Emerging research in plant photosynthesis

2020 ◽  
Vol 4 (2) ◽  
pp. 137-150 ◽  
Author(s):  
Thomas D. Sharkey
Keyword(s):  
Green Light ◽  
Basic Research ◽  
Light Energy ◽  
Good News ◽  
Regulatory Mechanisms ◽  
Large Area ◽  
Protective Mechanisms ◽  
Light Levels ◽  
Plant Photosynthesis ◽  
To Come

Photosynthesis involves capturing light energy and, most often, converting it to chemical energy stored as reduced carbon. It is the source of food, fuel, and fiber and there is a resurgent interest in basic research on photosynthesis. Plants make excellent use of visible light energy; leaves are ideally suited to optimize light use by having a large area per amount of material invested and also having leaf angles to optimize light utilization. It is thought that plants do not use green light but in fact they use green light better than blue light under some conditions. Leaves also have mechanisms to protect against excess light and how these work in a stochastic light environment is currently a very active area of current research. The speed at which photosynthesis can begin when leaves are first exposed to light and the speed of induction of protective mechanisms, as well as the speed at which protective mechanisms dissipate when light levels decline, have recently been explored. Research is also focused on reducing wasteful processes such as photorespiration, when oxygen instead of carbon dioxide is used. Some success has been reported in altering the path of carbon in photorespiration but on closer inspection there appears to be unforeseen effects contributing to the good news. The stoichiometry of interaction of light reactions with carbon metabolism is rigid and the time constants vary tremendously presenting large challenges to regulatory mechanisms. Regulatory mechanisms will be the topic of photosynthesis research for some time to come.

DySlExIa: Good News, More to Come!

1985 ◽  
Vol 30 (4) ◽  
pp. 305-306
Author(s):  
Dennis F. Fisher
Keyword(s):  
Good News ◽  
To Come

scholarly journals A 3 W High-Voltage Single-Chip Green Light-Emitting Diode with Multiple-Cells Network

2015 ◽  
Vol 2015 ◽  
pp. 1-4 ◽  
Author(s):  
W. Wang ◽  
Y. Cai ◽  
Y. B. Zhang ◽  
H. J. Huang ◽  
W. Huang ◽  
...  
Keyword(s):  
High Voltage ◽  
Light Emitting Diode ◽  
Light Output ◽  
Green Light ◽  
Current Crowding ◽  
Single Chip ◽  
Light Output Power ◽  
Large Area ◽  
Light Emitting ◽  
Multiple Cells

A parallel and series network structure was introduced into the design of the high-voltage single-chip (HV-SC) light-emitting diode to inhibit the effect of current crowding and to improve the yield. Using such a design, a6.6×5 mm2large area LED chip of 24 parallel stages was demonstrated with 3 W light output power (LOP) at the current of 500 mA. The forward voltage was measured to be 83 V with the same current injection, corresponding to 3.5 V for a single stage. The LED chip’s average thermal resistance was identified to be 0.28 K/W by using infrared thermography analysis.

scholarly journals Taking responsibility for reconciliation: a Christian response to the legacy and challenges of the South African Truth and Reconciliation Commission (TRC)

2009 ◽  
Vol 43 (2) ◽  
Author(s):  
S. Barry
Keyword(s):  
South African ◽  
Healing Process ◽  
Truth And Reconciliation Commission ◽  
Good News ◽  
Reconciliation Commission ◽  
South Africans ◽  
Truth And Reconciliation ◽  
Christian Churches ◽  
To Come ◽  
Desmond Tutu

At the conclusion of the TRC, Desmond Tutu stated that the Commission’s task was to promote, not to achieve, reconci- liation. Reconciliation, he maintained, is the responsibility of all South Africans, and expressed the hope that the Christian churches would be in the forefront of this healing process.  This article explores how the Christian church can be in the forefront of binding up the wounds, facilitating the healing pro- cess, and living as a people and a sign of hope. The answers it seeks to offer fall under three interrelated themes, namely the church’s:  • spirituality of reconciliation; • ministry and mission of reconciliation; and • resources for its ministry and mission of reconciliation. Cultivating a spirituality of reconciliation would mean making reconciliation a lifestyle, rather than a series of strategies, pro- grammes or initiatives, yet remaining concrete, practical, mea- surable and accountable.   The church’s mission is primarily to proclaim the good news of God’s Kingdom that is already here, but not yet fully here and therefore still to come. This proclamation is the message of reconciliation between God, others and the self, and anticipates the unity of all creation in Jesus Christ.   The resources given to the church to fulfil this apostolic ministry include prophecy, evangelism, pastoral care and teaching, as well as its liturgical and sacramental life, its ministry of pre- sence, its people and its commitment to social justice.

Study on the planarization behaviour of copper CMP utilizing a dense pattern and a global step

2005 ◽  
Vol 867 ◽  
Author(s):  
Tilo Bormann ◽  
Johann W. Bartha
Keyword(s):  
Removal Rate ◽  
Specific Pattern ◽  
Constant Density ◽  
Large Area ◽  
Before And After ◽  
Contour Evolution ◽  
Copper Cmp ◽  
To Come ◽  
Dense Pattern

AbstractThe major aim of CMP is not the removal of excess material but the planarization of the surface. Therefore the determination of the planarization length appears to be more important than the removal rate itself. It has been shown, that the planarization length is not a constant process parameter, but is related to the removal respectively to the polish time in a square root behaviour. Founded on models proposed by Boning, Ouma, et. al. we applied a sequential polish on a single quasi infinite step. The resulting profile could be simulated by a sequential convolution of the surface contour with a Gaussian transfer function.To come closer to the situation on a chip pattern we investigated the planarization behaviour on a specific pattern of the MIT854AZ copper CMP test chip, where a large area of unpatterned surface touches a pattern with a specific constant density.The 200 mm wafer samples consisted of RIE structured oxide films covered with 850 nm ECD copper. The polish was performed on a standard semiconductor manufacturing tool, using a commercial consumables set. The surface profiles were determined by a high resolution profiler within the polishing sequence. The densely patterned areas are removed within a certain polishing time while the transition point between the unpatterned and patterned area appears as a global step. The deposited copper thickness is sufficient to study the contour evolution in both phases, before and after removal of the dense pattern. The paper presents the experimental results on the contour evolution for the patterned fields as well as the global step.

EBSP: A powerful tool in studying recrystallization of metals

1994 ◽  
Vol 52 ◽  
pp. 610-611
Author(s):  
T. Furu ◽  
O. Lohne ◽  
Ø. Sødahl ◽  
E. Nes
Keyword(s):  
Texture Evolution ◽  
Basic Research ◽  
Recrystallization Process ◽  
Large Area ◽  
X Ray ◽  
Local Texture ◽  
Subgrain Growth ◽  
Short Processing Time ◽  
Back Scattering ◽  
Established Technique

The Electron Back Scattering Pattern Technique (EBSP), for measurements of crystal orientations is now a well established technique for microtexlure detennination. The application of the technique to material problems has increased quite substantially the last years, both in basic research and in more industry related problems. When studying the recrystallization process in detail a relatively large area of a specimen has to be investigated to obtain good statistical results. With a resolution of the order of 0.5-1 μm and a short processing time the EBSPtechnique has shown to be advantageous compared to TEM on one side and X-ray and neutron diffraction on the other. By the EBSP-technique we are able to follow the local texture evolution during transformation and are at the same time able to analyse changes in the untransfonncd matrix (i.e. subgrain growth etc.).It is well accepted that the formation of recrystallization nuclei is a highly heterogeneous process.

Material-based high-impedance surfaces for infrared photonic technologies

2022 ◽  
Vol 1 ◽  
pp. 1-4
Author(s):  
Iñigo Liberal ◽  
◽  
José Manuel Pérez-Escudero ◽  
Keyword(s):  
Basic Research ◽  
Large Area ◽  
Magnetic Conductor ◽  
Doped Semiconductors ◽  
Impedance Boundary ◽  
High Impedance ◽  
Radar Systems ◽  
Thermal Emitters ◽  
Push Forward ◽  
Infrared Frequencies

Metamaterial high-impedance surfaces (HISs) are characterized by a boundary condition close to that of aperfect magnetic conductor (PMC). This property has enabled a variety of antenna systems such as low-profileantennas, electromagnetic absorbers and anti-radar systems. Here, we push forward the concept of material-basedhigh-impedance surfaces (MatHISs), where a high-impedance boundary is directly obtained from the materialproperties of doped semiconductors and polar dielectrics at infrared frequencies. Technological advantages ofMatHISs such as fabrication simplicity, large-area deployment and integrability into conformal devices suggestmultiple applications for infrared photonic technologies, including dynamical thermal emitters, optoelectronic devicesand basic research on atomically-thin materials.

Shade lichens are characterized by rapid relaxation of non-photochemical quenching on transition to darkness

2021 ◽  
Vol 53 (5) ◽  
pp. 409-414
Author(s):  
Richard P. Beckett ◽  
Farida V. Minibayeva ◽  
Kwanele W. G. Mkhize
Keyword(s):  
Chlorophyll Fluorescence ◽  
Quantum Yield ◽  
Light Energy ◽  
Photochemical Quenching ◽  
Photosynthetic Organisms ◽  
Light Levels ◽  
Lower Light ◽  
Optimal Productivity ◽  
Sun And Shade ◽  
Non Photochemical Quenching

AbstractNon-photochemical quenching (NPQ) plays an important role in protecting photosynthetic organisms from photoinhibition by dissipating excess light energy as heat. However, excess NPQ can greatly reduce the quantum yield of photosynthesis at lower light levels. Recently, there has been considerable interest in understanding how plants balance NPQ to ensure optimal productivity in environments in which light levels are rapidly changing. In the present study, chlorophyll fluorescence was used to study the induction and relaxation of non-photochemical quenching (NPQ) in the dark and the induction of photosynthesis in ten species of lichens, five sampled from exposed and five sampled from shaded habitats. Here we show that the main difference between sun and shade lichens is the rate at which NPQ relaxes in the dark, rather than the speed that photosynthesis starts upon illumination. During the first two minutes in the dark, NPQ values in the five sun species declined only by an average of 2%, while by contrast, in shade species the average decline was 40%. For lichens growing in microhabitats where light levels are rapidly changing, rapid relaxation of NPQ may enable their photobionts to use the available light most efficiently.

scholarly journals The year of jubilee: a hermeneutic for social and moral transformation in South Africa

2011 ◽  
Vol 45 (4) ◽  
Author(s):  
S. Barry
Keyword(s):  
South Africa ◽  
Old Testament ◽  
Holy Spirit ◽  
Good News ◽  
Book Of Revelation ◽  
Moral Transformation ◽  
Ecological Responsibility ◽  
The Holy Spirit ◽  
To Come ◽  
Justice Restoration

This article aims to show that the Old Testament concept of the year of jubilee is neither an anachronistic, nor a peripheral de- tail of Scripture. It is an integral part of it and indeed one her- meneutical tool for interpreting and applying it to social and mo- ral transformation in South Africa.  Israel, liberated from slavery and returning to God, became a paradigm for the liberated slave to return to his inheritance in the year of jubilee celebrated every 50th year. Its underlying concerns are: justice, freedom, human dignity and rights.  Jesus clearly understood his mission in terms of the proclama- tion of “the year of the Lord’s favour” (Luke 4:14-21), and de- monstrated this by preaching good news to the poor, freeing the prisoners, restoring sight to the blind, and releasing the op- pressed. He linked the mission of his followers with his own and with the promise and gift of the Holy Spirit. Pentecost, seen as fulfilment and announcement of God’s promise, demonstrates that the kingdom of God is already here and still to come.   The Book of Revelation gathers together this scriptural theme and presents the jubilee as good news for now and the future. Indeed, God’s future is presented as the ultimate jubilee. Although these institutions cannot be imposed on a secular democracy, there are implications here for holistic evangelism and mission as well as for social and moral transformation in South Africa.   These implications, it is argued, should include a reference to the ‘missio Dei’ as Jesus expressed it: holistic evangelism; a commitment to the values and practices of restorative justice; restoration, healing and hope; economic justice and land re- form; ecological responsibility; and moral restoration.

Response of carp (Cyprinus carpio) horizontal cells to heterochromatic flicker photometry

2006 ◽  
Vol 23 (3-4) ◽  
pp. 437-440 ◽  
Author(s):  
MARLISON JOSÉ L. DE AGUIAR ◽  
DORA FIX VENTURA ◽  
MANOEL DA SILVA FILHO ◽  
JOHN MANUEL DE SOUZA ◽  
ROGÉRIO MACIEL ◽  
...  
Keyword(s):  
Horizontal Cell ◽  
Red Light ◽  
Green Light ◽  
Physiological Solution ◽  
Horizontal Cells ◽  
Xenon Lamp ◽  
Constant Amplitude ◽  
Light Levels ◽  
Electrophysiological Recordings ◽  
Heterochromatic Flicker Photometry

The objective of the present work was to determine the interaction of cone inputs in the response of horizontal cells using heterochromatic flicker photometry (HFP). Intracellular electrophysiological recordings were made in horizontal cells of isolated retinae of carp maintained in physiological solution, with the receptor side up. Sharp glass microelectrodes filled with 3 M KCl solution with resistances between 100 and 120 MΩ were used. Stimuli comprised six cycles of two 6-Hz sinusoidal light waves in counterphase adjusted for the same number of quanta: a green light (550 nm) from a monochromator with a Xenon lamp and an LED red light (628 nm). The stimulation program consisted of 10 steps with the 550-nm wave at constant amplitude, while the 628-nm wave varied in increments of 10% up to 100%, followed by another 10 steps with the 628-nm wave at constant amplitude while the 550-nm wave varied in increments of 10% up to 100%. We recorded responses from four different horizontal cell classes: H1 (monophasic, broadband, n = 37), H2 (biphasic, red-green color-opponent, n = 13), and H3 (biphasic, blue-yellow color-opponent, n = 2) cone horizontal cells; and RH (monophasic, broadband, n = 3) rod horizontal cells. H1 and RH horizontal cells showed a similar cancellation point at a heterochromatic mixture consistent with mixed inputs from 630- and 550-nm cones. No cancellation point was found for the H2 cell class. Fish H1 cells add cone inputs and signal “luminance” in light levels appropriate for cone stimulation. The same occurs with RH cells, which also signal “luminance,” but in light levels appropriate for rod work. For both cell classes there is an HFP cancellation point occurring at a combination of 628-nm and 550-nm lights in opposing phase that leads to the cancellation of the cell's response. No cancellation was found for H2 and H3 cells, which are the chromatically opponent horizontal cells in lower vertebrates.

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