Long-time tails and cage effect in driven granular fluids

We study the velocity autocorrelation function (VACF) of a driven granular fluid in the stationary state in 3 dimensions. As the critical volume fraction of the glass transition in the corresponding elastic system is approached, we observe pronounced cage effects in the VACF as well as a strong decrease of the diffusion constant. At moderate densities the VACF is shown to decay algebraically in time (t^{-3/2}) like in a molecular fluid, as long as the driving conserves momentum locally.Comment: 4 pages, 4 figure

Level densities and γ\gamma-strength functions in 148,149^{148,149}Sm

The level densities and $\gamma$-strength functions of the weakly deformed $^{148}$Sm and $^{149}$Sm nuclei have been extracted. The temperature versus excitation energy curve, derived within the framework of the micro canonical ensemble, shows structures, which we associate with the break up of Cooper pairs. The nuclear heat capacity is deduced within the framework of both the micro canonical and the canonical ensemble. We observe negative heat capacity in the micro canonical ensemble whereas the canonical heat capacity exhibits an S-shape as function of temperature, both signals of a phase transition. The structures in the $\gamma$-strength functions are discussed in terms of the pygmy resonance and the scissors mode built on exited states. The samarium results are compared with data for the well deformed $^{161,162}$Dy, $^{166,167}$Er and $^{171,172}$Yb isotopes and with data from (n,$\gamma$)-experiments and giant dipole resonance studies.Comment: 12 figure

Thermal and electromagnetic properties of 166-Er and 167-Er

The primary gamma-ray spectra of 166-Er and 167-Er are deduced from the (3-He,alpha gamma) and (3-He,3-He' gamma) reaction, respectively, enabling a simultaneous extraction of the level density and the gamma-ray strength function. Entropy, temperature and heat capacity are deduced from the level density within the micro-canonical and the canonical ensemble, displaying signals of a phase-like transition from the pair-correlated ground state to an uncorrelated state at Tc=0.5 MeV. The gamma-ray strength function displays a bump around E-gamma=3 MeV, interpreted as the pygmy resonance.Comment: 21 pages including 2 tables and 11 figure

Gamma-ray strength function and pygmy resonance in rare earth nuclei

The gamma-ray strength function for gamma energies in the 1-7 MeV region has been measured for 161,162-Dy and 171,172-Yb using the (3-He,alpha gamma) reaction. Various models are tested against the observed gamma-ray strength functions. The best description is based on the Kadmenskii, Markushev and Furman E1 model with constant temperature and the Lorentzian M1 model. A gamma-ray bump observed at E_gamma=3 MeV is interpreted as the so-called pygmy resonance, which has also been observed previously in (n,gamma) experiments. The parameters for this resonance have been determined and compared to the available systematics.Comment: 11 pages, including 4 figures and 2 table

Disentangling nature from nurture in examining the interplay between parent–child relationships, ADHD, and early academic attainment

Background: Attention Deficit Hyperactivity Disorder (ADHD) is highly heritable and is associated with lower educational attainment. ADHD is linked to family adversity, including hostile parenting. Questions remain regarding the role of genetic and environmental factors underlying processes through which ADHD symptoms develop and influence academic attainment. Method: This study employed a parent-offspring adoption design (N=345) to examine the interplay between genetic susceptibility to child attention problems (birth mother ADHD symptoms) and adoptive parent (mother and father) hostility on child lower academic outcomes, via child ADHD symptoms. Questionnaires assessed birth mother ADHD symptoms, adoptive parent (mother and father) hostility to child, early child impulsivity/activation, and child ADHD symptoms. The Woodcock-Johnson test was used to examine child reading and math aptitude. Results: Building on a previous study (Harold et al., 2013), heritable influences were found: birth mother ADHD symptoms predicted child impulsivity/activation. In turn, child impulsivity/activation (4.5 years) evoked maternal and paternal hostility, which was associated with children’s ADHD continuity (6 years). Both maternal and paternal hostility (4.5 years) contributed to impairments in math but not reading (7 years), via impacts on ADHD symptoms (6 years). Conclusion: Findings highlight the importance of early child behavior dysregulation evoking parent hostility in both mothers and fathers, with maternal and paternal hostility contributing to the continuation of ADHD symptoms and lower levels of later math ability. Early interventions may be important for the promotion of child math skills in those with ADHD symptoms, especially where children have high levels of early behavior dysregulation

Level density and thermal properties in rare earth nuclei

A convergent method to extract the nuclear level density and the gamma-ray strength function from primary gamma-ray spectra has been established. Thermodynamical quantities have been obtained within the microcanonical and canonical ensemble theory. Structures in the caloric curve and in the heat capacity curve are interpreted as fingerprints of breaking of Cooper pairs and quenching of pairing correlations. The strength function can be described using models and common parameterizations for the E1, M1 and pygmy resonance strength. However, a significant decrease of the pygmy resonance strength at finite temperatures has been observed.Comment: 15 pages including 8 figures. Proceedings article for the conference Nuclear Structure and Related Topics, Dubna, Russia, June 6-10, 200

Non-relativistic metrics from back-reacting fermions

It has recently been pointed out that under certain circumstances the back-reaction of charged, massive Dirac fermions causes important modifications to AdS_2 spacetimes arising as the near horizon geometry of extremal black holes. In a WKB approximation, the modified geometry becomes a non-relativistic Lifshitz spacetime. In three dimensions, it is known that integrating out charged, massive fermions gives rise to gravitational and Maxwell Chern-Simons terms. We show that Schrodinger (warped AdS_3) spacetimes exist as solutions to a gravitational and Maxwell Chern-Simons theory with a cosmological constant. Motivated by this, we look for warped AdS_3 or Schrodinger metrics as exact solutions to a fully back-reacted theory containing Dirac fermions in three and four dimensions. We work out the dynamical exponent in terms of the fermion mass and generalize this result to arbitrary dimensions.Comment: 26 pages, v2: typos corrected, references added, minor change

Stunting is preceded by intestinal mucosal damage and microbiome changes and Is associated with systemic inflammation in a cohort of Peruvian infants

Stunting, defined as height-for-ag

Identification of Small Molecule Lead Compounds for Visceral Leishmaniasis Using a Novel Ex Vivo Splenic Explant Model System

Visceral leishmaniasis is a life threatening parasitic disease present in several countries of the world. New drugs are needed to treat this disease because treatments are becoming increasingly ineffective. We established a novel system to screen for new anti-leishmanial compounds that utilizes spleen cells from hamsters infected with the parasite Leishmania donovani. The parasite strain we used was genetically engineered to emit light by the incorporation of the firefly luciferase gen. This laboratory test system has the advantage of reproducing the cellular environment where the drug has to combat the infection. The efficacy of the compounds is easily determined by measuring the light emitted by the surviving parasites in a luminometer after exposing the infected cells to the test compounds. The screening of more than 4,000 molecules showed that 84 (2.1%) of them showed anti-leishmanial activity and had an acceptable toxicity evaluation. Eighty two percent of these molecules, which had varied chemical structures, were previously unknown to have anti-leishmanial activity. Further studies in animals of these new chemical entities may identify drug candidates for the treatment of visceral leishmaniasis

Pairing in nuclear systems: from neutron stars to finite nuclei

We discuss several pairing-related phenomena in nuclear systems, ranging from superfluidity in neutron stars to the gradual breaking of pairs in finite nuclei. We focus on the links between many-body pairing as it evolves from the underlying nucleon-nucleon interaction and the eventual experimental and theoretical manifestations of superfluidity in infinite nuclear matter and of pairing in finite nuclei. We analyse the nature of pair correlations in nuclei and their potential impact on nuclear structure experiments. We also describe recent experimental evidence that points to a relation between pairing and phase transitions (or transformations) in finite nuclear systems. Finally, we discuss recent investigations of ground-state properties of random two-body interactions where pairing plays little role although the interactions yield interesting nuclear properties such as 0+ ground states in even-even nuclei.Comment: 74 pages, 33 figs, uses revtex4. Submitted to Reviews of Modern Physic