Genetic influences on the migration of cerebellar granule cells and on the development of cerebellar folia

A comparison of the cerebellar cortex of BALB/cByJ and C57BL/6J mice showed two morphological differences. First, the BALB/cByJ progenitor strain have a high number of ectopic granule cells (145.8 ± 8.7 per section), whereas the C57BL/6J progenitor strain have a low number (36.0 ± 1.0 per section). Second, BALB/cByJ mice have a secondary fissure which subdivides the uvulovermal lobule. The CXB set of recombinant inbred strains, originally derived using BALB/c and C57BL/6 as progenitor strains, was used to determine the genetic influences on the production of ectopic granule cells and on cerebellar foliation and to determine their relationship to each other. Of the seven recombinant inbred strains, five (CXBD, CXBG, CXBH, CXBI, and CXBK) have BALB/c-like numbers of ectopic granule cells and two (CXBE and CXBJ) had C57BL/6-like numbers of ectopic granule cells. Small clusters of ectopic granule cells located at the pial surface are found in BALB/cByJ and in all five of the recombinant inbred strains with BALB/c-like granule cell ectopia. The fact that the strain distribution patterns for both the granule cell ectopia and the presence of small ectopic granule cell clusters are concordantwith the strain distribution pattern for the Hid locus, a single autosomal dominant gene that affects the lamination of hippocampal area CA3c, indicate thatHW has pleiotropic effects on both cerebellar and hippocampal development. The strain distribution pattern for the presence of the secondary fissure in the uvulovermal lobule is non-concordant with the strain distribution pattern for the Hid locus. In addition, secondary fissures not characteristic of either progenitor strain are found in some of the CXB strains, and two recombinant inbred strains (CXBD and CXBG) have large clusters of ectopic granule cells and ectopic Purkinje cells. Thus, this study has identified three different aspects of cerebellar development that are under distinct genetic control: 1) the presence of ectopic granule cells and small clusters of ectopic granule cells, both of which may be pleiotropic effects ofHid, 2) the presence of large clusters of ectopic granule cells and ectopic Purkinje cells, and 3) the pattern of cerebellar foliation. These findings demonstrate that inbred and recombinant inbred strains are useful for the elucidation of developmental genetic relationships between diverse regions of the CNS

Undesirable social relations as risk factors for loneliness among 14-year-olds in the UK: Findings from the Millennium Cohort Study

In the current study, data collected from Wave 6 of the Millennium Cohort Study (n = 11,872), a nationally representative sample survey of youth aged 14 years in the UK, are used to examine the prevalence of loneliness among this age-group, investigate the feelings associated with the experience of loneliness among youth, explore the risk factors for loneliness among young people, and learn how they coped with loneliness. Given recent findings that youth are vulnerable to loneliness, the study assesses the prevalence of loneliness among adolescents across some important sociodemographic characteristics, such as nation of residence, gender, and ethnicity. We also identify the kinds of social experiences that accompany loneliness during adolescence, exploring friendship, relations with parents, social support, and bullying. Our key finding is that, in addition to the absence of desired social relationships, which has been typically identified as the ultimate source of loneliness, the presence of undesirable and even harmful social relationships is a major source of loneliness. This study uniquely brings together psychological and sociological perspectives to understand the experience of youth loneliness

Undesirable social relations as risk factors for loneliness among 14-year-olds in the UK : findings from the Millennium Cohort Study.

In the current study, data collected from Wave 6 of the Millennium Cohort Study (n = 11,872), a nationally representative sample survey of youth aged 14 years in the UK, are used to examine the prevalence of loneliness among this age-group, investigate the feelings associated with the experience of loneliness among youth, explore the risk factors for loneliness among young people, and learn how they coped with loneliness. Given recent findings that youth are vulnerable to loneliness, the study assesses the prevalence of loneliness among adolescents across some important sociodemographic characteristics, such as nation of residence, gender, and ethnicity. We also identify the kinds of social experiences that accompany loneliness during adolescence, exploring friendship, relations with parents, social support, and bullying. Our key finding is that, in addition to the absence of desired social relationships, which has been typically identified as the ultimate source of loneliness, the presence of undesirable and even harmful social relationships is a major source of loneliness. This study uniquely brings together psychological and sociological perspectives to understand the experience of youth loneliness

Obtaining the nuclear gluon distribution from heavy quark decays to lepton pairs in pAA collisions

We have studied how lepton pairs from decays of heavy-flavoured mesons produced in p$A$ collisions can be used to determine the modifications of the gluon distribution in the nucleus. Since heavy quark production is dominated by the $gg$ channel, the ratio of correlated lepton pair cross sections from $D\bar D$ and $B\bar B$ decays in p$A$ and pp collisions directly reflects the ratio $R_g^A \equiv f_g^A/f_g^p$. We have numerically calculated the lepton pair cross sections from these decays in pp and p$A$ collisions at SPS, RHIC and LHC energies. We find that ratio of the p$A$ to pp cross sections agrees quite well with the input $R_g^A.$ Thus, sufficiently accurate measurements could be used to determine the nuclear modification of the gluon distribution over a greater range of $x$ and $Q^2$ than presently available, putting strong constraints on models.Comment: 19 pages, 6 figure

Astroparticle Physics with a Customized Low-Background Broad Energy Germanium Detector

The MAJORANA Collaboration is building the MAJORANA DEMONSTRATOR, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The MAJORANA DEMONSTRATOR will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/c^2 mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the MAJORANA Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.Comment: Submitted to NIMA Proceedings, SORMA XII. 9 pages, 4 figure

MicroRNAs are deeply linked to the emergence of the complex octopus brain

Soft-bodied cephalopods such as octopuses are exceptionally intelligent invertebrates with a highly complex nervous system that evolved independently from vertebrates. Because of elevated RNA editing in their nervous tissues, we hypothesized that RNA regulation may play a major role in the cognitive success of this group. We thus profiled messenger RNAs and small RNAs in three cephalopod species including 18 tissues of the (Octopus vulgaris). We show that the major RNA innovation of soft-bodied cephalopods is an expansion of the microRNA (miRNA) gene repertoire. These evolutionarily novel miRNAs were primarily expressed in adult neuronal tissues and during the development and had conserved and thus likely functional target sites. The only comparable miRNA expansions happened, notably, in vertebrates. Thus, we propose that miRNAs are intimately linked to the evolution of complex animal brains

Temporal, spatial, and structural patterns of adult trembling aspen and white spruce mortality in Quebec's boreal forest

Temporal, spatial, and structural patterns of adult trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) mortality were studied in intact 150-year-old stands in the southwestern boreal forest of Quebec. For both species, mortality decreases (number of dead trees/total number of trees) with distance from the lake edge until 100-150 m, from which point it slightly increases. Strong peaks in mortality were found for 40- to 60-year-old aspen mainly between 1974 and 1992. Such mortality in relatively young aspen is likely related to competition for light from the dominant canopy trees. Also, the recruitment of this young aspen cohort is presumably the result of a stand breakup that occurred when the initial aspen-dominated stand was between 90 and 110 years old. For spruce, strong peaks in mortality were found in 110- to 150-year-old trees and they occurred mainly after 1980. No clear explanation could be found for these peaks, but we suggest that they may be related to senescence or weakening of the trees following the last spruce budworm outbreak. Suppressed and codominant aspen had a much higher mortality ratio than spruce in the same height class, while more surprisingly, no difference in mortality rate was found between dominant trees of the two species. Most spruce trees were found as standing dead, which leads us to reject the hypothesis that windthrow is an important cause of mortality for spruce in our forests

Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

Measurement of Rb in e+e- Collisions at 182 - 209 GeV

Measurements of Rb, the ratio of the bbbar cross-section to the qqbar cross- section in e+e- collisions, are presented. The data were collected by the OPAL experiment at LEP at centre-of-mass energies between 182 GeV and 209 GeV. Lepton, lifetime and event shape information is used to tag events containing b quarks with high efficiency. The data are compatible with the Standard Model expectation. The mean ratio of the eight measurements reported here to the Standard Model prediction is 1.055+-0.031+-0.037, where the first error is statistical and the second systematic.Comment: 21 pages, 5 figures, Submitted to Phys. Letts

Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays

The lifetime and oscillation frequency of the B0 meson has been measured using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP. The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the production flavour of the B0 mesons was determined using a combination of tags from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d = 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.