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关键词： Cotorsion pairs   Differential graded algebras and modules   Direct limit closure   Dualizable objects   Locally finitely presented categories   Semi-flat objects  

摘要： In this paper, we define what it means for an object in an abstract module category to be dualizable and we give a homological description of the direct limit closure of the dualizable objects. Our description recovers existing results of Govorov and Lazard, Oberst and Rohrl, and Christensen and Holm. When applied to differential graded modules over a differential graded algebra, our description yields that a DG-module is semi-flat if and only if it can be obtained as a direct limit of finitely generated semi-free DG-modules. We obtain similar results for graded modules over graded rings and for quasi-coherent sheaves over nice schemes.

关键词： Black-White inequality   categorical inequality   disproportionality   discipline   special education   Gifted and Talented   Advanced Placement  

摘要： We characterize the extent to which Black-White gaps for multiple educational outcomes are linked across school districts in the United States. Gaps in disciplinary action, grade-level retention, classification into special education and Gifted and Talented, and Advanced Placement course-taking are large in magnitude and correlated. Racial differences in family income and parent education are strikingly consistent predictors of these gaps, and districts with large gaps in one outcome are likely to have large gaps in another. Socioeconomic and segregation variables explain 1.7 to 3.5 times more variance for achievement relative to nonachievement outcomes. Systemic patterns of racial socioeconomic inequality drive inequalities across multiple educational outcomes;however, discretionary policies at local levels are more influential for nonachievement outcomes.

关键词： Quantum group   Unitary easy quantum group   Unitary group   Half-liberation   Tensor category   Two-colored partition   Partition of a set   Category of partitions  

摘要： We classify certain categories of partitions of finite sets subject to specific rules on the coloring of points and the sizes of blocks. More precisely, we consider pair partitions such that each block contains exactly one white and one black point when rotated to one line;however, crossings are allowed. There are two families of such categories, the first of which is indexed by cyclic groups and is covered in the present article;the second family will be the content of a follow-up article. Via a Tannaka-Krein result, the categories in the two families correspond to easy quantum groups interpolating the classical unitary groupUnand Wang's free unitary quantum groupUn+ In fact, they are all half-liberated in some sense and our results imply that there are many more half-liberation procedures than previously expected. However, we focus on a purely combinatorial approach leaving quantum group aspects aside.

关键词： Cross-modal retrieval   Matrix factorization   Hash  

摘要： Due to the emergence and development of big data, cross-modal hash retrieval has become progressively more important in large-scale multi-modal retrieval tasks depending on its accuracy and efficiency. It completes the retrieval task in a common low-dimensional space by finding a common semantic space for heterogeneous data of different modalities. Recently, many works have concentrated on supervised cross-modal hashing and achieved higher retrieval accuracy. However, there are still many challenges in how to maintain the local geometric structure of the original space in the public space and how to use the supervision information efficiently. To deal with such issues, this paper proposes a hash retrieval method that incorporates supervised information based on matrix factorization (LCSMFH) by maintain the inter-modal and the intra-modal similarity in the original space and make the most of the label information to improve the retrieval task effect. Through experiments on two benchmark data sets, our method is more effective and outperforms state-of-the-art methods. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Controlled Human Infection (CHI)   Controlled Human Malaria Infection   human challenge trials   pediatric research   research ethics  

摘要： Controlled human infection (CHI) models have been developed for numerous pathogens in order to better understand disease processes and accelerate drug and vaccine testing. In the past, some researchers conducted highly controversial CHIs with vulnerable populations, including children. Ethical frameworks for CHIs now recommend vulnerable populations be excluded because they cannot consent to high risk research. In this paper we argue that CHI studies span a wide spectrum of benefit and risk, and that some CHI studies may involve minimal risk. The categorical exclusion of children from CHIs therefore departs from the standard approach to evaluating research risks, as international regulations and ethical guidance for pediatric research generally permit non-beneficial research with low risks. The paradigm in research ethics has also shifted from focusing on protecting vulnerable participants to recognizing that inclusion can be important as a matter of justice, providing new reasons to question this default exclusion of children from CHIs. Recognizing that pediatric CHIs can raise complex ethical issues and are easy to sensationalize in ways that may threaten the public's trust in research and sponsor institutions, we conclude by describing additional complexities that must be addressed before pediatric CHIs beyond licensed vaccine studies might be ethically acceptable.

关键词： Quantum computing   Algebraic lambda-calculus   Categorical semantics  

摘要： Lambda-S is an extension to first-order lambda calculus unifying two approaches of noncloning in quantum lambda-calculi. One is to forbid duplication of variables, while the other is to consider all lambda-terms as algebraic linear functions. The type system of Lambda-S has a constructor S such that a type A is considered as the base of a vector space while S( A) is its span. Lambda-S can also be seen as a language for the computational manipulation of vector spaces: The vector spaces axioms are given as a rewrite system, describing the computational steps to be performed. In this paper we give an abstract categorical semantics of Lambda-S* (a fragment of Lambda-S), showing that S can be interpreted as the composition of two functors in an adjunction relation between a Cartesian category and an additive symmetric monoidal category. The right adjoint is a forgetful functorU, which is hidden in the language, and plays a central role in the computational reasoning.

关键词： 16D90   16G10   18E30 (primary)  

摘要： We give two proofs of the following theorem and a partial generalization: if a finite-dimensional algebraAis derived equivalent to a smooth projective scheme, then any derived equivalence betweenAand another algebraBis standard, that is, isomorphic to the derived tensor functor by a two-sided tilting complex. The main ingredients of the proofs are as follows: (1) between the derived categories of two module categories, liftable functors coincide with standard functors;(2) any derived equivalence between a module category and an abelian category is uniquely factorized as the composition of a pseudo-identity and a liftable derived equivalence;(3) the derived category of coherent sheaves on a certain class of projective schemes is triangle-objective, that is, any triangle autoequivalence on it, which preserves the isomorphism classes of all objects, is necessarily isomorphic to the identity functor.

关键词： Atlantic salmon   fish length   imaging sonar   measurement error   population assessment  

摘要： Imaging sonars are used around the world for fish population monitoring. The accuracy of the length measurements has been reported in multiple studies for relatively short (<15 m) ranges and high image resolution. However, imaging sonars are often used at longer ranges (i.e., >15 m) where the images produced from sonar returns become less detailed. The accuracy of the length measurements from the Adaptive Resolution Imaging Sonar (ARIS) was tested by releasingn= 69 known-sized adult Atlantic salmon (Salmo salar) directly into the sonar field at ranges between 15 and 29 m, and measuring their echoes manually by four users and semi-automatically using a computer workflow in Echoview software. Overall, the length measurements were very variable: compared to true (fork) lengths, the mean of differences varied between -9.9 cm and 7.8 cm in the human-generated datasets, and between -42.8 cm and -20 cm in the computer-generated dataset. In addition, the length measurements in different datasets were only in poor or moderate agreement with each other (intraclass correlation <0.61). Contrary to our expectations, the distance from the transducer or the subjectively assessed echo quality did not have an effect on the measurement accuracy in most of the datasets and when it did, the effect was not systematic between the datasets. Therefore, a size class and length prediction model was implemented in a Bayesian framework to group salmon into two size categories: One-Sea-Winter (<63 cm) and Multi-Sea-Winter (>= 63 cm) groups. The model correctly predicted the size category in 83% of the fish in the computer-generated dataset and ranged from 68% to 74% in the human-generated datasets. We conclude that fish length measurements derived from long-range imaging sonar data should be used with caution, but post-processing can improve the usefulness of the data for specific purposes, such as adult Atlantic salmon population monitoring.

关键词： Colour cognition   Colour vision   Crowdsourcing   Achromatic   Primary   Basic  

摘要： A range of explanations have been advanced for the systems of colour names found in different languages. Some explanations give special, fundamental status to a subset of colour categories. We argue that a subset of colour categories, if fundamental, will be coherent - meaning that a non-trivial criterion distinguishes them from the other colour categories. We test the coherence of subsets of achromatic (white, black and grey), primary (white, black, red, green, yellow, blue) and basic (primaries plus brown, orange, purple, pink and grey) colour categories in English. Criteria for defining colour categories were expressed in terms of behavioural, linguistic and geometric features derived from colour naming and linguistic usage data;and were discovered using machine learning methods. We find that achromatic and basic colour categories are coherent subsets but not primaries. These results support claims that the basic colour categories have special status, and undermine claims about the fundamental role of primaries in colour naming systems.