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

Out-of-plane nesting driven spin spiral in ultrathin Fe/Cu(001) films

Epitaxial ultrathin Fe films on fcc Cu(001) exhibit a spin spiral (SS), in contrast to the ferromagnetism of bulk bcc Fe. We study the in-plane and out-of-plane Fermi surfaces (FSs) of the SS in 8 monolayer Fe/Cu(001) films using energy dependent soft x-ray momentum-resolved photoemission spectroscopy. We show that the SS originates in nested regions confined to out-of-plane FSs, which are drastically modified compared to in-plane FSs. From precise reciprocal space maps in successive zones, we obtain the associated real space compressive strain of 1.5+-0.5% along c-axis. An autocorrelation analysis quantifies the incommensurate ordering vector q=(2pi/a)(0,0,~0.86), favoring a SS and consistent with magneto-optic Kerr effect experiments. The results reveal the importance of in-plane and out-of-plane FS mapping for ultrathin films.Comment: 4 pages, 3 figure

Relationships between Social Spending and Childhood Obesity in OECD Countries:An Ecological Study

Objectives The burden of childhood obesity is clustered among children in low-socioeconomic groups. Social spending on children—public welfare expenditure on families and education—may curb childhood obesity by reducing socioeconomic disadvantages. The objective of this study was to examine the relationship between social spending on children and childhood obesity across the Organisation for Economic Cooperation and Development (OECD) countries. Design Ecological study. Setting Data on social spending on children were obtained from the OECD Social Expenditure Database and the OECD educational finance indicators dataset during 2000–2015. Data on childhood obesity were obtained from the NCD Risk Factor Collaboration database. Participants Aggregated statistics on obesity among children aged 5–19 years, estimated for OECD 35 countries based on the measured height and weight on 31.5 million children. Outcome measures Country-level prevalence of obesity among children aged 5–19 years. Results In cross-sectional analyses in 2015, social spending on children was inversely associated with the prevalence of childhood obesity after adjusting for potential confounders (the gross domestic product per capita, unemployment rate, poverty rate, percentage of children aged <20 years and prevalence of childhood obesity in 2000). In addition, when we focused on changes from 2000 to 2015, an average annual increase of US$100 in social spending per child was associated with a decrease in childhood obesity by 0.6 percentage points for girls (p=0.007) and 0.7 percentage points for boys (p=0.04) between 2000 and 2015, after adjusting for the potential confounders. The dimensions of social spending that contributed to these associations between the changes in social spending on children and childhood obesity were early childhood education and care (ECEC) and school education for girls and ECEC for boys. Conclusion Countries that increase social spending on children tend to experience smaller increases in childhood obesit

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

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

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On higher congruences between cusp forms and Eisenstein series

In this paper we present several finite families of congruences between cusp forms and Eisenstein series of higher weights at powers of prime ideals. We formulate a conjecture which describes properties of the prime ideals and their relation to the weights. We check the validity of the conjecture on several numerical examples.Comment: 20 page

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