bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two seemingly paradoxical results in linear models: the variance inflation factor and the analysis of covariance
Authors: Ding Peng 
Published: March 2021

Abstract
A result from a standard linear model course is that the variance of the ordinary least squares (OLS) coefficient of a variable will never decrease when including additional covariates into the regression. The variance inflation factor (VIF) measures the increase of the variance. Another result from a standard linear model or experimental design course is that including additional covariates in a linear model of the outcome on the treatment indicator will never increase the variance of the OLS coefficient of the treatment at least asymptotically. This technique is called the analysis of covariance (ANCOVA), which is often used to improve the efficiency of treatment effect estimation. So we have two paradoxical results: adding covariates never decreases the variance in the first result but never increases the variance in the second result. In fact, these two results are derived under different assumptions. More precisely, the VIF result conditions on the treatment indicators but the ANCOVA result averages over them. Comparing the estimators with and without adjusting for additional covariates in a completely randomized experiment, I show that the former has smaller variance averaging over the treatment indicators, and the latter has smaller variance at the cost of a larger bias conditioning on the treatment indicators. Therefore, there is no real paradox.
Simulation-Based Neonatal Resuscitation Team Training: A Systematic Review
Authors: Lindhard Morten Søndergaard , Thim Signe , Laursen Henrik Sehested , Schram Anders Wester , Paltved Charlotte , Henriksen Tine Brink 
Published: March 2021

CONTEXT:
Several neonatal simulation-training programs have been deployed during the last decade, and in a growing number of studies, researchers have investigated the effects of simulation-based team training. This body of evidence remains to be compiled.

OBJECTIVE:
We performed a systematic review of the effects of simulation-based team training on clinical performance and patient outcome.

DATA SOURCES:
Medline, Embase, Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library.

STUDY SELECTION:
Two authors included studies of team training in critical neonatal situations with reported outcomes on clinical performance and patient outcome.

DATA EXTRACTION:
Two authors extracted data using a predefined template and assessed risk of bias using the Cochrane risk-of-bias tool 2.0 and the Newcastle-Ottawa quality assessment scale.

RESULTS:
We screened 1434 titles and abstracts, evaluated 173 full texts for eligibility, and included 24 studies. We identified only 2 studies with neonatal mortality outcomes, and no conclusion could be reached regarding the effects of simulation training in developed countries. Considering clinical performance, randomized studies revealed improved team performance in simulated re-evaluations 3 to 6 months after the intervention.

LIMITATIONS:
Meta-analysis was impossible because of heterogenous interventions and outcomes. Kirkpatrick’s model for evaluating training programs provided the framework for a narrative synthesis. Most included studies had significant methodologic limitations.

CONCLUSIONS:
Simulation-based team training in neonatal resuscitation improves team performance and technical performance in simulation-based evaluations 3 to 6 months later. The current evidence was insufficient to conclude on neonatal mortality after simulation-based team training because no studies were available from developed countries. In future work, researchers should include patient outcomes or clinical proxies of treatment quality whenever possible.
Structure forming and managing of properties of phosphorous cast irons for parts of internal combustion engine
Authors: Slynko G. , Slynko V. 
Published: March 2021

Purpose. Improving the mechanical and operational properties of details of internal combustion engines by managing the structure formation of phosphorous cast irons.
Research methods. Graphitized and bleached phosphorous cast irons with lamellar and globular graphite of laboratory and industrial melts, melted in electric induction furnaces with alloying modification and fractional casting into dry sand molds were investigated. Chemical composition, microstructure, physical and mechanical properties were determined using standard methods. Non-destructive quality control of engine parts, statistical analysis of experimental data and deterministic factor analysis of the influence of structural components on the properties of the cast irons were carried out according to the methods developed with the participation of the authors. Bench and road motor tests of optimal composition cast irons details were carried out in engines according to standard and factory methods in accordance with state standards.
Obtained results. The general laws and principles of the formation of the microstructure of cast irons with lamellar and nodular graphite are determined depending on the degree of their alloying with phosphorus and the influence of the scale factor. It has been established that phosphide eutectic in an amount of up to 5.8 % is a strengthening structural component and increases strength, hardness, wear resistance, heat resistance, and machin-ability of phosphorous cast irons with blade tools. The negative effect of phosphide eutectic on plastic properties and cyclic fracture toughness is less significant than the effect of increasing amounts of ferrite, its grain size and graphite. Optimal chemical compositions and microstructures of phosphorous cast irons for internal combustion engines details are recommended.
Scientific novelty. For the first time, a comprehensive system for managing the properties of phosphorous cast irons has been developed, including the analytical determination of the required characteristics of structural components and the technology for their production.
Practical value. Methods and technologies for melting, alloying, modifying, heat treatment and surface hardening of phosphorous cast irons have been developed. They make it possible to provide the required level of mechanical and operational properties of internal combustion engines details.
Mathematical simulation of welded deposit layers as for adaptation of materials to failure in quasidissipative tribosystems
Authors: Popov S. , Shumykin S. , Laptieva Н. 
Published: March 2021

Purpose. To establish mathematical models for the adaptation of materials under conditions of activation of a metastable structural-phase state of quasi-dissipative tribosystems. Determination and substantiation of factors for planning an active experiment due to which it is possible to create mathematical models of stable forecasts for increasing the wear resistance of materials.
Research methods. When conducting the experiments, a priori data were used in combination with our own scientific developments of mathematical models of the dependences of the influence of the chemical composition of alloys during manual and automatic electric arc surfacing on the physical and mechanical properties of the surface layer of the material, which is destroyed under tribosystem conditions. It was decided to use mathematical planning of research on the basis of an active experiment with the creation of models for the numerical description of the mathematical expectation in the form of regression equations.
Obtained results. On the basis of theoretical and practical scientific research with planning a passive and active experiment, a set of relevant knowledge has been obtained, which makes it possible to determine the main criterion requirements for the sensitivity of deposited steels and alloys to adaptation under the action of external mechanical and energy influences and allows to mathematically describe the characteristics of the alloy and provide a numeri­cal estimate of the correlation parameters among themselves. On the basis of the theory of scientific mathematical planning of the experiment, a set of corresponding experiments was carried out, which made it possible to build spatial graphic models.
Scientific novelty. For the first time, theoretical and practical scientific research is presented with the reproduction of a systemic multivariate analysis of the parameters of mathematical models and processes leading to the martensitic ( γ → α ) transformation and determines the substantiation of the chemical composition of the deposited materials to increase fracture resistance under conditions of quasi-dissipative and dissipative tribosystems.
Practical meaning. The obtained results of the above studies allow, within the framework of technical and technological accuracy, which is necessary within the framework of practical engineering forecasts, to determine the physical and mechanical properties of wear-resistant deposited alloys under conditions of quasi-dissipative and dissipative tribosystems.
Research of technology of manufacturing of steeply curved bends
Authors: Lenok А. , Obdul V. , Vinovets O. 
Published: March 2021

Purpose of work. Investigation of the features of the technological process of manufacturing curvilinear sections of the pipeline – steeply curved bends.
Research methods. Three-dimensional modeling of a design of equipment and a finished product; experimental studies of the technology of manufacturing steeply curved bends by pushing through a curved hole of the assembly matrix without using fillers; estimation of deformation by the method of dividing grids.
Obtained results. Literary sources are analyzed and the main problems arising in the manufacture of steeply curved bends for each method are identified. To study the features of the manufacturing technology, a three-dimen­sional model of the assembly matrix was modeled using the investigated method, the design, dimensions and material of the tooling were selected. Equipment was made. Sizes and material of pipe billets were selected. The operations of the technology for the manufacture of steeply curved bends by pushing through a curved hole of the assembly matrix without the use of fillers were determined.
Experimental studies of the technology have been carried out. For this, the manufactured stamp was installed on a PG-100A hydraulic press. Pipe billets were placed in a guide sleeve, which was screwed to the assembly die when the press rod was placed in the upper position. The punch pushed the pipe billet along the curved hole of the assembly matrix while moving the rod down. Upon completion of the pushing process, the press rod was in the upper position. For unimpeded removal of the finished product, the guide sleeve was removed, the matrix was unscrewed and removed from the clamps.
Several samples were obtained, the presence of defects and problems that arose during the formation of steeply curved bends were revealed. To assess the deformation, the method of dividing grids was used.
Scientific novelty. The method of manufacturing steeply curved bends by pushing an assembly matrix through a curved hole was further developed. The peculiarity of the investigated technology - rejection of the use of expensive filler or rigid mandrels, reduction of technological operations and time for manufacturing a unit of a finished product. As a result of the study, dangerous zones of pipe billets in the process of manufacturing steeply curved bends were identified: the place of bending (crushing, corrugation, rupture) and the ends of the finished product at the exit (ovalization, distortion, breaks).
Practical value. To prevent the occurrence of dangerous zones during deformation of pipe billets and improve the quality of the finished products obtained, requirements were formulated for the design of the working elements of the developed stamp, the choice of optimal modes of the shaping process, the material and the optimal shape of the pipe billet.
Hellenic Strong-Motion Database with Uniformly Assigned Source and Site Metadata for the Period 1972–2015
Authors: Margaris Basil , Scordilis Emmanuel M. , Stewart Jonathan P. , Boore David M. , Theodoulidis Nikos , Kalogeras Ioannis , Melis Nikolaos S. , Skarlatoudis Andreas A. , Klimis Nikolaos , Seyhan Emel 
Published: March 2021

AbstractWe present a Hellenic database of intensity measures from uniformly processed strong ground motion recordings, together with metadata on earthquake source attributes and recording site conditions. The database consists of information from 471 earthquakes between 1973 and 2015 that produced 2993 usable recordings from 333 sites. A key element of this work is a unified presentation of data from two major data providers that operate in Greece (Institute of Engineering Seismology and Earthquake Engineering and the Institute of Geodynamics, National Observatory of Athens) along with a university-operated local urban array (University of Patras). Consistent procedures were applied to develop source parameters that include hypocenter locations, moment magnitudes (directly estimated or derived using a conversion procedure), fault-plane solutions, and finite-fault parameters (generally, for events with M&gt;6.0). The time-averaged shear-wave velocity in the upper 30 m parameter is provided for all 333 recording sites based on geophysical measurements where available (102) and proxy-based estimates otherwise. Most events are in the magnitude range of 3.8–7, occurred at shallow hypocentral depths (&lt;30  km), and provide data for rupture distances generally between 10 and 300 km. The combined ground motion, seismic source, and site database is anticipated to be useful for engineering applications, including ground-motion model development and time series selection for response-history analyses.
ARRU Phase Picker: Attention Recurrent-Residual U-Net for Picking SeismicP- andS-Phase Arrivals
Authors: Liao Wu-Yu , Lee En-Jui , Mu Dawei , Chen Po , Rau Ruey-Juin 
Published: March 2021

AbstractSeismograms are convolution results between seismic sources and the media that seismic waves propagate through, and, therefore, the primary observations for studying seismic source parameters and the Earth interior. The routine earthquake location and travel-time tomography rely on accurate seismic phase picks (e.g., P and S arrivals). As data increase, reliable automated seismic phase-picking methods are needed to analyze data and provide timely earthquake information. However, most traditional autopickers suffer from low signal-to-noise ratio and usually require additional efforts to tune hyperparameters for each case. In this study, we proposed a deep-learning approach that adapted soft attention gates (AGs) and recurrent-residual convolution units (RRCUs) into the backbone U-Net for seismic phase picking. The attention mechanism was implemented to suppress responses from waveforms irrelevant to seismic phases, and the cooperating RRCUs further enhanced temporal connections of seismograms at multiple scales. We used numerous earthquake recordings in Taiwan with diverse focal mechanisms, wide depth, and magnitude distributions, to train and test our model. Setting the picking errors within 0.1 s and predicted probability over 0.5, the AG with recurrent-residual convolution unit (ARRU) phase picker achieved the F1 score of 98.62% for P arrivals and 95.16% for S arrivals, and picking rates were 96.72% for P waves and 90.07% for S waves. The ARRU phase picker also shown a great generalization capability, when handling unseen data. When applied the model trained with Taiwan data to the southern California data, the ARRU phase picker shown no cognitive downgrade. Comparing with manual picks, the arrival times determined by the ARRU phase picker shown a higher consistency, which had been evaluated by a set of repeating earthquakes. The arrival picks with less human error could benefit studies, such as earthquake location and seismic tomography.
Inversion for Shear-Tensile Focal Mechanisms Using an Unsupervised Physics-Guided Neural Network
Authors: Zhang Hongliang , Innanen Kristopher A. , Eaton David W. 
Published: March 2021

AbstractWe present a novel physics-guided neural network to estimate shear-tensile focal mechanisms for microearthquakes using displacement amplitudes of direct P waves. Compared with conventional data-driven fully connected (FC) neural networks, our physics-guided neural network is implemented in an unsupervised fashion and avoids the use of training data, which may be incomplete or unavailable. We incorporate three FC layers and a scaling and shifting layer to estimate shear-tensile focal mechanisms for multiple events. Then, a forward-modeling layer, which generates synthetic amplitude data based on the source mechanisms emerging from the previous layer, is added. The neural network weights are iteratively updated to minimize the mean squared error between observed and modeled normalized P-wave amplitudes. We apply this machine-learning approach to a set of 530 induced events recorded during hydraulic-fracture simulation of Duvernay Shale west of Fox Creek, Alberta, yielding results that are consistent with previously reported source mechanisms for the same dataset. A distinct cluster characterized by more complex mechanisms exhibits relatively large Kagan angles (5°–25°) compared with the previously reported best double-couple solutions, mainly due to model simplification of the shear-tensile focal mechanism. Uncertainty tests demonstrate the robustness of the inversion results and high tolerance of our neural network to errors in event locations, the velocity model, and P-wave amplitudes. Compared with a single-event grid-search algorithm to estimate shear-tensile focal mechanisms, the proposed neural network approach exhibits significantly higher computational efficiency.
Prospective study on the clinico-hematological profile of dengue fever patients in Navi Mumbai
Authors: Sankhe Prachi , Jadhav Priyanka , Meduri Praveen 
Published: March 2021

Background: It has been seen that epidemiology and clinical presentation of dengue infection differs significantly across geographical areas. The present study was done to study clinico-hematological profile of patients with dengue fever in Navi Mumbai, Maharashtra.Methods: This prospective observational study was conducted at a tertiary level teaching hospital in Navi Mumbai. All patients were observed over their entire duration of their hospital stay (up to 7 days). We included adult patients of both gender (males or females) who were admitted with clinically and serological diagnosed dengue fever, consenting to participate in the study. The clinical, laboratory and radiological findings of the patients were noted.Results: All 80 patients presented with fever while 71.25% had myalgia. Retro-orbital pain, rash and vomiting was observed in 38%, 26% and 26% respectively, whereas 23.75% patients were having cough and bleeding from any site. Three fourths of the patients were diagnosed with dengue, 18.75% and 6.25% were diagnosed with DHF and DSS. respectively. Hepatosplenomegaly was increasing from day 1 (9%) to 6th (60%) and 7th (60%) day. Mean haemoglobin levels and haematocrit started increasing from second day onwards, while WBC count and platelet count increased gradually from first day onwards. Splenomegaly was diagnosed in 3.75% of patients while hepatosplenomegaly and fatty liver was observed in 8.75% and 2.5% respectively. There were two deaths, both were cases of DSS.Conclusions: Almost all the patients included in our study showed both haematological and biochemical abnormalities.
A clinical study to evaluate the role of Madhumehari Vati in the management of Madhumeha type 2 diabetes
Authors: Sharma Sachin Kumar , Dave Alankruta R. , Vasishth Brijbala , Sharma Vasundhara 
Published: March 2021

Background: Type 2 Diabetes is a major, non-communicable disease with increasing prevalence at the global level. Type 2 diabetes is a metabolic disorder which can be correlated with Madhumeha. Madhumeha is Tridoshaj in origin with predominance of Vata and Kapha. Type 2 diabetes results when the body produces insufficient insulin or the body cannot use the insulin it produces. Most of the contents of Madhumehari Vati are having Katu (pungent), Tikta (bitter), Kashaya (astringent) Rasa (taste), Laghu (light), Ruksha (rough) Guna (properties), Katu (pungent) Vipaka (taste after digestion), Ushna (hot) Virya (potency), Deepana, Pachana Kapha-Pitta Shamaka properties and hypoglycaemic,antidiabetic activity,Hepatoprotective, hypolipidemic and antioxidant activities which are essential in the management of Madhumeha (type 2 diabetes). So, this study was taken up to evaluate the effectiveness of Madhumehari Vati in the management of Madhumeha (type 2 Diabetes). Aim of the study was to evaluate the efficacy of Madhumehari Vati in the management of Madhumeha w.s.r type 2 diabetes.Methods: Total 31 patients were selected from OPD of Kayachikitsa, department, I. T. R. A., Jamnagar. In this study Madhumehari Vati was given in dose of one tablet (1000 mg each) three times in a day with plain water before meal.Results: After the course of therapy for 8 weeks, statistically highly significant improvement was found in subjective parameters like Pindikodwestana (calf muscles cramps), Guru Gatrata (heaviness of body), Supti (numbness), Karapada Daha (burning sensation in palm and soles), Prabhutamutrata (polyuria), Atipipasa (polydipsia) whereas Shithila Angata (flaccidity of body parts), Swedadhikya (excessive sweating), Kshudha Adhikya (polyphasia) and Nidra Adhikya (excessive sleep) remained statistically significant (p<0.05). In objective parameters statistically highly, significant improvement was found in post prandial blood glucose whereas statistically significant improvement was found fasting blood glucose and HbA1C.Conclusions: Madhumehari Vati is effective in the management of Madhumeha (type 2 diabetes). No ADR (adverse drug reaction) was reported during the study.
Estudos e Pesquisas sobre Aspectos Psicológicos da Obesidade em Adolescentes
Authors: Tomaz Renata S. R. , Zanini Daniela Sacramento 
Published: March 2021

Resumo: este artigo pretende descrever, através de estudo de revisão sistemática em duas bases de dados brasileiras (Scielo e BDTD), aspectos psicológicos da obesidade em adolescente brasileiros. São poucos os estudos relacionados com esta temática no Brasil: no Scielo apenas 0,08% e no Banco de Dados de Teses e Dissertações, 1,2%. Observa-se a importância de se desenvolver estudos nesta área.
Palavras-chave: Obesidade. Adolescência. Aspectos psicológicos
Paradigma do Autocontrole e o Tratamento da Obesidade
Authors: Lima Diego Da Silva , Baia Fábio Henrique , Bravin André Amaral , Costa Laureane Marília de Lima , Pereira Raiene Sara Cardoso 
Published: March 2021

Resumo: obesidade é uma doença multifatorial crônica que proporciona vários males a saúde. Terapia Comportamental é um tratamento que objetiva o manejo de contingências para a mudança do comportamento alimentar e alteração do peso corporal. Este estudo sugere (a) possíveis estratégias terapêuticas, e (b) expõem a possibilidade do emprego do paradigma de autocontrole como estratégia terapêutica principal para o tratamento deste problema de saúde.
Palavras-chave: Obesidade.Terapia Analítico Comportamental. Autocontrole. Impulsividade. Análise Comportamental Aplicada.
Ganho Ponderal Excessivo em Gestantes Atendidas em Serviço Público de Alto Risco
Authors: Godinho Jordana Carolina Marques , Rezio Marília Arantes , Da Silva Ludimila Pereira , Freitas Ana Tereza Vaz , Martins Karine Anusca , Do Amaral Waldemar Naves 
Published: March 2021

Resumo: o objetivo deste artigo é descrever o perfil de gestantes, em pré-natal de alto risco, e avaliar os fatores de risco associados ao ganho de peso excessivo, em uma maternidade pública. O ganho de peso gestacional excessivo foi associado ao diagnóstico de SHG e DMG, mulheres mais velhas que se encontravam no terceiro trimestre, com um intervalo, entre as gestações, superior a dois anos.
Palavras-chave: Gestação; Avaliação nutricional; Ganho de Peso; Perfil epidemiológico.