289 research outputs found
1881 and 1949 earthquakes at the Chios-Cesme Strait (Aegean Sea) and their relation to tsunamis
The most earthquake-prone areas in the eastern central Aegean Sea are the Izmir Bay, the Karaburun peninsula and the island of Chios. The level of seismic activity and tsunami potential are influenced by the presence of normal faults around the region. There have been about 20 moderate-size earthquakes from 496 BC to 1949 AD. Among these earthquakes, the ones on the dates 20 March 1389, 13 November 1856, 19/22 January 1866, 3 April 1881 and 23 July 1949 produced tsunamis. The Chios-Cesme earthquake (1881, Mw 6.5) took place in the South of the Cesme strait while the Chios-Karaburun earthquake (1949, Mw 6.7) occurred in the North. The tsunamis caused by the earthquakes affected the coasts of Chios Island and Cesme. These waves are thought to be associated with the earthquakes and co-seismic underwater failures possibly occurred along the coasts of the Chios Island and Karaburun Peninsula or on the complex subaqueous morphology between these lands. Some sea waves or oscillations observed following the aftershocks are believed to be related to other natural phenomena; e.g. the seiches occurred mainly in open-narrow bays as triggered by the earthquakes
Dynamic Heterogeneity and DNA Methylation in Embryonic Stem Cells
Cell populations can be strikingly heterogeneous, composed of multiple cellular states, each exhibiting stochastic noise in its gene expression. A major challenge is to disentangle these two types of variability and to understand the dynamic processes and mechanisms that control them. Embryonic stem cells (ESCs) provide an ideal model system to address this issue because they exhibit heterogeneous and dynamic expression of functionally important regulatory factors. We analyzed gene expression in individual ESCs using single-molecule RNA-FISH and quantitative time-lapse movies. These data discriminated stochastic switching between two coherent (correlated) gene expression states and burst-like transcriptional noise. We further showed that the “2i” signaling pathway inhibitors modulate both types of variation. Finally, we found that DNA methylation plays a key role in maintaining these metastable states. Together, these results show how ESC gene expression states and dynamics arise from a combination of intrinsic noise, coherent cellular states, and epigenetic regulation
Measuring single-cell gene expression dynamics in bacteria using fluorescence time-lapse microscopy
Quantitative single-cell time-lapse microscopy is a powerful method for analyzing gene circuit dynamics and heterogeneous cell behavior. We describe the application of this method to imaging bacteria by using an automated microscopy system. This protocol has been used to analyze sporulation and competence differentiation in Bacillus subtilis, and to quantify gene regulation and its fluctuations in individual Escherichia coli cells. The protocol involves seeding and growing bacteria on small agarose pads and imaging the resulting microcolonies. Images are then reviewed and analyzed using our laboratory's custom MATLAB analysis code, which segments and tracks cells in a frame-to-frame method. This process yields quantitative expression data on cell lineages, which can illustrate dynamic expression profiles and facilitate mathematical models of gene circuits. With fast-growing bacteria, such as E. coli or B. subtilis, image acquisition can be completed in 1 d, with an additional 1–2 d for progressing through the analysis procedure
First evidence of coherent meson production in neutrino-nucleus scattering
Neutrino-induced charged-current coherent kaon production,
, is a rare, inelastic electroweak process
that brings a on shell and leaves the target nucleus intact in its ground
state. This process is significantly lower in rate than neutrino-induced
charged-current coherent pion production, because of Cabibbo suppression and a
kinematic suppression due to the larger kaon mass. We search for such events in
the scintillator tracker of MINERvA by observing the final state ,
and no other detector activity, and by using the kinematics of the final state
particles to reconstruct the small momentum transfer to the nucleus, which is a
model-independent characteristic of coherent scattering. We find the first
experimental evidence for the process at significance.Comment: added ancillary file with information about the six kaon candidate
- …
