Introduction and Significance: Burn injury (BI) is a considerable health issue which is responsible for around 300,000 deaths and affecting about 11 million people every year worldwide. In Saudi Arabia, the prevalence...Introduction and Significance: Burn injury (BI) is a considerable health issue which is responsible for around 300,000 deaths and affecting about 11 million people every year worldwide. In Saudi Arabia, the prevalence of BIs array from 112 to 518 per 100,000 per year. The appropriate awareness of performing first aid could facilitate to improve the outcomes of burns. Purpose and Objectives: To appraise the community that acknowledges burns, first aid, and associated factors among the community population in Jazan City, Saudi Arabia. The paper aims to identify limitations to encourage additional research and persuade legislators to develop improved burn-injury care recommendations and training programs. Materials and Methods: An observational-based sample survey was conducted among the people who live in Jazan City aging 13 years or more, during April 5 to May 5, 2023. Data collection was done by a validated online self-administrated questionnaire sent randomly to community members in different parts of Jazan City via social media platforms. Collected data were coded and cleaned by an excel program, and finally exported on SPSS 26.0 software. The variables were analyzed using descriptive statistics like frequencies and percentages. Also, the Chi-square test was used to investigate the relation between different variables, with a significance value of P Results: This study included 243 participants (about 62%) among them were mostly male participants (151) having a university degree. The majority of participants 75% did not take any form of BFA training in the past. This study shows that 69.9% of the participants have inadequate awareness, despite 72% having a constructive attitude towards burn first aid. Previous burn-related first aid training was significantly associated with participants’ knowledge of BFA at a p-value less than 0.05. Conclusion: This study indicates a high frequency of Jazan population having inadequate knowledge of burn first aid despite the high prevalence of a favorable attitude. There is a need to develop an effective nationwide burn prevention program and early burn first aid treatment in Saudi Arabia and promote a consistent guideline for burn first aid.展开更多
To solve the first-order differential equation derived from the problem of a free-falling object and the problem arising from Newton’s law of cooling, the study compares the numerical solutions obtained from Picard’...To solve the first-order differential equation derived from the problem of a free-falling object and the problem arising from Newton’s law of cooling, the study compares the numerical solutions obtained from Picard’s and Taylor’s series methods. We have carried out a descriptive analysis using the MATLAB software. Picard’s and Taylor’s techniques for deriving numerical solutions are both strong mathematical instruments that behave similarly. All first-order differential equations in standard form that have a constant function on the right-hand side share this similarity. As a result, we can conclude that Taylor’s approach is simpler to use, more effective, and more accurate. We will contrast Rung Kutta and Taylor’s methods in more detail in the following section.展开更多
Objective: To investigate the application and feasibility of PDCA circulation method in the treatment of patients with severe neurological diseases in Internet + smart first aid, with a view to promoting the sustainab...Objective: To investigate the application and feasibility of PDCA circulation method in the treatment of patients with severe neurological diseases in Internet + smart first aid, with a view to promoting the sustainable construction of smart first aid. Methods: A total of 105 patients with severe neurological diseases in Zhuji people’s Hospital and cooperative units were selected, and 52 cases in the research group and 53 cases in the control group were divided according to the single and double number visiting time: In this paper, through reading the literature, the development of Internet + wisdom first aid treatment of patients with severe neurological diseases was investigated, and the common problems were analyzed and summarized, and the research group used the PDCA circulation method to sort out the existing problems, analyze the causes of the problems and improve them. The difference in treatment time between the two groups was compared, and the patient’s satisfaction was evaluated for the time of being transferred to the hospital emergency room by 120 ambulances, the time from emergency admission to surgery (Cath lab), and the satisfaction of the patient. Results: The time from emergency treatment to the operation room (catheter room) in the study group was significantly shortened, and patient satisfaction was significantly improved compared with that in the control group, with a statistically significant difference (P Conclusion: Through the application of PDCA circulation method in the Internet + smart emergency treatment of neurologically severe preoperative patients, the Internet + smart emergency mode can be continuously improved, the treatment process can be significantly optimized, the first aid time can be shortened, and the treatment efficiency of neurocritical ill patients can be improved. Therefore, it has been expected to improve the success rate of treatment and improve the success rate of neurological patients.展开更多
Syphilis and HIV are amongst the world’s most widespread diseases, particularly in low-income countries. Syphilis and HIV infections during pregnancy have been associated with numerous adverse pregnancy outcomes. Of ...Syphilis and HIV are amongst the world’s most widespread diseases, particularly in low-income countries. Syphilis and HIV infections during pregnancy have been associated with numerous adverse pregnancy outcomes. Of concern now are the rising rates of congenital syphilis and HIV in Cameroon. Cameroon only mandates testing pregnant women for syphilis and HIV during their first ANC visit. This study was aimed at determining the incidence of new syphilis and HIV infections and factors associated with pregnant women who previously tested negative during their first ANC visit. A cohort design was used, where 335 pregnant women were followed up for a period from December 2019 to August 2020. A blood sample was drawn and the serum was analyzed using the WANTAI ELISA and AIDTM HIV 1 + 2 Ag/Ab ELISAPlus test methods for syphilis and HIV respectively at three intervals. A questionnaire was used to identify risk factors. Data was analyzed using SPSS 23.0. Out of the 335 pregnant women who were followed up during this study, 49 (14.6%) were later diagnosed with syphilis (32 in 2<sup>nd</sup> trimester and 17 in 3<sup>rd</sup> trimester). 54 (16.1%) were diagnosed with HIV infection (13 at two months post-1<sup>st</sup>-trimester visit, 23 in the 2<sup>nd</sup> trimester and 18 in the 3rd trimester). Lastly, 10 (2%) were co-infected with syphilis and HIV of which 8 occurred during 2<sup>nd</sup> trimester and 2 in the 3<sup>rd</sup> trimester. The factors associated with contracting new syphilis infections include;younger age group aOR (1.302, 95% CI), leaving in an urban area aOR (3.158, 95% CI), lower level of education (Primary and no formal) with aOR of (9.055, 95% CI) (P = 0.001) and (6.764, 95% CI) (P = 0.006) respectively, inadequate knowledge on the diseases aOR (2.176, 95% CI), women unaware of their partner status aOR (3.190, 95% CI). Most factors associated with contracting new HIV infections were similar to the factors associated with contracting new syphilis infections post 1<sup>st</sup> ANC visit aOR (1.174, 95% CI) and pregnant women with more than one sexual partner aOR (7.342, 95% CI) were observed for HIV infection.. There is an increased incidence of new infection of syphilis and HIV post first ANC screening in the Buea Health District, Cameroon. The need for constant education on the identifiable factors and these diseases, and screening during every ANC visit irrespective of their previous laboratory results is warranted.展开更多
The internal energy change of ideal gas does not depend on the volume and pressure. The internal energy change of real gas has not any relation with the volume and pressure, which had been proved. If the internal ener...The internal energy change of ideal gas does not depend on the volume and pressure. The internal energy change of real gas has not any relation with the volume and pressure, which had been proved. If the internal energy change had not any relation with the volume and pressure, we could confirm the first law of thermodynamics in theory. Simultaneously, the internal energy change is the state function that shall be able to be proved in theory. If the internal energy change depended on the volume and pressure, we could not prove that the internal energy change is the state function and the chemical thermodynamics theory is right. The extended or modified Bernoulli equation can be derived from the energy conservation law, and the internal energy change, heat, and friction are all considered in the derivation procedure. The extended Bernoulli equation could be applied to the flying aircraft and mechanical motion on the gravitational field, for instance, the rocket and airplane and so on. This paper also revises some wrong ideas, viewpoints, or concepts about the thermodynamics theory and Bernoulli equation.展开更多
In the 19th century, Cantor created the infinite cardinal number theory based on the “1-1 correspondence” principle. The continuum hypothesis is proposed under this theoretical framework. In 1900, Hilbert made it th...In the 19th century, Cantor created the infinite cardinal number theory based on the “1-1 correspondence” principle. The continuum hypothesis is proposed under this theoretical framework. In 1900, Hilbert made it the first problem in his famous speech on mathematical problems, which shows the importance of this question. We know that the infinitesimal problem triggered the second mathematical crisis in the 17-18th centuries. The Infinity problem is no less important than the infinitesimal problem. In the 21st century, Sergeyev introduced the Grossone method from the principle of “whole is greater than part”, and created another ruler for measuring infinite sets. The discussion in this paper shows that, compared with the cardinal number method, the Grossone method enables infinity calculation to achieve a leap from qualitative calculation to quantitative calculation. According to Grossone theory, there is neither the largest infinity and infinitesimal, nor the smallest infinity and infinitesimal. Hilbert’s first problem was caused by the immaturity of the infinity theory.展开更多
The ligand o-phenylenediamine (opda) and its oxidized form, o-benzoquinonediimine (bqdi), act as a fascinating candidate coordinating toward transition metal ions leading to the photochemical hydrogen production in ab...The ligand o-phenylenediamine (opda) and its oxidized form, o-benzoquinonediimine (bqdi), act as a fascinating candidate coordinating toward transition metal ions leading to the photochemical hydrogen production in absence of photosensitizers. Herein, we report the systematic study of the interaction between the oxidized form bqdi ligand, tris-(o-benzoquinonediimine) with divalent first-row transition metal series using DFT calculations. The lowest energy structures, bond length, binding energies, frontier molecular orbital analysis, natural bond orbitals, and global reactivity descriptor were calculated using B3LYP/6-311G(d,P) level of theory. The time dependent-DFT at the CAM-B3LYP/6-311+G(d,p) level of theory was applied to determine the electronic structures and the optical spectra. The theoretical binding trend of the divalent first-row transition metal series is decreasing as follows: Cu >Ti > V > Co > Ni > Fe > Cr > Zn >Mn. Among them, the binding potency of iron (II) by the bqdi ligand was not predominantly sturdy as compared to other first-row divalent transition metal ions. The origin of strong coordination with Fe(II) is attributed to its extra capability to induce covalent coordination of bqdi ligands. The complex exhibited two strong peaks at 370 nm and 452 nm, due to the HOMO-3 to LUMO+1 and HOMO-1 to LUMO transitions, respectively. Natural bond orbital analysis showed that the major interaction happens between the N lone pair electrons of the ligand with an anti-bonding orbital of metal ions, in which Ti showed the highest interaction energy than other metal ions. The present systemic DFT study of bqdi ligands with the first-row transition metals strongly encourages the future establishment of photochemical hydrogen production in absence of photosensitizers.展开更多
Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollu...Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollutants. While catalytic decomposition and zeolites are traditional ways used to reduce the amount of these gases. We need to develop and explore new promising materials. Covalent organic framework (COF) has become an attractive platform for researcher due to its extended robust covalent bonds, porosity, and crystallinity. In this study, first principal calculations were performed for gases adsorption using COFs containing nitrogen and π-bonds. Different building blocks (BBs) and linkers (LINKs/LINK1 & LINK2) were investigated by means of density functional theory (DFT) calculations with B3LYP and 3-21G basis sets to calculate the binding energies of gases @COF systems. Electrostatic potential maps (ESPM), Mulliken charges and non-covalent interaction (NCI) are used to understand the type of interactions between gas and COFs fragments. O3 was found to bind strongly with COF system in comparison with NO which could make COF a useful selective material for mixed gases environment for sensing and removal application.展开更多
描述了多处理机环境中 FIRST 和 FOLLOW 集合求解的一种并行处理方法,并讨论了 FIRST 和 FOLLOW 集合的并行算法设计思想和它的实现策略,在构造文法 G 的 LL(1)分析表以及判定文法 G 是否 LL(1)文法时,求解 FIRST 和 FOLLOW 集合是很重...描述了多处理机环境中 FIRST 和 FOLLOW 集合求解的一种并行处理方法,并讨论了 FIRST 和 FOLLOW 集合的并行算法设计思想和它的实现策略,在构造文法 G 的 LL(1)分析表以及判定文法 G 是否 LL(1)文法时,求解 FIRST 和 FOLLOW 集合是很重要的内容,由于文法中终结符和非终结符个数很多,考虑 FIRST 和 FOLLOW 集合的并行处理方法,对并行编译处理和提高效率有其理论和现实意义。展开更多
The paper presents the simulation results of the comparison of three Queuing Mechanisms, First in First out (FIFO), Priority Queuing (PQ), and Weighted Fair Queuing (WFQ). Depending on their effects on the network’s ...The paper presents the simulation results of the comparison of three Queuing Mechanisms, First in First out (FIFO), Priority Queuing (PQ), and Weighted Fair Queuing (WFQ). Depending on their effects on the network’s Routers, the load of any algorithm of them over Router’s CPUs and memory usage, the delay occurred between routers when any algorithm has been used and the network application throughput. This comparison explains that, PQ doesn’t need high specification hardware (memory and CPU) but when used it is not fair, because it serves one application and ignore the other application and FIFO mechanism has smaller queuing delay, otherwise PQ has bigger delay.展开更多
By numerical integration of hydro-dynamical equations, we study the formation of elliptical and spiral galaxies starting from primordial linear density-velocity-gravitational perturbations. Both dark matter and baryon...By numerical integration of hydro-dynamical equations, we study the formation of elliptical and spiral galaxies starting from primordial linear density-velocity-gravitational perturbations. Both dark matter and baryons are included. Warm dark matter perturbations acquire two low mass cut-offs: the free-streaming cut-off due to the power spectrum free-streaming cut-off factor τ<sup>2</sup>(k), and the velocity dispersion cut-off. The Press-Schechter mass distribution does not include velocity dispersion, and should not be used below the velocity dispersion cut-off mass. From the formation of first galaxies and reionization, we estimate limits on the non-relativistic warm dark matter velocity dispersion at expansion parameter , with .展开更多
In the linguistic field,L1transfer is a complex and controversial field in second language acquisition.In this article,Firstly,it will discuss some historical theories of L1 transfer.Secondly,it will analyze some mani...In the linguistic field,L1transfer is a complex and controversial field in second language acquisition.In this article,Firstly,it will discuss some historical theories of L1 transfer.Secondly,it will analyze some manifestations of L1 transfer.Thirdly,it will explain the struc tural and the nonstructural factors in L1 transfer.Fourthly,it will discuss the problems in the study of L1transfer.Finally,it will give some my opinions of L1transfer.展开更多
文摘Introduction and Significance: Burn injury (BI) is a considerable health issue which is responsible for around 300,000 deaths and affecting about 11 million people every year worldwide. In Saudi Arabia, the prevalence of BIs array from 112 to 518 per 100,000 per year. The appropriate awareness of performing first aid could facilitate to improve the outcomes of burns. Purpose and Objectives: To appraise the community that acknowledges burns, first aid, and associated factors among the community population in Jazan City, Saudi Arabia. The paper aims to identify limitations to encourage additional research and persuade legislators to develop improved burn-injury care recommendations and training programs. Materials and Methods: An observational-based sample survey was conducted among the people who live in Jazan City aging 13 years or more, during April 5 to May 5, 2023. Data collection was done by a validated online self-administrated questionnaire sent randomly to community members in different parts of Jazan City via social media platforms. Collected data were coded and cleaned by an excel program, and finally exported on SPSS 26.0 software. The variables were analyzed using descriptive statistics like frequencies and percentages. Also, the Chi-square test was used to investigate the relation between different variables, with a significance value of P Results: This study included 243 participants (about 62%) among them were mostly male participants (151) having a university degree. The majority of participants 75% did not take any form of BFA training in the past. This study shows that 69.9% of the participants have inadequate awareness, despite 72% having a constructive attitude towards burn first aid. Previous burn-related first aid training was significantly associated with participants’ knowledge of BFA at a p-value less than 0.05. Conclusion: This study indicates a high frequency of Jazan population having inadequate knowledge of burn first aid despite the high prevalence of a favorable attitude. There is a need to develop an effective nationwide burn prevention program and early burn first aid treatment in Saudi Arabia and promote a consistent guideline for burn first aid.
文摘To solve the first-order differential equation derived from the problem of a free-falling object and the problem arising from Newton’s law of cooling, the study compares the numerical solutions obtained from Picard’s and Taylor’s series methods. We have carried out a descriptive analysis using the MATLAB software. Picard’s and Taylor’s techniques for deriving numerical solutions are both strong mathematical instruments that behave similarly. All first-order differential equations in standard form that have a constant function on the right-hand side share this similarity. As a result, we can conclude that Taylor’s approach is simpler to use, more effective, and more accurate. We will contrast Rung Kutta and Taylor’s methods in more detail in the following section.
文摘Objective: To investigate the application and feasibility of PDCA circulation method in the treatment of patients with severe neurological diseases in Internet + smart first aid, with a view to promoting the sustainable construction of smart first aid. Methods: A total of 105 patients with severe neurological diseases in Zhuji people’s Hospital and cooperative units were selected, and 52 cases in the research group and 53 cases in the control group were divided according to the single and double number visiting time: In this paper, through reading the literature, the development of Internet + wisdom first aid treatment of patients with severe neurological diseases was investigated, and the common problems were analyzed and summarized, and the research group used the PDCA circulation method to sort out the existing problems, analyze the causes of the problems and improve them. The difference in treatment time between the two groups was compared, and the patient’s satisfaction was evaluated for the time of being transferred to the hospital emergency room by 120 ambulances, the time from emergency admission to surgery (Cath lab), and the satisfaction of the patient. Results: The time from emergency treatment to the operation room (catheter room) in the study group was significantly shortened, and patient satisfaction was significantly improved compared with that in the control group, with a statistically significant difference (P Conclusion: Through the application of PDCA circulation method in the Internet + smart emergency treatment of neurologically severe preoperative patients, the Internet + smart emergency mode can be continuously improved, the treatment process can be significantly optimized, the first aid time can be shortened, and the treatment efficiency of neurocritical ill patients can be improved. Therefore, it has been expected to improve the success rate of treatment and improve the success rate of neurological patients.
文摘Syphilis and HIV are amongst the world’s most widespread diseases, particularly in low-income countries. Syphilis and HIV infections during pregnancy have been associated with numerous adverse pregnancy outcomes. Of concern now are the rising rates of congenital syphilis and HIV in Cameroon. Cameroon only mandates testing pregnant women for syphilis and HIV during their first ANC visit. This study was aimed at determining the incidence of new syphilis and HIV infections and factors associated with pregnant women who previously tested negative during their first ANC visit. A cohort design was used, where 335 pregnant women were followed up for a period from December 2019 to August 2020. A blood sample was drawn and the serum was analyzed using the WANTAI ELISA and AIDTM HIV 1 + 2 Ag/Ab ELISAPlus test methods for syphilis and HIV respectively at three intervals. A questionnaire was used to identify risk factors. Data was analyzed using SPSS 23.0. Out of the 335 pregnant women who were followed up during this study, 49 (14.6%) were later diagnosed with syphilis (32 in 2<sup>nd</sup> trimester and 17 in 3<sup>rd</sup> trimester). 54 (16.1%) were diagnosed with HIV infection (13 at two months post-1<sup>st</sup>-trimester visit, 23 in the 2<sup>nd</sup> trimester and 18 in the 3rd trimester). Lastly, 10 (2%) were co-infected with syphilis and HIV of which 8 occurred during 2<sup>nd</sup> trimester and 2 in the 3<sup>rd</sup> trimester. The factors associated with contracting new syphilis infections include;younger age group aOR (1.302, 95% CI), leaving in an urban area aOR (3.158, 95% CI), lower level of education (Primary and no formal) with aOR of (9.055, 95% CI) (P = 0.001) and (6.764, 95% CI) (P = 0.006) respectively, inadequate knowledge on the diseases aOR (2.176, 95% CI), women unaware of their partner status aOR (3.190, 95% CI). Most factors associated with contracting new HIV infections were similar to the factors associated with contracting new syphilis infections post 1<sup>st</sup> ANC visit aOR (1.174, 95% CI) and pregnant women with more than one sexual partner aOR (7.342, 95% CI) were observed for HIV infection.. There is an increased incidence of new infection of syphilis and HIV post first ANC screening in the Buea Health District, Cameroon. The need for constant education on the identifiable factors and these diseases, and screening during every ANC visit irrespective of their previous laboratory results is warranted.
文摘The internal energy change of ideal gas does not depend on the volume and pressure. The internal energy change of real gas has not any relation with the volume and pressure, which had been proved. If the internal energy change had not any relation with the volume and pressure, we could confirm the first law of thermodynamics in theory. Simultaneously, the internal energy change is the state function that shall be able to be proved in theory. If the internal energy change depended on the volume and pressure, we could not prove that the internal energy change is the state function and the chemical thermodynamics theory is right. The extended or modified Bernoulli equation can be derived from the energy conservation law, and the internal energy change, heat, and friction are all considered in the derivation procedure. The extended Bernoulli equation could be applied to the flying aircraft and mechanical motion on the gravitational field, for instance, the rocket and airplane and so on. This paper also revises some wrong ideas, viewpoints, or concepts about the thermodynamics theory and Bernoulli equation.
文摘In the 19th century, Cantor created the infinite cardinal number theory based on the “1-1 correspondence” principle. The continuum hypothesis is proposed under this theoretical framework. In 1900, Hilbert made it the first problem in his famous speech on mathematical problems, which shows the importance of this question. We know that the infinitesimal problem triggered the second mathematical crisis in the 17-18th centuries. The Infinity problem is no less important than the infinitesimal problem. In the 21st century, Sergeyev introduced the Grossone method from the principle of “whole is greater than part”, and created another ruler for measuring infinite sets. The discussion in this paper shows that, compared with the cardinal number method, the Grossone method enables infinity calculation to achieve a leap from qualitative calculation to quantitative calculation. According to Grossone theory, there is neither the largest infinity and infinitesimal, nor the smallest infinity and infinitesimal. Hilbert’s first problem was caused by the immaturity of the infinity theory.
文摘The ligand o-phenylenediamine (opda) and its oxidized form, o-benzoquinonediimine (bqdi), act as a fascinating candidate coordinating toward transition metal ions leading to the photochemical hydrogen production in absence of photosensitizers. Herein, we report the systematic study of the interaction between the oxidized form bqdi ligand, tris-(o-benzoquinonediimine) with divalent first-row transition metal series using DFT calculations. The lowest energy structures, bond length, binding energies, frontier molecular orbital analysis, natural bond orbitals, and global reactivity descriptor were calculated using B3LYP/6-311G(d,P) level of theory. The time dependent-DFT at the CAM-B3LYP/6-311+G(d,p) level of theory was applied to determine the electronic structures and the optical spectra. The theoretical binding trend of the divalent first-row transition metal series is decreasing as follows: Cu >Ti > V > Co > Ni > Fe > Cr > Zn >Mn. Among them, the binding potency of iron (II) by the bqdi ligand was not predominantly sturdy as compared to other first-row divalent transition metal ions. The origin of strong coordination with Fe(II) is attributed to its extra capability to induce covalent coordination of bqdi ligands. The complex exhibited two strong peaks at 370 nm and 452 nm, due to the HOMO-3 to LUMO+1 and HOMO-1 to LUMO transitions, respectively. Natural bond orbital analysis showed that the major interaction happens between the N lone pair electrons of the ligand with an anti-bonding orbital of metal ions, in which Ti showed the highest interaction energy than other metal ions. The present systemic DFT study of bqdi ligands with the first-row transition metals strongly encourages the future establishment of photochemical hydrogen production in absence of photosensitizers.
文摘Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollutants. While catalytic decomposition and zeolites are traditional ways used to reduce the amount of these gases. We need to develop and explore new promising materials. Covalent organic framework (COF) has become an attractive platform for researcher due to its extended robust covalent bonds, porosity, and crystallinity. In this study, first principal calculations were performed for gases adsorption using COFs containing nitrogen and π-bonds. Different building blocks (BBs) and linkers (LINKs/LINK1 & LINK2) were investigated by means of density functional theory (DFT) calculations with B3LYP and 3-21G basis sets to calculate the binding energies of gases @COF systems. Electrostatic potential maps (ESPM), Mulliken charges and non-covalent interaction (NCI) are used to understand the type of interactions between gas and COFs fragments. O3 was found to bind strongly with COF system in comparison with NO which could make COF a useful selective material for mixed gases environment for sensing and removal application.
文摘描述了多处理机环境中 FIRST 和 FOLLOW 集合求解的一种并行处理方法,并讨论了 FIRST 和 FOLLOW 集合的并行算法设计思想和它的实现策略,在构造文法 G 的 LL(1)分析表以及判定文法 G 是否 LL(1)文法时,求解 FIRST 和 FOLLOW 集合是很重要的内容,由于文法中终结符和非终结符个数很多,考虑 FIRST 和 FOLLOW 集合的并行处理方法,对并行编译处理和提高效率有其理论和现实意义。
文摘The paper presents the simulation results of the comparison of three Queuing Mechanisms, First in First out (FIFO), Priority Queuing (PQ), and Weighted Fair Queuing (WFQ). Depending on their effects on the network’s Routers, the load of any algorithm of them over Router’s CPUs and memory usage, the delay occurred between routers when any algorithm has been used and the network application throughput. This comparison explains that, PQ doesn’t need high specification hardware (memory and CPU) but when used it is not fair, because it serves one application and ignore the other application and FIFO mechanism has smaller queuing delay, otherwise PQ has bigger delay.
文摘By numerical integration of hydro-dynamical equations, we study the formation of elliptical and spiral galaxies starting from primordial linear density-velocity-gravitational perturbations. Both dark matter and baryons are included. Warm dark matter perturbations acquire two low mass cut-offs: the free-streaming cut-off due to the power spectrum free-streaming cut-off factor τ<sup>2</sup>(k), and the velocity dispersion cut-off. The Press-Schechter mass distribution does not include velocity dispersion, and should not be used below the velocity dispersion cut-off mass. From the formation of first galaxies and reionization, we estimate limits on the non-relativistic warm dark matter velocity dispersion at expansion parameter , with .
文摘In the linguistic field,L1transfer is a complex and controversial field in second language acquisition.In this article,Firstly,it will discuss some historical theories of L1 transfer.Secondly,it will analyze some manifestations of L1 transfer.Thirdly,it will explain the struc tural and the nonstructural factors in L1 transfer.Fourthly,it will discuss the problems in the study of L1transfer.Finally,it will give some my opinions of L1transfer.
