Evidence flow graph methods for validation and verification of expert systems

The results of an investigation into the use of evidence flow graph techniques for performing validation and verification of expert systems are given. A translator to convert horn-clause rule bases into evidence flow graphs, a simulation program, and methods of analysis were developed. These tools were then applied to a simple rule base which contained errors. It was found that the method was capable of identifying a variety of problems, for example that the order of presentation of input data or small changes in critical parameters could affect the output from a set of rules

Game of orbits: a gaming approach to Neptune’s discovery

One reason that the planet Neptune will be remembered for, is to do with the fact that it was the first planet whose existence was postulated before being observed. This was based on analysing deviations in Uranus' orbit. The present study gives a brief account of the history behind the discovery of Neptune, looking at the same, through the conflicting lenses of France and Britain. With this context established, the study then investigates deviations in Uranus' orbit (experimentally found to range from 10,100 km to 21,276,000 km), under a host of different conditions and orientations of the perturbing body (Neptune/Jupiter). This was accomplished using Universe Sandbox 2, which is a physics-based simulation software, presented on the gaming platform, Steam. The paper then examines what these deviations correspond to, as viewed from Earth, finding that the deviation angle ranges between 0.04 arc-seconds and 3.22 arc-seconds. The paper in this way, demonstrates how using games like Universe Sandbox 2, can aid in approaching problems that would be considered difficult to visualize using a purely mathematical approac

A geometric method to locate Neptune

We develop a direct geometric method to determine the orbital parameters and mass of a planet, and we then apply the method to Neptune using high-precision data for the other planets in the solar system. The method is direct in the sense that it does not involve curve fitting. This paper, thereby, offers a new pedagogical approach to orbital mechanics that could be valuable in a physics classroom

Discovering a celestial object using a non-parametric algorithm

We describe a method that does not use any orbital parameters, to arrive at the position and mass of a new celestial object, using high-precision orbital state vector data of the rest of the objects in the system. As an illustration of this approach, we rediscover Neptune with remarkable accuracy

An approximate superposition method to obtain a planet's orbit

We demonstrate that the deviation produced by one celestial object on the Keplerian orbit of another around the Sun is largely independent of the presence of the remaining ones. Hence, to calculate the net deviation of an object from its Keplerian orbit, we superpose the deviations produced by every other object. We show that this method will be useful when dealing with a system containing a large number of objects. As a demonstration, we apply our method to the solar system, with a particular focus on the orbit of Uranus

Incidence and risk factors for extensively drug-resistant tuberculosis in Delhi region.

BACKGROUND: India with a major burden of multidrug-resistant tuberculosis (MDR-TB) does not have national level data on this hazardous disease. Since 2006, emergence of extensively drug-resistant TB (XDR-TB) is considered a serious threat to global TB control. This study highlights the demographic and clinical risk factors associated with XDR-TB in Delhi. METHODS: The study was conducted during April 2007 to May 2010. Six hundred eleven MDR-TB suspects were enrolled from four tertiary care hospitals, treating TB patients in Delhi and the demographic details recorded. Sputum samples were cultured using rapid, automated liquid culture system (MGIT 960). Drug susceptibility testing (DST) for Rifampicin (RIF) and Isoniazid (INH) was performed for all positive M. tuberculosis (M.tb) cultures. All MDR-TB isolates were tested for sensitivity to second-line drugs [Amikacin (AMK), Capreomycin (CAP), Ofloxacin (OFX), Ethionamide (ETA)]. RESULTS/FINDINGS: Of 611, 483 patients were infected with MDR M. tuberculosis (M.tb) strains. Eighteen MDR-TB isolates (3.7%) were XDR M.tb strains. Family history of TB (p 0.045), socioeconomic status (p 0.013), concomitant illness (p 0.001) and previous intake of 2(nd) line injectable drugs (p 0.001) were significantly associated with occurrence of XDR-TB. Only two of the patients enrolled were HIV seropositive, but had a negative culture for M. tuberculosis. 56/483 isolates were pre-XDR M. tuberculosis, though the occurrence of pre-XDR-TB did not show any significant demographical associations. CONCLUSIONS: The actual incidence and prevalence rate of XDR-TB in India is not available, although some scattered data is available. This study raises a concern about existence of XDR-TB in India, though small, signaling a need to strengthen the TB control program for early diagnosis of both tuberculosis and drug resistance in order to break the chains of transmission

ASSIST - Patient satisfaction survey in postoperative pain management from Indian subcontinent

Introduction: To compare pain scores at rest and ambulation and to assess patient satisfaction between the different modalities of pain management at different time points after surgery. Settings and Design: The ASSIST (Patient Satisfaction Survey: Pain Management) was an investigator-initiated, prospective, multicenter survey conducted among 1046 postoperative patients from India. Material and Methods: Pain scores, patient's and caregiver's satisfaction toward postoperative pain treatment, and overall pain management at the hospital were captured at three different time points through a specially designed questionnaire. The survey assessed if the presence of acute pain services (APSs) leads to better pain scores and patient satisfaction scores. Statistical Analysis: One-way ANOVA was used to evaluate the statistical significance between different modalities of pain management, and paired t-test was used to compare pain and patient satisfaction scores between the APS and non-APS groups. Results: The results indicated that about 88.4% of patients reported postoperative pain during the first 24 h after surgery. The mean pain score at rest on a scale of 1–10 was 2.3 ± 1.8 during the first 24 h after surgery and 1.1 ± 1.5 at 72 h; the patient satisfaction was 7.9/10. Significant pain relief from all pain treatment was reported by patients in the non-APS group (81.6%) compared with those in the APS (77.8%) group (P < 0.0016). Conclusion: This investigator-initiated survey from the Indian subcontinent demonstrates that current standards of care in postoperative pain management remain suboptimal and that APS service, wherever it exists, is yet to reach its full potential

Comparison of clinical characteristics (categorical values) of MDR, p-XDR and XDR-TB isolates.

<p>P values were calculated using chi-square test, values <0.05 considerd as significant.</p><p>CXR = Chest X-Ray, MDR-TB = Multi Drug Resistant Tuberculosis, p-XDR-TB = Pre Extensively Drug Resistant Tuberculosis, XDR-TB = Extensively Drug Resistant Tuberculosis, FQS = Fluroquinolones, BCG =  Bacillus Calmette–Guérin.</p><p><b>Boldface</b> indicates statistically significant differences.</p

P value comparison of patients with history of previous intake of 2^nd line injectable drugs among MDR, p-XDR and XDR-TB isolates.

<p>P values were calculated using Fisher's exact test, values <0.05 considerd as significant.</p><p>MDR-TB = Multi Drug Resistant Tuberculosis, p-XDR-TB = Pre Extensively Drug Resistant Tuberculosis, XDR-TB = Extensively Drug Resistant Tuberculosis.</p><p><b>Boldface</b> indicates statistically significant differences.</p

Diagram shows the distribution of multidrug-resistant/pre-extensively drug-resistant and extensively drug-resistant <i>M. tuberculosis</i> isolates with additional resistance profile.

<p>Diagram shows the distribution of multidrug-resistant/pre-extensively drug-resistant and extensively drug-resistant <i>M. tuberculosis</i> isolates with additional resistance profile.</p