A Structurally Based Analytic Model of Growth and Biomass Dynamics in Single Species Stands of Conifers

A theoretically based analytic model of plant growth in single species conifer communities based on the species fully occupying a site and fully using the site resources is introduced. Model derivations result in a single equation simultaneously describes changes over both, different site conditions (or resources available), and over time for each variable for each species. Leaf area or biomass, or a related plant community measurement, such as site class, can be used as an indicator of available site resources. Relationships over time (years) are determined by the interaction between a stable foliage biomass in balance with site resources, and by the increase in the total heterotrophic biomass of the stand with increasing tree size. This structurally based, analytic model describes the relationships between plant growth and each species’ functional depth for foliage, its mature crown size, and stand dynamics, including the self‐thinning. Stand table data for seven conifer species are used for verification of the model. Results closely duplicate those data for each variable and species. Assumptions used provide a basis for interpreting variations within and between the species. Better understanding of the relationships between the MacArthur consumer resource model, the Chapman–Richards growth functions, the metabolic theory of ecology, and stand development resulted

Efficiency and Effectiveness of Social Spending

In this qualitative sociological and quantitative economic policy paper, we start out from the assumption of a very recent European Commission Background paper on the “Efficiency and effectiveness of social spending”, which says the effectiveness of social spending can be defined by the degree to which the realized allocation approaches the socially desired outcome. The conclusions listed in the Commission paper are found far reaching and not supported by the empirical data. We perform such an analysis, starting from advances in recent literature. A more encompassing sociological perspective on the issue and factor analytical calculations is presented, which supports our general argument about the efficiency of the Scandinavian model. The social quality approach provides an alternative perspective on welfare system analysis, focusing on public policies rather than social policies. The empirical evidence, suggests that in terms of the efficiency of the European social model, the geography of comparative performance include: the direct action against social exclusion, health and family social expenditures, the neo-liberal approach, and the unemployment benefit centred approach. Applying rigorous comparative social science methodology, we also arrive at the conclusion that in terms of the initial ECOFIN definition of efficiency, the data presented in this article suggest that apart from Finland and the Netherlands, three new EU-27 member countries, especially the Czech Republic and Slovenia, provide interesting answers to the question about the efficiency of state expenditures in reducing poverty rates.social spending, European Commission, index numbers and aggregation, cross-sectional models, spatial models, economic integration, regional economic activity, international factor movements, nternational political economy

Genetic aspects of the biodiversity of rangeland plants

Biodiversity is the variety of life and its processes. Diversity cannot be described unless the differences between organisms can be detected and measured. The concept of genetic diversity is usually confined to individual organisms, populations, and species and may be considered as heritable differences among taxa capable of gene exchange. New macromolecular methods together with traditional morphological, cytogenetic, hybridization, and breeding-system analytical methods are providing greater detail that allows a finer resolution of genetic diversity. Rangeland plant biodiversity studies of shrub, forb, grass, and tree taxa are demonstrating genetic diversity data available from rangelands and, in general, rangeland plant genetic diversity studies are in the beginning stages. The influences of past climatic changes on plant genetic diversity studies are in the beginning stages. The influences of past climatic changes on plant genetic diversity are also only just beginning to be understood. Both conservation and use of rangeland plant resources have genetic bases. Genetic diversity studies are important for discovering and documenting the sources and patterns of variation. That information is vital if genetic diversity is to be protected and preserved so that rangeland plant resources can be effectively used and sustained to maintain future options

The Economics of Fuel Management: Wildfire, Invasive Plants, and the Dynamics of Sagebrush Rangelands in the Western United States

In this article we develop a simulation model to evaluate the economic efficiency of fuel treatments and apply it to two sagebrush ecosystems in the Great Basin of the western United States: the Wyoming Sagebrush Steppe and Mountain Big Sagebrush ecosystems. These ecosystems face the two most prominent concerns in sagebrush ecosystems relative to wildfire: annual grass invasion and native conifer expansion. Our model simulates long-run wildfire suppression costs with and without fuel treatments explicitly incorporating ecological dynamics, stochastic wildfire, uncertain fuel treatment success, and ecological thresholds. Our results indicate that, on the basis of wildfire suppression costs savings, fuel treatment is economically efficient only when the two ecosystems are in relatively good ecological health. We also investigate how shorter wildfire-return intervals, improved treatment success rates, and uncertainty about the location of thresholds between ecological states influence the economic efficiency of fuel treatments

Long‐Term Effects of Tree Expansion and Reduction on Soil Climate in a Semiarid Ecosystem

In sagebrush ecosystems, pinyon and juniper tree expansion reduces water available to perennial shrubs and herbs. We measured soil water matric potential and temperatures at 13–30 and 50–65 cm soil depths in untreated and treated plots across a range of environmental conditions. We sought to determine the effects of tree expansion, tree reduction treatments, and expansion phase at time of treatment over 12–13 yr post‐treatment. Because the effects of tree reduction on vegetation can vary with the soil temperature/moisture regime, we also analyzed differences in soil climate variables between the mesic/aridic‐xeric and frigid/xeric regime classifications for our sites. Growing conditions during all seasons except spring were greatly limited by lack of available water, low temperatures, or both. Advanced tree expansion reduced wet days (total hours per 24 hr when hourly average soil water matric potential \u3e−1.5 MPa), especially in early spring. Fire and mechanical tree reduction increased wet days and wet degree days (sum of hourly soil temperatures \u3e0°C when soil is wet per 24 hr) compared with no treatment for most seasons. Burning resulted in higher soil temperatures than untreated or mechanically treated woodlands. Tree reduction at advanced expansion phases increased wet days in spring more than when implemented at earlier phases of expansion. Added wet days from tree reduction were negatively associated with October through June precipitation and vegetation cover, rather than time since treatment, with more wet days added on drier sites and years. The longer period of water availability in spring supports increased growth and cover of not only shrubs and perennial herbs, but also invasive weeds on warmer and drier sites, for many years after tree reduction. We found that sites classified as mesic/aridic‐xeric had warmer soil temperatures all seasons and were drier in spring and winter than sites classified as frigid/xeric. Land managers should consider reducing trees at earlier phases of expansion or consider revegetation when treating at advanced phases on these warmer and drier sites that lack perennial herb potential

Response of Conifer-Encroached Shrublands in the Great Basin to Prescribed Fire and Mechanical Treatments

In response to the recent expansion of piñon and juniper woodlands into sagebrush-steppe communities in the northern Great Basin region, numerous conifer-removal projects have been implemented, primarily to release understory vegetation at sites having a wide range of environmental conditions. Responses to these treatments have varied from successful restoration of native plant communities to complete conversion to nonnative invasive species. To evaluate the general response of understory vegetation to tree canopy removal in conifer-encroached shrublands, we set up a region-wide study that measured treatment-induced changes in understory cover and density. Eleven study sites located across four states in the Great Basin were established as statistical replicate blocks, each containing fire, mechanical, and control treatments. Different cover groups were measured prior to and during the first 3 yr following treatment. There was a general pattern of response across the wide range of site conditions. There was an immediate increase in bare ground and decrease in tall perennial grasses following the fire treatment, but both recovered by the second or third growing season after treatment. Tall perennial grass cover increased in the mechanical treatment in the second and third year, and in the fire treatment cover was higher than the control by year 3. Nonnative grass and forb cover did not increase in the fire and mechanical treatments in the first year but increased in the second and third years. Perennial forb cover increased in both the fire and mechanical treatments. The recovery of herbaceous cover groups was from increased growth of residual vegetation, not density. Sagebrush declined in the fire treatment, but seedling density increased in both treatments. Biological soil crust declined in the fire treatment, with no indications of recovery. Differences in plant response that occurred between mechanical and fire treatments should be considered when selecting management options

Developing a Model Framework for Predicting Effects of Woody Expansion and Fire on Ecosystem Carbon and Nitrogen in a Pinyon-Juniper Woodland

Sagebrush-steppe ecosystems are one of the most threatened ecosystems in North America due to woodland expansion, wildfire, and exotic annual grass invasion. Some scientists and policy makers have suggested that woodland expansion will lead to increased carbon (C) storage on the landscape. To assess this potential we used data collected from a Joint Fire Sciences Program demonstration area to develop a Microsoft Excel™ based biomass, carbon, and nitrogen (N) spreadsheet model. The model uses input for tree cover, soil chemistry, soil physical properties, and vegetation chemistry to estimate biomass, carbon, and nitrogen accumulation on the landscape with woodland expansion. The model also estimates C and N losses associated with prescribed burning. On our study plots we estimate in treeless sagebrush-steppe ecosystems, biomass accounts for 4.5 Mg ha−1 C and 0.3 Mg ha−1 N this is \u3c10% of total estimated ecosystem C and N to a soil depth of 53 cm, but as tree cover increases to near closed canopy conditions aboveground biomass may account for 62 Mg ha−1 C and 0.6 Mg ha−1 N which is nearly 53% of total estimated ecosystem C and 13% of total estimated ecosystem N to a soil depth of 53 cm. Prescribed burning removes aboveground biomass, C and N, but may increase soil C at areal tree cover below 26%. The model serves as a tool by which we are able to assess our understanding of the system and identify knowledge gaps which exist for this ecosystem. We believe that further work is necessary to quantify herbaceous biomass, root biomass, woody debris decomposition, and soil C and N with woodland expansion and prescribed fire. It will also be necessary to appropriately scale these estimates from the plot to the landscape

Clinical Imaging of the Heterogeneous Group of Triple-negative Breast Cancer

BACKGROUND/AIM Triple-negative breast cancer (TNBC) can be divided into subtypes of basal-like (BL), mesenchymal-like (ML), luminal androgen receptor (LAR), and immunomodulatory (IM). The aim of our study was to assess whether there are distinct radiologic features within the different TNBC subtypes and whether this has potential clinical impact. PATIENTS AND METHODS Imaging pictures of 135 patients with TNBC were re-evaluated. TNBC subtyping was performed on asservated tumor tissue using a panel of antibodies. RESULTS Mammographic margins of LAR-TNBC were more often spiculated (24.3% versus 0-4.1%). BL-TNBC presented more frequent a mass without calcification in mammogram than other subtypes (71.4% versus 48.6-57.9%). In ultrasound, ML and LAR were described more often with smooth borders. CONCLUSION The histopathological subtype of TNBC influences its presentation in ultrasound and mammogram. This can reflect a different growth pattern of the subtypes and may have an impact on the early diagnosis of TNBC