Monodisperse granular flows often develop regions with hexagonal close packing of particles. We investigate this effect in a system of inelastic hard spheres driven from below by a "thermal" plate. Molecular dynamics simulations show, in a wide range of parameters, a close-packed cluster supported by a low-density region. Surprisingly, the steady-state density profile, including the close-packe...

Metabolic activity was measured in the laboratory at temperatures between 5 and -20 degrees C on the basis of incorporation of (14)C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 d...

Predicted increases in the length of the growing season as a result of climate change may more frequently expose high-elevation plants to severe frosts. Understanding the ability of these species to resist frosts during the growing season is essential for predicting how species may respond to changes in temperature regimes. Here, we assessed the freezing resistance of 24 species from the centra...

In this study, thermal conductivity of aloe was determined in the cooling process from 20°C to -11°C, and in the thawing process from -11°C to 20 °C using the tiny thermal probe method. The tiny thermal probe measurement system had the advantages of high accuracy, short test time, low temperature rise and little water removal and was found to give accurate and consistent experimental results. T...

Experimental study of the atomic mechanism in melting and freezing processes remains a formidable challenge. We report herein on a unique material system that allows for in situ growth of bismuth nanoparticles from the precursor compound SrBi2Ta2O9 under an electron beam within a high-resolution transmission electron microscope (HRTEM). Simultaneously, the melting and freezing processes within ...

Laboratory experiments show that undercooling to about -5 degrees C occurs in colonized Beacon sandstones of the Ross Desert, Antarctica. High-frequency temperature oscillations between 5 degrees C and -5 degrees C or -10 degrees C (which occur in nature on the rock surface) did not damage Hemichloris antarctica. In a cryomicroscope, H. antarctica appeared to be undamaged after slow or rapid ...

Water that remains unfrozen at temperatures below the equilibrium bulk freezing temperature, in the presence of ice, is sometimes called unfreezable or bound. This paper analyses the phenomenon in terms of quantitative measurements of the hydration interaction among membranes or macromolecules at freezing temperatures. These results are related to analogous measurements in which osmotic stress ...

Introduction: Freezing of gait, a common PD motor symptom, could increase the risk of falling. This study aimed to investigate the clinimetric attributes of the Freezing of Gait Questionnaire (FOGQ) for people with Parkinson disease in the “off” state. Methods: A total of 115 patients with Parkinson disease (PD; mean age, 60.25 years) were included. Acceptability, internal consistency (by the ...