Large-scale synchrony of gap dynamics and the distribution of understory tree species in maple-beech forests

Large-scale synchronous variations in community dynamics are well documented for a vast array of organisms, but are considerably less understood for forest trees. Because of temporal variations in canopy gap dynamics, forest communities—even old-growth ones—are never at equilibrium at the stand scale. This paucity of equilibrium may also be true at the regional scale. Our objectives were to determine (1) if nonequilibrium dynamics caused by temporal variations in the formation of canopy gaps are regionally synchronized, and (2) if spatiotemporal variations in canopy gap formation aVect the relative abundance of tree species in the understory. We examined these questions by analyzing variations in the suppression and release history of Acer saccharum Marsh. and Fagus grandifolia Ehrh. from 481 growth series of understory saplings taken from 34 mature stands. We observed that (1) the proportion of stems in release as a function of time exhibited a U-shaped pattern over the last 35 years, with the lowest levels occurring during 1975–1985, and that (2) the response to this in terms of species composition was that A. saccharum became more abundant at sites that had the highest proportion of stems in release during 1975–1985. We concluded that the understory dynamics, typically thought of as a stand-scale process, may be regionally synchronized

Use of a spatially explicit individual-tree model (SORTIE/BC) to explore the implications of patchiness in structurally complex forests

The discipline of silviculture is evolving rapidly, moving from an agricultural model that emphasized simple stand structures toward a natural disturbance- or ecosystem-based model where stands are managed for multiple species and complex structures. Predicting stand dynamics and future yields in mixed-species complex structured stands cannot be easily accomplished with traditional field experiments. We outline the development and structure of SORTIE/BC, a descendent of the SORTIE model. SORTIE/BC is a light-mediated, spatially explicit, mixed-species forest model that makes population dynamic forecasts for juvenile and adult trees. We use the model to simulate partial cutting prescriptions in temperate deciduous, boreal and temperate coniferous mixed-species forests. The species, amount and spatial pattern of canopy tree removal had a major influence on understory light environments. Low and uniform removal of canopy trees were less successful in favouring the growth and survival of regenerating trees of intermediate to shade intolerant species and the growth of retained canopy trees than patch removal. In the boreal mixedwood, strip-cutting can maintain mixed stands but careful attention must be paid to buffer and strip management to optimize stand growth. We conclude that SORTIE/ BC can be very useful to explore and explain the silvicultural implications of complex silvicultural prescriptions for which there are no existing long-term experiments. © 2003 Elsevier B.V. All rights reserved

PCN74 Cost-Effectiveness of Radium-223 Dichloride (Radium-223) In Alsympca: A Cost-Effectiveness Analysis of Radium-223+Best Standard of Care (Bsoc) Compared With Placebo+Bsoc In Treatment of Castration-Resistant Prostate Cancer (Crpc) And Symptomatic Bone Metastases In Canada

Current models of sexual functioning imply an important role for both automatic and controlled appraisals. Accordingly, it can be hypothesized that erectile dysfunction may be due to the automatic activation of negative appraisals at the prospect of sexual intercourse. However, previous research showed that men with sexual dysfunction exhibited relatively strong automatic sex-positive instead of sex-negative associations. This study tested the robustness of this unexpected finding and, additionally, examined the hypothesis that perhaps more specific sex-failure versus sex-success associations are relevant in explaining sexual dysfunction and distress. Male urological patients (N = 70), varying in level of sexual functioning and distress, performed two Single-Target Implicit Association Tests (ST-IATs) to assess automatic associations of visual erotic stimuli with attributes representing affective valence (“liking”; positive versus negative) and sexual success versus sexual failure. Consistent with the earlier findings, the lower the scores on sexual functioning, the stronger the automatic sex-positive associations. This association was independent of explicit associations and most prominent in the younger age group. Automatic sex-positive and sex-failure associations showed independent relationships with sexual distress. The relationship between sexual distress and sex-failure associations is consistent with the view that automatic associations with failure may contribute to sexual distress

P-Selectin or Intercellular Adhesion Molecule (Icam)-1 Deficiency Substantially Protects against Atherosclerosis in Apolipoprotein E–Deficient Mice

The expression of leukocyte and endothelial cell adhesion molecules (CAMs) is essential for the emigration of leukocytes during an inflammatory response. The importance of the inflammatory response in the development of atherosclerosis is indicated by the increased expression of adhesion molecules, proinflammatory cytokines, and growth factors in lesions and lesion-prone areas and by protection in mice deficient in various aspects of the inflammatory response. We have quantitated the effect of deficiency for intercellular adhesion molecule (ICAM)-1, P-selectin, or E-selectin on atherosclerotic lesion formation at 20 wk of age in apolipoprotein (apo) E−/− (deficient) mice fed a normal chow diet. All mice were apo E−/− and CAM+/+ or CAM−/− littermates, and no differences were found in body weight or cholesterol levels among the various genotypes during the study. ICAM-1−/− mice had significantly less lesion area than their ICAM-1+/+ littermates: 4.08 ± 0.70 mm2 for −/− males vs. 5.87 ± 0.66 mm2 for +/+ males, and 3.95 ± 0.65 mm2 for −/− females vs. 5.59 ± 1.131 mm2 for +/+ females, combined P < 0.0001. An even greater reduction in lesion area was observed in P-selectin−/− mice: 3.06 ± 1.04 mm2 for −/− males vs. 5.09 ± 1.22 mm2 for +/+ males, and 2.85 ± 1.26 mm2 for −/− females compared with 5.60 ± 1.19 mm2 for +/+ females, combined P < 0.001. The reduction in lesion area for the E-selectin null mice, although less than that seen for ICAM-1 or P-selectin, was still significant (4.54 ± 2.14 mm2 for −/− males vs. 5.92 ± 0.63 mm2 for +/+ males, and 4.38 ± 0.85 mm2 for −/− females compared with 5.94 ± 1.44 mm2 for +/+ females, combined P < 0.01). These results, coupled with the closely controlled genetics of this study, indicate that reductions in the expression of P-selectin, ICAM-1, or E-selectin provide direct protection from atherosclerotic lesion formation in this model

Modelling agronomic properties of Technosols constructed with urban wastes

International audienceThe greening of urban and suburban areas requires large amounts of arable earth that is a non-renewable resource. However, concentration of population in cities leads to the production of high amounts of wastes and by-products that are nowadays partly recycled as a resource and quite systematically exported out of urban areas. To preserve natural soil resources, a strategy of waste recycling as fertile substitutes is proposed. Eleven wastes are selected for their environmental harmlessness and their contrasted physico-chemical properties for their potential use in pedological engineering. The aim is (i) to demonstrate the feasibility of the formulation of fertile substrates exclusively with wastes and (ii) to model their physico-chemical properties following various types, number and proportions of constitutive wastes. Twenty-five binary and ternary combinations are tested at different ratios for total carbon, Olsen available phosphorus, cation exchange capacity, water pH, water retention capacity and bulk density. Dose-response curves describe the variation of physico-chemical properties of mixtures depending on the type and ratio of selected wastes. If these mixtures mainly mimic natural soils, some of them present more extreme urban soil features, especially for pH and P Olsen. The fertility of the new substrates is modelled by multilinear regressions for the main soil properties