State-Uncertainty preferences and the Risk Premium in the Exchange rate market

This paper introduces state-uncertainty preferences into the Lucas (1982) economy, showing that this type of preferences helps to explain the exchange rate risk premium. Under these preferences we can distinguish between two factors driving the exchange rate risk premium: “macroeconomic risk” and “the risk associated with variation in the private agents’ perception on the level of uncertainty”. State-uncertainty preferences amount to assuming that a given level of consumption will yield a higher level of utility the lower is the level of uncertainty perceived by consumers. Furthermore, empirical evidence from three main European economies in the transition period to the euro provides empirical support for the modelForecasting, subspace methods, combining forecasts.

State-Uncertainty preferences and the Risk Premium in the Exchange rate market

This paper introduces state-uncertainty preferences into the Lucas (1982) economy, showing that this type of preferences helps to explain the exchange rate risk premium. Under these preferences we can distinguish between two factors driving the exchange rate risk premium: “macroeconomic risk” and “the risk associated with variation in the private agents’ perception on the level of uncertainty”. State-uncertainty preferences amount to assuming that a given level of consumption will yield a higher level of utility the lower is the level of uncertainty perceived by consumers. Furthermore, empirical evidence from three main European economies in the transition period to the euro provides empirical support for the modelRisk premium, taste shocks, fundamental uncertainty.

Transmural versus non-transmural in situ electrical impedance spectrum for healthy, ischemic, and healed myocardium

Electrical properties of myocardial tissue are anisotropic due to the complex structure of the myocardial fiber orientation and the distribution of gap junctions. For this reason, measured myocardial impedance may differ depending on the current distribution and direction with respect to myocardial fiber orientation and, consequently, according to the measurement method. The objective of this study is to compare the specific impedance spectra of the myocardium measured using two different methods. One method consisted of transmural measurements using an intracavitary catheter and the other method consisted of nontransmural measurements using a four-needle probe inserted into the epicardium. Using both methods, we provide the in situ specific impedance spectrum (magnitude and phase angle) of normal, ischemic, and infarcted pig myocardium tissue from 1 kHz to 1 MHz. Magnitude spectra showed no significant differences between the measurement techniques. However, the phase angle spectra showed significant differences for normal and ischemic tissues according to the measurement technique. The main difference is encountered after 60 min of acute ischemia in the phase angle spectrum. Healed myocardial tissue showed a small and flat phase angle spectrum in both methods due to the low content of cells in the transmural infarct scar. In conclusion, both transmural and nontransmural measurements of phase angle spectrum allow the differentiation among normal, ischemic, and infarcted tissue.Peer Reviewe

Recognition of fibrotic infarct density by the pattern of local systolic-diastolic myocardial electrical impedance

Myocardial electrical impedance is a biophysical property of the heart that is influenced by the intrinsic structural characteristics of the tissue. Therefore, the structural derangements elicited in a chronic myocardial infarction should cause specific changes in the local systolic-diastolic myocardial impedance, but this is not known. This study aimed to characterize the local changes of systolic-diastolic myocardial impedance in a healed myocardial infarction model. Six pigs were successfully submitted to 150 min of left anterior descending (LAD) coronary artery occlusion followed by reperfusion. 4 weeks later, myocardial impedance spectroscopy (1–1000 kHz) was measured at different infarction sites. The electrocardiogram, left ventricular (LV) pressure, LV dP/dt, and aortic blood flow (ABF) were also recorded. A total of 59 LV tissue samples were obtained and histopathological studies were performed to quantify the percentage of fibrosis. Samples were categorized as normal myocardium (50%). Resistivity of normal myocardium depicted phasic changes during the cardiac cycle and its amplitude markedly decreased in dense scar (18 ± 2 ·cm vs. 10 ± 1 ·cm, at 41 kHz; P < 0.001, respectively). The mean phasic resistivity decreased progressively from normal to heterogeneous and dense scar regions (285 ± 10 ·cm, 225 ± 25 ·cm, and 162 ± 6 ·cm, at 41 kHz; P < 0.001 respectively). Moreover, myocardial resistivity and phase angle correlated significantly with the degree of local fibrosis (resistivity: r = 0.86 at 1 kHz, P < 0.001; phase angle: r = 0.84 at 41 kHz, P < 0.001). Myocardial infarcted regions with greater fibrotic content show lower mean impedance values and more depressed systolic-diastolic dynamic impedance changes. In conclusion, this study reveals that differences in the degree of yocardial fibrosis can be detected in vivo by local measurement of phasic systolic-diastolic bioimpedance spectrum. Once this new bioimpedance method could be used via a catheter-based device, it would be of potential clinical applicability for the recognition of fibrotic tissue to guide the ablation of atrial or ventricular arrhythmias.Award-winningPostprint (published version

New electrocardiographic criteria to differentiate acute pericarditis and myocardial infarction

Objective Transmural myocardial ischemia induces changes in QRS complex and QT interval duration but, theoretically, these changes might not occur in acute pericarditis provided that the injury is not transmural. This study aims to assess whether QRS and QT duration permit distinguishing acute pericarditis and acute transmural myocardial ischemia. Methods Clinical records and 12-lead electrocardiogram (ECG) at ×2 magnification were analyzed in 79 patients with acute pericarditis and in 71 with acute ST-segment elevation myocardial infarction (STEMI). Results ECG leads with maximal ST-segment elevation showed longer QRS complex and shorter QT interval than leads with isoelectric ST segment in patients with STEMI (QRS: 85.9 ± 13.6 ms vs 81.3 ± 10.4 ms, P = .01; QT: 364.4 ± 38.6 vs 370.9 ± 37.0 ms, P = .04), but not in patients with pericarditis (QRS: 81.5 ± 12.5 ms vs 81.0 ± 7.9 ms, P = .69; QT: 347.9 ± 32.4 vs 347.3 ± 35.1 ms, P = .83). QT interval dispersion among the 12-ECG leads was greater in STEMI than in patients with pericarditis (69.8 ± 20.8 ms vs 50.6 ± 20.2 ms, P <.001). The diagnostic yield of classical ECG criteria (PR deviation and J point level in lead aVR and the number of leads with ST-segment elevation, ST-segment depression, and PR-segment depression) increased significantly (P = .012) when the QRS and QT changes were added to the diagnostic algorithm. Conclusions Patients with acute STEMI, but not those with acute pericarditis, show prolongation of QRS complex and shortening of QT interval in ECG leads with ST-segment elevation. These new findings may improve the differential diagnostic yield of the classical ECG criteria

Seguimiento de la adquisición de competencias profesionales en el Grado de Psicología

El presente trabajo pretende comprobar qué nivel de competencia perciben haber alcanzado los estudiantes del Grado de Psicología en aquellas actividades directamente relacionadas con las tareas de su desempeño profesional. La muestra la constituyen alumnos de varios cursos de Psicología de la Universidad de Salamanca. Los estudiantes responderán on-line, al final de curso, a un cuestionario de autopercepción de competencias profesionales (1=Nada competente; 5=Muy competente) correspondientes a los cuatro perfiles del psicólogo/a - sanitario, educativo, sociocomunitario y laboral-organizativo -. (Castro, 2004). El perfil base de autopercepción de competencias se deriva de las respuestas ofrecidas por los alumnos de 1º curso (N=172) en el primer cuatrimestre. En esta primera fase, los resultados obtenidos muestran que, de las 57 competencias valoradas, los estudiantes se autoperciben como "nada competentes" en la mayoría de ellas (Nivel 1); y solamente como "moderadamente competentes" (Nivel 3) en tres competencias transversales (manejo de informática, de paquetes estadísticos y de inglés). Estos resultados servirán de referencia para posteriores análisis estadísticos comparativos entre cursos. Se espera que los estudiantes autoperciban mayor competencia profesional a medida que se incrementa su formación académica, pudiendo existir diferencias en función de las competencias profesionales asignadas a los distintos perfiles profesionales del psicólogo/a

Electrophysiological effects of selective atrial coronary artery occlusion in humans

Background-The arrhythmogenesis of ventricular myocardial ischemia has been extensively studied, but models of atrial ischemia in humans are lacking. This study aimed at describing the electrophysiological alterations induced by acute atrial ischemia secondary to atrial coronary branch occlusion during elective coronary angioplasty.; Methods and Results-Clinical data, 12-lead ECG, 12-hour Holter recordings, coronary angiography, and serial plasma levels of high-sensitivity troponin T and midregional proatrial natriuretic peptide were prospectively analyzed in 109 patients undergoing elective angioplasty of right or circumflex coronary arteries. Atrial coronary branches were identified and after the procedure patients were allocated into two groups: atrial branch occlusion (ABO, n= 17) and atrial branch patency (non-ABO, n= 92). In comparison with the non-ABO, patients with ABO showed: (1) higher incidence of periprocedural myocardial infarction (20% versus 53%, P= 0.01); (2) more frequent intra-atrial conduction delay (19% versus 46%, P= 0.03); (3) more marked PR segment deviation in the Holter recordings; and (4) higher incidence of atrial tachycardia (15% versus 41%, P= 0.02) and atrial fibrillation (0% versus 12%, P= 0.03). After adjustment by a propensity score, ABO was an independent predictor of periprocedural infarction (odds ratio, 3.4; 95% confidence interval, 1.01-11.6, P< 0.05) and atrial arrhythmias (odds ratio, 5.1; 95% confidence interval, 1.2-20.5, P= 0.02).; Conclusions-Selective atrial coronary artery occlusion during elective percutaneous transluminal coronary angioplasty is associated with myocardial ischemic damage, atrial arrhythmias, and intra-atrial conduction delay. Our data suggest that atrial ischemic episodes might be considered as a potential cause of atrial fibrillation in patients with chronic coronary artery disease.Peer ReviewedPostprint (author's final draft

Incremental prognostic value of lung ultrasound on contemporary heart failure risk scores

Introduction: Over the last decades, several scores have been developed to aid clinicians in assessing prognosis in patients with heart failure (HF) based on clinical data, medications and, ultimately, biomarkers. Lung ultrasound (LUS) has emerged as a promising prognostic tool for patients when assessed at discharge after a HF hospitalization. We hypothesized that contemporary HF risk scores can be improved upon by the inclusion of the number of B-lines detected by LUS at discharge to predict death, urgent visit, or HF readmission at 6- month follow-up. Methods: We evaluated the discrimination improvement of adding the number of B-lines to 4 contemporary HF risk scores (Get with the Guidelines -GWTG-, MAGGIC, Redin-SCORE, and BCN Bio-HF) by comparing the change in the area under the receiver operating curve (AUC), the net reclassification index (NRI), and the integrated discrimination improvement (IDI). The population of the study was constituted by the 123 patients enrolled in the LUS-HF trial, adjusting the analyses by the intervention. Results: The AUC of the GWTG score increased from 0.682 to 0.789 (p = 0.02), resulting in a NRI of 0.608 and an IDI of 0.136 (p < 0.05). Similar results were observed when adding the number of B-lines to the MAGGIC score, with an AUC that increased from 0.705 to 0.787 (p < 0.05). This increase translated into a NRI of 0.608 and an IDI of 0.038 (p < 0.05). Regarding Redin-SCORE at 1-month and 1-year, the AUC increased from 0.714 to 0.773 and from 0.681 to 0.757, although it did not reach statistical significance (p = 0.08 and p = 0.06 respectively). Both IDI and NRI were significantly improved (0.093 and 0.509 in the 1-month score, p < 0.05; 0.056 and 0.111 in the 1-year score, p < 0.05). Lastly, the AUC for the BCN Bio-HF score increased from 0.733 to 0.772, which was statistically non-significant, with a NRI value of 0.363 (p = 0.06) and an IDI of 0.092 (p < 0.05). Conclusion: Adding the results of LUS evaluated at discharge improved the predictive value of most of the contemporary HF risk scores. As it is a simple, fast, and non-invasive test it may be recommended to assess prognosis at discharge in HF patients

Electrophysiological and histological characterization of atrial scarring in a model of isolated atrial myocardial infarction

Background: Characterization of atrial myocardial infarction is hampered by the frequent concurrence of ventricular infarction. Theoretically, atrial infarct scarring could be recognized by multifrequency tissue impedance, like in ventricular infarction, but this remains to be proven. Objective: This study aimed at developing a model of atrial infarction to assess the potential of multifrequency impedance to recognize areas of atrial infarct scar. Methods: Seven anesthetized pigs were submitted to transcatheter occlusion of atrial coronary branches arising from the left coronary circumflex artery. Six weeks later the animals were anesthetized and underwent atrial voltage mapping and multifrequency impedance recordings. The hearts were thereafter extracted for anatomopathological study. Two additional pigs not submitted to atrial branch occlusion were used as controls. Results: Selective occlusion of the atrial branches induced areas of healed infarction in the left atrium in 6 of the 7 cases. Endocardial mapping of the left atrium showed reduced multi-frequency impedance (Phase angle at 307 kHz: from -17.1° ± 5.0° to -8.9° ± 2.6°, p < .01) and low-voltage of bipolar electrograms (.2 ± 0.1 mV vs. 1.9 ± 1.5 mV vs., p < .01) in areas affected by the infarction. Data variability of the impedance phase angle was lower than that of bipolar voltage (coefficient of variability of phase angle at307 kHz vs. bipolar voltage: .30 vs. .77). Histological analysis excluded the presence of ventricular infarction. Conclusion: Selective occlusion of atrial coronary branches permits to set up a model of selective atrial infarction. Atrial multifrequency impedance mapping allowed recognition of atrial infarct scarring with lesser data variability than local bipolar voltage mapping. Our model may have potential applicability on the study of atrial arrhythmia mechanisms.Peer ReviewedPostprint (published version