Irradiation effects in oxide glasses doped with transition and rare-earth elements

International audienceThe effect of -irradiation on silicate and aluminoborosilicate glasses doped with transition metals (TM) and rare earth (RE) elements has been studied using Electron Paramagnetic Resonance (EPR), Raman and luminescence spectroscopy. Irradiation leads to the reduction of both Cr and Mn ions in both types of glass matrix. It is shown that even small amounts of TM dopants completely block defect production, as occurs under irradiation in non-doped glasses. As well, TM doping results in the disappearance of structural changes in the glass (densification, polymerization increase and Na migration) for doses of ~ 10 Gy. Unlike TM-doped matrices, incorporation of RE ions into aluminoborosilicate glass blocks neither defect production nor structural changes in glass matrices during irradiation. Simultaneously, we observe a reduction of RE ions, most clearly demonstrated for Ce ions in aluminoborosilicate glasses. We propose that the relative stability of the different charge states of the RE ions is linked to the efficiency of the reduction process, and therefore to the evolution of the glass structure during irradiation

Investigating the prevalence and causes of prescribing errors in general practice : the PRACtICe Study

Report prepared by the University of Nottingham, University of Reading and University of Hertfordshir

Quaternary coastal uplift along the Talara Arc (Ecuador, Northern Peru) from new marine terrace data

Marine Geology, v. 228, n. 1-4, p. 73-91, 2006. http://dx.doi.org/10.1016/j.margeo.2006.01.004International audienceMarine terrace sequences have been investigated along the Talara Arc, a 1000-km-long stretch of the coast of Ecuador and northern Peru, characterized by subduction with a concave plan-view. Seven areas were investigated, evidencing flights of up to seven marine terraces with elevations reaching up to 360 m above mean sea level (amsl). Dating of the terraces was made using the Infra Red Stimulated Luminescence (IRSL) technique on sands as old as MIS 9 (∼330 ka). 14 C and U-series dates were obtained from fossil shells for geochronological cross control. Mean uplift rates along the Talara Arc range from about 0.10 up to 0.50 mm/ yr. The strongest uplift is observed in the Manta Peninsula of Ecuador in front of the subduction of the Carnegie Ridge. The uplift rate tends to slow down towards the northern and southern ends of the Talara Arc and then the transition toward the stable or subsiding coasts of central Peru and northern Ecuador and Colombia is sharp. The uplift appears to be homogeneous and related to 1) the map view curvature of the Arc, 2) the concave subduction pattern and 3) the Carnegie Ridge subduction

Krüppel-like factor 5 is a crucial mediator of intestinal tumorigenesis in mice harboring combined ApcMin and KRASV12 mutations

<p>Abstract</p> <p>Background</p> <p>Both mutational inactivation of the adenomatous polyposis coli (<it>APC</it>) tumor suppressor gene and activation of the <it>KRAS </it>oncogene are implicated in the pathogenesis of colorectal cancer. Mice harboring a germline <it>Apc</it>^{<it>Min </it>}mutation or intestine-specific expression of the <it>KRAS</it>^<it>V</it>12gene have been developed. Both mouse strains develop spontaneous intestinal tumors, including adenoma and carcinoma, though at a different age. The zinc finger transcription factor Krüppel-like factor 5 (KLF5) has previously been shown to promote proliferation of intestinal epithelial cells and modulate intestinal tumorigenesis. Here we investigated the <it>in vivo </it>effect of <it>Klf5 </it>heterozygosity on the propensity of <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12double transgenic mice to develop intestinal tumors.</p> <p>Results</p> <p>At 12 weeks of age, <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12mice had three times as many intestinal tumors as <it>Apc</it>^{<it>Min </it>}mice. This increase in tumor number was reduced by 92% in triple transgenic <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice. The reduction in tumor number in <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice was also statistically significant compared to <it>Apc</it>^{<it>Min </it>}mice alone, with a 75% decrease. Compared with <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12, tumors from both <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-and <it>Apc</it>^{<it>Min </it>}mice were smaller. In addition, tumors from <it>Apc</it>^{<it>Min </it>}mice were more distally distributed in the intestine as contrasted by the more proximal distribution in <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12and <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice. Klf5 levels in the normal-appearing intestinal mucosa were higher in both <it>Apc</it>^{<it>Min </it>}and <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12mice but were attenuated in <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice. The levels of β-catenin, cyclin D1 and Ki-67 were also reduced in the normal-appearing intestinal mucosa of <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice when compared to <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12mice. Levels of pMek and pErk1/2 were elevated in the normal-appearing mucosa of <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12mice and modestly reduced in Apc^Min/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice. Tumor tissues displayed higher levels of both Klf5 and β-catenin, irrespective of the mouse genotype from which tumors were derived.</p> <p>Conclusions</p> <p>Results of the current study confirm the cumulative effect of <it>Apc </it>loss and oncogenic <it>KRAS </it>activation on intestinal tumorigenesis. The drastic reduction in tumor number and size due to <it>Klf5 </it>heterozygosity in <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12mice indicate a critical function of KLF5 in modulating intestinal tumor initiation and progression.</p

Load Balancing Objective Function in RPL draft-qasem-roll-rpl-load-balancing-00

This document proposes an extended Objective Function(OF) that balances the number of children nodes of the parent nodes to avoid the overloading problem and ensure node lifetime maximization in the IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL). The standard OFs are used to build a Destination Oriented Directed Acyclic Graph (DODAG) where the bottleneck nodes may suffer from unbalanced traffic load. As a result, a part of the network may be disconnected as the energy of the overloaded preferred parent node will drain much faster than other candidate parents. Thus, a new RPL metric has been introduced to balance the traffic load over the network. The potential extra overhead has been mitigated using a new utilization technique. Finally, the proposed OF amends the DODAG Information Object (DIO) message format. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79

An efficient intrusion detection model based on hybridization of artificial bee colony and dragonfly algorithms for training multilayer perceptrons

One of the most persistent challenges concerning network security is to build a model capable of detecting intrusions in network systems. The issue has been extensively addressed in uncountable researches and using various techniques, of which a commonly used technique is that based on detecting intrusions in contrast to normal network traffic and the classification of network packets as either normal or abnormal. However, the problem of improving the accuracy and efficiency of classification models remains open and yet to be resolved. This study proposes a new binary classification model for intrusion detection, based on hybridization of Artificial Bee Colony algorithm (ABC) and Dragonfly algorithm (DA) for training an artificial neural network (ANN) in order to increase the classification accuracy rate for malicious and non-malicious traffic in networks. At first the model selects the suitable biases and weights utilizing a hybrid (ABC) and (DA). Next, the neural network is retrained using these ideal values in order for the intrusion detection model to be able to recognize new attacks. Ten other metaheuristic algorithms were adapted to train the neural network and their performances were compared with that of the proposed model. In addition, four types of intrusion detection evaluation datasets were applied to evaluate the proposed model in comparison to the others. The results of our experiments have demonstrated a significant improvement in inefficient network intrusion detection over other classification methods

Effect of Sm-, Gd- codoping on structural modifications in aluminoborosilicate glasses under beta-irradiation

Two series of Sm-, Gd-codoped aluminoborosilicate glasses with different total rare earth content have been studied in order to examine the codoping effect on the structural modifications of beta-irradiated glasses. The data obtained by Electron Paramagnetic Resonance spectroscopy indicated that relative amount of Gd3+ ions located in network former position reveals non-linear dependence on Sm/Gd ratio. Besides, codoping leads to the evolution of the EPR signal attributed to defects created by irradiation: superhyperfine structure of boron oxygen hole centres EPR line becomes less noticeable and resolved with increase of Gd amount. This fact manifests that Gd3+ ions are mainly diluted in vicinity of the boron network. By Raman spectroscopy, we showed that the structural changes induced by the irradiation also reveal non-linear behaviour with Sm/Gd ratio. In fact, the shift of the Si-O-Si bending vibration modes has a clear minimum for the samples containing equal amount of Sm and Gd (50:50) in both series of the investigated glasses. In contrast, for single doped glass there is no influence of dopant's content on Si-O-Si shift (in case of Gd) or its diminution (in case of Sm) occurs which is explained by the reduction process influence. At the same time, no noticeable effect of codoping on Sm3+ intensity as well as on Sm2+ emission or on Sm reduction process was observed