DEFINING TOPIC BOUNDARIES IN SEARCH ENGINE TRANSACTION LOGS USING GENETIC ALGORITHMS

This study proposes to use genetic algorithms for defining the topic boundaries in search of engine transaction logs. Users are interested in multiple topics during a search session, and genetic algorithms are used in this study to determine whether a search engine user has changed topics during a session. Sample data logs from FAST and Excite search engines were analyzed. The findings show that genetic algorithms are fairly successful in identifying topic continuations and shifts in search engine transaction logs.     

Performance of joint multilevel/AES‐LDPCC‐CPFSK schemes over wireless sensor networks

In wireless sensor networks, data encryption and channel coding are considered together for ensuring secure and robust communication. In order to achieve this purpose, we introduce a new joint scheme, namely ‘Multilevel/Advanced Encryption Standard‐Low Density Parity Check Coded‐Continuous Phase Frequency Shift Keying (ML/AES‐LDPCC‐CPFSK)’. AES algorithm is the most powerful and widely used symmetric key cryptography in providing secure data transmission. LDPC codes have very large Euclidean distance and use iterative decoding algorithms. In this study, we have increased error performance employing multilevel structure to AES and LDPC. In all communications systems, phase discontinuities of modulated signals result in extra bandwidth requirements. CPFSK, which is a special type of continuous phase modulation, is a powerful solution for this problem. In this paper, we simulate error performance of ML/AES‐LDPCC‐CPFSK for regular LDPC codes. Simulation results are drawn for 4CPFSK, 8CPFSK and 16CPFSK over wireless cooperative sensor networks. Using this scheme, we are able to improve bit error performance, channel throughput, security level of communication and reduction in complexity compared with related schemes such as various turbo code structures. Copyright © 2009 John Wiley & Sons, Ltd.     

Spectrophotometric and electrochemical behavior of a novel azocalix[4]arene derivative as a highly selective chromogenic chemosensor for Cr

In this study, a novel azocalix[4]arene derivative, 5,11,17-tris[(1-naphtyl)azo]-25,26,27,28-tetrahydroxy-calix[4]arene (NAC4) bearing napthyl groups on the upper rim was synthesized. Its complexation behavior for alkali, alkaline-earth and various heavy metal ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Pb²⁺, Hg²⁺, Ni²⁺, Cd²⁺, Cu²⁺, Zn²⁺, Co²⁺, Fe²⁺, Cr³⁺, Ag⁺) was investigated by spectroscopic and voltammetric methods. This chemosensor exhibits decreased absorbance in the presence of Hg²⁺ and a unique absorbance quenching effect only for Cr³⁺. In addition, a new absorption band centered at 565 nm with the formation of the 1:1 host–guest complex (Cr³⁺-NAC4) was observed in the case of Cr³⁺, leading to an obvious color change from light orange to dark lilac. In voltammetric experiments, Cr³⁺ ions decreased voltammetric peaks of NAC4, whereas no significant changes occurred in the presence of the other metal ions. The Benesi–Hildebrand method was used to determine a logarithmic value of 3.76 for the association constant of the complex between Cr³⁺ and NAC4.     

Controlled Distribution of Solid Catalysts into Two Immiscible Liquid Phases – Synthesis and Catalytic Applications

Photometathesis of C₃H₆ proceeded on the sprayed MoO₃ catalyst under UV irradiation with wavelength <290 nm. The photoactivity on the spray catalyst was 20-fold higher than that on the commercial MoO₃. The X-ray diffraction (XRD) results showed the anisotropic growth of the crystal in the spray catalyst. The edge-rich structure was formed in the bulk molybdenum oxide by spray reaction technique.     

Hydrogen-bonded diketopyrrolopyrrole (DPP) pigments as organic semiconductors

Diketopyrrolopyrroles (DPPs) have recently gained attention as building-blocks for organic semiconducting polymers and small molecules, however the semiconducting properties of their hydrogen-bonded (H-bonded) pigment forms have not been explored. Herein we report on the performance of three archetypical H-bonded DPP pigments, which show ambipolar carrier mobilities in the range 0.01–0.06 cm²/V s in organic field-effect transistors. Their semiconducting properties are correlated with crystal structure, where an H-bonded crystal lattice supports close and relatively cofacial π–π stacking. To better understand transport in these systems, density functional theory calculations were carried out, indicating theoretical maximum ambipolar mobility values of ∼0.3 cm²/V s. Based on these experimental and theoretical results, H-bonded DPPs represent a viable alternative to more established DPP-containing polymers and small molecules where H-bonding is blocked by N-alkylation.     

Regional epidemiological features of lip, oral cavity, and oropharyngeal cancer

Lip, oral cavity, and oropharyngeal cancer are among the most common forms of the disease in the world. These types of cancer display significant geographic, ethnic, and socioeconomic variations. We examined the cases of cancer of the lip, oral cavity, and oropharynx diagnosed in the Department of Otolaryngology at the University of Uluda? School of Medicine during the last 5 years, July 1990 to June 1995, and recorded the epidemiological features of these tumors. The Department of Otolaryngology treated a total of 26,225 in- and outpatients during the 5-year period. 320 of these patients (1.2%) were seen for head and neck cancer. 42 of the 320 patients (13.1%) were diagnosed with cancer of the lip, oral cavity, and oropharrynx. After the larynx, this was the second most frequent location of malignant head and neck tumors. We discovered the following epidemiological and pathological features: (1) The incident rate was highest in patients between 41 and 60 years of age. (2) 70% of the patients were male, and 76% of them had a history of tobacco/alcohol use. (3) Occupation had no apparent relevance (four of the patients were farmers). (4) Approximately one third of the patients had undergone medical therapy prior to diagnosis. (5) One third of the patients had initially seen a dentist for treatment, and approximately half had poor dental and oral hygiene. (6) The most frequent symptom was ulceration. (7) Histopathological examination revealed squamous cell carcinoma in 88% of the cases. (8) The cancer was localized to the lip in 31% of cases, oral cavity, 50%, and oropharynx, 19%. (9) Almost half of the cancer cases were diagnosed in advanced stage (stages III and IV).     

Infantile spasms as the initial symptom of biotinidase deficiency

Two patients with biotinidase deficiency had diagnoses of infantile spasms made at 1 month of age. Biotinidase deficiency may be seen early in the neonatal period without the characteristic findings such as alopecia and seborrheic dermatitis. This diagnosis should be considered in patients with infantile spasms.     

Pregnancy after transfer of embryos which were generated from in-vitro matured oocytes

In-vitro maturation of human oocytes is an important technique in assisted reproduction due to its potential for reducing the use of fertility drugs. We offered this technique as an alternative to cancelling the cycle to a patient who was at risk of ovarian hyperstimulation syndrome (OHSS) after treatment with gonadotrophin-releasing hormone analogue (GnRHa) and human menopausal gonadotrophin (HMG). The patient had 40 visible antral follicles with a maximum diameter of 13 mm and an oestradiol concentration of 14,000 pmol/l on cycle day 12. Immature oocytes were aspirated transvaginally under ultrasound guidance. Ten cumulus-enclosed oocytes were harvested and nine of them completed nuclear maturation to metaphase II after 48 h in culture. By 18 h after an intracytoplasmic sperm injection (ICSI) procedure, seven of these metaphase II stage oocytes displayed two distinct pronuclei and two polar bodies. All fertilized oocytes but one underwent cleaveage; four of these were transferred 2 days later. Endometrial priming was initiated with 8 mg oestradiol valerate daily from the day of oocyte retrieval and 50 mg progesterone was injected i.m. daily starting 2 days after that. A single intrauterine sac was seen containing one fetus with positive fetal heart beat on ultrasound at 7 weeks of gestation. Unfortunately, the pregnancy ended at 24 weeks shortly after premature rupture of membranes; a live healthy-looking girl was delivered who died 18 days later.     

Effects of composition, texture and diagenesis on porosity, permeability and oil recovery in a sandstone reservoir

Relationship among depositional texture, composition, diagenesis, porosity, permeability, initial water saturations and residual oil saturations have been investigated in a set of sandstone samples from a North American oil reservor. Pointcount, compositional and textural data obtained from thin sections were used.Grain size, sorting and mineralogy are closely interrelated. As grain size increases, sorting decreases and the proportion of readily soluble detrial grains increases.The type and extent of diagenetic alteration is related to grain size. Silica cement as overgrowths is more common in finer-grained sandstones with abundant monocrystalline quartz, whereas carbonate cement is more common in coarsergrained sandstones. Carbonate dissolution is extensive in some intervals in the reservoir.Sandstone samples were subdivided into tow subgroups in which relationshiops among grain size, porosity and permeability are significantly different: Sandstones with less than 13% porosity are strongly influenced by carbonate cement which controls porosity and permeability, independently of variations of grain size and sorting. Sandstones having porosity greater than 13% have undergone extensive carbonate dissolution, and coarse-grained sandstones have more secondary porosity than the finer-grained due to dissolution of unstable constituents. Both porosity and permeability are positively correlated with grain size in these samples.Initial (connate) water saturation increases with grain size because of the strong correlation between increasing grain size and polycrystalline grains which have intra-grain microporosity. Increasing heterogeneity with increasing grain size is thought to contribute to higher residual oil saturations in coarser-grained, more poorly sorted sandstones. A decrease in oil recovery efficiency with increasing grain size and permeability may be predicted for other sandstone reservoir rocks deposited in similar types of environments.