He is talking about Chematica — a computer network mapping millions of molecules and reactions in the known chemical universe. Organic synthetic chemists have questioned whether Chematica could herald a new era in synthesis planning, but Grzybowski is certain that such software will be an indispensable tool for making molecules. Researchers often have to recall reactions or mechanisms from memory and consult the literature to map out a synthesis.
Abstract Open in a separate window Mercury Hg is a global pollutant that affects human and ecosystem health. We synthesize understanding of sources, atmosphere-land-ocean Hg dynamics and health effects, and consider the implications of Hg-control policies.
Primary anthropogenic Hg emissions greatly exceed natural geogenic sources, resulting in increases in Hg reservoirs and subsequent secondary Hg emissions that facilitate its global distribution.
The ultimate fate of emitted Hg is primarily recalcitrant soil pools and deep ocean waters and sediments. A key link between inorganic Hg inputs and exposure of humans and wildlife is the net production of methylmercury, which occurs mainly in reducing zones in freshwater, terrestrial, and coastal environments, and the subsurface ocean.
Elevated human exposure to methylmercury primarily results from consumption of estuarine and marine fish. Developing fetuses are most at risk from this neurotoxin but health effects of highly exposed populations and wildlife are also a concern.
Integration of Hg science with national and international policy efforts is needed to target efforts and evaluate efficacy. Introduction The socio-economic consequences of mercury Hg contamination and exposure of humans and wildlife to methyl Hg CH3Hg have prompted policies and regulations to limit Hg releases from human activities and to control its transport within and among the atmosphere, freshwaters, the lithosphere, and the ocean at local, regional, and global scales.
As such we organize this synthesis around Hg health effects; Hg dynamics in the atmosphere, land and the oceans; and the implications for Hg policy; the topics of the conference plenary sessions.
We synthesize the current understanding of Hg and CH3Hg sources, transport and fate globally, and discuss the potential variation of CH3Hg exposure to changes in Hg emissions and other environmental perturbations, and impacts on human health and environmental quality.
We discuss the most current knowledge on 1 the scale of Hg emission impacts local-regional-global ; 2 the relative importance of geogenic vs anthropogenic emission sources; 3 the recovery response time for ecosystems after emission controls years-decades-centuries ; and 4 the chronic low dose health effects of dietary exposure of CH3Hg on human populations.
We consider the implications of this knowledge and remaining research gaps for Hg control policies legally binding or voluntary actions at regional and global scales. Mercury is a naturally occurring element, but has been directly mobilized by humans for thousands of years into aquatic and terrestrial ecosystems through mining, the use of Hg in precious metal extraction, its presence as a trace contaminant in many materials e.
The temporal and spatial scales of Hg transport in the atmosphere and its transfer to aquatic and terrestrial ecosystems depend primarily on its chemical and physical forms.
Following emission, elemental Hg Hg 0 can be transported long distances before oxidation and removal by particle and gas-phase dry deposition or scavenging by precipitation.
The atmospheric residence time of Hg 0 is several months to a year.
It is important to distinguish between primary and secondary emission sources of Hg. Primary sources, both natural and anthropogenic, transfer Hg from long-lived lithospheric reservoirs to the atmosphere. This Hg deposits to land and oceans.
Deposited Hg can be reduced to Hg 0 and then re-emitted. Re-emission processes represent secondary sources that exchange Hg among surface reservoirs using the atmosphere as a vehicle.
Primary sources increase the global pool of Hg in surface reservoirs, while secondary sources redistribute it among and within ecosystems.May 21, · On a global basis, a small fraction of soil Hg is transported by riverine fluxes largely in association with dissolved or particulate organic matter (Figure (Figure1), 1), but this can be an important pathway to coastal areas and to certain portions of the open oceans.
43,, timberdesignmag.com ‘Organic’ versus ‘born global’ External environment Managers’ mindset Internal environment Decision to internationalize Organic pathway Home market Born global pathway Home market Export market A Export market A Export market N Export market N Source: Adapted from Âijö et al.
The definition of a born global firm is “a business organization that, from inception, seeks to derive significant competitive advantage from the use of resources and the sale of outputs in multiple countries.” Many companies go global, but that does not make them born global firms.
May 21, · On a global basis, a small fraction of soil Hg is transported by riverine fluxes largely in association with dissolved or particulate organic matter (Figure (Figure1), 1), but this can be an important pathway to coastal areas and to certain portions of the open oceans.
43,, We include a discussion of the different mineralization pathways available as organic matter moves from soils, through inland waters to coastal systems and ultimately into open ocean environments.
We argue that there is strong commonality between aspects of OM transformation in both terrestrial and marine systems and that our respective. Globalization Theories - Download as Powerpoint Presentation .ppt), PDF File .pdf), Text File .txt) or view presentation slides online.
versus ‘born global’ External environment Managers’ mindset Internal environment Decision to internationalize Organic pathway Home market Born global pathway Home market Export market A Export.