5,651 research outputs found
THE EFFECT OF A FOREST CONSERVATION REGULATION ON THE VALUE OF SUBDIVISIONS IN MARYLAND
Profit-maximizing land developers are hypothesized to configure subdivisions to minimize the effects of a conservation regulation on developed land values, subject to their expectations about the demand for developed building lots. This hypothesis allows development of a hedonic price model that takes account of production adjustments. The model is applied to the Maryland Forest Conservation Act, which requires developers to retain or plant trees on part of the developed land. Being exempt from the Act allows developers to gain more for the subdivisions they develop: the cost to regulated developers is about six percent of the per-acre price of developed land. The Act has significantly lowered per-acre developed land values in subdivisions with a mixture of townhouses and single-family dwellings. Costs of the Act are reduced by provisions that allow developers to plant trees offsite or to pay fees in lieu of planting.Resource /Energy Economics and Policy,
Bioassay of Solubilized \u3ci\u3eBacillus thuringiensis\u3c/i\u3e var. \u3ci\u3eisraelensis\u3c/i\u3e Crystals by Attachment to Latex Beads
Solubilized crystals of Bacillus thuringiensis var. israelensis were 7,000 times less toxic to Aedes aegypti larvae than intact crystals, presumably because mosquito larvae are filter feeders and selectively concentrate particles while excluding water and soluble molecules. A procedure is described whereby soluble toxins are adsorbed to 0.8- micrometer latex beads, with retention of toxicity. The latex bead assay should make it possible to analyze the structure and mode of action of the mosquito toxin
The representation of scientific research in the national curriculum and secondary school pupilsâ perceptions of research, its function, usefulness and value to their lives
Young peopleâs views on what research is, how it is conducted and whether it is important, influences the decisions they make about their further studies and career choices. In this paper we report the analysis of questionnaire data with a particular focus on pupil perceptions of research in the sciences and of the scientific method. The questionnaire was a 25-item Likert Scale (1-5) distributed to seven collaborating schools. We received 2634 returns from pupils across key stages 3, 4 and 5. We also asked teachers to complete the questionnaire in order to explore how they thought their pupils would respond. We received 54 teacher responses. Statistically significant differences in the responses were identified through a chi-square test on SPSS. As what is being taught influences secondary pupil views on research we also consider how the term âresearchâ appears in the national curriculum for England and Wales and the three main English exam boards. The main theoretical construct that informs our analysis of the questionnaire data and the national curriculum is Angela Brewâs 4-tier descriptor of perceptions of research (domino, trading, layer, journey). We use this framework in order to map what, when and how research is presented to school pupils in England and Wales. We also use this framework in order to highlight and discuss certain pupil views that emerged from the questionnaire data and which indicate areas where curriculum and pedagogy intervention may be necessary: pupils seem less confident in their understanding of research as involving the identification of a research question; and, they often see research as a means to confirm oneâs own opinion. They do however understand research as involving the generation of new knowledge and the collection of new data, such as interviews and questionnaires as well as laboratory work, field trips and library searches and they appear relatively confident in their statements about their ability to do research, their school experiences of research and the importance of research in their future career choice
A systematic review of naturalistic interventions in refugee populations
Naturalistic interventions with refugee populations examine outcomes following mental health interventions in existing refugee service organisations. The current review aimed to examine outcomes of naturalistic interventions and quality of the naturalistic intervention literature in refugee populations with the view to highlight the strengths and limitations of naturalistic intervention studies. Database search was conducted using the search terms ârefugeeâ, âasylum seekerâ, âtreatmentâ, âtherapyâ and âintervention. No date limitations were applied, but searches were limited to articles written in English. Seven studies were identified that assessed the outcome of naturalistic interventions on adult refugees or asylum seekers in a country of resettlement using quantitative outcome measures. Results showed significant variation in the outcomes of naturalistic intervention studies, with a trend towards showing decreased symptomatology at post-intervention. However, conclusions are limited by methodological problems of the studies reviewed, particularly poor documentation of intervention methods and lack of control in the design of naturalistic intervention studies. Further examination of outcomes following naturalistic interventions is needed with studies which focus on increasing the rigour of the outcome assessment process
Inoculum Size Effect in Dimorphic Fungi: Extracellular Control of Yeast-Mycelium Dimorphism in \u3ci\u3eCeratocystis ulmi\u3c/i\u3e
We studied the inoculum size effect in Ceratocystis ulmi, the dimorphic fungus that causes Dutch elm disease. In a defined glucose-proline-salts medium, cells develop as budding yeasts when inoculated at \u3e106 spores per ml and as mycelia when inoculated at type, age of the spores, temperature, pH, oxygen availability, trace metals, sulfur source, phosphorous source, or the concentration of glucose or proline. Similarly, it was not influenced by added adenosine, reducing agents, methyl donors, amino sugars, fatty acids, or carbon dioxide. Instead, growing cells excreted an unknown quorum-sensing factor that caused a morphological shift from mycelia to budding yeasts. This yeast-promoting effect is abolished if it is extracted with an organic solvent such as ethyl acetate. The quorum-sensing activity acquired by the organic solvent could be added back to fresh medium in a dosedependent fashion. The quorum-sensing activity in C. ulmi spent medium was specific for C. ulmi and had no effect on the dimorphic fungus Candida albicans or the photomorphogenic fungus Penicillium isariaeforme. In addition, farnesol, the quorum-sensing molecule produced by C. albicans, did not inhibit mycelial development of C. ulmi when present at concentrations of up to 100 ÎŒM. We conclude that the inoculum size effect is a manifestation of a quorum-sensing system that is mediated by an excreted extracellular molecule, and we suggest that quorum sensing is a general phenomenon in dimorphic fungi
The First Mid-infrared Detection of HNC in the Interstellar Medium: Probing the Extreme Environment toward the Orion Hot Core
We present the first mid-infrared (MIR) detections of HNC and H13CN in the interstellar medium, and numerous, resolved HCN rovibrational transitions. Our observations span 12.8 to 22.9 micron towards the hot core Orion IRc2, obtained with the Echelon-Cross-Echelle Spectrograph aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). Exceptional, ~5 km/s, resolution distinguishes individual rovibrational transitions of the HNC and HCN P, Q, and R branches; and the H13CN R branch. This allows direct measurement of the species' excitation temperatures, column densities, and relative abundances. HNC and H13CN exhibit a local standard rest velocity of -7 km/s that may be associated with an outflow from nearby radio source I and an excitation temperature of about 100 K. We resolve two velocity components for HCN, the primary component also being at -7 km/s with temperature 165 K. The hottest component, which had never before been observed, is at 1 km/s with temperature 309 K. This is the closest component to the hot core's centre measured to date. The derived 12C/13C=13 is below expectation for Orion's Galactocentric distance, but the derived HCN/HNC=72 is expected for this extreme environment. Compared to previous sub-mm and mm observations, our SOFIA line survey of this region shows that the resolved MIR molecular transitions are probing a distinct physical component and isolating the chemistry closest to the hot core
Observing Non-Gaussian Sources in Heavy-Ion Reactions
We examine the possibility of extracting non-Gaussian sources from
two-particle correlations in heavy-ion reactions. Non-Gaussian sources have
been predicted in a variety of model calculations and may have been seen in
various like-meson pair correlations. As a tool for this investigation, we have
developed an improved imaging method that relies on a Basis spline expansion of
the source functions with an improved implementation of constraints. We examine
under what conditions this improved method can distinguish between Gaussian and
non-Gaussian sources. Finally, we investigate pion, kaon, and proton sources
from the p-Pb reaction at 450 GeV/nucleon and from the S-Pb reaction at 200
GeV/nucleon studied by the NA44 experiment. Both the pion and kaon sources from
the S-Pb correlations seem to exhibit a Gaussian core with an extended,
non-Gaussian halo. We also find evidence for a scaling of the source widths
with particle mass in the sources from the p-Pb reaction.Comment: 16 pages, 15 figures, 5 tables, uses RevTex3.
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