As an effective modeling, analysis and computational tool, graph theory is widely used in biological mathematics to deal with various biology problems. In the field of microbiology, graph can express the molecular structure, where cell, gene or protein can be denoted as a vertex, and the connect element can be regarded as an edge. In this way, the biological activity characteristic can be measured via topological index computing in the corresponding graphs. In our article, we mainly study the biology features of biological networks in terms of eccentric topological indices computation. By means of graph structure analysis and distance calculating, the exact expression of several important eccentric related indices of hypertree network and tree are determined. The conclusions we get in this paper illustrate that the bioengineering has the promising application prospects.

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In theoretical chemistry, the researchers use graph models to express the structure of molecular, and the Zagreb indices and redefined Zagreb indices defined on molecular graph G are applied to measure the chemical characteristics of compounds and drugs. In this paper, we present the exact expressions of redefined Zagreb indices for certain important chemical structures like nanotube and nanostar. As supplement, the redefined Zagreb indices of polyomino chain and benzenoid series are manifested.

We select 48 multiflare gamma-ray bursts (GRBs) (including 137 flares) from the Swift/XRT database and estimate the spectral lag with the discrete correlation function. It is found that 89.8% of the flares have positive lags and only 9.5% of the flares show negative lags when fluctuations are taken into account. The median lag of the multiflares (2.75 s) is much greater than that of GRB pulses (0.18 s), which can be explained by the fact that we confirm that multiflare GRBs and multipulse GRBs have similar positive lag–duration correlations. We investigate the origin of the lags by checking the E peak evolution with the two brightest bursts and find the leading models cannot explain all of the multiflare lags and there may be other physical mechanisms. All of the results above reveal that X-ray flares have the same properties as GRB pulses, which further supports the observation that X-ray flares and GRB prompt-emission pulses have the same physical origin.

Needs and requirements for optical interconnects in next generation servers are outlied. Related results on equalizing and characterizing high speed multimode links, building and testing parallel I2xlOGbit/sec transceivers, and highly parallel silicon photodetectors are presented. 2 4 INTERCONNECT NEEDS AND REQUIREMENTSBecause of their ability to transport data at high speeds over long distances, optical fibers move the bulk of information in backbone networks. Because of the high cost of installing and maintaining the fibers in the gmund, high cost transceivers are acceptable, and single mode fibers (SMFs) and highly wavelength stable lasers are used.Since the mid-l9Ws, optics has also made increasing inroads into the LAN and SAN environments. In these environments, standards such as Ethemet, Fibre Channel, and Infiniband predominate. Here multimode fiber (MMF) l i are mainly used because the cost of the transceivers is much lower than single mode. There is a large base of installed MMF in buildings and on campuses, and there is a desire to continue to use that fiber but at higher aggregate data rates. The distance for such premises wiring is up to 550 m, but few existing MMF /transceiver combinations support this distance at 10GbitIsec. The cost of Dense WDM transceivers is generally prohibitive for these applications, and DWDM requires SMFs. Higher aggregate bandwidth could be achieved using Coarse WDM on MMF fihers, for which standards exist, but products have not been widely offered by manufacturers or accepted by users for a variety of technical and cost reasons.The above uses for optics are "outside the box". At the present time, server and switch-router designers are seriously looking at using optics "inside the box" to enable higher connectivity within the system. In general, the needed communication bandwidth inside high-end systems is increasing about 3X every 2 years. The bandwidth increases faster tban other performance metrics in the system, such as clock speed and number of microprocessors (both of which are increasing at about 2X every 2 years) as the needed bandwidth is the product of these other m h c s , with some relief coming from larger caches and better system software design. By 2010, high end servers are expected to require -4OTerabitslsec of interconnection between internal nodes, where a node is a microprocessor and its associated cache. Presently, copper interconnects are used in these systems, but optics should gradually replace copper cables (initially) and then circuit hoard traces (later) in many of the interconnects, provided the technology and cost are acceptable. The primary advantages of optics over copper come from the higher bitrate per l i and the higher density of links for optics. The cost of optics, at 10-IOOX that of copper interconnects is a major roadblock. The 1OX figure is for fiber optics compared to electrical cables at -1Ometer lenghts, and the lOOX figure is fiber compared to copper circuit board traces and backplane connectors. Additional issues slowing the acce...

In this paper, we have collected the available observation data of BL Lac S5 0716+714 in I-band from published literature during 1994 to 2000. The light curve shows S5 0716+714 is very active and very complicated non-sinusoidal variations. We studied its mediumtimescale periodicity using the Jurkevich and power spectrum method to search for the possible medium-timescale periods and found that one possible medium-timescale periodic with a period of around 14±0.1 day is obtained for S5 0716+714. It is interesting to note that these results are in good agreement with the previous results by Impey et al. (2000) and Qian et al. (2002), and this work provides a new analysis and evidence of the medium-timescale periodicity in BL Lac S5 0716+714. The helical jet model seems to be more reasonable for explaining our results than other models.

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