共查询到20条相似文献,搜索用时 9 毫秒
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Loretta Niebur Walker 《Arts Education Policy Review》2013,114(4):189-200
This is the first of two articles reporting the results of a study by the author regarding the status of elementary music education in the state of Utah. This article focuses on how elementary music programs are structured (regular instruction with a music specialist, truncated programs, delegated programs, no formal music instruction, no music instruction). Factors that shape those structures are also addressed. While over 90 percent of elementary schools in the United States provide regular music instruction taught by certified music specialists to over 90 percent of their student populations, less than 10 percent of Utah's elementary population receives such instruction. Nearly half of the elementary students in the state receive no designated music instruction other than that provided by their regular elementary classroom teachers. The influence of budget constraints, school funding policies, No Child Left Behind, other accountability measures, high-stakes testing, urban/rural populations, and demographics are highlighted. Policy considerations are discussed. 相似文献
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Cellulose biosynthesis is one of the most important biochemical processes in plant biology. Despite the considerable progress made during the last decade, numerous fundamental questions related to this key process in plant development are outstanding. Numerous models have been proposed through the years to explain the detailed molecular events of cellulose biosynthesis. Almost all models integrate solid experimental data with hypotheses on several of the steps involved in the process. Speculative models are most useful to stimulate further research investigations and bring new exciting ideas to the field. However, it is important to keep their hypothetical nature in mind and be aware of the risk that some undemonstrated hypotheses may progressively become admitted. In this review, we discuss the different steps required for cellulose formation and crystallization, and highlight the most important specific aspects that are supported by solid experimental data. 相似文献
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Cellulose biosynthesis is one of the most important biochemical processes in plant biology. Despite the considerable progress made during the last decade, numerous fundamental questions related to this key process in plant development are outstanding. Numerous models have been proposed through the years to explain the detailed molecular events of cellulose biosynthesis. Almost all models integrate solid experimental data with hypotheses on several of the steps involved in the process. Speculative models are... 相似文献
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1. Many drugs used to treat psychiatric disorders contain a chiral center or a center of unsaturation and are marketed as a mixture of the resultant enantiomers or geometric isomers, respectively. These enantiomers or geometric isomers may differ markedly with regard to their pharmacodynamic and/or pharmacokinetic properties.2. Examples of the effects of chiral centers or geometric centers on such properties are given for drugs from the following classes: antidepressants (tricyclics, selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, viloxazine, bupropion, trazodone, mianserin, venlaflaxine); benzodiazepines, zoplicone, and antipsychotics.3. As described in this review, there are several notable examples of psychiatric drugs currently available where the individual enantiomers or geometric isomers differ considerably with regard to factors such as effects on amine transport systems, interactions with receptors and metabolizing enzymes, and clearance rates from the body. Indeed, relatively recent developments in analytical and preparative resolution of racemic and geometric drug mixtures and increased interest in developing new drugs which interact with specific targets, which have been described in detail at the molecular level, have resulted in increased emphasis on stereochemistry in drug development. 相似文献
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Martine Van Puyvelde Gerrit Loots Pol Vanfleteren Joris Meys David Simcock Nathalie Pattyn 《PloS one》2014,9(9)
This study examined the effects of tonal and atonal music on respiratory sinus arrhythmia (RSA) in 40 mothers and their 3-month-old infants. The tonal music fragment was composed using the structure of a harmonic series that corresponds with the pitch ratio characteristics of mother–infant vocal dialogues. The atonal fragment did not correspond with a tonal structure. Mother–infant ECG and respiration were registered along with simultaneous video recordings. RR-interval, respiration rate, and RSA were calculated. RSA was corrected for any confounding respiratory and motor activities. The results showed that the infants’ and the mothers’ RSA-responses to the tonal and atonal music differed. The infants showed significantly higher RSA-levels during the tonal fragment than during the atonal fragment and baseline, suggesting increased vagal activity during tonal music. The mothers showed RSA-responses that were equal to their infants only when the infants were lying close to their bodies and when they heard the difference between the two fragments, preferring the tonal above the atonal fragment. The results are discussed with regard to music-related topics, psychophysiological integration and mother-infant vocal interaction processes. 相似文献
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Ingegerd A. Mejàre Gunilla Klingberg Frida K. Mowafi Christina Stecksén-Blicks Svante H. A. Twetman Sofia H. Tran?us 《PloS one》2015,10(2)
ObjectivesTo identify, appraise and summarize existing knowledge and knowledge gaps in practice-relevant questions in pediatric dentistry.MethodsA systematic mapping of systematic reviews was undertaken for domains considered important in daily clinical practice. The literature search covered questions in the following domains: behavior management problems/dental anxiety; caries risk assessment and caries detection including radiographic technologies; prevention and non-operative treatment of caries in primary and young permanent teeth; operative treatment of caries in primary and young permanent teeth; prevention and treatment of periodontal disease; management of tooth developmental and mineralization disturbances; prevention and treatment of oral conditions in children with chronic diseases/developmental disturbances/obesity; diagnosis, prevention and treatment of dental erosion and tooth wear; treatment of traumatic injuries in primary and young permanent teeth and cost-effectiveness of these interventions. Abstracts and full text reviews were assessed independently by two reviewers and any differences were solved by consensus. AMSTAR was used to assess the risk of bias of each included systematic review. Reviews judged as having a low or moderate risk of bias were used to formulate existing knowledge and knowledge gaps.ResultsOut of 81 systematic reviews meeting the inclusion criteria, 38 were judged to have a low or moderate risk of bias. Half of them concerned caries prevention. The quality of evidence was high for a caries-preventive effect of daily use of fluoride toothpaste and moderate for fissure sealing with resin-based materials. For the rest the quality of evidence for the effects of interventions was low or very low.ConclusionThere is an urgent need for primary clinical research of good quality in most clinically-relevant domains in pediatric dentistry. 相似文献
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Single-molecule force spectroscopy makes it possible to measure the mechanical strength of single noncovalent receptor-ligand-type bonds. A major challenge in this technique is to ensure that measurements reflect bonds between single biomolecules because the molecules cannot be directly observed. This perspective evaluates different methodologies for identifying and reducing the contribution of multiple molecule interactions to single-molecule measurements to help the reader design experiments or assess publications in the single-molecule force spectroscopy field. We apply our analysis to the large body of literature that purports to measure the strength of single bonds between biotin and streptavidin as a demonstration that measurements are only reproducible when the most reliable methods for ensuring single molecules are used. 相似文献
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Managing terminal lake elevation and salinity are emerging problems worldwide. We contribute to terminal lake management research by quantitatively assessing water and salt flow for Utah’s Great Salt Lake. In 1959, Union Pacific Railroad constructed a rock-filled causeway across the Great Salt Lake, separating the lake into a north and south arm. Flow between the two arms was limited to two 4.6 meter wide rectangular culverts installed during construction, an 88 meter opening (referred to locally as a breach) installed in 1984, and the semi porous material of the causeway. A salinity gradient developed between the two arms of the lake over time because the south arm receives approximately 95% of the incoming streamflow entering Great Salt Lake. The north arm is often at, or near, salinity saturation, averaging 317 g/L since 1966, while the south is considerably less saline, averaging 142 g/L since 1966. Ecological and industrial uses of the lake are dependent on long-term salinity remaining within physiological and economic thresholds, although optimal salinity varies for the ecosystem and between diverse stakeholders. In 2013, Union Pacific Railroad closed causeway culverts amid structural safety concerns and proposed to replace them with a bridge, offering four different bridge designs. As of summer 2015, no bridge design has been decided upon. We investigated the effect that each of the proposed bridge designs would have on north and south arm Great Salt Lake elevation and salinity by updating and applying US Geological Survey’s Great Salt Lake Fortran Model. Overall, we found that salinity is sensitive to bridge size and depth, with larger designs increasing salinity in the south arm and decreasing salinity in the north arm. This research illustrates that flow modifications within terminal lakes cannot be separated from lake salinity, ecology, management, and economic uses. 相似文献
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《Anthrozo?s》2013,26(4):485-503
ABSTRACTThis article presents an analysis of data from over 200 accounts of, and responses to questions about, how animals feature in people's lives. The accounts were generated by a Mass Observation Project (MOP) directive on “Animals and Humans.” The MOP, based at a UK university, sends out two or three directives a year, asking correspondents to write in response to a series of questions and prompts. The “Animals and humans” directive began with the question, “What do animals mean to you?” followed by a range of prompts about respondents' experiences of animals. The paper is specifically concerned with issues of how language both reflects and contributes to typologies of living creatures. It presents a qualitative analysis of some of the themes that emerged from responses to the directive, as well as a more quantitative analysis of the words chosen by respondents to denote different kinds of animals. Using these different methodological approaches, it focuses on how moral ambiguity is expressed and the ways in which categories and meanings shift depending on linguistic context. These methods complement each other, with the computer-assisted linguistic analysis providing a different and more quantitative method of revealing aspects of people's values, attitudes, and assumptions as they report on the role of animals in their lives. Overall, the paper shows how a corpus linguistic analysis can demonstrate the permeability of categories and boundaries, and the moral ambiguity toward animals that is revealed in the way language is used. 相似文献
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Despite important advances in ecological knowledge of Mediterranean‐type ecosystems, advances in restoration ecology have not seen a parallel increase in these systems. Although some concepts such as positive plant–plant interaction (facilitation) have received attention in the restoration ecology community, others such as phenotypic plasticity have not. Some concepts (e.g., environmental heterogeneity) are mature enough for a wide use in restoration, whereas available knowledge on others (e.g., facilitation, plasticity) is less conclusive. However, the scientific knowledge is in general enough to significantly improve the guidelines for restoration of Mediterranean ecosystems. Our review suggests that (1) the extent of facilitation in dry ecosystems is partially understood, with supporting, but somewhat contradictory empirical evidence for its potential use in restoration; (2) the influence of habitat heterogeneity on plant performance and plasticity is only beginning to be understood, with a strong bias toward patterns of structural heterogeneity and negligible information on functional heterogeneity; and (3) sound evaluations of phenotypic plasticity might be useful to increase the success of restoration practices in patchy Mediterranean environments. Future global change scenarios involving temperature rise, reduced precipitation, increased frequency of extreme climatic events, and important land use changes and fragmentation must be particularly considered when restoring Mediterranean ecosystems. Further research on how to incorporate results on facilitation, environmental heterogeneity, and plasticity within a global change framework is clearly needed. 相似文献
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Our study explores inhibitory control across a range of widely recognised memory and behavioural tasks. Eighty-seven never-depressed participants completed a series of tasks designed to measure inhibitory control in memory and behaviour. Specifically, a variant of the selective retrieval-practice and the Think/No-Think tasks were employed as measures of memory inhibition. The Stroop-Colour Naming and the Go/No-Go tasks were used as measures of behavioural inhibition. Participants completed all 4 tasks. Task presentation order was counterbalanced across 3 separate testing sessions for each participant. Standard inhibitory forgetting effects emerged on both memory tasks but the extent of forgetting across these tasks was not correlated. Furthermore, there was no relationship between memory inhibition tasks and either of the main behavioural inhibition measures. At a time when cognitive inhibition continues to gain acceptance as an explanatory mechanism, our study raises fundamental questions about what we actually know about inhibition and how it is affected by the processing demands of particular inhibitory tasks. 相似文献
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Yve Stoebel-Richter Kristina Geue Ada Borkenhagen Elmar Braehler Kerstin Weidner 《PloS one》2012,7(12)
Objective
The use of reproductive medical treatments has become increasingly routine in recent years. This paper reports on a study of how different aspects of modern reproductive medicine are perceived by the German population.Design
Findings from a nationally representative sample of 2110 men and women aged 18 to 50 are presented. Participants responded to a questionnaire seeking self-report information about attitudes and knowledge regarding different aspects of reproductive medicine.Results
The majority of respondents had already heard or read something about reproductive medicine; knowledge gaps were prevalent in men and individuals with lower levels of education. The decrease in female fertility usually was underestimated, whereas both the number of involuntarily childless couples and the success rate of reproductive medical treatment were overestimated. One-third of participants would make use of reproductive medicine to have their own child.Conclusion
This study revealed inadequacies in the knowledge of the German general population regarding reproductive medicine. Despite the low interest and poor knowledge of the topic, a broad acceptance of reproductive medical methods was reported. The results illustrate the need for adequate information transfer regarding female fertility as well as success rate and risks of reproductive medical interventions. 相似文献17.
Robert M. Hazen 《Evolution》2010,3(2):198-205
Earth scientists have devised many complementary and consistent techniques to estimate the ages of geologic events. Annually deposited layers of sediments or ice document hundreds of thousands of years of continuous Earth history. Gradual rates of mountain building, erosion of mountains, and the motions of tectonic plates imply hundreds of millions of years of change. Radiometric dating, which relies on the predictable decay of radioactive isotopes of carbon, uranium, potassium, and other elements, provides accurate age estimates for events back to the formation of Earth more than 4.5 billion years ago. These and other dating techniques are mutually consistent and underscore the reality of “deep time” in Earth history. 相似文献
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The hollow-face illusion refers to the finding that people typically perceive a concave (hollow) mask as being convex, despite the presence of binocular disparity cues that indicate the contrary. Unlike other illusions of depth, recent research has suggested that the eyes tend to converge at perceived, rather than actual, depths. However, technical and methodological limitations prevented one from knowing whether disparity cues may still have influenced vergence. In the current study, we presented participants with virtual normal or hollow masks and asked them to fixate the tip of the face's nose until they had indicated whether they perceived it as pointing towards or away from them. The results showed that the direction of vergence was indeed determined by perceived depth, although vergence responses were both somewhat delayed and of smaller amplitude (by a factor of about 0.5) for concave than convex masks. These findings demonstrate how perceived depth can override disparity cues when it comes to vergence, albeit not entirely. 相似文献
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