A multilevel soliton communication system

A multilevel soliton communication system is proposed and assessed. In this system, at the transmitter end each channel transmits its data via fundamental solitons with a pre-specified amplitude (i.e., soliton width). At the receiver end we take advantage of the sensitive relationship between the amount or fundamental soliton self-wavelength shift and the width of the soliton in the subpicosecond region. We first compress the incoming soliton noises to the subpicosecond level and pass them through a short length of fiber at the end of which the pulses have become separated in the wavelength domain since each soliton, corresponding to a data channel, has experienced a different Raman self-wavelength shift. The channels are then easily separated by optical filters. We have derived the design constraint relations for such a system. We have then heuristically designed a 40 Gbs (four channels) system for a 1000 km propagation distance (total data-rate distance product of 40 Tb/km). Numerical simulations and noise analyses have verified the feasibility and practicality of the proposed system with very good design margins. The wavelength jitter is found to be much smaller than the desired filter spacing, and thus its contribution to the bit error rate is negligible. We also argue that the system is more tolerant to Gordon-Haus timing jitter than conventional TDM soliton systems. The system is all fiber and is, therefore very cost effective as it does not require sophisticated electro-optic and microwave circuits for demultiplexing. The system can potentially operate at much higher speeds than those achievable in conventional soliton systems and it can be used in parallel with WDM soliton system     

A robust timing synchronization design in OFDM systems?part I: low-mobility cases

In this paper we are interested in designing a robust timing synchronization algorithm for OFDM systems that utilize pilot-aided channel estimation. We first characterize the impact of timing errors on the performance of a pilot-aided OFDM system. We derive analytical expressions for average channel estimation error variance in the presence of timing errors in high delay spread fading environments. The derived expressions show that pilot-aided channel estimators are considerably sensitive to timing synchronization errors due to the impact of rotations in different bases. We then show how to utilize this sensitivity to design a robust timing synchronization algorithm, without training overhead. The proposed algorithm is a cross-block design that uses channel estimation information to improve timing synchronization. We confirm our analytical results by simulating the proposed algorithm in high delay spread fading environments. In this paper, i.e. part I, we focus on timing synchronization for low-mobility cases. The analysis and results are then extended to high-mobility applications in part II.     

Kinetic theory based CFD simulation of turbulent fluidization of FCC particles in a riser

The turbulent fluidization regime is characterized by the co-existence of a dense, bottom region and a dilute, top bed. A kinetic theory based CFD code with a drag corrected for clusters captured the basic features of this flow regime: the dilute and dense regions, high dispersion coefficients and a strong anisotropy. The computed energy spectrum captures the observed gravity wave and the Kolmogorov -5/3 law at high frequencies. The computed turbulent kinetic energy is close to the measurements for FCC particles. The CFD simulations compared reasonably well with the measured core-annular flow experiments at very high solid fluxes. The computed granular temperatures, solids pressures, FCC viscosities and frequencies of oscillations were close to measurements reported in the literature. The computations suggest that unlike for the flow of group B particles, the oscillations for the FCC particles in the center of the riser are primarily due to the oscillations of clusters and not due to oscillations of individual particles. Hence mixing is not on the level of individual particles.     

p53 nuclear protein expression is an independent prognostic marker in clinically localized prostate cancer patients undergoing radical prostatectomy

Immunohistochemical (IHC) staining for p53 protein nuclear expression was evaluated in archival paraffin-embedded radical prostatectomy specimens from 139 patients with clinically localized prostate cancer followed up from 1 to 8 (mean, 4) years. Elevated nuclear p53 protein expression was detected in 85 (61%) of 139 patients, being heterogeneous and focal in the majority of specimens. Only four specimens displayed homogeneous nuclear accumulation of p53 protein. Disease progression, most commonly prostate-specific antigen elevation, was noted in 46 (33%) patients, with 39 (85%) having positive p53 protein IHC stains. Conversely, 93 (67%) of 139 have not recurred, with 46 (49%) having positive p53. Of all 54 p53-negative patients, 47 (87%) have had no disease recurrence. An increased p53 protein IHC stain was associated with a higher pathological stage (T1 and T2, 51% versus >/=T3, 69%) and Gleason score 2-4, 17%; 5-7, 72%; and 8-10, 87.5%). Despite these associations, p53 IHC staining was an independent predictor of disease-free survival in a multivariate analysis of p53, age, race, stage, and grade. This study revealed that a majority of clinically localized prostate cancers heterogeneously express elevated nuclear levels of p53 protein in at least a subset of malignant cells, and that this expression is an independent predictor of disease progression in prostate cancer patients after radical prostatectomy.     

Toggle mechanisms: Dynamics and energy dissipationDynamik,reibung und energieverluste beim kniehebelgetriebe

The dynamic performance of a toggle mechanism is investigated. Particular attention is given to (i) the collapse of the toggle in the presence of Coulomb friction, and (ii) the effect of a varying periodic force on the mechanism with damped elastic coupling. For case (i), a method utilizing both equations of motion and the kinetostatic analysis is outlined to solve for frictional torque and it is concluded that the performance of the mechanism under the influence of Coulomb friction depends highly upon the input energy to the system. It is shown that there is an optimum impulse speed almost equal to a defined version of the quasi-natural frequency of the system which can minimize the energy loss. For case (ii), a dimensionless grouping in terms of the forcing amplitude and the parameters of the system is found for determining the stability of the system. An approximate analytical solution for the time history of motion under the assumed condition is obtained.     

Decentralized Communication-Aware Motion Planning in Mobile Networks: An Information-Gain Approach

In this paper we consider decentralized motion-planning in mobile cooperative networks in the presence of realistic stochastic communication links, including path-loss, fading and shadowing effects. We propose a communication-aware motion-planning strategy, where each node considers the information gained through both its sensing and communication when deciding on its next move. More specifically, we show how each node can predict the information gained through its communications, by online learning of link quality measures such as received Signal to Noise Ratio (SNR) and correlation characteristics, and combine it with the information gained through its sensing in order to build objective functions for motion planning. We show that in the presence of path loss, our proposed strategy can improve the performance drastically. We furthermore show that while uncorrelated low-SNR fading channels can ruin the overall performance, the natural randomization of uncorrelated channels can potentially help the nodes leave deep fade spots with small movements. We finally show that highly correlated deep fades, on the other hand, can degrade the performance drastically for a long period of time. We then propose a randomizing motion-planning strategy that can help the nodes leave highly correlated deep fades.     

Effect of cigarette smoke exposure on the growth of Streptococcus mutans and Streptococcus sanguis: an in vitro study.

The aim of the present study was to determine the effect of cigarette smoke on the growth of Streptococcus mutans and Streptococcus sanguis. The standard strains of S. mutans (ATCC 25175) and S. sanguis (ATCC 10556) were cultured on blood agar and incubated for 48 hr in three main environments: atmospheric air, carbon dioxide, and cigarette smoke. Kent gold 1(nicotine: 0.1 mg, tar: 1 mg), Kent lights (nicotine: 0.8 mg, tar: 9 mg) and Bahman (nicotine: 1 mg, tar: 13 mg) were the brands used in the present study. Afterwards, digital photographs of the colonies were taken and the diameter of colonies was measured. Data were analyzed using Post Hoc and General Linear Model statistical tests. Cigarette smoke and carbon dioxide environments significantly increased the growth of S. mutans. However, high nicotine/tar content cigarette smoke (Bahman) had the greatest impact on S. mutans and S. sanguis. The mutans/sanguis ratio, which was 0.71 in atmospheric air, increased to 1.07 in the presence of carbon dioxide. Kent gold 1, Kent lights, and Bahman demonstrated a mutans/sanguis ratio of 1, 0.84, and 0.98 respectively. In conclusion, it seems that the growth of S. sanguis and S. mutans is accelerated in the vicinity of cigarette smoke.     

Immunohistochemical and mutational analysis of the p53 tumour suppressor gene and the bcl-2 oncogene in primary testicular germ cell tumours

The role of p53 in testicular germ cell tumours is still contradictory based on the finding of immunohistochemical overexpression at the protein level, but lack of mutations at the DNA level. In addition, p53 wild-type activity has been demonstrated in cell culture experiments. Overexpression of the proto-oncogene bcl-2 might block p53-induced apoptosis and might inhibit p53 functional activity. To clarify the apparent paradox with respect to p53 overexpression and lack of mutations, an immunohistochemical and mutational analysis of p53 and bcl-2 in TGCT was performed. Ten normal testes, 52 CIS and 151 clinical stage I nonseminomatous GCTs were included in our study. A commercially available anti-p53 polyclonal rabbit antibody and an anti-bcl-2-mouse monoclonal antibody were used to stain the 5pm sections. Staining was assessed by counting at least 500 cells from the area of the most intense staining in each tumour cell type, and this was scored semiquantitatively for intensity of staining on a 4 point scale. In addition, 30 primary GCTs were included in the mutational analysis: areas with p53 overexpression were identified and microdissected prior to DNA extraction. p53 exons 5-8 were amplified by polymerase chain reaction (PCR) followed by single strand conformation polymorphism analysis. Templates demonstrating band shifts on SSCP were subjected to direct DNA sequence analysis. None of the normal testes, 32/52 (62%) CIS, and 142/151 (94%) germ cell tumours exhibited p53 overexpression. p53 expression was significantly lower in mature teratomas (0.8 +/- 0.2) than in other germ cell tumour components (2.8 +/- 1.2, p > 0.001). PCR-SSCP did not reveal any missense mutations or deletions for the p53 gene. Bcl-2 protein expression was observed in none of the normal testes, in none of the CIS, and in 14/151 (9.3%) germ cell tumours. 13/14 germ cell tumours demonstrated bcl-2 expression only in the glandular and stromal elements of their teratomatous components whereas all other components were negative for bcl-2. Our results--p53 overexpression, lack of p53 mutations, undetectable bcl-2--are consistent with recent in vitro studies. High susceptibility of testicular cancer to drug-induced apoptosis appears to be the result of wild-type p53 and lack of bcl-2. Radiation and chemotherapeutic insensitivity of mature teratomas might be the result of bcl-2 overexpression and lack of p53 overexpression. Therefore, chemoresistance to DNA damaging agents might be reflected by the expression of p53 and bcl-2 and it might be useful to evaluate p53 and bcl-2 in primary tumours and metastatic lesions in order to identify patients early with primary or secondary chemoresistance.     

Quantifying walking capability: a novel aggregated index based on spatial perspective and analyses

Urbanization and modernization of services in the world triggers decrement in the physical activities of citizens. The most common solution for this decrement is improving walking capacity in neighborhoods to engage the citizens in walking activity. In this research, a novel model is presented to quantify walkability based on several necessary criteria and indicators considering the physical and non-physical conditions. For this model, promising sciences, including GIS, RS, and MCDM, are utilized to compute indicators and aggregate them in the form of a spatial index in a central region of Tehran, Iran, at the neighborhood scale. For evaluating the result, the obtained walkability level is compared to the physical structure of neighborhoods, previous works, housing price along with some other socio-economic parameters, and municipal action plan in the neighborhoods. These evaluations show that the outcome of the proposed model is a robust tool for walkability planning.     

The Development of a New Sonic Correlation for UCS Estimation from Drilling Data

Abstract

One of the most important characteristics of rocks in drilling operations is unconfined rock strength (UCS), which is critical in different aspects of drilling operations. Several laboratory-based correlations have been generated for specific rocks to estimate UCS from physical properties (such as transient time, porosity, and Young's modulus) of the rocks. In drilling analysis, when UCS information is required and direct methods for estimation of UCS are not available, it is common to use correlations that have been developed for other formations with the same or similar lithology. Obviously, the results of estimations based on UCS correlations for other formations will not be accurate and can affect subsequent analyses. Therefore, it is highly recommended to generate a correlation for the formation of interest, though it is not always possible to reach this goal from experimental works on core samples retrieved from the formation.

In this study, a sonic correlation that shows that it can provide relatively better global estimation of UCS for limestone rocks is modified for one of the Iranian carbonate formations by determining new coefficients for the correlation based on drilling data. For this purpose, the drilling information recorded in mud logging data is analyzed to backward simulate the drilling process based on a modified penetration rate model and calculate the rock strengths of the formation. The apparent rock strength log generated from this calculation proceeds quality-controlled steps according to statistical and pattern recognition methods to eliminate the noises and fluctuations that normally exist while working with field data. Then, a new correlation is developed from the formation response to sonic logs and apparent rock strength log. Because this new correlation is originally generated for the formation of interest, UCS is estimated more accurately and analyses dependent on UCS show fewer errors.