Aneuploidy index in blood: a potential marker for early onset, androgen response, and metastasis in human prostate cancer

OBJECTIVES: To investigate whether the frequency of chromosome abnormalities in peripheral blood lymphocytes defined as the aneuploidy index in blood (AnIB) can be used as a clinical marker of early age onset, androgen response, and metastasis in human prostate cancer. METHODS: Peripheral blood samples were collected from 80 patients with prostate cancer, and chromosome preparations were made from 72-hour cultures after mitotic block. The AnIB of 59 informative cases was compared with several parameters, including age at disease onset, Gleason grade of tumor, clinical stage of tumor, metastasis, and prostate-specific antigen (PSA) level. RESULTS: Patients with AnIB levels greater than 3 had a significantly higher incidence of metastasis (P = 0.022), androgen-independent disease (P = 0.002), and early age at disease onset (age at diagnosis less than 65 years) (P = 0.002) compared with the patients with lower AnIB (less than 3) levels. In addition, patients with AnIB levels greater than 5 had higher PSA levels (greater than 20 ng/mL) (P = 0.029) than patients with AnIB levels less than 5. CONCLUSIONS: Chromosome abnormalities can be detected in the peripheral lymphocytes of patients with prostate cancer, and AnIB can be used as an early diagnostic and predictive marker for prostate cancer metastasis and androgen-independent disease.     

A batch‐type time‐true ATM‐network simulator—design for parallel processing

This paper presents a new type of network simulator for simulating the call‐level operations of telecom networks and especially ATM networks. The simulator is a pure time‐true type as opposed to a call‐by‐call type simulator. It is also characterized as a batch‐type simulator. The entire simulation duration is divided into short time intervals of equal duration, t. During t, a batch processing of call origination or termination events is executed and the time‐points of these events are sorted. The number of sorting executions is drastically reduced compared to a call‐by‐call simulator, resulting in considerable timesaving. The proposed data structures of the simulator can be implemented by a general‐purpose programming language and are well fitted to parallel processing techniques for implementation on parallel computers, for further savings of execution time. We have first implemented the simulator in a sequential computer and then we have applied parallelization techniques to achieve its implementation on a parallel computer. In order to simplify the parallelization procedure, we dissociate the core simulation from the built‐in call‐level functions (e.g. bandwidth control or dynamic routing) of the network. The key point for a parallel implementation is to organize data by virtual paths (VPs) and distribute them among processors, which all execute the same set of instructions on this data. The performance of the proposed batch‐type, time‐true, ATM‐network simulator is compared with that of a call‐by‐call simulator to reveal its superiority in terms of sequential execution time (when both simulators run on conventional computers). Finally, a measure of the accuracy of the simulation results is given. Copyright © 2002 John Wiley & Sons, Ltd.     

Using object-oriented and literate-programming techniques for the development of a computational electromagnetics library

Code maintenance is perhaps the most time-consuming problem in developing source code for various purposes. The increased complexity of computational-electromagnetics (CEM) simulation software makes this task even more difficult and tedious. The current paper proposes a sophisticated approach for a significant performance improvement in CEM code-maintenance tasks, with the fusion of object-oriented and literate-programming techniques. A case study concerning the development of a CEM library is thoroughly analyzed and presented. Various aspects of computational efficiency have been examined in order to estimate the costs of developing object-oriented CEM programs. The aim of the analysis is to stress the advantages of the above-mentioned techniques, and to provide useful guidelines for effective implementation of CEM programs with reusable, extensible, self-documented source code.     

The extended connection‐dependent threshold model for call‐level performance analysis of multi‐rate loss systems under the bandwidth reservation policy

Firstly, we reviewed two extensions of the Erlang multi‐rate loss model, whereby we can assess the call‐level QoS of telecom networks supporting elastic traffic: (i) the extended Erlang multi‐rate loss model, where random arriving calls of certain bandwidth requirements at call setup can tolerate bandwidth compression while in service; and (ii) the connection‐dependent threshold model, where arriving calls may have several contingency bandwidth requirements, whereas in‐service calls cannot tolerate bandwidth compression. Secondly, we proposed a new model, the extended connection‐dependent threshold model. Calls may have alternative bandwidth requirements at call setup and can tolerate bandwidth compression while in service. We proposed a recurrent formula for the efficient calculation of link occupancy distribution and consequently call blocking probabilities, link utilization, and throughput per service class. Furthermore, in the proposed model, we incorporated the bandwidth reservation policy, whereby we can (i) equalize the call blocking probabilities of different service classes, (ii) guarantee specific QoS per service class, and (iii) implement different maximum bandwidth compression/expansion rate per service class so that the network supports both elastic and stream traffic. The accuracy of the new model is verified by simulation. Moreover, the proposed model performs better than the existing models. Finally, we generalize the proposed model by incorporating service classes with either random or quasi‐random arrivals. Copyright © 2011 John Wiley & Sons, Ltd.     

Congestion Probabilities in CDMA-Based Networks Supporting Batched Poisson Input Traffic

We propose a new multirate teletraffic loss model for the calculation of time and call congestion probabilities in CDMA-based networks that accommodate calls of different service-classes. The call arrival process follows a batched Poisson process, which is more “peaked” and “bursty” than the ordinary Poisson process. The call-admission-control policy is based on the partial batch blocking discipline. This policy accepts a part of the batch (one or more calls) and discards the rest, if the available resources are not enough to accept the whole batch. The proposed model takes into account multiple access interference, both the notion of local (soft) and hard blocking, the user’s activity, as well as interference cancellation. Although the analysis of the model does not lead to a product form solution of the steady state probabilities, we show that the call-level performance metrics, time and call congestion probabilities can be efficiently calculated based on approximate but recursive formulas. The accuracy of the proposed formulas are verified through simulation and found to be quite satisfactory. Comparison of the proposed model with that of Poisson input shows the necessity of the new model. We also show the consistency of the new model over changes of its parameters.     

Control of channel activity through a unique amino acid residue of a G protein-gated inwardly rectifying K+ channel subunit

G protein-gated inwardly rectifying K+ (GIRK) channels, which are important regulators of membrane excitability both in heart and brain, appear to function as heteromultimers. GIRK1 is unique in the GIRK channel family in that although it is by itself inactive, it can associate with the other family members (GIRK2-GIRK5) to enhance their activity and alter their single-channel characteristics. By generating a series of chimeras, we identified a phenylalanine residue, F137, in the pore region of GIRK1 that critically controls channel activity. F137 is found only in GIRK1, while the remaining GIRK channels possess a conserved serine residue in the analogous position. The single-point mutant GIRK4(S143F) behaved as a GIRK1 analog, forming multimers with GIRK2, GIRK4, or GIRK5 channels that exhibited prolonged single-channel open-time duration and enhanced activity compared with that of homomultimers. Expression of the corresponding GIRK1 (F137S) mutant alone resulted in appreciable channel activity with novel characteristics that was further enhanced upon coexpression with other GIRK subunits. Thus, although the F137 residue renders the GIRK1 subunit inactive, when combined with other GIRK heteromeric partners it alters their gating and contributes to their enhanced activity.     

System Performance of Transmit Diversity Methods and a Two Fixed-Beam System in WCDMA

Downlink transmit diversity modes for WCDMA together with a two fixed-beam antenna array system are compared relative to the single antenna sectorized system in a radio network simulator. The transmit diversity methods investigated are: space-time transmit diversity and closed-loop mode I transmit diversity. Frequency selective (COST 259) and flat fading channels are considered and their impact to speech-only and data-only services is evaluated. A third service, which highlights the system performance of the various advanced antennas, is also investigated.The results in this investigation point out that the diversity gain in flat fading channels is substantial. In frequency-selective fading, the benefits of fixed beam systems is encouraging, whereas transmit diversity methods (especially Space-Time Transmit Diversity) is unsatisfactory.     

A Differential Approach to Shape from Polarisation: A Level-Set Characterisation

International Journal of Computer Vision - Despite the longtime research aimed at retrieving geometrical information of an object from polarimetric imaging, physical limitations in the polarisation...     

Expectation maximization algorithms for MAP estimation of jumpMarkov linear systems

In a jump Markov linear system, the state matrix, observation matrix, and the noise covariance matrices evolve according to the realization of a finite state Markov chain. Given a realization of the observation process, the aim is to estimate the state of the Markov chain assuming known model parameters. Computing conditional mean estimates is infeasible as it involves a cost that grows exponentially with the number of observations. We present three expectation maximization (EM) algorithms for state estimation to compute maximum a posteriori (MAP) state sequence estimates [which are also known as Bayesian maximum likelihood state sequence estimates (MLSEs)]. The first EM algorithm yields the MAP estimate for the entire sequence of the finite state Markov chain. The second EM algorithm yields the MAP estimate of the (continuous) state of the jump linear system. The third EM algorithm computes the joint MAP estimate of the finite and continuous states. The three EM algorithms optimally combine a hidden Markov model (HMM) estimator and a Kalman smoother (KS) in three different ways to compute the desired MAP state sequence estimates. Unlike the conditional mean state estimates, which require computational cost exponential in the data length, the proposed iterative schemes are linear in the data length