Nesting Depth of Operators in Graph Database Queries: Expressiveness Vs. Evaluation Complexity

Designing query languages for graph structured data is an active field of research, where expressiveness and efficient algorithms for query evaluation are conflicting goals. To better handle dynamically changing data, recent work has been done on designing query languages that can compare values stored in the graph database, without hard coding the values in the query. The main idea is to allow variables in the query and bind the variables to values when evaluating the query. For query languages that bind variables only once, query evaluation is usually NP-complete. There are query languages that allow binding inside the scope of Kleene star operators, which can themselves be in the scope of bindings and so on. Uncontrolled nesting of binding and iteration within one another results in query evaluation being PSPACE-complete. We define a way to syntactically control the nesting depth of iterated bindings, and study how this affects expressiveness and efficiency of query evaluation. The result is an infinite, syntactically defined hierarchy of expressions. We prove that the corresponding language hierarchy is strict. Given an expression in the hierarchy, we prove that it is undecidable to check if there is a language equivalent expression at lower levels. We prove that evaluating a query based on an expression at level i can be done in $\Sigma_i$ in the polynomial time hierarchy. Satisfiability of quantified Boolean formulas can be reduced to query evaluation; we study the relationship between alternations in Boolean quantifiers and the depth of nesting of iterated bindings.Comment: Improvements from ICALP 2016 review comment

Peripheral Ossifying Fibroma

Peripheral ossifying fibroma is a relatively uncommon gingival growth that is considered to be reactive in nature and postulated to appear secondary to irritation or trauma. They usually occur in young adults with a female predominance and are solitary in nature. We report a case of peripheral ossifying fibroma in a 55-year old femal

Extended Riemann-Liouville fractional derivative operator and its applications

Many authors have introduced and investigated certain extended fractional derivative operators. The main object of this paper is to give an extension of the Riemann-Liouville fractional derivative operator with the extended Beta function given by Srivastava et al. [22] and investigate its various (potentially) useful and (presumably) new properties and formulas, for example, integral representations, Mellin transforms, generating functions, and the extended fractional derivative formulas for some familiar functions

Work-Life Balance Of Teaching Professionals

Women’s development has been considered the key to the overall development of the nation. The educated women do not want their lives to stay in the four walls of the house. They demand equal respect from their partners. Today in India with growing popula

Solvent resistant microporous/nanoporous polymeric hollow fiber and flat film membranes and their applications

The separation and purification of organic-solvent-based process streams may be carried out by membrane processes such as nanofiltration/ultrafiltration/microfiltration and membrane solvent extraction. Lack of solvent stability and chemical stability of most commercially available membranes is limiting the utilization of the above mentioned membrane technologies. This dissertation was primarily focused on developing solvent resistant hollow fiber and flat film membranes for separation and purification of organic-solvent-based process streams. Available porous polymeric supports (Polypropylene (PP), Polyethersulfone (PES) and Nylon) suitable for the required solvent-stable applications were chosen first and then the supports were modified to satisfy the requirements for the applications. Membrane modification techniques employed were interfacial polymerization (IP) and poly(ethyleneimine) (PEI) self crosslinking. Thin film composite (TFC) nanofiltration and ultrafiltration membranes were fabricated on PBS, Nylon and hydrophilized PP support membranes. Before carrying out IP, PP was hydrophilized by pre-wetting with acetone and treating with hot chromic acid solution. The introduced procedure of “modified IP” involved wetting next with the aqueous monomer solution followed by the organic monomer solution. Nanofiltration membranes were characterized using solutes, safranin 0 (MW 351) and brilliant blue R (MW 826) dyes in methanol; ultrafiltration membranes were characterized with a 70% alcoholic solution of zein (MW 35,000). These membranes were also studied for long term solvent stability in ethanol and toluene. The membrane based on PP was first hydrophilized by the techniques of “modified [P” and PHI self crosslinking. For possible applications in microfiltration of aqueous systems, these hydrophilized membranes were characterized by the water permeation rate. Crosslinking of PHI was implemented on the lumen side of the Nylon hollow fibers to reduce the pore size; then, their performance in membrane solvent back extraction was studied. Extraction of phenol from MIBK into an aqueous caustic solution was studied as a model system for reactive back extraction; extraction of acetic acid from MIBK into water was studied as a model system for nonreactive back extraction. Hollow fibers of PBS were coated on the lumen side by IP. The IP layer was again coated with silicone to make the IP coating impervious to water. The coated PES fibers were then tested for heat transfer performance. All modified membranes were also characterized using scanning electron microscopy. Thin film composite nanofiltration and ultrafiltration membranes were successfully fabricated on PP and PBS hollow fiber supports; high rejections of solutes and high solvent fluxes were achieved in UF and NT membranes. However, only the PP-based TFC membranes retained their characteristics after solvent exposure for the studied period of time. Permanent hydrophilization of PP was achieved by the “modified IP procedure. Reduced pores on the lumen side of Nylon hollow fibers provided stable aqueous-organic interface for solute transport in membrane solvent back extraction; the coating improved the extraction performance of the membranes. Better heat transfer performance was achieved in the coated PBS hollow fibers when compared with the nonporous PP hollow fibers

Prevelence and causes of visual impairment and blindness in older adults in an area of India with a high cataract surgical rate.

BACKGROUND: The cataract surgical rate (CSR) in Gujarat, India is reported to be above 10,000 per million population. This study was conducted to investigate the prevalence and causes of vision impairment/blindness among older adults in a high CSR area. METHODS: Geographically defined cluster sampling was used in randomly selecting persons >or= 50 years of age in Navsari district. Subjects in 35 study clusters were enumerated and invited for measurement of presenting and best-corrected visual acuity and an ocular examination. The principal cause was identified for eyes with presenting visual acuity < 20/32. RESULTS: A total of 5158 eligible persons were enumerated and 4738 (91.9%) examined. Prevalence of presenting visual impairment < 20/63 to 20/200 in the better eye was 29.3% (95% confidence interval [CI]: 27.5-31.2) and 13.5% (95% CI: 12.0-14.9) with best correction. The prevalence of presenting bilateral blindness (< 20/200) was 6.9% (95% CI: 5.7-8.1), and 3.1% (95% CI: 2.5-3.7) with best correction. Presenting and best-corrected blindness were both associated with older age and illiteracy; gender and rural/urban residence were not significant. Cataract in one or both eyes was the main cause of bilateral blindness (82.6%), followed by retinal disorders (8.9%). Cataract (50.3%) and refractive error (35.4%) were the main causes in eyes with vision acuity < 20/63 to 20/200, and refractive error (86.6%) in eyes with acuity < 20/32 to 20/63. CONCLUSIONS: Visual impairment and blindness is a significant problem among the elderly in Gujarat. Despite a reportedly high CSR, cataract remains the predominant cause of blindness

An Analysis of Clustering Algorithms for Big Data

Clustering is an important data mining and tool for reading big records. There are difficulties for making use of clustering strategies to huge data duo to new challenges which might be raised with massive records. As large information is relating to terabytes and peta bytes of information and clustering algorithms are come with excessive computational costs, the question is the way to take care of with this hassle and how to install clustering techniques to big information and get the outcomes in a reasonable time. This study is aimed to review the style and progress of agglomeration algorithms to cope with massive knowledge challenges from first projected algorithms until modern novel solutions. The algorithms and the centered demanding situations for generating stepped forward clustering algorithms are introduced and analyzed, and later on the viable future path for extra superior algorithms are based on computational complexity. In this paper we discuss clustering algorithms and big data applications for real world things