Blind Multiclass Ensemble Classification

The rising interest in pattern recognition and data analytics has spurred the development of innovative machine learning algorithms and tools. However, as each algorithm has its strengths and limitations, one is motivated to judiciously fuse multiple algorithms in order to find the "best" performing one, for a given dataset. Ensemble learning aims at such high-performance meta-algorithm, by combining the outputs from multiple algorithms. The present work introduces a blind scheme for learning from ensembles of classifiers, using a moment matching method that leverages joint tensor and matrix factorization. Blind refers to the combiner who has no knowledge of the ground-truth labels that each classifier has been trained on. A rigorous performance analysis is derived and the proposed scheme is evaluated on synthetic and real datasets.Comment: To appear in IEEE Transactions in Signal Processin

Matrix completion and extrapolation via kernel regression

Matrix completion and extrapolation (MCEX) are dealt with here over reproducing kernel Hilbert spaces (RKHSs) in order to account for prior information present in the available data. Aiming at a faster and low-complexity solver, the task is formulated as a kernel ridge regression. The resultant MCEX algorithm can also afford online implementation, while the class of kernel functions also encompasses several existing approaches to MC with prior information. Numerical tests on synthetic and real datasets show that the novel approach performs faster than widespread methods such as alternating least squares (ALS) or stochastic gradient descent (SGD), and that the recovery error is reduced, especially when dealing with noisy data

Circumstellar effects on the Rb abundances in O-rich AGB stars

For the first time we explore the circumstellar effects on the Rb (and Zr) abundance determination in O-rich asymptotic giant branch (AGB) stars by considering the presence of a gaseous circumstellar envelope with a radial wind. A modified version of the spectral synthesis code Turbospectrum was used to deal with extended atmosphere models and velocity fields. The Rb and Zr abundances were determined from the resonant 7800A Rb I line and the 6474A ZrO bandhead, respectively, in five representative O-rich AGB stars with different expansion velocity and metallicity. By using our new dynamical models, the Rb I line profile (photospheric and circumstellar components) is very well reproduced. Interestingly, the derived Rb abundances are much lower (by 1-2 dex) in those O-rich AGB stars showing the higher circumstellar expansion velocities. The Zr abundances, however, remain close to the solar values. The Rb abundances and Rb/Zr ratios derived here significantly alleviate the problem of the present mismatch between the observations of intermediate-mass (4-8 solar masses) Rb-rich AGB stars and the AGB nucleosynthesis theoretical predictions.Comment: Accepted for publication in Astronomy & Astrophysics Letters (7 pages, 5 figures, and 2 tables); final version (language corrected

Enhancing environmental education through community service learning: a qualitative exploration of curriculum integration

This study explored the integration of environmental education into the curriculum through community service learning (CSL) in the Philippines. A review of related literature and DepEd orders related to environmental education curriculum integration was conducted to provide a comprehensive overview of the topic. The study found that there is a growing interest in integrating environmental education into the curriculum in the Philippines, and that community service learning is a promising approach for achieving this goal. However, the implementation of DepEd orders related to environmental education curriculum integration remains inconsistent and faces various challenges. The review highlighted the benefits of environmental education, such as fostering environmental awareness, promoting positive attitudes and behaviors towards the environment, and providing students with the knowledge and skills necessary to become responsible and engaged environmental citizens. The review also identified the benefits of community service learning, including promoting academic learning, personal and social development, and civic engagement. The study emphasized the need for further empirical research to explore the actual implementation and effectiveness of DepEd orders related to environmental education curriculum integration, investigate the role of community partnerships, and explore the impact of environmental education on student outcomes beyond just environmental knowledge and attitudes. Overall, the study suggests that environmental education and community service learning have the potential to enhance the curriculum and promote responsible and engaged environmental citizenship in the Philippines

Designing the school physical plant and facilities: An instructional material for Technical Drafting 10

The purpose of this study was to evaluate the physical plant status of the DepEd Toledo City Division in 2018 in order to suggest a development strategy. With the use of various statistical approaches, the researcher adopted a descriptive nominative approach. This is done to ascertain the conditions, practices, and scenarios that are typical of the research setting to find out what the superintendent of the Schools Division, the chiefs of the Curriculum Implementation Division, the School Governance and Operations Division, the Division Engineer, the Division Risk Reduction Management Project Development Officer, the section heads, the office staff, the school heads, and the teachers think about the various parts of the division’s physical infrastructure. The first section, Plan A, contains the proposed five-year development plan for the physical plant and facilities of the DepEd Toledo City Division. This plan includes recommendations for improving the physical plant of the school and its facilities in order to accommodate the division’s growing staff and to address any problems with those facilities that have been identified. The division’s current maintenance program and practices are improved in the second part of Plan B, which is the presentation of an enhanced maintenance plan for the facilities of DepEd Toledo City. This will help to delay early deterioration of the division’s facilities and structure. For technical drafting training, the proposed design orientation model of the physical plant and facilities can be used. Students studying technical drafting are permitted to utilize the design as a resource for their coursework

Morphology and palaeoecology of a new edrioblastoid from the Furongian of China

A new edrioblastoid Cambroblastus guolensis is described from the Furongian (late Cambrian) Sandu Formation (South China). This represents the second occurrence of a Cambrian edrioblastoid, and the first ever reported from Asia, extending the palaeogeographic range of this very rare echinoderm grade. Surprisingly it preserves a complete stem and a distal holdfast suggesting edrioblastoids were hard substrate attachers living in soft bottom quiet environments

Rubidium and zirconium abundances in massive Galactic asymptotic giant branch stars revisited

Luminous Galactic OH/IR stars have been identified as massive (>4-5 M_s) AGB stars experiencing HBB and Li production. Their Rb abundances and [Rb/Zr] ratios derived from hydrostatic model atmospheres, are significantly higher than predictions from AGB nucleosynthesis models, posing a problem to our understanding of AGB evolution and nucleosynthesis. We report new Rb and Zr abundances in the full sample of massive Galactic AGB stars, previously studied with hydrostatic models, by using more realistic extended model atmospheres. We use a modified version of the spectral synthesis code Turbospectrum and consider the presence of a circumstellar envelope and radial wind. The Rb and Zr abundances are determined from the 7800 A Rb I resonant line and the 6474 A ZrO bandhead, respectively, and we explore the sensitivity of the derived abundances to variations of the stellar (Teff) and wind (M_loss, beta and vexp) parameters in the extended models. The Rb and Zr abundances derived from the best spectral fits are compared with the most recent AGB nucleosynthesis theoretical models. The new Rb abundances are much lower (even 1-2 dex) than those derived with the hydrostatic models, while the Zr abundances are similar. The Rb I line profile and Rb abundance are very sensitive to the M_loss rate but much less sensitive to variations of the wind velocity-law and the vexp(OH). We confirm the earlier preliminary results based on a smaller sample of massive O-rich AGB stars, that the use of extended atmosphere models can solve the discrepancy between the AGB nucleosynthesis theoretical models and the observations of Galactic massive AGB stars. The Rb abundances, however, are still strongly dependent of the M_loss, which is unknown in these AGB stars. Accurate M_loss rates in these massive Galactic AGB stars are needed in order to break the models degeneracy and get reliable Rb abundances in these stars.Comment: Accepted for publication in A&A, 14 pages, 12 figures, 4 table

Clear evidence for the presence of second-generation asymptotic giant branch stars in metal-poor Galactic globular clusters

Galactic globular clusters (GCs) are known to host multiple stellar populations: a first generation with a chemical pattern typical of halo field stars and a second generation (SG) enriched in Na and Al and depleted in O and Mg. Both stellar generations are found at different evolutionary stages (e.g., the main-sequence turnoff, the subgiant branch, and the red giant branch). The non detection of SG asymptotic giant branch (AGB) stars in several metal-poor ([Fe/H] < -1) GCs suggests that not all SG stars ascend the AGB phase, and that failed AGB stars may be very common in metal-poor GCs. This observation represents a serious problem for stellar evolution and GC formation/evolution theories. We report fourteen SG-AGB stars in four metal-poor GCs (M 13, M 5, M 3, and M 2) with different observational properties: horizontal branch (HB) morphology, metallicity, and age. By combining the H-band Al abundances obtained by the APOGEE survey with ground-based optical photometry, we identify SG Al-rich AGB stars in these four GCs and show that Al-rich RGB/AGB GC stars should be Na-rich. Our observations provide strong support for present, standard stellar models, i.e., without including a strong mass-loss efficiency, for low-mass HB stars. In fact, current empirical evidence is in agreement with the predicted distribution of FG and and SG stars during the He-burning stages based on these standard stellar models.Comment: Accepted for publication in The Astrophysical Journal Letters (16 pages, 4 figures, and 1 table

Apparent returns on training in French firms: impacts on productivity and wages

We estimate the productivity- and wage-returns to firm-provided training in a panel of French Firms. We find positive and significant returns to training on productivity. For instance, an increase in training intensity by 150 Euros per worker increases a firms labor productivity by 0.4 %. Moreover, firms benefit from providing training to their workers, since they keep most of the gain from training. Indeed, the wage increase following training is less than half of the productivity increase. However, the study only measures apparent returns. Even if it tries to control short-run simultaneity biases, it does not separate between the direct effects of training and the effect of factors that generally accompany or motivate training in the medium and the long run, such as technological or organisational changes.On-the-job Training ; Productivity ; Wages