Diffusion of small two-dimensional Cu islands on Cu(111) studied with a kinetic Monte Carlo method

Diffusion of small two-dimensional Cu islands (containing up to 10 atoms) on Cu(111) has been studied using the newly developed self-learning Kinetic Monte Carlo (SLKMC) method which is based on a database of diffusion processes and their energetics accumulated automatically during the implementation of the SLKMC code. Results obtained from simulations in which atoms hop from one fcc hollow site to another are compared with those obtained from a parallel set of simulations in which the database is supplemented by processes revealed in complementary molecular dynamics simulations at 500K. They include processes involving the hcp (stacking-fault) sites, which facilitate concerted motion of the islands (simultaneous motion of all atoms in the island). A significant difference in the scaling of the effective diffusion barriers with island size is observed in the two cases. In particular, the presence of concerted island motion leads to an almost linear increase in the effective diffusion barrier with size, while its absence accounts for strong size-dependent oscillations and anomalous behavior for trimers and heptamers. We also identify and discuss in detail the key microscopic processes responsible for the diffusion and examine the frequencies of their occurrence, as a function of island size and substrate temperature.Peer reviewe

On The Solution of Certain Fractional Integral Equations

In this paper we introduce the linear operator of fractional integral equation of the second kind (FIESK) in the framework of the Riemann-Liouville fractional calculus. Some results concerning the existence and uniqueness have been also obtained. Particular attention is devoted to the technique of Laplace transform for treating FIESK. By applying this technique we shall derive the analytical solutions of the most linear FIESK.Other main objective concern here is to give an approximate scheme using collocation method to solve FIESK. Two fundamental questions concerning this method: its stability and convergence are discussed. We show that the analytical stability bounds are in excellent agreement with numerical tests. Comparison between exact solutions and approximate predictions is made

Retinal blood vessels extraction using probabilistic modelling

© 2014 Kaba et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.The analysis of retinal blood vessels plays an important role in detecting and treating retinal diseases. In this review, we present an automated method to segment blood vessels of fundus retinal image. The proposed method could be used to support a non-intrusive diagnosis in modern ophthalmology for early detection of retinal diseases, treatment evaluation or clinical study. This study combines the bias correction and an adaptive histogram equalisation to enhance the appearance of the blood vessels. Then the blood vessels are extracted using probabilistic modelling that is optimised by the expectation maximisation algorithm. The method is evaluated on fundus retinal images of STARE and DRIVE datasets. The experimental results are compared with some recently published methods of retinal blood vessels segmentation. The experimental results show that our method achieved the best overall performance and it is comparable to the performance of human experts.The Department of Information Systems, Computing and Mathematics, Brunel University

Microcontroller Servomotor for Maximum Effective Power Point for Solar Cell System

In this paper a Maximum Power point (MPP) tracking algorithm is developed using dual-axis servomotor feedback tracking control system. An efficient and accurate servomotor system is used to increase the system efficiency and reduces the solar cell system coast. The proposed automatic servo control system based on PIC microcontroller which is used to control the photovoltaic (PV) modules. This servo system will track the sun rays in order to get MPP during the day using direct radiation. A photo cell is used to sense the direct sun radiation and feedback a signal to the PIC microcontroller, and then the decisions are made through the microcontroller and send a command to the servomotor system to achieve maximum power generation. The proposed system is demonstrated through simulation results. Finally, using the proposed system based on PIC microcontroller, the system will be more efficient, minimum cost, and maximum power transfer is obtained

Tablets from the Sippar Library, XIII. Enuma Anu Ellil XX

The Sippar Library tablet IM 124485 is a new source for Tablet XX ofEnūma Anu Ellil (EAE), the great compilation of Babylonian celestial and meteorological omens. The twentieth tablet of the series, which deals principally with lunar eclipses on the fourteenth day of each month of the year, was edited by Francesca Rochberg in 1988 along with all the other tablets of lunar-eclipse omens inEAE(Rochberg-Halton 1988: Chapter 10). Rochberg was unable to report the whole text of her MS M = ND 4357, a Neo-Assyrian tablet from the library of the temple of Nabû at Kalaḫ; it can now be consulted asCTNIV 5 (Wiseman and Black 1996: Pls. 5–6, 145), though the copy of the reverse is inadequate. In addition a Late Babylonian exemplar of a further commentary, written in the time of Philip Arrhidaeus for the scholar Iqīša of Uruk, has come to light in W23300 (now IM 75990), published asUrukIV 162 (von Weiher 1993: 103–5, 186). Despite these additions to knowledge, some of the text ofEAEXX remained poorly enough preserved to make the discovery of a new manuscript very welcome.The new tablet allows seven sections of the text ofEAEXX to be reconstructed in full, and our understanding of the technical terminology refined as a consequence. The chief interest of this tablet ofEAEemerges more clearly than before. The common denominator of the twelve lunar-eclipse omens ofEAEXX is eclipses that, at least notionally, set in “above” and clear “below”, as observed in 1. 66 of the tablet published here. However, the observed phenomena that especially distinguish the protases ofEAEXX from those of other calendrical lunar-eclipse tablets appear to be particular to partial eclipses. The progress of the eclipse to a point at which the disk is half eclipsed (imšul) or more (eli mašāli illik) is explicitly recorded on six occasions (§§1.2, IV, V, VII, VIII, IX). The portents relate either to the moon's “emblem” (šurinnu), a term that signifies the moon in eclipse (§§1.1, IV), to its “horns” (qarnu), i.e. the cusps of the partially eclipsed disk (§§VIII, IX, X, XI, XII), or to both (§§V, VII). It seems that what the compiler ofEAEXX considered most portentous were the appearance, behaviour and other aspects of the lunar disk while the moon was half, or more than half, eclipsed.</jats:p

Tablets from the Sippar Library, VI. Atra-hasis

The Babylonian myth known to the ancients as Enūma ilū awëlum, “When the Gods Were Man”, and to modern scholarship as the Epic of Atra-ḫasīs, tells the wondrous story of the creation of mankind, of the attempts of the king of the gods, Enlil, to reduce the overpopulation that resulted from its unchecked reproduction — by plague, drought, famine and, most disastrously, the Deluge — and of the measures then taken by the gods to keep mankind's future numbers in check. Since its reconstruction some twenty-five years ago, by W. G. Lambert and A. R. Millard, there have come to light very few new sources for this composition. Several small additional fragments have been published by Lambert, and a further piece by Groneberg and Durand. The most significant discovery of new text has been the several tablets that were found in the library excavated by the late Dr Walid Al-Jadir of the University of Baghdad in the Neo-Babylonian temple of Šamaš at Sippar. This find led to a preliminary report in this journal that “there are tablets 1, 2, 3 and one other of the Standard Babylonian recension (as it must now be called) of Atra-hasis”.</jats:p

Variación en parámetros bioquímicos en un grupo de pacientes con tumor cerebral primario: revisión de cuatro estudios

Introduction: It has been well established and evidence-based fact that serum levels of proteins, cholesterol, trace elements, andpseudouridines may suffer changes during a neoplastic disease process. This report encompassed four prospective studies, original in Iraq to our knowledge, had explored the serum total proteins (TP), pseudouridines levels, total serum cholesterol (TSC), and serum trace elements (TE), in groups of patients harboring primary brain tumours (PBT) compared to healthy persons. Patients and Methods:Study number 1: A group of 107 patients, from both sexes, aged 2-75 years, harboring PBT were admitted to and operated upon via formal craniotomy by staff neurosurgeons at The Teaching Hospital at Kadhimiyah (TTHK) and Neurosurgical Hospital (NH); their sera were tested for serum total proteins (TP); the latter biochemical parameters were compared with those of 40 healthy persons. Study number II: the same patients and healthy controls were tested for pseudouridine measurement. Study number III: Another group of 30 patients with PBT were studied for TSC levels and were compared with 30 healthy volunteers. Study number IV: A third group of 26 patients with PBT, from both sexes, their sera were tested and measured for TE; the measurements were compared to 1630 volunteers from both sexes and of different age groups. The sera and brain tumor tissue samples were analysed and examined by appropriate methods at relevant laboratories of the TTHK, NH, The Medical Research Centre (MRC) of The College of Medicine, Al-Nahrain University and the Iraqi Atomic Energy Committee (IAEC). Results and Discussion: The serum TP and PBT study: Results are shown in table 1. The serum pseudouridines and PBT study: Mean levels of pseudouridine in serum of PBT patients, were significantly higher (p &lt; 0.01) than its levels in the (normal) controls, table 2. The TSC and PBT study: 1. Hesalthy persons from both sexes: age range, in years, 15 – 75, mean 40.5, SD ± 19.8; TSC range 142 – 230 mg / dl, mean 185.6 mg / dl, SD ± 24.9, (3.7 – 5.9 mmol / l, mean 4.8 mmol / l, SD± 0.6), table 3. 2. Thirty persons from both sexes having peripheral tumors, with no clinical evidence of brain tumors: age range, in years, 15 – 75, mean 54.3 ± 12.8; TSC range 90 – 220 mg / dl, 143 ± 36.3 (2.3 – 5.7 mmol / l, mean 3.7 ± 0.9), table 4. 3. Thirty patients from both sexes with primary and secondary brain tumors, age range, in years, 15 - 75, mean 41.3 ± 20.9; TSC range 140 – 284 mg / dl, 217.6 ± 41.2 (3.6 – 7.3 mmol / l, 5.6 ±1.1), table 4. Study number IV: Serum mean values (and S.D.) of all measured TEs were as follow: Se 0.045 +/- 0.011, Zn 0.320 +/- 0.095, Cu 0.607 +/- 0.154, Fe 0.880 +/- 0.456, Mg 13.625 +/- 3.994, Co 0.020 +/- 0.036, Ni 0.016 +/- 0.030, Mn 0.016 +/- 0.009, Cd 0.050 (one sample), and Cr 0.015 +/- 0.005 micrograms per milliliter (mcg / ml). All mean concentrations were consistently lower in the patients than healthy volunteers; both the Student’s (t) and probability (p value) tests were performed; for Se, Zn, Cu, Mg, Co, Ni, Mn, and Cr the p value was &lt;0.01 showing statistically significant results; however, for Fe, though the mean concentration was also lower in the brain tumor group, there was no statistical significance, p &gt; 0.05. Due to technical difficulties and very low concentration of Cd, it was not measured in healthy volunteers; however, it was measured in only one patient’s serum sample; this has been discarded from the study, table 5. Conclusions: Levels of serum TP, TC, and pseudouridine are higher in patients with PBT than in healthy people; however, those of serum TE are lower in the PBT group than healthy persons; the results of this report are in keeping with those of other researchers. The biochemical parameters can be an additional laboratory monitor in the investigation of PBT patients; however, both the specificity and sensitivity need to be ascertained. To our knowledge, this was the first study to be performed in Iraq in the setting of PB