The influence of leaf characteristics on epiphyllic cover : a test of hypotheses with artificial leaves

Studies of epiphyll ecology have been hindered by the biochemical and morphological variability of the leaf substrate. The use of artificial (plastic ribbon tape) leaves solved that problem in a study done at the Braulio Carrillo National Park, Costa Rica. It showed that after nine months of field exposure, relative epiphyll cover was similar in five leaf shapes and two sizes. Driptips do not affect epiphyll cover, which was four times higher under a clearing than in the shaded understory, for all leaf shapes and sizes

Cotton Gravity: the cosmological constant as spatial curvature

We derive Friedman-Lemaitre-Robertson-Walker (FLRW) models as non-trivial solutions of "Cotton Gravity" (CG), a recently proposed gravity theory alternative to General Relativity (GR) based on the Cotton tensor. Using an equivalent formulation, we show that CG leads to FLRW models with a modified expression for spatial curvature in terms of the Ricci scalar of hypersurfaces orthonormal to the 4-velocity. Considering models compatible with a well posed initial value formulation leads to operationally the same FLRW models in GR, but endowed with a precise covariant characterization of the positive/negative cosmological constant as the case with constant negative/positive spatial curvature. Under CG, the $\Lambda$CDM model becomes the unique FLRW dust model with constant negative spatial curvature.Comment: 3 pages. Important corrections to previous version

Phenomenologizing the Leadership Practices of the Selected School Heads in the Philippines

Educational leadership has been one of the interesting arguments of many academic researchers over the years.  School heads have significant tasks to fulfill as they are responsible for the entire operation of the school as instructional and organizational leaders. In Catholic institutions, school heads are also accountable for the integral formation of the students, as well as the spiritual well-being of faculty and staff, parents and the stakeholder.  Most often, they are challenged by various obligations and they need to have strong spirituality in their leadership practices. This qualitative study attempted to describe the leadership practices of a select group of heads of schools  run  by the Franciscan Sisters of the Sacred Hearts in the Philippines as basis for a proposed leadership formation framework. Thirty  (30)  heads of  schools participated in the study.  Among them,  six (6) were Principals, six (6) were assistant principals, twelve (12) were academic coordinators and six (6) were heads of different offices. They underwent semi-structured depth interviews.  The findings formed  “The Whirl of Christ-Centred Leadership Model for  Heads of Schools”describes the common practices  and the critical instances which make the onset experience, and the value engagements that are observed in the institutions. The findings of this study provides valuable inputs to help  school heads to become more inclined and spiritually empowered to influence people, work collaboratively that may result to a progressive and smooth working environment.  

Improving reliability estimation in cognitive diagnosis modeling

Cognitive diagnosis models (CDMs) are used in educational, clinical, or personnel selection settings to classify respondents with respect to discrete attributes, identifying strengths and needs, and thus allowing to provide tailored training/treatment. As in any assessment, an accurate reliability estimation is crucial for valid score interpretations. In this sense, most CDM reliability indices are based on the posterior probabilities of the estimated attribute profiles. These posteriors are traditionally computed using point estimates for the model parameters as approximations to their populational values. If the uncertainty around these parameters is unaccounted for, the posteriors may be overly peaked, deriving into overestimated reliabilities. This article presents a multiple imputation (MI) procedure to integrate out the model parameters in the estimation of the posterior distributions, thus correcting the reliability estimation. A simulation study was conducted to compare the MI procedure with the traditional reliability estimation. Five factors were manipulated: the attribute structure, the CDM model (DINA and G-DINA), test length, sample size, and item quality. Additionally, an illustration using the Examination for the Certificate of Proficiency in English data was analyzed. The effect of sample size was studied by sampling subsets of subjects from the complete data. In both studies, the traditional reliability estimation systematically provided overestimated reliabilities, whereas the MI procedure offered more accurate results. Accordingly, practitioners in small educational or clinical settings should be aware that the reliability estimation using model parameter point estimates may be positively biased. R codes for the MI procedure are made availableOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work has been funded by the Community of Madrid through the Pluriannual Agreement with the Universidad de Universidad Autónoma de Madrid in its Programa de Estímulo a la Investigación de Jóvenes Doctores (Reference SI3/ PJI/2021-00258), and by the Spanish Ministry of Science and Innovation (FPI BES-2016-077814