Correlations of projectile like fragments in heavy ion reactions at Fermi energy

Correlations between pairs of projectile-like fragments, emitted by the system ${^{16}O}+{^{197}Au}$ at the laboratory bombarding energy of 515 MeV, have been studied under two stipulated conditions: (1) at least one member of the pair is emitted at an angle less than the grazing angle for the system, (2) both the members of the pair are emitted at angles larger than the grazing angle. A surprisingly large difference, by more than an order of magnitude, is found between the correlations for the two cases. This observation could be explained on the basis of a simple semi-classical break up model. Further analysis of the variation of the charge correlation function with the difference in the nuclear charges of the correlated pair showed trends which are consistent with an "inelastic break up process", in which the projectile breaks up at the radius of contact, in such a way that, one fragment (preferably the lighter) is emitted to one side within the grazing angle, while the other orbits around the target nucleus for a while and emerges on the other side, at a negative scattering angle, much like in a deep inelastic scattering.Comment: 19 pages, 12 figures accepted by Eurp. Physics Journal

Extended instantons generated on the lattice

We have been able to observe directly extended instantons on the lattice, with a new method that does not require dislocations to measure them, and where we do not perform cooling. We showed, based on the simple Abelian Higgs model in $1+1$ dim., that one can extract the instanton and anti-instanton density and their size, by measuring the topological charge, $Q_v$ , on sub-volumes $v$ larger than the instanton sizes, but smaller than the periodic lattice of size $V$. We are working on the generalization for non-abelian models.Comment: Talk presented at the LATTICE96(topology) ,uuencoded 3 pp in Latex, 1 ps fig., uses espcrc2.sty and epsf to include fi

Resilience to crisis and resistance to change: a comparative analysis of the determinants of crisis outcomes in Latin American regional organisations

Latin American regionalism displays a long history of crises, which have affected almost all regional organisations (ROs) across different waves of regionalism. The article conducts the first comparative analysis of the outcomes of crises in Latin American ROs across time, tackling the following questions: What have been the outcomes of the crises faced by Latin American ROs? Under what conditions does a crisis result in the survival or breakdown of the affected RO in Latin America? We adopt a multi-method approach that combines QCA with process tracing to identify the causal pathways to the survival or breakdown of ROs across a universe of eight crises. The findings show that Latin American ROs have been resilient to crises, which resulted in RO survival in seven cases out of eight. The QCA reveals how the distributive nature of interstate conflicts and the availability of majority voting are both sufficient conditions for Latin American ROs to survive a crisis. Analysis of the outlier case of UNASUR shows that normative conflicts that take place in the absence of majority voting constitute a 'perfect storm' configuration that can lead to RO breakdown. The findings also show that Latin America ROs' tendency to survive crises is associated with the preservation of the status quo in terms of institutional design, which in some cases is achieved through the temporary flexibilisation of existing rules. Differently from the case of the EU, then, the crises of Latin American ROs have not led to the deepening of regional integration, but rather to institutional inertia

Computerassistierte Chirurgie der Nasennebenhöhlen und der vorderen Schädelbasis

Zusammenfassung: Endoskopische oder mikroskopische Eingriffe bei chronischen Nasennebenhöhlenentzündungen mit oder ohne Polyposis sind in der täglichen Praxis häufig. Da es sich um delikate und schwierige minimal-invasive Eingriffe bei engem Raum, Tunnelblick von 4-mm-Endoskopen und häufig leicht blutendem Gewebe bei chronisch entzündlichen Erkrankungen handelt, ist die Orientierung in diesem "Labyrinth" oft schwierig. Bei Rezidiven von Nasenpolypen oder Tumoren sind oft die normalen anatomischen Landmarken, welche dem Chirurgen als Orientierung dienen, nicht mehr vorhanden. Die Navigation zusammen mit den Bildgebungsverfahren wie CT und MRT hilft bei unübersichtlichen Verhältnissen dem Chirurgen, sich im Raum zu orientieren und die Operation umso sicherer und z.T. auch schneller durchzuführen. Zusätzlich hat die Navigation ein großes Potenzial für Ausbildungszweck