A multi-causal model of mass extinctions: Increase in trace metals in the oceans

2005 ◽  
pp. 45-55 ◽  
Author(s):  
Paul N. Leary ◽  
Michael R. Rampino
Keyword(s):  
Trace Metals ◽  
Causal Model ◽  
Mass Extinctions

XRF and PIXE Analysis of light and Dark Adapted Ocular Tissue

1982 ◽  
Vol 40 ◽  
pp. 190-191
Author(s):  
B. J. Panessa ◽  
H. W. Kraner ◽  
J. B. Warren ◽  
K. W. Jones
Keyword(s):  
Trace Metals ◽  
Pigment Epithelium ◽  
Nerve Impulse ◽  
Light Response ◽  
Ocular Tissue ◽  
Emission Spectrometry ◽  
Retinol Dehydrogenase ◽  
Pixe Analysis ◽  
X Ray ◽  
Optimal Function

During photoexcitation the retina requires specific electrolytes and trace metals for optimal function (Na, Mg, Cl, K, Ca, S, P, Cu and Zn). According to Hagins (1981), photoexcitation and generation of a nerve impulse involves the movement of Ca from the rhodopsin-ladened membranes of the rod outer segment (ROS) to the plasmalemma, which in turn decreases the in-flow of Na into the photoreceptor, resulting in hyperpolarization. In toad isolated retinas, the presence of Ba has been found to increase the amplitude and prolong the delay of the light response (Brown and Flaming, 1978). Trace metals such as Cu, Zn and Se are essential for the activity of the metalloenzymes of the retina and retina pigment epithelium (RPE) (i.e. carbonic anhydrase, retinol dehydrogenase, tyrosinase, glutathione peroxidase, superoxide dismutase...). Therefore the content and fluctuations of these elements in the retina and choroid are of fundamental importance for the maintenance of vision. This paper presents elemental data from light and dark adapted frog ocular tissues examined by electron beam induced x-ray microanalysis, x-ray fluorescence spectrometry (XRF) and proton induced x-ray emission spectrometry (PIXE).

Identifying Sources of Sulfate Aerosols Reaching Whiteface Mountain, NY

1985 ◽  
Vol 43 ◽  
pp. 98-101
Author(s):  
James S. Webber
Keyword(s):  
Trace Metals ◽  
Acid Deposition ◽  
Surface Waters ◽  
Dry Deposition ◽  
Coal Combustion ◽  
Public Awareness ◽  
Sulfate Aerosols ◽  
Wet And Dry Deposition ◽  
Whiteface Mountain ◽  
Toxic Trace Metals

INTRODUCTION“Acid rain” and “acid deposition” are terms no longer confined to the lexicon of atmospheric scientists and 1imnologists. Public awareness of and concern over this phenomenon, particularly as it affects acid-sensitive regions of North America, have increased dramatically in the last five years. Temperate ecosystems are suffering from decreased pH caused by acid deposition. Human health may be directly affected by respirable sulfates and by the increased solubility of toxic trace metals in acidified waters. Even man's monuments are deteriorating as airborne acids etch metal and stone features.Sulfates account for about two thirds of airborne acids with wet and dry deposition contributing equally to acids reaching surface waters or ground. The industrial Midwest is widely assumed to be the source of most sulfates reaching the acid-sensitive Northeast since S02 emitted as a byproduct of coal combustion in the Midwest dwarfs S02 emitted from all sources in the Northeast.

Support, stress, and recovery from coronary heart disease: A longitudinal causal model.

1989 ◽  
Vol 8 (2) ◽  
pp. 175-193 ◽  
Author(s):  
Alan F. Fontana ◽  
Robert D. Kerns ◽  
Roberta L. Rosenberg ◽  
Kathleen L. Colonese
Keyword(s):  
Coronary Heart Disease ◽  
Heart Disease ◽  
Causal Model

Job satisfaction and social comparison: A causal model

2009 ◽  
Author(s):  
Joshua Douglas Cotton ◽  
Ronald S. Landis
Keyword(s):  
Job Satisfaction ◽  
Social Comparison ◽  
Causal Model

Why big eruptions don't always fuel mass extinctions

Nature ◽  
2009 ◽  
Author(s):  
Matt Kaplan
Keyword(s):  
Mass Extinctions ◽  
Fuel Mass

Quantification and localization of trace metals in natural plankton cells using a synchrotron X-ray fluorescence microprobe

2003 ◽  
Vol 104 ◽  
pp. 435-438 ◽  
Author(s):  
B. S. Twining ◽  
S. B. Baines ◽  
N. S. Fisher ◽  
C. Jacobsen ◽  
J. Maser
Keyword(s):  
Trace Metals ◽  
X Ray

Imaging and quantification of trace metals in thin biological specimens using microprobe techniques: Synchrotron induced X-ray fluorescence microprobe and nuclear microprobe

2003 ◽  
Vol 104 ◽  
pp. 321-324 ◽  
Author(s):  
T. Pinheiro ◽  
L. C. Alves ◽  
A. Barreiros ◽  
F. Araujo ◽  
S. Bohic ◽  
...  
Keyword(s):  
Trace Metals ◽  
Nuclear Microprobe ◽  
X Ray
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