Tag Archives: sand

Saharastaub statt Schneeflocken

Mitte der Woche zeigte sich in den ostdeutschen Mittelgebirgen
zumindest ein Hauch von Winter. Ein Tiefausläufer führte
vorübergehend polare Meeresluft heran, in der es dort oberhalb von
600 m 3 – 10 cm Neuschnee gab. Doch dieser Wintereinbruch ist schon
wieder vorbei. Ein kräftiges Skandinavienhoch, dessen Einflussbereich
fast über ganz Osteuropa reicht und mit sibirischer Kaltluft
angefüllt ist, blockiert wie ein Bollwerk die West-Ostzugbahn der
atlantischen Tiefdruckgebiete. Diese sibirische Kaltluft bleibt für
uns zunächst unerreichbar, denn die Tiefdruckgebiete müssen weit nach
Süden bis ins Mittelmeer ausweichen. Ihr Einflussbereich reicht am
Wochenende bis nach Nordafrika hinunter, dabei führen sie auf ihrer
Ostflanke mit einer südlichen Strömung Saharaluft in den Südosten
Deutschlands. Diese Luft ist mit Saharastaub angereichert. Im
Durchschnitt gelangt der Saharastaub innerhalb eines Jahres 5- bis
15-mal bis nach Mitteleuropa. Dabei werden in der Sahara die
Staubpartikel durch starke Winde in die Höhe gewirbelt und dann mit
einer kräftigen südlichen Höhenströmung über weite Strecken nach
Norden transportiert. (more…)

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Invasion in the Desert: Why Some Plant Species are Survivors

Max Li’s research could inform policies to promote sustainable native environments and curb the invasion of alien plant species.

Max Li, a University of Arizona doctoral student in the Department of Ecology and Evolutionary Biology, is studying mechanisms that determine how competing desert plants can coexist with each other and what factors can cause the destruction of this stable coexistence.

His research could help inform policies to curb the spread of invasive species. (more…)

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Force is the Key to Granular State-Shifting

Ever wonder why sand can both run through an hourglass like a liquid and be solid enough to support buildings? It’s because granular materials – like sand or dirt – can change their behavior, or state. Researchers from North Carolina State University have found that the forces individual grains exert on one another are what most affect that transition.

Physicists have explored the changing behavior of granular materials by comparing it to what happens in thermodynamic systems. In a thermodynamic system, you can change the state of a material – like water – from a liquid to a gas by adding energy (heat) to the system. One of the most fundamental and important observations about temperature, however, is that it has the ability to equilibrate: a hot cup of tea eventually cools to match the temperature of the room. (more…)

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MU Researcher Studies How Infants Compare Quantities

COLUMBIA, Mo. – Parents are often amazed at how fast their child grows and develops. New research at the University of Missouri has determined that the ability to quantify – even things that are hard to quantify, such as liquid – may develop much sooner than most parents realize. 

University of Missouri researcher Kristy vanMarle, an assistant professor in the Department of Psychological Sciences in the College of Arts and Science, has determined that contrary to what previous studies have shown, infants are able to quantify non-cohesive substances – like sand, water, or even Cheerios – as early as 10 months. As long as the difference between the two substances is large enough, vanMarle has found that infants will choose the larger amount, especially when it comes to food. (more…)

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