Heartbeat-to-heartbeat cardiac tissue characterization

Current clinical MRI techniques are able to detect several cardiac tissue alterations, but such detections are often only possible after irreversible remodeling of the heart has occurred. Since a compromised tissue oxygenation balance is expected to play an early role in most cardiovascular diseases, a novel cardiac MRI technique is developed. This technique was initially translated from the brain and is widely known under the name “blood oxygenation level dependent” (BOLD) imaging. With the recent improvements and advances of the MRI systems, the translation of this technique to the heart is finally possible by acquiring BOLD sensitive maps during every heartbeart. This heartbeat-to-heartbeat BOLD imaging technique enables the detection of a change in BOLD in the heart over the time of a breath-hold. Moreover, this BOLD change is compromised and even reversed in hypertensive patients, which indicates a reduced responsiveness of the cardiac vasculature in this patient population. These first results confirm the potential of this cardiac BOLD imaging technique to contribute in understanding the role of microvascular diseases in cardiovascular risk populations, including people with obesity and diabetes. Furthermore, several other improvements are being investigated, such as; increasing the coverage to enable imaging of the whole heart in a single breath-hold and using a contrast medium to extract more information about the vasculature. However, even without these improvements this cardiac BOLD MRI technique can already be highly beneficial to detect cardiac blood oxygenation changes as an early marker for cardiovascular diseases, which was not possible until now

The faces of death: regional differentiation in cause-specific mortality in the past

In mortality research, much attention has been paid to the strong geographical differentials in mortality levels and in modern mortality decline, as the analysis of this geographical differentiation might hold the key to explaining the determinants of mortality change. The use of historical cause-specific mortality data has proved a challenging, although very insightful, means to this end. The four contributions to this Special Issue focus on cause-specific mortality in the past, both to reassess older data using new insights and to challenge existing insights by using new data and methods. These papers, of which earlier versions were presented during the 38th SSHA Meeting in Chicago, 21-24 November, 2013, explore mortality at different stages of the life course, ranging from early infancy to old age. Moreover, each paper revolves around a different group of causes of death. Although the papers are in many ways rather different, together they demonstrate how different data, theoretical frameworks and methodologies can push the boundaries of research into the trends and determinants of historical mortality patterns.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication of the final version

Situación y tendencias demográficas recientes en Centroamérica

Incluye Bibliografí

Keep Your Eyes on Development: The Behavioral and Neurophysiological Development of Visual Mechanisms Underlying Form Processing

Visual form perception is essential for correct interpretation of, and interaction with, our environment. Form perception depends on visual acuity and processing of specific form characteristics, such as luminance contrast, spatial frequency, color, orientation, depth, and even motion information. As other cognitive processes, form perception matures with age. This paper aims at providing a concise overview of our current understanding of the typical development, from birth to adulthood, of form-characteristic processing, as measured both behaviorally and neurophysiologically. Two main conclusions can be drawn. First, the current literature conveys that for most reviewed characteristics a developmental pattern is apparent. These trajectories are discussed in relation to the organization of the visual system. The second conclusion is that significant gaps in the literature exist for several age-ranges. To complete our understanding of the typical and, by consequence, atypical development of visual mechanisms underlying form processing, future research should uncover these missing segments

The age bias in labeling facial expressions in children: Effects of intensity and expression

Emotion reasoning, including labeling of facial expressions, is an important building block for a child's social development. This study investigated age biases in labeling facial expressions in children and adults, focusing on the influence of intensity and expression on age bias. Children (5 to 14 years old; N = 152) and adults (19 to 25 years old; N = 30) labeled happiness, disgust or sadness at five intensity levels (0%; 25%; 50%; 75%; and 100%) in facial images of children and adults. Sensitivity was computed for each of the expression-intensity combinations, separately for the child and adult faces. Results show that children and adults have an age bias at low levels of intensity (25%). In the case of sadness, children have an age bias for all intensities. Thus, the impact of the age of the face seems largest for expressions which might be most difficult to recognise. Moreover, both adults and children label most expressions best in adult rather than child faces, leading to an other-age bias in children and an own-age bias in adults. Overall, these findings reveal that both children and adults exhibit an age bias in labeling subtle facial expressions of emotions