Second Stage
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Rongrong Xuan ◽  
Mingshuwen Yang ◽  
Yajie Gao ◽  
Shuaijun Ren ◽  
Jialin Li ◽  

Pelvic floor disorder (PFD) is a common disease affecting the quality of life of middle-aged and elderly women. Pelvic floor muscle (PFM) damage is related to delivery mode, fetal size, and parity. Spontaneous vaginal delivery causes especially great damage to PFM. The purpose of this study was to summarize the characteristics of PFM action during the second stage of labor by collecting female pelvic MRI (magnetic resonance imaging) data and, further, to try to investigate the potential pathogenetic mechanism of PFD. A three-dimensional model was established to study the influence factors and characteristics of PFM strength. In the second stage of labor, the mechanical responses, possible damage, and the key parts of postpartum lesions of PFM due to the different fetal biparietal diameter (BPD) sizes were analyzed by finite element simulations. The research results showed that the peak stress and strain of PFM appeared at one-half of the delivery period and at the attachment point of the pubococcygeus to the skeleton. In addition, during the simulation process, the pubococcygeus was stretched by about 1.2 times and the levator ani muscle was stretched by more than two-fold. There was also greater stress and strain in the middle area of the levator ani muscle and pubococcygeus. According to the statistics, either being too young or in old maternal age will increase the probability of postpartum PFM injury. During delivery, the entire PFM underwent the huge deformation, in which the levator ani muscle and the pubococcygeus were seriously stretched and the attachment point between the pubococcygeus and the skeleton were the places with the highest probability of postpartum lesions.

2021 ◽  
Vol 48 (3) ◽  
pp. 5-18
Francesco Ardolino

What is the role of translation in Maragall’s work? If his first goal was to bestow cultural support to Catalan literature with the addition of the European authors of Modernism, the second stage of the Catalan poet’s agenda becomes more ambitious, delving into the origins of Western literature and culminating in the translation of the Homeric Hymns. My contribution analyzes how, on the one hand, the Catalan rewriting of the works of Nietzsche, Goethe, Novalis, or Dante draws a progressive and continuous line within Maragall’s ideas; and, on the other hand, what impact these versions have on his own literary creation, through the loanwords that spread across his translations, and his poetry.

2021 ◽  
Vol 28 (3) ◽  
pp. 234-237
Gleb D. Stepanov

This article describes an algorithm for obtaining a non-negative basic solution of a system of linear algebraic equations. This problem, which undoubtedly has an independent interest, in particular, is the most time-consuming part of the famous simplex method for solving linear programming problems.Unlike the artificial basis Orden’s method used in the classical simplex method, the proposed algorithm does not attract artificial variables and economically consumes computational resources.The algorithm consists of two stages, each of which is based on Gaussian exceptions. The first stage coincides with the main part of the Gaussian complete exclusion method, in which the matrix of the system is reduced to the form with an identity submatrix. The second stage is an iterative cycle, at each of the iterations of which, according to some rules, a resolving element is selected, and then a Gaussian elimination step is performed, preserving the matrix structure obtained at the first stage. The cycle ends either when the absence of non-negative solutions is established, or when one of them is found.Two rules for choosing a resolving element are given. The more primitive of them allows for ambiguity of choice and does not exclude looping (but in very rare cases). Use of the second rule ensures that there is no looping.

2021 ◽  
Vol 9 (4) ◽  
pp. 852-859
Clement Ayarebilla Ali ◽  

The study compared exhaustively the Successive Approximation Model (SAM) and Analyze, Design, Develop, Implement and Evaluate (ADDIE) model on the teaching and learning of Science, Technology, Engineering and Mathematics subjects in Ghana. We selected a sample of 30 student-teachers who offered Mathematics and Science in the distance mode of the University of Education, Winneba, Ghana in the 2018/2019 academic year. The first stage of the analysis compared the models separately within the Vygotskian framework using pre-post experiemtal design. The second stage made comparisons between and within the two models. The results of both stages showed that student-teachers preferred mostly SAM to ADDIE instructional models. There were not only consistently higher mean gains in the latter model, but the group averages of student-teachers in the post-treatment results also demonstrated clear improvements. Again, student-teachers showed tremendous improvements in the conceptual understanding of both models. However, the Successive Approximation Model recorded much more improvements in both pre-treatment and post-treatment results. It was therefore imperative to conclude that the Successive Approximation Model was more properly situated in the context of teaching and learning Mathematics and Science. We, therefore, recommended experimental explorations of SAM for STEM.

2021 ◽  
Vol 11 (3) ◽  
pp. 375-386
Ilya M. Kagantsov ◽  
Vladimir G. Bairov ◽  
Anna A. Sukhotskaya ◽  
Tatiana M. Pervunina ◽  
Olga A. Li ◽  

BACKGROUND: The pentalogy of Cantrell is a rare congenital malformation characterized by five component defects in the anterior abdominal wall, lower sternum, anterior diaphragm, and diaphragmatic pericardium and congenital heart disease. The occurrence of the five features is quite rare. The pentalogy of Cantrell is classified as complete, partial, and incomplete. Few studies have described the successful treatment of neonates with the pentalogy of Cantrell, with even fewer publications about an incomplete defect. CASE REPORT: We report the successful surgical treatment of a newborn boy with an incomplete pentalogy of Cantrell. In this patient, the diaphragmatic hernia was eliminated at the first stage, and a temporary container for umbilical cord hernia was made by suturing the silastic sac to the edges of the defect in the anterior abdominal wall for subsequent gradual immersion of the hernia contents into the abdominal cavity. These steps made it possible to reduce intra-abdominal and, accordingly, intrathoracic pressures, provide favorable conditions for the healing of the diaphragm, and thus stabilize the childs respiratory and cardiovascular systems. Subsequently, the cardiovascular system was examined under more favorable conditions and intracardiac defects were excluded. Moreover, the proposed technique made it possible to safely perform the second stage of surgical correction, i.e., radical plasty of the anterior abdominal wall on day 14 of life with full restoration of the normal anatomical and physiological relationships, by which time the diaphragm and mediastinum had taken their correct topographic position. The literature review provides data from 32 sources. CONCLUSION: The pentalogy of Cantrell is a severe congenital malformation with a high risk of poor outcomes. Reporting of all possible variants of the pentalogy of Cantrell (complete, partial, or incomplete), regardless of the outcome, is important for the accumulation of experience in treating such patients, which by focusing on the clinical situation and the combination of various defects in the pentalogy of Cantrell will improve the strategy and prognosis for this defect.

Recycling ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 67
Guadalupe Martinez-Ballesteros ◽  
Jesus Leobardo Valenzuela-García ◽  
Agustin Gómez-Alvarez ◽  
Martin Antonio Encinas-Romero ◽  
Flerida Adriana Mejía-Zamudio ◽  

Reclamation of printed circuit boards (PCBs) to recover metals is gaining growing attention due to minerals being non-renewable resources. Currently, metals extraction from PCBs through an efficient and green method is still under investigation. The present investigation concerns the recycling of printed circuit boards using hydrometallurgical processes. First, the basic metals (Cu, Ni, Zn and Fe) were separated using a sulfuric acid solution at moderate temperatures. The remaining solids were characterized by SEM-EDS, whereby a high content of precious metals (Au, Ag and Pt) was observed. In the second stage, solids were leached with a solution of HCl and NaClO in a 1-L titanium reactor with varied oxygen pressure (0.2, 0.34 and 0.55 MPa), temperature (40, 50 and 80 °C) and concentration of HCl (2 and 4 M), obtaining extractions above 95% at [HCl] = 4 M, P = 0.34 MPa and T = 40 °C. The extraction increased depending on the concentration of HCl. Eh–pH diagrams for Ag–Cl–H2O, Au–Cl–H2O and Pt–Cl–H2O were constructed to know the possible species in the solution.

2021 ◽  
Almaz Makhmutovich Sadykov ◽  
Sergey Anatolyevich Erastov ◽  
Maxim Sergeevich Antonov ◽  
Denis Vagizovich Kashapov ◽  
Tagir Ramilevich Salakhov ◽  

Abstract One of the fundamental methods of developing low-permeability reservoirs is the use of multi-stage hydraulic fracturing in horizontal wells. Decreasing wells productivity requires geological and technical measures, where one of the methods is "blind" refracturing. Often, only one "blind" hydraulic fracturing is carried out for all ports of multistage hydraulic fracturing, the possibility of carrying out two or more stages of "blind" hydraulic fracturing is considered in this article. The purpose of the article is to increase the productivity of horizontal wells with multi-stage hydraulic fracturing by the "blind" refracturing method. A one-stage and two-stage approach was implemented when planning and performing "blind" hydraulic fracturing with analysis of treatment pressures, indicating a possibility for reorientation of the fracture during the second stage in a horizontal wellbore. Based on the experience of the "blind" hydraulic fracturing performed at the Kondinskoye field, "NK "Kondaneft" JSC carried out pilot work on "blind" refracturing at four horizontal wells of the Zapadno -Erginskoye field. A geomechanical model was used, built based on well logging and core studies carried out at "RN-BashNIPIneft" LLC. The total mass of the planned proppant per well was 280-290 tons, while this tonnage was pumped in one or more stages. A one-stage "blind" refracturing approach was successfully performed in one well, two-stage hydraulic fracturing was implemented in three wells, where in one of the wells, after two stages to open ports, initial hydraulic fracturing was also carried out to the last, previously non-activated port. In the case of two-stage hydraulic fracturing, the first stage purpose was to saturate the reservoir-fracture system with the injection of a "sand plug" with a high concentration of proppant at the end of the job to isolate the initial injectivity interval, determined based on the interpretation of well logging data and analysis of the wellhead treatment pressure. The second stage purpose was the initiation and possible reorientation of the fracture in a new interval, confirmed by an increase in surface pressure during hydraulic fracturing and instantaneous shut-in pressure. This article summarizes the results and lessons learned from the pilot works carried out using the geomechanical model and well productivity assessment before and after "blind" fracturing. The analysis of surface pressure based on production data indicating fracture reorientation is presented. The recommendations and accumulated experience presented in this work should increase the effectiveness of repeated "blind" refracturing in horizontal wells with multi-stage hydraulic fracturing.

2021 ◽  
Dmitry Moiseevich Olenchikov

Abstract Recently, more and more reservoir flow models are being extended to integrated ones to consider the influence of the surface network on the field development. A serious numerical problem is the handling of constraints in the form of inequalities. It is especially difficult in combination with optimization and automatic control of well and surface equipment. Traditional numerical methods solve the problem iteratively, choosing the operation modes for network elements. Sometimes solution may violate constraints or not be an optimal. The paper proposes a new flexible and relatively efficient method that allows to reliably handle constraints. The idea is to work with entire set of all possible operation modes according to constraints and control capabilities. Let's call this set an operation modes domain (OMD). The problem is solved in two stages. On the first stage (direct course) the OMD are calculated for all network elements from wells to terminal. Constraints are handled by narrowing the OMD. On the second stage (backward course) the optimal solution is chosen from OMD.

V. M. Artemiev ◽  
S. M. Kostromitsky ◽  
A. O. Naumov

To increase the efficiency of detecting moving objects in radiolocation, additional features are used, associated with the characteristics of trajectories. The authors assumed that trajectories are correlated, that allows extrapolation of the coordinate values taking into account their increments over the scanning period. The detection procedure consists of two stages. At the first, detection is carried out by the classical threshold method with a low threshold level, which provides a high probability of detection with high values of the probability of false alarms. At the same time uncertainty in the selection of object trajectory embedded in false trajectories arises. Due to the statistical independence of the coordinates of the false trajectories in comparison with the correlated coordinates of the object, the average duration of the first of them is less than the average duration of the second ones. This difference is used to solve the detection problem at the second stage based on the time-selection method. The obtained results allow estimation of the degree of gain in the probability of detection when using the proposed method.

2021 ◽  
Chen Li ◽  
Song-tao Shou ◽  
Yan-fen Chai

Abstract Background: The purpose of this study was to investigate the effect of the BOPPPS model (bridge-in, learning objective, pretest, participatory learning, posttest, and summary) with PAL (Peer-assisted learning) and medical humanities methods on Chinese Medical Students in Cardiopulmonary Resuscitation Courses. Methods: Participants were the long-term medical students of Tianjin Medical University who accepted emergency medicine courses from 2015 to 2020. Forward-looking descriptive research and phased CPR curriculum teaching innovation, including the BOPPS with PAL (First Stage), the BOPPS with PAL and medical humanities methods (Second Stage), compared with the traditional teaching model (Basic Stage). Results: The usual and final results improved in First stage compared with Basic stage (↑30.2%, ↑7.5%), the proportion of those with more than 80 points increased in the usual exam, and the proportion of those with 70 points or more increased in the final exam. The usual and final results improved in Second stage compared with First stage (↑12.0%, ↑2.2%), the proportion of those with more than 90 points increased in the usual exam, and the proportion of those with 80 points or more increased in the final exam. Conclusions: The teaching innovation of the CPR curriculum, the application of BOPPPS teaching model, and the peer-assisted learning and medical humanities teaching methods can improve teaching quality of CPR courses in medical colleges.

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