Newton's laws of motion are three physical laws that, together, laid the foundation for classical mechanics. They describe the relationship between a body and the forces acting upon it, and its motion in response to those forces.
According to Newton's
second law...
Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).
What does this mean?
Everyone unconsiously knows the Second Law. Everyone knows that heavier objects require more force to move the same distance as lighter objects.
However, the Second Law gives us an exact relationship between force, mass, and acceleration. It can be expressed as a mathematical equation:
FORCE = MASS times ACCELERATION
Newton's second law of motion explains how an object will change velocity if it is pushed or pulled upon.
Firstly, this law states that if you do place a force on an object, it will accelerate (change its velocity), and it will change its velocity in the direction of the force. So, a force aimed in a positive direction will create a positive change in velocity (a positive acceleration). And a force aimed in a negative direction will create a negative change in velocity (a negative acceleration).
Secondly, this acceleration is directly proportional to the force. For example, if you are pushing on an object, causing it to accelerate, and then you push, say, three times harder, the acceleration will be three times greater.
According to Newton's
second law...
Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).
What does this mean?
Everyone unconsiously knows the Second Law. Everyone knows that heavier objects require more force to move the same distance as lighter objects.
However, the Second Law gives us an exact relationship between force, mass, and acceleration. It can be expressed as a mathematical equation:
FORCE = MASS times ACCELERATION
Newton's second law of motion explains how an object will change velocity if it is pushed or pulled upon.
Firstly, this law states that if you do place a force on an object, it will accelerate (change its velocity), and it will change its velocity in the direction of the force. So, a force aimed in a positive direction will create a positive change in velocity (a positive acceleration). And a force aimed in a negative direction will create a negative change in velocity (a negative acceleration).
Secondly, this acceleration is directly proportional to the force. For example, if you are pushing on an object, causing it to accelerate, and then you push, say, three times harder, the acceleration will be three times greater.
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 pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
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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 .
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.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
3. • Newton’s first law of motion describes how an object at
rest will stay at rest. It also describes how moving object
at constant velocity stays in motion. In both cases, force
influences an object’s motion. What characteristics of an
object makes it harder to stop?
4. • The first law of motion is the law of inertia. It states that:
• An object at rest stays at rest, and an object in
stays in motion at constant velocity unless acted
by a net external force.
5. • Inertia is the tendency of an object to resist motion. For objects at rest, inertia depends on
mass. The larger the object, the larger is the inertia.
• For moving objects, inertia depends on the object’s momentum. The greater the
of an object, the harder it is to stop from moving.
6. EXAMPLE
• Let us consider a pool ball set on the table. Before a strike from another
ball or the cue stick, the pool balls are at rest. It will remain at rest as long
as no external force will act on it. When the cue ball has been struck, the
cue ball will continue to move with constant velocity as long as no
external force acts on it.
7.
8.
9.
10.
11.
12. NEWTON'S SECOND LAW OF
MOTION
• If you are asked to push a 1kg box and a boulder, it will be easier for you to move
a 1kg box compared to the boulder at the same distance. Moving the boulder will
require greater amount of force compared to moving a 1kg box.
• How is mass, force, and the acceleration of an object related to each other?
13. LEARN ABOUT IT!
• The second law of motion is the law of acceleration. It
states that:
• The acceleration is produced when a net force acts on
mass, and that acceleration is directly proportional to
the force acting on the object and inversely proportional
to the object's mass.
14. •Newton's second law could be
mathematically written as
•F=ma
•where a is the acceleration in (m/s2), F is
the force in newton (N), m is the mass
in kilograms (kg).
•The equation is also commonly written as
•F=ma.
15.
16. EXAMPLE 1
•How much force is needed to accelerate a 75 kg
object at a rate of 5 m/s2?
17. EXAMPLE 2
•How much force is needed to accelerate a 60 kg
object at a rate of 2.5 m/s2?
18. EXAMPLE 3
•Chris wanted to move a 5 kg box across the hall. To
do this, he applied 50 N of force. What is the
acceleration of the box?
19. EXAMPLE 4
•A physics book with a mass of 1.5 kg was moved
across a table by a 45 N force. What is the
acceleration of the book?
20. EXAMPLE 5
•A 6.125 N force caused a ball to accelerate at 9.8
m/s2. What is the mass of the ball in grams?
21. EXAMPLE 6
•A 4800 N force acts on a car at rest and causes it to
accelerate at 2.4m/s2.What is the mass of the car in
grams
22. FORCE AND ACCELERATION
• The first part of the second law tells that the greater the
unbalanced force, the greater the acceleration of the body being
acted upon. If the force F1 is applied to a body at one time and a
force F2 at another time, then
• F1/a1=F2/a2
23. EXAMPLE 7
•A force of 5.0 N accelerates an object by 2.0 m/s2.
what force is needed to give the same object an
acceleration of 3.4 m/s2.
24. EXAMPLE 8
•Two forces of magnitudes 6.0 N and 4.0 N act on a
3.2 kg body. What is the acceleration produced
when these forces are acting in the same direction?
What is the acceleration produced when these
forces are oppositely directed?
26. MOMENTUM
• is a quantity that describes an object's resistance to
stopping (a kind of "moving inertia").
• is represented by the symbol p (boldface).
• is the product of an object's mass and velocity.
• p = mv
• is a vector quantity (since velocity is a vector and mass
is a scalar).
27. IMPULSE
•is a quantity that describes the effect of a net force
acting on an object (a kind of "moving force").
•is represented by the symbol J (boldface).
•is the product of the average net force acting on an
object and its duration.
•J=Ft
28. RECALL
• a=vf-vi/t
• Substituting in the equation F=ma
• Ft-mvi-mvf
• This equation tells us that a net force F acts on the
body, the impulse of the net force is equal to the
change in momentum of the body. The statement is
called the impulse-momentum theorem, which is
considered as an alternative statement of Newton’s
second law of motion.
29. EXAMPLE 9
• An air bag increases impact time to reduce the force
experienced by a driver of a car during collision. A bus hit
a car, which is parked on the road, from behind. The car
accelerates to 4.5 m/s in 0.15s. a.) What force does the
driver of the car experience is he is not wearing a seat
belt during the accident? Assume that the combined
mass of the car and driver is 2580 kg. b. If the car has an
air bag and crumple zones increase the impact time t 0.45
s, what force is experienced by the driver?
30. NEWTON'S THIRD LAW OF
MOTION
• Newton’s third law of motion explains how objects interact with each
other in terms of forces. The third law of motion is also called the law of
interaction. It states that:
• For every action, there is an equal and opposite reaction.
• When a force acts on an object, another force reacts. The two forces
that act and reacts are called action-and-reaction forces. The three
characteristics of an action-and-reaction force are:
1. equal in magnitude,
2. opposite in direction, and
3. acting on different objects.
31. EXAMPLE
• The action force is the force on the table due to the weight of the book. In return,
the table reacts by applying a force in the book that is equal in magnitude but
opposite in direction.
Momentum( p=mv)- it is a vector quantity, having the same direction as velocity.
Impulse(J=Ft)- is the product f the force and time during which the force act. It is a vector quantity with same direction as the force.
Suppose the book is now sliding across the tabletop, say to the right. The forces acting on the ball are illustrated in figure 5. The downward gravitational force is balanced by the normal force. As the book slides to the right, friction acts to slow the movement of the book. There is no force that is acting to balance friction. Hence, there is an unbalanced force acting on the book. In accordance to Newton’s first law, there is an unbalanced force acting on the book. As such, the book will change its state of motion and will slow down.
● When a car at rest or in constant velocity suddenly accelerates forward, you feel as if a force is pulling you backwards. In actuality, inertia is making your body want to stay in its state of motion as the car accelerates forward.
● A hockey puck will continue to slide across a frictionless ice until acted upon by an unbalanced external force.
● A skateboarder will fly forward off the board when hitting an obstacle or an object that stops its motion.