University of the Philippines at Mindanao
Davao City, Philippines
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Acosta J.E.,University of the Philippines at Mindanao | Oguis G.K.R.,University of the Philippines at Mindanao
37th Asian Conference on Remote Sensing, ACRS 2016 | Year: 2016

Rainfall and surface water runoff facilitates the transport of contaminants such as sediments, nutrients, and pesticides, depending upon the area involved. With the use of GIS tools such as digital terrain analysis techniques on high resolution DEMs derived from LiDAR, landscapes that are hydrologically connected, either by river networks or simply overland runoff drainages, can be identified with a degree of significance. The identified critical areas are classified: ravines, which are active erosional features that contribute to significant amount of sediments nearby waterways; artificially drained upland depressions, which can be formerly wetlands or accumulate surface water; and riparian areas, which are areas that have greater potential of transporting contaminants during storm events. Actual field validation enabled the calibration of thresholds levels for more accurate classification and identification of critical areas. The result of the study will provide additional input for watershed management practices.

Del Mundo D.M.N.,Suranaree University of Technology | Del Mundo D.M.N.,University of the Philippines at Mindanao | Sutheerawattananonda M.,Suranaree University of Technology
Water Research | Year: 2017

Fat, oil, and grease (FOG) deposit, in the form of calcium soap, was found to cause sanitary sewer overflows due to its adhesion on pipe walls. To address this problem, laboratory-prepared calcium soaps have been used to investigate the formation mechanisms of FOG deposits. However, the fats and oils previously utilized were limited and some soap characteristics were not examined. This research attempted to probe through the properties of calcium soaps prepared from calcium chloride and the fats and oils of chicken, pork, palm olein, soybean, olive, and coconut to further understand FOG formation and stability. Results revealed that FOG deposits may occur as smooth, paste-like material or coarse, semi-solid substance depending on their exposure to excess fat/oil and calcium. The smooth soaps with more excess fat/oil demonstrated high apparent viscosity and consistency index, while the coarse soaps with large levels of calcium signified higher melting endset. Moreover, a soap microstructure showing evident networks and lesser void area displayed higher heat and rheological stability, respectively. Overall, fats and oils with higher oleic to palmitic acid ratio such as palm olein oil, olive oil, chicken fat, and pork fat produced soaps with greater yield and degree of saponification. Hence, establishments and authorities should be alert in managing and monitoring these wastes. On the other hand, soybean oil high in linoleic acid and coconut oil high in lauric acid do not pose an immediate threat to the sewer system since they only produced soaps in small quantity. However, their soaps showed high melting endset which could pose a serious effect when accumulated at large amount. On the whole, the fatty acid profile of fats and oils, the presence of excess fat/oil, and calcium content mainly dictate the appearance, melting, rheology, and microstructure of calcium soaps. Their distinct properties can be used as criteria in predicting the condition and stability of FOG deposits. © 2017 Elsevier Ltd

Purcell S.W.,Southern Cross University of Australia | Polidoro B.A.,Old Dominion University | Polidoro B.A.,Arizona State University | Hamel J.-F.,Philips | And 2 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2014

Extinction risk has been linked to biological and anthropogenic variables. Prediction of extinction risk in valuable fauna may not followmainstream drivers when species are exploited for international markets. We use results from an International Union for Conservation of Nature Red List assessment of extinction risk in all 377 known species of sea cucumber within the order Aspidochirotida, many of which are exploited worldwide as luxury seafood for Asian markets. Extinction risk was primarily driven by high market value, compounded by accessibility and familiarity (well known) in the marketplace. Extinction risk in marine animals often relates closely to body size and small geographical range but our study shows a clear exception. Conservation must not lose sight of common species, especially those of high value. Greater human population density and poorer economies in the geographical ranges of endangered species illustrate that anthropogenic variables can also predict extinction risks in marine animals. Local-level regulatory measuresmust prevent opportunistic exploitation of high-value species. Trade agreements, for example CITES, may aid conservation but will depend on international technical support to low-income tropical countries. The high proportion of data deficient species also stresses a need for research on the ecology and population demographics of unglamorous invertebrates. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Nuneza O.M.,MSU Iligan Institute of Technology | Ates F.B.,University of the Philippines at Mindanao | Alicante A.A.,Mindanao State University
Biodiversity and Conservation | Year: 2010

Mt. Malindang is one of the upland ranges where biodiversity has been severely threatened due to forest loss. Fieldwork was conducted from October 2003 to December 2004 in 14 sampling sites from an elevation of 120 to over 1,700 m above sea level to assess the distribution of endemic and threatened herpetofaunal species. Twenty-six species of amphibians and 33 species of reptiles were observed for all sampling sites. The level of endemism for amphibians was 42% where 7 of the 11 recorded species are found only in Mindanao. Nine species were in the threatened category, 8 vulnerable and 1 endangered. For the reptiles, 48% endemicity was observed. No threatened species was found. Field observations show that the major threat to the herpetofauna is habitat destruction, particularly the conversion of the forest to agricultural farms by the local people. It was also observed that endemic and threatened species were distributed in high elevation sites (submontane, dipterocarp, almaciga, and montane forests). Despite habitat loss in Mt. Malindang, 18% of the recorded herpetofaunal species recorded in the Philippines were found in Mt. Malindang, indicating the conservation importance of this mountain range. © Springer Science+Business Media B.V. 2009.

Dacera D.D.,University of the Philippines at Mindanao | Babel S.,Thammasat University
Soil and Sediment Contamination | Year: 2013

Metal fractionation studies on metals in sludge are usually done on dried sludge. Although there are advantages in this form of sludge, it is possible that fractionation of metals in sludge may be influenced by the drying process, which consequently affects mobility of metals at disposal. In this study, sequential chemical extraction was done to assess the effect of drying on fractionation of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn) on wet and dewatered (air-dried and oven-dried) anaerobically digested sludge samples in Bangkok, Thailand. Results revealed an insignificant difference in the fractionation profile of metals for both wet and dewatered sludge. The higher percentage of residual fraction for Cu and oxidizable fraction for Zn in the wet sludge, however, makes this form more suitable for direct land application. In the case of oven-dried and air-dried sludge, the forms of some metals (e.g., Pb and Zn) seem to vary significantly as the sludge is oven-dried, with Pb decreasing its residual phase by 15%, and Zn increasing in oxidizable phase by 41%. The results seem to indicate that drying affects bioavailability of metals in sludge and air-drying seems to favor sludge for land application. © 2013 Copyright Taylor and Francis Group, LLC.

Holmes W.R.,University of Melbourne | Holmes W.R.,University of California at Irvine | Mata M.A.,University of British Columbia | Mata M.A.,University of the Philippines at Mindanao | Edelstein-Keshet L.,University of British Columbia
Biophysical Journal | Year: 2015

Diffusion and interaction of molecular regulators in cells is often modeled using reaction-diffusion partial differential equations. Analysis of such models and exploration of their parameter space is challenging, particularly for systems of high dimensionality. Here, we present a relatively simple and straightforward analysis, the local perturbation analysis, that reveals how parameter variations affect model behavior. This computational tool, which greatly aids exploration of the behavior of a model, exploits a structural feature common to many cellular regulatory systems: regulators are typically either bound to a membrane or freely diffusing in the interior of the cell. Using well-documented, readily available bifurcation software, the local perturbation analysis tracks the approximate early evolution of an arbitrarily large perturbation of a homogeneous steady state. In doing so, it provides a bifurcation diagram that concisely describes various regimes of the model's behavior, reducing the need for exhaustive simulations to explore parameter space. We explain the method and provide detailed step-by-step guides to its use and application. © 2015 Biophysical Society.

Fundador N.G.V.,University of Tokyo | Fundador N.G.V.,University of the Philippines at Mindanao | Enomoto-Rogers Y.,University of Tokyo | Takemura A.,University of Tokyo | Iwata T.,University of Tokyo
Carbohydrate Polymers | Year: 2012

Alkaline treatment of eucalyptus hardwood kraft pulp with 10% NaOH yielded 6-8% xylan. The acetylation of the extracted xylan was carried in DMAC/LiCl/pyridine system to obtain a series of xylan acetates with different degrees of substitution (DS). Structure elucidation of xylan and xylan acetate was obtained by 1H and 13C NMR spectroscopy and other homonuclear and heteronuclear 2D-NMR techniques. Inverse-gated 13C NMR was employed to determine the DS of xylan acetate. Furthermore, results also revealed equal reactivities at the C-2 and C-3 positions of xylan towards acetylation. Thermal stability, solubility behavior and nanofiber formation of xylan acetate were influenced by its DS values. The mechanical properties of xylan acetate propionate were also investigated. © 2011 Elsevier Ltd. All Rights Reserved.

Fundador N.G.V.,University of Tokyo | Fundador N.G.V.,University of the Philippines at Mindanao | Enomoto-Rogers Y.,University of Tokyo | Takemura A.,University of Tokyo | Iwata T.,University of Tokyo
Polymer Degradation and Stability | Year: 2013

Xylan esters of varying alkyl chain lengths (C2-C12) were screened for their effect on the crystallization of poly(l-lactic acid) (PLLA). Among the xylan esters, only xylan propionate (XylPr) and xylan butyrate (XylBu) exhibited a nucleating effect on PLLA during non-isothermal crystallization. Blending of 1% XylPr or XylBu with PLLA led to a decrease in the crystallization temperature (Tc) of PLLA from 125 °C to 96 or 97 °C, respectively. Similar results were also obtained for 0.1% blends of the same ester. Isothermal crystallization studies revealed that the PLLA blends exhibited faster crystallization rates, higher crystallinities and smaller spherulites than neat PLLA. Consequently, the PLLA blends possessed lower degrees of haze than neat PLLA and their thermal expansion values were also lower than that of neat PLLA when heated above their glass transition temperature (60 °C), indicating their resistance to heat deformation. The mechanism of nucleation was proposed based from the WAXD analysis results. © 2013 Elsevier Ltd. All rights reserved.

Digal L.N.,University of the Philippines at Mindanao
International Review of Retail, Distribution and Consumer Research | Year: 2015

The number of modern food retailers such as supermarkets and hypermarkets has increased considerably in the Philippines. However, participation of foreign retailers has been limited since opening the retail sector to foreign investment in March 2000 through Republic Act 8762. The rapid expansion of the sector came mostly from a few large domestic food retail chains. This paper aims to examine the market structure of the modern retail food sector particularly the dominance of the large domestic retailers and their implications on supply chains notably, on small-scale food retailers and producers. Results show that dominance of a few large domestic retailers has continued despite liberalization as indicated by high concentration ratios (CRs). While CRs initially reduced within 5 years after liberalization, they eventually increased through joint ventures and buy out of foreign retailers. These are expected to increase further with the proliferation of stand-alone stores and convenience stores under joint ventures with foreign retailers and strategic partnerships with other large retail and property development firms. There is some evidence of displacement of small traditional retailers and only a few small suppliers to supermarkets succeeded, despite efforts of the government and non-government organizations to help them access modern food retailers. It is suggested that the review and subsequent amendment of RA 8762 should be expedited and studies conducted to examine further the effects of the dominance of large food retailers in the chain including the possibility of market power in the output and input markets. © 2015 Taylor & Francis

Kobayashi V.,University of the Philippines at Mindanao
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

We describe a novel methodology that is applicable in the detection of emotions from speech signals. The methodology is useful if we can safely ignore sequence information since it constructs static feature vectors to represent a sequence of values; this is the case of the current application. In the initial feature extraction part, the speech signals are cut into 3 speech segments according to relative time interval process. The speech segments are processed and described using 988 acoustic features. Our proposed methodology consists of two steps. The first step constructs emotion models using principal component analysis and it computes distances of the observations to each emotion models. The distance values from the previous step are used to train a support vector machine classifier that can identify the affective content of a speech signal. We note that our method is not only applicable for speech signal, it can also be used to analyse other data of similar nature. The proposed method is tested using four emotional databases. Results showed competitive performance yielding an average accuracy of at least 80 % on three databases for the detection of basic types of emotion. © 2014 Springer International Publishing.

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