A multifactor model of stock returns with endogenous regime switching

We estimate a state-dependent multifactor model with two endogenous states. Its pricing accuracy is slightly superior to that of the Fama and French (1993, 1996) model. We have evidence for dramatically increased factor loadings for distress factors in one state. These results have implications for cost-of-capital calculations, portfolio management, risk analysis and other applications.Empirical asset pricing, endogenous regime switching, state-dependent models, nonstandard maximum-likelihood estimation

The effects of 6-weeks program of physical therapeutic exergames on cognitive flexibility focused by reaction times in relation to manual and podal motor abilities

The main purpose of the study was to identify the level of improvement in cognitive flexi-bility manifested by choice and cognition reaction times in relation to manual and podal skills as a result of the implementation of a program of therapeutic exergame exercises, for a time interval of 6 weeks at the level of students. 511 students participated in the cross-sectional study, of which 279 male (54.6%) and 232 female (45.4%), divided into two groups: the experimental group 266 (521%) subjects and the control group 245 (48%) sub-jects. The implementation of the experimental program comprising of 8 physical thera-peutic exergames took place for 6 weeks, in one session per week, within the physical edu-cation lessons, only for the male and female experimental groups. In the initial and final testing session, 2 standardized tests were applied: TMT part A, B and 2 tests adapted for this study: Square Test and 25 Squares Test. The progress registered by the male and fe-male experimental groups was statistically significant. In all tests, the experimental groups showed higher progress compared to the control groups. Depending on the gender differences, it was found that the male experimental and control groups made better pro-gress compared to the female groups in the following tests: TMT part A, Square Test, 25 Squares Tests. The implementation of a physical therapeutic exergame program deter-mined the improvement of cognitive flexibility man-ifested by choice and cognitive reac-tion times in conditions of manual and podal motor skills, demonstrating the effective-ness of exergame technologies adapted and implemented for prophy-lactic purpose

Research and Science Today No. 1(5)/2013

Research and Science Today Journal is a publication founded in 2011 and it is dedicated to the students of all levels (license, master and doctoral) of faculties in the country and abroad. We want to offer the participants the opportunity to present their scientific works in the following areas: Social Sciences, Economic Sciences, Legal Sciences, Humanities, Education Sciences, Engineering, Medicine and Sport. This journal provides students the opportunity to create and/or to improve their abilities to write scientific papers. So each appearance (two appearances per year at which we can add supplements) contains a number of papers written by students, masters and doctoral from the faculties from the country or/and abroad. The journal promotes original studies contributing to the progress of knowledge and it is motivated by the need to address issues of theory and practice in the areas mentioned above

HyperDE: An Adaptive Hyper-Heuristic for Global Optimization

In this paper, a novel global optimization approach in the form of an adaptive hyper-heuristic, namely HyperDE, is proposed. As the naming suggests, the method is based on the Differential Evolution (DE) heuristic, which is a well-established optimization approach inspired by the theory of evolution. Additionally, two other similar approaches are introduced for comparison and validation, HyperSSA and HyperBES, based on Sparrow Search Algorithm (SSA) and Bald Eagle Search (BES), respectively. The method consists of a genetic algorithm that is adopted as a high-level online learning mechanism, in order to adjust the hyper-parameters and facilitate the collaboration of a homogeneous set of low-level heuristics with the intent of maximizing the performance of the search for global optima. Comparison with the heuristics that the proposed methodologies are based on, along with other state-of-the-art methods, is favorable

Variability of ex-vivo stimulated T-cells secretory profile in healthy subjects

Peripheral blood lymphocytes (PBL) are able to synthesize various cytokines that play key roles in the immune response and intercellular signaling. Since alterations in cytokine production and/or activity occur in many pathological processes, the study of cytokine synthetic capacity of PBL is a valuable tool for assessing the immune profile. In this paper, we aimed to investigate the variability of interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-α) and interferon gamma (IFN-γ) synthetic capacity of CD4+/CD8+ T-cells stimulated ex-vivo in healthy subjects, by means of a commercial intracellular cytokine staining (ICS) protocol. Peripheral blood mononuclear cells were isolated from 16 healthy subjects by Ficoll gradient centrifugation and activated ex-vivo with PMA/Ionomycin/Brefeldin-A for 4 hours. Activated PBL were surface-stained for CD3/CD4/CD8, fixed and permeabilized. ICS was performed using anti-human IL-2/TNF-α/IFN-γ and samples were analyzed on a BD-FACSAria-III flow cytometer. We recorded high post-isolation and post-activation mean viabilities: 82.1% and 82.4% respectively, p=0.84. Both CD4+/CD8+ subpopulations were found to partially produce each of the three cytokines, but in different proportions. On average, a significantly greater percentage of CD4+ cells was shown to produce IL-2 and TNF-α, compared with CD8+ cells (61.5%+/-5.8 vs. 25%+/-5.6 and 26.9%+/-11 vs. 7.5%+/-3.3 respectively, p---lt---0.0001 for both). Contrarily, IFN-γ was produced by a higher proportion of CD8+ cells (8.4%+/-3.9 vs. 6.8%+/-3.2, p=0.01). These results show that the employed ICS protocol elicits a satisfactory and consistent cytokine response from PBL of healthy subjects. The collected data may be used to outline a preliminary reference range for future studies on both healthy/pathological subjects

Three-Axis Level with WiFi Connection

The Three-Axial Level (TAL) device measures the angular inclination around the three axes of the orthogonal system. It consists of a tripleaxis magnetometer sensor with I2C transmission and a NodeMCU V3 development board with WiFi module integrated. The device processes data from sensor, displays it on its screen and also transmits the angular values to various PADs (Portable Access Device). The experimental testing confirmed the initial expectation, showing the properly on-site operation of the designed device. This device is useful in the supervising process to avoid perturbing the worker that performs the leveling operation or when the working place is hard to reach

Imagistic evaluation of matrix bone interface

The problematic elements of bone regenerative materials are represented by their quality control methods. The defects repaired by bone grafting material were evaluated by en face optical coherence tomography and by synchrotron radiation micro-CT. The images obtained by efOCT show defects in some of the investigated samples, at the bone interface with different osteoconductive bone substitutes and we were able to detect gaps as small as 50 μm. After the common synchrotron radiation micro-CT investigations, the slides were reconstructed and the 3D model was obtained. Along with the possibility of navigating inside the structure, one big advantage of this technique was pointed out: the remaining regenerative materials can be separated from the normal bone and the new bone can be visualized. Optical coherence tomography can be performed in vivo and can provide a qualitative and quantitative evaluation of the bone augmentation procedure. © 2014 Copyright SPIE

Osteogenic potential of bovine bone graft in combination with laser photobiomodulation: an ex-vivo assessment in Wistar rats by cross-linked studies based on synchrotron microtomography and histology

Background: Alveolar bone defects are usually the main concern when planning implant treatments for appropriate oral rehabilitation of patients. To improve local conditions and achieve implant treatments, there are several methods used for increasing bone volume. among which One of the most successful, versatile, and effective is considered guided bone regeneration. The aim of this demonstrative study was to propose an innovative analysis protocol for the evaluation of the effect of photobiomodulation on bone regeneration process, using rat calvarial defects of 5 mm in diameter, filled with xenograft, covered with collagen membrane, and then exposed to laser radiation. Methods: The animals were sacrificed at different points in time (i.e., after 14, 21, and 30 days). Samples of identical dimensions were harvested in order to compare the results obtained after different periods of healing. The analysis was performed by cross-linkinging the information obtained using histology and high-resolution synchrotron-based tomography on the same samples. A comparison has been made with both negative control (NC) groups (with a bone defect which was left for spontaneous healing), and positive control (PC) groups (in which the bone defects were filled with xenografts and collagen membrane without receiving laser treatment). Results: We demonstrated that using photobiomodulation provides a better healing effect than when receiving only the support of the biomaterial. This effect has been evident for short times treatments, i.e. during the first 14 days after surgery. Conclusion: The proposed analysis protocol has been effective in detecting the presence of higher quantities of bone volumes under remodeling after photobiomodulation with respect to the exclusive bone regeneration guided by the xenograft