Canonical-grandcanonical ensemble in-equivalence in Fermi systems?

I discuss the effects of fermionic condensation in systems of constant density of states. I show that the condensation leads to a correction of the chemical potential and of the Fermi distribution in canonical Fermi systems at low temperatures. This implies that the canonical and grandcanonical ensembles are not equivalent even for Fermi systems.Comment: 4 pages and 1 figur

Fluctuations of the Fermi condensate in ideal gases

We calculate numerically and analytically the fluctuations of the fermionic condensate and of the number of particles above the condensate for systems of constant density of states. We compare the canonical fluctuations, obtained from the equivalent Bose condensate fluctuation, with the grandcanonical fermionic calculation. The fluctuations of the condensate are almost the same in the two ensembles, with a small correction comming from the total particle number fluctuation in the grandcanonical ensemble. On the other hand the number of particles above the condensate and its fluctuation is insensitive to the choice of ensemble.Comment: 10 pages with 3 figs. IOP styl

Exploring student perspectives on the extended program

Abstract: Many students find the transition from high school to university difficult specifically in engineering. It has been established that there is a gap in mathematics ability between high school and university. Internationally the high school curricula focuses on increasing access to tertiary institutions. Many of these curricula teach superficial learning to high school students. At University level deep learning is required. Students who do not meet entry requirements for engineering first year have the option to enter an extended program. This paper explores whether the extended program offered at the University of Johannesburg for mechanical and industrial engineering students is perceived as beneficial. A survey was conducted on first and second year students that started their qualification with the extended program. The results were statistically analysed. Information from the Higher Education Management Information System (HEMIS) system was used to compare performance of students who completed the extended program and those in the mainstream. Based on the research it seems that the extended program does benefit students

Exploring student perspectives on an extended mechanical and industrial engineering program

Many students find the transition from high school to university difficult specifically in engineering. It has been established that there is a gap in mathematics ability between high school and university. Internationally the high school curricula focus on increasing access to tertiary institutions. Many of these curricula teach superficial learning to high school students. At University level deep learning is required. Students who do not meet entry requirements for engineering first year have the option to enter an extended program. This paper explores whether the extended program offered at the University of Johannesburg for mechanical and industrial engineering students is perceived as beneficial. A survey was conducted on first- and second-year students that started their qualification with the extended program. The results were statistically analysed. Information from the Higher Education Management Information System (HEMIS) system was used to compare performance of students who completed the extended program and those in the mainstream. Based on the research it seems that the extended program does benefit students.Institute for Science and Technology Education (ISTE

Universal behaviour of ideal and interacting quantum gases in two dimensions

I discuss ideal and interacting quantum gases obeying general fractional exclusion statistics. For systems with constant density of single-particle states, described in the mean field approximation, the entropy depends neither on the microscopic exclusion statistics, nor on the interaction. Such systems are called {\em thermodynamically equivalent} and I show that the microscopic reason for this equivalence is a one-to-one correspondence between the excited states of these systems. This provides a method, different from the bosonisation technique, to transform between systems of different exclusion statistics. In the last section the macroscopic aspects of this method are discussed. In Appendix A I calculate the fluctuation of the ground state population of a condensed Bose gas in grandcanonical ensemble and mean field approximation, while in Appendix B I show a situation where although the system exhibits fractional exclusion properties on microscopic energy intervals, a rigorous calculation of the population of single particle states reveals a condensation phenomenon. This also implies a malfunction of the usual and simplified calculation technique of the most probable statistical distributions.Comment: About 14 journal pages, with 1 figure. Changes: Body of paper: same content, with slight rephrasing. Apendices are new. In the original submission I just mentioned the condensation, which is now detailed in Appendix B. They were intended for a separate paper. Reason for changes: rejection from Phys. Rev. Lett., resubmission to J. Phys. A: Math. Ge

Malignant tumor with different localisation after klatskin tumor succesfully resected

Institutul Clinic Fundeni, Clinica Chirurgie Generală și Transplant Hepatic “Dan Setlacec”, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Prezentare de caz: tumora Klatskin IIIb rezecată cu evoluția postoperatorie bună, diagnosticat la 3 ani cu tumoră gastrică.Case report: IIIb Klatskin tumor successfully resected with good postoperative outcome is diagnosed 3 years later with a gastric tumor