Thursday, October 6, 2011

Literacy Training Service - It's Finally Over

My classmates and I in LTS taught Grade 3 students for one semester. It's now the end of the sem and I realized that...


There are different kinds of students. K
There are students who don’t perform well in class because the teachers don’t appreciate and encourage them—this means ONE BY ONE! These students seem to be slow learners but in fact they are above average. I had one student who is really good but she has low self-esteem. She in fact answers correctly but her seatmates, well sometimes, teases her that her answer is not correct—so she changes it. K At the start of the semester, her performance is not so good but when I started appreciating (even if her scores are not that high) and encouraging her that she can do it, she does well.
There are students whose minds are really wandering. It’s hard to get them listen to you; you have to make more gimmicks! Some of them could really be intelligent but some… well, I hope they are good in music or sports or in other things. So, the teachers should help them in the subjects that they really find hard to understand.
There are students who are confident but they really shouldn’t be. HAHA! I know this is also happening in our University. In this case, the teacher should tell the student, in an appropriate way, that he/she got the wrong idea… Again, in an APPROPRIATE WAY!
There are students who are really good. (I don’t even know why they are taking our LTS 2 Program.) Teachers should encourage these students to always perform better.
There are good students who are really scared of English. I don’t know why but actually, they are good in English… sometimes, better than those who aren’t scared of it. HAHA! J
There are students
·         Who will ask you to give them P 10.00 (ten pesos) K
·         Who would want to be absent because they hate you… K
·         Who tell you that they love you and they’ll miss you (sweet)…

To be a more effective teacher…
                We always have to see the needs of the students and we shouldn’t bombard them with stuff that would be of no help to them. For example, during our first day of teaching, we taught CVC since their teachers advised us to do so. Too bad that the students don’t even know what the vowels and the consonants are. K We have to be friendly but we have to show authority. If the teachers aren’t friendly, the tendency of the student to be under pressure or be scared—they won’t be able to learn something if that’s the case.

Tuesday, August 23, 2011

The Conservation Status of Philippine Frogs (2010)

I. Introduction to the Philippine Anuran Diversity

The Philippine frogs consist of eight families and 106 species. These are widely distributed to different habitats—rocks, forest floors, leaf axils, streams, flooded rice fields and limestone crevices.
Basically, the key to Philippine Anurans is a collection of keys to different families of Philippine frogs. Eighty-four dichotomous keys were compiled.
            Nowadays, the number of our endangered frogs is increasing—this is not a good picture because they serve as bioindicators of air and water pollution since they can breathe and drink through their skin. Anurans are also found to be very useful for agricultural purposes due to their ability to act as a biological pest controlling agents. Moreover, most of the endangered frogs are native and endemic, thus, they should be treated as natural and living treasures that could just appear once or twice in the earth’s lifetime, specifically in our country’s lifetime.

II. The Distribution and Conservation Status of Philippine Frogs

Sixteen of the native and endemic anurans are already endangered and one of is critically endangered. Thirty-one are considered vulnerable.
            Not all frogs in the Philippines are native, some are only introduced and even invasive. One of the invasive frogs, the Giant Marine Toad or Bullfrog (Rhinella marina) from the Americas, has already spread out all over the Philippines. It is the most widely distributed alien frog in the Philippines.

III. Factors threatening the number of Philippine Anurans

            There are several factors affecting the increasing number of threatened Philippine frogs—habitat destruction, fungal infections, herbicides and pesticides, introduced predators and invasive species, human exploitation and climate change.

IV. Promoters of the conservation of the Philippine Anurans

            IUCN Species Programme (International Union for Conservation of Nature) promotes the conservation of species, subspecies, varieties and subpopulations on a global scale, including the Philippines. The organization highlights threatened taxa.
            Herpwatch Philippines is a non-profit organization whose members are academic herpetologists, conservation biologists, wildlife managers, biodiversity specialists, students, and laypersons. The goal of the group is to promoting herpetological studies and conservation of amphibians and reptiles in the Philippines.
            ZOO 145, a Herpetology class in UPLB that is led by Dr. Leticia Afuang, aims to help the students to have a deep knowledge on the Philippine Herpetofauna as well as awareness on their conservation status.

SUMMARY AND CONCLUSION:

            The Philippine Anurans play an important role in the ecosystem since they serve as bioindicators and they are a part of food webs. As of 2010, the Philippine Anurans consist of 106 species but 47 of these, all native and endemic, are already threatened due to habitat destruction, parasites, infections, predators and other invasive species. Thus, the conservation of the Philippine Anurans is very important so organizations and individuals promote the protection and preservation of these frogs.

REFERENCES:

Key to the Families of Philippine Amphibians by ZOO145 H-1L 1st Semester 2009-2010.

Inger, R. F. 1954. Systematics and zoogeography of Philippine Amphibia. Fieldiana: Zoology, 33(4):183-531.

Taylor. E. H. 1920. Amphibians and Turtles of the Philippine Islands. Philippine Journal of Science 16: 111-144; 213-359.

Brown, W.C., Alcala, A.C. and Diesmos, A.C. (1999). Four New Species of the Genus Platymantis (Amphibia:Ranidae) from Luzon Island, Philippines. Proceedings of the California Academy of Sciences vol. 51 (12):449-460.

Brown, R.M., J.A. McGuire and A.C. Diesmos. (2000). Status of Some Philippine Frogs Referred to Rana Everetti (Anura: Ranidae), Description of a New Species, and Resurrection of Rana Igorota Taylor 1922. Herpetologica 56(1): 81-104.

Brown, W.C., Alcala, A.C., Diesmos, A.C. and Alcala, E. (1997). Species of the Guentheri Group of Platymantis (Amphibia:Ranidae) from the Philippines, with Descriptions of Four New Species. Proceedings of the California Academy of Sciences vol. 50 (1):1-20.

Brown, W.C., Alcala, A.C. and Walter, R.M. (1997). Species of the Hazelae Group of Platymantis (Amphibia:Ranidae) from the Philippines, with Descriptions of Two New Species. Proceedings of the California Academy of Sciences vol. 49 (11):405-421.

Brown, W.C., A.C. Alcala, P.S. Ong, and A.C. Diesmos. (1999). A new species of Platymantis (Amphibia: Ranidae) from the Sierra Madre Mountains, Luzon Island, Philippines. Proceedings of the Biological Society of Washington 112(3):510-514.

Diesmos, A.C., R.M. Brown, and A.C. Alcala. (2002). New Species of Narrow-Mouthed Frog (Amphibia: Anura: Microhylidae; Genus Kaloula) from the Mountains of Southern Luzon and Polillo Islands, Philippines. Copeia 2002(4):1037-1051.

Diesmos, A.C. Luzon Island, Philippines Frogs of Mt. Maquiling and Mt. Banahao. (Photos)

Evans, B.J., R.M. Brown, J.A. McGuire, J. Supriatna, N. Andayani, A. Diesmos, D. Iskandar, D.J. Melnick and D.C. Cannatella. 2003. Phylogenetics of Fanged Frogs: Testing Biogeographical Hypotheses at the Interface of the Asian and Australian Faunal Zones. Syst. Biol. 52(6):794–819.

Siler, C.D., C.W. Linkem, A.C. Diesmos and A.C. Alcala. 2007. A NEW SPECIES OF PLATYMANTIS (AMPHIBIA: ANURA: RANIDAE)FROM PANAY ISLAND, PHILIPPINES. Herpetologica, 63(3):351–364.

IUCN Red List of Threatened Species. <http://www.iucnredlist.org>.

Thursday, June 16, 2011

Science, Technology and Society: The Taal Lake Fish Kill

FISHKILL Workers bring to port tons of milkfish (“bangus”) killed in the Taal Lake in Batangas following a drop in temperature. ARNOLD ALMACEN (Inquirer News)

The Taal Lake Fish Kill has been the hottest issue a month ago and according to EarthWeek1 on June 3, 2011, more than 800 tons of farmed fish died abruptly when the water temperature of Taal Lake suddenly changed.
Now, the question is “Who’s to blame?” or “What to blame?” Could it be the technology? Could it be the society? Could the phenomenon be explained by science?
Basically, there are five (4) possible reasons why fish kill occurred in Taal Lake.
The volcano. Perhaps, the volcano gave out a lot of sulfur and thus, the fishes died. Sulfur can actually cause severe damage in vascular and enzyme systems of animals.2
Toxins and chemicals. If in case the fish farmers in Taal are using pesticides and other chemicals, these could be the culprit of the massive fish kill. Sometimes, the effects of these pesticides are also harmful to the fishes.
High water temperature. Since the earth is now experiencing global warming, which is contributed by man’s technology, the weather is hotter than ever… and due to a very hot weather, there was a change in temperature of the water. If the water is hot, the solubility of oxygen in water becomes low.3 Thus, the fishes in the lake could have found it difficult to breath and then died.
High number of plankton. Planktons are microscopic organisms found in water. If the water is concentrated with these organisms, there will be a competition for oxygen and other necessities like nutrients, sunlight, etc. Thus, a high number of plankton is a threat to the fishes. Just imagine a lake covered with planktons.
On the other hand, as confirmed in Philippine Star, there is a main reason for the fish kill.
Greed and ignorance. Joey de Venecia III referred to the fish cage operators in Philippine Star, “Their failure to follow the recommendations of the Bureau of Fisheries and Aquatic Resources to remove the cages which hampered the flow of tidal water in narrow areas was the main reason for the fishkill.”4 Perhaps, the cage operators do not want to remove cages because of the profits that they could get or they were just being ignorant.
Analysing and predicting the reasons why fish kill occurred in Taal, it is considered that Science, Technology and Society have a very tight interplay. Thus, considering one, the other two should be considered as well.

Monday, May 23, 2011

Full Report: Synthesis of Aspirin

(This is posted to help my fellow college students, but please, use this only as a guide and don't copy paste because it's bad.)

I. INTRODUCTION
Organic synthesis is the process where a desired organic compound is constructed or prepared from commercially available materials. The objective of organic synthesis is to design the simplest synthetic routes to a molecule.
Acetylsalicylic acid, also known as aspirin, is one of the most widely used medications to reduce fever and is also used as a pain killer. It is an acetyl derivative of salicylic acid. It is a white, crystalline, weakly acidic substance which melts at 135°C.
Aspirin is synthesized through the reaction of salicylic acid with acetyl anhydride which causes a chemical reaction that turns salicylic acid's hydroxyl group into an acetyl group, (R—OH R—OCOCH3).
For the reaction to take place, an inorganic acid such as phosphoric acid is used as a catalyst.

II. OBJECTIVES
At the end of the exercise, the student should be able to:
1.     be introduced to the concept of organic synthesis;
2.     synthesize acetylsalicylic acid from salicylic acid by nucleophilic acyl substitution; and
3.     differentiate acetylsalicylic acid from salicylic acid by simple chemical tests.

III. MATERIALS AND METHODS
IV. DATA
V. SAMPLE CALCULATIONS (For parts III, IV and V, please refer to your own data. Be resourceful in this one. LOL!)


IV. RESULTS AND DISCUSSION
The first part of the experiment was the preparation of Acetylsalicylic Acid (Aspirin). A white, milky mixture was obtained when salicylic acid, acetic anhydride and phosphoric acid (a catalyst) were mixed. The mechanism of the reaction is:

This shows that the oxygen in salicylic acid attacks one of the carbons in acetic anhydride. Also, the mechanism shows how acetic acid was separated from the acetylsalicylic acid.

In the first part of the experiment, heating of the mixture was done and a clear yellow liquid was obtained (Table 2). Heating was employed so that salicylic acid would melt and react with acetic anhydride. On the other hand, water was added after heating (not at the start of the experiment). This is to prevent the reaction of acetic anhydride with water at the start of the experiment, if this had happened, no aspirin could have formed. In this manner, acetic anhydride was decomposed after the formation of aspirin.

After the adding 40mL ice-cold water, cooling to room temperature and placing in an ice bath, the liquid became whitish/cloudy with white precipitates. This addition of cold water is very important in purification and isolation of the crystals from the liquid since aspirin is insoluble in cold water. Purification is needed to eliminate any salicylic acid and acetic anhydride that did not react, as well as the acetic acid product and phosphoric acid. In this part, purification is not yet complete (it was continued on the recrystallization part). Isolation was done through suction filtration, white, sugar-like crystals were obtained.

The crude/impure product was then weighed and it weighed 4.40g. This is quite far from the theoretical yield because it still contains impurities. This data was used to calculate the percent recovery on the latter part of the exercise.

The second part of the experiment was recrystallization. This is the second part of the purification process. Here, 95% ethanol was added dropwise to the crystals until dissolved and after this, distilled water was added dropwise until cloudy/until recrystallization. Ethanol was used to dissolve aspirin along with the impurities such as salicylic acid and others. Cold water, on the other hand, is used to recrystallize only aspirin, thus, leaving all the impurities behind. Since aspirin is an ester, it should not be recrytallized from hot water since esters hydrolyses in hot water. After cooling in an ice bath (which further facilitates recrystallization and purification), the mixture was then suction filtered.

The weight of the recovered sample was 2.85g. The calculations for percent yield was shown in Table 6. The percent yield was 109.25%, meaning there was a slight error. Perhaps, the sample was not weighed properly or it was weighed when still wet.  On the other hand, the calculated percent recovery was 64.77%. Certainly, another error occurred. This could be due to handling problems in suction filtration or drying, etcetera.

As for the melting point data, the range of the crude sample was 120-124˚C and the range of the purified sample was 122-124˚C. (Actually, there could have been an error here since I wasn’t able to observe it. A classmate just told me the MP range of purified sample, too bad, I forgot to tell my groupmates!). Comparing the results to the literature value of 135˚C, both the purified and crude had a precise value BUT since the purified sample has a narrower range, it is logically more comparable to the literature value (hehe!).

In Table 8, the differentiation of synthesized acetylsalicylic acid from commercially available aspirin was accounted for. The test used in this part was Iodine test, which is a test for the presence of starch (since iodine can form a black complex with starch).After dissolving synthesized aspirin in 2mL water and 1mL iodine solution, a mixture of red-orange liquid and white precipitates was obtained while when commercially available aspirin was dissolved in 2mL water and 1mL iodine solution, a black precipitate in a dark brown to black solution was formed. This shows that commercially available aspirin contains starch.

Other tests that were performed were summarized in Table 7. Since salicylic acid has a phenol group, it gave a positive result to FeCl3 Test and KMnO4 Test, both of which react with phenol. Acetic anhydride gave a positive result to water solubility test to form acetic acid. The recrystallized aspirin, an ester, did not give any positive result to the tests since esters do not react with FeCl3 Test, KMnO4 Test and Tollen’s Test. Small esters are actually fairly soluble in water but solubility falls with chain length and hydrophobic parts. Since aspirin has a hydrophobic aromatic ring, it did not dissolve in water. Having these results, the recrystallized sample was then identified (or assumed) as acetylsalicylic acid.


VI. SUMMARY AND CONCLUSION
Aspirin was prepared from the reaction of salicylic acid and acetic anhydride. Phosphoric acid was used as a catalyst. Upon addition of cold water, acetic acid was formed and thus eliminated. Other impurities like salicylic acid were removed upon the process of recrystallization.

The melting point range of the purified and crude samples were compared to the literature value and it showed that the purified sample is logically “near” to the literature value because of its narrow range.

The recrystallized product was differentiated from commercial aspirin through iodine test and it showed that the commercial aspirin contains starch. Other tests such as water solubility test, FeCl3 Test, KMnO4 Test and Tollen’s Test differentiated the starting materials, salicylic acid and acetic anhydride, from aspirin.

VII. REFERENCES
Rainsford, K. D. (2004). Aspirin and Related Drugs. USA: Taylor & Francis Inc, no page (e-book).

Whitten, K. W., R. E. Davis, M. L. Peck, G. G. Stanley (2007). Chemistry. 8th ed. USA: Thomson Brooks/Cole, p. 947.

http://wwwchem.csustan.edu/consumer/aspirincons/aspirincons.htm

http://en.wikipedia.org/wiki/Aspirin

Tuesday, March 15, 2011

Japan struck by natural disasters

Devastation in Northeastern Japan
Credit: BBC News
Who will ever imagine that this would happen to such a powerful country. The impact of the earthquake and tsunami was so devastating and now, it caused the malfunctioning of some nuke plants. Many lives were affected and many lives were lost. Let's continue to pray for them--for comfort and for a fast recovery.