Theory and Implementation of a Variational Database Management System

In this thesis, I present the variational database management system, a formal framework and its implementation for representing variation in relational databases and managing variational information needs. A variational database is intended to support any kind of variation in a database. Specific kinds of variation in databases have already been studied and are well-supported, for example, schema evolution systems address the variation of a database’s schema over time and data integration systems address variation caused by accessing data from multiple data sources simultaneously. However, many other kinds of variation in databases arise in practice, and different kinds of variation often interact, but these scenarios are not well-supported by the existing work. For example, neither the schema evolution systems nor the database integration systems can address variation that arises when data sources combined in one database evolve over time. This thesis collects a large amount of work: It defines the variational database framework and the syntax and denotational semantics of the variational relational algebra, a query language for variational databases. It presents two use cases of the variational database framework that are based on existing datasets and scenarios that are partially supported by existing techniques. It presents the variational database management system which is a prototype of variational databases and variational relational algebra as an abstract layer written in Haskell on top of a traditional RDBMS. It also presents several theoretical results related to the framework and the query language, such as syntax-based equivalence rules that preserve the semantics of a query, a type system for ensuring that a variational query is well-formed with respect to the underlying variational schema, and a confluence property of the variational relational algebra type system with respect to the relational algebra type system and its denotational semantics

Feeding habits of yellowfin seabream (Acanthopagrus latus) in the northern region of the Persian Gulf

Feeding habits of yellowfin seabream (Acanthopagrus latus) was investigated in coastal waters of the Northern Persian Gulf. This investigation was conducted by monthly sampling of thirty fish from September 2011 through August 2012. Fish size ranged from 17.98 ± 2.07 to 32.31 ± 6.52 cm in total length and from 134.01 ± 45.62 to 720.46 ± 292.58 g in weight. The highest value of gastro-somatic index was obtained in September (5.22 ± 0.04) and the lowest in December (1.61 ± 0.03) with annual average of 2.50 ± 0.60. The result of gastro-somatic index revealed that the highest feeding activity of A. latus was during autumn. The highest level of vacuity index was observed in summer (34.95 ± 4.71) and the lowest in autumn (25.88 ± 2.71) indicating that the highest number of empty stomachs was in summer. Annual average of vacuity index was 30.14 ± 5.72 exhibiting that A. latus was comparatively gluttonous in the Northern Persian Gulf. Bivalves and shrimps were the major food items found in the stomach of A. latus showing food preference indices of 45.86% and 30.67%, respectively. Other food items included crabs (12.66%), aquatic plants (4.05%), animal derivatives (4.52%) and gastropods (2.23%). According to the results, animal derivatives, aquatic plants and gastropods were eaten accidentally and were not the food items of A. latus in coastal waters of Hormozgan. The average relative length of gut was 1.41 ± 0.15 showing that A. latus was omnivorous in this region

Topological and geometrical disorder correlate robustly in two-dimensional foams

A 2D foam can be characterised by its distribution of bubble areas, and of number of sides. Both distributions have an average and a width (standard deviation). There are therefore at least two very different ways to characterise the disorder. The former is a geometrical measurement, while the latter is purely topological. We discuss the common points and differences between both quantities. We measure them in a foam which is sheared, so that bubbles move past each other and the foam is "shuffled" (a notion we discuss). Both quantities are strongly correlated; in this case (only) it thus becomes sufficient to use either one or the other to characterize the foam disorder. We suggest applications to the analysis of other systems, including biological tissues

Antiviral effects of Lactobacillus crispatus against HSV-2 in mammalian cell lines

Background: Herpes simplex virus type 2 (HSV-2) infectious disease is one of the most common viral sexually transmitted diseases. As regards, vaginal lactobacilli play an important role in protecting host against the urogenital pathogens; here we assessed the potential antiviral activity of Lactobacillus crispatus against HSV-2 infection in vitro. Methods: Both Vero and HeLa cell lines were treated by L. crispatus before, during and after HSV-2 infection. The pre-incubation assay was also performed for the evaluating of virus adsorption by L. crispatus. Virus titer reduction in each stage was determined by a plaque reduction assay. Results: L. crispatus significantly decreased the infectivity of the HSV-2 in initial steps on both cell lines; however, no significant inhibition was ascertained during adsorption and multiplication process. The lactobacilli adhere on Vero cells two-fold stronger than HeLa and subsequently protect the Vero cells nearly 2.5 fold higher than HeLa cell against the virion. Co-incubation of HSV-2 with bacterial cells prior to virus inoculation significantly decreased the virus titer. Conclusion: L. crispatus appears to inhibit the entry of the virus into cells by trapping HSV-2 particles. In addition, formation of L. crispatus microcolonies in the cell surface could block HSV-2 receptors and prevent viral entry to cells in initial infection steps. © 201

Electronic and optical properties of doped TiO2 by many-body perturbation theory

Doping is one of the most common strategies for improving the photocatalytic and solar energy conversion properties of TiO2, hence an accurate theoretical description of the electronic and optical properties of doped TiO2 is of both scientific and practical interest. In this work we use many-body perturbation theory techniques to investigate two typical n-type dopants, niobium and hydrogen, in TiO2 rutile. Using the GW approximation to determine band edges and defect energy levels, and the Bethe-Salpeter equation for the calculation of the absorption spectra, we find that the defect energy levels form nondispersive bands lying 3c2.2 eV above the top of the corresponding valence bands ( 3c0.9 eV below the conduction bands of the pristine material). The defect states are also responsible for the appearance of low-energy absorption peaks that enhance the solar spectrum absorption of rutile. The spatial distributions of the excitonic wave functions associated with these low-energy excitations are very different for the two dopants, suggesting a larger mobility of photoexcited electrons in Nb-TiO2

Pseudogap phase of cuprate superconductors confined by Fermi surface topology

The properties of cuprate high-temperature superconductors are largely shaped by competing phases whose nature is often a mystery. Chiefly among them is the pseudogap phase, which sets in at a doping $p^*$ that is material-dependent. What determines $p^*$ is currently an open question. Here we show that the pseudogap cannot open on an electron-like Fermi surface, and can only exist below the doping $p_{FS}$ at which the large Fermi surface goes from hole-like to electron-like, so that $p^*$ $\leq$ $p_{FS}$. We derive this result from high-magnetic-field transport measurements in La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ under pressure, which reveal a large and unexpected shift of $p^*$ with pressure, driven by a corresponding shift in $p_{FS}$. This necessary condition for pseudogap formation, imposed by details of the Fermi surface, is a strong constraint for theories of the pseudogap phase. Our finding that $p^*$ can be tuned with a modest pressure opens a new route for experimental studies of the pseudogap.Comment: 15 pages, 5 figures, 7 supplemental figure

Sandwich structure polymer electrolyte membranes containing phosphotungstic acid immobilized electospun nanofibers

The advances in proton exchange membranes (PEM)s is critical for improving the performance of fuel cells [1]. Membranes compromising perfluorosulfonic acid polymers such as Nafion have been used extensively due to their desired conductivity and stability. However, these materials need to be saturated with water to obtain practical level of proton conductivity. There is a strong demand for the PEMs to work at lower relative humidity or under anhydrous conditions because the electrochemical reactions will be accelerated and water management of fuel cell will be simpler. Various designing strategies and advanced materials have been developed to mitigate for this issue without causing serious loss in proton conductivity or stability [2]. Among all, the introducing of inorganic proton conductors such as heteropoly acids have been considered widely. Generally, HPAs (such as phosphotungstic acid H3PW12O40, PWA) have a very strong Brønsted acidity approaching the superacid region (more acidic than Nafion) [3]. In this work, high level of PWA was self-anchored onto nylon electrospun nanofiberous sheet (Figure 1b). Sandwich structured proton conducting membranes were fabricate by assembling nanofibrous central layer with outer Nafion layers (Figure 1b). Since the PWA is attached to the polymer backbones, the risk of leaching out is minimized. Moreover, the significant synthetic versatility of the method helps to increase PWA immobilization level. As shown in the Figure 1c, proton conductivity of as high as 60 mS cm-1 at 30 °C was achieved which is comparable with Nafion 115. The durability of the proton conductivity of sandwiched membrane

High frequency of bipolar disorder comorbidity in medical inpatients

Objective: Bipolar disorder is a severe, disabling, and recurring disorder. Some studies have shown that the frequency of bipolar disorder in patients with medical diseases is higher than healthy controls. The aim of this study was to investigate the frequency of bipolar disorders in medically ill patients hospitalized in Iranian general hospitals. Method: In this cross sectional study, 697 inpatients (342 men, 49.1) from different wards of 3 general hospitals, with the mean age of 39.3+-10, were enrolled in the study using nonprobability sampling. Demographic questionnaire, Mood Disorder Questionnaire (MDQ) and Bipolar Spectrum Diagnostic Scale (BSDS) were used. Inclusion criteria were as follow: informed consent, age 18-65 years, ability to speak Persian, and having at least middle school education. Results: The frequency of bipolar disorder was 12.1 and 20.8 based on BSDS and MDQ, respectively. The results of both tests were positive in 7.9 of hospitalized patients. The frequency of bipolar mood disorder was significantly higher in single patients and in those with comorbidity of alcohol and substance use disorders. Conclusion: Considering the high frequency of bipolar mood disorders in hospitalized medically ill patients and its probable effects on compliance and prognosis, early screening, diagnosis, and treatment of bipolar mood disorders is important in these patients. © 2019 Tehran University of Medical Sciences. All rights reserved

Wiedemann-Franz law and abrupt change in conductivity across the pseudogap critical point of a cuprate superconductor

The thermal conductivity $\kappa$ of the cuprate superconductor La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ was measured down to 50 mK in seven crystals with doping from $p=0.12$ to $p=0.24$, both in the superconducting state and in the magnetic field-induced normal state. We obtain the electronic residual linear term $\kappa_0/T$ as $T \to 0$ across the pseudogap critical point $p^{\star}= 0.23$. In the normal state, we observe an abrupt drop in $\kappa_0/T$ upon crossing below $p^{\star}$, consistent with a drop in carrier density $n$ from $1 + p$ to $p$, the signature of the pseudogap phase inferred from the Hall coefficient. A similar drop in $\kappa_0/T$ is observed at $H=0$, showing that the pseudogap critical point and its signatures are unaffected by the magnetic field. In the normal state, the Wiedemann-Franz law, $\kappa_0/T=L_0/\rho(0)$, is obeyed at all dopings, including at the critical point where the electrical resistivity $\rho(T)$ is $T$-linear down to $T \to 0$. We conclude that the non-superconducting ground state of the pseudogap phase at $T=0$ is a metal whose fermionic excitations carry heat and charge as conventional electrons do.Comment: 10 pages, including Supplementary Materia