Development Of Real-Time System For Urban Flooding By Surcharge Of Storm Drainge And River Inundation

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Universal and nonuniversal scaling of transmission in thin random layered media

The statistics of transmission through random 1D media are generally presumed to be universal and to depend only upon a single dimensionless parameter, the ratio of the sample length and the mean free path, s=L/l. For s much larger than unity, the probability distribution function of the logarithm of transmission, P(ln T) is Gaussian with average value -s and variance 2s. Here we show in numerical simulations and optical measurements that in random binary systems, and most prominently in systems for which s less than unity, the statistics of transmission are universal for transmission near an upper cutoff of unity and depend upon the character of the discrete disorder near a lower cutoff. The universal behavior of P(ln T) closely resembles a segment of a Gaussian and arises in random binary media with as few as three binary layers. Above the lower cutoff, but below the crossover to a universal expression, the shape of P(ln T) also depends upon the reflectivity of the interface between the layers. For a given value of s, P(ln T) evolves towards a universal distribution given by random matrix theory in the dense weak scattering limit as the numbers of layers increases. P(ln T) found in simulations is compared to results of random matrix calculations in the dense weak scattering limit but with an imposed minimum in transmission. Optical measurements in stacks of glass coverslips are compared to random matrix theory, and differences are ascribed to transverse disorder in the layers.Comment: 7 pages, 7 figure

The variation of relative magnetic helicity around major flares

We have investigated the variation of magnetic helicity over a span of several days around the times of 11 X-class flares which occurred in seven active regions (NOAA 9672, 10030, 10314, 10486, 10564, 10696, and 10720) using the magnetograms taken by the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO). As a major result we found that each of these major flares was preceded by a significant helicity accumulation over a long period (0.5 to a few days). Another finding is that the helicity accumulates at a nearly constant rate and then becomes nearly constant before the flares. This led us to distinguish the helicity variation into two phases: a phase of monotonically increasing helicity and the following phase of relatively constant helicity. As expected, the amount of helicity accumulated shows a modest correlation with time-integrated soft X-ray flux during flares. However, the average helicity change rate in the first phase shows even stronger correlation with the time-integrated soft X-ray flux. We discuss the physical implications of this result and the possibility that this characteristic helicity variation pattern can be used as an early warning sign for solar eruptions

Productivity of Solar Flares and Magnetic Helicity Injection in Active Regions

The main objective of this study is to better understand how magnetic helicity injection in an active region is related to the occurrence and intensity of solar flares. We therefore investigate magnetic helicity injection rate and unsigned magnetic flux, as a reference. In total, 378 active regions are analyzed using $SOHO$/MDI magnetograms. The 24-hour averaged helicity injection rate and unsigned magnetic flux are compared with the flare index and the flare-productive probability in next 24 hours following an measurement. In addition, we study the variation of helicity over a span of several days around the times of the 19 flares above M5.0 which occurred in selected strong flare-productive active regions. The major findings of this study are: (1) for a sub-sample of 91 large active regions with unsigned magnetic fluxes in the range from 3 to 5 $\times$ 10$^{22}$ Mx, there is a difference in magnetic helicity injection rate between flaring active regions and non-flaring active regions by a factor of 2; (2) the $GOES$ C-flare-productive probability as a function of helicity injection displays a sharp boundary between flare-productive active regions and flare-quiet ones; (3) the history of helicity injection before all the 19 major flares displayed a common characteristic: a significant helicity accumulation of (3-45)$\times$ 10 $^{42}$ Mx$^2$ during a phase of monotonically increasing helicity over 0.5 to 2 days. Our results support the notion that helicity injection is important in flares, but it is not effective to use it alone for the purpose of flare forecast. It is necessary to find a way to better characterize the time history of helicity injection as well as its spatial distribution inside active regions.Comment: 22 pages, 5 figures, ApJ, in pres

Identification and purification of a soluble region of BubR1: a critical component of the mitotic checkpoint complex

The mitotic checkpoint complex (MCC) ensures the fidelity of chromosomal segregation, by delaying the onset of anaphase until all sister chromatids have been properly attached to the mitotic spindle. In essence, this MCC-induced delay is achieved via the inhibition of the anaphase-promoting complex (APC). Among the components of the MCC, BubR1 plays two major roles in the functions of the mitotic checkpoint. First, BubR1 is able to inhibit APC activity, either by itself or as a component of the MCC, by sequestering a APC coactivator, known as Cdc20. Second, BubR1 activates mitotic checkpoint signaling cascades by binding to the centromere-associated protein E, a microtubule motor protein. Obtaining highly soluble BubR1 is a prerequisite for the study of its structure. BubR1 is a multi-domain protein, which includes a KEN box motif, a mad3-like region, a Bub3 binding domain, and a kinase domain. We obtained a soluble BubR1 construct using a three-step expression strategy. First, we obtained two constructs from BLAST sequence homology searches, both of which were expressed abundantly in the inclusion bodies. We then adjusted the lengths of the two constructs by secondary structure prediction, thereby generating partially soluble constructs. Third, we optimized the solubility of the two constructs by either chopping or adding a few residues at the C-terminus. Finally, we obtained a highly soluble BubR1 construct via the Escherichia coli expression system, which allowed for a yield of 10.8 mg/L culture. This report may provide insight into the design of highly soluble constructs of insoluble multi-domain proteins