Estimated constraints on t-channel Leptoquark exchange from LHC contact interaction searches

The t-channel exchange of a first generation leptoquark could contribute to the cross-section for q q-bar to e+e-. The leptoquark is off-shell, so this process can be sensitive to leptoquarks beyond the mass reach of pair production searches at the LHC (currently m_{LQ}> 830 GeV). We attempt to analytically translate ATLAS bounds on $(\bar{q} \gamma ^\mu q) (\bar{e} \gamma _\mu e)$ contact interactions to the various scalar leptoquarks, and obtain a bound on their quark-lepton coupling of order $\lambda^2 \leq (m_{LQ}/2$ TeV)$^2$. The greatest difficulty in this translation is that the leptoquarks do not induce the contact interaction studied by ATLAS, so the interference with the Standard Model is different. If bounds were quoted on the functional dependance of the cross-section on s-hat, rather than on particular contact interaction models, this difficulty in applying experimental bounds to theoretical models could be circumvented.Comment: 8 pages,3 figure

Inverse problem for a parabolic system with two components by measurements of one component

We consider a $2\times 2$ system of parabolic equations with first and zeroth coupling and establish a Carleman estimate by extra data of only one component without data of initial values. Then we apply the Carleman estimate to inverse problems of determining some or all of the coefficients by observations in an arbitrary subdomain over a time interval of only one component and data of two components at a fixed positive time $\theta$ over the whole spatial domain. The main results are Lipschitz stability estimates for the inverse problems. For the Lipschitz stability, we have to assume some non-degeneracy condition at $\theta$ for the two components and for it, we can approximately control the two components of the $2 \times 2$ system by inputs to only one component. Such approximate controllability is proved also by our new Carleman estimate. Finally we establish a Carleman estimate for a $3\times 3$ system for parabolic equations with coupling of zeroth-order terms by one component to show the corresponding approximate controllability with a control to one component

A New PVSS Scheme with a Simple Encryption Function

A Publicly Verifiable Secret Sharing (PVSS) scheme allows anyone to verify the validity of the shares computed and distributed by a dealer. The idea of PVSS was introduced by Stadler in [18] where he presented a PVSS scheme based on Discrete Logarithm. Later, several PVSS schemes were proposed. In [2], Behnad and Eghlidos present an interesting PVSS scheme with explicit membership and disputation processes. In this paper, we present a new PVSS having the advantage of being simpler while offering the same features.Comment: In Proceedings SCSS 2012, arXiv:1307.8029. This PVSS scheme was proposed to be used to provide a distributed Timestamping schem

Andalusi Masters in Bejaia. Their role in activating historical knowledge during the 13th century

Durante el siglo XIII, la ciudad de Bujía atrajo un considerable número de andalusíes ligados directamente al conocimiento de la historia, que se establecieron en la ciudad de forma provisional o permanente. Los que permanecieron en la ciudad centraron su actividad en la enseñanza de una serie de obras históricas y crónicas a sus estudiantes, que procedían de la propia ciudad de Bujía y de fuera de ella. Al examinar los datos históricos dispersos en los libros, programas e índices de estos maestros, además de los libros de biografías, descubrimos la importancia de la actividad historiográfica de los andalusíes en Bujía, y arrojamos luz sobre los alumnos más destacados y los títulos de las obras que se enseñaban. Esto influirá en el desarrollo de la conciencia historiográfica de Bujía en el siglo XIII, ligada a la escuela de historia andalusí representada por los maestros más destacados, como Ibn Sarrāǧ al-Išbīlī, Ibn al-Abbār al-Balansī, y Abū ˁAbdallāh Muḥammad ibn Ṣāliḥ al-Kinānī al-ŠāṭibīThought the 7th century of Al-hegira / the 13th Century of Birth, the city of Bejaia had attracted a considerable number of Andalusian elements linked directly to historical knowledge, who settled in the city either in a temporary or in permanent manner. The latter had stressed their activities on teaching a set of works on History and Chronicles for a group of students’ campus (episodes). If we look on the historical data spread in the folders of books programs and lecturers’ indexes, alongside with the books of biographies studied therein, we shall discover the reality of the historical activity that the Andalousians’ Senate in Bejaia had practiced. A spotlight had been thrown on the brilliant pupils, whom had learned historical disciplines (modules), also the tittles of the literature news that were taught in their campuses. This will affect the general path in the progression of the historical consciousness in Bejaia of the 7th /13th Century, where we observe its relation with the Andalusian historical school seen by its famous lecturers in the city such as Ibn- Sarrāj Al-Ishbīlī, Ibn Al-Abbār Al-Balansī and Abū ˁAbdallāh Muḥammad b. Ṣāliḥ Al-Kinānī Al- Shāṭibī

The Parliamentary Elections of Year 2000 in Egypt: A Lesson in Political Participation

The first and second issue of four volumes, this volume addresses elections in the Middle East. Contributors include: Assia Boutaleb, Judith Harik, Mona Markram-Ebeid, Christopher Parker, Curtis Francis Doebbler, Maye Kassem, Baskin Oran, Sami Zemni