Pollen-based quantitative reconstructions of Holocene regional vegetation cover (plant-functional types and land-cover types) in Europe suitable for climate modelling.

We present quantitative reconstructions of regional vegetation cover in north-western Europe, western Europe north of the Alps, and eastern Europe for five time windows in the Holocene [around 6k, 3k, 0.5k, 0.2k, and 0.05k calendar years before present (bp)] at a 1° × 1° spatial scale with the objective of producing vegetation descriptions suitable for climate modelling. The REVEALS model was applied on 636 pollen records from lakes and bogs to reconstruct the past cover of 25 plant taxa grouped into 10 plant-functional types and three land-cover types [evergreen trees, summer-green (deciduous) trees, and open land]. The model corrects for some of the biases in pollen percentages by using pollen productivity estimates and fall speeds of pollen, and by applying simple but robust models of pollen dispersal and deposition. The emerging patterns of tree migration and deforestation between 6k bp and modern time in the REVEALS estimates agree with our general understanding of the vegetation history of Europe based on pollen percentages. However, the degree of anthropogenic deforestation (i.e. cover of cultivated and grazing land) at 3k, 0.5k, and 0.2k bp is significantly higher than deduced from pollen percentages. This is also the case at 6k in some parts of Europe, in particular Britain and Ireland. Furthermore, the relationship between summer-green and evergreen trees, and between individual tree taxa, differs significantly when expressed as pollen percentages or as REVEALS estimates of tree cover. For instance, when Pinus is dominant over Picea as pollen percentages, Picea is dominant over Pinus as REVEALS estimates. These differences play a major role in the reconstruction of European landscapes and for the study of land cover-climate interactions, biodiversity and human resources.

Impact of forest disturbance on the pollen influx in lake sediments during the last century.

The pollen accumulation rates of four lakes in different regions of Estonia were estimated in order to study the relationship between pollen influx and the character and intensity of disturbances in the pollen catchment area. The pollen influx data obtained are in accordance with model calculations on the size of the pollen source areas. The influx of arboreal pollen and that of the dominant taxa (mainly Pinus) in the lakes investigated shows that, in the case of small lakes (area 3-6ha) in a forested landscapes, the bulk of the pollen originates from an area within 100-200m around the lake. The distribution patterns of influx from two lakes situated close to each other but at different distances from forest fires show that past disturbances can be reliably detected when the disturbance occurred in the immediate vicinity of the lake and at least 25% of the local pollen source area was involved. In the case of a large lake (137ha) only fires embracing thousands of hectares can be detected in the pollen diagrams.

1994 Architectural Design awards. Windemere Nursing & Rehabilitation Center, Martha's Vineyard; Harold & Patricia Toppel Center for Life Enhancement, Miami; Westminster Place, Oakmont, Pa.

At the 11th annual Architectural Design Awards, sponsored by Contemporary Long Term Care, the following projects were singled out for their innovative designs: New nursing home with 130 beds or less: Windemere Nursing and Rehabilitation Center on Martha's Vineyard. New nursing home with more than 130 units: Harold & Patricia Toppel Center for Life Enhancement, Miami, Fla. Renovated retirement center with 150 beds or less: Westminster Place, Oakmont, Pa. No awards were given in one nursing-home and three retirement-center categories. The competition was held on March 20 in the offices of Backen Arrigoni & Ross of San Francisco. Following is an overview of the competition and a narrative on each of the three entries honored for notable innovations in design.

Prostaglandin release in multiple sclerosis: correlation with disease activity.

Release of prostaglandin E (PGE) was examined in leukocyte cultures from patients with definite MS who had had at least one recent exacerbation, others with chronic progressive or stable MS, and healthy controls. MS patients had higher baseline levels of PGE than did controls. Patients with active symptoms exhibited a sharp increase in PGE release early in or just before the onset of clinical symptoms. Levels dropped early in exacerbation immediately after the burst in PGE synthesis activity. Values gradually increased to control levels and then to preexacerbation levels. Similar rises and falls were not seen in stable MS. MS patients may have a circulating population of activated leukocytes that produce PGE.

Adherence of human peripheral blood lymphocytes to virus infected cells: role of the cytoskeleton and prostaglandin E.

Human peripheral blood lymphocytes from patients with multiple sclerosis (MS) form significantly greater numbers of rosettes with virus infected cells than healthy controls. Because increased lymphocyte adherence in MS may be important to the disease process, we have investigated the mechanisms governing lymphocyte adherence in healthy control volunteers. We have previously shown that prostaglandins E1, E2 (PGE2), and dibutyryl cyclic AMP (db cAMP) increase control lymphocyte adherence to MS levels. We now report that colchicine (10(-7) M) and nocodazole (10(-7) M) significantly increased control lymphocyte adherence to measles virus infected human epithelial (HEp-2) cells. Lumicolchicine had no effect. Cytochalasins A, B, C, and D also had no effect on lymphocyte adherence. Colchicine (10(-5) + 10(-7) M) treatment of mononuclear cells enhanced PGE synthesis in tissue culture. Cytochalasins had no effect on PGE synthesis. Thus, microtubules appear important to adherence of lymphocytes to virus infected cells perhaps by virtue of their involvement and/or control of PG biosynthesis.

Social rehearsal for death and dying.

Dr. Koff, an articulate spokesman of the care system in nursing homes, answers an oft repeated question: "What are sensible and sensitive steps to be dealt with on the subject of death and dying in the institutional setting?" He argues for a "system"in the home which transcends a piecemeal approach to policy making on an important event--death--for the nursing home resident.