The security of databases: the Access case

Nowadays, more and more companies have to use databases in which they store their essential or confidential data for the society like client lists, product specifications, stock situations, etc.. Such pieces of data are the heart of a company and have to be protected. In fact, in the context of economic intelligence, getting such information is quite interesting for competitors who want to know how rival companies work for example. Databases need software to be managed. There is a variety of software, called database management system, which is able to manage database like MySQL, Oracle Database, Microsoft Access, etc... This paper will focus on Microsoft Access 2010 64 bits which is part of the Microsoft Office 2010 suite. Microsoft Access is currently used by small and medium enterprises (SMEs) who have subcontracted the creation of their database to specialized companies. SMEs represent a huge part of the economic area and could be an interesting target because of the large range of activities it gather. This technical paper analyses the Access Security and explains how an attacker could hijack an Access database in order to steal information or to perform malicious actions on the targeted computer. It deals with macro-viruses, still present after many years, and give then the possibility to use them to insert major security weaknesses into Access databases.     

“Solving” ambiguity in the virtual space: communication strategies in a collaborative virtual environment

Collaborative virtual environments (CVE) face the challenge of succeeding in incorporating critical dimensions of cooperation and communication in everyday working situations. One of these dimensions, situation ambiguity, is scarcely considered in studies on CVE although it can prove a key factor in future use of CVE in real work situations. Many computer-supported cooperative environments and telecommunication systems, like those currently used in telemedicine, would benefit from the incorporation of some degree of situation ambiguity allowing users to deploy their diagnostic and interpretive abilities. In the perspective adopted in this study, ambiguity is the contingent outcome of the ongoing interaction taking place between the environment and the interests of social actors. The research focuses on the cooperation within couples of participants facing situation ambiguity in a virtual environment: a simulated city named Babylon. Participants moved in the city through an avatar and could communicate in one of the following conditions: face-to-face, phone or chat. Their goal was that of meeting somewhere in the city, in a place that they did not know previously. Babylon contained elements designed to allow both production and detection of ambiguity. Ambiguity emerged when participants realized the presence of inconsistencies in the way they perceived the situations they had to face. The moments in which ambiguity was perceived—called “critical events” (CE)—were measured and described through qualitative (ethnographically oriented) methods. The different strategies that participants used to “solve” ambiguity were characterized as: looking for environmental cues, narrowing the focus of attention and investing on cooperation. Both CEs and strategies were analyzed with respect to the three communication conditions: face-to-face, phone and chat. All the communication conditions allowed the emergence of ambiguity and the negotiation of strategies to solve ambiguity between partners: according to literature, chat is very costly in terms of time spent on writing but this disadvantage did not block completely the emergence of ambiguity and the development of adequate strategies of solution. All navigations but three (on a total of 18 couples) succeeded: the partners did meet in a short time (less than 15 min) relying on their pragmatic resources in a new virtual place. Further research is required to clarify the possible factors influencing the choice of one strategy over the others, the order in which strategies follow each other and the role of leadership in ambiguity detection and solution.     

P2P storage systems: Study of different placement policies

In a P2P storage system using erasure codes, a data block is encoded in many redundancy fragments. These fragments are then sent to distinct peers of the network. In this work, we study the impact of different placement policies of these fragments on the performance of storage systems. Several practical factors (easier control, software reuse, latency) tend to favor data placement strategies that preserve some degree of locality. We compare three policies: two of them are local, in which the data are stored in logical neighbors, and the other one, global, in which the data are spread randomly in the whole system. We focus on the study of the probability to lose a data block and the bandwidth consumption to maintain such redundancy. We use simulations to show that, without resource constraints, the average values are the same no matter which placement policy is used. However, the variations in the use of bandwidth are much more bursty under the local policies. When the bandwidth is limited, these bursty variations induce longer maintenance time and henceforth a higher risk of data loss. We then show that a suitable degree of locality could be introduced in order to combine the efficiency of the global policy with the practical advantages of a local placement. Additionally, we propose a new external reconstruction strategy that greatly improves the performance of local placement strategies. Finally, we give analytical methods to estimate the mean time to the occurrence of data loss for the three policies.     

Growing Chinese coal use: Dramatic resource and environmental implications

Chinese coal consumption continues to rise as the country's economy and industry expand. Coal is particularly critical for China's fast-growing power sector, generating about 80% of electricity output. Notwithstanding the importance of coal and electricity, many international forecasts today underestimate their rising use in China. This paper acknowledges the current world financial crisis and assumes that Chinese GDP growth to 2025 will not again approach double-digit levels. Using the scenario analysis, this paper demonstrates that even with conservative assumptions about Chinese GDP growth and income elasticity of electric demand to 2025, the country will likely experience much higher coal demand and emit much greater volumes of carbon dioxide than forecast by various international energy agencies. The paper also analyzes how China's domestic coal reserves may be threatened within two decades, possibly affecting long-term economic growth in China, as well as world coal prices.     

Beitrag zur Erfassung einiger rheologischer Eigenschaften von Weizenkleber

Contribution to Assessment of some Rheological Properties of Wheat Gluten. The production of wheat gluten has increased considerably in the recent times and producers of vital gluten are searching for new markets and applications. Its main functional properties can be characterised by means of rheometry. Some possibilities offered by the empirical and basic rheometry in recording the viscosity and elasticity of rehydrated vital gluten and of vital and modified gluten dispersed in different solvents, are shown. Both, the properties of gluten and the ability of solvents in modifying the gluten, can be monitored. A standardised preparation of test samples and of carrying out the measurements is required for obtaining reliable measuring data.     

AB186 Inhibits Migration of Triple-Negative Breast Cancer Cells and Interacts with α-Tubulin

Breast cancer is one of the leading causes of cancer-related death among females worldwide. A major challenge is to develop innovative therapy in order to treat breast cancer subtypes resistant to current treatment. In the present study, we examined the effects of two Troglitazone derivatives Δ2-TGZ and AB186. Previous studies showed that both compounds induce apoptosis, nevertheless AB186 was a more potent agent. The kinetic of cellular events was investigated by real-time cell analysis system (RTCA) in MCF-7 (hormone dependent) and MDA-MB-231 (triple negative) breast cancer (TNBC) cells, followed by cell morphology analysis by immuno-localization. Both compounds induced a rapid modification of both impedance-based signals and cellular morphology. This process was associated with an inhibition of cell migration measured by wound healing and transwell assays in TNBC MDA-MB-231 and Hs578T cells. In order to identify cytoplasmic targets of AB186, we performed surface plasmon resonance (SPR) and pull-down analyses. Subsequently, 6 cytoskeleton components were identified as potential targets. We further validated α-tubulin as one of the direct targets of AB186. In conclusion, our results suggested that AB186 could be promising to develop novel therapeutic strategies to treat aggressive forms of breast cancer such as TNBC.     

Regioselective Acetylation of C21 Hydroxysteroids by the Bacterial Chloramphenicol Acetyltransferase I

Chloramphenicol acetyltransferase I (CATI) detoxifies the antibiotic chloramphenicol and confers a corresponding resistance to bacteria. In this study we identified this enzyme as a steroid acetyltransferase and designed a new and efficient Escherichia‐coli‐based biocatalyst for the regioselective acetylation of C21 hydroxy groups in steroids of pharmaceutical interest. The cells carried a recombinant catI gene controlled by a constitutive promoter. The capacity of the whole‐cell system to modify different hydroxysteroids was investigated, and NMR spectroscopy revealed that all substrates were selectively transformed into the corresponding 21‐acetoxy derivatives. The biotransformation was optimized, and the reaction mechanism is discussed on the basis of a computationally modeled substrate docking into the crystal structure of CATI.     

On Modeling Hydrogen-Induced Crack Propagation Under Sustained Load

The failure of hydrogen containment components is generally associated with subcritical cracking. Understanding subcritical crack growth behavior and its dependence on material and environmental variables can lead to methods for designing structural components in a hydrogen environment and will be beneficial in developing materials resistant to hydrogen embrittlement. In order to identify the issues underlying crack propagation and arrest, we present a model for hydrogen-induced stress-controlled crack propagation under sustained loading. The model is based on the assumptions that (I) hydrogen reduces the material fracture strength and (II) crack propagation takes place when the opening stress over the characteristic distance ahead of a crack tip is greater than the local fracture strength. The model is used in a finite-element simulation of crack propagation coupled with simultaneous hydrogen diffusion in a model material through nodal release. The numerical simulations show that the same physics, i.e., diffusion-controlled crack propagation, can explain the existence of both stages I and II in the velocity versus stress intensity factor (V–K) curve.     

Anodic aqueous electrophoretic deposition of titanium dioxide using carboxylic acids as dispersing agents

The dispersion of anatase phase TiO₂ powder in aqueous suspensions was investigated by zeta-potential and agglomerate size analysis. The iso-electric point (IEP) of anatase was determined to be at pH 2.8 using monoprotic acids for pH adjustment. In comparison, it was found that the use of carboxylic acids, citric and oxalic, caused a decrease in zeta-potential through the adsorption of negatively charged groups to the particle surfaces. The use of these reagents was shown to enable effective anodic electrophoretic deposition (EPD) of TiO₂ onto graphite substrates at low pH levels with a decreased level of bubble damage in comparison with anodic EPD from basic suspensions. The results obtained demonstrate that the IEP of TiO₂ varies with the type of reagent used for pH adjustment. The low pH level of the IEP and the ability to decrease the zeta-potential through the use of carboxylic acids suggest that the anodic EPD of anatase is more readily facilitated than cathodic EPD.