This document discusses simple machines and the concept of work. It defines work as the product of the applied force and the distance moved in the direction of the force. The six simple machines - lever, wheel and axle, pulley, inclined plane, wedge, and screw - are introduced. These machines allow a smaller input force to overcome a larger resistive force, providing mechanical advantage. The document provides examples and formulas for calculating the mechanical advantage of each machine type. It also discusses related concepts like efficiency and power.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
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 .
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
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.
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.
2. 2
What is work?
In science, the word work has a
different meaning than you may be
familiar with.
The scientific definition of work is:
using a force to move an object a
distance (when both the force and the
motion of the object are in the same
direction.)
3. 3
Work or Not?
According to the
scientific definition,
what is work and
what is not?
a teacher lecturing
to her class
a mouse pushing a
piece of cheese with
its nose across the
floor
4. 4
Work or Not?
According to the
scientific definition,
what is work and
what is not?
a teacher lecturing
to her class
a mouse pushing a
piece of cheese with
its nose across the
floor
6. 6
What’s work?
A scientist delivers a speech to an
audience of his peers.
A body builder lifts 350 pounds above
his head.
A mother carries her baby from room
to room.
A father pushes a baby in a carriage.
A woman carries a 20 kg grocery bag
to her car?
7. 7
What’s work?
A scientist delivers a speech to an
audience of his peers. No
A body builder lifts 350 pounds above
his head. Yes
A mother carries her baby from room
to room. No
A father pushes a baby in a carriage. Yes
A woman carries a 20 km grocery bag
to her car? No
8. 8
Formula for work
Work = Force x Distance
The unit of force is newtons
The unit of distance is meters
The unit of work is newton-meters
One newton-meter is equal to one joule
So, the unit of work is a joule
9. 9
W=FD
Work = Force x
Distance
Calculate: If a man
pushes a concrete
block 10 meters
with a force of 20 N,
how much work has
he done?
10. 10
W=FD
Work = Force x
Distance
Calculate: If a man
pushes a concrete
block 10 meters
with a force of 20 N,
how much work has
he done? 200 joules
(W = 20N x 10m)
11. 11
Power
Power is the rate at which work is
done.
Power = Work*/Time
*(force x distance)
The unit of power is the watt.
12. 12
Check for Understanding
1.Two physics students, Ben and Bonnie, are
in the weightlifting room. Bonnie lifts the 50
kg barbell over her head (approximately .60
m) 10 times in one minute; Ben lifts the 50
kg barbell the same distance over his head
10 times in 10 seconds.
Which student does the most work?
Which student delivers the most
power?
Explain your answers.
13. 13
Ben and Bonnie do
the same amount of
work; they apply the
same force to lift the
same barbell the same
distance above their
heads.
Yet, Ben is the
most powerful since he
does the same work in
less time.
Power and time are
inversely proportional.
14. 14
2. How much power will it take to
move a 10 kg mass at an acceleration
of 2 m/s/s a distance of 10 meters in 5
seconds? This problem requires you to
use the formulas for force, work, and
power all in the correct order.
Force=Mass x Acceleration
Work=Force x Distance
Power = Work/Time
15. 15
2. How much power will it take to move a 10 kg
mass at an acceleration of 2 m/s/s a distance of 10
meters in 5 seconds? This problem requires you to
use the formulas for force, work, and power all in
the correct order.
Force=Mass x Acceleration
Force=10 x 2
Force=20 N
Work=Force x Distance
Work = 20 x 10
Work = 200 Joules
Power = Work/Time
Power = 200/5
Power = 40 watts
16. 16
History of Work
Before engines and motors were invented, people
had to do things like lifting or pushing heavy loads by
hand. Using an animal could help, but what they really
needed were some clever ways to either make work
easier or faster.
17. 17
Simple Machines
Ancient people invented simple
machines that would help them overcome
resistive forces and allow them to do the
desired work against those forces.
18. 18
Simple Machines
The six simple machines are:
Lever
Wheel and Axle
Pulley
Inclined Plane
Wedge
Screw
19. 19
Simple Machines
A machine is a device that helps make
work easier to perform by
accomplishing one or more of the
following functions:
transferring a force from one place to
another,
changing the direction of a force,
increasing the magnitude of a force, or
increasing the distance or speed of a
force.
20. 20
Mechanical Advantage
It is useful to think about a machine in
terms of the input force (the force you
apply) and the output force (force
which is applied to the task).
When a machine takes a small input
force and increases the magnitude of
the output force, a mechanical
advantage has been produced.
21. 21
Mechanical Advantage
Mechanical advantage is the ratio of output force
divided by input force. If the output force is bigger
than the input force, a machine has a mechanical
advantage greater than one.
If a machine increases an input force of 10 pounds
to an output force of 100 pounds, the machine has a
mechanical advantage (MA) of 10.
In machines that increase distance instead of force,
the MA is the ratio of the output distance and input
distance.
MA = output/input
22. 22
No machine can increase
both the magnitude and the
distance of a force at the
same time.
23. 23
The Lever
A lever is a rigid bar
that rotates around a
fixed point called the
fulcrum.
The bar may be either
straight or curved.
In use, a lever has both
an effort (or applied)
force and a load
(resistant force).
24. 24
The 3 Classes of Levers
The class of a lever
is determined by the
location of the
effort force and the
load relative to the
fulcrum.
26. 26
To find the MA of a lever, divide the output force by the input force, or
divide the length of the resistance arm by the length of the effort arm.
27. 27
First Class Lever
In a first-class lever the fulcrum is
located at some point between the
effort and resistance forces.
Common examples of first-class levers
include crowbars, scissors, pliers, tin
snips and seesaws.
A first-class lever always changes the
direction of force (I.e. a downward effort
force on the lever results in an upward
movement of the resistance force).
28. 28
Fulcrum is between EF (effort) and RF (load)
Effort moves farther than Resistance.
Multiplies EF and changes its direction
29. 29
Second Class Lever
With a second-class lever, the load is
located between the fulcrum and the effort
force.
Common examples of second-class levers
include nut crackers, wheel barrows, doors,
and bottle openers.
A second-class lever does not change the
direction of force. When the fulcrum is
located closer to the load than to the effort
force, an increase in force (mechanical
advantage) results.
30. 30
RF (load) is between fulcrum and EF
Effort moves farther than Resistance.
Multiplies EF, but does not change its direction
31. 31
Third Class Lever
With a third-class lever, the effort
force is applied between the fulcrum
and the resistance force.
Examples of third-class levers include
tweezers, hammers, and shovels.
A third-class lever does not change the
direction of force; third-class levers
always produce a gain in speed and
distance and a corresponding decrease in
force.
32. 32
EF is between fulcrum and RF (load)
Does not multiply force
Resistance moves farther than Effort.
Multiplies the distance the effort force travels
33. 33
Wheel and Axle
The wheel and axle is a
simple machine
consisting of a large
wheel rigidly secured
to a smaller wheel or
shaft, called an axle.
When either the wheel
or axle turns, the other
part also turns. One full
revolution of either part
causes one full
revolution of the other
part.
34. 34
Pulley
A pulley consists of a grooved wheel
that turns freely in a frame called a
block.
A pulley can be used to simply change
the direction of a force or to gain a
mechanical advantage, depending on
how the pulley is arranged.
A pulley is said to be a fixed pulley if it
does not rise or fall with the load being
moved. A fixed pulley changes the
direction of a force; however, it does not
create a mechanical advantage.
A moveable pulley rises and falls with
the load that is being moved. A single
moveable pulley creates a mechanical
advantage; however, it does not change
the direction of a force.
The mechanical advantage of a
moveable pulley is equal to the number
of ropes that support the moveable
pulley.
35. 35
Inclined Plane
An inclined plane is
an even sloping
surface. The
inclined plane
makes it easier to
move a weight from
a lower to higher
elevation.
36. 36
Inclined Plane
The mechanical
advantage of an
inclined plane is equal
to the length of the
slope divided by the
height of the inclined
plane.
While the inclined plane
produces a mechanical
advantage, it does so
by increasing the
distance through which
the force must move.
37. 37
Although it takes less force for car A to get to the top of the ramp,
all the cars do the same amount of work.
A B C
38. 38
Inclined Plane
A wagon trail on a
steep hill will often
traverse back and forth
to reduce the slope
experienced by a team
pulling a heavily loaded
wagon.
This same technique is
used today in modern
freeways which travel
winding paths through
steep mountain passes.
39. 39
Wedge
The wedge is a modification
of the inclined plane.
Wedges are used as either
separating or holding
devices.
A wedge can either be
composed of one or two
inclined planes. A double
wedge can be thought of as
two inclined planes joined
together with their sloping
surfaces outward.
40. 40
Screw
The screw is also a
modified version of
the inclined plane.
While this may be
somewhat difficult
to visualize, it may
help to think of the
threads of the
screw as a type of
circular ramp (or
inclined plane).
41. 41
MA of an screw can be calculated by dividing the number of
turns per inch.
43. 43
Efficiency
We said that the input force times the distance equals
the output force times distance, or:
Input Force x Distance = Output Force x Distance
However, some output force is lost due to friction.
The comparison of work input to work output is called
efficiency.
No machine has 100 percent efficiency due to friction.
44. 44
Practice Questions
1. Explain who is doing more work and why: a bricklayer
carrying bricks and placing them on the wall of a building
being constructed, or a project supervisor observing and
recording the progress of the workers from an observation
booth.
2. How much work is done in pushing an object 7.0 m across a
floor with a force of 50 N and then pushing it back to its
original position? How much power is used if this work is done
in 20 sec?
3. Using a single fixed pulley, how heavy a load could you lift?
45. 45
Practice Questions
4. Give an example of a machine in which friction is
both an advantage and a disadvantage.
5. Why is it not possible to have a machine with 100%
efficiency?
6. What is effort force? What is work input? Explain
the relationship between effort force, effort
distance, and work input.
46. 46
Practice Questions
1. Explain who is doing more work and why: a bricklayer carrying
bricks and placing them on the wall of a building being constructed,
or a project supervisor observing and recording the progress of the
workers from an observation booth. Work is defined as a force
applied to an object, moving that object a distance in the direction of
the applied force. The bricklayer is doing more work.
2. How much work is done in pushing an object 7.0 m across a floor
with a force of 50 N and then pushing it back to its original position?
How much power is used if this work is done in 20 sec? Work = 7 m
X 50 N X 2 = 700 N-m or J; Power = 700 N-m/20 sec = 35 W
3. Using a single fixed pulley, how heavy a load could you lift?Since a
fixed pulley has a mechanical advantage of one, it will only change
the direction of the force applied to it. You would be able to lift a load
equal to your own weight, minus the negative effects of friction.
47. 47
Practice Questions
4. Give an example of a machine in which friction is both an advantage
and a disadvantage. One answer might be the use of a car jack.
Advantage of friction: It allows a car to be raised to a desired height
without slipping. Disadvantage of friction: It reduces efficiency.
5. Why is it not possible to have a machine with 100% efficiency?
Friction lowers the efficiency of a machine. Work output is always
less than work input, so an actual machine cannot be 100% efficient.
6. What is effort force? What is work input? Explain the relationship
between effort force, effort distance, and work input. The effort force
is the force applied to a machine. Work input is the work done on a
machine. The work input of a machine is equal to the effort force
times the distance over which the effort force is exerted.