On non-adjointable semi-Weyl and semi-B-Fredholm operators over C*-algebras

We extend further semi-A-Fredholm theory by generalizing the results from classical semi-Weyl theory on Hilbert spaces. Moreover, we obtain an analogue of the results from [17] in the setting of non-adjointable operators. Finally, we provide several examples on semi-A-Fredholm and semi- A-Weyl operators over a unital C*-algebra A. We give also the examples of semi-A-Fredholm operators with non-closed image

Experimental Study of Diamond Like Carbon (DLC) Coated Electrodes for Pulsed High Gradient Electron Gun

For the SwissFEL Free Electron Laser project at the Paul Scherrer Institute, a pulsed High Gradient (HG) electron gun was used to study low emittance electron sources. Different metals and surface treatments for the cathode and anode were studied for their HG suitability. Diamond Like Carbon (DLC) coatings are found to perform exceptionally well for vacuum gap insulation. A set of DLC coated electrodes with different coating parameters were tested for both vacuum breakdown and photo electron emission. Surface electric fields over 250MV/m (350 - 400kV, pulsed) were achieved without breakdown. From the same surface, it was possible to photo-emit an electron beam at gradients up to 150MV/m. The test setup and the experimental results are presentedComment: 4 pages, 14 figures, IPMHVC 2010 : IEEE International Power Modulator and High Voltage Conferenc

RESCUING THE ISCHEMIC PENUMBRA—OUR EXPIRIENCE

Objectives: Over one million strokes per year are occurring in Europe. Brain stroke is one of the most important death and disability causes in Europe and USA. The main role of perfusion is to determine the border of insult core and ischemic penumbra. Penumbra can be saved with thrombolytic therapy but core have irreversible injuries and represent death of brain cells. Aim: to determine the role of CT brain perfusion in cases of acute brain stroke and following thrombolytic therapy. Methods: We examined 64 patients with acute brain stroke who received thrombolytic therapy after that. All patients were examining on 16 MDCTwith 50 ml of iodine contrast agent following the standard procedure for CT perfusion. Patients were 34 male and 30 female with middle age of 64 years. MRI was made after thrombolytic therapy and compare with perfusion results before therapy. Results: Using an artery and a vein as reference three parameters were measured — blood flow (CBF), blood volume (CBV) and mean transit time (MTT), for each patient. Hemorrhagic was find in 9 (14.01%) patients after thrombolytic therapy. 4 (6.25%) other patients develop new stroke of same but mostly other side of brain. 8 (12.50%) more patients finished lethally. From other 42 patientswith thrombolytic therapywe can positively say that in 31 (48.44%) patients penumbrawas rescued. For other 11 (17.19%) stroke was same size like firstly involved core and penumbra but not bigger. Conclusion: CT perfusion plays major role by showing a curable parts of tissue in brain stroke

Oтворени приступ и развој научне комуникације

The Open Access approach enabled many publishers to make their articles visible for scientists. Although, Open Access publishing many scientists consider as an attractive alternative, the idea was not so fastly and easily accepted in practice. Due to increased visibility many articles are being increasedly cited. But, the quantitative approach to citation and impact factor has been criticized by several authors. Promotion of Open Access to researchers in Serbia has been hard and time-consuming work. Due to a lack of understanding there is a widely-held belief that “free” journals are not rigorously reviewed The main  problem  is  researchers’  doubts about the quality of open scientific journals. However, Open Access is very important approach and it should not be considered as an idea that solves all problems that researchers face in their publishing efforts. The librarians should support researchers to be involved in open access publishing and use existing existing repositories

Dynamic Windows Scheduling with Reallocation

We consider the Windows Scheduling problem. The problem is a restricted version of Unit-Fractions Bin Packing, and it is also called Inventory Replenishment in the context of Supply Chain. In brief, the problem is to schedule the use of communication channels to clients. Each client ci is characterized by an active cycle and a window wi. During the period of time that any given client ci is active, there must be at least one transmission from ci scheduled in any wi consecutive time slots, but at most one transmission can be carried out in each channel per time slot. The goal is to minimize the number of channels used. We extend previous online models, where decisions are permanent, assuming that clients may be reallocated at some cost. We assume that such cost is a constant amount paid per reallocation. That is, we aim to minimize also the number of reallocations. We present three online reallocation algorithms for Windows Scheduling. We evaluate experimentally these protocols showing that, in practice, all three achieve constant amortized reallocations with close to optimal channel usage. Our simulations also expose interesting trade-offs between reallocations and channel usage. We introduce a new objective function for WS with reallocations, that can be also applied to models where reallocations are not possible. We analyze this metric for one of the algorithms which, to the best of our knowledge, is the first online WS protocol with theoretical guarantees that applies to scenarios where clients may leave and the analysis is against current load rather than peak load. Using previous results, we also observe bounds on channel usage for one of the algorithms.Comment: 6 figure

Investment Bank Expertise in Cross-Border Mergers and Acquisitions

We study the influence of country expertise of investment banks in facilitating cross‐border merger deals by analyzing a large international sample of merger and acquisition (M&A) deals. We provide evidence that the geographical proximity, cultural affinity, and local experience of investment banks advising bidding firms on cross‐border M&A deals significantly increase the probability of completion of the deal, significantly decrease the time required to complete the deal, and significantly increase the operating performance of the acquiring firm after the deal. Our results are robust to firm, deal, country‐specific factors, and endogeneity concerns

Empirical comparison of high gradient achievement for different metals in DC and pulsed mode

For the SwissFEL project, an advanced high gradient low emittance gun is under development. Reliable operation with an electric field, preferably above 125 MV/m at a 4 mm gap, in the presence of an UV laser beam, has to be achieved in a diode configuration in order to minimize the emittance dilution due to space charge effects. In the first phase, a DC breakdown test stand was used to test different metals with different preparation methods at voltages up to 100 kV. In addition high gradient stability tests were also carried out over several days in order to prove reliable spark-free operation with a minimum dark current. In the second phase, electrodes with selected materials were installed in the 250 ns FWHM, 500 kV electron gun and tested for high gradient breakdown and for quantum efficiency using an ultra-violet laser.Comment: 25 pages, 13 figures, 5 tables. Follow up from FEL 2008 conference (Geyongju Korea 2008) New Title in JVST A (2010) : Vacuum breakdown limit and quantum efficiency obtained for various technical metals using DC and pulsed voltage source

On New Approach to Fredholm theory in unital C*-algebras

Motivated by the Fredholm theory on the standard Hilbert module over an unital C*-algebra introduced by Mishchenko and Fomenko, we provide a new approach to axiomatic Fredholm theory in unital C*-algebras established by Keckic and Lazovic in [28]. Our approach is equivalent to the approach introduced by Keckic and Lazovic, however, we provide new proofs which are motivated by the proofs given by Mishchenko and Fomenko