4,947 research outputs found
Improving Wildflower Longevity in Roadside Seeding Areas
Re-vegetation efforts on bare roadsides of newly-constructed highways are primarily focused on the stabilization of soil to reduce rates of erosion. The Nebraska Department of Transportation (NDOT) seeds roadsides with a diverse mixture of grasses and wildflowers for site stabilization as well as to enhance the visual quality of roadsides. Although grasses dominate roadside plantings in terms of cover and density, wildflowers are largely responsible for the visual enhancement of recently-seeded roadsides. In addition to the visual component, wildflowers provide essential ecological functions on roadsides. Wildflowers improve water and nutrient cycling in the compacted roadside soils by increasing water infiltration and nutrient availability. Leguminous wildflower species increase nitrogen content of soil. The variability of wildflower leaf size, shape and orientation provides a more continuous soil cover than grass alone. The diversity of wildflower growth habits and life cycles also allows for a greater range of stand establishment and persistence when compared to sites seeded to grasses alone. This article presents strategies for increasing wildflower success in roadside plantings
Quasirandomness in hypergraphs
An -vertex graph of edge density is considered to be quasirandom
if it shares several important properties with the random graph . A
well-known theorem of Chung, Graham and Wilson states that many such `typical'
properties are asymptotically equivalent and, thus, a graph possessing one
such property automatically satisfies the others.
In recent years, work in this area has focused on uncovering more quasirandom
graph properties and on extending the known results to other discrete
structures. In the context of hypergraphs, however, one may consider several
different notions of quasirandomness. A complete description of these notions
has been provided recently by Towsner, who proved several central equivalences
using an analytic framework. We give short and purely combinatorial proofs of
the main equivalences in Towsner's result.Comment: 19 page
The Impact of Sexual Abuse and How Children Cope: Different Perspectives from Caretakers and Children
Child sexual abuse is a complicated stressor with a broad range of associated symptoms. It has been suggested that the coping techniques children utilize may act as a mediating variable in the relationship between child sexual abuse and subsequent difficulties. Until recently, child sexual abuse sequelae were assessed in a piecemeal fashion, with individual tests for each symptom domain and reporter. However, recent developments in the area of trauma assessment have provided researchers with complementary caretaker- and self-report measures to assess a broad range of trauma-related symptoms (i.e., the Trauma Symptom Checklist for Young Children [TSCYC] and the Trauma Symptom Checklist for Children [TSCC], respectively). This project utilized the intake assessment data from children who were beginning psychotherapy services subsequent to sexual abuse. The TSCYC is a relatively new measure, therefore, Study 1 evaluated its internal consistency (N=308), the correlation between the caretaker- and self-report measures (N=135), and the convergent validity of the TSCYC with other caretaker-report measures of children¿s symptoms (N=135). The results indicated that the TSCYC has good internal consistency and convergent validity. The inter-correlation of the TSCYC and TSCC is quite low and consistent with other studies attempting to understand multi-informant assessment processes. Children and their caretakers describe very different pictures when asked about the children¿s difficulties. Study 2 (N=98) then evaluated the relationship between children¿s coping style as assessed by the KIDCOPE and trauma-related symptoms as reported by the children themselves and their caretakers. Overall, more external coping behaviors were associated with an increase in caretaker-reported symptoms, but internal coping was associated with more self-reported symptoms among children between the ages of eight and twelve years. The implications of these findings and future directions for research are discussed
Can the fast bone loss in osteoporotic and osteopenic patients be stopped with active vitamin D metabolites?
The aim of this study was to evaluate whether fast trabecular bone loss in osteoporotic and osteopenic patients can effectively be treated with active vitamin D metabolites. Thirty-one osteoporotic and osteopenic patients were monitored between 4 and 22 months before and between 8 and 18 months during the treatment. Fast bone losers were designated as osteoporotic or osteopenic patients with a loss of trabecular bone density in the radius of 3% or more calculated for 1 year. For this differentiation, the high precise peripheral quantitative computed tomography system (DENSISCAN 1000) was used (reproducability 0.3% in mixed collectives). The pretreatment loss and the "gain” under treatment with active vitamin D metabolites was calculated for 1 year. The treatment consisted of either 0.5 μg calcitriol daily or 1 μg of alfacalcidol daily. Before treatment, the trabecular bone loss in the radius/year was −6.6 ± 0.5% (mean ± SEM). After treatment with vitamin D metabolites, the trabecular bone gain in the radius/year was 0.01 ± 0.6% (mean ± SEM). The difference was highly significant (P < 0.001). In contrast to this, the loss of cortical bone density before treatment was −1.8 ± 0.3% (mean ± SEM) and the reduced loss after treatment −0.2 ± 0.4% (mean ± SEM), both values calculated for 1 year. This difference was less significant (P < 0.05). This study shows that the treatment with active vitamin D metabolites is very effective in slowing fast trabecular bone loss in osteoporotic and osteopenic patient
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