250 research outputs found
A Study of Capability-Based Effect Systems
The problem of effect polymorphism is a major obstacle to wide adoption of effect systems in the programming community. The absence of effect systems reduces compiler optimization opportunities and disables effect constraints on APIs in parallel and distributed computations. This study shows that capability-based effect systems, equipped with stoic functions and free functions, can easily solve the problem of effect polymorphism without incurring notational burden on programmers. With this advantage, capability-based effect systems stand a better chance to be adopted by the programming community. The central idea of capability-based effect system is that a capability is required in order to produce side effects. If capabilities are passed as function parameters, by tracking capabilities in the type system we can track effects in the program. To ensure that capabilities are passed through function parameters, instead of being captured from the environment, we need to impose a variable-capturing discipline, stipulating that capa- bility variables cannot be captured. Functions observing the discipline are called stoic functions, while functions not observing the discipline are called free functions
Two approaches to portable macros
For any programming language that supports macros and has multiple implementations (each with different AST definitions), there is a common problem: how to make macros that operate on ASTs portable among different compiler implementations? Implementing portable macros is especially important for statically typed languages like Scala, as IDE vendors usually have different implementations of the language in order to support rich IDE features. Unportable macros compromise IDE features and degrade programming experience. We describe two approaches to the portability problem based on two different views on macros: (1) the tree-based approach, which views macros as operations on abstract syntax trees, solves the problem by defining standard abstract syntax trees; (2) the syntax-based approach, which views macros as operations on abstract syntax, solves the problem by defining standard abstract syntax. We show that the latter has significant practical advantages, especially in supporting semantic macros that use type information of ASTs to transform user code. Based on the idea, we implemented a new macro system, Gestalt, for the experimental Scala compiler, Dotty. The new implementation solves several long-standing problems of the current Scala macro system and demonstrates advantages over alternative approaches. Our solution has been adopted in the official new Scala macro system
A measurement model for real estate bubble size based on the panel data analysis : an empirical case study
Employing the fundamental value of real estate determined by the economic fundamentals,
a measurement model for real estate bubble size is established based on the panel data
analysis. Using this model, real estate bubble sizes in various regions in Japan in the late
1980s and in recent China are examined. Two panel models for Japan provide results,
which are consistent with the reality in the 1980s where a commercial land price bubble
appeared in most area and was much larger than that of residential land. This provides evidence
of the reliability of our model, overcoming the limit of existing literature with this
method. The same models for housing prices in China at both the provincial and city levels
show that contrary to the concern of serious housing price bubble in China, over-valuing in
recent China is much smaller than that in 1980s Japan.S1 File. Details of Data Sources.We acknowledge the support from the
following research projects: ÂȘA Study on Spatial
Effects of Regional Systemic Financial Risks Led by
Real Estate Market in Jiangsu ProvinceÂș
(15EYD004) from Social Science Scientific Fund of Jiangsu Province; ÂȘA Study on Regional Systemic
Financial Risks Led by Real Estate in ChinaÂș
(2016M591948) from China Post-doctor Scientific
Fund; ÂȘMethodology of Functional Data Mining with
Its Application in Financial MarketÂș (15YJCZH162)
from Humanities and Social Science Foundation of
Ministry of Education of China; ÂȘSailing PlanÂș from
China University of Mining & Technology.http://www.plosone.orgam2017Electrical, Electronic and Computer Engineerin
Psychic income associated with Shanghai tennis masters and residentsâ attitude
Using Shanghai Tennis Masters as an example, this study seeks to explore the psychic income associated with major sports events hosting and whether the psychic income would predict the attitudes of local residents toward events hosting. In addition, the moderating effect of sport involvement on the relationship between psychic income and attitude is also tested. In this study, a questionnaire survey is adopted. The structured questionnaire was developed based on 4 parts, including the demographics of the residents, involvement in the sport event, psychic income from the sport event, and their attitudes toward the sports event, there were 47 items in total. Data were collected from the local residents of Shanghai (including 16 districts or counties), as a result, 1,302 valid questionnaires were collected. A series of statistical analyses were conducted by using SPSS25.0 and AMOS 24.0 to examine the reliability and validity of the scales and to test the hypotheses. The results showed that the event has brought a significant level of psychic income to the local community, and the perceived psychic income would predict the attitudes of the residents toward the event hosting. The moderating effect of sports involvement on the relationship between psychic income and attitude is also confirmed
Foundations of Implicit Function Types
Implicit parameters are used pervasively in Scala and are also present in a number of other programming and theorem proving languages. This paper describes a generalization of implicit parameters as they are currently found in Scala to implicit function types. We motivate the construct by a series of examples and provide formal foundations that closely follow the semantics implemented by the Scala compiler
Resveratrol Pretreatment Improved Heart Recovery Ability of Hyperglycemic Bone Marrow Stem Cells Transplantation in Diabetic Myocardial Infarction by Down-Regulating MicroRNA-34a
AIM: To examine the effect of resveratrol (RSV) on bone marrow mesenchymal stem cells (BMSCs) under hyperglycemic conditions and on BMSCs transplantation in diabetic rats with myocardial infarction (MI).METHODS:In vitro, BMSCs were isolated from 3-week-old male Sprague Dawley (SD) rats and cultured under hyperglycemic conditions for up to 28 days. Cell viability was analyzed by cell counting kit-8 (CCK-8) assays. The expression of miR-34a was measured by RT-qPCR. Western blotting was used to examine the protein expression of SIRT1, P21, P16, VEGF and HIF-1α. A senescence-associated ÎČ-galactosidase assay was used to examine the senescence level of each group. In vivo, a diabetes model was established by feeding rats a high-sugar and high-fat diet for 8 weeks, injecting the animals with streptozotocin (STZ) and continuing high-sugar and high-fat feeding for 4 additional weeks. Then, left anterior descending coronary artery (LAD) cessation was used to established the myocardial infarction (MI) models. Each group of rats was transplanted with differentially preconditioned BMSCs after myocardial infarction. Ultrasound was used to analyze cardiac function 1 and 3 weeks after the operation, and frozen heart sections were used for immunohistochemical analysis, Masson staining and CD31 measurement. In addition, ELISA analysis of serum cytokine levels was performed.RESULTS: This study showed that the viability of BMSCs cultured under hyperglycemic conditions was decreased, the cells became senescent. Besides, an obviously increased in the expression of miR-34a was detected. Moreover, RSV preconditioning reduced the expression of miR-34a in BMSCs after high glucose stimulation and rejuvenated BMSCs under hyperglycemic conditions. Further analysis showed that the transplantation of RSV-BMSCs were benefit to heart recovery following infarction in diabetic rats, promoted proangiogenic factor release and increased arteriole and capillary densities.CONCLUSION: RSV rejuvenated BMSCs after chronic hyperglycemia-induced senescence by interacting with miR-34a and optimized the therapeutic effect of BMSCs on diabetes with myocardial infarction
Simplicitly: Foundations and Applications of Implicit Function Types
Understanding a program entails understanding its context; dependencies, configurations and even implementations are all forms of contexts. Modern programming languages and theorem provers offer an array of constructs to define contexts, implicitly. Scala offers implicit parameters which are used pervasively, but which cannot be abstracted over. This paper describes a generalization of implicit parameters to implicit function types, a powerful way to abstract over the context in which some piece of code is run. We provide a formalization based on bidirectional type-checking that closely follows the semantics implemented by the Scala compiler. To demonstrate their range of abstraction capabilities, we present several applications that make use of implicit function types. We show how to encode the builder pattern, tagless interpreters, reader and free monads and we assess the performance of the monadic structures presented
Global knowledge mapping and emerging trends in research between spasmolytic polypeptide-expressing metaplasia and gastric carcinogenesis: A bibliometric analysis from 2002 to 2022
BackgroundSpasmolytic polypeptide expression metaplasia (SPEM) occurs in the corpus of the stomach and is closely related to inflammations caused by H. pylori infection. Recently, SPEM was suggested as one of the dubious precancerous lesions of gastric cancer (GC). Thus, further research on SPEM cell transdifferentiation and its underlying mechanisms could facilitate the development of new molecular targets improving the therapeutics of GC. Using bibliometrics, we analyzed publications, summarized the research hotspots and provided references for scientific researchers engaged in related research fields.MethodsWe searched the Web of Science Core Collection (WoSCC) for publications related to SPEM-GC from 2002 to 2022. The VOSviewer, SCImago, CiteSpace and R software were used to visualize and analyze the data. Gene targets identified in the keyword list were analyzed for functional enrichment using the KEGG and GO databases.ResultsOf the 292 articles identified in the initial search, we observed a stable trend in SPEM-GC research but rapid growth in the number of citations. The United States was the leader in terms of quality publications and international cooperation among them. The total number of articles published by Chinese scholars was second to the United States. Additionally, despite its low centrality and average citation frequency, China has become one of the worldâs most dynamic countries in academics. In terms of productivity, Vanderbilt University was identified as the most productive institution. Further, we also observed that Gastroenterology was the highest co-cited journal, and Goldenring Jr. was the most prolific author with the largest centrality.ConclusionSPEM could serve as an initial step in diagnosing gastric precancerous lesions. Current hotspots and frontiers of research include SPEM cell lineage differentiation, interaction with H. pylori, disturbances of the mucosal microenvironment, biomarkers, clinical diagnosis and outcomes of SPEM, as well as the development of proliferative SPEM animal models. However, further research and collaboration are still required. The findings presented in this study can be used as reference for the research status of SPEM-GC and determine new directions for future studies
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