Kinetics and moving species during Co2Si formation by rapid thermal annealing

We have investigated the growth kinetics and identified the moving species during Co2Si formation by rapid thermal annealing (RTA). For the kinetics study, samples which consisted of a thin Co film on an evaporated Si substrate were used. To study which species moves, samples imbedded with two very thin Ta markers were employed. Upon RTA, only one silicide phase, Co2Si, was observed to grow before all Co was consumed. The square root of time dependence and the activation energy of about 2.1±0.2 eV were observed during the Co2Si formation up to 680 °C. The marker study indicated that Co is the dominant mobile species during Co2Si formation by RTA. We conclude that Co2Si grows by the same mechanisms during RTA and conventional thermal annealing

Standoff Detection via Single-Beam Spectral Notch Filtered Pulses

We demonstrate single-beam coherent anti-Stokes Raman spectroscopy (CARS), for detecting and identifying traces of solids, including minute amounts of explosives, from a standoff distance (>50 m) using intense femtosecond pulses. Until now, single-beam CARS methods relied on pulse-shapers in order to obtain vibrational spectra. Here we present a simple and easy-to-implement detection scheme, using a commercially available notch filter, that does not require the use of a pulse-shaper.Comment: 3 pages, 3 figure

Moždana vazomotorna reaktivnost i okluzivna bolest karotidnih arterija

Cerebral autoregulation is a mechanism that enables relatively constant cerebral blood flow during variations of cerebral perfusion pressure. The differences between cerebral blood flow at rest and after administration of a potent vasodilatory stimulus test such as hypercapnia reflect cerebral vasomotor reactivity defined as the vasodilation capacity of cerebral arterioles to external stimuli, providing important information about the cerebral hemodynamic status. Cerebral vasomotor reactivity provides important information about the cerebral hemodynamic status. In this article, cerebral vasomotor reactivity assessment tests are presented, with emphasis on transcranial Doppler, as well as the use of transcranial Doppler in assessing cerebral vasomotor reactivity in carotid stenosis, occlusion, and the importance of cerebral vasomotor reactivity for carotid surgery.Moždana autoregulacija je mehanizam koji omogućava relativno ustaljeni moždani protok krvi za vrijeme promjena tlaka prokrvljenosti mozga. Razlike između moždanog protoka krvi u mirovanju i nakon testa snažne vazodilatacijske stimulacije poput hiperkapnije odražavaju moždanu vazomotornu reaktivnost definiranu kao vazodilatacijski kapacitet moždanih arteriola za vanjske poticaje, pružajući važne podatke o moždanom hemodinamskom statusu. Moždana vazomotorna reaktivnost daje važne informacije o statusu moždane hemodinamike. U članku se prikazuju testovi za procjenu moždane vazomotorne reaktivnosti s naglaskom na transkranijski Doppler, te primjena transkranijskog Dopplera u procjeni moždane vazomotorne reaktivnosti kod karotidne stenoze, okluzije, kao i važnost moždane vazomotorne reaktivnosti za kirurgiju karotidnih arterija

Vassiliev Invariants for Links from Chern-Simons Perturbation Theory

The general structure of the perturbative expansion of the vacuum expectation value of a product of Wilson-loop operators is analyzed in the context of Chern-Simons gauge theory. Wilson loops are opened into Wilson lines in order to unravel the algebraic structure encoded in the group factors of the perturbative series expansion. In the process a factorization theorem is proved for Wilson lines. Wilson lines are then closed back into Wilson loops and new link invariants of finite type are defined. Integral expressions for these invariants are presented for the first three primitive ones of lower degree in the case of two-component links. In addition, explicit numerical results are obtained for all two-component links of no more than six crossings up to degree four.Comment: 44 pages, LaTex, epsf.sty, 15 figure

A TQFT associated to the LMO invariant of three-dimensional manifolds

We construct a Topological Quantum Field Theory (in the sense of Atiyah) associated to the universal finite-type invariant of 3-dimensional manifolds, as a functor from the category of 3-dimensional manifolds with parametrized boundary, satisfying some additional conditions, to an algebraic-combinatorial category. It is built together with its truncations with respect to a natural grading, and we prove that these TQFTs are non-degenerate and anomaly-free. The TQFT(s) induce(s) a (series of) representation(s) of a subgroup ${\cal L}_g$ of the Mapping Class Group that contains the Torelli group. The N=1 truncation produces a TQFT for the Casson-Walker-Lescop invariant.Comment: 28 pages, 13 postscript figures. Version 2 (Section 1 has been considerably shorten, and section 3 has been slightly shorten, since they will constitute a separate paper. Section 4, which contained only announce of results, has been suprimated; it will appear in detail elsewhere. Consequently some statements have been re-numbered. No mathematical changes have been made.

A new species of Chaunus from Central Brazil : Anura; Bufonidae

A new species of Chaunus, apparently related to Chaunus arenarum, Chaunus rubescens, and Chaunus achavali is described. The new species occupies Cerrado habitats in southwestern Piauı´ and Bahia states and in northwestern Minas Gerais state, Brazil. The species is characterized by anterior interruption of the supraocular crest; weakly developed cranial crests; short and robust limbs; several pointed spiculae on dorsum, head, and limbs; male coloration; small to medium size; and by the short and narrow head