340 research outputs found
The lunar nomenclature: The reverse side of the moon (1961-1973)
The history of naming the details of the relief on the near and reverse sides of the moon is examined. The book contains lists of the names of craters of the reverse side of the moon in Russian and the Latin spellings
Landscape and geomorphic survey of Zhamanshin area, Northern Kazakhstan: Preliminary report on 1992 field trip data
The June 1992 geographical expedition to Zhamanshin crater area made a landscape and geomorphic survey of this impact structure. Observational points in the area of 300 sq km give new data on the geographical processes in the impact crater. The data obtained could be applied to search for unknown impact structures anywhere through the traces of such features in landscapes
Seasonal and Interannual Varialbility in Evapotranspiration of Native Tallgrass Prairie and Cultivated Wheat Ecosystems, by G.G. Burba, S.B. Verma
James N. Green est un historien qui a toujours eu des liens étroits avec le Brésil, comme chercheur, mais aussi antérieurement comme militant des droits de l’homme. En 1998, durant un colloque, il dut faire face à une désagréable question. Pourquoi, lui demanda-t-on, les universitaires états-uniens ont si peu fait pour dénoncer les atrocités du régime militaire brésilien entre les années 1960 et le début des années 1980 ? De fait, le gouvernement des États-Unis a soutenu le régime militaire e..
Eddy Covariance flux errors due to random and systematic timing errors during data acquisition
Modern eddy covariance (EC) systems collect
high-frequency data (10–20 Hz) via digital outputs of instru ments. This is an important evolution with respect to the tra ditional and widely used mixed analog/digital systems, as
fully digital systems help overcome the traditional limita tions of transmission reliability, data quality, and complete ness of the datasets
Russia's contribution to regional geologic mapping of Venus
Geologic maps in Magellan C1-format were produced by six geologists and three cartographer in Russia during 1992. More sheets are in progress. The work is coordinated by Vernadsky Institute. The Magellan SRR images in form of C1-format photomaps were used as a base for geologic-geomorphic regional mapping of Venus at approximately 1:8,000,000 scale. This work took place in Russia at Vernadsky Institute and at the Department of Geology, Lomonosov Moscow University. The aim is to produce a preliminary geologic survey of Venus with the new high resolution images obtained by Magellan. It took place at the cartographic division, Laboratory of Comparative Planetology and Meteoritics, Vernadsky Institute, Russsia's Academy of Sciences
Eddy covariance flux errors due to random and systematic timing errors during data acquisition
Modern eddy covariance (EC) systems collect high-frequency data (10–20 Hz)
via digital outputs of instruments.
This is an important evolution with respect to the traditional and widely
used mixed analog/digital systems, as fully digital systems help overcome
the traditional limitations of transmission reliability, data quality, and
completeness of the datasets.However, fully digital acquisition introduces a new problem for guaranteeing
data synchronicity when the clocks of the involved devices themselves cannot
be synchronized, which is often the case with instruments providing data via
serial or Ethernet connectivity in a streaming mode. In this paper, we
suggest that, when assembling EC systems in-house, aspects related to
timing issues need to be carefully considered to avoid significant flux
biases.By means of a simulation study, we found that, in most cases, random timing
errors can safely be neglected, as they do not impact fluxes significantly.
At the same time, systematic timing errors potentially arising in
asynchronous systems can effectively act as filters leading to significant
flux underestimations, as large as 10 %, by means of attenuation of
high-frequency flux contributions. We characterized the transfer function of
such filters as a function of the error magnitude and found cutoff
frequencies as low as 1 Hz, implying that synchronization errors can
dominate high-frequency attenuations in open- and enclosed-path EC systems.
In most cases, such timing errors neither be detected nor characterized
a posteriori. Therefore, it is important to test the ability of traditional
and prospective EC data logging systems to assure the required synchronicity
and propose a procedure to implement such a test relying on readily
available equipment.</p
Geological-morphological description of the Sedna and Guinevre planitiae on Venus (photomap sheets B-11, B-20, B-21)
Presented are descriptions and maps of the region of Sedna and Guinevra Planitiae--representatives of the largest geological providense on Venus comprised of volcanic rock. Units of different age are isolated and their relations are given, as well as interpretations of proposed mechanisms of formation
Relief and geology of the north polar region of the planet Venus
Description of topographic features is given for the North polar region of the planet Venus. Principal geomorphic types of terrain are characterized as well as their geologic relations. Relative ages of geologic units in Venus North polar region are discussed
miR-34a Promotes Vascular Smooth Muscle Cell Calcification by Downregulating SIRT1 (Sirtuin 1) and Axl (AXL Receptor Tyrosine Kinase).
Objective- Vascular calcification (VC) is age dependent and a risk factor for cardiovascular and all-cause mortality. VC involves the senescence-induced transdifferentiation of vascular smooth muscle cells (SMCs) toward an osteochondrogenic lineage resulting in arterial wall mineralization. miR-34a increases with age in aortas and induces vascular SMC senescence through the modulation of its target SIRT1 (sirtuin 1). In this study, we aimed to investigate whether miR-34a regulates VC. Approach and Results- We found that miR-34a and Runx2 (Runt-related transcription factor 2) expression correlates in young and old mice. Mir34a <sup>+/+</sup> and Mir34a <sup>-/-</sup> mice were treated with vitamin D, and calcium quantification revealed that Mir34a deficiency reduces soft tissue and aorta medial calcification and the upregulation of the VC Sox9 (SRY [sex-determining region Y]-box 9) and Runx2 and the senescence p16 and p21 markers. In this model, miR-34a upregulation was transient and preceded aorta mineralization. Mir34a <sup>-/-</sup> SMCs were less prone to undergo senescence and under osteogenic conditions deposited less calcium compared with Mir34a <sup>+/+</sup> cells. Furthermore, unlike in Mir34a <sup>+/+</sup> SMC, the known VC inhibitors SIRT1 and Axl (AXL receptor tyrosine kinase) were only partially downregulated in calcifying Mir34a <sup>-/-</sup> SMC. Strikingly, constitutive miR-34a overexpression to senescence-like levels in human aortic SMCs increased calcium deposition and enhanced Axl and SIRT1 decrease during calcification. Notably, we also showed that miR-34a directly decreased Axl expression in human aortic SMC, and restoration of its levels partially rescued miR-34a-dependent growth arrest. Conclusions- miR-34a promotes VC via vascular SMC mineralization by inhibiting cell proliferation and inducing senescence through direct Axl and SIRT1 downregulation, respectively. This miRNA could be a good therapeutic target for the treatment of VC
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