The Impact of Atmospheric Composition on the Evolutionary Development of Stomatal Control and Biochemistry of Photosynthesis over the Past 450 Ma

Author(s):  
Matthew Haworth ◽  
Giovanni Marino ◽  
Mauro Centritto
2019 ◽  
Vol 7 (8) ◽  
pp. 260
Author(s):  
Florent Domine

Since 1999, atmospheric and snow chemists have shown that snow is a very active photochemical reactor that releases reactive gaseous species to the atmosphere including nitrogen oxides, hydrocarbons, aldehydes, halocarbons, carboxylic acids and mercury. Snow photochemistry therefore affects the formation of ozone, a potent greenhouse gas, and of aerosols, which affect the radiative budget of the planet and, therefore, its climate. In parallel, microbiologists have investigated microbes in snow, identified and quantified species, and sometimes discussed their nutrient supplies and metabolism, implicitly acknowledging that microbes could modify snow chemical composition. However, it is only in the past 10 years that a small number of studies have revealed that microbial activity in cold snow (< 0 °C, in the absence of significant amounts of liquid water) could lead to the release of nitrogen oxides, halocarbons, and mercury into the atmosphere. I argue here that microbes may have a significant effect on snow and atmospheric composition, especially during the polar night when photochemistry is shut off. Collaborative studies between microbiologists and snow and atmospheric chemists are needed to investigate this little-explored field.


1987 ◽  
Vol 17 (11) ◽  
pp. 1313-1339 ◽  
Author(s):  
J. B. Harrington

The earth's climate is constantly changing. Climatic change is effected by many factors: the influence of continental drift, variations in solar intensity, volcanism, the impact of meteors and comets, changes in the earth's orbital parameters, ice accumulation and depletion, variations in oceanic circulations and chemistry, changes in terrestrial and aquatic life, and changes in atmospheric composition and circulation. Despite these influences, many of them large, and despite changes in the sun's radiant intensity over the past 4.5 billion years, the average temperature of the earth's surface has remained remarkably constant, hovering near 15 °C. This implies the presence of strong negative feedbacks reacting to any major environmental change. During the past century, man's influence on his environment has been increasing at an unprecedented rate. Under this influence, and particularly because of the effect of the so-called "greenhouse gases," the global mean temperature is expected to rise approximately 2.5 °C by the middle of the 21st century. There remains a degree of uncertainty in this prediction because of unresolved problems in estimating various positive and negative feedback mechanisms in air, earth, ocean, ice, and vegetation interaction and in the unknown magnitude of volcanic activity. The finest numerical models and the fastest computers are, at present, inadequate to resolve all of the problems. However, the best scientific evidence points to a return by the middle of the 21st century to a climate similar to that of the climatic optimum 5000–6000 years ago. The degree of confidence in the direction, speed, and magnitude of the impending climatic change is sufficient that affected agencies should be actively mapping strategies to respond most advantageously to the expected changes. This is particularly true of forestry in Canada where climatic changes are expected to be large and the lifetime of current plantings will extend well into the period of anticipated change.


Author(s):  
Leslie M. Loew

A major application of potentiometric dyes has been the multisite optical recording of electrical activity in excitable systems. After being championed by L.B. Cohen and his colleagues for the past 20 years, the impact of this technology is rapidly being felt and is spreading to an increasing number of neuroscience laboratories. A second class of experiments involves using dyes to image membrane potential distributions in single cells by digital imaging microscopy - a major focus of this lab. These studies usually do not require the temporal resolution of multisite optical recording, being primarily focussed on slow cell biological processes, and therefore can achieve much higher spatial resolution. We have developed 2 methods for quantitative imaging of membrane potential. One method uses dual wavelength imaging of membrane-staining dyes and the other uses quantitative 3D imaging of a fluorescent lipophilic cation; the dyes used in each case were synthesized for this purpose in this laboratory.


GeroPsych ◽  
2011 ◽  
Vol 24 (3) ◽  
pp. 143-154 ◽  
Author(s):  
Elmar Gräßel ◽  
Raffaela Adabbo

The burden of caregivers has been intensively researched for the past 30 years and has resulted in a multitude of individual findings. This review illustrates the significance of the hypothetical construct of perceived burden for the further development and design of the homecare situation. Following explanations regarding the term informal caregiver, we derive the construct burden from its conceptual association with the transactional stress model of Lazarus and Folkman. Once the extent and characteristics of burden have been set forth, we then present the impact of perceived burden as the care situation. The question of predictors of burden will lead into the last section from which implications can be derived for homecare and relief of caregivers.


2004 ◽  
Vol 34 (136) ◽  
pp. 339-356
Author(s):  
Tobias Wölfle ◽  
Oliver Schöller

Under the term “Hilfe zur Arbeit” (aid for work) the federal law of social welfare subsumes all kinds of labour disciplining instruments. First, the paper shows the historical connection of welfare and labour disciplining mechanisms in the context of different periods within capitalist development. In a second step, against the background of historical experiences, we will analyse the trends of “Hilfe zur Arbeit” during the past two decades. It will be shown that by the rise of unemployment, the impact of labour disciplining aspects of “Hilfe zur Arbeit” has increased both on the federal and on the municipal level. For this reason the leverage of the liberal paradigm would take place even in the core of social rights.


TAPPI Journal ◽  
2018 ◽  
Vol 17 (09) ◽  
pp. 519-532 ◽  
Author(s):  
Mark Crisp ◽  
Richard Riehle

Polyaminopolyamide-epichlorohydrin (PAE) resins are the predominant commercial products used to manufacture wet-strengthened paper products for grades requiring wet-strength permanence. Since their development in the late 1950s, the first generation (G1) resins have proven to be one of the most cost-effective technologies available to provide wet strength to paper. Throughout the past three decades, regulatory directives and sustainability initiatives from various organizations have driven the development of cleaner and safer PAE resins and paper products. Early efforts in this area focused on improving worker safety and reducing the impact of PAE resins on the environment. These efforts led to the development of resins containing significantly reduced levels of 1,3-dichloro-2-propanol (1,3-DCP) and 3-monochloropropane-1,2-diol (3-MCPD), potentially carcinogenic byproducts formed during the manufacturing process of PAE resins. As the levels of these byproducts decreased, the environmental, health, and safety (EH&S) profile of PAE resins and paper products improved. Recent initiatives from major retailers are focusing on product ingredient transparency and quality, thus encouraging the development of safer product formulations while maintaining performance. PAE resin research over the past 20 years has been directed toward regulatory requirements to improve consumer safety and minimize exposure to potentially carcinogenic materials found in various paper products. One of the best known regulatory requirements is the recommendations of the German Federal Institute for Risk Assessment (BfR), which defines the levels of 1,3-DCP and 3-MCPD that can be extracted by water from various food contact grades of paper. These criteria led to the development of third generation (G3) products that contain very low levels of 1,3-DCP (typically <10 parts per million in the as-received/delivered resin). This paper outlines the PAE resin chemical contributors to adsorbable organic halogens and 3-MCPD in paper and provides recommendations for the use of each PAE resin product generation (G1, G1.5, G2, G2.5, and G3).


1996 ◽  
Vol 35 (2) ◽  
pp. 189-190
Author(s):  
Mir Annice Mahmood

This book, hereinafter referred to as the Guide, has been developed for those social analysts (e.g., anthropologists, sociologists, and human geographers) who have had little or no practical experience in applying their knowledge as development practitioners. In the past, development projects would be analysed from a narrow financial and economic perspective. But with the evolution of thinking on development, this narrow financial and economic aspect has now been broadened to include the impact on society as the very meaning of development has now come to symbolise social change. Thus, development is not restricted only to plans and figures; the human environment in its entirety is now considered for analysis while designing and implementing development projects.


2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Turkan Ahmet

The past few decades of ongoing war in Iraq has had a dramatic impact on the health of Iraq’s population. Wars are known to have negative effects on the social and physical environments of individuals, as well as limit their access to the available health care services. This paper explores the personal experiences of my family members, who were exposed to war, as well as includes information that has been reviewed form many academic sources. The data aided in providing recommendations and developing strategies, on both local and international levels, to improve the health status of the populations exposed to war.


2020 ◽  
Vol 4 ◽  
pp. 78-95
Author(s):  
A.R. Ivanova ◽  
◽  
E.N. Skriptunova ◽  
N.I. Komasko ◽  
A.A. Zavialova ◽  
...  

A review of literature on the impact of dust and sand storms on the air transport operation is presented. Observational data on dust storms at the aerodromes of European Russia for the period of 2001-2019 are analyzed. The seasonal variations in dust transport episodes at aerodromes and its relationship with visibility changes are discussed. The characteristics of dusty air masses and advection are given. It is concluded that the frequency of dust transfer episodes for the aerodromes under study has decreased over the past five years, except for Gumrak aerodrome (Volgograd). Keywords: dust storm, sand storm, aviation, visibility, seasonal variations, aerodrome оf European Russia


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