Laboratory simulation of the Mars atmosphere. A feasibility study

Feasibility of simulation of Martian atmospheric processes - atmospheric transportation and deposition of dust and sand, absorption properties, and thermodynamic propertie

Polar sea ice observations by means of microwave radiometry

Principles pertinent to the utilization of 1.55 cm wavelength radiation emanating from the surface of the earth for studying the changing characteristics of polar sea ice are briefly reviewed. Recent data obtained at that wavelength with an imaging radiometer on-board the Nimbus 5 satellite are used to illustrate how the seasonal changes in extent of sea ice in both polar regions may be monitored free of atmospheric interference. Within a season, changes in the compactness of the sea ice are also observed from the satellite. Some substantial areas of the Arctic sea ice canopy identified as first-year ice in the past winter were observed not to melt this summer, a graphic illustration of the eventual formation of multiyear ice in the Arctic. Finally, the microwave emissivity of some of the multiyear ice areas near the North Pole was found to increase significantly in the summer, probably due to liquid water content in the firm layer

Larkin-Ovchinnikov-Fulde-Ferrell phase in the superconductor (TMTSF)2ClO4: Theory versus experiment

We consider a formation of the Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) phase in a quasi-one-dimensional (Q1D) conductor in a magnetic field, parallel to its conducting chains, where we take into account both the paramagnetic spin-splitting and orbital destructive effects against superconductivity. We show that, due to a relative weakness of the orbital effects in a Q1D case, the LOFF phase appears in (TMTSF)$_2$ClO$_4$ superconductor for real values of its Q1D band parameters. We compare our theoretical calculations with the recent experimental data by Y. Maeno's group [S. Yonezawa et al., Phys. Rev. Lett. \textbf{100}, 117002 (2008)] and show that there is a good qualitative and quantitative agreement between the theory and experimental data.Comment: 4 pages, 1 figur

Application of Nimbus-6 microwave data to problems in precipitation prediction for the Pacific west coast

The preliminary results of a research study that emphasizes the analysis and interpretation of data related to total precipitable water and nonprecipitating cloud liquid water obtained from NIMBUS-6 SCAMS are reported. Sixteen cyclonic storm situations in the northeastern Pacific Ocean that resulted in significant rainfall along the west coast of the United States during the winter season October 1975 through February 1976 are analyzed in terms of their distributions and amounts of total water vapor and liquid water, as obtained from SCAMS data. The water-substance analyses for each storm case are related to the distribution and amount of coastal precipitation observed during the subsequent time period when the storm system crosses the coastline. Concomitant precipitation predictions from the LFM are also incorporated. Techniques by which satellite microwave data over the ocean can be used to improve precipitation prediction for the Pacific West Coast are emphasized

Detection of hidden mineral deposits by airborne spectral analysis of forest canopies

Data from field surveys and biogeochemical tests conducted in Maine, Montana, and Washington strongly correlate with results obtained using high resolution airborne spectroradiometer which detects an anomalous spectral waveform that appears definitely associated with sulfide mineralization. The spectral region most affected by mineral stress is between 550 nm and 750 nm. Spectral variations observed in the field occur on the wings of the red chlorophyll band centered at about 690 nm. The metal-stress-induced variations on the absorption band wing are most successfully resolved in the high spectral resolution field data using a waveform analysis technique. The development of chlorophyll pigments was retarded in greenhouse plants doped with copper and zinc in the laboratory. The lowered chlorophyll production resulted in changes on the wings of the chlorophyll bands of reflectance spectra of the plants. The airborne spectroradiometer system and waveform analysis remains the most sensitive technique for biogeochemical surveys

Mitochondrial trafficking in healthy and injured neurons

Mitochondria are the primary generators of ATP and are important regulators of intracellular calcium homeostasis. These organelles are dynamically transported along lengthy neuronal processes, presumably for appropriate distribution to cellular regions of increased need such as synapses. The removal of damaged mitochondria that produce harmful reactive oxygen species and promote apoptosis is also thought to be mediated by mitochondrial transport to autophagosomes. Mitochondrial trafficking is therefore important for maintaining neuronal and mitochondrial health while cessation of movement may lead to neuronal and mitochondrial dysfunctions.The demands for mitochondria differ between developing and mature neurons, and separate mitochondrial recruitment signals have been identified in each case. In the first aim, we examined how mitochondrial dynamics are affected by the development of synaptic connections in cortical neurons. We revealed reduced mitochondrial movement and elongated morphology in mature neurons which probably serve to optimize mitochondrial contact with synaptic sites.Synapses require mitochondria to supply ATP and regulate local [Ca2+]i for neurotransmission. The second aim investigated mitochondrial trafficking patterns relative to synaptic sites on axons and dendrites. We demonstrated that synapses are targets for long-term mitochondrial localization and dynamic recruitment of moving mitochondria, and that trafficking patterns are influenced by changes in synaptic activity. We also found that mitochondrial movement in dendrites is more severely impaired by neurotoxic glutamate and zinc exposures than in axons. These findings suggest a mechanism for postsynaptic dysfunction and dendritic degeneration in excitotoxicity.The third aim examined impaired mitochondrial transport as an early pathogenic mechanism in Huntington's disease. Recent studies indicate that aggregates composed of mutant huntingtin fragments hinder axonal transport by sequestering wildtype huntingtin, cytoskeletal components and molecular motors. Our studies in cortical neurons demonstrated reduced mitochondrial trafficking specifically to sites of aggregates and impeded passage of moving mitochondria by aggregates resulting in discrete regions of mitochondrial accumulation and immobilization.In summary, this dissertation provides new insight into our understanding of mitochondrial trafficking, morphology and distribution in cortical neurons that are developing, synaptically mature, acutely injured, and diseased. We conclude that mitochondrial movement is dynamic in healthy neurons and that injured neurons exhibit different manifestations of impaired movement

Study of quasi-distributed optical fiber methane sensors based on laser absorption spectrometry

The coal industry plays an important role in the economic development of China. With the increase of coal mining year by year, coal mine accidents caused by gas explosion also occur frequently, which poses a serious threat to the life safety of absenteeism and national property safety. Therefore, high-precision methane fiber sensor is of great significance to ensure coal mine safety. This paper mainly introduces two kinds of quasi-distributed gas optical fiber sensing systems based on laser absorption spectroscopy. The gas fiber optic sensor based on absorption spectrum has high measurement accuracy, fast response and long service life. One is quasi-distributed optical fiber sensing system based on spatial division multiplexing (SDM) technology and the other is quasi-distributed optical fiber sensing system based on optical time domain reflection and time division multiplexing(TDM) technology