The backward crosstalk effect or response grouping in the psychological refractory period paradigm

Background: In the psychological refractory period paradigm, the second response time is increased as the interval between the first and second stimulus is decreased. The response delay for the second stimulus is called the psychological refractory period. In contrast with these findings, some evidence of the backward crosstalk effect has shown that the first reaction time is affected by the second stimulus. The capacity sharing models, in which multiple stimuli can be processed simultaneously, unlike central bottleneck models, are able to provide some explanations for the changes in the reaction time to the first stimulus. However, sometimes these changes could be arisen from response grouping; the first response remains on the processing buffer until the response to the second stimulus is prepared, then both stimuli are responded simultaneously. The questions of this study were whether the second task difficulty and time interval manipulation would affect the first task response or not and in what extend changes are because of response grouping? Materials and Methods: Detection, discrimination and choice tasks were used as the second task in the psychological refractory period paradigm and the time interval between stimuli was 50, 100, 200, 400, or 1000 ms. Results: The type of the second stimulus and time interval between stimuli had an effect on the second-task and first-task reaction times. Conclusion: In the detection group, the first task response time changes were consistent with grouping between the two responses, but in the discrimination group the changes would arise from capacity limitation and were consistent with the backward crosstalk effect

Gaussian mixture model-based contrast enhancement

In this study, a method for enhancing low-contrast images is proposed. This method, called Gaussian mixture model-based contrast enhancement (GMMCE), brings into play the Gaussian mixture modelling of histograms to model the content of the images. On the basis of the fact that each homogeneous area in natural images has a Gaussian-shaped histogram, it decomposes the narrow histogram of low-contrast images into a set of scaled and shifted Gaussians. The individual histograms are then stretched by increasing their variance parameters, and are diffused on the entire histogram by scattering their mean parameters, to build a broad version of the histogram. The number of Gaussians as well as their parameters are optimised to set up a Gaussian mixture modelling with lowest approximation error and highest similarity to the original histogram. Compared with the existing histogram-based methods, the experimental results show that the quality of GMMCE enhanced pictures are mostly consistent and outperform other benchmark methods. Additionally, the computational complexity analysis shows that GMMCE is a low-complexity method

Comparison of biological factors of Aphanius sophiae in Cheshmeh-Ali of Damghan and Shour River of Eshtehard

Length, age frequency, von Bertalanfi growth parameter, reproduction and absolute fecundity of two populations of killifish (Aphanius sophiae) from Cheshmeh-Ali of Damghan and Shour River of Eshtehard were studied monthly from October 2004 to November 2005. There was no significant difference between sex ratios of the two populations (X^2.0.679, P=0.410). Age and length frequencies revealed that female fish of Cheshmeh-Ali were taller and longer-lived than those of Shour River. Maximum of gonadosomatic index of Cheshmeh-Ali fish was in May while in the case of Shour River, it was, in April. The absolute fecundity showed no significant difference using ANCOVA whereas egg diameter of Cheshmeh-Ali population was significantly bigger than Shour River population (P<0.001)

Analysis of mitochondrial DNA sequences of Turcinoemacheilus genus (Nemacheilidae Cypriniformes) in Iran

Members of Nemacheilidae Family, Turcinoemacheilus genus were subjected to molecular phylogenetic analysis in this study. This genus was reported in 2009 to inhabit in Karoon River drainage, in contrary to previous assumption that it was the endemic species in the Basin of Tigris River. It was sampled from three stations placed in different tributaries in Karoon drainage and evaluated to understand the molecular phylogenetic relationships of Turcinoemacheilus in Iran. The mitochondrial cytochrome b gene (cyt b) and control region were used to infer phylogenetic relationships. PCR amplification of control region was not carried out successfully, possibly due to the high divergence of this sequence in the studied genus. The amplified fragments of cyt b were sequenced then analyzed by the use of phylogenetic software. Only one divergent position was seen in all three samples stations located in amino acid position 365. GTR and p-distances of cytochrome b gene for T. kosswigi computed from different stations of running water in Karoon drainage showed these samples belong to different populations and fall in intraspecific differences. In this study, examination of the molecular phylogeny using Bayesian analysis, maximum parsimony or neighbor-joining define the phylogentics of Turcinoemacheilus genus as a monophyletic clade which is sister-clade of Nemacheilus and Schistura genera. This report is the first report of Turcinoemacheilus molecular data and could describe molecular phylogeny of this genus in loaches

Morphometric and meristic study of Garra rufa populations in Tigris and Persian Gulf Basins

This study was conducted to determine morphometric and meristic characteristics of Garra rufa in 13 stations of Tigris and Persian Gulf basins. We caught 310 specimens during the year 2007-2008 using electro-shocker and sachok. Univariate analysis of variance (ANOVA) and principal component analysis were conducted and the ANOVA revealed significant differences in 28 morphometric and 9 meristic factors (P<0.05). Factor analysis showed that G. rufa of thirteen stations had 48.855% changes in 3 factors of the first morphometric characters (pectoral fin length, ventral fin length, depth of anal fin) and 71/611% changes in 3 factors of the first meristic characters (lateral line scales , circum peduncle scales, predorsal scales). Plotting the first and second principal component morphometric and meristic characters showed that the Mond River population was separated from the others but the other populations were overlapping with each other in the characteristics studied

Effect of human chorionic gonadotropin on sexual maturation, sex steroids and thyroid hormone levels in Caspian lamprey (Caspiomyzon wagneri Kessler, 1870)

The objective of this study was to determine the effect of human chorionic gonadotropin (hCG) on sexual maturation, plasma sex steroids [17β-estradiol, (E2) and 17α-hydroxy progesterone (17α_OHP)] and thyroid hormones (triiodothyronine, T3 and thyroxin, T4) levels in upstream - migrating Caspian lamprey. During the experiment, 36 fish (24 females and 12 males) in spring 2013 and 36 fish (24 females and 12 males) in fall 2013 were collected from the Shirud River estuary in Mazandaran Province, the Southern Caspian Sea during their upstream migration to the freshwater. All fish were injected with hCG at the doses of 1000, 1500 and 2000 IU.kg BW-1. The injection was a two - step process (50% of hormone in each step) by 12 h interval. After the first injection, fish were retained in the cages in the river beds and 24 hours after the second injection, fish were checked for egg and sperm release after mild abdomen pressure. Blood samples were taken for determining sex steroid levels. Results showed that hCG hormone injections caused increase in migration of germinal vesicle in the oocyte of female and sperm release in males. Significant differences were found in the serum E2 and 17α-OHP levels in hCG - injected fish compared to the control. However, no significant differences were found in serum T3 and T4 levels in the hCG -injected fish. According to the results, the appropriate hCG dosage to induce the reproduction acceleration in Caspian lamprey is 1500-2000 IU.kg BW-1

Hydrology and hydrobiology of Chaloos River

The Chaloos River originates from Alborz Mountain and enters into the Caspian Sea in Chaloos city. Five stations were chosen in different areas for the study during 1371 to 1372 (1992-93). Total variation range of hardness decreased 1 to 5 station, but measure NH4 and NO3 increased. 45 genera belongs to 4 phyla of phytoplankton as follows: Chrysophyta, Chlorophyta, Euglenophyta and Cyanophyta. Zooplankton existing in this river belong to animal classes, which had more abundance in Sarcodina and Monogononta. The benthos river establish Insecta larvae of Ephemeroptera, Coleoptera, Diptera, Plecoptera and Odonata (Orders). Chaloos fishes included to 4 families, 10 genera and 12 species. Cyprinidac consisted 66.7% of total fish and had maximum diversity at the various stations

Biotechnological production of taxanes: a molecular approach

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/46988Plant cell cultures constitute a promise for the production of a high number of phytochemicals, although the majority of bioprocesses that have been developed so far have not resulted commercially successful. An overview indicates that most of the research carried out until now is of the empirical type. For this reason, there is a need for a rational approach to the molecular and cellular basis of metabolic pathways and their regulation in order to stimulate future advances. The empirical investigations are based on the optimization of the culture system, exclusively considering input factors such as the selection of cellular lines, type and parameters of culture, bioreactor design and elicitor addition, and output factors such as cellular growth, the uptake system of nutrients, production and yield. In a rational approach towards the elucidation of taxol and related taxane production, our group has studied the relationship between the taxane profile and production and the expression of genes codifying for enzymes that participate in early, intermediate and late steps of their biosynthesis in elicited Taxus spp cell cultures. Our results show that elicitors induce a dramatic reprogramming of gene expression in Taxus cell cultures, which likely accounts for the enhanced production of taxol and related taxanes and we have also determined some genes that control the main flux limiting steps. The application of metabolic engineering techniques for the production of taxol and taxanes of interest is also discussed

Identification and differentiation of Fasciola hepatica and Fasciola gigantica using a simple PCR-restriction enzyme method

Accurate morphological differentiation between the liver fluke species Fasciola hepatica and Fasciola gigantica is difficult. We evaluated PCR-restriction enzyme profiles of internal transcribed spacer 1 (ITS1) that could aid in their identification. Fifty F. hepatica and 30 F. gigantica specimens were collected from different hosts in three provinces of Iran. For DNA extraction, we crushed fragments of the worms between two glass slides as a new method to break down the cells. DNA from the crushed materials was then extracted with a conventional phenol-chloroform method and with the newly developed technique, commercial FTA cards. A primer pair was selected to amplify a 463-bp region of the ITS1 sequence. After sequencing 14 samples and in silico analysis, cutting sites of all known enzymes were predicted and TasI was selected as the enzyme that yielded the most informative profile. Crushing produced enough DNA for PCR amplification with both the phenol-chloroform and commercial FTA card method. The DNA extracted from all samples was successfully amplified and yielded a single sharp band of the expected size. Digestion of PCR products with TasI allowed us to distinguish the two species. In all samples, molecular identification was consistent with morphological identification. Our PCR-restriction enzyme profile is a simple, rapid and reliable method for differentiating F. hepatica and F. gigantica, and can be used for diagnostic and epidemiological purposes. © 2009 Elsevier Inc. All rights reserved

Is Medical Research Informing Professional Practice More Highly Cited? Evidence from AHFS DI Essentials in Drugs.com

This is an accepted manuscript of an article published by Springer in Scientometrics on 21/02/2017, available online: https://doi.org/10.1007/s11192-017-2292-3 The accepted version of the publication may differ from the final published version.Citation-based indicators are often used to help evaluate the impact of published medical studies, even though the research has the ultimate goal of improving human wellbeing. One direct way of influencing health outcomes is by guiding physicians and other medical professionals about which drugs to prescribe. A high profile source of this guidance is the AHFS DI Essentials product of the American Society of Health-System Pharmacists, which gives systematic information for drug prescribers. AHFS DI Essentials documents, which are also indexed by Drugs.com, include references to academic studies and the referenced work is therefore helping patients by guiding drug prescribing. This article extracts AHFS DI Essentials documents from Drugs.com and assesses whether articles referenced in these information sheets have their value recognised by higher Scopus citation counts. A comparison of mean log-transformed citation counts between articles that are and are not referenced in AHFS DI Essentials shows that AHFS DI Essentials references are more highly cited than average for the publishing journal. This suggests that medical research influencing drug prescribing is more cited than average