1,451 research outputs found
Effects of Two Strains of Tobacco Mosaic Virus on Photosynthetic Characteristics and Nitrogen Partitioning in Leaves of Nicotiana tabacum cv Xanthi during Photoacclimation under Two Nitrogen Nutrition Regimes
Paper Session II-C - Legal Challenges in Realizing Interstellar Initiatives
Exploration of our solar system and beyond has barely begun. The challenges of space are limitless, and each addition to our ability to operate there opens new legal concerns between ourselves and our international partners. We are in fact living at the very beginning of time. Our descendants of far-off ages will use the legal framework we put in place to reach unimaginable opportunities. In the past our forefathers never envisioned the United States Constitution to be such a strong source of power for the government. Consequently We the people of the United States have the Bill of Rights. Will the legal framework we establish provide the guidance to extend beyond the solar system and journey to other stars?
In taking the logical steps in space to realize Space Exploration Initiative and beyond we must consider the legalities associated with birth, life, and death. Thus, the issue of birth on another planet is discussed. Would a lunar or Mars born space traveler obtain citizenship through the United Nations registry? To what earth bound land would this traveler be sovereign? The time of the birth, the day, and even the calendar year must be described in such a manner that when man does go beyond the solar system to other stars the legal framework established goes as well. Will the framework provide for genetic engineering to be realized in other worlds and not be suppressed by social and political earthbound ways
Photorespiration: metabolic pathways and their role in stress protection
Photorespiration results from the oxygenase reaction catalysed by ribulose-1,5-bisphosphate carboxylase/
oxygenase. In this reaction glycollate-2-phosphate is produced and subsequently metabolized in the
photorespiratory pathway to form the Calvin cycle intermediate glycerate-3-phosphate. During this metabolic
process, CO2 and NH3 are produced and ATP and reducing equivalents are consumed, thus
making photorespiration a wasteful process. However, precisely because of this ine€ciency, photorespiration
could serve as an energy sink preventing the overreduction of the photosynthetic electron transport
chain and photoinhibition, especially under stress conditions that lead to reduced rates of photosynthetic
CO2 assimilation. Furthermore, photorespiration provides metabolites for other metabolic processes, e.g.
glycine for the synthesis of glutathione, which is also involved in stress protection. In this review, we
describe the use of photorespiratory mutants to study the control and regulation of photorespiratory pathways.
In addition, we discuss the possible role of photorespiration under stress conditions, such as
drought, high salt concentrations and high light intensities encountered by alpine plants
Aboriginal Rules: The Black History of Australian Football
This paper is interested in the significance of Australian football to the Aboriginal and Torres Strait Islander people of Australia. In particular, this paper is interested in the cultural power of football and how it has foregrounded the struggle and highlighted the contribution that Indigenous people have made to the national football code of Australia. This paper also discusses key moments in Indigenous football history in Australia. It questions further that a greater understanding of this contribution needs to be more fully explored from a national perspective in order to appreciate Indigenous peoples' contribution to the sport not just in elite competitions but also at a community and grass roots level
Do daily and seasonal trends in leaf solar induced fluorescence reflect changes in photosynthesis, growth or light exposure?
Solar induced chlorophyll fluorescence (SIF) emissions of photosynthetically active plants retrieved from space-borne observations have been used to improve models of global primary productivity. However, the relationship between SIF and photosynthesis in diurnal and seasonal cycles is still not fully understood, especially at large spatial scales, where direct measurements of photosynthesis are unfeasible. Motivated by up-scaling potential, this study examined the diurnal and seasonal relationship between SIF and photosynthetic parameters measured at the level of individual leaves. We monitored SIF in two plant species, avocado (Persea Americana) and orange jasmine (Murraya paniculatta), throughout 18 diurnal cycles during the Southern Hemisphere spring, summer and autumn, and compared them with simultaneous measurements of photosynthetic yields, and leaf and global irradiances. Results showed that at seasonal time scales SIF is principally correlated with changes in leaf irradiance, electron transport rates (ETR) and constitutive heat dissipation (YNO; p \u3c 0.001). Multiple regression models of correlations between photosynthetic parameters and SIF at diurnal time scales identified leaf irradiance as the principle predictor of SIF (p \u3c 0.001). Previous studies have identified correlations between photosynthetic yields, ETR and SIF at larger spatial scales, where heterogeneous canopy architecture and landscape spatial patterns influence the spectral and photosynthetic measurements. Although this study found a significant correlation between leaf-measured YNO and SIF, future dedicated up-scaling experiments are required to elucidate if these observations are also found at larger spatial scales
Complex effects of helper relatedness on female extrapair reproduction in a cooperative breeder
In cooperatively breeding species, the presence of male helpers in a group often reduces the breeding femaleâs fidelity to her social partner, possibly because there is more than one potential sire in the group. Using a long-term study of cooperatively breeding superb fairy-wrens (Malurus cyaneus) and records of paternity in 1936 broods, we show that the effect of helpers on rates of extrapair paternity varied according to the helpersâ relatedness to the breeding female. The presence of unrelated male helpers in a group increased average rates of extrapair paternity, from 57% for groups with no unrelated helpers, to 74% with one unrelated helper, to 86% with 2+ unrelated helpers. However, this increase was due in equal part to helpers within the group and males in other groups achieving increased paternity. In contrast, helpers who were sons of the breeding female did not gain paternity, nor did they affect the level of extra-group paternity (which occurred at rates of 60%, 58%, 61% in the presence of 0, 1, 2+ helper sons, respectively). There was no evidence of effects of helpersâ relatedness to the female on nest productivity or nestling performance. Because the presence of helpers per se did not elevate extrapair reproduction rates, our results undermine the âconstrained female hypothesisâ explanation for an increase in extrapair paternity with helper number in cooperative breeders. However, they indicate that dominant males are disadvantaged by breeding in âcooperativeâ groups. The reasons why the presence of unrelated helpers, but not of helper-sons, results in higher rates of extra-group reproduction are not clear.G.K.H. was supported by the U.K. Natural Environment Research Council (Grant NE/L002558/1) through the University of Edinburghâs E3 Doctoral Training Partnership. The long-term research has been facilitated b
Susceptibility of Tobacco Leaves to Photoinhibition following Infection with Two Strains of Tobacco Mosaic Virus under Different Light and Nitrogen Nutrition Regimes
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