The usual design-unbiased estimators in adaptive cluster sampling are easy to compute but are not functions of the minimal sufficient statistic and hence can be improved. Improved unbiased estimators obtained by conditioning on sufficient statistics—not necessarily minimal—are described. First, estimators that are as easy to compute as the usual design-unbiased estimators are given. Estimators obtained by conditioning on the minimal sufficient statistic which are more difficult to compute are also discussed. Estimators are compared in examples.
Guitar Making with an X-Carve CNC Router
Here come the robots. Although CNC routers are not yet at the Jetsons stage, we are far beyond the days when computer-driven tools were only in luthiers’ dreams, not their workshops. Mark French brings us up to date as he selects and installs an inexpensive machine in his home shop.
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- Award ID(s):
- 1700531
- PAR ID:
- 10252113
- Date Published:
- Journal Name:
- American lutherie
- ISSN:
- 1041-7176
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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null (Ed.)In citizen science, data stewards and data producers are often not the same people. When those who have labored on data collection are not in control of the data, ethical problems could arise from this basic structural feature. In this Perspective, we advance the proposition that stewarding data sets generated by volunteers involves the typical technical decisions in conventional research plus a suite of ethical decisions stemming from the relationship between professionals and volunteers. Differences in power, priorities, values, and vulnerabilities are features of the relationship between professionals and volunteers. Thus, ethical decisions about open data practices in citizen science include, but are not limited to, questions grounded in respect for volunteers: who decides data governance structures, who receives attribution for a data set, which data are accessible and to whom, and whose interests are served by the data use/re-use. We highlight ethical issues that citizen science practitioners should consider when making data governance decisions, particularly with respect to open data.more » « less
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This paper provides a cross-linguistic analysis of Mermaid Constructions in terms of Lexical Functional Grammar. Mermaid Constructions, coined by Tsunoda (2020), are grammaticalized monoclausal constructions in which a verb and a noun, sometimes with a copula, form a compound predicate. However, the work was chiefly descriptive, and the morphosyntactic nature of Mermaid Constructions in theoretical terms has not yet been explained. In this work, in opposition to Tsunoda’s (2020) hypothesis, the following points are shown: (1) Mermaid Constructions are not monoclausal but biclausal; (2) Mermaid Constructions do not comprise a compound predicate, but are control and raising with a nominal predicate; (3) these findings hold cross-linguistically.more » « less
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Recent assemblies by the T2T and VGP consortia have achieved significant accuracy but required a tremendous amount of effort and resources. More typical assembly efforts, on the other hand, still suffer both from misassemblies (joining sequences that should not be adjacent) and from underassemblies (not joining sequences that should be adjacent). To better understand the common algorithm-driven causes of these limitations, we investigated the unitig algorithm, which is a core algorithm at the heart of most assemblers. We prove that, contrary to popular belief, even when there are no sequencing errors, unitigs are not always safe (i.e., they are not guaranteed to be substrings of the sequenced genome). We also prove that the unitigs of a bidirected de Bruijn graph are different from those of a doubled de Bruijn graph and, contrary to our expectations, result in underassembly. Using experimental simulations, we then confirm that these two artifacts exist not only in theory but also in the output of widely used assemblers. In particular, when coverage is low, then even error-free data result in unsafe unitigs; also, unitigs may unnecessarily split palindromes in half if special care is not taken. To the best of our knowledge, this paper is the first to theoretically predict the existence of these assembler artifacts and confirm and measure the extent of their occurrence in practice.more » « less
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Despite persistent and extensive observations of crystals with chiral shapes, the mechanisms underlying their formation are not well understood. Although past studies suggest that chiral shapes can form because of crystallization in the presence of chiral additives, or because of an intrinsic tendency that stems from the crystal structure, there are many cases in which these explanations are not suitable or have not been tested. Here, an investigation of model tellurium nanocrystals provides insights into the chain of chirality transfer between crystal structure and shape. We show that this transfer is mediated by screw dislocations, and shape chirality is not an outcome of the chiral crystal structure or ligands.
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Accepted Manuscript1.0
- Journal Article:
- The DOI is not currently available.
