Atrial activation during sinus rhythm in patients with rheumatic and non-rheumatic paroxysmal atrial fibrillation. Frequency-domain analysis using signal-averaged electrocardiography

OBJECTIVE: Using P-wave signal-averaged electrocardiography, we assessed the patterns of atrial electrical activation in patients with idiopathic atrial fibrillation as compared with patterns in patients with atrial fibrillation associated with structural heart disease. METHODS: Eighty patients with recurrent paroxysmal atrial fibrillation were divided into 3 groups as follows: group I - 40 patients with atrial fibrillation associated with non-rheumatic heart disease; group II - 25 patients with rheumatic atrial fibrillation; and group III - 15 patients with idiopathic atrial fibrillation. All patients underwent P-wave signal-averaged electrocardiography for frequency-domain analysis using spectrotemporal mapping and statistical techniques for detecting and quantifying intraatrial conduction disturbances. RESULTS: We observed an important fragmentation in atrial electrical conduction in 27% of the patients in group I, 64% of the patients in group II, and 67% of the patients in group III (p=0.003). CONCLUSION: Idiopathic atrial fibrillation has important intraatrial conduction disturbances. These alterations are similar to those observed in individuals with rheumatic atrial fibrillation, suggesting the existence of some degree of structural involvement of the atrial myocardium that cannot be detected with conventional electrocardiography and echocardiography.

Cultural circuits of climate change in U.K. broadsheet newspapers, 1985–2003

This article argues for a cultural perspective to be brought to bear on studies of climate change risk perception. Developing the “circuit of culture” model, the article maintains that the producers and consumers of media texts are jointly engaged in dynamic, meaning-making activities that are context-specific and that change over time. A critical discourse analysis of climate change based on a database of newspaper reports from three U.K. broadsheet papers over the period 1985–2003 is presented. This empirical study identifies three distinct circuits of climate change—1985–1990, 1991–1996, 1997–2003—which are characterized by different framings of risks associated with climate change. The article concludes that there is evidence of social learning as actors build on their experiences in relation to climate change science and policy making. Two important factors in shaping the U.K.’s broadsheet newspapers’ discourse on “dangerous” climate change emerge as the agency of top political figures and the dominant ideological standpoints in different newspapers.

Detection of incipient left ventricular hypertrophy in mild to moderate arterial hypertension with normal electrocardiogram and echocardiogram: a new use for signal-averaged electrocardiography

OBJECTIVE: To assess signal-averaged electrocardiogram (SAECG) for diagnosing incipient left ventricular hypertrophy (LVH). METHODS: A study with 115 individuals was carried out. The individuals were divided as follows: GI - 38 healthy individuals; GII - 47 individuals with mild to moderate hypertension and normal findings on echocardiogram and ECG; and GIII - 30 individuals with hypertension and documented LVH. The magnitude vector of the SAECG was analyzed with the high-pass cutoff frequency of 40 Hz through the bidirectional four-pole Butterworth high-pass digital filter. The mean quadratic root of the total QRS voltage (RMST) and the two-dimensional integral of the QRS area of the spectro-temporal map were analyzed between 0 and 30 Hz for the frequency domain (Int FD), and between 40 and 250 Hz for the time domain (Int TD). The electrocardiographic criterion for LVH was based on the Cornell Product. Left ventricular mass was calculated with the Devereux formula. RESULTS: All parameters analyzed increased from GI to GIII, except for Int FD (GII vs GIII) and RMST log (GII vs GIII). Int TD showed greater accuracy for detecting LVH with an appropriate cutoff > 8 (sensitivity of 55%, specificity of 81%). Positive values (> 8) were found in 56.5% of the G II patients and in 18.4% of the GI patients (p< 0.0005). CONCLUSION: SAECG can be used in the early diagnosis of LVH in hypertensive patients with normal ECG and echocardiogram.

Metabolismo de fosfolípidos, señal de calcio y sus implicancias en la diferenciación de Trypanosoma cruzi. Phospholipids metabolism, calcium signal and its implications in the differentiation of Trypanosoma cruzi.

Trypanosoma cruzi es un protozoo primitivo agente causal de la enfermedad de Chagas. La transmisión de esta enfermedad depende tanto del desarrollo y de la diferenciación del microorganismo en el intestino del vector. Las diferentes formas del parásito se han adaptado a una serie de condiciones impuestas por los distintos ambientes en donde debió habitar. Esta capacidad de sobrevivir a medios externos tan variados está dada por la diversidad en las vías de transducción de señales en el parásito. T. cruzi se multiplica y diferencia (metaciclogénesis) en el recto de los triatominos. A este nivel, los parásitos se enfrentan a un incremento en la osmolaridad causado por un elevado contenido de NaCl en la orina. En nuestro laboratorio se observó que diferentes estímulos son capaces de producir incrementos en los niveles de IP3 y de Ca2+ intracelular, consecuencia de la activación del ciclo del inositol fosfato, y activación de fosfolipasa D (PLD) y fosfatidilinositol 3 quinasa (PI3K). En un medio carente de Na+ los epimastigotes estimulados con carbacol, mostraron una señal de calcio disminuida mientras que la acumulación de IP3 no se modificó. Además, esta señal se incrementó en presencia de PMA, activador de proteína quinasa C, mientras que la acumulación de IP3 se anuló completamente. Estos resultados indujeron a pensar en un mecanismo alternativo y/o paralelo a IP3 en la liberación de Ca2+, en el cual la presencia de un intercambiador Na+/H+ favorecería la liberación del ion desde organelas acídicas. Es conocido que la señal de calcio es requerida para la metaciclogénesis, y que esta señal es independiente del Ca2+ extracelular (Lammel y col. 1996, Marchesini y col., 2002). De este modo se propone que "los epimastigotes de T. cruzi utilizan como elementos conservados a lo largo de la evolución a los elementos del ciclo del inositol fosfato, uno de los sistemas de transducción de señales más antiguo, para responder a estímulos que inducen la diferenciación del parásito". Por lo tanto, para el desarrollo de este proyecto se propone determinar la presencia de un RcIP3 en epimastigotes y conocer su compromiso en la liberación de Ca2+ desde reservorios intracelulares. Además, establecer si un intercambiador Na+/H+ en membrana de acidocalcisomas estaría relacionado con la señal de calcio intracelular y su posible regulación por proteina quinasa C y A (PKC y PKA, respectivamente). Por otro lado, para dilucidar la implicancia de estos mecanismos en el proceso de metaciclogénesis, se propone estudiar la activación del intercambiador Na+/H+ y la señal de calcio en condiciones de hiperosmolaridad, tal como ocurre en el recto del triatomino. Ademas, ya que el proceso de diferenciación involucra una reorganización de los microtubulos del citoesqueleto se pretende estudiar el compromiso del metabolismo de fosfolípidos y tubulina en procesos que contribuyen a la inducción de la metaciclogenesis. El alcance de los objetivos mencionados ayudará a dilucidar la presencia de componentes tales como RcIP3 y el intercambiador Na+/H+ involucrados en la señalización del ion bivalente. Por otro lado, se espera demostrar que los isotipos de tubulina encontrados en T. cruzi cambien en cantidad relativa y nivel de expresión cuando los epimastigotes sean estimulados con posibles inductores de la diferenciación. Además, se espera observar simultáneamente un aumento en la actividad de dos enzimas relacionadas con la reorganización de microtúbulos: PI-3K y PLD. En tal caso, y para comprobar su implicancia en el proceso, se espera que la inhibición de tales enzimas sea capaz de revertir el efecto producido por los estímulos. Como la PLC se expresa principalmente en las forma epimastigotes mas que en los tripomastigotes (forma infectiva), la señal de Ca2+ inducida por IP3 se relacionaría con la capacidad del parásito para responder a ciertos cambios de pH y osmolaridad que enfrenta el microorganismo en el tracto digestivo del insecto vector.

Investigating the long term planning framework for the Galway Bay community from climate change.

This research looked at the scientific evidence available on climate change and in particular, projections on sea level rise which ranged from 0.5m to 2m by the end of the century. These projections were then considered in an Irish context. A review of current policy in Ireland revealed that there was no dedicated Government policy on climate change or coastal zone management. In terms of spatial planning policy, it became apparent that there was little or no guidance on climate change either at a national, regional or local level. Therefore, to determine the likely impacts of sea level rise in Ireland based on current spatial planning practice and policy, a scenario-building exercise was carried out for two case study areas in Galway Bay. The two case study areas were: Oranmore, a densely populated town located to the east of Inner Galway Bay; and Tawin Island, a rural dispersed community, located to the south east of Inner Galway Bay. A ‘best’ and ‘worse’ case scenario was envisaged for both areas in terms of sea level rise. In the absence of specific climate change policies it was projected that in the ‘best’ case scenario of 0.5m sea level rise, Tawin Island would suffer serious and adverse impacts while Oranmore was likely to experience slight to moderate impacts. However, in the ‘worse’ case scenario of a 2m sea level rise, it was likely that Tawin Island would be abandoned while many houses, businesses and infrastructure built within the floodplain of Oranmore Bay would be inundated and permanently flooded. In this regard, it was the author’s opinion that a strategic and integrated climate change policy and adaptation plan is vital for the island of Ireland that recognises the importance of integrated land use and spatial planning in terms of mitigation and adaptation to climate change.

Flood analysis of the clare river catchment considering traditional factors and climate change

The main objective of this thesis on flooding was to produce a detailed report on flooding with specific reference to the Clare River catchment. Past flooding in the Clare River catchment was assessed with specific reference to the November 2009 flood event. A Geographic Information System was used to produce a graphical representation of the spatial distribution of the November 2009 flood. Flood risk is prominent within the Clare River catchment especially in the region of Claregalway. The recent flooding events of November 2009 produced significant fluvial flooding from the Clare River. This resulted in considerable flood damage to property. There were also hidden costs such as the economic impact of the closing of the N17 until floodwater subsided. Land use and channel conditions are traditional factors that have long been recognised for their effect on flooding processes. These factors were examined in the context of the Clare River catchment to determine if they had any significant effect on flood flows. Climate change has become recognised as a factor that may produce more significant and frequent flood events in the future. Many experts feel that climate change will result in an increase in the intensity and duration of rainfall in western Ireland. This would have significant implications for the Clare River catchment, which is already vulnerable to flooding. Flood estimation techniques are a key aspect in understanding and preparing for flood events. This study uses methods based on the statistical analysis of recorded data and methods based on a design rainstorm and rainfall-runoff model to estimate flood flows. These provide a mathematical basis to evaluate the impacts of various factors on flooding and also to generate practical design floods, which can be used in the design of flood relief measures. The final element of the thesis includes the author’s recommendations on how flood risk management techniques can reduce existing flood risk in the Clare River catchment. Future implications to flood risk due to factors such as climate change and poor planning practices are also considered.

Modern climate change in Georgia. Radiatively active small atmospheric admixtures

წიგნში წარმოდგენილია საქართველოში ზოგიერთი ოპტიკურად აქტიური მცირე ატმოსფერული მინარევის მრავალწლიური კვლევის შედეგები. წარმოდგენილია მონაცემები C02, CHx, S02 და აეროზოლების ანთროპოგენური ემისიების შესახებ. დაწვრილებითაა შესწავლილი აეროზოლების თვლადი კონცენტრაციის ვერტიკალური განაწილება ტროპოსფეროში საქართველოს სხვადასხვა რეგიონისთვის. ჩატარებულია ოზონის საერთო რაოდენობის, ატმოსფერული აეროზოლების ოპტიკური სიმკვრის და სხვა ნაერთების გრძელვადიანი ვარიაცების დეტალური ანალიზი. წარმოდგენილია ზოგიერთი ნაერთის გავლენის თეორიული შეფასება საქართველოში მზის პირდაპირი და გაბნეული რადიაციის რეჟიმზე.

Assessment of touristical-recreation potential of Georgia on background regional climate change

The determination of the climatic potential of tourism to Tbilisi (the capital of Georgia) into the correspondence with that frequently utilized in other countries of the “tourism climate index” is carried out.

Tourism Climate Index in Batumi

ნაშრომში მოცემულია ბათუმისათვის ტურიზმის კლიმატური პოტენციალის შეფასება სხვადასხვა ქვეყანაში ხშირად ხმარებული “ტურიზმის კლიმატური ინდექსის” შესაბამისად

Tourism Climate Index in Tbilisi

ნაშრომში მოცემულია თბილისისათვის ტურიზმის კლიმატური პოტენციალის შეფასება სხვადასხვა ქვეყანაში ხშირად ხმარებული “ტურიზმის კლიმატური ინდექსის” შესაბამისად.

On the provision of global public goods : experimental evidence on climate change mitigation issues

Magdeburg, Univ., Fak. für Wirtschaftswiss., Diss., 2011

Ground penetrating radar signal processing for landmine detection

Ground penetrating radar; landmine; background clutter removal, buried targets detecting

Modular analysis of signal transduction networks

Modularity, signaling networks, sytems biology

Modulation of [My]-opioid receptor signal transduction and endocytosis by ADP-ribosylation factor proteins

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2010