For many, the terms aging, maturation and senescence are synonymous and used interchangeably, but they should not be. Whereas senescence represents an endogenously controlled degenerative programme leading to plant or organ death, genetiC aging encompasses a wide array of passive degenerative genetiC processes driven primarily by exogenous factors (Leopold, 1975). Aging is therefore considered a consequence of genetiC lesions that accumulate over time, but by themselves do not necessarily cause death. These lesions are probably made more severe by the increase in size and complexity in trees and their attendant physiology. Thus while the withering of flower petals following pollination can be considered senescence, the loss of viability of stored seeds more clearly represents aging (Norden, 1988). The very recent book "Senescence and Aging in Plants" does not discuss trees, the most dominant group of plants on the earth. Yet both angiospermic and gymnospermic trees also undergo the above phenomena but less is known about them. Do woody plants senesce or do they just age? What is phase change? Is this synonymous with maturation? While it is now becoming recognized that there is no programmed senescence in trees, senescence of their parts, even in gymnosperms (e. g. , needles of temperate conifers las t an average of 3. 5 years), is common; but aging is a readily acknowledged phenomenon. In theory, at least, in the absence of any programmed senescence trees should -live forever, but in practice they do not.

This vivid exposé of corruption and political tyranny in the Dominican Republic rang so true to the reality that the President of that country went on television to denounce the book. Sención's novel follows the lives of three seminary students who suffer from church-state oppression. The book also gives a chilling portrait of Dr. Ramos, a sinister autocrat, who manages to survive six terms as president of his country through manipulation and tyranny.

This volume approaches the history of water in the Iberian Peninsula in a novel way, by linking it to the ongoing international debate on water crisis and solutions to overcome the lack of water in the Mediterranean. What water devices were found? What were the models for these devices? How were they distributed in the villas and monastic enclosures? What impact did hydraulic theoretical knowledge have on these water systems, and how could these systems impact on hydraulic technology? Guided by these questions, this book covers the history of water in the most significant cities, the role of water in landscape transformation, the irrigation systems and water devices in gardens and villas, and, lastly, the theoretical and educational background on water management and hydraulics in the Iberian Peninsula between the sixteenth and the nineteenth centuries. Historiography on water management in the territory that is today Spain has highlighted the region’s role as a mediator between the Islamic masters of water and the Christian world. The history of water in Portugal is less known, and it has been taken for granted that is similar to its neighbour. This book compares two countries that have the same historical roots and, therefore, many similar stories, but at the same time, offers insights into particular aspects of each country. It is recommended for scholars and researchers interested in any field of history of the early modern period and of the nineteenth century, as well as general readers interested in studies on the Iberian Peninsula, since it was the role model for many settlements in South America, Asia and Africa.

This book was originated from a series of lectures given in a course on the physical properties of biological membranes and their functional implica tions. The course was intended to allow students to get acquainted with the physical techniques used to study biological membranes. The experience was valuable and we feel that a detailed description of the procedures used and of various examples of the results obtained allowed many students to become familiar with a theme that is not often part of regular courses on membrane physiology or biophysics. This book is designed as a tutorial guide for graduate students interested in understanding how physical methods can be utilized to study the proper ties of biological membranes. It includes first a detailed description of applications of physical techniques-such as X-ray fiber diffraction methods (Chapter 1), 2H and 13C NMR spectroscopy (Chapter 2), and calorimetry (Chapter 3)-in the study of the properties of lipid model membranes. A description of how to measure molecular mobility in membranes (Chapter 4) follows, and the book concludes with three chapters in which biological membranes are the subject of study. Chapter 5 deals with the acetylcholine receptor and its membrane environment; Chapter 6 discusses how fluorescence techniques can be applied in the study of the calcium ATPase of sarcoplasmic reticulum; and Chapter 7 explains how protein lipid interactions modulate the function of the sodium and proton pumps.