International Journal of Philippine Science and Technology ( formerly Philippine Science Letters )



ARTICLE

Adsorbate-induced demagnetization: borohydride on magnetic substrates

by Ryan Lacdao Arevalo, Mary Clare Sison Escaño, Allan Abraham Bustria Padama, and Hideaki Kasai

Elucidating the effect of different adsorbates on the magnetic properties of substrates has found useful applications in the design of magnetic devices. In this paper, we show through first principles calculations that the adsorption of borohydride on magnetic substrates (pure 3d or first row transition metals such as Cr, Mn, Fe, Co, and Ni and Au-3d metal alloys) induces the demagnetization of the substrate atoms that directly bind with borohydride. We note a forward shifting of the spin-up and backward shifting of the spin-down components of the metal d band, before and after the adsorption of borohydride, demagnetizing the substrate. The inclusion of spin-polarization in the calculation affects the adsorption energy of borohydride but not its adsorption structure and relative energies on different substrates. Large substrate demagnetization is noted for substrates that promote the strong adsorption of borohydride... Continue reading


Posted on August 11, 2016 in the International Journal of Philippine Science and Technology 2016 Volume 9 Issue Number 1 Page 10-14
WHITE PAPER

Knowledge-Based Development and Governance: Challenges and Recommendations to the Duterte Administration, 2016-2022

by University of the Philippines

Many developing countries have been beset by persistent problems of inequality and poverty. The Philippines is one of those countries. Its gross national income (GNI) per capita is now the lowest among the five original ASEAN member-countries (Indonesia, Malaysia, Philippines, Singapore, and Thailand). Its inequality and poverty metrics at 46 percent (Gini coefficient, 2012) and 25.2 percent (headcount, 2012), respectively, remain the highest relative to the four other ASEAN originals plus newcomer Vietnam. This situation has persisted despite the country’s economic growth during the current administration averaging 6.2 percent, the highest over the last four decades or so... Continue reading


Posted on July 29, 2016 in the International Journal of Philippine Science and Technology 2016 Volume 9 Issue Number 1 Page 1-9
SHORT COMMUNICATION

Relationship of agro-morphological traits to water use efficiency of irrigated lowland rice varieties under screenhouse condition

by Ace Mugssy L. Agustin and Nina M. Cadiz

Rice (Oryza sativa L.) is the only cereal food crop that grows in different hydrological conditions. As staple food in the Philippines, it is cultivated in different parts of the country from irrigated to rainfed lowland, upland, cool elevated, flood-prone, and saline ecosystems. Among these ecosystems, irrigated lowland has highest production, however its productivity is threatened by increasing water scarcity. Crop water use efficiency is widely used to evaluate productivity in terms of water use. However, currently, there are limited studies in this area particularly on the relationship of agro-morphological traits to water use efficiency which can be used by breeders to improve rice water use efficiency. Hence, this study aimed to identify the relationship of agro-morphological traits to biomass production, evapotranspiration, and water use efficiency of irrigated lowland rice varieties, and to identify growth phase and variety with highest water use efficiency. Three irrigated lowland rice varieties were grown in the pots with 40cm x 30cm (row x hill) planting distance under screenhouse condition. This was laid-out in split-plot in Randomized Complete Block Design with growth phase as main plot and variety as sub-plot, replicated three times. Based on the result, broad leaf contributed in decreasing evapotranspiration and increasing biomass and water use efficiency. Broad leaves have higher boundary layer and contribute to better covering of soil surface both of which reduce evapotranspiration, and contribute to higher light interception for higher biomass production, hence high water use efficiency. Other traits such as long leaf, high spikelet fertility, heavy grain, and early maturity also contributed to reduction of evapotranspiration and improvement of water use efficiency. Hence, these traits might have the potential to improve water use efficiency of irrigated lowland rice varieties. Among growth phases, reproductive phase had highest water use efficiency due to higher rate of increase in biomass and lower rate of increase in evapotranspiration than ripening phase. NSIC Rc202H with broadest leaves and lowest cumulative evapotranspiration had highest water use efficiency than NSIC Rc222 and PSB Rc18... Continue reading


Posted on December 4, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 78-81
SHORT COMMUNICATION

Assessment of bacterial species present in Pasig River and Marikina River soil using 16S rDNA phylogenetic analysis

by Maria Constancia O. Carrillo, Paul Kenny L. Ko, Arvin S. Marasigan, and Arlou Kristina J. Angeles

The Pasig River system, which includes its major tributaries, the Marikina, Taguig-Pateros, and San Juan Rivers, is the most important river system in Metro Manila. It is known to be heavily polluted due to the dumping of domestic, industrial and solid wastes. Identification of microbial species present in the riverbed may be used to assess water and soil quality, and can help in assessing the river’s capability of supporting other flora and fauna. In this study, 16S rRNA gene or 16S rDNA sequences obtained from community bacterial DNA extracted from riverbed soil of Napindan (an upstream site along the Pasig River) and Vargas (which is along the Marikina River) were used to obtain a snapshot of the types of bacteria populating these sites. The 16S rDNA sequences of amplicons produced in PCR with total DNA extracted from soil samples as template were used to build clone libraries. Four positive clones were identified from each site and were sequenced. BLAST analysis revealed that none of the contiguous sequences obtained had complete sequence similarity to any known cultured bacterial species. Using the classification output of the Ribosomal Database Project (RDP) Classifier and DECIPHER programs, 16S rDNA sequences of closely related species were collated and used to construct a neighbor-joining phylogenetic tree using MEGA6. Six out of the 8 cloned samples were found to belong to obligate anaerobe species, suggesting that these species live deep within the sediment layer and do not have access to dissolved oxygen. Three species were found to be associated with sulfate-reducing bacteria, which suggests an abundance of sulfur containing compounds in the riverbed. This is the first census report of the Pasig River microbial population using an approach that utilizes 16S rDNA sequences without culture nor isolation of bacteria. Further studies employing multiple composite samples and larger sample sizes are recommended for more comprehensive bacterial taxonomic profiles as well as evaluation of interactions between community members and bacterial response to environmental perturbations... Continue reading


Posted on November 14, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 73-77
REVIEW

Acceptability, nutritional, and potential health values of sweet sorghum [Sorghum bicolor (L.) Moench] coffee substitute

by Sheila F. Abacan, Wilma A. Hurtada, Erlinda I. Dizon, and Aimee Sheree A. Barrion

Utilization of sorghum to improve nutrition and health among Filipinos is limited due to insufficient information from research on the crop as a source of valuable nutrients and health promoting phytochemicals. The objective of this study was to develop an acceptable, nutritious, and healthful coffee substitute from sweet sorghum grains. The sweet sorghum coffee substitute (SSCS) was made by combining different roasting time of the grains (50, 60, and 70 min) at 226±5°C, powder to water ratio (16 g/250 mL-1, 24 g/250 mL-1), and brewing time (3 and 6 min). The 12 SSCS brewed samples were subjected to sensory evaluation composed of 55 untrained coffee drinker panelist. The most acceptable SSCS and the raw sorghum grain were analyzed for proximate composition, starch, amylose, dietary fiber, fatty acid profile, phytochemicals (total phenols, flavonoids, tannins) and antioxidant activity. The results showed that roasting time of the grains had a significant effect on the sensory characteristics and acceptability of the SSCS brew while powder to water ratio and brewing time have no effect. Roasting sweet sorghum grains for 70 min at 226±5°C and brewing using the powder to water ratio of 16 g/ 250 mL-1 for 3 min produced the most acceptable sample with characteristic dark brown color, aroma and flavor resembling “rice coffee”, and coffee-like bitterness. This study also revealed that SSCS could be a potential health and nutritious beverage as its powder provides energy from carbohydrates and protein, is low in fat particularly saturated fat, contains essential fatty acids, and has dietary fiber. Moreover, SSCS powder contains phytochemicals, such as phenols particularly flavonoids, which contribute to its high antioxidant activity. These findings suggest that, in general, SSCS could be a beneficial in preventing diseases involving oxidative stress and chronic diseases... Continue reading


Posted on November 1, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 68-72
REVIEW

Bacteriocins from Lactic Acid Bacteria: A Review of Biosynthesis, Mode of Action, Fermentative Production, Uses, and Prospects

by Rodney H. Perez, Maria Teresa M. Perez, and Francisco B. Elegado

Bacteriocins are antimicrobial peptides that help bacteria fight competing bacteria in microecological systems. Bacteriocins of lactic acid bacteria (LAB) have attracted much interest in recent years because of their properties that make them suitable as natural food preservatives against specific food pathogens, and as possible supplement to antibiotics against drug resistant bacterial strains. LAB bacteriocins are generally classified into the lantibiotics and non-lantibiotics, the latter divided into four sub-groups. To date, only nisin and to a lesser extent, pediocin are the commercially applied bacteriocins for food use. Clinical applications are still limited to animal health. One of the more exciting prospects on the use of bacteriocins is the possibility of subjecting them to bioengineering to either increase antimicrobial activity or further specify their target microorganism. The latter would make it less damaging to the natural gut microflora, which is a common drawback of conventional antibiotic therapy... Continue reading


Posted on October 30, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 61-67
ARTICLE

Copper-resistant, biofilm-forming bacteria for potential use in rehabilitation of copper-contaminated wastewater

by RB Opulencia, ME Bambase Jr., KMD Perdigon, RB Demafelis, AA Llamado, RAG Franco, RT Mogul, and AK Raymundo

Ninety bacterial isolates from copper-contaminated wastewater from a local semiconductor company were screened for resistance to varying concentrations of copper. Of the copper-resistant isolates, 49 produced biofilm at varying thickness on microtiter plate using Tryptic Soy Broth as substrate. Isolate T21 could tolerate up to 125 ppm copper and was provisionally identified as Bacillus megaterium based on comparative analysis of 16S rRNA sequences. Isolate T21 was immobilized as biofilm on a 30-liter fixed-bed upflow reactor using polyvinyl chloride corrugated pipe and Tryptic Soy Broth combined with alcohol distillery slop (75:25 v/v) as carrier and growth medium, respectively. When used to treat copper-containing wastewater effluent from a local semiconductor company, the immobilized biofilm reduced copper to as much as 65.95%, showing potential to clean up copper-contaminated wastewater... Continue reading


Posted on October 5, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 56-60
SHORT COMMUNICATION

Incidence and molecular detection of Salmonella enterica serogroups and spvC virulence gene in raw and processed meats from selected wet markets in Metro Manila, Philippines

by Shiela A. Soguilon-Del Rosario and Windell L. Rivera

A simple and specific detection method for Salmonella enterica was applied to determine its incidence in raw and processed meats purchased from selected wet markets in Metro Manila, Philippines. A total of 320 raw and processed meat samples were analysed for the presence of S. enterica and S. enterica possessing spvC gene of the virulence plasmid. Polymerase chain reaction (PCR) revealed that 30.63% (98/320) were positive for S. enterica and 2.81% (9/98) of S. enterica-positive samples were also positive for the spvC gene. S. enterica was identified from chicken samples (67.5%), ground pork (65%), beef (52.5%), sausage (longganisa) (25%), cured pork meat (tocino) (20%), burger patty (12.5%), and meatloaf (embotido) (2.5%). Positive samples were further analysed for O-serogrouping targeting S. enterica serogroups A, B, C1, C2, D, and E1. Our findings revealed that the raw and processed meats tested were contaminated with more than one serogroup in a sample. Samples were found positive for S. enterica serogroups E1 (78.57%), C1 (29.59%), C2 (20.41%), B (17.35%) and D (6.1%). No samples were found positive for S. enterica serogroup A. This is the first report on the use of multiplex PCR for the detection and characterization of S. enterica in raw and processed meats in the Philippines. Data on incidence of S. enterica and its serogroups found in raw and processed meats in selected Philippine wet markets gathered from this study can be used for further research on epidemiology and related topics... Continue reading


Posted on September 30, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 52-55
SHORT COMMUNICATION

Potential of Endophytic Fungi of Barnyard Grass Weed for Biological Control of the Rice Sheath Blight Pathogen, Rhizoctonia solani Kühn

by Dindo King M. Donayre and Teresita U. Dalisay

Endophytic fungi are group of microorganisms that colonize internal tissues of plants but do not cause any harm to their hosts. Although it has been reported that endophytic fungi from weeds have the potential as biological control agents against disease-causing pathogens of crops, the efficacy of those from barnyard grass weeds against sheath blight disease of rice caused by Rhizoctonia solani Kühn has not yet been studied. This study determined the potential of endophytic fungi of barnyard grass weed (Echinochloa glabrescens Munro ex Hook. f.) as biological control agents of R. solani and identified the most effective of these endophytic fungi... Continue reading


Posted on September 29, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 48-51
POP SCIENCE

Integrative Societal Resilience or 'One Resilience' Approach: Towards Optimal Health and Wellbeing

by Noel Lee J. Miranda

Emerging pandemic threats (EPT) are recognized as real challenges to health and global security. The technical, political, socio-economic, environmental and comprehensive security challenges posed by EPTs require holistic collaborative efforts- going beyond the health sector. Lack of preparedness is anticipated to result in massive socio-economic disruptions and loss of lives, as conveyed by the West African Ebola virus disease (EVD) outbreaks where the combination of spreading fear and uncertainty, and the imposition of movement restrictions and quarantine have heavily impacted on livelihood, business and essential services and economic activities, that have led to social devastation and unrest... Continue reading


Posted on September 19, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 44-47
SHORT COMMUNICATION

Green Synthesis of Bimetallic PdAg Nanowires as Catalysts for the Conversion of Toxic Pollutants

by Jose Isagani B. Janairo

The green synthesis of bimetallic PdAg nanowires which were created under ambient conditions and in the absence of any stabilizers and harsh reagents is herein reported. The straightforward synthesis involved a one-pot set-up containing only the HEPES buffer, metal salt and reductant. The PdAg nanowires were efficient catalysts toward the reduction of common and toxic nitrophenol pollutants. The nanowires exhibited high turnover frequency and were able to achieve total conversion of the starting material. The bimetallic materials were also superior catalysts relative to other materials reported in literature. Taken together, the method and material presented have the potential to be of great use and value to environmental catalysis... Continue reading


Posted on September 17, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 41-43
ARTICLE

Resilience to thermal stress of coral communities in Talim Bay, Lian, Batangas

by Norievill B. España, Wilfredo Y. Licuanan, and Porfirio M. Aliño

Climate change driven disturbances such as increases in sea surface temperature (SST) pose a critical threat to coral reefs. Increased understanding of the mechanisms that maintain coral community structure (i.e., coral cover and species diversity) now allows for the assessment of resilience of coral communities to thermal stress. Such an assessment was conducted in Talim Bay, Lian, Batangas and sought to quantify factors that relate to resistance (i.e., coral community structure) and recovery potential (i.e., coral recruitment, topography of the reef and historical data on mortality and recovery). The Bay was found to be dominated by bleaching-resistant coral species, suggesting high resistance to thermal stress. Recovery potential was also assessed to be high and was associated with the physical characteristics of the reef, the coral size structure, and the presence of adjacent reefs for reseeding. Sedimentation and nutrient loading were found to have a significant role in determining the status of the coral communities of Talim Bay. Insights from this resilience assessment may inform coastal communities of management measures which are necessary to alleviate stress on coral reefs to minimize coral reef degradation and phase shifts... Continue reading


Posted on August 25, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 37-40
POP SCIENCE

Coconuts and the Filipino Diaspora

by Augustine Doronila

The common coconut tree niyog in tagalog or lubi in my parents ilongo has given me a strong sense of my roots to the Philippines. It may be argued that strictly speaking it is not an indigenous tree as it is grown far and wide in the tropical regions of the world. Its geographical distribution in fact has been so intimately connected with the major waves of human migration around the tropical regions of the Pacific, Indian and also the Atlantic oceans. We are taught from an early age that it is the "The Tree of Life" because of the abundant number of products and by-products derived from its various parts. To the 1st seafaring migrants from the Indo-Malay (including the Philippines) region and further afield it was a portable source of food, water, fuel and building materials... Continue reading


Posted on July 30, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 36-36
ARTICLE

An individual-based model of long-term forest growth and carbon sequestration in planted mangroves under salinity and inundation stresses

by Severino G. Salmo III and Dranreb Earl O. Juanico

We developed a spatially explicit individual-based model of forest development trajectories of monospecific Rhizophora mucronata plantations. The model incorporates stochastic initial seedling spacing, propagule dispersal, recruitment, and mortality. We simulated and compared the growth, development and accumulation of carbon stocks of restored mangroves between optimal and sub-optimal settings. Salinity is considered as a stressor, while flooding effects are described as an inundation stress factor. In the optimal setting, the simulated mangrove population accumulated large aboveground carbon stocks (of around 140 T/ha) after 100 years. Under sub-optimal conditions, we observed delayed maturity by at least 10 years near the salinity threshold and the carbon stock decreased through time towards much lower values (25 T/ha). More importantly, the continuous presence of stressors may lead to forest population collapse (at 50 yrs post-planting) probably as a result of the accumulated effects of physiological stresses. Thus, restored mangrove populations that are located in highly saline and frequently inundated sites, may eventually collapse even though they may appear to be healthy in the early stages of forest development. Our results imply that current and future restoration practices should carefully consider site selection in order to ensure viable long-term forest development and to have an optimum contribution to carbon sequestration... Continue reading


Posted on July 28, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 31-35
ARTICLE

Molecular profiling of culturable bacteria from portable drinking water filtration systems and tap water in three cities of Metro Manila, Philippines

by Edward A. Barlaan, Janina M. Guarte, and Chyrene I. Moncada

Many consumers drink filtered water from portable filtration system or directly from tap water. However, microbial community composition in portable drinking water filtration systems has not yet been investigated. This study determined the molecular profile of culturable bacteria in biofilms and filtered water from portable drinking water filtration systems and tap water in three key cities of Metro Manila, Philippines. A total of 97 isolates were obtained using different growth media and characterized based on 16S rRNA gene sequences. Most bacteria were isolated from biofilms, followed by filtered water and the least from tap water. Many isolates were affiliated with Proteobacteria (α, β, and γ), Actinobacteria, Firmicutes and Bacteriodetes; some had no matches or low affiliations in data bank. Many isolates were associated with bacteria that were part of normal drinking water flora. Some were affiliated with opportunistic bacterial pathogens, soil bacteria and activated sludge bacteria. The presence of soil and opportunistic bacteria may pose health risks when immunocompromised consumers directly drink the tap water. Some isolates had very low percentage homology with bacterial affiliates or without matches in the data bank suggesting different identities or novelty of the isolates. Further studies are needed for different portable filtration systems available in the market, drinking water quality status of other areas and functions of the isolated bacteria. This study is the first report on the use of potato dextrose agar for isolation of bacteria from water environment. It is also the first report on molecular profiling of culturable bacteria in biofilms and filtered water in portable drinking water filtration systems... Continue reading


Posted on July 27, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 24-30
SHORT COMMUNICATION

Development of microsatellite markers for genetic diversity analysis in Glossogobius giuris (Hamilton, 1822) and Rhinogobius giurinus (Rutter, 1897)

by Abriel S. Bulasag, Nathalie T. del Agua, Aprill S. Punongbayan, and Maria Genaleen Q. Diaz

Microsatellite-enriched libraries were constructed from Glossogobius giuris and Rhinogobius giurinus. BLAST analysis revealed significant homology of the clones with microsatellite-rich regions in other teleosts and other members of Gobiidae. Eight microsatellite primers were designed and tested for cross-amplification in two other goby species, Glossogobius celebius and Gobiopterus lacustris. Four primer pairs amplified putative microsatellite loci in all four species. Four other primer pairs amplified loci in at least two species. Primer Rh18 was the most informative and exhibited the greatest number of polymorphic alleles (PIC=0.7262; Na=7). Two other primers, Rh51 and Gi47 were also informative markers with PIC values ≥ 0.5. Using five primers, both G. giuris and R. giurinus samples exhibited moderately high values of genetic diversity based on the number of alleles (~5), percent polymorphism (53%), and observed (61%) and expected (58%) heterozygosities... Continue reading


Posted on July 15, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 19-23
ARTICLE

Isolation and characterization of culturable thermophilic bacteria from hot springs in Benguet, Philippines

by Socorro Martha Meg-ay V. Daupan and Windell L. Rivera

Despite the numerous geothermal environments in the Philippines, there is limited information on the composition of thermophilic bacteria within the country. This study is the first to carry out both culture and molecular-based methods to characterize thermophilic bacteria from hot springs in the province of Benguet in the Philippines. The xylan-degrading ability of each isolate was also investigated using the Congo red method. A total of 14 phenotypically-different isolates (7 from Badekbek mud spring and 7 from Dalupirip hot spring) were characterized. Phylogenetic analysis based on the nearly complete 16S rDNA sequences revealed that all the isolates obtained from Badekbek were affiliated with Geobacillus, whereas the isolates from Dalupirip clustered into 3 major linkages of bacterial phyla, Firmicutes (72%) consisting of the genera Geobacillus and Anoxybacillus; Deinococcus-Thermus (14%) consisting of the genus Meiothermus; and Bacteroidetes consisting of the genus Thermonema (14%). In addition, xylan-degrading ability was observed in all isolates from Badekbek and in 2 isolates from Dalupirip which showed high sequence similarity with Geobacillus spp. The results are also essential in understanding the roles of the physico-chemical properties of hot spring water as a driver of thermophilic bacterial compositions... Continue reading


Posted on July 11, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 14-18
COMMENTARY

The “Land for Skills” Program: A Mechanism for Conserving Research and Human Resources in a Developing Country in the Era of Globalization

by Teodoro Tigno Jr.

The problem of developing countries in transitioning their emerging economies into the relative stability of fully developed ones has never been more closely reflected during the era of Globalization, than in the crucial factor of conserving human resources for their own development. In this working paper, the author analyzes the bases of this predicament for developing countries in general and proposes a pathway for sustaining Research and Development (R&D) manpower in a pilot project in the Philippines... Continue reading


Posted on July 5, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 9-13
ARTICLE

Levels and sources of potassium, calcium, sulfur, iron and manganese in major paddy soils of the Philippines

by Jehru C. Magahud, Rodrigo B. Badayos, Pearl B. Sanchez, and Pompe C. Sta. Cruz

Nutrient levels in rice areas can be translated to the soils’ capacity to supply the essential elements for rice, while information about nutrient sources can be used to formulate management options to areas deficient or toxic in nutrients. This study was then conducted to assess the potassium (K), calcium (Ca), sulfur (S), iron (Fe) and manganese (Mn) levels in the Philippines’ major rice areas. The study also determined the contributions of soil properties, land uses, irrigation water, and farm practices to the nutrient levels. Strategic collection of soil and plant samples, laboratory analyses of samples, and farmer interviews were done. Potassium concentrations of rice plants in La Paz (Tarlac) and Sta. Rosa City (Laguna) exceeded the toxic concentration of 3%. These K concentrations can be due to the increase of the nutrient’s availability owing to the neutral soil pH levels in the two sites. The highest total Ca levels were found in the Polangui (Albay), La Paz, and Villasis (Pangasinan) soils. These Ca levels can be ascribed to the occurrence of Ca in sand and silt-sized soil fractions. Total Fe and Mn concentrations were very high in the Sta. Cruz (Zambales) soil due to the input of mine wastes. The San Leonardo (Nueva Ecija) soil’s high total Fe concentration is probably due to the occurrence of Fe in clay-sized soil fractions. Iron and Mn levels of rice in most Central Luzon sites exceeded the toxic concentrations of 1000 mg kg-1 for Fe and 300 mg kg-1 for Mn. These concentrations can be due to the high total soil Fe and Mn levels, and their increased plant uptake due to periodic soil submergence and increased soil acidity from continuous cropping. The study implies that K, Ca, Fe and Mn are enriched in rice areas due to soil properties and farm practices... Continue reading


Posted on July 1, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 2 Page 1-8
POP SCIENCE

Sustained Global Attention to Emerging Pandemic Threats and Risks:
The need to strengthen One Health systems and Whole-of-Society preparedness

by Noel Lee J. Miranda

Severe outbreaks of flu, SARS, Ebola, and other highly transmissible and fatal infectious diseases are major challenges to health and global security. For instance, the ongoing Ebola outbreak in West Africa, which has caused wide-scale socio-economic disruptions, is considered to be unprecedented in scope, severity and complexity. It has heavily impacted on livelihood, business, essential services and economic activities... Continue reading


Posted on June 9, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 58-59
ARTICLE

Finding the optimal dose for psoriasis ultraviolet radiation therapy through multi-objective evolutionary optimization on a skin model

by Arjay C. Cayetano, Francisca C. Roa, Eduardo R. Mendoza, and Prospero C. Naval, Jr.

Ultraviolet radiation (UVR) is proven to be an effective treatment for psoriasis yet it needs to be carefully controlled since it is a widely known carcinogen. Due to the time-consuming, expensive and hazardous nature of clinical tests on actual patients, the range of possible values for the optimal regimen set has not yet been thoroughly explored. An agent-based model was constructed in order to study the complex role of UVR in psoriasis phototherapy, including possible contribution to the formation of skin cancers. The treatment progression of the simulated psoriasis undergoing UVR phototherapy was monitored weekly and compared with the corresponding clinical data. For model calibration, a single-objective optimization via genetic algorithm was employed that aimed to minimize the discrepancy between the model output and the expected clinical result. After fitting and validation, the model was then subjected to multi-objective evolutionary optimization using Non-dominated Sorting Genetic Algorithm-II (NSGA-II) in order to suggest sets of optimal UVR phototherapy regimen for psoriasis taking into account the safety, clearance time as well as aggressiveness of the therapy. Results show a good model fit against clinical data and gave some plausible sets of dosimetry for UVR phototherapy that maximize its therapeutic efficacy while minimizing the associated skin cancer risk... Continue reading


Posted on May 30, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 52-57
ARTICLE

Biochemical and molecular characterization of two 11S globulin isoforms from coconut and their expression analysis during seed development

by Kristian Mark P. Caldo, Roberta N. Garcia, and Evelyn Mae Tecson-Mendoza

Cocosin, the 11S globulin of coconut, is the major storage protein that accumulates in the endosperm during seed development. This work describes the gene structure, derived amino acid sequence, structural homologies, and developmental expression profile of cocosin. Two full-length cocosin cDNAs spanning 1,641 and 1,623 nucleotides and encoding for 466 amino acids were isolated through PCR cloning strategy coupled with 5′ and 3′-RACE technologies. Both sequences displayed 92.3% nucleotide identity and 91.5% amino acid identity. They both exhibit the following conserved regions among 11S globulins/glutelins of various seed plants―signal peptide targeting storage vacuole deposition, highly conserved asparaginyl splice site dividing the polypeptides into acidic (32 kDa) and basic (21 kDa) subunits, bicupin domain and four cysteine residues involved in intra- and inter-chain disulfide bonding. Phylogenetic analysis showed that cocosin is more closely related to Elaeis guineensis glutelin, both of which form a distinct clade in the tree between the divergent clades of dicot and cereal 11S globulins. The predicted three-dimensional structure of the cocosin exhibits the bicupin domain separated by a less conserved loop. Relative PCR and western blot analysis showed that synthesis of cocosin started at 6–7 months after pollination (MAP) and increased continuously up to 8–9 MAP. Western blot analysis further showed that majority of cocosin was deposited at 11–12 MAP... Continue reading


Posted on May 22, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 46-51
ARTICLE

Electrical properties of an individual ZnO micro/nanorod

by Alexandra B. Santos-Putungan, Leonalyn M. Bambao, and Roland V. Sarmago

Free standing, highly crystalline ZnO micro/nanorods have been successfully fabricated using low temperature hydrothermal synthesis. Current-voltage characteristic curves show that ZnO micro/nanorods’ resistances are proportional to their geometrical ratios, satisfying classical Ohm’s law. Temperature-dependent resistance measurements reveal exponential decay of current with temperature, implying good semiconducting properties. Finally, three different thermally-activated impurity levels were identified from the measurements, and these are attributed to Zn interstitials in the bulk. The results are important in supplementing research in nanoelectronics and nanocircuitries... Continue reading


Posted on May 12, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 43-45
POP SCIENCE

Rubbing Elbows with Nobel Laureates and Japanese Royalty

by Imee Su Martinez

Every year when the Sakura quiver in anticipation for spring, the Japan Society for the Promotion of Science (JSPS) invites promising young scientists from the Asia-Pacific and Africa to a gathering called the HOPE Meeting. “HOPE signifies the promise held by young scientists, and the optimism for a bright science and technology future” (JSPS, 2010). This meeting provides opportunities for starting researchers to interact with Nobel Laureates in order to expose them to the highest level of scientific endeavors, and to inspire them to aim for loftier goals. The meeting also intends to foster collaborations among the participants, and to provide them avenues for stimulating intellectual discussions... Continue reading


Posted on May 9, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 41-42
ARTICLE

An assessment of chronotype and social jetlag among Filipinos

by Roselyn S. Gabud, Gayline F. Manalang Jr., Richard Bryann L. Chua, Eduardo R. Mendoza, and Jingky P. Lozano-Kühne

Chronotype is a measure of an individual’s timing of sleep and wakefulness. It describes the relationship between an external time and a person’s internal biological time. The chronotype has been used to characterize human circadian trait. Differences in chronotypes are believed to be related to genetic variation, location, geographic and cultural factors. Determination of chronotype using quantitative approaches has been done in Europe for more than a decade now through the Munich Chronotype Questionnaire (MCTQ). In this approach, the chronotype is quantified by the midpoint time between the start and end of sleep during free days, corrected for sleep duration on work days. The calculated time classifies whether an individual has an early or late chronotype. In the Philippines, there is no existing data for chronotypes as well as social jetlag – the discrepancy between an individual’s internal time and social clock. In this study, we provide a quantitative description of chronotypes and social jetlag among Filipinos. We present preliminary results based on the 895 non-shift worker respondents of the PhilMCTQ, a language variant of the MCTQ for the Philippine population. Using this set of data, we determined the association of chronotype and social jetlag against certain factors, i.e., age, gender, self- assessed exposure to natural light, type of location (whether living in the urban or rural area), travel time to/from work, sleep duration, and body mass index. Observations concerning the relationship of chronotype and gender, age and social jetlag that have been previously reported in other populations are also seen in our data. Increased social jetlag has been observed among people with late chronotypes among our respondents. There were also some differences in chronotypes between genders, age groups, dwelling locations and consumers of stimulants (i.e., beer, liquor and cigarettes). Both Metro City and Non-Metro City residents similarly experience social jetlag. The data show that as commuting time becomes longer, social jetlag slightly increases. Differences in social jetlag have been observed between age groups and certain stimulants (e.g., smoking, coffee drinking) have been shown to be associated with social jetlag. Other factors such as gender, dwelling location, time spent outdoors and body mass index did not show sufficient evidence of association or correlation with social jetlag among the study participants... Continue reading


Posted on May 8, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 31-40
ARTICLE

New records of an Invasive Calanoid Copepod, Arctodiaptomus dorsalis (Marsh, 1907) in freshwater ecosystems in the Bicol Peninsula (Luzon Is., Philippines)

by Eric Zeus C. Rizo, Jhaydee Ann F. Pascual, Duke Jesse B. Dy, Lorenzo Jose A. Labicane, Clarice B. Trinidad, and Rey Donne S. Papa

Arctodiaptomus dorsalis is a Neotropical freshwater calanoid species that is now widely distributed throughout the Philippines because of its ability to adapt well to eutrophic environments and aquaculture. A previous survey already confirmed the presence of A. dorsalis in three lakes in the Bicol peninsula. The primary goal of this study was to determine the extent of the occurrence of A. dorsalis in Bicol given its ability to displace native calanoid species. Samples were collected from 34 freshwater bodies throughout the Bicol Peninsula spanning the provinces of Camarines Norte, Camarines Sur, Sorsogon and Albay. Our results show that A. dorsalis is now recorded from five freshwater ecosystems in Bicol that are linked either through natural connections, aquaculture, or water system constructions. This includes man-made structures such as Lago del Rey and the Camarines Sur Water Sports Complex, and natural freshwater ecosystems such as Lake Buhi, Lake Danao and the Bicol River. Except for Lake Buhi, the other four sampling sites are new locality records for A. dorsalis. Translocation of fishes and passive dispersal through natural or man-made channels aided the dispersal of A. dorsalis in these areas. Though only 14% of the total sampling sites were positive for A. dorsalis, it occurred in the larger water bodies (natural and man-made lakes and large rivers) in the region including one, Lake Buhi, that previously contained native calanoid species such as Tropodiaptomus vicinus. Our results confirm the absence of Tropodiaptomus vicinus from Lake Buhi and the dominance of A. dorsalis in the pelagic plankton community of freshwater ecosystems. It would seem that A. dorsalis invasions in this area are more successful in inter-connected larger freshwater ecosystems... Continue reading


Posted on April 27, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 27-30
ARTICLE

Ordinal regression analyses of breastfeeding duration in the Philippines

by Jesper L. Abolencia, Ananias G. Quipit, Jr., Robert Neil F. Leong, and Frumencio F. Co

This paper offers a different perspective in identifying significant correlates of breastfeeding duration. In particular, a proportional odds ordinal regression model with a cumulative logit link is fitted using NDHS 2008 data. Results of the analysis showed that female infants are 15% more likely to be breastfed longer than their male counterparts. Moreover, it was also observed that latter born children are 26% more likely to be breastfed longer than earlier born children. These findings suggest the necessity to perform in-depth studies to better explain the results. Moreover, the results of this analysis have verified previous literature findings relating increased modernity of mothers (mothers with higher educational attainment, higher wealth status, and domiciling in urban areas) with shorter breastfeeding practice. The latter findings suggest that with increased modernity being possibly related with gainful employment, improving breastfeeding practices among these mothers may be done through development of breastfeeding supports in work stations... Continue reading


Posted on April 25, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 22-26
ARTICLE

Symmetry-breaking bifurcations in two mutually delay-coupled lasers

by Juancho A. Collera

We consider a symmetric system of delay differential equations arising from a model of two mutually delay-coupled semiconductor lasers. The system is described using the Lang-Kobayashi rate equations whose basic solutions are called compound laser modes (CLMs). We employ a group-theoretic approach to find solutions and to identify symmetry-breaking steady-state and Hopf bifurcations. This classification allows us to predict the symmetry group of a bifurcating branch of solutions from a symmetry- breaking bifurcation. Methods and techniques used in this study can be extended to larger symmetric laser networks... Continue reading


Posted on April 19, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 17-21
REVIEW

Population, economic growth, and inclusivity

by Ernesto M. Pernia and Elena E. Pernia

Given that the population variable figures centrally in both labor and product markets, this paper argues that the growth rate of population, its age structure and spatial distribution should be key considerations in a country’s development strategy to promote rapid and sustained economic growth, full employment, poverty reduction, and social inclusion. This represents a shift from the inordinate emphasis on the demand for labor, i.e., job creation. Significantly reducing unemployment and poverty can be achieved not solely through job generation but also by managing the quantity and quality of the work force, which is determined, with a lag, by the growth rate and structure of the population. The paper provides a perspective on population as it impacts the labor market and poverty. It then discusses issues of fertility and unmet needs for family planning and reproductive health services in relation to poverty. This is followed by a glimpse into regional experience in population policy, family planning, and poverty as exemplified by Thailand and Bangladesh. The penultimate section provides simulations and projections using different assumptions of contraceptive prevalence rates that result in various scenarios of fertility and population growth... Continue reading


Posted on April 12, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 12-16
FEATURE

A Scientist's Primer to Benito Vergara National Scientist

by Clarissa C. David

Dr. Benito S. Vergara is popular for yet another reason. While his contributions to rice science as a research scientist at the International Rice Research Institute (IRRI) are important, his legacy lies in communicating science to non-scientists. Among hundreds of publications in scientific journals is his most popular work, A Farmer's Primer on Growing Rice, an illustrated manual that is one of the world's most widely published agricultural texts (Hargrove, 2001). The official version of the Primer has been translated into more than 45 languages, with more than 50 separate translations including Waray, Farsi, Kiswahili, Malagasi, Bengali, Khmer and others. His passion in promoting science to the public continued even in his retirement years, when he helped build museums and published photo catalogs of ornamental plant varieties... Continue reading


Posted on April 2, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 8-11
WHITE PAPER

Philippines Innovation Ecosystem Assessment: Executive Summary

by Science, Technology, Research and Innovation for Development (STRIDE)

According to the US National Science Foundation, the term innovation ecosystem refers to the "economic...dynamics of the complex relationships...between actors or entities whose functional goal is to enable technology development and innovation." (Jackson, D. 2011) Growth of the innovation ecosystem requires that two distinct but interdependent systems—the knowledge economy (driven by fundamental research) and the commercial economy (driven by the marketplace)— work together to move innovation from laboratory to marketplace. In this cycle, a fraction of profits from business is, either directly or through government spending, channeled to support research activities. In turn, investments in research generate innovation-induced growth in the economy, creating greater profits in the commercial sector through new products and services. When new profits are reinvested in research activities, the cycle becomes self-reinforcing, and sustained technology-led economic growth is the result... Continue reading


Posted on March 8, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 2-7
EDITORIAL

International Journal of Philippine Science and Technology

by Gisela Padilla-Concepcion and David Hall

Phil Sci Tech is a new journal, building on the excellent previous work of Philippine Science Letters (PSL). PSL was the brainchild of Gisela P. Concepcion, Professor of The Marine Science Institute (MSI), University of the Philippines. Gisela and Eduardo A. Padlan, Adjunct Professor at MSI, have been serving as PSL’s co-editors till the present. PSL has featured science done in the Philippines and done by Filipinos elsewhere, and also featured the work of prominent Filipino scientists... Continue reading


Posted on February 6, 2015 in the International Journal of Philippine Science and Technology 2015 Volume 8 Issue Number 1 Page 1

Announcements

STRIDE Grants The next call for Grants will commence on February 27, 2015. To know more about the Grants program of STRIDE, you may visit our website at stride.org.ph.