Diagonalizing triangular matrices via orthogonal Pierce decompositions

A class of sufficient conditions is given to ensure that the sum a+b in a ring R, is equivalent to a sum x + y, which is an orthogonal Pierce decomposition. This is then used to show that a lower triangular matrix, with a regular diagonal is equivalent to its diagonal iff the matrix admits a lower triangular von Neumann inverse.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência, Tecnologia, Inovação” (POCTI)

Witnessing the birth of a supermassive protostar

The detection of $\rm z>6$ quasars reveals the existence of supermassive black holes of a few $\rm 10^9~M_{\odot}$. One of the potential pathways to explain their formation in the infant universe is the so-called direct collapse model which provides massive seeds of $\rm 10^5-10^6~M_{\odot}$. An isothermal direct collapse mandates that halos should be of a primordial composition and the formation of molecular hydrogen remains suppressed in the presence of a strong Lyman Werner flux. In this study, we perform high resolution cosmological simulations for two massive primordial halos employing a detailed chemical model which includes $\rm H^-$ cooling as well as realistic opacities for both the bound-free $\rm H^-$ emission and the Rayleigh scattering of hydrogen atoms. We are able to resolve the collapse up to unprecedentedly high densities of $\rm \sim 10^{-3}~g/cm^3$ and to scales of about $\rm 10^{-4}$ AU. Our results show that the gas cools down to $\rm \sim$ 5000 K in the presence of $\rm H^-$ cooling, and induces fragmentation at scales of about 8000 AU in one of the two simulated halos, which may lead to the formation of a binary. In addition, fragmentation also occurs on the AU scale in one of the halos but the clumps are expected to merge on short time scales. Our results confirm that $\rm H^-$ cooling does not prevent the formation of a supermassive star and the trapping of cooling radiation stabilises the collapse on small scales.Comment: Accpeted version, to appear in MNRAS, comments are still welcome and high resolution version is available at http://www2.iap.fr/users/latif/DCBH.pd

Essays on the Effects of Informal and Formal Protection Arrangements

__Abstract__ A feature of the development discourse in the past decade has been the emergence of large scale social safety net programmes in developing countries. In this thesis we look at the effects of different ‘safety net’ mechanisms, whereby the term ‘safety net’ is considered in a broader sense. The thesis does not only look at formal safety net programmes that are implemented by the government but also explores the effects of an informal social protection arrangement, i.e. the family, which acts as an important ‘safety net’ in contexts where formal protection mechanisms are not working or still fully absent

Annual Report Iowa State University Veterinary Medical Alumni Association

The Board of Directors of the Iowa State University Veterinary Medical Alumni Association met at the Marriot Hotel on Saturday, January 26, 1991. Members present were Wertman, Frey, Feldman, and Hartwig. The attached treasurer\u27s report and 1991 proposed budgetwas reviewed and approved by the board. The auditors report, performed by Drs. Roger Hogle and David Larson was accepted. The Board agreed to pay the cost of sending the secretary to the AVMA meeting in Seattle to sponsor the ISUVMAA receptio

Minutes: ISUVMAA Board Meeting

The meeting was called to order by President Wilgenbusch at 2 p.m. Members present were: Duke Wilgenbusch, Jerry Den Herder, Wendell Davis, Fred Wertman, Jim Sievers, and Nolan Hartwig. A treasurer\u27s report dated 5/26/88 (attached) was presented and accepted. The program for the Stange Banquet (attached) was also reviewed

Annual Meeting Iowa State University Veterinary Medical Alumni Association

The annual meeting was held at the Savery Hotel on January 23, 1994. Thirty-eight members attended. President Feldman called the meeting to order. Secretary/Treasurer Hartwig gave the treasurer\u27s report and presented the proposed budget for 1994. The budget was approved. He also reported on the College of Veterinary Medicine Alumni Association, sponsored alumni receptions at various national meetings during the last year and activites with regard to the ISU Veterinarian. He reported on progess to date on the Frank K. Ramsey Alumni Room Fund Drive. It was noted that approximately $28,000.00 has been raised to date and more will be needed to complete the remodeling and refurbishing. He displayed an artist\u27s drawing of the remodeled room, sample fabrics, and preliminary estimates of costs

Research on digital transducer principles. Volume 10 - Thin film titanium dioxide by chemical vapor deposition, 1 July - 31 December 1968

Thin film titanium dioxide by high temperature vapor depositio