Power densities for two-step gamma-ray transitions from isomeric states

We have calculated the incident photon power density P_2 for which the two-step induced emission rate from an isomeric nucleus becomes equal to the natural isomeric decay rate. We have analyzed two-step transitions for isomeric nuclei with a half-life greater than 10 min, for which there is an intermediate state of known energy, spin and half-life, for which the intermediate state is connected by a known gamma-ray transition to the isomeric state and to at least another intermediate state, and for which the relative intensities of the transitions to lower states are known. For the isomeric nucleus 166m-Ho, which has a 1200 y isomeric state at 5.98 keV, we have found a value of P_2=6.3 x 10^7 W cm^{-2}, the intermediate state being the 263.8 keV level. We have found power densities P_2 of the order of 10^{10} W cm^{-2} for several other isomeric nuclei.Comment: 9 pages, 1 eps figure, 1 tabl

Emission of gamma rays shifted from resonant absorption by electron-nuclear double transitions in ^{151}Eu^{2+}:CaF_2

We show that the emission of a gamma-ray photon by a nucleus can be influenced by a microwave magnetic field acting on the atomic electrons. We study theoretically these electron-nuclear double transitions (ENDTs) for ^{151}Eu nuclei in a CaF_2 lattice at low temperature, in the presence of a static magnetic field and of a microwave magnetic field. The ENDTs acquire a significant intensity for certain resonance frequencies. The ENDTs are of interest for the identification of the position of the lines in complex M\"{o}ssbauer spectra.Comment: 8 pages; 3 Postscript figures: Fig. 1, Fig. 2(a), Fig. 2(b

On a unique tree representation for P4-extendible graphs

AbstractSeveral practical applications in computer science and computational linguistics suggest the study of graphs that are unlikely to have more than a few induced paths of length three. These applications have motivated the notion of a cograph, defined by the very strong restriction that no vertex may belong to an induced path of length three. The class of P4-extendible graphs that we introduce in this paper relaxes this restriction, and in fact properly contains the class of cographs, while still featuring the remarkable property of admitting a unique tree representation. Just as in the case of cographs, the class of P4-extendible graphs finds applications to clustering, scheduling, and memory management in a computer system. We give several characterizations for P4-extendible graphs and show that they can be constructed from single-vertex graphs by a finite sequence of operations. Our characterization implies that the P4-extendible graphs admit a tree representation unique up to isomorphism. Furthermore, this tree representation can be obtained in polynomial time

A tree representation for P4-sparse graphs

AbstractA graph G is P4-sparse if no set of five vertices in G induces more than one chordless path of length three. P4-sparse graphs generalize both the class of cographs and the class of P4-reducible graphs. We give several characterizations for P4-sparse graphs and show that they can be constructed from single-vertex graphs by a finite sequence of operations. Our characterization implies that the P4-sparse graphs admit a tree representation unique up to isomorphism. Furthermore, this tree representation can be obtained in polynomial time

Fast Inner Product Computation on Short Buses

We propose a VLSI inner product processor architecture involving broadcasting only over short buses (containing less than 64 switches). The architecture leads to an efficient algorithm for the inner product computation. Specifically, it takes 13 broadcasts, each over less than 64 switches, plus 2 carry-save additions (tcsa) and 2 carry-lookahead additions (tcla) to compute the inner product of two arrays of N = 29 elements, each consisting of m = 64 bits. Using the same order of VLSI area, our algorithm runs faster than the best known fast inner product algorithm of Smith and Torng [ Design of a fast inner product processor, Proceedings of IEEE 7th Symposium on Computer Arithmetic (1985)], which takes about 28 tcsa + tcla for the computation

Reconfigurable Shift Switching Parallel Comparators

We present novel asynchronous VLSI comparator schemes which are based on recently proposed reconfigurable shift switch logic and the traditional (precharged) CMOS domino logic. The schemes always produce a semaphore as a by-product of the process to indicate the end of domino process, which requires no additional delay and a minimal number of additional devices. For a large percentage of inputs the computations are much faster than traditional synchronous comparators due to the full utilization of the inherent speed of the circuits. Also the schemes are simple, area compact and stable

A Mergeable Double-Ended Priority Queue

An implementation of a double-ended priority queue is discussed. This data structure referred to as min–max–pair heap can be built in linear time; the operations Delete-min, Delete-max and Insert take O(log n) time, while Find-min and Find-max run in O(1) time. In contrast to the min-max heaps, it is shown that two min–max–pair heaps can be merged in sublinear time. More precisely, two min–max–pair heaps of sizes n and k can be merged in time O(log (n/k) * log k)

A Linear-Time Recognition Algorithm for P4-Reducible Graphs

The P4-reducible graphs are a natural generalization of the well-known class of cographs, with applications to scheduling, computational semantics, and clustering. More precisely, the P4-reducible graphs are exactly the graphs none of whose vertices belong to more than one chordless path with three edges. A remarkable property of P4-reducible graphs is their unique tree representation up to isomorphism. In this paper we present a linear-time algorithm to recognize P4-reducible graphs and to construct their corresponding tree representation

An Optimal Path Cover Algorithm for Cographs

The class of cographs, or complement-reducible graphs, arises naturally in many different areas of applied mathematics and computer science. In this paper, we present an optimal algorithm for determining a minimum path cover for a cograph G. In case G has a Hamiltonian path (cycle) our algorithm exhibits the path (cycle) as well

Giant hernia patient, particular aspects in treatment and surgical approach - case presentation

Universitatea de Medicină și Farmacie „Victor Babeș”, Clinica I Chirurgie, Spitalul Clinic Judeţean de Urgenţă „Pius Brinzeu”, Timișoara, România, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaIntroducere: Herniile abdominale gigante sunt patologii mai rar întalnite în zilele noastre, dar pot ridica probleme deosebite în terapie. Scopul: Prezentarea unui caz particular al unui pacient cu hernie de linie albă abdominală voluminoasă. Material şi metode: Pacient obez, cunoscut cu hipertensiune arterială, insuficiență venoasă cronică, ce prezintă hernie de linie albă abdominală gigantă cu dimensiunile aproximative 30/35/15cm, cu leziuni locale cutanate tegumentare de decubit, afirmativ debutată în urmă cu peste 10 ani, se interenază în clinica noastră pentru tratament electiv. La tentativa de cură chirurgicală a defectului parietal prin procedeu anatomic, se constată o scădere bruscă a saturației de oxigen (sub 90%), impunandu-se repararea herniei cu material protetic. S-a practicat cura chirurgicală cu plasă de substituție din polipropilenă, reanatomizare. Rezultate: Evoluția post operatorie a fost favorabilă, pacientul fiind externat în ziua 8 postoperator. Procedeele chirurgicale certificate în literatura de specialitate trebuiesc adaptate particularității cazurilor. Concluzii: Managementul pacienților cu hernii ventrale voluminoase este complex, atât din punct de vedere operator, cat și medical, și necesită în multe cazuri colaborare interdisciplinară, controlul afecțiunilor asociate și schimbarea stilului de viață fiind aspecte fundamentale ce influențează evoluția cazului.Introduction: Giant abdominal hernias are rare nowadays, but in those cases, treatment could be difficult. Aim: Presentation of a particular case of giant ventral hernia. Material and methods: Obese, hypertensive patient, with chronic venous insufficiency, presents giant ventral hernia associated with local skin lesions (approximate dimensions 30/35/15 centimeters), with over ten years of evolution. At the attempt of anatomically procedure hernia repair, oxygen saturation decrease occurs (<90%), so we performed substitution mesh hernia repair, anatomically closure. Results: Favorable postoperative evolution. The patient was discharged after 8 post-operative days surgically cured. Surgical procedures and technique had to be adapted to each particular case. Conclusions: Patients with giant ventral hernias treatment is complex, from surgical and medical view. Interdisciplinary medical team could be required. Related diseases and weight control are important aspects for a good outcome