de proteína S es una trombofilia infrecuente, la cual se asocia en la vida adulta a eventos trombóticos de origen venoso. En presencia de defectos anatómicos, como un foramen oval permeable, puede progresar a embolia arterial, configurando un cuadro de embolismo paradójico. La estratificación de estos pacientes requiere imágenes que demuestran el defecto mencionado, así como el posible origen de los émbolos. El manejo se basa en anticoagulación plena, manejo de soporte, resolver las manifestaciones trombóticas existentes y un cierre temprano del defecto anatómico. Conclusiones. El embolismo paradójico debe sospecharse en caso de trombosis de sitios inusuales. Requiere de un estudio exhaustivo con imágenes y su manejo debe basarse en anticoagulación y cierre del defecto.

Introduction. Paradoxical embolism is a thrombotic event originating in the venous circulation, which manifests as arterial embolism through an anatomical cardiac or pulmonary defect. It is mainly associated with stroke, also presenting as acute myocardial infarction, renal infarction, and other ischemic events. Clinical case. A 47-year-old patient was admitted due to abdominal pain, which required emergency surgical management, finding significant intestinal ischemia. Additional studies found protein S deficiency and evidence of a patent foramen ovale. Discussion. Arterial thrombosis is known as unusual thrombosis; this situation requires to rule out associated thrombophilia or other prothrombotic diseases. Protein S deficiency is a rare thrombophilia, which in adults causes venous thrombosis. In the presence of anatomical defects, such as a patent foramen ovale, it can progress to arterial embolism, presenting a picture of paradoxical embolism. The study work of these patients requires imaging that demonstrates the aforementioned defect, as well as the possible origin of the emboli. Management is based on full anticoagulation, treatment of existing thrombotic manifestations, and management of the anatomical defect. Conclusions. Paradoxical embolism should be suspected in case of unusual thrombosis. It requires exhaustive studies based on imaging, and management should consist of anticoagulation and closure of the defect.

Atrial fibrillation with low cardioembolic risk and ischemic cerebrovascular accidents / Fibrilación auricular con riesgo cardioembólico bajo y accidente cerebrovascular isquémico

Abstract Atrial fibrillation is the most prevalent disease in hypertensive patients over the age of 60. Although a large proportion of patients have symptoms related to this arrhythmia, some asymptomatic patients may experience cerebrovascular accidents as the only clinical manifestation. It is very important for clinicians to have a clear understanding of the tools, scales and specific information required for performing an appropriate assessment of patients with atrial fibrillation, in order to prevent its complications. We present the case of a male patient with atrial fibrillation and a low risk of ischemic cardiovascular accidents, whose implanted event monitor showed no evidence of arrhythmias for over one year, and who developed an ischemic CVA in multiple cerebral territories, with subsequent documentation of a thrombus in the left atrial appendage. (Acta Med Colomb 2021; 46. DOI:https://doi.org/10.36104/amc.2021.2006).

Resumen La fibrilación auricular es la enfermedad más prevalente en pacientes hipertensos mayores de 60 años. Si bien una gran proporción de pacientes tiene síntomas relacionados con esta arritmia, algunos pacientes asintomáticos pueden desarrollar accidentes cerebrovasculares como única manifestación clínica. Para el clínico es importante tener un conocimiento claro sobre las herramientas, escalas e información específica para realizar una correcta valoración del paciente con fibrilación auricular, con el objetivo de prevenir las complicaciones relacionadas con esta arritmia. Se presenta el caso de un paciente de sexo masculino con fibrilación auricular y riesgo bajo de accidente cerebrovascular isquémico, portador de monitor de eventos, sin evidencia de arritmia por más de un año, quien desarrolló un ACV isquémico en múltiples territorios cerebrales, con posterior documentación de trombo en la auriculilla izquierda. (Acta Med Colomb 2021; 46. DOI:https://doi.org/10.36104/amc.2021.2006).

Anomalía de Ebstein y aneurisma del seno coronario / Ebstein’s anomaly and coronary sinus aneurysm

Resumen La anomalía de Ebstein es una cardiopatía congénita poco común que se asocia a la presencia de vías de conducción anómalas y episodios de taquicardia supraventricular frecuentes, algunos inestables. La asociación con alteraciones anatómicas del seno coronario es rara y no ha sido reportada. Se presenta el caso de una paciente de 58 años con enfermedad coronaria, anomalía de Ebstein, episodios de taquicardia ortodrómica y aneurisma del seno coronario, a quien se realizó ablación.

Abstract Ebstein’s disease is a congenital cardiomyopathy, with a low prevalence in the general population. This abnormality has been associated with abnormal cardiac conduction problems, one of the most important being the accessory pathways. In the presence of an accessory pathway, frequent supraventricular tachycardias may occur, some of which are poorly tolerated. The association with the anomalies of the coronary sinus is not currently reported. The case of a 58-year-old woman with Ebstein’s disease, episodes of supraventricular tachycardia, and coronary sinus aneurysm undergoing ablation therapy is presented.

Descripción de los pacientes de 80 o más años intervenidos quirúrgicamente en el laboratorio de electrofisiología en un hospital de tercer nivel / Description of patients aged 80 or older undergoing surgery in the electrophysiology lab of a tertiary care hospital

Resumen Introducción: en una unidad de electrofisiología de un hospital de tercer nivel de Manizales, Caldas, se han atendido pacientes en la cuarta edad; sin embargo, existe poca claridad en la literatura sobre las conductas terapéuticas en este grupo etario. Presentamos nuestra experiencia de atención e intervención en pacientes mayores de 80 años entre el 20 de septiembre de 2017 y 7 de octubre de 2019. Métodos: estudio tipo cohorte longitudinal, se recogió información con base en revisión de historias clínicas. Se realizaron seguimientos telefónicos al tercer y sexto mes del procedimiento. Se incluyeron pacientes mayores de 80 años intervenidos de cualquier procedimiento en la sala de electrofisiología. Se excluyeron los pacientes sin información sobre los datos de seguimiento. Resultados: se recogieron datos de 75 pacientes llevados a procedimiento. El 62.7% de los pacientes fueron hombres, las edades oscilaron entre 80 y 95 años. 32.7%, de pacientes con diagnóstico de disfunción sinusal. La comorbilidad más prevalente fue hipertensión arterial (92%). El procedimiento más realizado fue el implante de marcapaso bicameral. La mediana del tiempo de estancia hospitalaria fue de 1 día. EL 70% de los pacientes tuvieron riesgo medio o bajo según la escala CHA2DS2VASc. En el lapso de seis meses se encontró una incidencia acumulada de complicaciones de 4%, con 8% de reconsultas y una mortalidad de 1.3%. Conclusiones: las complicaciones posquirúrgicas, la necesidad y duración de la hospitalización, la tasa de reconsulta y la mortalidad asociada a los procedimientos en este grupo de edad son similares a las observadas en estudios con población menor de 80 años.

Abstract Introduction: fourth age patients have been cared for in the electrophysiology unit of a tertiary care hospital in Manizales, Caldas; however, there is little clarity in the literature regarding therapeutic conduct in this age group. We present our experience of care and intervention in patients over the age of 80 between September 20, 2017 and October 7, 2019. Methods: a longitudinal cohort study in which data was collected from a chart review. Telephone follow up was performed three and six months after the procedure. Patients over the age of 80 who had undergone any procedure in the electrophysiology lab were included. Patients without follow up information were excluded. Results: data were collected on 75 patients undergoing a procedure: 62.7% of the patients were men, ages ranged from 80 to 95, and 32.7% of the patients had a diagnosis of sinus dysfunction. The most prevalent comorbidity was arterial hypertension (92%). The most frequently performed procedure was dual chamber pacemaker implantation. The median hospital stay was one day. Seventy percent of the patients had a medium or low risk according to the CHA2DS2-VASc scale. Over a six-month period, a 4% cumulative incidence of complications was found, with 8% reconsultation and 1.3% mortality. Conclusions: postsurgical complications, the need for and length of hospitalization, the rate of reconsultation and the mortality associated with procedures in this age group are similar to those seen in studies of populations under 80 years old.

Impact of frailty and viral load on acute kidney injury evolution in patients affected by Coronavirus Disease 2019.

This paper describes the main characteristics of coronavirus diseases 2019 (COVID-19) patients suffering from acute kidney injury (AKI) assisted at a high complexity clinic in Barranquilla, Colombia. The patients included in this study (n = 48) were those with a positive diagnosis of COVID-19 confirmed by polymerase chain reaction detection of severe acute respiratory syndrome coronavirus 2, who had developed AKI during their hospital stay. Serum and urine parameters, as well as patient's viral load and clinical frailty scale (CFS) were recorded. A statistical analysis of the recorded parameters, such as comparisons, and correlations between variables of interest, were explored. The prevalence of COVID-19 induced AKI was 41%, being the majority of them classified as AKI network classification 3, with a renal replacement therapy requirement of 29%, and an associated mortality of 73%. AKI patients' mortality showed a significant positive correlation (33%) with patients' CFS score but not with their viral load. COVID-19 induced AKI significantly correlated with patients' frailty status but not to their viral load.

Reporte de cuatro casos COVID-19 hospitalizados en unidad de cuidados intensivos en una institución hospitalaria en Barranquilla, Colombia / Original article: Case-Serie of 4 COVID-19 patients hospitalized in an intensive care unit in a hospital institution in Barranquilla, Colombia

Resumen Presentar una serie de casos de COVID-19 con requerimiento de ingreso a Unidad de Cuidados Intensivos. La información fue tomada de las historias clínicas, y su evaluación y diagnóstico fue realizado mediante estudios paraclínicos en sangre, orina, PCR e imágenes diagnósticas en 4 pacientes con diferentes comorbilidades y nexo epidemiológico presente para desarrollo de la enfermedad. Los cuatro casos fueron manejados con cloroquina 300 mg vía oral, cada 12 horas, y azitromicina 1 gr vía oral, cada 24 horas, durante 5 días, sin complicaciones ni toxicidad asociada. El caso 1 desarrolló falla orgánica múltiple, incluyendo injuria renal aguda con una estancia en UCI de 4 días antes de su fallecimiento, mientras los casos 2, 3 y 4 tuvieron una evolución favorable y fueron dados de alta de UCI. Se requieren estudios multicéntricos rápidos que orienten científicamente hacia un mejor abordaje diagnóstico y manejo, en el contexto de una enfermedad con un comportamiento clínico-epidemiológico que debe estudiarse en profundidad y que probablemente cobrará muchas vidas; además, debido a la ausencia de pruebas diagnósticas rápidas, la utilización de una clasificación basada en la severidad de lesiones radiológicas llamada CO-RADS (Covid-19 Imaging Reporting and Data System) podría ser de gran importancia para instalar de manera temprana los tratamientos farmacológicos disponibles y la asistencia respiratoria mecánica precoz.

Abstract To present a COVID-19 case series with clinical admission criteria to Intensive Care Unit. Patients information was obtained from medical records, and daily clinical evaluation whereas diagnosis was carried out through paraclinical studies in blood, urine, PCR and diagnostic images in 4 patients with different comorbidities and epidemiological link for the development of COVID-19. All four cases were managed with chloroquine 300 mg orally every 12 hours and azithromycin orally every 24 hours for 5 days without complications or associated toxicity. The case 1 developed multiple organ failure, including acute kidney injury with an ICU stay of 4 days before his death, while cases 2, 3 and 4 had a favorable evolution and were discharged from the ICU. Rapid multicenter studies are required to scientifically guide a better diagnostic and management approach, in the context of a disease with a clinical-epidemiological behavior that must be studied in depth and will probably take many lives. In addition, due to the absence of sufficiently rapid tests, the use of a classification based on the severity of radiological lesions called CO-RADS (Covid-19 Imaging Reporting and Data System) could be of great importance to install available pharmacological treatments early and early mechanical respiratory support.

Impact of umbilical cord length on fetal circulatory system by Doppler assessment.

INTRODUCTION: Numerous studies have revealed the impact of umbilical cord (UC) length on fetal perfusion; abundant data implicate abnormal UC length to neurological delay and subsequent poor prognoses for fetuses and newborns. Indeed, our group previously developed theoretical approximations that contributed to formulas capable of explaining the impact of UC length on cardiac output. METHODS: We performed an observational study that measured the pulsatility index and flow velocity in umbilical arteries. A special Doppler measured proximal and distal indexes in both arteries. After birth, medical staff measured complete UC length. We obtained maternal and neonatal outcomes from clinical records. RESULTS: Our study enrolled 20 pregnant mothers. We found that flow velocities in the two edges were different: fetal edges exhibited greater velocity in the majority of cases; but, when we compared pressure differentials (ΔP), the pulsatility index was significantly related to umbilical cord length. CONCLUSIONS: Fetal perfusion, welfare, and viability are related to UC function as the conveyor of all fetal volemia. Excessive UC length affects cardiac dynamics and increases peripheral vascular resistance. Further studies could validate routine use of the differential proximal and distal measurements proposed in this article, and their implications in in utero fetal heart function. We also hope that early diagnosis or UC alterations could alert neonatologists and obstetricians to clinical conditions of the fetus.

Asystole in an older patient with recurrent falls. case report

ABSTRACT Introduction: Recurrent falls are a usual problem in older patients. It is therefore important to learn how to differentiate a pathological or syncopal episode from a simple stumbling fall, especially in patients who have limitations for communicating clearly and are poorly understood, in general terms, during the medical consultation. Implantable loop recorders (ILR) have been used as an investigation tool in selected cases of recurrent falls in older patients. Consequently, this case report aims to describe its usefulness in this type of patients. Case presentation: An 87-year-old female patient, hypertensive, with a history of recent stroke and frequent falls -referred to as stumbling-, received an implantable loop recorder due to atrial fibrillation. During one follow-up appointment, a 36-second pause related to a fall was documented, so a bicameral pacemaker was implanted. Conclusions: Evaluating repeated falls in older patients is complex; it must be done in detail to rule out syncopal episodes. Implantable devices to diagnose arrhythmic causes are useful and allow achieving accurate diagnoses and establish specific behaviors aimed at improving the quality of life of patients.

RESUMEN Introducción. Las caídas frecuentes son un problema común en pacientes de la tercera y la cuarta edad, por tanto es importante saber diferenciar cuando se trata de un evento patológico o sincopal, y cuando es un simple tropiezo, sobre todo en pacientes que tienen limitaciones para comunicarse de forma clara y son poco entendidos en términos generales durante la consulta médica. Los monitores de eventos cardiacos pueden ser usados en casos seleccionados de caídas frecuentes en adultos mayores para determinar las posibles causas de estos eventos, por lo que el presente reporte de caso pretende mostrar cuál es su utilidad en un paciente con caídas no sincopales a repetición. Presentación del caso. Paciente femenina de 87 años, hipertensa, con evento cerebrovascular reciente e historia de caídas a repetición referidas como tropiezos, a quien se le implantó un dispositivo diagnóstico de fibrilación auricular. En uno de los controles se observó pausa de 36 segundos relacionada con episodio de caída, por lo que se implantó un marcapasos bicameral. Conclusiones. La evaluación de caídas a repetición en pacientes mayores es compleja y debe realizarse de forma detallada para descartar síncope. El uso de monitores de eventos cardiacos para la identificación de causas arrítmicas de estos eventos permite diagnósticos certeros, con lo que a su vez es posible establecer tratamientos específicos que mejoren la calidad de vida de los pacientes.

Photonic Crystal Characterization of the Cuticles of Chrysina chrysargyrea and Chrysina optima Jewel Scarab Beetles.

A unified description involving structural morphology and composition, dispersion of optical constants, modeled and measured reflection spectra and photonic crystal characterization is devised. Light reflection spectra by the cuticles of scarab beetles (Chrysina chrysargyrea and Chrysina optima), measured in the wavelength range 300-1000 nm, show spectrally structured broad bands. Scanning electron microscopy analysis shows that the pitches of the twisted structures responsible for the left-handed circularly polarized reflected light change monotonically with depth through the cuticles, making it possible to obtain the explicit depth-dependence for each cuticle arrangement considered. This variation is a key aspect, and it will be introduced in the context of Berreman's formalism, which allows us to evaluate reflection spectra whose main features coincide in those displayed in measurements. Through the dispersion relation obtained from the Helmholtz's equation satisfied by the circular components of the propagating fields, the presence of a photonic band gap is established for each case considered. These band gaps depend on depth through the cuticle, and their spectral positions change with depth. This explains the presence of broad bands in the reflection spectra, and their spectral features correlate with details in the variation of the pitch with depth. The twisted structures consist of chitin nanofibrils whose optical anisotropy is not large enough so as to be approached from modeling the measured reflection spectra. The presence of a high birefringence substance embedded in the chitin matrix is required. In this sense, the presence of uric acid crystallites through the cuticle is strongly suggested by frustrated attenuated total reflection and Raman spectroscopy analysis. The complete optical modeling is performed incorporating the wavelength-dependent optical constants of chitin and uric acid.

Uso de los sistemas de presión negativa en el tratamiento de infecciones asociadas a dispositivos: ''una vieja terapia con un uso novedoso'' / Use of negative pressure systems for the management of infections associated to devices: ''an old therapy with a new use''

Resumen Introducción: El cuidado de los pacientes con infecciones asociadas al dispositivo sin endocarditis, incluye: la extracción completa y la realización de capsulectomía para evitar la reinfección. El uso de nuevos elementos como el sistema de la presión negativa es una terapia novedosa que ha demostrado disminuir: los tiempos de recuperación, el tiempo de estancia intrahospitalaria, la necesidad de nuevas intervenciones por sangrado o lavado y el tiempo de espera para un nuevo implante. Nuestro objetivo es describir la experiencia de un centro de cuarto nivel, en el manejo de las infecciones asociadas a los dispositivos sin endocarditis, con el uso de la terapia de presión negativa como parte del manejo. Metodología: Se realizó una descripción retrospectiva de la experiencia en el manejo de la terapia de presión negativa en pacientes con infecciones asociadas a dispositivo, en un centro de cuarto nivel. Se exponen cinco casos, a los que se les realizó: la extracción completa del dispositivo, la capsulectomía anterior y posterior, el lavado quirúrgico y el implante de la terapia con presión negativa. Conclusión: La experiencia presentada demuestra que el uso de la terapia de presión negativa es un protocolo de tratamiento novedoso, que en nuestros pacientes con infección asociada a dispositivo sin endocarditis, es segura y de fácil utilización.

Abstract Introduction: Care for patients with infections associated to the device without endocarditis include complete extraction and performing a capsulectomy to avoid reinfection. The use of new elements, such as the negative pressure system, is a new therapy that has shown to reduce recovery time, inpatient stay, need of new interventions due to bleeding or washing and waiting time for a new implant. The goal is to describe the experience of a fourth level centre for managing infections associated with devices without endocarditis using a negative pressure system as part of the therapy. Methods: Descriptive retrospective study of the experience of negative pressure therapy for managing patients with device-related infections at a fourth level centre. Five cases are exposed where complete removal of the device, anterior and posterior capsulectomy, surgical washing and negative pressure therapy were performed. Conclusion: Presented experience shows that the use of negative pressure therapy is a new therapy protocol that is safe and easy for managing our patients with an infection associated to the device without endocarditis.

Masa en cuello secundaria a electrodo de estimulación cardiaca abandonado / Neck mass secondary to an abandoned pacing lead

Mujer de 70 años de edad, con historia de un electrodo de estimulación cardiaca abandonado, que genera: un trastorno de la deglución y una deformidad estética que la hacen consultar en múltiples oportunidades. A pesar de que se planteó la opción del retiro quirúrgico, se logró una extracción endovascular por la tracción de un electrodo. Describimos la utilidad del eco intracardiaco y el catéter ENSnare®, para la extracción de los electrodos en este tipo de casos.

70-year-old woman with a history of an abandoned pacing lead who developed a deglutition disorder and an aesthetic deformity that made her consult in multiple specialties. Even though surgical removal was considered, endovascular extraction was accomplished with the traction of the lead. We describe the usefulness of the intracardiac echocardiography and the ENSnare® catheter for this type of lead extractions.

Fuerza aplicada por el personal de salud sobre un simulador del cartílago cricoides durante la realización de la maniobra de Sellick en la intubación de secuencia rápida / Pressure applied by the healthcare staff on a cricoid cartilage simulator during Sellick’s maneuver in rapid sequence intubation

Antecedentes: La maniobra de Sellick o fuerza cricoidea es una estrategia utilizada para prevenir broncoaspiración durante la secuencia rápida de intubación. Algunos estudios han descrito que la fuerza necesaria para que la maniobra sea adecuada es de 2,5 a 3,5 kg. Este estudio tuvo como objetivo determinar cuál es la fuerza ejercida (en kilogramos) sobre un simulador del cartílago cricoides por profesionales de la salud. Metodología: Estudio observacional de corte transversal. Los participantes fueron personal de salud del Hospital Universitario San José de Popayán y asistentes al Congreso Nacional de Anestesiología S.C.A.R.E. 2011, los cuales fueron seleccionados a conveniencia. Cada participante ejecutó 3 intentos de realización de la maniobra sobre el simulador. Resultados:Se recolectaron datos de 156 participantes. La fuerza global media ejercida en el primer, segundo y tercer intento de realización fue de 2,70, 2,71 y 2,73 kg, respectivamente. Tras el ajuste multivariante, el género masculino presentó influencia en la mayor aplicación de fuerza en el primer intento de realización de la maniobra. No se encontró asociación con otras variables como la experiencia de trabajo o el grado de entrenamiento. Conclusiones:La fuerza ejercida por los participantes en el estudio durante el primer intento fue de 2,7 kg. La mayoría de los sujetos en estudio realizaron la maniobra de Sellick con una fuerza inadecuada en el primer intento. Únicamente el género masculino afecta la fuerza realizada por los profesionales en el primer intento de realización de la maniobra.

Bacfeground:Sellick's maneuver or cricoid pressure is a strategy used to prevent bronchoas-piration during the rapid intubation sequence. Several studies have described that the forcerequired for an adequate maneuver is of 2.5-3.5 kg. The purpose of this paper was to determine the force applied (in kilograms) on a cricoid cartilage simulator by the health care professionals. Methodology:Observational cross-section trial. The participants were the healthcare professionals at the San José University Hospital in Popayán and participants at the National Congress of Anesthesiology - S.C.A.R.E. 2011, who were conveniently selected. Every participant made three attempts to apply the maneuver on the simulator. Results: Data from 156 participants were collected. The mean global pressures applied in the first, second and third attempts were 2.70, 2.71 and 2.73 kg, respectively. Following a multivariate adjustment, males exhibited a higher force at the first attempt to do the maneuver. No association was found to other variables, such as labor experience or the training level. Conclusions:The pressure applied by the participants in the trial during the first attempt was 2.7 kg. Most of the subjects in the trial did Sellick's maneuver applying an inadequate pressure in their first attempt. Only males exerted an overpressure in their first attempt todo the maneuver.

Scattering of light by colloidal aluminosilicate particles produces the unusual sky-blue color of Río Celeste (Tenorio volcano complex, Costa Rica).

Río Celeste (Sky-Blue River) in Tenorio National Park (Costa Rica), a river that derives from the confluence and mixing of two colorless streams--Río Buenavista (Buenavista River) and Quebrada Agria (Sour Creek)--is renowned in Costa Rica because it presents an atypical intense sky-blue color. Although various explanations have been proposed for this unusual hue of Río Celeste, no exhaustive tests have been undertaken; the reasons hence remain unclear. To understand this color phenomenon, we examined the physico-chemical properties of Río Celeste and of the two streams from which it is derived. Chemical analysis of those streams with ion-exchange chromatography (IC) and inductively coupled plasma atomic emission spectroscopy (ICP-OES) made us discard the hypothesis that the origin of the hue is due to colored chemical species. Our tests revealed that the origin of this coloration phenomenon is physical, due to suspended aluminosilicate particles (with diameters distributed around 566 nm according to a lognormal distribution) that produce Mie scattering. The color originates after mixing of two colorless streams because of the enlargement (by aggregation) of suspended aluminosilicate particles in the Río Buenavista stream due to a decrease of pH on mixing with the acidic Quebrada Agria. We postulate a chemical mechanism for this process, supported by experimental evidence of dynamic light scattering (DLS), zeta potential measurements, X-ray diffraction and scanning electron microscopy (SEM) with energy-dispersive spectra (EDS). Theoretical modeling of the Mie scattering yielded a strong coincidence between the observed color and the simulated one.

Closed equation for the normal incidence reflectance of thin films on absorbing substrates.

The optical constants of thin films can be obtained from inversion of spectrophotometric measurements by using minimization gradient methods. The computational approach of these minimization methods requires closed compact formulas for reflectance and/or transmittance. For normal incidence closed compact formulations for the direct transmittance, both for thin films on transparent or absorbing substrates, and for the reflectance of thin films on transparent substrates, are available in the literature. We report here a closed compact formula to evaluate reflectance spectra of thin films on absorbing substrates, and it is shown that for vanishing substrate absorption this new, to the best of our knowledge, approach gives the same results obtained from the formulation corresponding to thin films supported by transparent substrates.

Understanding the relationship of maternal health behavior change and intervention strategies in a Nicaraguan NGO network.

Few studies of community interventions examine independent effects of investments in: (1) capital (i.e., physical, human and social capital), and (2) management systems (e.g., monitoring and evaluation systems (M&E)) on maternal and child health behavior change. This paper does this in the context of an inter-organizational network. In Nicaragua, international non-governmental organizations (NGOs) and local NGOs formed the NicaSalud Federation. Using Lot Quality Assurance Sampling (LQAS), 14 member organizations took baselines measures of maternal safe motherhood and child health behavior indicators during November 1999 and August 2000, respectively, and final evaluation measures in December 2001. In April 2002, retrospective interviews were conducted with supervisors and managers in the 14 organizations to explore changes made to community health strategies, factors associated with the changes, and impacts they attributed to participating in NicaSalud. Physical capital (density of health huts), human capital (density and variety of paramedical personnel) and social capital (density of health committees) were associated with pregnant women attending antenatal care (ANC) 3+ times, and/or retaining ANC cards. The variety of paramedic personnel was also associated with women making post-partum visits to clinics. Physical capital (density of health huts) and social capital (density of health committees and mothers' clubs) were associated with child diarrhea case management indicators. One safe motherhood indicator (delivery of babies by a clinician) was not associated with intervention strategies. At the management level, NicaSalud's training of members to use LQAS for M&E was associated with the number of strategic and tactical changes they subsequently made to interventions (organizational learning). Organizational learning was related to changes in maternal and child health behaviors of the women (including changes in the proportion using post-partum care). As the latter result would not have occurred without NicaSalud, we conclude that this inter-organizational network provided added value by instigating organizational learning.

Evaluacion de la calidad de aguas residuales de la planta de tratamiento de Alba Rancho (SEMAPA) con fines de riego / sss

Si bien las aguas residuales de SEMAPA en este momento estan coadyuvando al riego de 400 has, en la Maica, Alba Rancho y Montecanto. Las caracteristicas fisicas, cuyo uso final es el riego. Obviamente estas aguas tienen un uso restringido ya que supuestamente solo se utilizan para el riego de masiz forrajero (Zea mais), alfa alfa (Medicago sativa) y Batillo (Lolium sp). Agropiro crestado. Los analisis hechos en laboratorio de aguas no contempla muchos parametros, segun el estudio de sales solubles podemos concluir que el agua de la planta de tratamiento de Alba Rancho tiene una calificacion "Condicional", Agua Altamente salina (C3) no siendo aptos para suelos cuyo drenaje es deficiente, lo cual involucra un adecuado manejo del suelo y la eleccion de especies o forrajes tolerante...

Incidencia de VPH en trabajadoras sexuales en el Cantón La Maná y su relación con cáncer

El presente estjudio se realiza, con el fin de investigar la incidencia de VPH en 40 trabajadoras sexuales del Cantón La Maná, quienes acuden a control profiláctico. La edad de las pacientes oscila entre los 18 y 44 años, con el mayor porcentaje de ellas en edad fertil. La incidencia del VPH en trabajadoras sexuales, alcanza el 7.5 por ciento el grupo etáreo con mayor incidencia es el comprendido entre 18 y 26 años, con 3 pacientess con VPH. En relación a la clase citológica vemos que el VPH se presenta en una trabajadora con clase II y en 2 trabajadores sexuales con clase III...

Evaluación del grado de acidez de las lluvias en la Ciudad de La Paz

Durante los meses de noviembre de 1992 a marzo de 1993, período de lluvias predominante, se llevó a cabo un estudio enfocado a la medición del grado de acidez del agua de lluvia, mediante la técnica de deposito total, cuyo parámetro indicador es el ph, en la ciudad de La Paz. Se analizaron ocho parametros como conductividad, sulfatos, nitratos, acidez total, alcalinidad total y plomo