The main goal of the research was to study the Pb pollution chronology. Dating of the core has allowed evaluating the time evolution of the gulf lead concentrations. Specific activities of Cs have also been measured in the sediment core sections as an independent confirmation of the chronology derived by the Pbex method. The time scale has then been used to correlate lead concentrations in core sections to estimated lead emissions in air due to gasoline combustion. A good correlation between the two data series has been obtained. Keywords Notes Acknowledgements This work has been partially supported by the Sicilian agency for environmental protection A. Schema geologico dei Monti di Palermo Sicilia. Google Scholar Abril, J. Dating of marine sediments by an incomplete mixing model. Journal of Environmental Radioactivity, 15, —
World Population Awareness
Protect Corals, Fish and Whales From Ocean Acidification April 4, , Center for Biological Diversity Without swift, national action to protect the ocean’s vast diversity of life from acidifying waters corals, shellfish, salmon and a whole host of beautiful creatures will be lost. We need your help to ask President Barack Obama and the Environmental Protection Agency to get working on a bold plan to curb ocean acidification.
Carbon dioxide pollution is also being absorbed by the ocean, causing its chemistry to change and become more acidic. This spells trouble for marine animals that are now having difficulty building shells, growing and sometimes even surviving in increasingly corrosive waters. Damian Carrington Seafood is the critical source of protein for more than 2. Official catch data from FAO rarely includes small-scale, sport or illegal fishing and does not count fish discarded at sea.
Particularly, the incomplete mixing within the top sediment zone (described through the Incomplete Mixing Zone model) can explain quantitatively and simultaneously the Cs peak and the flattening in the Pb activity profile. This is demonstrated using selected examples from literature data.
SHARE Although studying creativity is considered a legitimate scientific discipline nowadays, it is still a very young one. In the early s, a psychologist named J. Guilford was one of the first academic researchers who dared to conduct a study of creativity. He challenged research subjects to connect all nine dots using just four straight lines without lifting their pencils from the page. Today many people are familiar with this puzzle and its solution.
In the s, however, very few were even aware of its existence, even though it had been around for almost a century. If you have tried solving this puzzle, you can confirm that your first attempts usually involve sketching lines inside the imaginary square. The correct solution, however, requires you to draw lines that extend beyond the area defined by the dots.
Only 20 percent managed to break out of the illusory confinement and continue their lines in the white space surrounding the dots. The symmetry, the beautiful simplicity of the solution, and the fact that 80 percent of the participants were effectively blinded by the boundaries of the square led Guilford and the readers of his books to leap to the sweeping conclusion that creativity requires you to go outside the box.
The idea went viral via s-era media and word of mouth, of course. Overnight, it seemed that creativity gurus everywhere were teaching managers how to think outside the box. Management consultants in the s and s even used this puzzle when making sales pitches to prospective clients. Because the solution is, in hindsight, deceptively simple, clients tended to admit they should have thought of it themselves.
Late Precambrian Marine regression, anoxia, sluggish ocean, biological stress, etc. Nine major mass extinctions and their suggested cause or causes. Theories of dinosaur extinction Naturally, such a mystery as dinosaur extinction has spawned a wide range of theories, ranging from the plausible to the entertaining. As of , there were 60 theories for the cause of the ice age. Charlesworth, summarised ice age theories: One theory hypothesises that the climate became too wet, while another that the climate dried out to kill off the dinosaurs.
Marine sediment: Marine sediment, any deposit of insoluble material, primarily rock and soil particles, transported from land areas to the ocean by wind, ice, and rivers, as well as the remains of marine organisms, products of submarine volcanism, chemical precipitates from .
Article Abstract Pb geochronologies should be validated with independent tracers such as Cs. In the cases with constant Pb activity in the topmost sediments, the presence of a distinct Cs peak within the Pb plateau has been used as a definitive demonstration of acceleration increase in the sedimentation rate in recent years versus fast mixing. Nevertheless, some limitations can be identified in the use of semiquantitative arguments, and a global understanding of the whole Cs activity profile is then required.
Particularly, the incomplete mixing within the top sediment zone described through the Incomplete Mixing Zone model can explain quantitatively and simultaneously the Cs peak and the flattening in the Pb activity profile. This is demonstrated using selected examples from literature data. Nevertheless, they found 7Be only in the uppermost layer, the distinct Cs maximum at 6 cm depth, and undisturbed varves. The fast mixing seemed then opposed to common sense. The constant rate of supply model shows acceleration and it adequately matches the position of the Cs peak.
Nevertheless it fails to explain the whole Cs profile when handling time series of Cs atmospheric deposition. Finally, it is shown how the incomplete mixing of the activity through the pore water over a certain mass depth at the top sediment, with a finite value of the mixing coefficient, can quantitatively explain the whole activity versus mass depth profiles of Cs and Pb, and the presence of 7Be only in the uppermost sediment layer.
A further validation of these ideas is presented from other literature data. Dating of marine sediments by an incomplete mixing model.
Optically Stimulated Luminescence Dating of Sediments over the Past 200,000 Years
Uffizi, Florence Uffizi Gallery, Florence In the great part of renaissance and baroque history painting s, the figures, architectural elements and props were drawn from various monochrome drawings and afterward recomposed on a cartoon or on the canvas itself. Rarely, if ever, did the painter have the whole scene set up in his studio , to say nothing of outdoor scenes. Thus, we must presume that lighting was largely a factor of artistic invention and pictorial convention.
If a foreground repoussoir figure was represented immersed in a dark shadow with the background powerfully lit, it was not because the painter saw his scene this way in the moment he began paint, but because he either he had noted a similar effect in nature or he had copied the effect from another painting. It should always be remembered that the human eye is particularity forgiving with respect to lightning in the visual arts.
Is well known that some of the figures in certain woks of Rubens — are illuminated from the right, but in the same picture some receive light from the left, and yet this is generally not noticed.
The abyss of time. Geochronology by radioactive decay. The geologic age of the Mississippi River. Non-Poisson distributions observed during counting of certain carbon labeled organic sub monolayers. Is radioactive decay random? Bible-Science Newsletter 19 4: Observational paradoxes in extragalactic astronomy. Accretion rate of cosmic matter from iridium and osmium contents of deep-sea sediments.
The western and southern margins of the lake are fringed by the Eastern Ghats hill range. The lake has numerous islands. The larger islands, separated by shallow channels, lie between the barrier and the main body of the lake. Due to siltation , the width of the barrier has fluctuated and the mouth to the sea has periodically been closed. The location of the mouth has also frequently shifted, generally towards the northeast.
The mouth, which was 1.
Abstract. Isoleucine has been found to undergo a slow racemization reaction in a 5-meter sediment core taken from the Atlantis fracture zone (water depth, meters; actual location, 30°’N, 43°’W).
Help Keep the Winemaking Home Page a Free Website , a self-serving plea for support October 24th, I have not written anything here in a long time. I will not go into all the episodes of Murphy’s Law I have encountered, but suffice it to say they were numerous and often severe. Most recently, my health took a turn for the worse and a full diagnosis is still pending. However, I promised someone that I would post my recipe for Black Raspberry Chocolate Port the next time I posted anything, so that is the main event of this entry, followed by a reprint of an earlier piece on Dutched Cocoa Powder, an essential ingredient in the recipe.
Black Raspberry-Chocolate Port Black raspberries and Dutched chocolate make a great combination for a special port wine. I have long kept this recipe a secret-not because I didn’t want to share, but because I wanted something that was “just mine” and when I tasted this I knew it was the one. Over the years I have had so many requests for this recipe after I inadvertently mentioned it in a blog post that I had finally decided to share it in a future TidBitt entry, mainly to entice more people to subscribe to that now defunct enterprise.
I suppose the time has come. I have made it several ways, the easiest being using farm squeezed and filtered black raspberry juice. For me, it is also the most expensive since I have to buy the juice from afar and have it shipped to me. The recipe here is my first attempt using frozen black raspberries purchased as a rare find at a local supermarket. I bought the last five remaining 2-pound bags and made a wine and a port side by side using 5 pounds of berries in each.
The frozen berries were tied into fine-mesh nylon straining bags and left to thaw overnight and half of the next day in sealed primaries. The bags of pulp were also returned to the primaries and the primaries were again sealed.
The extinction of the dinosaurs
One of these was a series of buoys, each containing thermometers located ten feet above the water and at one foot below the water. The study found that water temperatures increased on average by 0. As of July , no similar study has been conducted on a global basis. The largest gap between any of the datasets in any year was 0. To determine whether 20th century warming is unusual, it is essential to place it in the context of longer-term climate variability.
Vertical mixing of lake sediments by tubificid oligochaetes was studied in laboratory experiments by using a radioactive (cesium labeled sediment) marker horizon. Dating of marine sediments by an incomplete mixing model, Journal of Environmental Radioactivity, /X(91) K,
An addendum to the Statement on Climate Change: Evidence from the Geological Record December The addendum is arranged such that some sections are unchanged from the original. For other sections additional information is provided, but this is not merged with the original content. Its is therefore not possible to read a single updated report.
Those who want to read the full addendum should simply use the link provided above. The Discussion in comments What I am soliciting in primary comments is informed opinion driven mainly by what data tells us, backed up by references to data sources. Primary comments may also take the form of questions. What I am not going to permit is social commentary and chit chat.
Comments will be strictly moderated.
The lithostratigraphy of the latest Triassic to earliest Cretaceous of the English Channel and its adjacent areas. Published by the Geological Society of London. It is a substantial paper 61 pages long with 26 diagrams.
Abstract. Within a more general study on marine sediments in the Gulf of Palermo (Sicily, Italy), the Pb ex dating method (using a model with constant sedimentation rate) has been applied to one sediment core. The main goal of the research was to study the Pb pollution chronology.
These profiles can be useful to test dating models, understood as particular solutions of a general advection—diffusion problem, if the time series of radionuclide inputs into the sediment is provided. A simple water-column model was used for this purpose, involving atmospheric fallout, measured distribution coefficient k d values, and a first-estimate of sedimentation rates.
These results provide some insight into the fate of atmospheric inputs to this marine environment and, particularly, into the contribution from the Chernobyl accident. They also thank colleagues from INRH for their assistance during sampling. References Abril JM a A new theoretical treatment of compaction and the advective—diffusive processes in sediments: J Environ Radioact Ilus E ed Dating of sediments and determination of sedimentation rate.