Learn the basic introductory about Waves.
Key Slides & Points:
1. Intro
2. Definition
3. Appearance & Behaviour
4. Types of Waves
5. Parts of a Wave
6. Dimensional Waves
An overview of travelling waves and calculating wave speed.There are many different forms of speed including transverse and longitudinal waves. Examples are primary and secondary waves. I used powerpoint to present my learning objective.
An overview of travelling waves and calculating wave speed.There are many different forms of speed including transverse and longitudinal waves. Examples are primary and secondary waves. I used powerpoint to present my learning objective.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
2. WAVES? You mean the movement of
flags?
No, No, a wave is not just the movement of a flag or any
other thing. It’s a sort of disturbance which carries
energy and momentum.
Sir, I still don’t get it. I’m
bad at physics. Can you
please explain it in detail.
Sure, no problem, let’s begin
students!
3. Imagine that you’re near a pond/lake and you’re throwing
pebbles/stones into it.
What do you observe?
After the stone is dropped, you can see concentric circles
moving around the point where the stone was thrown.
These concentric circles are called ripples, and
they would look something like this…
4. Thus, as you can see, the surface of the water is disturbed by
the stone throw. If you continue to throw stones, you can
observe that the ripples move outward along a circle.
You may feel that the water is moving outward from the disturbed surface,
but actually the water doesn’t move at all.
In fact, it just moves Up & Down.
So we can say that a moving disturbance is created, rather than any real
propagation of the water.
5. Thus, patterns such as ripples on the surface of water, which move
without the actual transfer or flow of matter as a whole, are called
waves.
Wow! So much to know about waves!
I want to know more!
Sure! and now, let’s learn about what they do, how
they look, and how many types of waves are there….
Waves transport energy & the pattern of disturbance has
information that propagate from one point to another
Well? What do you think students?
6. But Sir, how does a wave look like?
Let us do a small experiment to ‘see’ how a wave looks like:
Consider a collection of springs connected to one another as shown:
If the spring k3 is pulled and released suddenly, the disturbance travels to the other end.
It is observed that each string is pulled;k3 pulls k2 which in turn pulls k1, thereby
propagating the disturbance.
7. Is there more than just one type of wave?
Waves are of three types:
1. Mechanical Waves – Waves which require material medium to propagate
Examples : Sound waves, seismic waves, ripples on surface of water
2. Non-Mechanical Waves (Electromagnetic waves) - Waves which don’t require a
material medium to propagate. Examples: Light, Radio Waves, Ultra-violet waves
3. Matter Waves – Waves associated with the constituents of matter.
For now, we shall learn in detail about Mechanical Waves…
8. Mechanical Waves
Waves which require a material medium to propagate.
Sound waves
Ripples on the surface of water
Seismic waves
9. Transverse Waves
Transverse Waves:
Waves whose vibrations of the particles are perpendicular to the direction of
propagation of the wave, are called Transverse waves. Examples: Light waves, radio
waves etc.
10. Longitudinal Waves
Longitudinal Waves:
Waves whose vibrations of the particles are parallel to or along the direction of
propagation of the wave, are called Longitudinal waves. Examples: Sound waves,
Seismic waves etc
11. How do these waves behave?
Mechanical waves are related to the elastic property of the medium.
In Transverse waves, the constituents of the medium oscillate perpendicular
to the wave motion causing change in shape, hence they’re subject to
shearing stress.
Fluids have no shape, and thus they only yield to shearing stress.
This is the reason why transverse waves are not possible in solids & strings,
but not in fluids.
Longitudinal waves possess both bulk & sheer elastic moduli and can travel
longitudinal as well as transverse waves.
12. Basic parts of a wave
The maximum displacement of a wave from it’s equilibrium position (initial position) is
called the Amplitude of the wave.
On a plane, the maximum displacement along the positive y-axis is called the Crest,
whereas the maximum displacement along the negative y-axis is called the Trough.
The distance between two consecutive Troughs, or two consecutive Crests is called
Wavelength.
13. Dimensional Waves: One Dimensional Wave
Waves which travel along a straight line are called One-dimensional Waves.
The most basic One Dimensional Wave is the Sine Wave or Sinusoidal Wave.
Another example of One Dimensional Waves are the waves produced on a Stretched String.
Sine Wave
Wave on stretched string
14. Dimensional Waves: Two Dimensional Wave
Waves which travel along a plane are called Two-dimensional Waves.
On the plane, these waves travel along both the x-axis & the y-axis.
These waves look like this…
A two-dimensional wave on a disk in
normal mode
Dispersion of light is a two-dimensional wave.
15. Dimensional Waves: Three Dimensional Wave
Waves which travel in space, in all three dimensions are called Three-dimensional Waves.
Sound is a good example for a three-dimensional wave.
Electromagnetic Wave is a special wave in which two waves (electric & magnetic waves) travel
perpendicular to each other and propagate forward simultaneously, together travelling in three-
dimensions.
Three-dimensional
propagation of sound
waves
Three-dimensional
propagation EM Waves
16. Dimensional Waves: Stationary Waves
A standing wave, also known as a stationary wave, is a wave that remains in a constant
position.
This phenomenon can occur because the medium is moving in the opposite direction
to the wave, or;
it can arise in a stationary medium as a result of interference between two waves
traveling in opposite directions;
In another case, for waves of equal amplitude traveling in opposing directions, there is,
on an average, no net propagation of energy.
17. Dimensional Waves: Shock Waves
A shock wave (also called shock front or simply "shock") is a type of propagating
disturbance. Like an ordinary wave, it carries energy and can propagate through a
medium or in some cases in the absence of a material medium, through a filed such as
the electromagnetic field.
A shock wave travels through most media at a higher speed than an ordinary wave.
A shock wave produced by a supersonic body (jet)Shadowgraph of a shock wave produced by a
supersonic bullet
18. Matter Waves: de Broglie’s Waves
The Schrödinger equation describes the wave-like
behaviour of particles in quantum mechanics. Using his
theories, Louis de Broglie postulated that all particles
with momentum have a wavelength
𝝀 =
𝒉
𝒑
where h is Planck's constant, and p is the magnitude of
the momentum of the particle, and 𝛌 is the wavelength of the
wave, now-a-days called as the de Broglie’s wavelength.
de Broglie’s wave propagation
19. Sound Waves
As waves passes through air, it compresses and expands a small region of air, called
Compressions & Rarefactions, respectively.
This causes a change in density ∆𝛒 and induces a change in pressure ∆𝐩 in that region.
These changes disturb the air molecules, thereby propagating the disturbance and thus
producing sound.
20. Wow! I learnt so much today…All about waves! I am so much interested in
waves that I want to learn more.
Hmm But you have learnt enough for today. We’ll resume
next time
Hope you enjoyed my teaching!
Have a nice day!