bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Oxidation of Benzyl Halides to Benzaldehydes by Phase Transfer Catalyzed Monochromate Ions in Non-Polar Solvents
Authors: Bijudas K. , Bashpa P.
Published: September 2020

Benzyl chloride, benzyl bromide and their para substituted derivatives were selectively oxidized to corresponding benzaldehydes by acidified monochromate in toluene and ethyl acetate with the help of phase transfer catalysts like tetrabutylphosphonium bromide (TBPB), tetrabutylammonium bromide (TBAB), tetrabutylammonium hydrogen sulphate (TBAHS), cetyltrimethylammonium bromide (CTMAB) and tricaprylmethylammonium chloride (TCMC). The reaction was carried out by simple magnetic stirring for about 2 h at 60 ºC. The products were recrystallized and analyzed by infrared and UV-visible spectral techniques. Benzaldehyde and substituted benzaldehydes were formed in good yield (> 90%) on oxidation of benzyl chlorides and benzyl bromides. The reaction is proved to be highly selective due to the absence of acids or any other products during the reaction. All the phase transfer catalysts were highly effective in bringing out the reaction in both the solvents. This is highly significant as the oxidation reaction will not occur in non-polar solvents without the presence of phase transfer catalysts.
Aspectos metodológicos e de utilização do fator de impacto
Authors: Almeida Catia Cândida , Gracio Maria Cláudia Cabrini
Published: September 2020

A presente pesquisa objetiva identificar os aspectos metodológicos e de utilização do Fator de Impacto, os quais são alvo de críticas e de questionamentos por parte dos pesquisadores. Como procedimento metodológico, realizou-se um levantamento bibliográfico, a partir da base de dados Web of Science, sendo identificado nove artigos nos períodos de 1995 a 2018. Como resultado, observou-se que as críticas apontadas relacionam-se à composição dos periódicos na base de dados Web of Science, que não é padronizada em termos de classificação dos tipos de documentos; à representatividade das áreas científicas e à abrangência regional. Ainda, a diferença na distribuição das citações entre as áreas, sem a devida normalização para a comparação entre elas, configurou importante crítica ao uso do Fator de Impacto. Considerando a contemporaneidade dos resultados obtidos, conclui-se que problemas metodológicos e de uso do Fator de Impacto ainda constituem problemas atuais nas publicações científicas que embasam seus resultados neste indicador.
Low Pepsinogen I/II Ratio and High Gastrin-17 Levels Typify Chronic Atrophic Autoimmune Gastritis Patients With Gastric Neuroendocrine Tumors
Authors: Magris Raffaella , De Re Valli , Maiero Stefania , Fornasarig Mara , Guarnieri Giovanni , Caggiari Laura , Mazzon Cinzia , Zanette Giorgio , Steffan Agostino , Canzonieri Vincenzo , Cannizzaro Renato
Published: September 2020

INTRODUCTION:

Chronic atrophic autoimmune gastritis (CAAG) can lead to the development of gastric neuroendocrine tumors (gNETs) and can be accompanied by other autoimmune diseases. This study aimed to determine, in CAAG patients, the association of gNET development, the prevalence of autoimmune diseases other than CAAG, the association of autoimmunity, and gNET development with pepsinogen I, II, gastrin-17, and Helicobacter pylori infection analysis.

METHODS:

We determined the prevalence of gNETs and other autoimmune diseases and analyzed pepsinogen I and II, gastrin-17 serum levels, and H. pylori infection in all patients diagnosed with CAAG at our hospital between 2013 and 2017.

RESULTS:

A total of 156 patients were studied and in 15.4% was observed concomitant gNET. Approximately 68.6% had at least 1 other autoimmune disease at diagnosis of CAAG. Approximately 60.9% had autoimmune thyroiditis, followed by diabetes (19.9%) and autoimmune polyendocrine syndrome (12.8%). CAAG patients with and without gNET had similar rates of comorbidity with other autoimmune diseases, but the pepsinogen I/II ratio was lower in patients with gNET (1.6 vs 4.5, P = 0.018). Receiver operating characteristic curve analyses identified a pepsinogen I/II ratio <2.3 and gastrin-17 levels >29.6 pmol/L as cutoffs distinguishing CAAG patients with gNET from those without. The combined use of these cutoff correctly identified 16 of the 18 CAAG patients with gNET (P = 0.007). H. pylori infection was observed in 28.7% of cases tested but did not associate with gNET.

DISCUSSION:

This study suggests that a low pepsinogen I/II ratio and high gastrin-17 levels characterize patients with CAAG and gNET and confirms the frequent coexistence of CAAG with other autoimmune diseases.
Análise do grau de especialização da produção de cana-de-açúcar nos municípios goianos (2005 - 2015)
Authors: Faria de Queiroz Sabrina , Silva de Godoi Matheus , De Queiroz Antônio Marcos , Rosal Carvalho Cláudia Regina
Published: September 2020

O presente estudo analisa o grau de especialização e a concentração na produção de cana-de-açúcar dos municípios goianos, nos anos de 2005 e 2015 através do cálculo do quociente locacional (QL). Os resultados indicaram a manutenção de uma estrutura produtiva concentrada, em termos da produção de cana-de-açúcar, nas regiões mais centrais e desenvolvidas do estado de Goiás devido à crescente especialização daquela produção nos municípios das mesorregiões Sul goiano e Centro goiano, tradicionalmente mais dinâmicas economicamente. Esse efeito está associado, principalmente, aos incentivos fiscais oriundos do governo federal e estadual, melhores condições de infraestrutura daquelas mesorregiões, zoneamento agroecológico da cana e disponibilidade de mão de obra e de terras.
Os Desafios Socioeconômicos da Agricultura Familiar: Um estudo para o Assentamento Primavera em Rondonópolis
Authors: Correa da Cruz Andreza , Heck Cláudia Regina , Fagundes Carrara Aniela
Published: September 2020

A expansão dos assentamentos rurais como política agrária no país representou (e ainda representa) a forma para resolução dos conflitos no campo, sem alterar a estrutura fundiária e modificar a estrutura de poder no campo. O artigo propõe-se a compreender as relações socioeconômicas vivenciadas no Assentamento Primavera, localizado no município de Rondonópolis, no Mato Grosso, e como as atividades desenvolvidas pelos agricultores familiares, possibilitam a sua permanência na propriedade. A metodologia adotada na pesquisa compreende a análise bibliográfica e documental, além da aplicação de questionário estruturado as famílias assentadas. Foi detectado que, apesar da geração de renda e das condições de produção no assentamento, a distância do centro urbano e a falta de serviços de assistência social, estão se tornando empecilhos para a sucessão familiar e a permanência das famílias no campo. Adicionalmente, a expansão da produção de commodities tem valorizado as terras do assentamento, tornando-se um atrativo para a migração do campo para a cidade.
Reseña / Los caminos de la extensión en América Latina y el Caribe
Authors: García González Ernesto
Published: September 2020

“Interpretar la extensión universitaria como un proceso educativo en donde todas las personas pueden aprender y enseñar” (Declaratoria del XIV Congreso Latinoamericano de Extensión Universitaria, 2017, p. 2) es un reto de la educación superior y ello impulsa al autor de esta reseña al intento de aportar al estudio de la extensión universitaria para entender las relaciones que se establecen entre los sujetos que participan en la universidad de estos tiempos.Se trata de invitar a la lectura para descubrir los vínculos entre los que son protagonistas de lo que expone el libro en la diversidad contextual. El autor agradece por anticipado si se logra que los profesores lean y aprendan para su práctica pedagógica en tanto espacio de relación entre sujetos que enseñan y aprenden en los recintos universitarios.
Trinity, Subordination, and Heresy: A Reply to Mark Edwards
Authors: Mullins Ryan T.
Published: September 2020

In this article, I offer some analytic reflections on Mark Edward's paper, "Is Subordinationism a Heresy?" I shall discuss the desiderata for a conciliar Trinitarian theology, the divine essence, and the different notions of subordination that Edwards identifies. Then I shall consider two arguments that certain accepted, conciliar notions of subordination lead to heretical notions of subordination. Thus raising the worry that conciliar Trinitarian theology might involve some internal incoherence between the homoousios doctrine and the subordination of the Son and Holy Spirit to the Father.
Kolik času zameškají žáci v českém základním školství?
Authors: Skalová Eva , Dvořák Dominik
Published: September 2020

Cíle. Absence žáků ve škole je závažným jevem s dopadem na žáka i školu. V českém školství dosud převládaly prakticky orientované přístupy zaměřené na řešení případů častých neomluvených absencí – záškoláctví. V zahraničních vzdělávacích systémech roste pozornost, která je věnována sledování, předcházení nebo zmírňování dopadů zvýšené celkové absence žáků bez ohledu na její příčiny. Náš článek si proto klade dva cíle: zaprvé ukazujeme, jak se vymezuje v zahraničí tzv. chronická absence, zadruhé hledáme odhad průměrné celkové absence v českých základních školách.Metody. Provedli jsme explorativní analýzu otevřených dat z činnosti České školní inspekce (záznamy o 11 625 hospitovaných hodinách) a pilotních mikrodat z velké základní školy (N = 957 žáků).Výsledky. Naše analýza naznačuje, že jak průměrná celková absence (12 % na prvním stupni a 13 % na druhém stupni základních škol), tak chronická absence – podíl žáků s velkými počty zameškaných hodin – by mohly v Česku být poměrně vysoké. Závěry. Téma by mělo být dále podrobněji sledováno jak výzkumníky, tak tvůrci vzdělávací politiky. Při tom je třeba pracovat s více různými indikátory než s dosud převažujícím vykazováním absolutního počtu zameškaných hodin.
Contexts of empirical research in the social sciences
Authors: Brzeziński Jerzy Marian
Published: September 2020

The article analyses “immersing” empirical research conducted in the field of social sciences (psychology, sociology, education etc.) in four contexts: psychological, ethical, cultural and the context of methodological awareness. It focuses in particular on the following issues, crucial for the condition of social sciences:– research competences of those who undertake to design and conduct empirical research (the state of social and individual methodological awareness);– specificity of psychological research carried out with the participation of human subjects – the perception of empirical research as an interaction “researcher – participant of the study”;– cultural specificity of the environment in which research takes place;– attitude of researchers towards research participants (the state of ethical awareness);– accepted patterns of disseminating research results (the policy of editors of scientific journals to approve only of such papers which contain statistically significant results i.e. with significance at the level of p < 0,05;;– assessment practices applied in institutions employing researchers: bibliometric assessment of academic units and the evaluation of individual scholars’ research performance;– succumbing to the pressure exerted by supervisors on researchers to publish “at all costs.”
Towards scalable dataframe systems
Authors: Petersohn Devin , Macke Stephen , Xin Doris , Ma William , Lee Doris , Mo Xiangxi , Gonzalez Joseph E. , Hellerstein Joseph M. , Joseph Anthony D. , Parameswaran Aditya
Published: September 2020

Dataframes are a popular abstraction to represent, prepare, and analyze data. Despite the remarkable success of dataframe libraries in R and Python, dataframes face performance issues even on moderately large datasets. Moreover, there is significant ambiguity regarding dataframe semantics. In this paper we lay out a vision and roadmap for scalable dataframe systems. To demonstrate the potential in this area, we report on our experience building Modin, a scaled-up implementation of the most widely-used and complex dataframe API today, Python's pandas. With pandas as a reference, we propose a simple data model and algebra for dataframes to ground discussion in the field. Given this foundation, we lay out an agenda of open research opportunities where the distinct features of dataframes will require extending the state of the art in many dimensions of data management. We discuss the implications of signature dataframe features including flexible schemas, ordering, row/column equivalence, and data/metadata fluidity, as well as the piecemeal, trial-and-error-based approach to interacting with dataframes.
Privacy preserving vertical federated learning for tree-based models
Authors: Wu Yuncheng , Cai Shaofeng , Xiao Xiaokui , Chen Gang , Ooi Beng Chin
Published: September 2020

Federated learning (FL) is an emerging paradigm that enables multiple organizations to jointly train a model without revealing their private data to each other. This paper studies
vertical
federated learning, which tackles the scenarios where (i) collaborating organizations own data of the same set of users but with disjoint features, and (ii) only one organization holds the labels. We propose Pivot, a novel solution for privacy preserving vertical decision tree training and prediction, ensuring that no intermediate information is disclosed other than those the clients have agreed to release (i.e., the final tree model and the prediction output). Pivot does not rely on any trusted third party and provides protection against a semi-honest adversary that may compromise
m
- 1 out of
m
clients. We further identify two privacy leakages when the trained decision tree model is released in plain-text and propose an enhanced protocol to mitigate them. The proposed solution can also be extended to tree ensemble models, e.g., random forest (RF) and gradient boosting decision tree (GBDT) by treating single decision trees as building blocks. Theoretical and experimental analysis suggest that Pivot is efficient for the privacy achieved.
Efficient and effective similar subtrajectory search with deep reinforcement learning
Authors: Wang Zheng , Long Cheng , Cong Gao , Liu Yiding
Published: September 2020

Similar trajectory search is a fundamental problem and has been well studied over the past two decades. However, the similar subtrajectory search (SimSub) problem, aiming to return a portion of a trajectory (i.e., a subtrajectory), which is the most similar to a query trajectory, has been mostly disregarded despite that it could capture trajectory similarity in a finer-grained way and many applications take subtrajectories as basic units for analysis. In this paper, we study the SimSub problem and develop a suite of algorithms including both exact and approximate ones. Among those approximate algorithms, two that are based on deep reinforcement learning stand out and outperform those non-learning based algorithms in terms of effectiveness and efficiency. We conduct experiments on real-world trajectory datasets, which verify the effectiveness and efficiency of the proposed algorithms.
Distributed subgraph counting
Authors: Zhang Hao , Yu Jeffrey Xu , Zhang Yikai , Zhao Kangfei , Cheng Hong
Published: September 2020

In this paper, we study local subgraph counting, which is to count the occurrences of a user-given pattern graph
p
around every node
v
in a data graph
G
, when
v
matches to a given orbit
o
in
p
, where the orbit serves as a center to count
p.
In general, the orbit can be a node, an edge, or a set of nodes in
p.
Local subgraph counting has played an important role in characterizing high-order local structures that exhibit in a large graph, and has been widely used in denser and relevant communities mining, graphlet degree distribution, discriminative features selection for link prediction, relational classification and recommendation. In the literature, almost all the existing works support a
k
-node pattern graph, for
k
≤ 5, with either 1 node orbit or 1 edge orbit. Their approaches are difficult to support larger
k
due to the fact that subgraph counting is to count by subgraph isomorphism. In this work, we develop a new general approach to count any
k
pattern graphs with any orbits selected. The key idea behind is that we do local subgraph counting by homomorphism counting, which can be solved by relational algebra using joins, group-by and aggregation. By homomorphism counting, we do local subgraph counting by eliminating counts for those that are not subgraph isomorphism matchings from the total count for any possible matchings. We have developed a distributed system named DISC on
Spark.
Our extensive experiments validate the efficiency of our approach by testing 114 local subgraph counting queries used in the existing work over real graphs, where no existing work can support all.
uTree
Authors: Chen Youmin , Lu Youyou , Fang Kedong , Wang Qing , Shu Jiwu
Published: September 2020

Tail latency is a critical design issue in recent storage systems. B
+
-tree, as a fundamental building block in storage systems, incurs high tail latency, especially when placed in persistent memory (PM). Our empirical study specifies two factors that lead to such latency spikes: (
i
) the internal structural refinement operations (i.e., split, merge, and balance), and (
ii
) the interference between concurrent operations. The problem is even worse when high concurrency meets with the low write bandwidth of persistent memory.

In this paper, we propose a B
+
-tree variant named μTree. It incorporates a shadow list-based layer to the leaf nodes of a B
+
-tree to gain benefits from both list and tree data structures. The list layer in PM is exempt from the structural refinement operations since list nodes in the list layer own separate PM spaces, which are organized in an
element-based
way. Meanwhile, μTree still gains the locality benefit from the tree-based nodes. To alleviate the interference overhead, μTree coordinates the concurrency control between the tree and list layer, which moves the slow PM accesses out of the critical path. We compare μTree to state-of-the-art designs of PM-aware B
+
-tree indices under both YCSB workload and real-world applications. μTree achieves a 99th percentile latency that is one order of magnitude lower and 2.8 - 4.7 times higher throughput.
IsoDiff
Authors: Gan Yifan , Ren Xueyuan , Ripberger Drew , Blanas Spyros , Wang Yang
Published: September 2020

Weak isolation levels, such as Read Committed and Snapshot Isolation, are widely used by databases for their higher concurrency, but may introduce subtle correctness errors in applications that only experts can identify.

This paper proposes IsoDiff, a tool to help a developer debug the anomalies caused by weak isolation for an application. To address the challenge that the number of anomalies can be non-polynomial with respect to the number of types of transactions, IsoDiff finds a representative subset of anomalies involving different transactions, operations, and problematic patterns. To reduce false positives, IsoDiff proposes two novel methods (correlation detection and timing relationship check) to eliminate as many false positives as possible and further provides a mechanism to incorporate the developer's feedback to eliminate the remaining ones.

The evaluation of IsoDiff on TPC-C and seven real applications under Snapshot Isolation and Read Committed isolation shows that IsoDiff can balance computation time and the coverage of anomalies; it can automatically eliminate a significant portion of false positives; and its feedback mechanism allows a developer to express the root cause of false positives, which can eliminate many false positives with only a small number of developer hints.
Suffix rank
Authors: Barsky Marina , Gabor Jonathan , Consens Mariano P. , Thomo Alex
Published: September 2020

We investigate the problem of building a suffix array substring index for inputs significantly larger than main memory. This problem is especially important in the context of biological sequence analysis, where biological polymers can be thought of as very large contiguous strings. The objective is to index every substring of these long strings to facilitate efficient queries. We propose a new simple, scalable, and inherently parallelizable algorithm for building a suffix array for out-of-core strings. Our new algorithm,
Suffix Rank
, scales to arbitrarily large inputs, using disk as a memory extension. It solves the problem in just
O
(log
n
) scans over the disk-resident data. We evaluate the practical performance of our new algorithm, and show that for inputs significantly larger than the available amount of RAM, it scales better than other state-of-the-art solutions, such as
eSAIS, SAscan
, and
eGSA.
Apache IoTDB
Authors: Wang Chen , Huang Xiangdong , Qiao Jialin , Jiang Tian , Rui Lei , Zhang Jinrui , Kang Rong , Feinauer Julian , McGrail Kevin A. , Wang Peng , Luo Diaohan , Yuan Jun , Wang Jianmin , Sun Jiaguang
Published: September 2020

The amount of time-series data that is generated has exploded due to the growing popularity of Internet of Things (IoT) devices and applications. These applications require efficient management of the time-series data on both the edge and cloud side that support high throughput ingestion, low latency query and advanced time series analysis. In this demonstration, we present Apache IoTDB managing time-series data to enable new classes of IoT applications. IoTDB has both edge and cloud versions, provides an optimized columnar file format for efficient time-series data storage, and time-series database with high ingestion rate, low latency queries and data analysis support. It is specially optimized for time-series oriented operations like aggregations query, down-sampling and sub-sequence similarity search. An edge-to-cloud time-series data management application is chosen to demonstrate how IoTDB handles time-series data in real-time and supports advanced analytics by integrating with Hadoop and Spark. An end-to-end IoT data management solution is shown by integrating IoTDB with PLC4x, Calcite, and Grafana.
CrocodileDB in action
Authors: Tang Dixin , Shang Zechao , Elmore Aaron J. , Krishnan Sanjay , Franklin Michael J.
Published: September 2020

Existing stream processing and continuous query processing systems eagerly maintain standing queries by consuming all available resources to finish the jobs at hand, which can be a major source of wasting CPU cycles and memory resources. However, users sometimes do not need to see the up-to-date query result right after the data is ready, and thus allow a slackness of time before the result is returned, which provides new opportunities to avoid wasting resources. We proposed CrocodileDB, a resource-efficient database, where users specify a performance goal representing the maximally allowed slackness of time and the system generates a query plan to minimize resource consumption (e.g. memory consumption or CPU cycles) while meeting this performance goal at the same time. In this paper, we demonstrate how users interact with CrocodileDB and show how the time slackness enables our optimization of reducing CPU consumption: Incrementability-aware Query Processing (InQP). With the slackness specified by users, InQP can reduce computing resource waste by selectively deferring the execution of parts of a query that are not amenable to incremental executions (i.e. outputting tuples that can be deleted by later executions in a high probability). In this demonstration, users can set the performance goal as a trade-off between CPU consumption and query latency, and observe the CPU usages and other statistics to understand how InQP reduces computing resources.
LMFAO: An engine for batches of group-by aggregates
Authors: Schleich Maximilian , Olteanu Dan
Published: September 2020

LMFAO is an in-memory optimization and execution engine for large batches of group-by aggregates over joins. Such database workloads capture the data-intensive computation of a variety of data science applications.

We demonstrate LMFAO for three popular models: ridge linear regression with batch gradient descent, decision trees with CART, and clustering with Rk-means.
HDAG-explorer
Authors: Zhu Xuliang , Huang Xin , Huang Jinbin , Choi Byron , Xu Jianliang
Published: September 2020

Hierarchical directed acyclic graph (HDAG) is an essential graph model to represent terminology relationships in a hierarchy, such as Disease Ontology, Gene Ontology, and Wikipedia. However, due to massive terminologies and complex structures in a HDAG, an end user might feel difficult to explore and summarize the whole graph, which is practically useful but less studied in the literature. In this demo, we develop an interactive system of HDAG-Explorer to help users summarize HDAG with highly important and diverse vertices. Our HDAG-Explorer system exhibits several useful features including summarized visualization, interactive exploration, and structural statistics report. All these features facilitate in-depth understanding of the HDAG data. We showcase the usability of the HDAG-Explorer through two real-world applications of summarized topic recommendation and visual data exploration.
I-Rex
Authors: Miao Zhengjie , Chen Tiangang , Bendeck lexander , Day Kevin , Roy Sudeepa , Yang Jun
Published: September 2020

We demonstrate I-Rex
1
, a system designed to help users understand SQL query evaluation and debug SQL queries. I-Rex lets users interactively "trace" the evaluation of complex SQL queries, including those with correlated subqueries. I-Rex also explains why a query returns an incorrect answer with respect to a reference query over a test database instance---a common use case in education and software regression testing. To avoid the cognitive overload caused by debugging over a large database instance, I-Rex lets users focus on smaller instances contained in the large one (which we call "counterexamples") that still distinguish the two queries. Supporting these features for SQL queries poses two key challenges. First, unlike debugging for procedural languages, it is not clear how to trace a declarative SQL query, because its execution plan often differs from how it was originally written. I-Rex offers a novel interface for tracing SQL query evaluation in a way faithful to how queries are written syntactically, even for complex queries involving multiple levels of nesting and correlation. Second, we need a method for finding small counterexamples that handles the complexity of practical SQL. I-Rex extends provenance support for SQL in non-trivial ways to work with various query constructs. This demonstration walks through use cases in which I-Rex helps users understand and debug SQL queries.
Industrial-strength OLTP using main memory and many cores
Authors: Avni Hillel , Aliev Alisher , Amor Oren , Avitzur Aharon , Bronshtein Ilan , Ginot Eli , Goikhman Shay , Levy Eliezer , Levy Idan , Lu Fuyang , Mishali Liran , Mo Yeqin , Pachter Nir , Sivov Dima , Veeraraghavan Vinoth , Vexler Vladi , Wang Lei , Wang Peng
Published: September 2020

GaussDB, and its open source version named openGauss, are Huawei's relational database management systems (RDBMS), featuring a primary disk-based storage engine. This paper presents a new storage engine for GaussDB that is optimized for main memory and many cores. We started from a research prototype which exploits the power of the hardware but is not useful for customers. This paper describes the details of turning this prototype to an industrial storage engine, including integration with GaussDB. Standard benchmarks show that the new engine provides more than 2.5x performance improvement to GaussDB for full TPC-C on Intel's x86 many-cores servers, as well as on Huawei TaiShan servers powered by ARM64-based Kunpeng CPUs.
LedgerDB
Authors: Yang Xinying , Zhang Yuan , Wang Sheng , Yu Benquan , Li Feifei , Li Yize , Yan Wenyuan
Published: September 2020

The emergence of Blockchain has attracted widespread attention. However, we observe that in practice, many applications on permissioned blockchains do not benefit from the decentralized architecture. When decentralized architecture is used but not required, system performance is often restricted, resulting in low throughput, high latency, and significant storage overhead. Hence, we propose LedgerDB on Alibaba Cloud, which is a centralized ledger database with tamper-evidence and non-repudiation features similar to blockchain, and provides strong auditability. LedgerDB has much higher throughput compared to blockchains. It offers stronger auditability by adopting a TSA two-way peg protocol, which prevents malicious behaviors from both users and service providers. LedgerDB supports verifiable data removals demanded by many real-world applications, which are able to remove obsolete records for storage saving and hide records for regulatory purpose, without compromising its verifiability. Experimental evaluation shows that LedgerDB's throughput is 80X higher than state-of-the-art permissioned blockchain (i.e., Hyperledger Fabric). Many blockchain customers (e.g., IP protection and supply chain) on Alibaba Cloud have switched to LedgerDB for its high throughput, low latency, strong auditability, and ease of use.
Magnet
Authors: Shen Min , Zhou Ye , Singh Chandni
Published: September 2020

Over the past decade, Apache Spark has become a popular compute engine for large scale data processing. Similar to other compute engines based on the MapReduce compute paradigm, the shuffle operation, namely the all-to-all transfer of the intermediate data, plays an important role in Spark. At LinkedIn, with the rapid growth of the data size and scale of the Spark deployment, the shuffle operation is becoming a bottleneck of further scaling the infrastructure. This has led to overall job slowness and even failures for long running jobs. This not only impacts developer productivity for addressing such slowness and failures, but also results in high operational cost of infrastructure.

In this work, we describe the main bottlenecks impacting shuffle scalability. We propose Magnet, a novel shuffle mechanism that can scale to handle petabytes of daily shuffled data and clusters with thousands of nodes. Magnet is designed to work with both on-prem and cloud-based cluster deployments. It addresses a key shuffle scalability bottleneck by merging fragmented intermediate shuffle data into large blocks. Magnet provides further improvements by co-locating merged blocks with the reduce tasks. Our benchmarks show that Magnet significantly improves shuffle performance independent of the underlying hardware. Magnet reduces the end-to-end runtime of Linkedln's production Spark jobs by nearly 30%. Furthermore, Magnet improves user productivity by removing the shuffle related tuning burden from users.
„Byzantinisch“ oder „germanisch“? Zur Ambivalenz wilhelminischer Mosaiken am Beispiel der Erlöserkirche in Bad Homburg
Authors: Niewöhner Philipp
Published: September 2020

The Erlöserkirche at Bad Homburg was built between 1903 and 1908 at the instigation of Kaiser Wilhelm II. It combines a neo-Romanesque exterior with Norman-Sicilian mosaics inside. Both were „Germanic“ to the emperor, and the church embodied his all encompassing claim to the tradition of the medieval Holy Roman Empire of the German Nation. Alternatively, the contemporary Byzantinist Ernst Gerland pointed to a Byzantine origin of the Norman-Sicilian models (and thus subtly contradicted the „pan-Germanic“ myth). This „Byzantine“ reading has prevailed ever since, but does not stand up to scrutiny. It only serves to obscure the „pan-Germanic“ concept of the church. This contribution restores the „Germanic“ understanding and makes the point that the latter must be acknowledged in order to make proper sense of the church’s art and architecture, but also in order to face (rather than to downplay and conveniently forget) the racist-chauvinist character of German imperialism.
Hydrogen Production from Catalytic Polyethylene Terephthalate Waste Reforming Reaction, an overview
Authors: Nabgan Walid , Nabgan Bahador , Abdullah Tuan Amran Tuan , Ngadi Norzita , Jalil Aishah Abdul , Nordin Abu Hassan , Latif Nur Aien Fatini Abd , Othman Noor Fathiah Haziqah
Published: September 2020

As a sustainable and renewable energy carrier for transition, hydrogen is considered as a key future fuel for the low carbon energy systems. During the past few decades, attention has been given to the conversion of waste materials, including plastics to the production of hydrogen. Studies in this field are of great importance because they resolve numerous problems brought about by plastic waste with other forms of waste. Polyethylene terephthalate (PET) is one of the major products of plastic waste which constitutes a major threat to environmental conservation efforts and harms living organism. Phenol has been chosen in this study as a solvent for PET to produce hydrogen because of unwanted liquid product in the bio-oil. This research investigates catalytic steam reforming of phenol with dissolved PET for hydrogen production. The aim of this study was the review of a highly active and stable catalyst for hydrogen production from steam reforming waste products. The analysis of product composition indicated that steam reforming of PET-phenol generally produced a high amount of aliphatic branched-chain compounds, together with a moderate amount of cyclic compounds. The reaction conditions also led to the alkylation of phenol by the reforming products from the PET-phenol solution with and without the catalyst. In conclusion, this study explored new ways to use l product derived from waste plastic materials. It provides a promising clean technology, which employed polyethylene terephthalate waste dissolved in phenol (as a solvent) for hydrogen production.
Hashtags, Tweets, Protest? Varianten des digitalen Aktivismus
Authors: Fielitz Maik , Staemmler Daniel
Published: September 2020

Mit der Digitalisierung entstehen Ausdrucks- und Organisationsformen von Protest, die das Verständnis von politischer Mobilisierung herausfordern. Über Instant-Messaging, soziale Medien und alternative Plattformen bildet sich ein Eigenleben des digitalen Aktivismus heraus, das auch das Protestgeschehen auf der Straße beeinflusst. In der Sozialen Bewegungsforschung lösten die Ausdifferenzierung des digitalen Aktivismus und die komplexen Interaktionen zwischen Online- und Offlineprotest neue Debatten aus. Dieser Beitrag schlägt eine Systematisierung des Wissens zu digitalem Aktivismus vor, indem aus den Medienpraktiken der Aktivist*innen fünf Varianten vorgestellt und im Kontext jener digitalen Infrastrukturen diskutiert werden, auf die sie zurückgreifen.
Green preparation of lignin nanoparticles in an aqueous hydrotropic solution and application in biobased nanocomposite films
Authors: Yang Mingyan , Zhang Xiao , Guan Shuyi , Dou Yan , Gao Xiaofeng , Miao Linping
Published: September 2020

Lignin nanoparticles (LNPs) from lignocellulosic biomass are expected to become promising basic building blocks for various applications in the development of multifunctional nanocomposites. Facile green preparation of LNPs and their application in polyvinyl alcohol (PVA) composite films were studied in this paper. LNPs were produced by performing fractionation of wheat straws at less than 80 °C with a recyclable hydrotropic, aqueous p-toluene sulfonic acid (p-TsOH). The dissolved lignin could be simply separated as LNPs by diluting the spent liquor (SL) to below the minimal hydrotropic concentration (MHC) of 11.5%. The resulting LPNs exhibited an oblate spheroid morphology and a uniform particle size distribution. After introducing the available LNPs into the PVA matrix at 6% loading, the nanocomposite products could block 100 and 95% of UV light at 315 and 400 nm, respectively, and exhibited 80% antioxidant activity. In addition, the respective maximum TS and TM were 59.7 MPa and 2.07 GPa, respectively, which were increases of approximately 36 and 104% compared with those of pure PVA film. The LNPs/PVA nanocomposite films displayed improved UV resistance, mechanical properties, thermal stability and antioxidant activity and could be used as additional multifunctional agents in the fields of biodegradable plastics, tissue engineering and UV-protective biobased materials.
Racialization and gender in Tumblr: Beyoncé as a raciolinguistic semiotic resource
Authors: China Addie Sayers
Published: September 2020

Combining raciolinguistics and social semiotics, I explore a snapshot of socio-politically and historically contextualized multimodal digital activity in social networking site Tumblr involving American entertainer Beyoncé. I examine a set of 41 Tumblr posts, gathered in 2016 during Beyoncé’s heightened social and political salience, in which users expressed counterhegemonic stances. I first demonstrate how Tumblr users employ images and references of Beyoncé in ways that resist visual and linguistic hegemonic discourses and realize and index issues of race and gender. I show how Tumblr users resemiotize and reentextualize Beyoncé in decolonizing stances, including those that challenge White gazes, prioritize non-White subjectivity, and destabilize Whiteness. I conclude that Beyoncé’s use as a semiotic resource adds to her indexicalities as she is deployed in various stances. I assert that a raciolinguistic perspective elucidates intersectionally racialized and gendered ideological changes to Beyoncé’s multimodal indexical field and that attention to digital semiotics increases the multimodal and intersectional perspectives of raciolinguistic analyses.
Efficacy and safety of endovascular treatment for patients with acute intracranial atherosclerosis–related posterior circulation stroke: a systematic review and meta-analysis
Authors: Bao Jiajia , Hong Ye , Cui Chaohua , Ma Mengmeng , Gao Lijie , Liu Qian , Chen Ning , He Li
Published: September 2020

The benefit of endovascular treatment (EVT) for patients with intracranial atherosclerosis–related large vessel occlusion (ICAS-LVO) in posterior circulation stroke (PCS) is inconsistent. This systematic review and meta-analysis were conducted to estimate the effect of ICAS-LVO in PCS treated by EVT. A systematic review was completed, tracking studies from their date of inception until February 2020. Clinical studies which compared outcomes after EVT for ICAS-LVO and non–ICAS-LVO in PCS were included. Data were synthesized and interpreted from meta-analysis. A total of 688 patients (352 ICAS-LVO and 336 non–ICAS-LVO) in the eight studies were included. The successful reperfusion rate (odds ratio [OR], 0.58; 95% confidence intervals [95% CIs], 0.37–0.93; P = 0.02) was lower in PCS with ICAS-LVO than non–ICAS-LVO. And for other clinical outcomes, there were no differences between both groups. Moreover, there were no statistical differences of any clinical outcome among subgroups stratified by nations and target vessel occlusion location. With respect to patients’ characteristics, age (mean difference [MD], −2.75; 95% CI, −4.62–−0.88; P = 0.004), pc-Alberta Stroke Program Early CT Score (MD, −0.49; 95% CI, −0.94–−0.05; P = 0.03), distributions of sex (male) (OR, 2.34; 95% CI, 1.53–3.56; P < 0.001), prior or current smoking (OR, 1.85; 95% CI, 1.12–3.07; P = 0.02), hypertension (OR, 2.06; 95% CI, 1.32–3.22; P = 0.002), coronary artery disease (OR, 0.27; 95% CI, 0.11–0.66; P = 0.004) and general anesthesia (OR, 2.89; 95% CI, 1.54–5.45; P = 0.001) were statistically different between both groups. In conclusion, more targeted assessments are warranted for patients with ICAS-LVO–related PCS during clinical strategies, and the benefit of EVT for PCS with ICAS-LVO deserves further research.
Trennung radioaktiver Yttererden in einer Adsorptionssäule (Radiometrische Adsorptionsanalyse)
Authors: Lindner Roland , Peter Otto
Published: September 2020

Abstrakt

Die Methode der radiometrischen Adsorptionsanalyse (chromatographische Adsorption unter Verwendung radioaktiver Atomarten) wird auf die Yttererden und das chemisch dazugehörige Yttrium angewendet. Hierbei ergeben sich den bisherigen Verfahren überlegene Trennungen dieser Elemente, welche - durch Neutronenbestrahlung radioaktiv indiziert - bequem quantitativ bestimmt werden können.
Ergebnisse der Tieftemperaturforschung
Authors: Clusius Klaus
Published: September 2020

Abstrakt

Die Molwärme des Lithiumfluorids wurde zwischen 18° und 273,2° abs nach der Methode des Vacuumcalorimeters gemessen. Es zeigt sich im Sinne der von Blackman ausgeführten Rechnungen, daß die Debyesche Kontinuumstheorie nur qualitativ gültig ist, da eine einzige charakteristische Temperatur ΘD zur genauen Beschreibung des Verlaufs der Molwärme nicht ausreicht. Die ΘD l-Werte durchlaufen bei 80° abs ein Minimum von 607° und steigen einerseits auf 648° bei 0° Cel, andererseits nach tiefen Temperaturen auf 752° bei 18° abs an. Dabei sinkt die durchschnittliche Atomwärme, die bei LiF mit der halben Molwärme identisch ist, auf 0,0065 cal/g-Atom. Das ist etwa der tausendste Teil des Wertes bei Zimmertemperatur, ohne daß das eigentliche Gebiet des Debyeschen T3-Gesetzes erreicht wäre. Lithiumfluorid ist bei weitem das geeignetste Versuchsmaterial, um die Anwendbarkeit der Bornschen Gittertheorie auf die Molwärme der Ionenkrystalle zu prüfen.
Frequenzanalyse bioelektrischer Potentialschwankungen
Authors: Franek Bruno
Published: September 2020

Mit der Frage nach dem Entstehungsort der gefilterten polyfrequenten bioelektrischen Potentialschwankungen wurde das Verhältnis einer jeden Frequenz zu allen anderen Frequenzen an den verschiedenen Ableitepunkten untersucht.- Die verschiedenen Kopfableitepunkte waren dabei so ausgesucht, daß sie sich etwa mitten über cytoarchitektonisch stark differierenden Feldern der Großhirnrinde befanden. Es wurden von einem prä- und einem postzentralen Punkte höherfrequente Hirnaktionsströme abgeleitet, die sich durch plötzlichen Beginn, synchronen und abklingenden Schwingungsverlauf sowie durch eine enorme Spannungsüberhöhung und klare ortsbedingte Differenzierung auszeichnen. Sie dürften den funktionellen Ausdruck der darunter befindlichen morphologischen Unterschiedlichkeit der Großhirnrinde darstellen. Der enkephalogene Charakter der höheren Frequenzen des passiven EEG wird sehr in Frage gestellt, da sich an vielen Stellen des Körpers die prinzipiell gleichen polyfrequenten Erscheinungen mit parallel verlaufender Spannungsverminderung und gewissen Beziehungen zum Blutkreislaufsystem nachweisen lassen. Dagegen wird durch Frequenzanalyse von dicht nebeneinander abgeleiteten Hirnaktionsströmen die bioelektrische Differenzierung der Großhirnrinde bestätigt
Über eine langperiodische Struktur der Cellulosemoleküle und der aus Cellulose aufgebauten Pflanzenfasern
Authors: Schulz G. V. , Husemann E.
Published: September 2020

Abstrakt

Cellulose aus Pflanzenfasern (Baumwolle, Ramie) besteht aus linearen Kettenmolekülen, welche etwa 3200 in ßglucosidischer Bindung verknüpfte Glucosereste enthalten. Fraktionierversuche an nativer Cellulose zeigen, daß deren Moleküle (ganz oder annähernd) gleiche Länge besitzen. Die Molekülgrößen in abgebauten Cellulosen sind sehr viel einheitlicher als zu erwarten wäre, wenn alle Bindungen in der Kette gleichartig wären. Eine genaue Untersuchung der Molekülgrößenverteilung ergibt, daß in regelmäßigen Abständen von etwa 500 Glucoseresten leichter aufspaltbare Bindungen in der Kette vorhanden sind. Zum gleichen Ergebnis führt eine reaktionskinetische Analyse der Abbauvorgänge. - Über mikroskopische Aufnahmen von nach einer neuen Methode präparierten Naturfasern zeigen, daß sich die Periodizität der Moleküle in eine Periodizität des Faseraufbaus fortsetzt. Künstliche Fasern besitzen diese Periodizität nicht. - Aus dem Befund ergeben sich Konsequenzen über die Entstehung der makromolekularen Stoffe im Organismus.
Über die Stabilitätsbedingung der Elektronenbewegung im Rheotron
Authors: Gans Richard
Published: September 2020

Abstrakt

Es werden die notwendigen Bedingungen für die Verteilung des Feldes im Rheotron angegeben [Gl. (12) und (13)], damit die Elektronenbewegung stabil ist. Diese Bedingungen beziehen sich nicht nur auf die unmittelbare Umgebung des Gleichgewichtskreises, sondern auf ein endliches Raumgebiet.
Das Vorkommen von Acetylcholin im Blut nach experimentellen Verbrennungen
Authors: Hoppe-Seylerf Felix-Adolf , Schümmelfeder Norbert
Published: September 2020

Oh sich im Blut nach lokalen Verbrennungen von Extremitäten, welche vorübergehend während dieser Schädigung aus dem Kreislauf ausgeschaltet waren, freies Acetylcholin (ACh) findet, und ob das Auftreten von ACh bzw. acetylcholinwirksamer Stoffe von ursächlicher Bedeutung für das Zustandekommen des Schocks nach solchen Schädigungen sein kann, wurde in Versuchen geprüft. Acetylcholin-Bestimmungen führten wir an Hunden, bei welchen Hautverbrennungen an Extremitäten gesetzt wurden, in Pernocton-Chloralose-Narkose aus, unter gleichzeitiger Registrierung des Blutdrucks. Die Extremitäten wurden während der Schädigung durch Anlegen einer Esmarch -' sehen Blutleere aus dem Kreislauf ausgeschaltet. Nach Lösen der Blutleere kam es zum Schock. Nach vorherigen Gaben von Atropin und Eserin wurde in eserinhaltiger Auffanglösung Blut aufgenommen und ACh im Vollblut bzw. Plasma ausgewertet. Weitere Blutproben wurden zur Auswertung nach dem von Kahlson entwickelten Verfahren enteiweißt und konzentriert. Alle Blut- bzw. Plasmaproben sowie die Konzentrate wurden am Blutegelpräparat nach M i n z ausgewertet. Sofort nach Anlage der Blutleere waren nur bei einem von sieben Hunden nachweisbare Mengen von Acetylcholin im Blut vorhanden. Während der Verbrennung bei noch bestehender Abschnürung fanden sich im Blut bei drei von sieben Tieren nachweisbare Mengen von ACh, in einem Fall bei noch unverändertem Blutdruck, bei zwei Tieren, während der Blutdruck bereits langsam abfiel. Nach Öffnung der Blutleere und Eintritt des Kollapses waren bei drei von sieben Tieren sicher nachweis- und auswertbare Mengen von ACh vorhanden, während bei zwei weiteren wahrscheinlich geringere, aber nicht mehr quantitativ auswertbare Mengen im Blut nachweisbar waren. Die gefundenen ACh-Mengen schwankten zwischen 1,25 und 15 y/l. Nach Einzelinjektionen und Dauerinfusionen von ACh-Uösungen wurden wesentlich größere ACh-Mengen im Blut gefunden (bis 60 y/l). Uang andauernde Infusionen mit Gaben bis zu 15 mg ACh in der Minute führten nicht zum tödlichen Kollaps. Bei faradischer Reizung der Halsvagi fanden wir ACh im Blut größenordnungsmäßig etwa in der gleichen Menge wie bei den Schockversuchen. Die Blutdrucksenkungen waren jedoch nach den Vagusreizungen wesentlich geringer. Das Auftreten von ACh im Blut bei unseren Versuchen wird daher als Folgeerscheinung und nicht als Ursache der Kreislaufveränderungen angesehen.
Veränderungen von Nachkommenziffer und Nachkommengröße sowie der Altersverteilung von Inseleidechsen
Authors: Kramer Gustav
Published: September 2020

Frischgeschlüpfte Inseleidechsen sind relativ (und meist auch absolut) größer als die Jungen der Festlandpopulationen, von denen die Inseltiere, abgeleitet werden müssen. Dafür ist die jährliche Nachkommenzahl der Festlandtiere wesentlich höher als die der Inseleidechsen. An Hand der Größenverteilung und mittels einer kombinierten Methode der Altersschätzung an erwachsenen Eidechsen wird nachgewiesen, daß die Altersverteilung bei Inseleidechsen wesentlich zugunsten höherer Altersstufen verschoben ist. Die gemeinsame Ursache für alle in dieser Untersuchung nachgewiesenen Verschiedenheiten wird erklärt, 1. durch Ausschluß der fressenden Feinde aus der Bilanz der Arterhaltung der Inseleidechsen; 2. durch Verschärfung der Daseinsbedingungen im Sommer, wodurch auch der Kannibalismus als spezieller Faktor in Wirkung gesetzt wird. Die letzte Gruppe von Faktoren begünstigt die Zunahme der Jungengröße; der erste Umstand läßt eine in diesem Sinne fortschreitende Umwandlung, die nur auf Kosten der Zahl der Nachkommen zu erreichen ist, zu; denn die Nachkommenziffer hat nach Wegfall der Feinde an arterhaltender Bedeutung eingebüßt.
Über ein quantenmechanisches Näherungsverfahren zur Behandlung der π-Elektronensysteme aromatischer Kohlenwasserstoffe II
Authors: Hartmann Hermann
Published: September 2020

Die Resultate des vorstehend 1 veröffentlichten Näherungsverfahrens zur quanten-mechanischen Berechnung der Energie des π-Elektronensystems aromatischer Kohlen-wasserstoffe werden mit denen des Hückel sehen Näherungsverfahrens verglichen. Bei den 18 Molekülen, die zum Vergleich herangezogen werden konnten, ergab sich sehr gute Übereinstimmung.