News article involving forensic science

Forensic science used in investigation of rape case

This article from the New York Times tells of the investigation of the murder of Ms. Meredith Kercher.

Four years ago, Ms. Amanda Knox, 24, and her Italian boyfriend, Mr. Raffaele Sollecito, were accused of murdering Ms. Kercher during a orgy. Both the accused were found guilty, and they got different jail terms: Ms. Knox got 26 years, Mr. Sollecito got 25. They were convicted two years ago, in December.

The two were convicted in accordance to a 427-page report made by the jury, which included telephone printouts, computer logs and flourescent bloodstain-revealing chemicals.

Forensic investigations also revealed that there was another man present during the orgy, a 24-year-old called Rudy Guede. He was pulled into the picture after a bloody handprint was found in Ms. Kercher's room and his DNA was found on her body and on objects belonging to her. He was originally sentenced to 30 years, but was reduced to 16 years on appeal.


My reflections and views

This article shows how forensic science can help the police in tracking perpetrators, by using such evidence like bloodstains, fingerprints, telephone logs, etc.

Fingerprints assignment

According to theory, the most common type of fingerprint is the loop, and the least common is the arch.

Below is a 3-D pie chart I created using the data from the science wiki. It showcases how many of each type of fingerprint there are in our class. Enjoy!

In conclusion, it is true that the most common type of fingerprint is the loop, and the least common is the arch.

The case of the middle aged woman

According to the case, the woman is middle-aged, and a driver's licence belonging to her has been discovered. It indicates that she was born in the year 1940.

Assuming the year of her death to be 2011,

2011 - 1940 = 71

She was 71 when she died.

71 - 30 = 41
41* 0.06 = 2. 46 cm

Original height using tibia:

(33.5 * 2. 352) + 74. 775
= 153. 567 cm

Present height:

153. 567 - 2. 46 = 151. 107 cm

PHI - the golden ratio

The golden ratio, or phi, is a number that can work magic in our daily lives.

When rounded off to three decimal places, 1. 618, it can dtermine whether you look attractive or like a hideous monster. This ratio is determined by measuring one's body height from the foot to the navel, and then from the navel to the head. If the ratio between these two is about 1. 618, one is considered to be rather attractive. Unfortunately, that is not the case for me, as mine is about 1. 309... FAIL. Haha!

Anyway, this number is considered to be one of the most beautiful and perfect numbers in existence. A perfect example of this number in action is demonstrated in Leonardo da Vinci's the Virtruvian Man, an anatomically accurate diagram of the human body.

Skeleton measurements

This is the third part of the graded assignments, measuring a skeleton and myself, and finding my theoretical hight as well as the skeleton's.

Below are some graphs indicating my measurements.

If there are any discrepancies, this may be due to the parallax error.

Our measurements may be accurate, but they are not that precise (all the measurements here are rounded off to one decimal place.)

Avatar making

Picture of myself:

Picture of avatar:

Description of myself: Moderate height (156 cm), round hairstyle, fairly plump, wears blue glasses, has small mole on right cheek






Picture of Sarah (my cousin)

Picture of her avatar:

Description of her: small (she's 7), quite thin, has braided hair, large dark eyes, thin eyebrows, small nose and mouth

Reflection on forensic science module

At first, I thought forensic science would be boring and dreary, but I was proven wrong by the fun activities we conducted during this module. Through this module, I find that my skills of observation and deduction have become stronger, and I can think more clearly when analysing situations.

Forensic science- Lefty Lewis

Evidence that may have been left at the scene of the crime:

-Tyre marks near front gate when attempting to reverse vehicle
-Might have left patch of oil as car was parked
-Left footprints on freshly dug flowerbed on his way to balcony
-Fingerprints left behind on anything he touched (he forgot to wear his gloves)
-Dropped his torch and left it on the flowerbed
-Blood from small wound on his left hand would have been left on anything he touched with his left hand
-Grazed the gate of the house with his car, leaving paint behind
-Left marks on balcony window indicating forced entry

Evidence that may have been taken away by Lefty:

-Soil may have stuck to his shoes from the flowerbed
-He may have jacaranda flowers or leaves or seeds stuck to his shoes, as he parked his car under a jacaranda tree
-His vehicle may have tell-tale marks of an accident - there might be scratches on his rear mudguard
-His car tires may have dirt from the muddy area in front of the mansion
-Small glass shards from the broken window and bits of fabric from the curtain may have gotten stuck in Lefty's wound


Suggestion for forensic scientist:

-Do blood test on any bloodstains made by Lefty's small wound - there should be a match in the police database
-Analayse footprints found in flowerbed to determine size of person's feet, and examine shoe prints to look for recognisable characteristics e.g. deep grooves. The suspect's shoes can then be compared with the footprints.
-Search for fingerprints and compare them with any in database - Lewis has struck before
-Check torch for fingerprints made by Lefty - more fingerprints ensure that the suspect is guilty
-Compare soil from Lefty's shoes with soil found in flowerbed
-Mud from car tires can be compared with soil found in front of the mansion
-Lefty's wound can be examined for glass pieces and fabric that match the window pane and the curtain
-Lefty's shoes can be examined for jacaranda seeds, leaves or flowers that he may have trampled on
-Paint from Lefty's car can be compared with the paint found on the gate

My work

Since before I'd forgotten to add in some of my PowerPoints for my Science ACE, I decided to add in links to my PowerPoints on Google docs. 

DULL distilled water

Reproductive System

THE MOST EXTREME (show on Animal Planet)

THE MOST EXTREME is a television show broadcast on Animal Planet. This show showcases certain characteristics of animals that are extremely superior to our human qualities of the same genre.

-title screen of THE MOST EXTREME

Certain characteristics are featured of the different animals shown in the episode. All of them have a common characteristic, such as speed, physical strength, stamina and endurance, etc. Humans will also be compared to these animals in terms of ability.

An animal that really impressed me that was featured on THE MOST EXTREME was the water bear. This is an extremely small, microscopic creature that has incredible resistance abilities. it can survive being in a total vacuum, can withstand huge amounts of poison and radiation, and is resistant to heat and cold. Plus, it is found worldwide, mostly in places where mossy plants grow, such as lichen. Water bears are herbivorous, and they eat the lichen for food.

In conclusion, humans may be able to duplicate these incredible and unique properties of these special animals, with the help of modern science and technology. Humans may one day sport these amazing abilities...

A few pics of newly re-discovered animals

A coelacanth. Originally thought to be extinct, a large, fine specimen was caught in African waters in the year 1938.

An adult La Palma Giant Lizard. Extremely rare, there are only about 50 mature adults in existence that are ready for breeding.

The Arakan Forest Turtle, Heosemys depressa(not mentioned in post). Believed to be extinct since 1908, several dead specimens turned up in a Chinese food market in 1994. They are sold in Asian markets for food and are used in traditional Chinese medical cures.

Some animals that were thought extinct, then re-discovered...

Some animals were once thought lost to history, like the dinosaurs, who were killed due to natural unknown causes, and other animals who were driven to extinction by humans, such as the dodo. However, the 20th and 21st centuries saw the re-discoveries of some of hese rare and elusive creatures, once thought to be lost to mankind...

The coelacanth is one good example of an animal that was thought to be extinct. There ae two subspecies, Latimeria chalumnae and Latimeria menadoensis. It was re-discovered in the year 1938 by the curator of a museum, off the coast of South Africa. Since then, sightings have been reported off the coast of the Comoros Islands, and even the waters around Sulawesi, Indonesia. It is a fairly large fish, averaging 2 metres in length, and was around during the Cretaceous period, about 65 million years ago.

Another creature once thought to be extinct is the Cuban Solenodon, Solenodon cubanus. It is found in the country Cuba, and it is threatened by habitat loss and the introduction of human pets, such as dogs and cats. it also suffers attacks from mongooses, which are predators introduced into the area. it was thought to be extinct until several indivuals were discovered alive in 1974, 1975 and as recently as the year 2003. It possesses toxic saliva for protection.

One more creature whos existence was unknown was the La Palma Giant Lizard, Galliota auaritae. There are fewer than 50 mature indivuals left in the wild, and it is only found in Northern La Palma, Spain. It was extinct for 2000 years until its recent rediscovery in 2007, when some indivuals were found on a steep rock face of the Canary islands. This protected the lizards from their natural enemy, cats.

Though these are just a few of the creatures that were rediscovered, I feel that there are many more out there, waiting to be found and studied...

Different Parts of a Cell

Parts shown in the Plant cell diagram

Below is a list of the main parts shown in the plant cell diagram and the roles that they play in the cell.

Nucleus - contains the genetic information of the cell
Nuclear envelope - double membrane surrounding the nucleus
Perinuclear space - space between the two membranes of the nuclear envelope
Nucleolus - site of ribosome synthesis - densely granular
Chromatin - DNA-Protein Complex
Ribosomes - site of protein synthesis
Rough Endoplasmic Reticulum - covered in ribisomes - lamellar
Smooth Endoplasmic Reticulum - tubuler
Golgi Body - synthesis and secretion of polysaccharides
Chloroplast - Site of Photosynthesis
Granum (Grana) - stacked thyalkoid membranes
Stroma - fluid matrix surrounding the thylakoids
Thylakoid - Membrane found in the chloroplast
Intercellular air space - gap between cells
Cell Wall - Rigid structure surrounding plant cells, not present in animal cells
Middle lamella- protein rich cement between adjacent plant cell walls
Primary Cell Wall - earliest created cell walls - usually thin - found in young growing cells
Secondary Cell Wall - Formed in older cells as part of the differentiation process
Plasma Membrane - Outer boundary of the cell
Mitochrondrian - Energy producing organelle - respiration
Peroxisome- Removes hydrogens from substrates - present in photosynthetic cells - has a crystalline core
Oleosome - Oil lipid storage (seeds)
Vacuole - Water filled part of the cell that may represent up to 90% of the total plant cell - also contains ions, sugars, secondary metabolites and enzymes
Tonoplast - Membrane surrounding the Vacuole
An Explanation of the Key Cell Differences Between Plants and Animals

As plants are eukaryotic organisms, their cells have many similarities with other eukaryotic cells such as those found in animals. In spite of these similarities there are lots of ways in which animal and plant cells differ. Amongst the ways in which plant cells ablude from animal cells is the fact that they contain a fluid filled vacuole and have a hard outer wall; this is made of cellulose.

In addition to the cell walls and vacuoles another key difference between plant and animal cells is that they contain the chloroplast organelle; see plant cell diagram above. The chloroplast is the area of the plant that is involved in the conversion of light energy into starch through a process that is known as photosynthesis. Another plastid that is only found in plants is the amyloplast, this acts as a starch storage vessel.

The major differences between plant and animal cells are the presence of the cell wall, vacoules and chloroplast. As both animals and plants are eukaryotic organisms they also share many features within their cells, some of the organelles that they share include the nucleus, which contains the chromosomes and DNA; the ATP producing mitochondria; the protein processing golgi bodies and endoplasmic reticulum, and the 'liquid soup' cytoplasm.

It is these differences in plant cell make up that allows the plant to be such a successful sessile organism, for example it is the rigidity provided by the cellulose containing cell walls that give many plants the strength and support to grow to vast heights. The turgidity of a plants cell is provided by the liquid filled vessels that are the vacuoles. The chloroplast contains pigments known as chlorophyll, these appear to be green in colour; this is because they do not absorb green light, but that of red, far-red (Phytochromes) and blue. The eye than sees the reflected green light, it is this phenomenon that is responsible for the green colour of plant leaves. The process of photosynthesis takes place in the chloroplasts and allows the conversion of energy gathered from sunlight into starch through the use of carbon dioxide.

A plant contains specialised phloem cells, these enable the transport of signalling plant hormones and essential nutrients throughout the plant. In addition to the phloem, a plant has a transportation system known as the xylem; this system is formed from the lignification of cells to create xylem tissue, and is largely responsible for the transportation of water throughout a plant.

My learning from the above passage..

1. I learned about how a plant cell conducts photosynthesis through the use of chloroplasts.
2. I also learned how diverse the parts of a cell are. 
3. Finally, I also learned how plant cells aid in the plant's transport system.

Solar Powered Buggy

I have read an interesting article about how solar energy can powered up a Buggy from this source....


http://www.solarfeeds.com/ecofriend/14652-sanyo-panels-on-buggy-on-singapore-golf-course

Singapore golfers will soon be seen enjoying a green ride on solar Buggies. The owner of Marina Bay Golf Course is presently performing a feasibility trial in collaboration with Sanyo and Singapore Polytechnic by retrofitting a buggy with two solar panels to help charge the lead-acid battery required to power the vehicle. It is claimed that each solar buggy holds the potential to reduce carbon dioxide emissions by up to 280kg per year, while extending the battery life from 2.5 years to five years..

I have come across this website about overview of two different plant Cells namely . The article gives me a holistic view of the Plant Cell.

Two types of different Plant Cells.

The eukaryotic cell is composed of 4 main parts:

cell membrane - outer boundary of the cell
cytoplasm - jelly-like fluid interior of the cell
nucleus - the "control center" of the cell, contains the cell's DNA (chromosomes)
organelles - "little organs" that carry out cell functions





Prokaryotes are very simple cells, probably first to inhabit the earth.
Prokaryotic cells do not contain a membrane bound nucleus.
Bacteria are prokaryotes.
DNA of bacteria is circular.

The word "prokaryote" means "before the nucleus"

Different cells and their functions

There are many different cells in the body, and all of them are created to perform a specific duty or function. Here are some of the more commonly know cells:

The red blood cell. These are cells that are shaped like biconcave disks and they lack a nucleus and other common cell parts. Their duty is to deliver oxygen to other body parts via the blood flow in the circulatory system. They will pick up the oxygen from the lungs and then will release it while sqeezing through the capillaries. The cytoplasm of a red blood cell is rich in a chemical known as haemoglobin, which gives the blood its red colour and can bind oxygen to the cell.

Red blood cells are usually about six to eight microns in diameter.

The nerve cell, or neuron, is a cell that is electrically excitable and its function is to process and transmit information to the brain via electrical and chemical signalling. A typical nerve cell comprises a body, dendrites (filaments that arise from the cell body) and an axon (a special filament that also arises from the cell's body). Neurons are highly variable in size, and range from 4 microns to 100 microns.

The human egg cell is a gamete, or reproductive cell, that is produced by women in the ovaries. It is the largest cell in the human body, with a diameter of up to 120 microns and can be seen with the naked eye. When a sperm cell fuses with it, fertilisation occurs, and the fertilised egg becomes a zygote. It then starts to develop into a human foetus.

The sperm cell's name is derived from the Greek word sperma, meaning seed. It is an appropriate name, as the sperm is the seed that decides the sex of a baby after fertilasation of the egg cell. A sperm cell has a head, which contains a nucleus and chromosomes; many mitochondria, to aid in movement; and a tail that enables it to mive independently. Sperm cells have a head 5 microns by 3 microns, and a tail 41 microns long.

Cells (further info) (contd.)

A eukaryotic cell is at least 15 times larger than a prokaryotic cell. It is also up to 1000 times greater in volume. The eukaryotic cell is more complex, and contains specific parts that carry out specific functions. One thing that a eukaryotic cell has that a prokaryotic cell doesn't have is a nucleus that contains genetic material and DNA, and this is how the eukaryotic cell gets its name, as eukaryotic stands for "true nucleus".

Cells (further info)

There are actually not one, but two different types of cells: prokaryotic and eukaryotic.

A prokaryotic cell is simpler than the other type of animal cell, and is therefore smaller. It lacks a nucleus and other characteristics that are usually present in eukaryotic cells. Bacteria and archaea are two examples of prokaryotic cells.

As afore mentioned, a prokaryotic cell has a simpler architecture structure than its counterpart, with flagella and pili protruding from the cell's surface. Surrounding the cell is a cell envelope consisting of a cell wall and a plasma membrane. Inside this outer covering is the cell's cytoplasmic region, with DNA, ribosomes, and other inclusions.

Reflection on my Science Lessons (up to date)

These days, I find that I can remember facts better, and I can do my work without much trouble at all. So, I have high hopes for the next science test.

At the moment, I'm now starting on a new chapter in biology - cells. Originally, I always had problems trying to absorb facts and the lesson in general, as I was half asleep and could barely stay awake to listen to the lesson. So, it was no suprise when I failed my chemistry test.

However, now I am able to stay awake better, as I get sufficient sleep and can stay awake during lessons, even if they're boring. Therefore, I expect myself to be able to think better, and I should be able to score better for the coming tests.

Singapore's new aquatic science centre

I read up in the paper that the Straits Times sent reporters to the Aquatic Science Centre to see some of the state-of-the-art equipment that they use to develop eco-friendly and sustainable water management soutions.

This building, which is two-thirds the size of a soccer field, has many research facilities and structures, such as a 37.5 metre-long bio-flume that replicates near-natural conditions for scientists to study how organisms interact in a natural aquatic environment.

Even the structure contributes to the research of the scientists who work in the facility: the roof is built for collecting rainwater for analysis and research.

Through this article, I realise that there are actually people who care about the world's growing water crisis and are researching day and night to save it.

My Reflection on Science Lab sessions

So far, I'm quite enjoying my Science Lab sessions on Mondays. Though some of my experiments and practicals were a failure, such as the time when I tried to view cells under a microscope, or the time when I attempted chromatography of black ink.

However, some experiments went well, especially our first experiment for chemistry.

Therefore, I'd like to say that my science lessons have been fun, and, though my science results have been terrible, I'd like to continue doing such fun experiments during Monday lab sessions. 

My Reflection on my 'Gimli Glider' reflection

At first, I found it rather hard to rephrase the information I got. But, I evenually figured out how to make my ACE assignment sound interesting and convincing.

Cool science facts on animals

1. Of all the mammals, the order Chiroptera (bats) is the only group of mammals that possess true flight ability.

2. The beluga, Delphinapterus leucas, is also known as the sea canary due to the fact that it emits calls that can be heard through the hulls of boats.

3. The peregrine falcon, Falco peregrinus, is the world's fastest bird. It hits 230 kph when diving to catch prey.

4. The arctic tern, Sterna paradiscaca, makes the longest migration of any bird-16000 km, twice a year.

5. The king cobra, Ophiophagus hannah, is the longest venomous snake, at 5 metres long.

6. The blue coral snake, Maticora bivirgata, is also called the '100 pace snake', referring to the distance one is thought to be capable of traveling before succumbing to its venom.

7. The black mamba, Dendroaspis polylepis, is the world's fastest snake. In short bursts of speed it can reach 20 kph.

8. The whale shark is the largest fish in the world. It can reach lengths of 14 metres.

A little bit about myself

Hello to everyone who is viewing my blog. I'm Marcus, and this is my first attempt at creating a blog. My blog is also my e-portfolio for science, so you are free to view all my posts.