Publications

Silver-exchanged zeolite-chitosan (AgZ-Ch) composites with varying AgZ content were prepared by solvent casting and modified under argon (Ar) plasma excited by a 13.56MHz radio frequency (RF) power source. Silver (Ag) was successfully incorporated in a natural zeolite host without losing its antibacterial activity against Escherichia coli and Staphylococcus aureus. The AgZ particles were incorporated into a chitosan matrix without making significant changes in the matrix structure. The composites also exhibited antibacterial sensitivity due to the inclusion of AgZ. Plasma treatment enhanced the surface wettability of polar and nonpolar test liquids of the composites. The average increase in total surface free energy after treatment was around 49% with the polar component having a significant change. Cytocompatibility tests showed at least 87% cell viability for pristine and plasma-treated composites comparable with supplemented RPMI as positive control. Hemocompatibility tests revealed that pristine composites does not promote hemolysis and the blood clotting ability is less than 10min. Coupled with antibacterial property, the fabricated composites have promising biomedical applications.

Urbanization has become a significant driver of aquaculture in the rapidly expanding cities of the global South. Using a case study of Laguna Lake and Metro Manila in the Philippines, this paper disaggregates the urban as a driver of aquaculture, and examines the social relations that structure urban-oriented aquaculture. It integrates access analysis with the value chain heuristic to identify how urbanization shapes domestic aquaculture value chains, and to map access mechanisms for firms and actors engaged in these chains. Macro-level urban processes drive aquaculture in at least four ways: as a source of demand for fish, as a source of input and capital flows, as a set of activities that transforms sites of aquaculture production, and as a sociocultural discourse. Micro-level mapping of access in the urban value chains shows a multitude of actors who derive benefits that range from direct participation in fish production and exchange to the indirect consumption benefits associated with lower-priced fish. Benefit and access mechanisms are unevenly distributed across the chain, and are configured and reinforced by social relations tied to place-based institutional contexts. Access analysis of urban value chains within the framework of urban drivers presents a means to evaluate the sustainability, poverty alleviation and development goals of aquaculture amid increasing urbanization.

Kaakibat ng binubuong UP Monolingguwal na Diksiyonaryong Filipino (UP MDF) ang pangangalap ng korpus ng wikang Filipino kapwa sa anyong pasalita at pasulat. Ang naturang korpus ang magsisilbing batayan sa pagpili ng mga salitang bubuo sa leksikograpikong akda, maging sa paglalarawan ng gramatika ng kontemporaryong gamit ng wikang pambansa. Pagtutuunan ng pansin ang pamamaraang ortograpiko ng mga pasulat na tekstong nakapaloob sa pasulat na korpus ng Filipino, partikular ang pagkakabit ng reduplicative affix C1(C2)V1- at ang pagbaybay ng mga salitang may <s(i)yon> at <s(i)ya>. Ihahambing ito sa mga pamantayang ipinatutupad ng Komisyon sa Wikang Filipino (KWF), na siyang pangunahing nagtatakda sa magiging anyo ng mga hiniram na salita patungong Filipino. Batay sa datos na nakalap, lumilitaw na bagaman may tiyak na tuntuning ipinatutupad ang KWF hinggil sa usapin ng pagbabaybay ng mga hiram na salita, makikita pa rin ang pagtaliwas dito kahit sa mga tekstong nailimbag na pambansa ang lawak ng sirkulasyon. Hindi maaaring isantabi ang mga kataliwasang ito sapagkat nilalayon ng UP MDF na ilarawan ang Filipino ayon sa mismong paggamit ng mga tagapagsalita nito sa kontemporaryong panahon, kung kaya, ang mga anyong may iba’t ibang paraan ng pagbaybay ay itinuturing na mga variant. Ang mga variant na may mataas na bilang ang gagamitin sa diksiyonaryo. Magkagayunpaman, kinakailangan pa ring isaalang-alang ang mga tuntunin ng KWF sa layuning makabuo ng batayan ang ortograpiyang Filipino, kung kaya inaasahan na ang diskurso hinggil sa paksang ito ay mananatili at magpapatuloy.

The UP Monolingguwal na Diksiyonaryong Filipino [UP Monolingual Filipino Dictionary] (UP MDF) is currently compiling a Filipino language corpus in written and spoken forms. This corpus will be the basis of words that will be chosen as part of the lexicographic work, as well as the description of the grammatical structure of the contemporary use of the national language. This paper focuses on the orthographic systems of the published texts included in the written corpus of Filipino, particularly the forms that are derived using the reduplicative affix C1(C2)V1- and the spelling or respelling of forms with <s(i)yon> and <s(i)ya>. The results of the description of these orthographic processes are compared with the standardization rules of the Komisyon sa Wikang Filipino [Commission on the Filipino Language] (KWF), the primary state language agency that assigns the written forms of borrowed terms in Filipino. From the data collected, it appears that while the KWF has already come up with definitive rules with regard to the spelling of borrowed lexical items, there have been a number of instances that these rules have been disregarded as seen from the materials that were published for national circulation and were used for the Filipino language corpus. These forms that deviate from the KWF rules, however, cannot be dismissed since the goal of the UP MDF is to describe the current use of Filipino by its speakers, hence, the forms that are spelled differently are considered variants and the word with the higher frequency count becomes the primary entry in the dictionary. Neverthless, there should be a consideration of the orthographic rules implemented by the KWF as a means of standardization such that discussions on the matter are expected to continue.

The essay inquires a general question: what is the relationship of theater and human rights? A preliminary reflection is provided using the different activities staged at the Cultural Center of the Philippines (CCP) on the occasion of Pista Rizalina (Fiesta Rizalina) in September 2017. The festival was named after Rizalina Ilagan, a student activist-artist abducted by the military during the Martial Law era under President Ferdinand E. Marcos. To date, Ilagan’s body has not been found. The festival is a commemoration of the victims of human rights violations encountered by thousands of Filipinos since the Martial Law era of Marcos. In the end, it is argued that performing human rights at the CCP is a tool to transmit traumatic experiences for the understanding of those who did not suffer violence, oppression and tyranny (i.e. today’s younger generation). The relationship of theatre and human rights is asserted to be a rehearsal for a community where the other is encountered with care and responsibility.

A green, dry, and energy-efficient method for the fabrication of silver-zeolite (AgZ) composite via 13.56MHz radio-frequency plasma reduction is demonstrated. Impregnation by soaking and ion-exchange deposition were performed to load the silver ions (Ag+) into the sodium-zeolite samples. Characterization was performed by optical emission spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analyses. Results indicate the successful reduction of Ag+ to its metallic state on the surface of the zeolite with a mean diameter of 165nm. This plasma-induced reduction technique opens possibilities in several areas including catalysis, adsorption, water treatment, and medicine.

This chapter explores how urban political ecological approaches to nature-society relations can illuminate understandings of dynamic urbanization in Southeast Asia. It argues that environmental issues and challenges of the 21st-century city can be enriched through a serious engagement with urban political ecology themes, concepts and perspectives. The chapter provides a survey of the key themes and metaphors of urban political ecology and discusses two theoretical interventions where case studies of cities in Southeast Asia may provide empirical contributions. It provides empirical discussions of two moments in the urbanization of nature – everyday city-making and urban resource frontier production – to illustrate analytical merits of urban political ecological thinking using the Philippine case study of Metro Manila and nearby Laguna Lake. The chapter also explores urban political ecology approaches to examine the urbanization of nature in Metro Manila, a Southeast Asian megacity of more than 12 million people.

This essay is a preliminary discussion of the palo-palo, a cultural performance of the Ivatan community in the Batanes group of islands in northernmost Philippines where performers strike “opponents’s” sticks to reenact a battle of two opposing camps. The first part is a descriptive narrative of the palo-palo performance. The second part is a preliminary analysis and theorization of the palo-palo’s origin by arguing that the performance could have been based on and/or inspired by the komedya, a Philippine traditional theatre form introduced by the Spaniards during colonization which has roots in the socio-historical conflict of the Christians and the Muslims in the Iberian Peninsula in Southwest Europe. Generally, the localization of the form is argued to be paradoxically an embrace and repudiation of the foreign.

We postulate a spatiotemporal multilevel model and estimate using forward search algorithm and MLE imbedded into the backfitting algorithm. Forward search algorithm ensures robustness of the estimates by filtering the effect of temporary structural changes in the estimation of the group-level covariates, the individual-level covariates and spatial parameters. Backfitting algorithm provides computational efficiency of estimation procedure assuming an additive model. Simulation studies show that estimates are robust even in the presence of structural changes induced for example by epidemic outbreak. The model also produced robust estimates even for small sample and short time series common in epidemiological settings. 

We propose a method that integrates bootstrap into the forward search algorithm in the construction of robust confidence intervals for elements of the eigenvectors of the correlation matrix in the presence of outliers. Coverage probability of the bootstrap simultaneous confidence intervals was compared to the coverage probabilities of regular asymptotic confidence region and asymptotic confidence region based on the minimum covariance determinant (MCD) approach through a simulation study. The method produced more stable coverage probabilities for datasets with or without outliers and across several sample sizes compared to approaches based on asymptotic confidence regions.

During strong earthquakes, reinforced concrete (RC) structures experience cyclic lateral loads that result to degradation in load-carrying capacity, and failure of columns in shear and/or flexure. This study presents a simple hysteretic hinge model that may be used in displacement-based analysis of RC columns, classified as flexure critical, shear critical, and shear-flexure critical, subjected to cyclic loads. The proposed hinge model made up of zero-length nonlinear springs can simulate the hysteretic behavior of reinforced concrete material in axial, shear, and flexure. The nonlinear parameters of the springs were derived from geometric and material properties of the column and estimated using Response-2000 software. Pushover analysis and response to cyclic loading were performed using the Open System for Earthquake Engineering Simulation (OpenSees) program and validated by comparing the force-displacement response of select forty-three RC columns available in the PEER Structural Performance Database. Results show that for the six rectangular columns, the numerical experiments using the proposed hinge model and the actual force-displacement curves gave R- squared values greater than 0.80 signifying good agreement of results. Therefore, it was concluded that the model can reasonably replicate nonlinear behavior of shear-, shear-flexure, and flexure-critical columns subjected to cyclic loading and, therefore, may be used to assess performance of actual RC columns.

Keywords—hinge model, reinforced concrete, performance assessment, OpenSees, column