SMALL FIRM AND STOCK RETURN SEASONALITY: (NEW) EVIDENCE FROM THE LISBON STOCK EXCHANGE

Jose Adelino,Sang phill Kim People&Global Business Association 1996 Global Business and Finance Review Vol.1 No.2

This study examines, month In month. the empirical relation between market value and abnormal returns for the Lisbon Exchange listed stocks. Evidence is provided that supports a "size effect", where the market value is positively related to abnormal returns and selling pressure surrogates have a significant role in explaining excess returns for size ranked portfolios. The results show that size is positively related with abnormal returns for the January to September returns and that the effect is partially reversed for the last three months of the year. This evidence is unaffected when thin trading is token into account by using alternative beta estimation methods; however, it is partly explained by the market trading patterns.

A comprehensive FE model for slender HSC columns under biaxial eccentric loads

Tiejiong Lou,Sergio M.R. Lopes,Adelino V. Lopes,Wei Sun 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.73 No.1

A finite element (FE) model for analyzing slender reinforced high-strength concrete (HSC) columns under biaxial eccentric loading is formulated in terms of the Euler-Bernoulli theory. The cross section of columns is divided into discrete concrete and reinforcing steel fibers so as to account for varied material properties over the section. The interaction between axial and bending fields is introduced in the FE formulation so as to take the large-displacement or P-delta effects into consideration. The proposed model aims to be simple, user-friendly, and capable of simulating the full-range inelastic behavior of reinforced HSC slender columns. The nonlinear model is calibrated against the experimental data for slender column specimens available in the technical literature. By using the proposed model, a numerical study is carried out on pin-ended slender HSC square columns under axial compression and biaxial bending, with investigation variables including the load eccentricity and eccentricity angle. The calibrated model is expected to provide a valuable tool for more efficiently designing HSC columns.

FE modeling of inelastic behavior of reinforced high-strength concrete continuous beams

Lou, Tiejiong,Lopes, Sergio M.R.,Lopes, Adelino V. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.3

A finite element model for predicting the entire nonlinear behavior of reinforced high-strength concrete continuous beams is described. The model is based on the moment-curvature relations pre-generated through section analysis, and is formulated utilizing the Timoshenko beam theory. The validity of the model is verified with experimental results of a series of continuous high-strength concrete beam specimens. Some important aspects of behavior of the beams having different tensile reinforcement ratios are evaluated. In addition, a parametric study is carried out on continuous high-strength concrete beams with practical dimensions to examine the effect of tensile reinforcement on the degree of moment redistribution. The analysis shows that the tensile reinforcement in continuous high-strength concrete beams affects significantly the member behavior, namely, the flexural cracking stiffness, flexural ductility, neutral axis depth and redistribution of moments. It is also found that the relation between the tensile reinforcement ratios at critical negative and positive moment regions has great influence on the moment redistribution, while the importance of this factor is neglected in various codes.

Redistribution of moments in reinforced high-strength concrete beams with and without confinement

Tiejiong Lou,Sergio M.R. Lopes,Adelino V. Lopes 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.2

Confinement is known to have important influence on ductility of high-strength concrete (HSC) members and it may therefore be anticipated that this parameter would also affect notably the moment redistribution in these members. The correctness of this “common-sense knowledge” is examined in the present study. A numerical test is performed on two-span continuous reinforced HSC beams with and without confinement using an experimentally validated nonlinear model. The results show that the effect of confinement on moment redistribution is totally different from that on flexural ductility. The moment redistribution at ultimate limit state is found to be almost independent of the confinement, provided that both the negative and positive plastic hinges have formed at failure. The numerical findings are consistent with tests performed on prototype HSC beams. Several design codes are evaluated. It is demonstrated that the code equations by Eurocode 2 (EC2), British Standards Institution (BSI) and Canadian Standards Association (CSA) can well reflect the effect of confinement on moment redistribution in reinforced HSC beams but the American Concrete Institute (ACI) code cannot.

FE modeling of inelastic behavior of reinforced high-strength concrete continuous beams

Tiejiong Lou,Sergio M.R. Lopes,Adelino V. Lopes 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.3

A finite element model for predicting the entire nonlinear behavior of reinforced high-strengthconcrete continuous beams is described. The model is based on the moment-curvature relations pre-generated through section analysis, and is formulated utilizing the Timoshenko beam theory. The validity of the model is verified with experimental results of a series of continuous high-strength concretebeam specimens. Some important aspects of behavior of the beams having different tensile reinforcement ratios are evaluated. In addition, a parametric study is carried out on continuous high-strength concrete beams with practical dimensions to examine the effect of tensile reinforcement on the degree of moment redistribution. The analysis shows that the tensile reinforcement in continuous high-strength concrete beamsaffects significantly the member behavior, namely, the flexural cracking stiffness, flexural ductility, neutral axis depth and redistribution of moments. It is also found that the relation between the tensile reinforcement ratios at critical negative and positive moment regions has great influence on the moment redistribution, while the importance of this factor is neglected in various codes.

Numerical modelling of nonlinear behaviour of prestressed concrete continuous beams

Tiejiong Lou,Sergio M.R. Lopes,Adelino V. Lopes 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.15 No.3

The development of a finite element model for the geometric and material nonlinear analysis of bonded prestressed concrete continuous beams is presented. The nonlinear geometric effect is introduced by the coupling of axial and flexural fields. A layered approach is applied so as to consider different material properties across the depth of a cross section. The proposed method of analysis is formulated based on the Euler-Bernoulli beam theory. According to the total Lagrangian description, the constructed stiffness matrix consists of three components, namely, the material stiffness matrix reflecting the nonlinear material effect, the geometric stiffness matrix reflecting the nonlinear geometric effect and the large displacement stiffness matrix reflecting the large displacement effect. The analysis is capable of predicting the nonlinear behaviour of bonded prestressed concrete continuous beams over the entire loading stage up to failure. Some numerical examples are presented to demonstrate the validity and applicability of the proposed model.

Frailty-Independent Undertreatment Negative Impact on Survival in Older Patients With Breast Cancer

Fernando Osório,António S. Barros,Bárbara Peleteiro,Ana Rita Barradas,Joana Urbano,José Luís Fougo,Adelino Leite-Moreira 한국유방암학회 2021 Journal of breast cancer Vol.24 No.6

Purpose: The management of older adults with breast cancer (BC) remains controversial. The challenging assessment of aging idiosyncrasies and the scarce evidence of therapeutic guidelines can lead to undertreatment. Our goal was to measure undertreatment and assess its impact on survival. Methods: Consecutive patients with BC aged 70 years or older were prospectively enrolled in 2014. Three frailty screening tools (G8, fTRST, and GFI) and two functional status scales (Karnofsky performance score and Eastern Cooperative Oncology Group Performance Status) were applied. Disease characteristics, treatment options, and causes of mortality were recorded during a 5-year follow-up. In addition, we defined undertreatment and correlated its survival impact with frailty. Results: A total of 92 patients were included in the study. The median age was 77 (range 70–94) years. The prevalence of frailty was discordant (G8, 41.9%; fTRST, 74.2%; GFI, 32.3%). Only 47.8% of the patients had a local disease, probably due to a late diagnosis (73.9% based on self-examination). Thirty-three patients (35.6%) died, of which 15 were from BC. We found a considerably high proportion (53.3%) of undertreatment, which had a frailty-independent negative impact on the 5-year survival (hazard ratio [HR], 5.1; 95% confidence interval [CI], 2.1–12.5). Additionally, omission of surgery had a frailty-independent negative impact on overall survival (HR, 3.9; 95% CI, 1.9–7.9). Conclusion: BC treatment in older adults should be individualized. More importantly, assessing frailty (not to treat) is essential to be aware of the risk-benefit profile and the patient's well-informed willingness to be treated. Undertreatment in daily practice is frequent and might have a negative impact on survival, as we report.

Biomechanical behavior of CAD/CAM cobalt-chromium and zirconia full-arch fixed prostheses

Barbin, Thais,Silva, Leticia Del Rio,Veloso, Daniele Valente,Borges, Guilherme Almeida,Presotto, Anna Gabriella Camacho,Barao, Valentim Adelino Ricardo,Groppo, Francisco Carlos,Mesquita, Marcelo Ferra The Korean Academy of Prosthodonitics 2020 The Journal of Advanced Prosthodontics Vol.12 No.6

PURPOSE. To verify the influence of computer-aided design/computer-aided manufacturing (CAD/CAM) implant-supported prostheses manufactured with cobalt-chromium (Co-Cr) and zirconia (Zr), and whether ceramic application, spark erosion, and simulation of masticatory cycles modify biomechanical parameters (marginal fit, screw-loosening torque, and strain) on the implant-supported system. MATERIALS AND METHODS. Ten full-arch fixed frameworks were manufactured by a CAD/CAM milling system with Co-Cr and Zr (n=5/group). The marginal fit between the abutment and frameworks was measured as stated by single-screw test. Screw-loosening torque evaluated screw stability, and strain analysis was explored on the implant-supported system. All analyses were performed at 3 distinct times: after framework manufacturing; after ceramic application in both materials' frameworks; and after the spark erosion in Co-Cr frameworks. Afterward, stability analysis was re-evaluated after 106 mechanical cycles (2 Hz/150-N) for both materials. Statistical analyses were performed by Kruskal-Wallis and Dunn tests (α=.05). RESULTS. No difference between the two materials was found for marginal fit, screwloosening torque, and strain after framework manufacturing (P>.05). Ceramic application did not affect the variables (P>.05). Spark erosion optimized marginal fit and strain medians for Co-Cr frameworks (P<.05). Screw-loosening torque was significantly reduced by masticatory simulation (P<.05) regardless of the framework materials. CONCLUSION. Co-Cr and Zr frameworks presented similar biomechanical behavior. Ceramic application had no effect on the biomechanical behavior of either material. Spark erosion was an effective technique to improve Co-Cr biomechanical behavior on the implant-supported system. Screw-loosening torque was reduced for both materials after masticatory simulation.