Prefrontal Activity Links Nonoverlapping Events in Memory

The medial prefrontal cortex (mPFC) plays an important role in memory. By maintaining a working memory buffer, neurons in prelimbic (PL) mPFC may selectively contribute to learning associations between stimuli that are separated in time, as in trace fear conditioning (TFC). Until now, evidence for this bridging role was largely descriptive. Here we used optogenetics to silence neurons in the PL mPFC of rats during learning in TFC. Memory formation was prevented when mPFC was silenced specifically during the interval separating the cue and shock. Our results provide support for a working memory function for these cells and indicate that associating two noncontiguous stimuli requires bridging activity in PL mPFC

Density and kinematics of the W49A cloud core

The dense core of the W49A molecular cloud (Miyawaki et al. 1986, Schloerb et al. 1987) has been mapped in 5 different transitions of CS and C^(34)S, in order to determine its density structure. The three lower frequency transitions (CS J=3-2, CS J=5-4 and C^(34)S J=5-4) were observed with the IRAM 30m telescope, and the two highest frequency transitions (CS J=7-6 and C^(34)S J=7-6) with the Caltech Submillimeter Observatory. The beamsizes were in the range 12″ to 20″. As a calibration check, the CS J=7-6 line was observed with both telescopes, and was found to give a consistent temperature scale. The spectra at the peak of the emission are shown in Fig. 1

IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 53

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Three-dimensional bulk band dispersion in polar BiTeI with giant Rashba-type spin splitting

In layered polar semiconductor BiTeI, giant Rashba-type spin-split band dispersions show up due to the crystal structure asymmetry and the strong spin-orbit interaction. Here we investigate the 3-dimensional (3D) bulk band structures of BiTeI using the bulk-sensitive $h\nu$-dependent soft x-ray angle resolved photoemission spectroscopy (SX-ARPES). The obtained band structure is shown to be well reproducible by the first-principles calculations, with huge spin splittings of ${\sim}300$ meV at the conduction-band-minimum and valence-band-maximum located in the $k_z=\pi/c$ plane. It provides the first direct experimental evidence of the 3D Rashba-type spin splitting in a bulk compound.Comment: 9 pages, 4 figure

Raman and fluorescence contributions to resonant inelastic soft x-ray scattering on LaAlO3_3/SrTiO3_3 heterostructures

We present a detailed study of the Ti 3$d$ carriers at the interface of LaAlO$_3$/SrTiO$_3$ heterostructures by high-resolution resonant inelastic soft x-ray scattering (RIXS), with special focus on the roles of overlayer thickness and oxygen vacancies. Our measurements show the existence of interfacial Ti 3$d$ electrons already below the critical thickness for conductivity and an increase of the total interface charge up to a LaAlO$_3$ overlayer thickness of 6 unit cells before it levels out. By comparing stoichiometric and oxygen deficient samples we observe strong Ti 3$d$ charge carrier doping by oxygen vacancies. The RIXS data combined with photoelectron spectroscopy and transport measurements indicate the simultaneous presence of localized and itinerant charge carriers. However, it is demonstrated that the relative amount of localized and itinerant Ti $3d$ electrons in the ground state cannot be deduced from the relative intensities of the Raman and fluorescence peaks in excitation energy dependent RIXS measurements, in contrast to previous interpretations. Rather, we attribute the observation of either the Raman or the fluorescence signal to the spatial extension of the intermediate state reached in the RIXS excitation process.Comment: 9 pages, 6 figure

Suzaku Observation of Two Ultraluminous X-Ray Sources in NGC 1313

Two ultraluminous X-ray sources (ULXs) in the nearby Sb galaxy NGC 1313, named X-1 and X-2, were observed with Suzaku on 2005 September 15. During the observation for a net exposure of 28~ks (but over a gross time span of 90~ks), both objects varied in intensity by about 50~%. The 0.4--10 keV X-ray luminosity of X-1 and X-2 was measured as $2.5 \times 10^{40}~{\rm erg~s^{-1}}$ and $5.8 \times 10^{39}~{\rm erg~s^{-1}}$, respectively, with the former the highest ever reported for this ULX. The spectrum of X-1 can be explained by a sum of a strong and variable power-law component with a high energy cutoff, and a stable multicolor blackbody with an innermost disk temperature of $\sim 0.2$ keV. These results suggest that X-1 was in a ``very high'' state, where the disk emission is strongly Comptonized. The absorber within NGC 1313 toward X-1 is suggested to have a subsolar oxygen abundance. The spectrum of X-2 is best represented, in its fainter phase, by a multicolor blackbody model with the innermost disk temperature of 1.2--1.3 keV, and becomes flatter as the source becomes brighter. Hence X-2 is interpreted to be in a slim-disk state. These results suggest that the two ULXs have black hole masses of a few tens to a few hundreds solar masses.Comment: accepted for publication in PAS

CNMNC guidelines for the nomenclature of polymorphs and polysomes

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