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A Sufficient Statistical Test for Dynamic Stability

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Journal of Data Analysis and Information Processing 2023年第2期11卷 144-174页

作者： Muhammad Ashfaq Ahmed Nasreen Nawaz federal board of revenue Islamabad Pakistan

In the existing Statistics and Econometrics literature, there does not exist a statistical test which may test for all kinds of roots of the characteristic polynomial leading to an unstable dynamic response, i.e., positive and negative real unit roots, complex unit roots and the roots lying inside the unit circle. This paper develops a test which is sufficient to prove dynamic stability (in the context of roots of the characteristic polynomial) of a univariate as well as a multivariate time series without having a structural break. It covers all roots (positive and negative real unit roots, complex unit roots and the roots inside the unit circle whether single or multiple) which may lead to an unstable dynamic response. Furthermore, it also indicates the number of roots causing instability in the time series. The test is much simpler in its application as compared to the existing tests as the series is strictly stationary under the null (C01, C12).

关键词： Dynamic Stability Real and Complex Roots Unit Circle

Study on the Estrous Cycle Regularity of Cryopreserved Rat Ovarian Tissues after Heterotopic Transplantation

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Open Journal of Obstetrics and Gynecology 2016年第5期6卷 293-298页

作者： Rumana Jafarey Syed Ali Rehan Shah Jaffri Reproductive Medical Centre Renmin Hospital of Wuhan University Wuhan China federal board of revenue Islamabad Pakistan

Objective: To evaluate the re-initiation of ovarian function in cryopreserved ovarian grafts by means of vaginal smear of transplant rats. Methods: A total of 40 SPF-SD female rats (5 - 6 week-old) were randomly divided into three groups (blank control, castration control and transplant group). Ovaries were removed by surgical procedure then after cryopreservation and thawing procedures the ovarian tissues pushed inside the back muscles gap in transplant group. On the first PO day, vaginal smear collection was daily initiated. After 30 days, the PO day when the estrous cycle was re-initiated was considered for analysis as well as the estrous days and the number of estrous cycles. Results: Normal control group had a regular estrous cycle, while the transplant group had an estrous cycle disorder within first 2 weeks and later 2 weeks after the transplantation while the duration of diestrus cycle lasted longer. At the same time, the castration group had lost the normal estrous cycle, keeping continue in the stage of diestrus. Conclusion: In transplanted animals the re-initiated ovarian function can be predicted with alteration between estrous and diestrus phases with predominant estrous irregularity. Moreover, short autotransplanted graft duration needs time to perfuse by new blood vessels and hormone secretions, so could not directly affect its target organs to function properly.

关键词： Transplantation Cryopreservation Thawing Vaginal Smear Ovarian Tissue Rats

The Chinese Export Boom:An Examination of the Detailed Trade Data

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China & World Economy 2013年第1期21卷 64-90页

作者： Brett Berger Robert F.Martin Division of International Finance Board of Governors of the Federal Reserve System Global Monetary and Sovereign Markets Division of International FinanceBoard of Governors of the Federal Reserve System

From 2000 to 2007, Chinese exports grew at a phenomenal pace. Our paper uses finely detailed Chinese export data （8-digit Harmonized Commodity Description and Coding System codes） combined with US trade data to explore how this was achieved. Although general explanations such as China ~ exchange rate policy no doubt played a role, we find that sector-specific stories, effective Chinese industrial policy and fortuitous timing were more critical The detailed trade data reveal that ＂＇new ＂＇ technology goods, such as cell phones, LCD screens and laptops, played a key role. Finally, we use the data to examine the relationship between Chinese exports and global manufacturing, in particular US manufacturing employment. We find that competition from China in both domestic and foreign markets likely contributed to a significant decline in USA manufacturing employment, but that relatively low US investment and slow GDP growth in the US following the 2001 recession played an equally important role.

关键词： China export manufacturing trade

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Scientometric Analysis of Research Output from Brazil in Response to the Zika Crisis Using e-Lattes

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Journal of Data and Information Science 2020年第4期5卷 137-146页

作者： Ricardo Barros Sampaio Antônio de Abreu Batista-Jr Bruno Santos Ferreira Mauricio LBarreto Jesús PMena-Chalco Regional board of Brasília Fiocruz Distrito FederalBrazil Department of Informatics federal University of Maranhão São LuísMABrazil Department of Teaching and Learning Studies Laval UniversityQuébecCanada Center of Integrated Data and Knowledge about Health(CIDACS) SalvadorBrazil Center for Mathematics Computation and CognitionFederal University of ABC Santo AndréSPBrazil

Purpose:This paper aims to test the use of e-Lattes to map the Brazilian scientific output in a recent research health subject:Zika ***/methodology/approach:From a set of Lattes CVs of Zika researchers registered on the Lattes Platform,we used the e-Lattes to map the Brazilian scientific response to the Zika ***:Brazilian science articulated quickly during the public health emergency of international concern(PHEIC)due to the creation of mechanisms to streamline funding of scientific *** limitations:We did not assess any dimension of research quality,including the scientific impact and societal *** implications:e-Lattes can provide useful guidelines for different stakeholders in research groups from Lattes CVs of ***/value:The information included in Lattes CVs permits us to assess science from a broader perspective taking into account not only scientific research production but also the training of human resources and scientific collaboration.

关键词： e-Lattes Zika virus Lattes Platform Brazilian research output Brazilian science

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APPLICATION OF OPTIMIZATION TO AIRCRAFT LANDING IN WIND SHEAR

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航空学报 1993年第8期 356-364页

作者： Bernd Kaufmann Technical University of Brauntschweig federal Republie of Germain

Aircraft landing in wind shear is dangerous. Many accidents have happened and a lot of research work has been done in this area. Whether an aircraft has enough capability to land in wind shear safely or not is not very clear vet. Using the real worst-case wind shear model and the optimization technique, the optima! open loop controls ol two civil aircraft landing in wind shear are found and it can easily be seen thai, generally speaking, an aircraft has potentiality to land in wind shear satelv. The problem hear is how to help the pilot detect the wind shear on board in lime and control the aircraft correctly and timelv.

关键词： wind shear optimization technique open loopeonlrol

Relationship of Pre-Existing Maternal/Caregiver Acute Respiratory Infection in the Pattern and Risk of Acute Respiratory Infection among Infants in Rivers State, Nigeria

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International Journal of Clinical Medicine 2018年第10期9卷 787-798页

作者： A. S. Ibama I. N. S. Dozie O. C. Abanobi A. N. Amadi G. Iwuoha T. Jaja P. Dennis federal University of Technology Owerri Nigeria University of Port Harcourt Teaching Hospital Port Harcourt Nigeria Rivers State Primary Health Care Management board Port Harcourt Nigeria

History of upper respiratory tract infection in the mother or siblings was associated with higher risk of acute lower respiratory tract infection in cases. Most upper respiratory tract infections were caused by viral pathogens and likely to occur in many members of the family. The study aimed to determine the existence and pattern of relationship between risk of acute respiratory infection (ARI) among infants and exposure to pre-existing maternal/caregiver acute respiratory tract infection. The study was designed as a community-based Nested case-control study of 1100 infants randomly selected from 12 communities out of 6 Local Government Areas of the 3 senatorial districts of Rivers State. A multistage random sampling technique was used in selecting the subjects up to the community level. Descriptive method was used to represent the characteristics of the subjects and the differences in ARI between exposed and unexposed infants were tested in a bivariate logistics regression at 5% level of significance. Odds ratio (OR) was used to interpret the size effect measures of ARI on exposure to pre-existing maternal/caregiver ARI differences. A total of 275 Cases of ARI and 825 controls were included in the study. Among exposed infants (N = 104), ARI cases were found to be higher n = 80 (76.9%) than in control n = 24 (23.1%). Whereas, among unexposed infants N = 991, ARI cases were found to be lower n = 195 (19.7%) than in control n = 796 (80.3%). For the exposed infants, the odds for ARI were 13.5 times significantly higher compared to those of their unexposed counterparts (OR-Unadjusted = 13.52, (p < 0.0001, 95% CI = 0.047 - 0.121)). The findings will widen the horizon in the etiological consideration of ARI among infants vis-à-vis exposure potential to pre-existing maternal/caregiver ARI via nursing care. Therefore, community-based sensitization programme on barrier nursing care techniques and personal hygiene practices should be on focus.

关键词： Acute-Respiratory-Infection Pattern Risk-Factor Maternal/Caregiver Pre-Existing Barrier-Nursing

Clinical Application of Dynamic Gait Index-Brazilian Brief Version

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Advances in Aging Research 2018年第6期7卷 113-118页

作者： Carlos Kazuo Taguchi élida Pinto Costa Lucas Vieira Alves Larissa Karoline Santos Erbson Rodrigues de Oliveira Silva Brenda Carla de Lima Araújo Fabíola Andréa Andrade dos Santos Allan Robert da Silva Audiology Departament Federal University of Sergipe S&atilde o Cristóvã o Brazil federal University of Sergipe S&atilde o Cristóvã o Brazil Education Coordinator of Sergipe State Aracaju Brazil Speech Therapist and Audiology Departament Federal University of Sergipe S&atilde o Cristóvã o Brazil University Hospital board Federal University of Sergipe S&atilde o Cristóvã o Brazil Statistical Departament Federal University of Sergipe S&atilde o Cristóvã o Brazil

Introduction: In elderly, the progressive degenerations in the nervous system and vestibular system compromise the human body balance leading to a greater risk of falls. The Dynamic Gait Index is a protocol that predicts risks to falls in seniors. Objective: To analyze the results of the application of the Dynamic Gait Index (DGI)-Brazilian brief proposal and establish correlation with the original version. Methods: Study approved by the Ethics and Research Committee of federal University of Sergipe (number 0197.0.107000.09). We analyzed 223 files of socially active elderly, female gender, aged ranged 60 to 85 years, mean 68.54 (±7.61) years since 2014. The volunteers were evaluated by the DGI-Brazil. For the statistical analysis, the Pearson Correlation Momentum Correlation Test with Spearman Correlation was used, with p ≤ 0.05 and r = 1.0. Results: Sixty-three (27.8%) of the volunteers presented an altered DGI scores. The statistical analysis indicated that Task 1 and Task 2 did not contribute to decrease the total score in the test. The worst performances occurred in Tasks 3, 5 and 6. There was founded a positive correlation between Tasks 1 and 2;1 and 8;3 and 4;3 and 5;4 and 5;2 and 4;2 and 7. Negative correlation occurred between Tasks 4 and 8, and 6 was not correlated with another Task. Conclusion: The DGI-Brazilian brief version presented an excellent correlation with the original proposal and may be useful in clinical practice as a tool to evidence future risks of falls in the elderly people.

关键词： Aged Postural Balance Accidental Falls Clinical Protocols

Toxicity for Aquatic Organisms of Antiretroviral Tenofovir Disoproxil

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Journal of Environmental Protection 2019年第12期10卷 1565-1577页

作者： S.R.Silva F.A.R.Barbosa M.P.G.Mol S.M.S.Magalhaes Department of Social Pharmacy Pharmacy SchoolFederal University of Minas GeraisBelo HorizonteMinas GeraisBrazil Department of General Biology Institute of Biological SciencesFederal University of Minas GeraisBelo HorizonteMinas GeraisBrazil Research and Development board Ezequiel Dias FoundationBelo HorizonteMinas GeraisBrazil

Tenofovir disoproxil fumarate is a prodrug, i.e. inative substance converted in vivo, after absorption to the active form deesterified tenofovir, which acts as an inhibitor of viral reverse transcriptase. To better understand the toxic effects of these drugs in the environment, three organisms were tested, the effective concentration (EC50) and inhibitory concentration (IC50) of tenofovir disoproxil that resulted in 50% growth inhibition of Microcystis novacekii, 50% immobilization of Artemia salina, and 50% loss of bioluminescence of Aliivibrio fischeri were evaluated. The EC50 value after 96 h of treatment for the cyanobacterium was 161.01 (156.81 - 165.21) mg·L-1;the IC50 value for A. salina after 24 h of treatment was 111.82 (103.18 - 120.45) mg·L-1;and the IC50 at 15 min for A. fischeri was 14.83 (13.87 - 15.79) mg·L-1. The test organism most sensitive to the drug was A. fischeri, indicating the importance of using representative models at different trophic levels to assess the potential risk of drugs for environmental toxicity. These results highlight the possible effect of tenofovir disoproxil on decomposer organisms, which may contribute to the environmental persistence of this drug.

关键词： Emerging Contaminant Aliivibrio fischeri Artemia salina Microcystis novacekii

Unsteady boundary layer flow and heat transfer over an exponentially shrinking sheet with suction in a copper-water nanofluid

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Journal of Central South University 2015年第12期22卷 4856-4863页

作者： Aurang Zaib Krishnendu Bhattacharyya Sharidan Shafie Department of Mathematical Sciences Federal Urdu University of ArtsScience & Technology Department of Mathematics The University of Burdwan Department of Mathematical Sciences Faculty of ScienceUniversiti Teknologi Malaysia

An analysis of unsteady boundary layer flow and heat transfer over an exponentially shrinking porous sheet filled with a copper-water nanofluid is *** is treated as a base *** the investigation,non-uniform mass suction through the porous sheet is *** Keller-box method the transformed equations are solved *** results of skin friction coefficient,the local Nusselt number as well as the velocity and temperature profiles are presented for different flow *** results showed that the dual non-similar solutions exist only when certain amount of mass suction is applied through the porous sheet for various unsteady parameters and nanoparticle volume *** ranges of suction where dual non-similar solution exists,become larger when values of unsteady parameter as well as nanoparticle volume fraction ***,due to unsteadiness of flow dynamics and the presence of nanoparticles in flow field,the requirement of mass suction for existence of solution of boundary layer flow past an exponentially shrinking sheet is ***,the velocity boundary layer thickness decreases and thermal boundary layer thickness increases with increasing of nanoparticle volume fraction in both non-similar ***,for stronger mass suction,the velocity boundary layer thickness becomes thinner for the first solution and the effect is opposite in the case of second *** temperature inside the boundary layer increases with nanoparticle volume fraction and decreases with mass ***,for the unsteadiness and for the presence of nanoparticles,the flow separation is delayed to some extent.

关键词： unsteady boundary layer heat transfer nanofluid exponentially shrinking sheet dual non-similar solutions

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