The modulus of elasticity of high performance concrete

To determine the modulus of elasticity of concrete precisely is very important for structures that require strict control of the deformability. International codes propose a wide variety of formulae which establish a relationship between modulus of elasticity and compressive strength. Most of these codes are valid up to 50 MPa, the usual limit for normal concretes. A research programme has been carried out to establish the modulus of elasticity-compressive strength curve for low and high strength concretes. The effect of the aggregate also has been studied. This is an important factor to take into account, sometimes more important than the concrete strength itself or even age. A model code formula provides good correlation with experiment up to a compressive strength of 120 MPa. Other aggregates not considered for this code have been studied and results given. Also, the influence of age on the modulus of elasticity is discussed.     

Comparative study of different test methods for reinforced concrete durability assessment in marine environment

There are many different test methods to assess reinforced concrete durability. As in marine environment reinforcement corrosion due to chloride attack is the most important degradation process, chloride penetration rate has been compared with different durability tests results (concrete strength, porosity, water absorption, water penetration depth under pressure, capillarity, water and oxygen permeability) carried out on concrete cores obtained from the caissons of seven Spanish wharves. Data have been studied separately, depending on concrete location (chloride penetration rate is faster in submerged concretes than in tidal zone concretes) and cement type (mineral admixtures reduce permeation rate due to pore size refinement). Results show that it is advisable to control concrete water tightness through water penetration under pressure test; additionally, in order to make sure a slow corrosion rate, it should be advisable to control oxygen permeability in tidal zone concretes.     

Women,peace and security state-of-art: a bibliometric analysis in social sciences based on SCOPUS database

To the best of our knowledge, there is no work that has focused on analysing the development of the scientific production on women, peace and security. The main objective of this paper is to cover this research gap through a bibliometric analysis, that covers 95 years (1918–2013), of articles published in peer-reviewed journals extracted from the SCOPUS database. Bibliometric indicators and laws have been applied to better understand the patterns that govern the scientific literature on this realm. A gender perspective has also been implemented in the analysis. The analysis provides quantitative results based on 321 articles published by 478 authors in 210 scientific journals. The data showed the high dispersion of the literature, both in terms of authors and journals focused on the topic, and a low level of collaboration among both authors and institutions. Regarding the research topic, half of the papers were related to the impact of conflict on civilians and civil society. The implementation of a gender perspective shows that most of the first, second and third authors of the papers are women. In terms of methodologies, qualitative methodologies are the most relevant and women are more prolific applying these methodology. In terms of geographical region of the research, most of the studies have been performed by authors from institutions in Anglo-Saxon countries, and most of the fieldwork has been focused on the United States and the main areas of conflict in the world throughout history. Finally, important research opportunities are identified.     

pH-sensitive capsules as intracellular optical reporters for monitoring lysosomal pH changes upon stimulation

The concept of a long-term sensor for ion changes in the lysosome is presented. The sensor is made by layer-by-layer assembly of oppositely charged polyelectrolytes around ion-sensitive fluorophores, in this case for protons. The sensor is spontaneously incorporated by cells and resides over days in the lysosome. Intracellular changes of the concentration of protons upon cellular stimulation with pH-active agents are monitored by read-out of the sensor fluorescence at real time. With help of this sensor concept it is demonstrated that the different agents used (Monensin, Chloroquine, Bafilomycin A1, Amiloride) possessed different kinetics and mechanisms of action in affecting the intracellular pH values.     

Plasmon resonant amplification of a hot electron-driven photodiode

Nano Research - We report plasmon resonant excitation of hot electrons in a photodetector based on a metal/oxide/metal (Au/Al2O3/graphene) heterostructure. In this device, hot electrons, excited...     

Polymer-coated nanoparticles: a universal tool for biolabelling experiments

Water solubilization of nanoparticles is a fundamental prerequisite for many biological applications. To date, no single method has emerged as ideal, and several different approaches have been successfully utilized. These 'phase-transfer' strategies are reviewed, indicating key advantages and disadvantages, and a discussion of conjugation strategies is presented. Coating of hydrophobic nanoparticles with amphiphilic polymers provides a generic pathway for the phase transfer of semiconductor, magnetic, metallic, and upconverting nanoparticles from nonpolar to polar environments. Amphiphilic polymers that include maleimide groups can be readily functionalized with chemical groups for specific applications. In the second, experimental part, some of the new chemical features of such polymer-capped nanoparticles are demonstrated. In particular, nanoparticles to which a pH sensitive fluorophore has been attached are described, and their use for intracellular pH-sensing demonstrated. It is shown that the properties of analyte-sensitive fluorophores can be tuned by using interactions with the underlying nanoparticles.     

Heuristic algorithms for a storage location assignment problem in a chaotic warehouse

The extensive application of emerging technologies is revolutionizing warehouse management. These technologies facilitate working with complex and powerful warehouse management models in which products do not have assigned fixed locations (random storage). Random storage allows the utilization of the available space to be optimized. In this context, and motivated by a real problem, this article presents a model that looks for the optimal allocation of goods in order to maximize the storage space availability within the restrictions of the warehouse. For the proposed model a construction method, a local search algorithm and different metaheuristics have been developed. The introduced algorithms can also be used for other purposes such as to assess when and how it is convenient to perform relocation of stored items to improve the current level of storage space availability. Computational tests performed on a set of randomly generated and real warehouse instances show the effectiveness of the proposed methods.     

Improvements on enzymatic hydrolysis of human hair for illicit drug determination by gas chromatography/mass spectrometry

The use of ultrasound energy for accelerating the pronase E enzymatic hydrolysis of human hair for extracting illicit drugs has been novelty tested. The enzymatic extracts obtained after 30 min of sonication in an ultrasonic water bath were subjected to an optimized solid-phase extraction process, which involved a solution of 2.0% (v/v) acetic acid in methanol as eluting solution and concentration by N2 stream evaporation. A gas chromatography/mass spectrometry method was used to separate and determine cocaine, benzoylecgonine, codeine, morphine, and 6-monoacethylmorphine in 20 min. Variables affecting ultrasound-assisted pronase E hydrolysis such as hydrolysis temperature, hydrolysis time, enzyme concentration, catalyzer (1,4-dithiothreitol) concentration, ionic strength, pH, and ultrasound frequency were simultaneously evaluated by a Plackett-Burman design 2(8) PBD of resolution III. The most statistically significant variables were ionic strength and pH, which means that analyte extraction is mainly attributed to pronase E activity. The optimization or evaluation of all the factors has led to an accelerated pronase E hydrolysis of human hair, which can be completed in 30 min. Results have been found to be statistically similar to those obtained with conventional pronase E hydrolysis. The accelerated method was finally applied to several human hair samples from multidrug abusers.     

Multi-armed Bandit processes with optimal selection of the operating times

A multi-armed Bandit Problem is considered such that at each decision epoch it is to be decided the next project to be undertaken and the span of time to be spent in this project, instead of reconsidering the new project at each stage. This extended model, inspired in sequentially planned decision procedures (Schmitz, 1993), is formulated in Section 1 and tries to exploit the reduction of costs produced by longer periods dedicated to the same activity. Following the method by Whittle (1980). Section 2 introduces a retirement option with a variable rewardM, and Section 3 extends Gittins indexes to this case. Another relevant conclusion is that the optimal period of activity for each project does not depend on the retirement rewardM. Finally, we show that the optimal strategy is to choose the project with the highest Gittins index.     

Preserved monitoring and control processes in temporal lobe epilepsy.

Objective: The aim of this study was to assess an aspect of metamemory never examined before in patients with temporal lobe epilepsy (TLE): the ability to upgrade the accuracy of one's memory predictions after study. Method: Four lists of different levels of difficulty and relatedness were presented to 15 TLE patients and 15 control participants, who were asked to predict their subsequent recall both before and after studying each list. Results: The results showed clear impairment in recall in TLE patients. However, both TLE patients and controls showed an improvement in accuracy in their poststudy predictions compared with their prestudy predictions, showing that both groups were able to upgrade their metamemory predictions. Unexpectedly, prediction accuracy was overall higher in TLE patients than in controls. Moreover, study time was allocated in both groups taking into account the characteristics of the list. Conclusion: These results confirm and extend findings of Howard et al. (2010) of intact metamemory in TLE patients, and provide further support to the dissociation between memory and metamemory in this clinical population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)