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Many Assumptions (many + assumption)

Distribution by Scientific Domains

Humanities and Social Sciences	40%

Selected Abstracts

Task-based language learning research: expecting too much or too little?

INTERNATIONAL JOURNAL OF APPLIED LINGUISTICS, Issue 3 2009
Pauline Foster
taakgericht taalleren; onderzoeksbetrouwbaarheid; implicaties voor het onderwijs; onderwijs aan docenten; evaluatie van docenten There are many assumptions about task-based language learning (TBLL) for which empirical support would be illuminating. Some of these are researchable and others are not, and it is important to distinguish between the two. Robust investigations into learning are not easy to design and should not necessarily be regarded as the pathfinder for language pedagogy, though critics sometimes may represent research into TBLL as claiming this role. This paper argues for a greater understanding of the scope of educational research, and a greater role for it in shaping best practice in classrooms. Er zijn veel veronderstellingen over taakgericht taal leren (tgtl) waarvoor empirische onderbouwing verhelderend zou zijn. Sommige van deze veronderstellingen vallen wel te onderzoeken maar andere niet , dit verschil is belangrijk. Het is niet makkelijk om degelijk onderzoek naar ,leren' te ontwerpen. Daarom moeten we dit niet zien als de enige juiste manier van onderzoek doen naar taalonderwijs, ook al doen critici soms als of onderzoek naar tgtl deze rol wil vervullen. Dit artikel pleit voor een beter begrip van het bereik van onderzoek naar onderwijs en wil bovendien dit soort onderzoek een grotere rol toekennen bij de ontwikkeling van ,best practices' voor de onderwijspraktijk. [source]

Effects of government programs to raise milk prices: Academic economists and public policy

AGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 4 2005
Daniel A. Sumner
The Northeast Dairy Compact benefited milk suppliers (and allied input suppliers) and harmed those on the fluid milk demand side in the Compact region, while having opposite impacts on these groups outside the Compact region. These simulation results leave many questions unanswered, but seem relatively robust. Simulations require many assumptions, but so do all other approaches to policy analysis. The specific policy question addressed and available data determine the most promising approach. In some cases, as with the evaluating effects of the Compact, a variety of approaches to policy analysis are complementary. [EconLit citations: Q18, Q13, L10, L43]. © 2005 Wiley Periodicals, Inc. Agribusiness 21: 473,476, 2005. [source]

Statistical hypothesis testing in intraspecific phylogeography: nested clade phylogeographical analysis vs. approximate Bayesian computation

MOLECULAR ECOLOGY, Issue 2 2009
ALAN R. TEMPLETON
Abstract Nested clade phylogeographical analysis (NCPA) and approximate Bayesian computation (ABC) have been used to test phylogeographical hypotheses. Multilocus NCPA tests null hypotheses, whereas ABC discriminates among a finite set of alternatives. The interpretive criteria of NCPA are explicit and allow complex models to be built from simple components. The interpretive criteria of ABC are ad hoc and require the specification of a complete phylogeographical model. The conclusions from ABC are often influenced by implicit assumptions arising from the many parameters needed to specify a complex model. These complex models confound many assumptions so that biological interpretations are difficult. Sampling error is accounted for in NCPA, but ABC ignores important sources of sampling error that creates pseudo-statistical power. NCPA generates the full sampling distribution of its statistics, but ABC only yields local probabilities, which in turn make it impossible to distinguish between a good fitting model, a non-informative model, and an over-determined model. Both NCPA and ABC use approximations, but convergences of the approximations used in NCPA are well defined whereas those in ABC are not. NCPA can analyse a large number of locations, but ABC cannot. Finally, the dimensionality of tested hypothesis is known in NCPA, but not for ABC. As a consequence, the ,probabilities' generated by ABC are not true probabilities and are statistically non-interpretable. Accordingly, ABC should not be used for hypothesis testing, but simulation approaches are valuable when used in conjunction with NCPA or other methods that do not rely on highly parameterized models. [source]

Critical reflections on practice: the changing roles of three physical geographers carrying out research in a developing country

AREA, Issue 1 2009
Jayalaxshmi Mistry
To date, discussions on positionality and the relationship with research collaborators have been very much in the human geography realm. In this paper, we explore issues of expertise, positionality, collaboration and participation from our perspective as physical geographers working in a developing country context. We trace our journey from identifying ourselves as top-down ,experts' to participatory ,facilitators', and the difficulties and dilemmas encountered during this journey as we coped with the contrasting challenges of academic demands and local necessities. Our experiences highlight the many assumptions we make about doing research in developing countries and the real lack of capacity in these places to undertake typical short-term research projects designed in the developed world. We conclude with a call for a longer term and deeper commitment by physical geographers to the people that we engage with in our research. [source]

New ways of looking at experimental phasing

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2003
Randy J. Read
In the original work by Blow and Crick, experimental phasing was formulated as a least-squares problem. For good data on good derivatives this approach works reasonably well, but we now attempt to extract more information from poorer data than in the past. As in many other crystallographic problems, the assumptions underlying the use of least squares for phasing are not satisfied, particularly for poor derivatives. The introduction of maximum likelihood (and more powerful computers) has led to substantial improvements. For computational convenience, these new methods still make many assumptions about the independence of different measurements and sources of error. A more general formulation for the probability distributions underlying likelihood-based methods for both experimental phasing and molecular-replacement phasing is reviewed. In the new formulation, all the structure factors associated with a particular hkl are considered to be related by a complex multivariate normal distribution. When it is assumed that certain errors are independent, the general formulation reduces to current likelihood targets. However, the new formulation makes the necessary assumptions more explicit and points the way to improving phasing using both isomorphous and anomalous differences. [source]