The ultraviolet spectrum of HH 24A and its relation to optical spectra

The spectrum of the brightest part (HH 24A) of the complex Herbig-Haro object HH 24 in the short wavelength UV range was studied. The object is of special interest since it is known that in the optical range the continuum is due to dust scattered light originating in a young stellar object while the shock excited emission lines are formed in HH 24A itself. The spectrum shows only a continuum or a quasi-continuum and is not comparable to that of the typical high excitation object like HH1 or HH2 nor to that of a low excitation object like HH3 or HH47

Probing halo nucleus structure through intermediate energy elastic scattering

This work addresses the question of precisely what features of few body models of halo nuclei are probed by elastic scattering on protons at high centre-of-mass energies. Our treatment is based on a multiple scattering expansion of the proton-projectile transition amplitude in a form which is well adapted to the weakly bound cluster picture of halo nuclei. In the specific case of $^{11}$Li scattering from protons at 800 MeV/u we show that because core recoil effects are significant, scattering crosssections can not, in general, be deduced from knowledge of the total matter density alone. We advocate that the optical potential concept for the scattering of halo nuclei on protons should be avoided and that the multiple scattering series for the full transition amplitude should be used instead.Comment: 8 pages REVTeX, 1 eps figure, accepted for publication in Phys. Rev.

Magnetic and superconducting phase diagrams in ErNi2B2C

We present measurements of the superconducting upper critical field Hc2(T) and the magnetic phase diagram of the superconductor ErNi2B2C made with a scanning tunneling microscope (STM). The magnetic field was applied in the basal plane of the tetragonal crystal structure. We have found large gapless regions in the superconducting phase diagram of ErNi2B2C, extending between different magnetic transitions. A close correlation between magnetic transitions and Hc2(T) is found, showing that superconductivity is strongly linked to magnetism.Comment: 5 pages, 4 figure

Trade protectionism and intra-industry trade: a USA - EU comparison

The aim of this work is to find patterns for products included in the customs tariffs of the USA and the EU (composed of over 5000 products disaggregated at the 6 digit-level) which share similarities, defined by a set of international trade variables, namely the index of revealed comparative advantages (RCA), the Grubel-Lloyd index, and other indicators of international trade. There is a strand in the literature advancing a theory that links the degree of intra-industry trade with the level of protectionism. In order to test this theory we use cluster analysis as a method of data analysis and the Grubel-Lloyd index as a classification variable between groups. For each of the analyzed regions we obtain four different groups. Thereafter each of these four clusters are further characterized with the help of the other international trade indicators and the tariffs. Finally, we establish a comparison between the two regions by examining possible differences and similarities. The results show a significant difference in the tariffs applied between the USA and the EU, with the USA presenting a lower level of protectionism. Additionally, the results for the USA show a positive relationship between the degree of intra-industry trade and a lower level of protectionism, while for the EU the results are not conclusive.info:eu-repo/semantics/publishedVersio

Proper Motions of Young Stellar Outflows in the Mid-infrared with Spitzer (IRAC). I. The NGC 1333 Region

We use two 4.5 μm Spitzer (IRAC) maps of the NGC 1333 region taken over a ~7 yr interval to determine proper motions of its associated outflows. This is a first successful attempt at obtaining proper motions of stellars' outflow from Spitzer observations. For the outflow formed by the Herbig-Haro objects HH7, 8, and 10, we find proper motions of ~9-13 km s–1, which are consistent with previously determined optical proper motions of these objects. We determine proper motions for a total of eight outflows, ranging from ~10 to 100 km s–1. The derived proper motions show that out of these eight outflows, three have tangential velocities ≤20 km s–1. This result shows that a large fraction of the observed outflows have low intrinsic velocities and that the low proper motions are not merely a projection effect

Direct carrier–envelope phase stabilization of a soliton-effect compressed sub-two-cycle pulse source through nonlinear mixing of solitonic and dispersive waves

We present a carrier–envelope phase (CEP) stabilized sub-two-cycle 5.2 fs pulse source based on soliton-effect self-compression of femtosecond laser pulses in millimetre-long highly nonlinear photonic crystal fibres. We employ a simple and efficient scheme to generate a strong (40–60 dB, configuration dependent) CEP beat signal directly from the pulse source via f-to-2f interferometry where the second harmonic of the main soliton pulse is mixed with the isolated dispersive blue/green radiation peak that is also generated in the compression process, obviating the need for additional spectral broadening mechanisms.Fundação para a Ciência e a Tecnologia (Portugal)Fonds Europeen de Developpement Economique et Regional (Grant PTDC/FIS/115102/2009