Volume 2 No. 1

January 1999
Light & Shadow at the DLSU: Not a problem at all for the  quantum yield of photosystem II (Y) of plants growing  on the campus: But how to determine Y experimentally?

Light & Shadow at the DLSU: Not a problem at all for the quantum yield of photosystem II (Y) of plants growing on the campus: But how to determine Y experimentally?

pp. 23-48 (Volume 2 No. 1 1999)

Hartmut Gimmler 1
Julius-von-Sachs-lnstitute of Life Science
University of Wirzburg, Julius-von-Sachs-Platz 2
97082 Wi.irzburg, Germany

Josefina De Jesus & Jose Santos Carandang VI 2
Biology Department, De La Salle University-Mani/a
2401 Taft Avenue, 1004 Manila, Philippines

ABSTRACT

This science education report introduces the technique of pulse amplitude modulated (PAM) fluorescence measurement of chlorophyll for the sensitive, noninvasive and rapid determination of quantum yield of photosystem II (y) in both laboratory and field experiments by the application of a portable chlorophyllfluorometer, the so-called Mini-PAM. In a case study we applied the Mini-PAM for the comparison of Y of various ferns and higher plants adapted to different light intensities on the DLSU campus. Y values were determined for both dark adapted, detached leaves (maximal quantum yield) and plants in the field exposed to natural irradiation (actual steady state Yvalues). Data show that maximal quantum yield of photosystem II varies in the measured 80 species within a narrow range (0. 720 ± 0. 009) and is totally independent upon the adaptation of plants to different irradiation during growth. In most cases Y values of the upper side of the leaves are slightly, but significantly higher than those of the lower sides. However, large differences are observed with various plants when the quantum yield of photosystem II is plotted as function of light intensity. There is linear correlation among those light intensities which cause half maximal inhibition of qilantum yield of photosystem II and the actual yields measured at an irradiation of 1000 µmo/ quanta m·1 s·1 PAR, which corresponds approximately to half of full sunshine. The different shapes of light intensity curves which are saturation curves, allow the distinction between typical shadow and sun plants and those tolerating relatively broad range of light intensities in between.

Quasilocal Background Approach to the One-loop Effective Action

Quasilocal Background Approach to the One-loop Effective Action

pp. 6-13 (Volume 2 No. 1 1999)

Emmanuel T. Rodulfo
and Michelle M. Tiamzon
Physics Department, De La Salle University-Manila
2401 Taft Ave., Manila 1004 Philippines

ABSTRACT

The one-loop effective action that accommodates an arbitrary number of covariant derivatives of a strong but slowly-varying background field is presented in closed form. The internal symmetry and spacetime dimension are kept arbitrary in the formalism. The first few terms in the perturbative expansion of the one-loop effective action are derived and are found to agree with those obtained
using popular methods.

Soil Transmitted Roundworm Infection on Grade Two Students

Soil Transmitted Roundworm Infection on Grade Two Students

pp. 1-5 (Volume 2 No. 1 1999)

Louella Brion
Natural Science Area Coordinator
DLSU-College of St. Benilde
2544 Taft Avenue, Manila 1004 Philippines

Abstract

Stool specimen from 239 randomly-selected Grade II students of General Tiburcio de Leon Elementary School were collected to determine the prevalence and intensity of soil-transmitted roundworm infection among these students, and to correlate this with their academic achievement. The formalin-ether concentration technique (FECT) was used to process these specimen. Ascaris and Trichuris were the predominant parasites detected. Trichuriasis was detected in 46% of the students, while Ascariasis was detected in 36% of the respondents. Most of the respondents had light parasitic infection, while only 1.8% had moderate infection. There is higher prevalence of these infections among males as compared to females, but the difference in prevalence was not significant. The students’ GPA as measure of their academic achievement were correlated with the existence of infection. A significant negative correlation was found (r=-0.204, p < 0.05) between these two variables. This means that students without infection have the tendency to have higher grades.

Contemplating A Scientific Science

Contemplating A Scientific Science

pp 61-63 (Vol. 2 No. 1 1999)

Education Reform
Allan B. I. Bernardo
College of Education, De La Salle University-Mani/a
2401 Taft Avenue, 1004 Manila,Philippines

We have all been hearing a lot about the lugubrious state of science education in the Philippines since the release of  the Third International Mathematics and Science Survey (TIMMS) results. In the survey, the Philippine sample performed dismally, ranking near the bottom of the list’. What was actually more surprising was that local testing data have long portrayed the same dismal picture of sci­ence achievement of our students…

Leonid Showers

Leonid Showers

pp 59-60 (Vol. 2 No. 1 1999)

Robert Roleda
Science Education Department
De La Salle University-Mani/a
2401 Taft Avenue
1004 Manila, Philippines

INTRODUCTION

Amateur astronomers in the Asia-Pacific region experienced a big letdown on the early hours of November 18, 1998 as the much anticipated meteor storm occurred 14 hours earlier than predicted, peaking over the Atlantic Ocean at five hours Universal Time. Two thousand meteors per hour were reported over the Canary Islands and 500 were reported by experienced watchers in France and Israel. 

Synthesis of o-Galactose-Modified 1,3-Dithiole-2-Thione Derivative

Synthesis of o-Galactose-Modified 1,3-Dithiole-2-Thione Derivative

pp 49-52 (Vol 2 No. 1 1999)

Glenn Alea, Philip Reginald Alto,
Emmanuel Garcia, Gerardo C. Janairo*,
Jose Mari C. Quibilan and Derrick Ethelbert C. Yu
Chemistry Department, De La Salle University-Manila
2401 Taft Ave., Ma/ate, Manila, 1004 Philippines

ABSTRACT

A procedure for the synthesis of the novel 4-mercapto-5-(6-0-2’­cl hyl ene-1, 2: 3, 4-di-0-isopropylidenegalactopyranosy/ thio)-1, 3- dithiole-2-thione (7) is described.