Legacy Effects in Prairie Restoration: A 73-Year Spatial History

Black Earth Rettenmund Prairie State Natural Area, one of the highest quality prairie remnants in southern Wisconsin’s Driftless Area, has been the target of extensive restoration efforts since it was acquired by the Nature Conservancy (TNC) in 1986. In the present work, I analyzed the spatial history of this prairie using a Geographical Information System (GIS) and an extended series of air photos, on-the-ground surveys, early maps, and land-use records. In 1937, when the first air photo was taken, the site was nearly devoid of trees and shrubs. In subsequent years, the site became progressively woody until at the time of purchase by TNC, it was over half covered by shrubs and trees. Maps and field notes made by TNC and the Wisconsin Department of Natural Resources (DNR) provided detailed information on the woody taxa at the time of acquisition. Quaking aspen (Populus tremuloides), eastern cottonwood (P. deltoides), and sumac (Rhus glabra) were the dominant woody species. Stewardship files during more than 25 years of restoration work provided data on the effort expended. Tree and shrub removal and frequent prescribed burns were used to restore the prairie. Although these efforts led to substantial success, a legacy of the woody vegetation remained, complicating restoration efforts. Sumac and gray dogwood (Cornus racemosa) are particularly troublesome, but brambles (Rubus sp.) and grape (Vitis sp.) also present problems. I used a Global Positioning System (GPS) to define boundaries of current woody areas and I found that they corresponded closely to the areas previously dominated by trees and shrubs

Oak Savanna Restoration: A Case Study

A degraded oak savanna in southwestern Wisconsin is being restored using intensive cutting of undesirable shrubs- buckthorn (Rhamnus cathartica), prickly ash (Zanthoxylum americanum), honeysuckle (Lonicera spp.)-and selective removal of trees that are crowding the open-grown bur (Quercus macrocarpa) and white (Q. alba) oaks. Land use records and historic aerial photographs have been used to guide the restoration process. Slippery elm (Ulmus rubra), black walnut (Juglans nigra), black cherry (Prunus serotina), and black oak (Q. velutina) are being removed by cutting and burning or by converting to lumber or firewood. Hundreds of aspen (Populus tremuloides and P. grandentata) have been killed by girdling with subsequent cutting and burning. Management involves controlled burns and extensive weed control. Removal of invasive shrubs and trees has exposed the ground layer to higher light intensities and stimulated the growth of savanna forbs and grasses. A number of typical herbaceous savanna species have reappeared after clearing or have been successfully introduced from local sources. However, control of brambles (Rubus spp.) and regrowth of buckthorn and honeysuckle remain principal problems. One savanna species endangered in Wisconsin-purple milkweed (Asclepias purpurascens)-was first seen in the savanna after a single controlled burn, and appears to be spreading. The redheaded woodpecker (Melanerpes erythrocephalus), a typical savanna bird, was first seen after shrub and canopy clearing in the savanna. Tree removal is a slow and expensive operation, and strategies for preventing damage to the groundlayer during tree removal had to be devised. About 70 acres (28 hectares) of savanna have been restored during nine years

The (After) Life-Cycle Theory of Religious Contributions

We construct and estimate an economic model of religious giving. We employ a dynamic consumer optimization model with mortality in which intra-temporal utility stems from both consumption and religious contributions. Individuals also decide how to allocate resources between religious contributions (which have both a this-life consumption value and an after-life investment value) and other consumption expenditures. If religious contributions do not have an after-life investment value, the ratio of contributions to consumption expenditures should be unrelated to the probability of death. However, if there is an investment value from religious giving, individuals should allocate a greater share of their income to religious contributions as their probability of death increases. We estimate the model using data from the Consumer Expenditure Survey on the consumption and religious contribution patterns of a repeated cross-section of households and of a synthetic cohort panel. We find strong evidence that individuals behave as if religious contributions have a value in the after-life, in a manner consistent with the after life-cycle model. The estimates of the structural parameters of the model also imply that while after-life investment considerations (i.e. impending death) are an important determinant of the life-cycle profile of religious contributions, within-life (i.e. religious consumption) factors pin down a household’s average level of religious contributions over a lifetime.god, life-cycle, consumption, religion, tithing

Characterizing the Hydrology of Shallow Floodplain Lakes in the Slave River Delta, NWT, Canada, Using Water Isotope Tracers

The relative importance of major hydrological processes on thaw season 2003 lakewater balances in the Slave River Delta, NWT, Canada, is characterized using water isotope tracers and total suspended sediment (TSS) analyses. A suite of 41 lakes from three previously recognized biogeographical zones—outer delta, mid-delta, and apex—were sampled immediately following the spring melt, during summer, and in the fall of 2003. Oxygen and hydrogen isotope compositions were evaluated in the context of an isotopic framework calculated from 2003 hydroclimatic data. Our analysis reveals that flooding from the Slave River and Great Slave Lake dominated early spring lakewater balances in outer and most mid-delta lakes, as also indicated by elevated TSS concentrations (\u3e0.01 g L-1). In contrast, the input of snowmelt was strongest on all apex and some mid-delta lakes. After the spring melt, all delta lakes underwent heavy-isotope enrichment due to evaporation, although lakes flooded by the Slave River and Great Slave Lake during the spring freshet continued to be more depleted isotopically than those dominated by snowmelt input. The isotopic signatures of lakes with direct connections to the Slave River or Great Slave Lake varied throughout the season in response to the nature of the connection. Our findings provide the basis for identifying three groups of lakes based on the major factors that control their water balances: (1) flood-dominated (n=10), (2) evaporation-dominated (n=25), and (3) exchange-dominated (n=6) lakes. Differentiation of the hydrological processes that influence Slave River Delta lakewater balances is essential for ongoing hydroecological and paleohydrological studies, and ultimately, for teasing apart the relative influences of variations in local climate and Slave River hydrology

Topotecan-vincristine-doxorubicin in stage 4 high risk neuroblastoma patients failing to achieve a complete metastatic response to rapid COJEC : a SIOPEN study

Purpose : Metastatic response to induction therapy for high-risk neuroblastoma is a prognostic factor. In the International Society of Paediatric Oncology Europe Neuroblastoma (SIOPEN) HR-NBL-1 protocol, only patients with metastatic complete response (CR) or partial response (PR) with <= three abnormal skeletal areas on iodine 123-metaiodobenzylguanidine ([I-123] mIBG) scintigraphy and no bone marrow disease proceed to high dose therapy (HDT). In this study, topotecan-vincristine-doxorubicin (TVD) was evaluated in patients failing to achieve these criteria, with the aim of improving the metastatic response rate. Materials and Methods : Patients with metastatic high-risk neuroblastoma who had not achieved the SIOPEN criteria for HDT after induction received two courses of topotecan 1.5 mg/m(2)/day for 5 days, followed by a 48-hour infusion of vincristine, 2 mg/m(2), and doxorubicin, 45 mg/m(2). Results : Sixty-three patients were eligible and evaluable. Following two courses of TVD, four (6.4%) patients had an overall CR, while 28 (44.4%) had a PR with a combined response rate of 50.8% (95% confidence interval [CI], 37.9 to 63.6). Of these, 23 patients achieved a metastatic CR or a PR with <= 3 mIBG skeletal areas and no bone marrow disease (36.5%; 95% CI, 24.7 to 49.6) and were eligible to receive HDT. Toxicity was mostly haematological, affecting 106 of the 126 courses (84.1%; 95% CI, 76.5 to 90.0), and dose reduction was necessary in six patients. Stomatitis was the second most common nonhematological toxicity, occurring in 20 patients (31.7%). Conclusion : TVD was effective in improving the response rate of high-risk neuroblastoma patients after induction with COJEC enabling them to proceed to HDT. However, the long-term benefits of TVD needs to be determined in randomized clinical trials

From Isotopes to TK Interviews: Towards Interdisciplinary Research in Fort Resolution and the Slave River Delta, Northwest Territories

Evolving research in Fort Resolution and the Slave River Delta, Northwest Territories, aims to improve understanding of how the natural ecosystem functions and responds to various environmental stressors, as well as to enhance the stewardship of natural resources and the capacity of local residents to respond to change. We seek to integrate approaches that span the natural and social sciences and traditional knowledge understandings of change, employing a research design developed in response to the concerns of a northern community. In doing so, we have strived for a research process that is collaborative, interdisciplinary, policy-oriented, and reflective of northern priorities. These elements characterize the new northern research paradigm increasingly promoted by various federal funding agencies, northern partners, and communities. They represent a holistic perspective in the pursuit of solutions to address complex environmental and socioeconomic concerns about impacts of climate change and resource development on northern societies. However, efforts to fulfill the objectives of this research paradigm are associated with a host of on-the-ground challenges. These challenges include (but are not restricted to) developing effective community partnerships and collaboration and documenting change through interdisciplinary approaches. Here we provide an overview of the components that comprise our interdisciplinary research program and offer an accounting of our formative experiences in confronting these challenges

Statistical pairwise interaction model of stock market

Financial markets are a classical example of complex systems as they comprise many interacting stocks. As such, we can obtain a surprisingly good description of their structure by making the rough simplification of binary daily returns. Spin glass models have been applied and gave some valuable results but at the price of restrictive assumptions on the market dynamics or others are agent-based models with rules designed in order to recover some empirical behaviours. Here we show that the pairwise model is actually a statistically consistent model with observed first and second moments of the stocks orientation without making such restrictive assumptions. This is done with an approach based only on empirical data of price returns. Our data analysis of six major indices suggests that the actual interaction structure may be thought as an Ising model on a complex network with interaction strengths scaling as the inverse of the system size. This has potentially important implications since many properties of such a model are already known and some techniques of the spin glass theory can be straightforwardly applied. Typical behaviours, as multiple equilibria or metastable states, different characteristic time scales, spatial patterns, order-disorder, could find an explanation in this picture.Comment: 11 pages, 8 figure

One-dimensional Disordered Density Waves and Superfluids: The Role of Quantum Phase Slips and Thermal Fluctuations

The low temperature phase diagram of 1D disordered quantum systems like charge or spin density waves, superfluids and related systems is considered by a full finite T renormalization group approach, presented here for the first time. At zero temperature the consideration of quantum phase slips leads to a new scenario for the unpinning (delocalization) transition. At finite T a rich cross-over diagram is found which reflects the zero temperature quantum critical behavior.Comment: 4 pages, 2 figure

Accumulation of the common mitochondrial DNA deletion induced by ionizing radiation

AbstractPoint mutations and deletions in mitochondrial DNA (mtDNA) accumulate as a result of oxidative stress, including ionizing radiation. As a result, dysfunctional mitochondria suffer from a decline in oxidative phosphorylation and increased release of superoxides and other reactive oxygen species (ROS). Through this mechanism, mitochondria have been implicated in a host of degenerative diseases. Associated with this type of damage, and serving as a marker of total mtDNA mutations and deletions, the accumulation of a specific 4977-bp deletion, known as the common deletion (Δ-mtDNA4977), takes place. The Δ-mtDNA4977 has been reported to increase with age and during the progression of mitochondrial degeneration. The purpose of this study was to investigate whether ionizing radiation induces the formation of the common deletion in a variety of human cell lines and to determine if it is associated with cellular radiosensitivity. Cell lines used included eight normal human skin fibroblast lines, a radiosensitive non-transformed and an SV40 transformed ataxia telangiectasia (AT) homozygous fibroblast line, a Kearns Sayre Syndrome (KSS) line known to contain mitochondrial deletions, and five human tumor lines. The Δ-mtDNA4977 was assessed by polymerase chain reaction (PCR). Significant levels of Δ-mtDNA4977 accumulated 72 h after irradiation doses of 2, 5, 10 or 20 Gy in all of the normal lines with lower response in tumor cell lines, but the absolute amounts of the induced deletion were variable. There was no consistent dose–response relationship. SV40 transformed and non-transformed AT cell lines both showed significant induction of the deletion. However, the five tumor cell lines showed only a modest induction of the deletion, including the one line that was deficient in DNA damage repair. No relationship was found between sensitivity to radiation-induced deletions and sensitivity to cell killing by radiation