A lesson designed for Italian students in the last year of Upper Secondary School (18 year old) who study Physics in English (CLIL).
How the knowledge of the atom structure developed in the early XIX century and the main experiments that allowed scientists to discover it are explained.
Bohr's Theory is based on an early model of atom where electrons travel round the nucleus in a discrete stable numbers of orbit determined by Quantum conditions. This is an extension of Rutherford Model of atom.
Introduction
Discovery of Sub-atomic Particles
Atomic Models
Developments leading to Bohr’s Model of atom
Bohr’s Model for Hydrogen atom
Quantum Mechanical Model of the atoms
Bohr's Theory is based on an early model of atom where electrons travel round the nucleus in a discrete stable numbers of orbit determined by Quantum conditions. This is an extension of Rutherford Model of atom.
Introduction
Discovery of Sub-atomic Particles
Atomic Models
Developments leading to Bohr’s Model of atom
Bohr’s Model for Hydrogen atom
Quantum Mechanical Model of the atoms
This presentation is specially made for the students of grades 11 and 12 of High School. This is the presentation of chapter Atomic Structure with proper diagrams, figures, facts, mnemonics, and some repeated past questions. Here you will get a chance to know about Atomic theory, Daltons Law, particles and so on.
Secondary Education
Chemistry
Chapter 1
Lesson 1
if you have any question don't hesitate to contact me
join the facebook group
http://www.facebook.com/#!/group.php?gid=17663120872&v=info
Best of luck
Mr.Ehab Mohamed
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.
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.
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 .
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.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
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.
Richard's aventures in two entangled wonderlandsRichard 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.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
1. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” ModicaCLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
Atomic Spectra and
Models of the Atom
LEARNING OBJECTIVE
• To know the relationship between atomic
spectra and the electronic structure of
atoms.
• To understand how scientific models
develop.
2. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” ModicaCLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
Atomic Spectra and Models
of the Atom
3. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” ModicaCLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
Do you know…
• … what is an atom?
• … what are atoms made of?
• … how/when were the atom components
discovered?
• …what is the light spectrum?
4. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” ModicaCLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
FIRST DISCOVERIES
• 1897 Joseph John Thomson (1856-1940)
discovered the electron, experimentally
determining its charge to mass ratio
e/m =1.7591011 C/kg and concluded that they
are a component of every atom.
• 1909 Robert Millikan (1868-1953) - Oil drop
experiment - determined the charge and the mass
of an electron.
e =1.602 10-19 C m = 9.11 10-31 kg
7. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
THOMSON’S MODEL (1902)
Plum Pudding Model
Electrons are surrounded by a
soup of positive charge to
balance the electrons negative
charges,
like negatively charged "plums"
surrounded by positively
charged "pudding"
8. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
The Gold Foil Experiment
Rutherford, Geiger & Marsden (1911):
The Gold Foil Experiment
“ It was almost as incredible as if you fired
a 15-inch shell at a piece of tissue paper
and it came back and hit you.”
10. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
RUTHERFORD MODEL (1911)
An atom contains a
small dense positive
charge surrounded by
negatively charged
electrons revolving
around the positive
charge just like planets
orbit the sun.
11. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” ModicaCLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
But…
An accelerating charged particle emits
electromagnetic radiation
The orbiting electron has centripetal acceleration
It looses energy
The orbit radius decreases
The electron falls onto the nucleus in about 10-11s
The atom is not stable
12. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
What do you know so far?
• Who discovered the electron?
• What is the plum-pudding model?
• Why was the Rutherford’s “gold foil”
experiment outcome surprising?
• What is new in Rutherford’s model?
• Why wasn’t it a suitable model?
13. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” ModicaCLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
FROM CLASSICAL TO QUANTUM
PHYSICS
When you try to apply the classical mechanics
(Newton’s) laws to microscopic objects –
such as atoms and the e.m. waves they emit –
you come to contradictions with experience.
Therefore the fundamental dynamics’ and
electromagnetism’ laws have to be changed
so that the new laws correctly describe
microscopic phenomena, but reduce to
classical laws when applied to macroscopic
objects.
“Correspondence Principle” – Niels Bohr
14. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
BOHR MODEL
The electrons move about
the nucleus in "stationary
states" which are stable,
NOT radiating energy.
Each orbit can hold no
more than 2 electrons.
(Pauli’s Exclusion
Principle, 1925)
15. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” ModicaCLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
ELECTRONIC TRANSITIONS
An electron is able to
absorb or emit energy
in order to “jump” from one to the other
orbit.
But what is it exchanging energy with?
16. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
The photon (1905)
Some metals emit electrons
when light shines on them:
the brighter the light,
the more electrons.
Einstein (1905) explained the
effect by describing light as a
bundle of particles, or
photons.
A photon gives a quantum of
energy depending on its
frequency/wavelenght
(colour)
E = hf = hc/.
Jsh 34
1063.6
17. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
COMPTON EFFECT (1923)
If a photon has high energy (X-rays), the electron is given
enough energy to be completely ejected from its atom,
and a photon containing the remaining energy (smaller
frequency) is scattered in a different direction from the
original.
LIGHT = PARTICLE (PHOTON)
18. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
ABSORPTION
An atom can absorb a photon
of light, so that an electron
“jumps” to an orbit that has a
higher energy.
This can only happen if the
photon energy equals the
difference in energy between
the two states
DE = h f
Jsh 34
1063.6
19. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
EMISSION
When an atom in an excited
state undergoes a transition
to the ground state, it loses
energy by emitting a
photon whose energy
corresponds to the
difference in energy
between the two states
DE = h f
Jsh 34
1063.6
20. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
What do you know so far?
• What is new in Bohr’s model?
• What is the light made of?
• How can an atom absorb/emit energy?
• How much energy can the atom
absorb/emit?
21. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
HYDROGEN BOHR’S ATOM
• Allowed orbits are labeled
with the integer n
(quantum number) from
the inner to the outer one
• Orbits have increasing
radius, proportional to the
integer number n2
• The electron energy is
proportional to 1/n2
22. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
HYDROGEN SPECTRUM
• Because each atom has a unique set of orbits,
• it has a unique set of energy differences and so
• it emits or absorbs a unique set of wavelengths,
• that is called the fingerprint of the element.
23. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
HYDROGEN SPECTRUM
• Each colour of the spectrum has different wavelength,
• so it is due to transitions between different energy
levels
24. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
GAS SPECTRA
Each element has characteristic emission and
absorption spectra, so scientists can use such
spectra to analyze the composition of matter.
25. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” ModicaCLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
ACTIVITY
• Play the game!
Site link:
http://spiff.rit.edu/classes/phys301/lectures/spec_lines/Atoms_Nav.swf
• Read “how to”
• Do the exercises
26. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
SPECRTOSCOPY
Spectra are used to provide information about the composition of a
substance or an object.
In particular, astronomers use emission and absorption spectra to
determine the composition of stars and interstellar matter.
We now know that the sun contains large amounts of hydrogen,
iron, and carbon, along with smaller amounts of other elements.
27. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” ModicaCLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
But…
• Bohr’s model only works for one electron
(hydrogen-like) atoms
• It can’t explain multi-electron atoms spectra
• It can’t explain multiplets of spectral lines
• Sub-levels
28. CLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” ModicaCLIL Physics/English Daniela Aprile Liceo Linguistico “G. Verga” Modica
Next lesson… over Bohr
• De Broglie's matter waves (wave–particle
duality)
• Schrödinger wave function
• Quantum numbers
• Heisenberg's Uncertainty Principle (1927)
• Probability wave
• Orbital, shell, sub-shell
• Electronic configuration
• Aufbau
