Sampling-Based Query Re-Optimization

Despite of decades of work, query optimizers still make mistakes on "difficult" queries because of bad cardinality estimates, often due to the interaction of multiple predicates and correlations in the data. In this paper, we propose a low-cost post-processing step that can take a plan produced by the optimizer, detect when it is likely to have made such a mistake, and take steps to fix it. Specifically, our solution is a sampling-based iterative procedure that requires almost no changes to the original query optimizer or query evaluation mechanism of the system. We show that this indeed imposes low overhead and catches cases where three widely used optimizers (PostgreSQL and two commercial systems) make large errors.Comment: This is the extended version of a paper with the same title and authors that appears in the Proceedings of the ACM SIGMOD International Conference on Management of Data (SIGMOD 2016

A statistical approach to spectrum sensing using bayes factor and p-Values

The sensing methods with multiple receive antennas  in the Cognitive Radio (CR) device, provide a promising solution for reducing the error rates in the detection of the Primary User (PU) signal. The received Signal to Noise Ratio at the CR receiver is enhanced using the diversity combiners. This paper proposes a statistical approach based on minimum Bayes factors and p-Values as diversity combiners in the spectrum sensing scenario. The effect of these statistical measures in sensing the spectrum in a CR environment is investigated. Through extensive Monte Carlo simulations it is shown that this novel statistical approach based on Bayes factors provides a promising solution to combine the test statistics from multiple receiver antennas and can be used as an alternative to the conventional hypothesis testing methods for spectrum sensing. The Bayesian results provide more accurate results when measuring the strength of the evidence against the hypothesis

Anthelmintic Activity of Trikatu Churna and its Ingredients

The alcoholic extract of Trikatu churna and its ingredients were evaluated for anthelmintic activity. The dried fruits of Piper nigrum L. (Piperaceae), Piper longum L. (Piperaceae) and rhizome of Zingiber officinale Roscoe. (Zingiberaceae) were powdered and mixed together in equiproportions to get a polyherbal formulation, Trikatu churna. All these three ingredients are spicy, commonly used in our daily diet, also well known for their tremendous therapeutic potential, since from the Vedic period. The alcoholic extract of Trikatu churna and its ingredients were screened for preliminary phytochemical studies and also tested for anthelmintic activity against Pheritima posthuma and recorded the time taken for induction of paralysis and death. Piperazine citrate (10 mg/ml) was included as standard reference and distilled water as control. The results demonstrated that, the extracts of Trikatu churna and its plant ingredients showed the presence of alkaloids, flavonoids, tannins, lignins and steroids, these test samples were also exhibited potent anthelmintic activity, but the highest activity was noticed in Trikatu churna, this might be due to the multifunctional effect of all the three plant ingredients of Trikatu churna. Based on the above results, it is confirmed that, combination of Piper nigrum, Piper longum and Zingiber officinale in Trikatu churna offered promising anthelmintic effect than using the ingredients alone

A prospective study of treatment of distal femur fractures with locking condylar plate

Background: Multiple implants are available to treat distal femoral fractures. The recent addition is the locking plate contoured to the distal femur with combiholes in the proximal portion. Though it is established that locking plates offer higher stability than the previous implants like dynamic compression screw or condylar buttress plate, some studies showed higher incidence of delayed union. We evaluated 30 type A and type C distal femoral fractures treated with locking condylar plate in our institutes.Methods: We conducted a prospective study on 30 consecutive patients with fractures of distal femur operated with locking condylar plate from December, 2015 to February, 2017. Patients were regularly followed up with x-rays and clinical examination. At the end of one year follow-up, patients were evaluated with Pritchett score.Results: Fracture union was seen in all patients. Union was faster in type A fractures than in type C intra articular fractures. 67% of patients achieved excellent to good grading according to Pritchett rating system. Conclusions: Locking condylar plate is effective in treating distal femoral fractures with minimal complications

(R1511) Numerical Solution of Differential Difference Equations Having Boundary Layers at Both the Ends

In this paper, numerical solution of differential-difference equation having boundary layers at both ends is discussed. Using Taylor’s series, the given second order differential-difference equation is replaced by an asymptotically equivalent first order differential equation and solved by suitable choice of integrating factor and finite differences. The numerical results for several test examples are presented to demonstrate the applicability of the method

A study of age as a risk factor in ischemic stroke of elderly

Background: The aim of the study was to determine the effect of age as a risk factor and a determinant of outcome in elderly ischemic stroke patients.Methods: This is an observational study. One hundred, successive elderly patients aged 60 years and above, admitted with acute ischemic stroke in PESIMSR over a period of 18 months were prospectively studied. Patients with hemorrhagic stroke, neurological deficits following trauma or following infection were excluded. Demographics, risk factors, stroke severity at admission were estimated by NIHSS. Risk factors and clinical profile were noted and compared among male and female patients. Outcome at discharge was measured by-mRS-modified ranking score.Results: Patients in age group 60-75 years presented with less severe stroke and better mRS when compared to >75 years age group. Complications were significantly higher among the older age group.Conclusions: The risk factors identified for ischemic stroke in the present study are diabetes, hypertension, dyslipidaemia, obesity, smoking, and alcohol. Severity of stroke at presentation, clinical outcome and complication rate during the in-hospital stay were all significantly affected by the age, more so in ischemic stroke. Age specific factors of stroke prevention are crucial for successful prevention and implementation of well-organized stroke care

Cumulative and Residual Effects of Paclobutrazol on Growth, Yield and Fruit Quality of 'Alphonso' Mango

A field experiment was conducted during 1996 to 2002 at Indian Institute of Horticultural Research, Bangalore, to study the cumulative and residual effects of paclobutrazol (PBZ) application on shoot vigour, flowering and fruit yield of seventeen years old 'Alphonso' mango trees. Foliar sprays of the chemical at 500, 1000 or 2000 ppm or soil drench at 5 or 10 g a. i. per tree was given during September for three consecutive years and the residual effects were observed for three more subsequent years. Application of PBZ as soil drench was more effective than its foliar spray and doubled fruit yield during the six years. Chemical parameters of fruits such as TSS and acidity were not affected by the treatments but average weight of a fruit was less in the case of PBZ treatments. Residual influence of this chemical, when applied as soil drench, persisted in the three years following the discontinuation of application for three consecutive years, indicating the scope for skipping the application of PBZ or tapering down its dose after three years of its continuous application. From the results of this study, application of paclobutrazol at 5 g a.i. per tree as soil drench for three consecutive years and then its discontinuation for the subsequent three years appears to be most appropriate for 'Alphonso' mango trees in the age group of about 15 to 25 years

Effect of Pruning and Chemicals on Flowering and Fruit Yield in Mango Cv. Alphonso

A field trial was conducted from 2005 to 2009 on pruning and spray of various chemicals to study their effects on flowering and fruit yield in 'Alphonso' mango, at Indian Institute of Horticultural Research, Bangalore. Seven treatments were imposed, with pruning of fruited shoots as a common treatment, followed by chemical sprays and a control. Over the five years, flowering parameters (% vegetative, dormant or flowering shoots) were found to be non-significant among different treatments. Treatments increased fruit yield compared to control. The best treatment was T3 (Pruning+1% K2HPO4+1% KNO3 spray) which recorded mean fruit yield of 63.9 kg/plant, compared to a fruit yield of 33.0 k/ plant in control

A seventh order numerical method for singular perturbed differential-difference equations with negative shift

In this paper, a seventh order numerical method is presented for solving singularly perturbed differential-difference equations with negative shift. In recent papers the term negative shift has been used for delay. Such problems are associated with expected first exit time problem of the membrane, potential in models for neuron and in variational problems in control theory. In the numerical treatment for such type of boundary value problems, we first use Taylor approximation to tackle terms containing small shifts which converts into a singularly perturbed boundary value problem. This two point boundary value problem is transformed into general first order ordinary differential equation system. A discrete approximation of a seventh order compact difference scheme is employed for the first order system and solved by using the boundary conditions. Several numerical examples are solved and compared with exact solution. We also present least square errors, maximum errors and observed that the present method approximates the exact solution very well