Spatio-temporal resolution of primary processes of photosynthesis

2015 ◽  
Vol 177 ◽  
pp. 547-562 ◽  
Author(s):  
Wolfgang Junge
Keyword(s):  
Energy Demand ◽  
Solid State Reactions ◽  
Oxygenic Photosynthesis ◽  
Excitable Systems ◽  
Order Of Magnitude ◽  
Molecular Machinery ◽  
Laser Sources ◽  
New Methodologies ◽  
Spatio Temporal ◽  
Life On Earth

Technical progress in laser-sources and detectors has allowed the temporal and spatial resolution of chemical reactions down to femtoseconds and Å-units. In photon-excitable systems the key to chemical kinetics, trajectories across the vibrational saddle landscape, are experimentally accessible. Simple and thus well-defined chemical compounds are preferred objects for calibrating new methodologies and carving out paradigms of chemical dynamics, as shown in several contributions to thisFaraday Discussion. Aerobic life on earth is powered by solar energy, which is captured by microorganisms and plants. Oxygenic photosynthesis relies on a three billion year old molecular machinery which is as well defined as simpler chemical constructs. It has been analysed to a very high precision. The transfer of excitation between pigments in antennae proteins, of electrons between redox-cofactors in reaction centres, and the oxidation of water by a Mn4Ca-cluster are solid state reactions. ATP, the general energy currency of the cell, is synthesized by a most agile, rotary molecular machine. While the efficiency of photosynthesis competes well with photovoltaics at the time scale of nanoseconds, it is lower by an order of magnitude for crops and again lower for bio-fuels. The enormous energy demand of mankind calls for engineered (bio-mimetic or bio-inspired) solar-electric and solar-fuel devices.

scholarly journals Small-scale spatio-temporal characteristics of accumulation rates in western Dronning Maud Land, Antarctica

2008 ◽  
Vol 54 (185) ◽  
pp. 315-323 ◽  
Author(s):  
Helgard Anschütz ◽  
Daniel Steinhage ◽  
Olaf Eisen ◽  
Hans Oerter ◽  
Martin Horwath ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Temporal Variations ◽  
Spatial Variations ◽  
Small Scale ◽  
Accumulation Rates ◽  
Order Of Magnitude ◽  
Dronning Maud Land ◽  
Spatio Temporal ◽  
Ground Penetrating ◽  
Firn Core

AbstractSpatio-temporal variations of the recently determined accumulation rate are investigated using ground-penetrating radar (GPR) measurements and firn-core studies. The study area is located on Ritscherflya in western Dronning Maud Land, Antarctica, at an elevation range 1400–1560 m. Accumulation rates are derived from internal reflection horizons (IRHs), tracked with GPR, which are connected to a dated firn core. GPR-derived internal layer depths show small relief along a 22 km profile on an ice flowline. Average accumulation rates are about 190 kg m−2 a−1 (1980–2005) with spatial variability (1σ) of 5% along the GPR profile. The interannual variability obtained from four dated firn cores is one order of magnitude higher, showing 1σ standard deviations around 30%. Mean temporal variations of GPRderived accumulation rates are of the same magnitude or even higher than spatial variations. Temporal differences between 1980–90 and 1990–2005, obtained from two dated IRHs along the GPR profile, indicate temporally non-stationary processes, linked to spatial variations. Comparison with similarly obtained accumulation data from another coastal area in central Dronning Maud Land confirms this observation. Our results contribute to understanding spatio-temporal variations of the accumulation processes, necessary for the validation of satellite data (e.g. altimetry studies and gravity missions such as Gravity Recovery and Climate Experiment (GRACE)).

scholarly journals Insights into the evolution of oxygenic photosynthesis from a phylogenetically novel, low-light cyanobacterium

2018 ◽  
Author(s):  
Christen L. Grettenberger ◽  
Dawn Y. Sumner ◽  
Kate Wall ◽  
C. Titus Brown ◽  
Jonathan Eisen ◽  
...  
Keyword(s):  
Atmospheric Oxygen ◽  
Evolutionary Model ◽  
Reaction Centers ◽  
Oxygenic Photosynthesis ◽  
Oxygen Production ◽  
Crown Group ◽  
Low Light ◽  
Extrinsic Proteins ◽  
Structural Parts ◽  
Life On Earth

AbstractAtmospheric oxygen level rose dramatically around 2.4 billion years ago due to oxygenic photosynthesis by the Cyanobacteria. The oxidation of surface environments permanently changed the future of life on Earth, yet the evolutionary processes leading to oxygen production are poorly constrained. Partial records of these evolutionary steps are preserved in the genomes of organisms phylogenetically placed between non-photosynthetic Melainabacteria, crown-group Cyanobacteria, and Gloeobacter, representing the earliest-branching Cyanobacteria capable of oxygenic photosynthesis. Here, we describe nearly complete, metagenome assembled genomes of an uncultured organism phylogenetically placed between the Melainabacteria and crown-group Cyanobacteria, for which we propose the name Candidatus Aurora vandensis {au.rora Latin noun dawn and vand.ensis, originating from Vanda}.The metagenome assembled genome of A. vandensis contains homologs of most genes necessary for oxygenic photosynthesis including key reaction center proteins. Many extrinsic proteins associated with the photosystems in other species are, however, missing or poorly conserved. The assembled genome also lacks homologs of genes associated with the pigments phycocyanoerethrin, phycoeretherin and several structural parts of the phycobilisome. Based on the content of the genome, we propose an evolutionary model for increasing efficiency of oxygenic photosynthesis through the evolution of extrinsic proteins to stabilize photosystem II and I reaction centers and improve photon capture. This model suggests that the evolution of oxygenic photosynthesis may have significantly preceded oxidation of Earth’s atmosphere due to low net oxygen production by early Cyanobacteria.

scholarly journals Editorial

2019 ◽  
Vol 30 (5) ◽  
pp. 829-829
Author(s):  
R. Kuske ◽  
D. Yurchenko
Keyword(s):  
Stochastic Models ◽  
Stochastic Dynamics ◽  
Single Issue ◽  
Stochastic Effects ◽  
Multi Scale ◽  
Multiscale Dynamics ◽  
New Methodologies ◽  
Spatio Temporal ◽  
Multi Mode ◽  
Different Sources

The origin of this special issue took place at the 9th European Nonlinear Dynamics Conference (ENOC 2017) in Budapest, Hungary. Specifically, the mini-symposium on Random Dynamical Systems – Recent Advances and New Directions brought together novel perspectives on analyzing stochastic dynamics with applications including biology, structural dynamics, control, energy and mechanics. The expanded use of stochasticity in more realistic models exposes questions related to bifurcations, meta-stability, tipping and early warning signals, multiscale dynamics, and connections between chaos and stochastic dynamics. The observed phenomena in applications drive new methodologies and analyses, needed to understand the interplay between different sources of stochastic effects and nonlinearities, network structure, multi-mode and multi-scale behavior, non-smooth dynamics, energy transfer, and spatio-temporal phenomena. Of course, a single issue cannot hope to cover all of the new topics in stochastic analysis for applications. Nevertheless, we hope that the collection of applications and stochastic models presented in this issue illustrates some of the exciting advances and perspectives relevant for broad classes of stochastic models and demonstrates the need in advancing the theory of stochastic processes.

The fine details of evolution

2009 ◽  
Vol 37 (4) ◽  
pp. 723-726 ◽  
Author(s):  
Roman A. Laskowski ◽  
Janet M. Thornton ◽  
Michael J.E. Sternberg
Keyword(s):  
Three Dimensional ◽  
Protein Sequences ◽  
Theory Of Evolution ◽  
Death Studies ◽  
Living Things ◽  
Wide Range ◽  
Molecular Machinery ◽  
Conference Centre ◽  
Life On Earth ◽  
Oral Presentations

Charles Darwin's theory of evolution was based on studies of biology at the species level. In the time since his death, studies at the molecular level have confirmed his ideas about the kinship of all life on Earth and have provided a wealth of detail about the evolutionary relationships between different species and a deeper understanding of the finer workings of natural selection. We now have a wealth of data, including the genome sequences of a wide range of organisms, an even larger number of protein sequences, a significant knowledge of the three-dimensional structures of proteins, DNA and other biological molecules, and a huge body of information about the operation of these molecules as systems in the molecular machinery of all living things. This issue of Biochemical Society Transactions contains papers from oral presentations given at a Biochemical Society Focused Meeting to commemorate the 200th Anniversary of Charles Darwin's birth, held on 26–27 January 2009 at the Wellcome Trust Conference Centre, Cambridge. The talks reported on some of the insights into evolution which have been obtained from the study of protein sequences, structures and systems.

scholarly journals Consumers' Response to State Energy Efficient Appliance Rebate Programs

2017 ◽  
Vol 9 (4) ◽  
pp. 227-255 ◽  
Author(s):  
Sébastien Houde ◽  
Joseph E. Aldy
Keyword(s):  
Energy Efficiency ◽  
Energy Efficient ◽  
Energy Demand ◽  
State Energy ◽  
Government Expenditure ◽  
Order Of Magnitude ◽  
Term Energy ◽  
The Impact

Through an evaluation of the 2009 Recovery Act's State Energy Efficient Appliance Rebate Program, this paper examines consumers' response to energy efficiency rebates. The analysis shows that 70 percent of consumers claiming a rebate were inframarginal and an additional 15 percent–20 percent of consumers simply delayed their purchases by a few weeks. Consumers responded to rebates by upgrading to higher quality, but less energy-efficient models. Overall the impact of the program on long-term energy demand is likely to be small. Measures of government expenditure per unit of energy saved are an order of magnitude higher than estimates for other energy efficiency programs. (JEL D12, H31, H71, Q48)

scholarly journals Spatio-Temporal Analysis of Heating and Cooling Degree-Days Over Iran

2021 ◽  
Author(s):  
Amin Sadeqi ◽  
Hossein Tabari ◽  
Yagob Dinpashoh
Keyword(s):  
Time Series ◽  
Energy Demand ◽  
Temporal Trends ◽  
Temporal Analysis ◽  
Degree Days ◽  
Heating And Cooling ◽  
Cooling Degree Days ◽  
Spatio Temporal ◽  
Heating Degree Days ◽  
Cooling Energy Demand

Abstract Climate change affects the energy demand in different sectors of the society. To investigate this possible impact, in this research, temporal trends and change points in heating degree-days (HDD), cooling degree-days (CDD), and their simultaneous combination (HDD+CDD) were analysed for a 60-year period (1960-2019) in Iran. The results show that less than 20% of the study stations had significant trends (either upward or downward) in HDD time series, while more than 80% of the stations had significant increasing trends in CDD and HDD+CDD time series. Abrupt changes in HDD time series mostly occurred in the early 1980s, but those in CDD time series were mostly observed in the 1990s. The cooling energy demand in Iran has dramatically increased as CDD values have raised up from 690 ºC-days to 1010 ºC-days in the last 60 years. HDD, however, almost remained constant in the same period. The results suggest that if global warming continues with the current pace, cooling energy demand in the residential sector will considerably increase in the future, calling for a change in residential energy consumption policies.

Closing remarks: astronomical

1990 ◽  
Vol 330 (1615) ◽  
pp. 683-684 ◽  
Keyword(s):  
Solar Activity ◽  
Decisive Role ◽  
The Sun ◽  
Physical Conditions ◽  
Dust Clouds ◽  
The Galaxy ◽  
Order Of Magnitude ◽  
Earth’S Climate ◽  
Life On Earth ◽  
Physical And Chemical

Over the past two days, we have covered many facets of the basic interactions between the solar activity and the Earth’s climate. As an astronomer, I should perhaps first comment on the fact that solar activity is not the only astronomical or astrophysical phenomenon to influence physical conditions in the biosphere. Over a very long timescale of thousands of millions of years the evolution of the Sun from a pre-main-sequence star to a star of G type has not only fundamentally controlled the physical and chemical processes in the formation of the planets but has controlled their surface physical characteristics. Over timescales an order of magnitude less, the location of the Solar System in the Galaxy may have influenced life on Earth. For example it has been noted that when the Sun crossed the spiral arms of the Galaxy and their dense dust clouds, some catastrophies might have resulted; the disappearance of the dinosaurs could be accounted for by such phenomena, as was once suggested by Sir William McCrea, F.R.S.; but nearby supernovae, grazing comets, and on large meteorites might very well have played a decisive role in the evolution of species and of our Earth. On a smaller timescale, a million years, the variation in solar energy falling on the Earth, due to secular changes in the terrestrial orbit parameters (Milankovitch-Berger theories), would have caused climatic changes and have been shown to account for the successive ice ages of the Quaternary. While bearing this in mind the role of solar activity on the timescale of recent millennia, but also on shorter timescales, is of obvious importance to society and, as we have seen in this meeting, is only now being properly investigated.

scholarly journals Targeted and Highly Multiplexed Detection of Microorganisms by Employing an Ensemble of Molecular Probes

2014 ◽  
Vol 80 (14) ◽  
pp. 4153-4161 ◽  
Author(s):  
Weihong Xu ◽  
Sujatha Krishnakumar ◽  
Molly Miranda ◽  
Michael A. Jensen ◽  
Marilyn Fukushima ◽  
...  
Keyword(s):  
Abundant Species ◽  
Laboratory Culture ◽  
Molecular Probes ◽  
Molecular Probe ◽  
Clinical Samples ◽  
Culture Independent ◽  
Order Of Magnitude ◽  
Life On Earth ◽  
Probe Set ◽  
Selection Of

ABSTRACTThe vast majority of microscopic life on earth consists of microbes that do not grow in laboratory culture. To profile the microbial diversity in environmental and clinical samples, we have devised and employed molecular probe technology, which detects and identifies bacteria that do and do not grow in culture. The only requirement is a short sequence of contiguous bases (currently 60 bases) unique to the genome of the organism of interest. The procedure is relatively fast, inexpensive, customizable, robust, and culture independent and uses commercially available reagents and instruments. In this communication, we report improving the specificity of the molecular probes substantially and increasing the complexity of the molecular probe set by over an order of magnitude (>1,200 probes) and introduce a new final readout method based upon Illumina sequencing. In addition, we employed molecular probes to identify the bacteria from vaginal swabs and demonstrate how a deliberate selection of molecular probes can identify less abundant bacteria even in the presence of much more abundant species.

Understanding Energy Demand Behaviors through Spatio-temporal Smart Meter Data Analysis

Energy ◽  
2021 ◽  
pp. 120493
Author(s):  
Zhibin Niu ◽  
Junqi Wu ◽  
Xiufeng Liu ◽  
Lizhen Huang ◽  
Per Sieverts Nielsen
Keyword(s):  
Data Analysis ◽  
Energy Demand ◽  
Smart Meter ◽  
Spatio Temporal
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