Investigating biocomplexity through the agent-based paradigm.

Capturing the dynamism that pervades biological systems requires a computational approach that can accommodate both the continuous features of the system environment as well as the flexible and heterogeneous nature of component interactions. This presents a serious challenge for the more traditional mathematical approaches that assume component homogeneity to relate system observables using mathematical equations. While the homogeneity condition does not lead to loss of accuracy while simulating various continua, it fails to offer detailed solutions when applied to systems with dynamically interacting heterogeneous components. As the functionality and architecture of most biological systems is a product of multi-faceted individual interactions at the sub-system level, continuum models rarely offer much beyond qualitative similarity. Agent-based modelling is a class of algorithmic computational approaches that rely on interactions between Turing-complete finite-state machines--or agents--to simulate, from the bottom-up, macroscopic properties of a system. In recognizing the heterogeneity condition, they offer suitable ontologies to the system components being modelled, thereby succeeding where their continuum counterparts tend to struggle. Furthermore, being inherently hierarchical, they are quite amenable to coupling with other computational paradigms. The integration of any agent-based framework with continuum models is arguably the most elegant and precise way of representing biological systems. Although in its nascence, agent-based modelling has been utilized to model biological complexity across a broad range of biological scales (from cells to societies). In this article, we explore the reasons that make agent-based modelling the most precise approach to model biological systems that tend to be non-linear and complex

Digital Libraries: Selection of Materials for Scanning

Digitisation of documents is becoming a major activity in libraries and archives in the world. The libraries and archives that contain some of the valuable resources are either beginning to digitise their documents or trying to find resources to do so. The very activity of digitisation makes the job an activity that has both local as well as global implications

Schwarzschild horizon dynamics and SU(2) Chern-Simons theory

We discuss the effect of different choices in partial gauge fixing of bulk local Lorentz invariance, on the description of the horizon degrees of freedom of a Schwarzschild black hole as an SU(2) Chern-Simons theory with specific sources. A classically equivalent description in terms of an ISO(2) Chern-Simons theory is also discussed. Further, we demonstrate that both these descriptions can be partially gauge fixed to a horizon theory with U(1) local gauge invariance, with the solder form sources being subject to extra constraints in directions orthogonal to an internal vector field left invariant by U(1) transformations. Seemingly disparate approaches on characterization of the horizon theory for the Schwarzschild black hole (as well as spherical Isolated Horizons in general) are thus shown to be equivalent physically.Comment: 22 pages Latex, no figures, version accepted for publication in Physical Review

On further improvement of the techinque of evaluating summer institutes

Data from an earlier study are reanalyzed to improve upon the evaluation measures of summer institutes. The Summer Institute Efficiency Index is improved by using weighted geometric mean using different ranks as weights for the several dimensions. The coverage utility index is improved by taking the ratings given by all the participants

Progressive Hypertrophic Genital Herpes in an HIV-Infected Woman despite Immune Recovery on Antiretroviral Therapy

Most HIV-infected individuals are coinfected by Herpes simplex virus type 2 (HSV-2). HSV-2 reactivates more frequently in HIV-coinfected individuals with advanced immunosuppression, and may have very unusual clinical presentations, including hypertrophic genital lesions. We report the case of a progressive, hypertrophic HSV-2 lesion in an HIV-coinfected woman, despite near-complete immune restoration on antiretroviral therapy for up to three years. In this case, there was prompt response to topical imiquimod. The immunopathogenesis and clinical presentation of HSV-2 disease in HIV-coinfected individuals are reviewed, with a focus on potential mechanisms for persistent disease despite apparent immune reconstitution. HIV-infected individuals and their care providers should be aware that HSV-2 may cause atypical disease even in the context of near-comlpete immune reconstitution on HAART

Calibration and validation of the crop growth model LINTUL for grain amaranth (Amaranthus sp.)

Grain amaranth, a C4 plant, is a promising pseudocereal due to its valuable grain components. Knowledge of crop growth parameters is crucial for the introduction of a new crop, and the use of a crop model can help to understand yield formation and yield limiting processes. The aim of the study was to parameterise and validate the model LINTUL for grain amaranth. Basically, LINTUL estimates dry matter production from daily intercepted radiation and light use efficiency under potential growth conditions, i. e. without occurrence of any other limiting factors. A field experiment with the A. hypochondriacus genotypes „Neuer Typ“ and „Anderer Typ“ was carried out under semiarid conditions in 2004 and 2005. Field data of individual years were used for parameterisation while independent observations of the other year allowed for cross-validation, respectively. The estimated light use efficiency ranged between 2.5 and 2.8 g MJ-1 (total biomass per accumulated PAR). Specific leaf area estimates were lower in observations of 2004 (0.014 m2 g-1) than in observations of 2005 (0.018 m2 g-1). The light extinction coefficient of both genotypes measured before heading was 1.1. The effective sum of temperature (above a given threshold of 8°C) to anthesis was 554°C d for the genotype „Neuer Typ“ and 640°C d for „Anderer Typ“ in both years. The effective sum of temperature to maturity was 1127°C d in 2004, and 1249°C d in 2005 independent of the genotype. Model predictions of total biomass agreed well (RMSE: 92 to 136 g m-2) with the observed biomass throughout the growing cycle including final harvest (between 749 and 1172 g m-2). The estimated grain yield over time (RMSE: 47 to 112 g m-2) matched the field observations including final grain yield (between 220 and 367 g m-2) with less accuracy. The leaf area index was overestimated throughout the growing cycle from heading onwards to seed filling. The sharp initial increase in grain yield was underestimated suggesting that currently produced assimilates could not meet the growth capacity of the young seeds but might be complemented by internal re-translocation of biomass

Adoption of recommended quality control practices by fish processing factories

Responses to mailed questionnaires from 31 fish processing factories revealed that for 55 recommended practices in quality control, the percentage of adopters varied from 21.43 to 100.The adoption index was not correlated to any of five variables studied. The mean adoption index did not differ significantly between five other criteria related to fish processing. Rate of rejection or reprocessing at the factory itself was highly correlated with the amount of water used per tonne of processed material