The Earth’s climate is dynamic and characterised by trends, aberrations and quasi-periodic oscillations varying over a broad range of time-scales [1], which are governed by external (extraterrestrial systems) and/or internal(ocean, atmosphere and land system). Trends are largely controlled by plate tectonics, and thus to change gradually on million year time scale. Aberrations occur when the certain thresholds are passed and are manifested in the geological record as the unusual rapid (less than a few thousands of years) or extreme change in climate. The quasi-periodic oscillations are mostly astronomically paced; they are driven by astronomical perturbations that affect the earth’s orbit around the sun and the orientation of earth’s rotation axis with respect to its orbital plane. These perturbations are described by the three main astronomical cycles: eccentricity, precession and obliquity, which together determine the spatial and seasonal pattern of insolation received by the earth [2], eventually resulting in climatic oscillations of ten to hundreds of thousands of year [3].Sun being the main source of energy for the earth system controls the climate of it. Variation in solar activity and cosmic ray intensity has direct influence over climatic features such as cloudiness, temperature and rainfall [4]. Volcanic eruptions also force all elements of the climatic systems up to a varying degree but producing long term climatic signals in the ocean. The cumulative volcanic cooling effect at present offsets about one third of anthropogenic warming [5].Other than these causes paleoclimatologists also relates the past climate changes with movement of solar system[6], interplanetary dusts and influence of asteroids[7].However the recent variability in climate what earth is experiencing is unlikely due to any of the individual above factors rather it is due to the compound effect of complex interactions of all the natural as well as anthropogenic forcings.
References:
1. J. C. Zachos, M. Pagani, L. Sloan, E. Thomas, K. Billups, Science 292 (2001) 686-693.
2. G. Kukla, Nature (London) 253, 600 (1975).
3. J. D. Hays, J. Imbrie, N. J. Shackleton, Science 194 (1876) 1121-1132.
4. N. Marsh, H. Swensmark, Space Sci. Rev. 94 (2000) 215-230.
5. T. L. Delworth, V. Ramaswamy, G. L. Stenchikov, Geophys. Res. Lett. 32 (2005) L24709.
6. K. Fuhrer, E. W. Wolf, S. J. Johnsen, J. Geophys. Res. 104(D24) (1999) 31043-31052
7. P. Hut, W. Alvarez, W. P. Elder, T. Hansen, E. G. Kauffman, G. Keller, E. M. Shoemaker & P. R. Weissman, Nature Vol. 329, 10 September, 1987
The Earth’s climate is dynamic and characterised by trends, aberrations and quasi-periodic oscillations varying over a broad range of time-scales [1], which are governed by external (extraterrestrial systems) and/or internal(ocean, atmosphere and land system). Trends are largely controlled by plate tectonics, and thus to change gradually on million year time scale. Aberrations occur when the certain thresholds are passed and are manifested in the geological record as the unusual rapid (less than a few thousands of years) or extreme change in climate. The quasi-periodic oscillations are mostly astronomically paced; they are driven by astronomical perturbations that affect the earth’s orbit around the sun and the orientation of earth’s rotation axis with respect to its orbital plane. These perturbations are described by the three main astronomical cycles: eccentricity, precession and obliquity, which together determine the spatial and seasonal pattern of insolation received by the earth [2], eventually resulting in climatic oscillations of ten to hundreds of thousands of year [3].Sun being the main source of energy for the earth system controls the climate of it. Variation in solar activity and cosmic ray intensity has direct influence over climatic features such as cloudiness, temperature and rainfall [4]. Volcanic eruptions also force all elements of the climatic systems up to a varying degree but producing long term climatic signals in the ocean. The cumulative volcanic cooling effect at present offsets about one third of anthropogenic warming [5].Other than these causes paleoclimatologists also relates the past climate changes with movement of solar system[6], interplanetary dusts and influence of asteroids[7].However the recent variability in climate what earth is experiencing is unlikely due to any of the individual above factors rather it is due to the compound effect of complex interactions of all the natural as well as anthropogenic forcings.
References:
1. J. C. Zachos, M. Pagani, L. Sloan, E. Thomas, K. Billups, Science 292 (2001) 686-693.
2. G. Kukla, Nature (London) 253, 600 (1975).
3. J. D. Hays, J. Imbrie, N. J. Shackleton, Science 194 (1876) 1121-1132.
4. N. Marsh, H. Swensmark, Space Sci. Rev. 94 (2000) 215-230.
5. T. L. Delworth, V. Ramaswamy, G. L. Stenchikov, Geophys. Res. Lett. 32 (2005) L24709.
6. K. Fuhrer, E. W. Wolf, S. J. Johnsen, J. Geophys. Res. 104(D24) (1999) 31043-31052
7. P. Hut, W. Alvarez, W. P. Elder, T. Hansen, E. G. Kauffman, G. Keller, E. M. Shoemaker & P. R. Weissman, Nature Vol. 329, 10 September, 1987
"Climate Change 2007: The Physical Science Basis", assesses the current
scientific knowledge of the natural and human drivers of climate change,
observed changes in climate, the ability of science to attribute changes
to different causes, and projections for future climate change.
The report was produced by some 600 authors from 40 countries. Over 620
expert reviewers and a large number of government reviewers also
participated. Representatives from 113 governments reviewed and revised
the Summary line-by-line during the course of this week before adopting
it and accepting the underlying report.
“Climate Change
2007: The Physical Science Basis”, assesses the current scientific knowledge of
the natural and human drivers of climate change, observed changes in climate,
the ability of science to attribute changes to different causes, and projections
for future climate change.
The report was
produced by some 600 authors from 40 countries. Over 620 expert reviewers and a
large number of government reviewers also participated. Representatives from 113
governments reviewed and revised the Summary line-by-line during the course of
this week before adopting it and accepting the underlying
report.
Climate Change Basics: Issues and Impacts for BoatingNASBLA
State Climatologist David Zierden presented Climate Change Basics: Issues and Impacts for Boating to the National Association of State Boating Law Administrators on September 9, 2008
"Climate Change 2007: The Physical Science Basis", assesses the current
scientific knowledge of the natural and human drivers of climate change,
observed changes in climate, the ability of science to attribute changes
to different causes, and projections for future climate change.
The report was produced by some 600 authors from 40 countries. Over 620
expert reviewers and a large number of government reviewers also
participated. Representatives from 113 governments reviewed and revised
the Summary line-by-line during the course of this week before adopting
it and accepting the underlying report.
“Climate Change
2007: The Physical Science Basis”, assesses the current scientific knowledge of
the natural and human drivers of climate change, observed changes in climate,
the ability of science to attribute changes to different causes, and projections
for future climate change.
The report was
produced by some 600 authors from 40 countries. Over 620 expert reviewers and a
large number of government reviewers also participated. Representatives from 113
governments reviewed and revised the Summary line-by-line during the course of
this week before adopting it and accepting the underlying
report.
Climate Change Basics: Issues and Impacts for BoatingNASBLA
State Climatologist David Zierden presented Climate Change Basics: Issues and Impacts for Boating to the National Association of State Boating Law Administrators on September 9, 2008
Khảo sát thành phần hóa học cây phèn đen phyllanthus reticulatus poir. họ thầ...NOT
Giá 10k/lượt download Liên hệ page để mua: https://www.facebook.com/garmentspace Xin chào, Nếu bạn cần mua tài liệu xin vui lòng liên hệ facebook: https://www.facebook.com/garmentspace Tại sao tài liệu lại có phí ??? Tài liệu một phần do mình bỏ thời gian sưu tầm trên Internet, một số do mình bỏ tiền mua từ các website bán tài liệu, với chi phí chỉ 10k cho lượt download tài liệu bất kỳ bạn sẽ không tìm ra nơi nào cung cấp tài liệu với mức phí như thế, xin hãy ủng hộ Garment Space nhé, đừng ném đá. Xin cảm ơn rất nhiều
Global warming and climate change are terms for the observed century-scale rise in the average temperature of the Earth's climate system and its related effects.
Multiple lines of scientific evidence show that the climate system is warming.
Temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures. Ocean temperatures increase more slowly than land temperatures because of the larger effective heat capacity of the oceans and because the ocean loses more heat by evaporation
Vivid description about climate change
A NASA database based presentation.
Geoengineering, solar , Mitigation and Adaption
a social cause , vital signs of planet
brief intoduction
www.climate.nasa.gov
Social climate change & water crisisIan Mohammed
this z a ppt on climate change and water crisis
well, I would actually say that a few slides in da climate change r frm other ppt's bt most dem were searched by myself.
in da water crisis also I hv done da same....
for more info;s I hv also made a page of IMPORTANT references..
thank u
hope u'd lyk it
comment below
a change in global or regional climate patterns, in particular a change apparent from the mid to late 20th century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels.
a change in global or regional climate patterns, in particular a change apparent from the mid to late 20th century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels.
The largest association of meteorologists and climate scientists issued a fresh statement on the scientific evidence for human-driven climate change and possible impacts. This is an update from the 2007 statement that can be found here: http://www.ametsoc.org/policy/2007climatechange.html
More on climate change on Dot Earth:
http://j.mp/dotBasic http://j.mp/dotBasics
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...!
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.
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.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
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.
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.
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. Global warming and climate change are terms for the
observed century-scale rise in the average temperature of
the Earth's climate system and its related effects.
Multiple lines of scientific evidence show that the climate
system is warming.
Temperature changes vary over the globe. Since 1979,
land temperatures have increased about twice as fast as
ocean temperatures. Ocean temperatures increase more
slowly than land temperatures because of the larger
effective heat capacity of the oceans and because the ocean
loses more heat by evaporation.
3. The northern hemisphere is
also naturally warmer than
the southern
hemisphere mainly because
of meridional heat transport
in the oceans.
Hemisphere this does not
contribute to the difference
in warming because the
major greenhouse gases
persist long enough to mix
between hemispheres.
4. Initial causes of temperature changes
The climate system can
respond to changes
in external forcings.
External forcings can
"push" the climate in the
direction of warming or
cooling. Examples of
external forcings include
changes in atmospheric
composition (e.g.,
increased concentrations
of greenhouse gases, solar
luminosity, volcanic
eruptions).
5. Anthropogenic forcing
has likely contributed
to some of the
observed changes,
including sea level
rise, changes in
climate extremes as
the number of warm
and cold
days, declines in
Arctic see ice extent,
glacier retreat and
greening in Sahara.
Detection “is the
process of
demonstrating that
climate has changed
in some
defined statistical
sense, without
providing a reason for
that change”.
Detection does not
imply attribution of
the detected change
to a particular cause.
6. Extreme weather
Changes in regional climate are expected to include
greater warming over land, with most warming at high
northern latitudes, and least warming over
the Southern Ocean and parts of the North Atlantic
Ocean.
Future changes in precipitation are expected to follow
existing trends, with reduced precipitation
over subtropical land areas, and increased
precipitation at subpolar latitudes and
some equatorial regions.
7. Long-term effects
• On the timescale of centuries to millennia, the
magnitude of global warming will be determined
primarily by anthropogenic CO2 emissions. This is
due to carbon dioxide's very long lifetime in the
atmosphere.
• Stabilizing global average temperature would
require reductions in anthropogenic CO2 emissions.
Reductions in emissions of non-CO2 anthropogenic
greenhouse gases (e.g., methane and nitrous oxide)
would also be necessary.