Saturday, November 6, 2010
Monday, August 23, 2010
bio (0823) - Gen: gene therapy
no teacher today, so did a bit of reading on my own.
genetic therapy is used to replace or correct genes that express negative traits.
it is mostly used for cancer cells, but can also be used to treat infectious diseases and hereditary diseases such as cystic fibrosis.
i was wondering how they go about inserting the genes to multiple cells, or if they insert it to one. it's quite genius actually, it's called trans.. something (LAWL i'll check later) and they use viruses to spread the new gene to other cells.
genius really.
genetic therapy is used to replace or correct genes that express negative traits.
it is mostly used for cancer cells, but can also be used to treat infectious diseases and hereditary diseases such as cystic fibrosis.
i was wondering how they go about inserting the genes to multiple cells, or if they insert it to one. it's quite genius actually, it's called trans.. something (LAWL i'll check later) and they use viruses to spread the new gene to other cells.
genius really.
phys (0823) - Med: spin moment
and with this, i make my triumphant return to note blogging.
so to begin with.. MRI stands for Magnetic Resonance Imaging, and it produces high resolution images.
it works on the basis of strong superconductors, they produce an immensely strong magnetic field (x30000 that of earth and x200 that of a fridge magnet) which is why hazards involved with MRI are caused by metal objects int he room (eg chairs) or if patients have metal plates in their body
alright so here we go:
atoms make up our body, and each atom is composed of smaller charged particles, which are constantly spinning. this spin creates a magnetic field along the axis (right hand grip rule), the spin moment.
in each nucleus, there are protons and neutrons, and this can occur with both. in an atom with an even amount of protons, the magnetic fields will cancel each other out (they face opposite directions because it is energetically favourable) in an atom with an odd number, they all pair up, the remaining field is the net magnetic field. (mind you this occurs with neutrons as well, but they cannot pair up with protons)
now usually, all the net magnetic fields go off in different directions, but when placed in the superconductor magnetic field, they mostly all align in the same direction, at a slight angle, and it rotates in the direction of its axis around the magnetic field, ie. it precesses.
err yeah i think that's all for now on that.
so to begin with.. MRI stands for Magnetic Resonance Imaging, and it produces high resolution images.
it works on the basis of strong superconductors, they produce an immensely strong magnetic field (x30000 that of earth and x200 that of a fridge magnet) which is why hazards involved with MRI are caused by metal objects int he room (eg chairs) or if patients have metal plates in their body
alright so here we go:
atoms make up our body, and each atom is composed of smaller charged particles, which are constantly spinning. this spin creates a magnetic field along the axis (right hand grip rule), the spin moment.
in each nucleus, there are protons and neutrons, and this can occur with both. in an atom with an even amount of protons, the magnetic fields will cancel each other out (they face opposite directions because it is energetically favourable) in an atom with an odd number, they all pair up, the remaining field is the net magnetic field. (mind you this occurs with neutrons as well, but they cannot pair up with protons)
now usually, all the net magnetic fields go off in different directions, but when placed in the superconductor magnetic field, they mostly all align in the same direction, at a slight angle, and it rotates in the direction of its axis around the magnetic field, ie. it precesses.
err yeah i think that's all for now on that.
Thursday, June 17, 2010
ag (0617) - SFP: water management
water quality is an issue, things to look out for are sediment runoff, excessive nutrients eg. from animal waste or fertilizers, salinity problems and pesticide runoff.
water quantity is an issue especially during times of drougt. irrigation has to be carefully planned, since if done irresponsibly, a majority of the water can be lost through evaporation.
government legislations are put into place to help manage the use of water. water licenses are required to extract water from catchments, but it's allocations that matter. allocations dictate how much water a farmer can use during a year based on their license. sometimes they might not be allocated any at all, but have to pay license fees anyway
water quantity is an issue especially during times of drougt. irrigation has to be carefully planned, since if done irresponsibly, a majority of the water can be lost through evaporation.
government legislations are put into place to help manage the use of water. water licenses are required to extract water from catchments, but it's allocations that matter. allocations dictate how much water a farmer can use during a year based on their license. sometimes they might not be allocated any at all, but have to pay license fees anyway
phys (0617) - ItI: thomson's experiment
the aim of thomson's experiment was to determine the ratio of charge to mass in cathode rays.
his apparatus was a cathode ray tube with a screen, and he had both an electric field and a magnetic field to focus the cathode rays. with this he found the velocity of the rays, knowing that:
for electric fields:
F = qE
for magnetic fields:
F = qvB
therefore
qE = qvB
v = E/B
when these weren't there, however, he noticed that the rays produced a circular pattern, and he concluded that this was due to a centripetal force.
knowing
F = (mv^2)/r = qE = qvB
he could determine the ratio, ie. m/q
after testing this with different metals in the cathode, he discovered that the ratio was always the same, which proved that the negative particles within the cathode ray were the same for all metals, and later it was concluded that it was the same for all materials.
this was the introduction of the term, electron
his apparatus was a cathode ray tube with a screen, and he had both an electric field and a magnetic field to focus the cathode rays. with this he found the velocity of the rays, knowing that:
for electric fields:
F = qE
for magnetic fields:
F = qvB
therefore
qE = qvB
v = E/B
when these weren't there, however, he noticed that the rays produced a circular pattern, and he concluded that this was due to a centripetal force.
knowing
F = (mv^2)/r = qE = qvB
he could determine the ratio, ie. m/q
after testing this with different metals in the cathode, he discovered that the ratio was always the same, which proved that the negative particles within the cathode ray were the same for all metals, and later it was concluded that it was the same for all materials.
this was the introduction of the term, electron
Wednesday, June 16, 2010
ag (0616) - SFP: land capability system
the land capability system is a method of classification for land for agricultural use.
it ranges from class I to class VIII,
with class I to III suitable for cultivation
IV to VI suitable for grazing
and VII and VIII not suitable at all.
check table on sheet for details on each class.
the land is classified based on factors such as climate, soil, fertility, slope and drainage
knowledge of the land capability helps in making decisions about the practices done on the land, for example methods of cultivation (minimum till etc)
it ranges from class I to class VIII,
with class I to III suitable for cultivation
IV to VI suitable for grazing
and VII and VIII not suitable at all.
check table on sheet for details on each class.
the land is classified based on factors such as climate, soil, fertility, slope and drainage
knowledge of the land capability helps in making decisions about the practices done on the land, for example methods of cultivation (minimum till etc)
math (0616) - E&LF: differentiation of expontentials
the important thing to remember, is that the derivative of e, is e. basically.
y = e^f(x)
y' = e^f(x) * f'(x)
notes are proably not the best way of studying maths
y = e^f(x)
y' = e^f(x) * f'(x)
notes are proably not the best way of studying maths
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