Vitronectin at sites of cell-substrate contact in cultures of rat myotubes

Affinity-purified antibodies to the serum glycoprotein, vitronectin, were used to study sites of cell-substrate contact in cultures of rat myotubes and fibroblasts. Cells were removed from the substrate by treatment with saponin, leaving fragments of plasma membrane attached to the glass coverslip. When stained for vitronectin by indirect immunofluorescence, large areas of the substrate were brightly labeled. The focal contacts of fibroblasts and the broad adhesion plaques of myotubes appeared black, however, indicating that the antibodies had failed to react with those areas. Contact sites within the adhesion plaque remained unlabeled after saponin-treated samples were extracted with Triton X-100, or after intact cultures were sheared with a stream of fixative. These procedures expose extracellular macromolecules at the cell-substrate interface, which can then be labeled with concanavalin A. In contrast, when samples were sheared and then sonicated to remove all the cellular material from the coverslip, the entire substrate labeled extensively and almost uniformly with anti- vitronectin. Extracellular molecules associated with substrate contacts were also studied after freeze-fracture, using a technique we term "post-release fracture labeling." Platinum replicas of the external membrane were removed from the glass with hydrofluoric acid to expose the extracellular material. Anti-vitronectin, bound to the replicas and visualized by a second antibody conjugated to colloidal gold, labeled the broad areas of close myotube-substrate attachment and the nearby glass equally well. Our results are consistent with the hypothesis that vitronectin is present at all sites of cell-substrate contact, but that its antigenic sites are obscured by material deposited by both myotube and fibroblast cells

PROJECT FOR THE ANALYSIS OF LAND TENURE AND AGRICULTURAL PRODUCTIVITY IN THE REPUBLIC OF MACEDONIA

The paper arises out of the Land Market Project and covers detailed data at the individual farm level and in-depth analyses of legal and historical processes. The agricultural sector in Macedonia is characterized by two very different farm enterprise types: small family farms operating on privately owned land, and large socially owned farms. About 30 percent of the total arable land in Macedonia belongs to socially owned farms. Most of the balance belong to the private farm sector; the cooperative sector occupies a small percentage of the arable land. The Land Markets Project addressed five tasks during the six-month term of the project: (1) assess the appropriateness of legislation, regulations, and institutions affecting land tenure and land use, (2) document and assess the land-related constraints to increased productivity and profitability of private farms, (3) document and assess the land-related constraints to increased productivity and profitability of socially owned farms, (4) propose land policy adjustments that would promote increased productivity and profitability of the agricultural sector, (5) identify financial and technical assistance to support the development of land markets that promote efficient, sustainable, and equitable increases in agricultural incomes. This paper reports the results of the first three tasks and then presents a comparative review of the land tenure and productivity results for both the private and the social sector. This comparison forms a basis for policy dialogue. The paper also includes a comprehensive discussion of the policy recommendations that stem from the Land Markets Project.Land tenure--Macedonia (Republic), Land use, Rural--Economic aspects--Macedonia (Republic), Farms, Size of--Macedonia (Republic), Agriculture--Economic aspects--Macedonia (Republic), Agricultural productivity--Macedonia (Republic), Land markets--Macedonia (Republic), Agrarian structure--Macedonia (Republic), Land Economics/Use, Productivity Analysis,

On Greenberg's LL-invariant of the symmetric sixth power of an ordinary cusp form

We derive a formula for Greenberg's $L$-invariant of Tate twists of the symmetric sixth power of an ordinary non-CM cuspidal newform of weight $\geq4$, under some technical assumptions. This requires a "sufficiently rich" Galois deformation of the symmetric cube which we obtain from the symmetric cube lift to \GSp(4)_{/\QQ} of Ramakrishnan--Shahidi and the Hida theory of this group developed by Tilouine--Urban. The $L$-invariant is expressed in terms of derivatives of Frobenius eigenvalues varying in the Hida family. Our result suggests that one could compute Greenberg's $L$-invariant of all symmetric powers by using appropriate functorial transfers and Hida theory on higher rank groups.Comment: 20 pages, submitte

Population Dynamics of Oryzomys Palustris and Microtus Pennsylvanicus in Virginia Tidal Marshes

Oryzomys palustris (marsh rice rat) and Microtus pennsylvanicus (meadow vole) cohabit coastal marshes in the mid-Atlantic US. Both were live-trapped for 23 months at two tidal marsh sites in Virginia to assess their demography near the margins of their distributions. In the presence of dense vegetation, population dynamics of the two species were seasonal and positively correlated, with densities declining through the winter. At the more sparsely vegetated site, densities of both species were lower, and densities of M. pennsylvanicus were negatively correlated with those of O. palustris. Patterns of reproduction differed between the species. O. palustris was reproductively most active in summer and least so in winter, whereas female M. pennsylvanicus decreased reproductive activity during summer

Emotion regulation predicts marital satisfaction: more than a wives' tale.

Emotion regulation is generally thought to be a critical ingredient for successful interpersonal relationships. Ironically, few studies have investigated the link between how well spouses regulate emotion and how satisfied they are with their marriages. We utilized data from a 13-year, 3-wave longitudinal study of middle-aged (40-50 years old) and older (60-70 years old) long-term married couples, focusing on the associations between downregulation of negative emotion (measured during discussions of an area of marital conflict at Wave 1) and marital satisfaction (measured at all 3 waves). Downregulation of negative emotion was assessed by determining how quickly spouses reduced signs of negative emotion (in emotional experience, emotional behavior, and physiological arousal) after negative emotion events. Data were analyzed using actor-partner interdependence modeling. Findings showed that (a) greater downregulation of wives' negative experience and behavior predicted greater marital satisfaction for wives and husbands concurrently and (b) greater downregulation of wives' negative behavior predicted increases in wives' marital satisfaction longitudinally. Wives' use of constructive communication (measured between Waves 1 and 2) mediated the longitudinal associations. These results show the benefits of wives' downregulation of negative emotion during conflict for marital satisfaction and point to wives' constructive communication as a mediating pathway