2,144 research outputs found
FOREWORD: Special Issue on Experimental Methods in Environmental, Natural Resource, and Agricultural Economics
Agricultural and Food Policy, Environmental Economics and Policy, Institutional and Behavioral Economics, Research Methods/ Statistical Methods,
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Do children use different forms of verbal rehearsal in serial picture recall tasks? A multi-method study
Use of verbal rehearsal is a key issue in memory development. However, we still lack detailed and triangulated information about the early development and the circumstances in which different forms of rehearsal are used. To further understand significant factors that affect children’s use of various forms of rehearsal, the present study involving 108 primary school children adopted a multi-method approach. It combined a carefully chosen word length effect method with a self-paced presentation time method to obtain behavioural indicators of verbal rehearsal. In addition, subsequent trial-by-trial self-reports were gathered. Word length effects in recall suggested that phonological recoding (converting images to names - a necessary precursor for rehearsal) took place, with evidence of more rehearsal among children with higher performance levels. According to self-paced presentation times, cumulative rehearsal was the dominant form of rehearsal only for children with higher spans on difficult trials. The combined results of self-paced times and word length effects in recall suggest that ‘naming’ as simple form of rehearsal was dominant for most children. Self-reports were in line with these conclusions. Additionally, children used a mixture of strategies with considerable intra-individual variability, yet strategy use was nevertheless linked to age as well as performance levels
"Cost Effective Conservation Planning: Twenty Lessons from Economics"
Economists advocate that the billions of public dollars spent on conservation should be allocated to achieve the largest possible social benefit. This is what we term “cost-effective conservation”-- a process that incorporates both benefits and costs that are measured with money. This controversial proposition has been poorly understood and not implemented by conservation planners. Drawing from evidence from the largest conservation programs in the United States, this paper seeks to improve the communication between economists and planners and overcome resistance to cost-effective conservation by addressing the open questions that likely drive skepticism among non-economists and by identifying best practices for project selection. We first delineate project-selection strategies and compare them to optimization. Then we synthesize the body of established research findings from economics into 20 practical lessons. Based on theory, policy considerations, and empirical evidence, these lessons illustrate the potential gains from improving practices related to cost-effective selection and also address how to overcome landowner-incentive challenges that face programs.conservation planning, cost-effectiveness, nonmarket valuation, benefit cost targeting, optimization, prioritization
Time-dependent Schr\"odinger equations having isomorphic symmetry algebras. I. Classes of interrelated equations
In this paper, we focus on a general class of Schr\"odinger equations that
are time-dependent and quadratic in X and P. We transform Schr\"odinger
equations in this class, via a class of time-dependent mass equations, to a
class of solvable time-dependent oscillator equations. This transformation
consists of a unitary transformation and a change in the ``time'' variable. We
derive mathematical constraints forthe transformation and introduce two
examples.Comment: LaTeX, 18 pages, new format, edite
Investigations into the Sarcomeric Protein and Ca2+-Regulation Abnormalities Underlying Hypertrophic Cardiomyopathy in Cats (Felix catus).
Hypertrophic cardiomyopathy (HCM) is the most common single gene inherited cardiomyopathy. In cats (Felix catus) HCM is even more prevalent and affects 16% of the outbred population and up to 26% in pedigree breeds such as Maine Coon and Ragdoll. Homozygous MYBPC3 mutations have been identified in these breeds but the mutations in other cats are unknown. At the clinical and physiological level feline HCM is closely analogous to human HCM but little is known about the primary causative mechanism. Most identified HCM causing mutations are in the genes coding for proteins of the sarcomere. We therefore investigated contractile and regulatory proteins in left ventricular tissue from 25 cats, 18 diagnosed with HCM, including a Ragdoll cat with a homozygous MYBPC3 R820W, and 7 non-HCM cats in comparison with human HCM (from septal myectomy) and donor heart tissue. Myofibrillar protein expression was normal except that we observed 20–44% MyBP-C haploinsufficiency in 5 of the HCM cats. Troponin extracted from 8 HCM and 5 non-HCM cat hearts was incorporated into thin filaments and studied by in vitro motility assay. All HCM cat hearts had a higher (2.06 ± 0.13 fold) Ca2+-sensitivity than non-HCM cats and, in all the HCM cats, Ca2+-sensitivity was not modulated by troponin I phosphorylation. We were able to restore modulation of Ca2+-sensitivity by replacing troponin T with wild-type protein or by adding 100 μM Epigallocatechin 3-gallate (EGCG). These fundamental regulatory characteristics closely mimic those seen in human HCM indicating a common molecular mechanism that is independent of the causative mutation. Thus, the HCM cat is a potentially useful large animal model
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Executive functioning and verbal fluency in children with language difficulties
This study provided a detailed analysis of verbal fluency in children with language difficulties, and examined the relative contributions of executive functioning (executive-loaded working memory, switching, inhibition) and language ability to verbal fluency performance. Semantic and phonemic fluency, language, and executive functioning tasks were completed by 41 children with specific language impairment (SLI) and 88 children with typical development. Children with SLI showed difficulties with most aspects of verbal fluency (rates of output, errors, switching) relative to typical children. Language ability predicted nearly every aspect of phonemic fluency performance and some aspects of semantic fluency performance. The relationships between verbal fluency and executive functioning were modest: inhibition was related to error scores on the phonemic fluency task, but relationships with executive-loaded working memory and switching were absent. Educationally, these results emphasise the underlying importance of language abilities in generation tasks like verbal fluency, but point to the importance of inhibition skills for error monitoring. Interventions to improve search and generation abilities have the potential to offer broader benefits in the classroom for children with language difficulties
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Executive functioning: Developmental consequences on adolescents with histories of maltreatment
Research suggests that children exposed to maltreatment have deficits in executive functioning (EF) but few studies have focused on the adolescent age group. We investigated whether maltreated adolescents had lower EF abilities compared to a group of non-maltreated adolescents. Forty adolescents with histories of child maltreatment, together with a comparison group of 40 non-maltreated adolescents matched for age, completed a comprehensive battery of EF tasks. Hierarchical multiple regression analyses, controlling for IQ, were carried out using each of the EF measures as dependent variables to examine group differences. Maltreated adolescents had significantly lower performance than non-maltreated adolescents on tasks assessing executive loaded working memory, fluency, and inhibition, although switching was not impaired. Emotional and behavioural difficulties (EBD) were included in additional regression analyses to examine whether these variables would explain the group differences. The inclusion of EBD variables had some effect on group differences, as expected, but did not eliminate them. These findings support the theory that impairments in EF may be one underlying reason why adolescents with histories of maltreatment struggle to cope both inside and outside the classroom
A biological and chemical approach to restoring water quality: A case study in an urban eutrophic pond
Efforts to improve water quality of eutrophic ponds often involve implementing changes to watershed management practices to reduce external nutrient loads. While this is required for long-term recovery and prevention, eutrophic conditions are often sustained through the recycling of internal nutrients already present within the waterbody. In particular, internal phosphorus bound to organic material and adsorbed to sediment has the potential to delay lake recovery for decades. Thus, pond and watershed management techniques are needed that not only reduce external nutrient loading but also mitigate the effects of internal nutrients already present. Therefore, our objective was to demonstrate a biological and chemical approach to remove and sequester nutrients present and entering an urban retention pond. A novel biological and chemical management technique was designed by constructing a 37 m2 (6.1 m × 6.1 m) floating treatment wetland coupled with a slow-release lanthanum composite inserted inside an airlift pump. The floating treatment wetland promoted microbial denitrification and plant uptake of nitrogen and phosphorus, while the airlift pump slowly released lanthanum to the water column over the growing season to reduce soluble reactive phosphorus. The design was tested at the microcosm and field scales, where nitrate-N and phosphate-P removal from the water column was significant (α = 0.05) at the microcosm scale and observed at the field scale. Two seasons of field sampling showed both nitrate-N and phosphate-P concentrations were reduced from 50 μg L–1 in 2020 to \u3c10 μg L–1 in 2021. Load calculations of incoming nitrate-N and phosphate-P entering the retention pond from the surrounding watershed indicate the presented biological-chemical treatment is sustainable and will minimize the effects of nutrient loading from nonpoint source pollution
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