Guide to the Weber Vineyards Collection

The Weber Collection holds information of harvest details of the Weber Vineyards from 1984-1995. Along with a few pictures, this collection retains documents on spray programs, harvesting records, research, and finances. There is also information on day-to-day schedules of the vineyard, to-do lists, and daily notes

Sampling with probabilities proportional to the variable of interest

To estimate the mean sojourn time, a sample of Tilburg fair visitors was asked for the duration of their stay on the fair grounds. The longer a visitor's sojourn, the larger his/her probability of being interviewed will be; therefore, longer sojourn times will be overrepresented in the sample. As a consequence, the arithmetic sample mean is not a suitable estimator. The paper places this problem against a theoretical background. As a better estimator the harmonic mean of the observed sojourn times is presented. In addition, a variance estimator is given. The properties of these estimators are difficult to derive analytically. Instead, their behaviour is studied in a number of examples.Probability;Estimation;Sampling;statistics

The spatial dimension of social capital

Social capital pertains to the social relations between humans, and since these social relations have a spatial dimension, so too does social capital. However, the spatial dimension of social capital has received little attention in the literature so far. Even in a globalizing world where electronic and virtual communication have the potential to defeat the need for geographical proximity, it is still relevant to consider the spatial dimension of social capital. After all, human beings exist most prominently in real rather than in virtual space. This special issue undertakes an inquiry into the spatial dimension of social capital from an explorative perspective. It aims to further theoretical and empirical understanding of the spatial dimension of social capital. As editors we recognize that the debate on social capital is still ongoing in the literature and that it is fed from different, sometimes conflicting perspectives. Therefore, the spatial dimension of social capital can only be conceptualized in the light of these different perspectives, which necessitates an explorative approach. Nonetheless, the various contributions of this special issue allow several conclusions that are valuable to the ongoing discussion on social capital and its spatial dimension. In the first part of this introductory paper, we discuss social capital from a conceptual angle, as we distinguish between two key approaches (the “structuralist” and “interactionist” approaches). We then argue how these approaches may be helpful to the understanding of the spatial dimension of social capital. In the second part, we introduce the various contributions and explain how they contribute to the aim of this special issue.Social capital; Spatial social capital; Spatial social networks

Structure of the ATP-Synthase from Chloroplasts and Mitochondria Studied by Electron Microscopy

The structure of the ATP-synthase, F0F1 , from spinach chloroplasts and beef heart mitochondria has been investigated by electron microscopy with negatively stained specimens. The detergent-solubilized ATP-synthase forms string-like structures in which the F0 parts are aggregated. In most cases, the F, parts are arranged at alternating sides along the string. The F0 part has an approximate cylindrical shape with heights of 8.3 and 8.9 nm and diameters of 6.2 and 6.4 nm for the chloroplast and mitochondrial enzyme, respectively. The F, parts are disk-like structures with a diameter of about 11.5 nm and a height of about 8.5 nm. The F, parts are attached to the strings, composed of Fn parts, in most cases, with their smallest dimension parallel to the strings. The stalk connecting F0 and F, has a length of 3.7 nm and 4.3 nm and a diameter of 2.7 nm and 4.3 nm for the chloroplast and mitochondrial enzyme, respectively

Plants lacking the main light-harvesting complex retain photosystem II macro-organization

Photosystem II (PSII) is a key component of photosynthesis, the process of converting sunlight into the chemical energy of life. In plant cells, it forms a unique oligomeric macrostructure in membranes of the chloroplasts. Several light-harvesting antenna complexes are organized precisely in the PSII macrostructure—the major trimeric complexes (LHCII) that bind 70% of PSII chlorophyll and three minor monomeric complexes—which together form PSII supercomplexes. The antenna complexes are essential for collecting sunlight and regulating photosynthesis, but the relationship between these functions and their molecular architecture is unresolved. Here we report that antisense Arabidopsis plants lacking the proteins that form LHCII trimers have PSII supercomplexes with almost identical abundance and structure to those found in wild-type plants. The place of LHCII is taken by a normally minor and monomeric complex, CP26, which is synthesized in large amounts and organized into trimers. Trimerization is clearly not a specific attribute of LHCII. Our results highlight the importance of the PSII macrostructure: in the absence of one of its main components, another protein is recruited to allow it to assemble and function