High-spin structure and Band Termination in 103^{103}Cd

Excited states of the neutron deficient $^{103}$Cd nucleus have been investigated via the $^{72}$Ge($^{35}$Cl, p3n) reaction at beam energy of 135 MeV by use of in-beam spectroscopic methods. Gamma rays depopulating the excited states were detected using the Gammasphere spectrometer with high-fold $\gamma$-ray coincidences. A quadrupole $\gamma$-ray coincidence analysis ($\gamma^{4}$) has been used to extend the known level scheme. The positive parity levels have been established up to $J = 35/2\hbar$ and $E_{x} = 7.071$ MeV. In addition to the observation of highly-fragmented level scheme belonging to the positive-parity sequences at E$_{x}\sim$ 5 MeV, the termination of a negative-parity sequence connected by $E2$ transitions has been established at $J = 47/2 \hbar$ and $E_{x} = 11.877$ MeV. The experimental results corresponding to both the positive- and negative-parity sequences have been theoretically interpreted in the framework of the core particle coupling model. Evidence is presented for a shape change from collective prolate to non-collective oblate above the $J^{\pi} = 39/2^{-}$ (8011 keV) level and for a smooth termination of the negative-parity band.Comment: 19 pages, 8 figures. Submitted to Phys. Rev.

High-spin structure and Band Termination in 103^{103}Cd

Excited states of the neutron deficient $^{103}$Cd nucleus have been investigated via the $^{72}$Ge($^{35}$Cl, p3n) reaction at beam energy of 135 MeV by use of in-beam spectroscopic methods. Gamma rays depopulating the excited states were detected using the Gammasphere spectrometer with high-fold $\gamma$-ray coincidences. A quadrupole $\gamma$-ray coincidence analysis ($\gamma^{4}$) has been used to extend the known level scheme. The positive parity levels have been established up to $J = 35/2\hbar$ and $E_{x} = 7.071$ MeV. In addition to the observation of highly-fragmented level scheme belonging to the positive-parity sequences at E$_{x}\sim$ 5 MeV, the termination of a negative-parity sequence connected by $E2$ transitions has been established at $J = 47/2 \hbar$ and $E_{x} = 11.877$ MeV. The experimental results corresponding to both the positive- and negative-parity sequences have been theoretically interpreted in the framework of the core particle coupling model. Evidence is presented for a shape change from collective prolate to non-collective oblate above the $J^{\pi} = 39/2^{-}$ (8011 keV) level and for a smooth termination of the negative-parity band.Comment: 19 pages, 8 figures. Submitted to Phys. Rev.

A Composite Chiral Pair of Rotational Bands in the odd-A Nucleus 135Nd

High-spin states in 135Nd were populated with the 110Pd(30Si,5n)135Nd reaction at a 30Si bombarding energy of 133 MeV. Two Delta(I)=1 bands with close excitation energies and the same parity were observed. These bands are directly linked by Delta(I)=1 and Delta(I)=2 transitions. The chiral nature of these two bands is confirmed by comparison with three-dimensional tilted axis cranking calculations. This is the first observation of a three-quasiparticle chiral structure and established the primarily geometric nature of this phenomenon.Comment: 10 pages, 5 figures (1 in color), 1 table, submitted to Physics Review Letters, written in REVTEX4 forma

Lifetime measurements of Triaxial Strongly Deformed bands in 163^{163}Tm

With the Doppler Shift Attenuation Method, quadrupole transition moments, $Q_t$, were determined for the two recently proposed Triaxial Strongly Deformed (TSD) bands in $^{163}$Tm. The measured $Q_t$ moments indicate that the deformation of these bands is larger than that of the yrast, signature partners. However, the measured values are smaller than those predicted by theory. This observation appears to be valid for TSD bands in several nuclei of the regionComment: 8 pages, 5 figures. Submitted to Physical Review

Level Structure of 103Ag at high spins

High spin states in $^{103}$Ag were investigated with the Gammasphere array, using the $^{72}$Ge($^{35}$Cl,$2p2n$)$^{103}$Ag reaction at an incident beam energy of 135 MeV. A $\Delta J$=1 sequence with predominantly magnetic transitions and two nearly-degenerate $\Delta J=1$ doublet bands have been observed. The dipole band shows a decreasing trend in the $B(M1)$ strength as function of spin, a well established feature of magnetic bands. The nearly-degenerate band structures satisfy the three experimental signatures of chirality in the nuclei; however microscopic calculations are indicative of a magnetic phenomeno

Low Temperature Transport and Specific Heat Studies of Nd_{1-x}Pb_{x}MnO_{3} Single Crystals

Electrical transport and specific heat properties of Nd_{1-x}Pb_{x}MnO_{3} single crystals for 0.15 < x 0.5 have been studied in low temperature regime. The resistivity in the ferromagnetic insulating (FMI) phase for x < 0.3 has an activated character. The dependence of the activation gap Delta on doping x has been determined and the critical concentration for the zero-temperature metal-insulator transition was determined as x_{c} ~ 0.33. For a metallic sample with x=0.42, a conventional electron-electron (e-e) scattering term proportional T^{2} is found in the low-temperature electrical resistivity, although the Kadowaki-Woods ratio is found to be much larger for this manganite than for a normal metal. For a metallic sample with x=0.5, a resistivity minimum is observed for x= 0.5. The effect is attributed to weak localization and can be described by a negative T^{1/2} weak-localization contribution to resistivity for a disordered three-dimensional electron system. The specific heat data have been fitted to contributions from free electrons (gamma), spin excitations (beta_{3/2}), lattice and a Schottky-like anomaly related to the rare-earth magnetism of the Nd ions. The value of gamma is larger than for normal metals, which is ascribed to magnetic ordering effects involving Nd. Also, the Schottky-like anomaly appears broadened and weakened suggesting inhomogeneous molecular fields at the Nd-sites.Comment: 14 pages, 8 figure

Transcriptional Regulation of Enhancers Active in Protodomains of the Developing Cerebral Cortex

SummaryElucidating the genetic control of cerebral cortical (pallial) development is essential for understanding function, evolution, and disorders of the brain. Transcription factors (TFs) that embryonically regulate pallial regionalization are expressed in gradients, raising the question of how discrete domains are generated. We provide evidence that small enhancer elements active in protodomains integrate broad transcriptional information. CreERT2 and GFP expression from 14 different enhancer elements in stable transgenic mice allowed us to define a comprehensive regional fate map of the pallium. We explored transcriptional mechanisms that control the activity of the enhancers using informatics, in vivo occupancy by TFs that regulate cortical patterning (CoupTFI, Pax6, and Pbx1), and analysis of enhancer activity in Pax6 mutants. Overall, the results provide insights into how broadly expressed patterning TFs regulate the activity of small enhancer elements that drive gene expression in pallial protodomains that fate map to distinct cortical regions

Aberrant chromatin landscape following loss of the H3.3 chaperone Daxx in haematopoietic precursors leads to Pu.1-mediated neutrophilia and inflammation

Defective silencing of retrotransposable elements has been linked to inflammageing, cancer and autoimmune diseases. However, the underlying mechanisms are only partially understood. Here we implicate the histone H3.3 chaperone Daxx, a retrotransposable element repressor inactivated in myeloid leukaemia and other neoplasms, in protection from inflammatory disease. Loss of Daxx alters the chromatin landscape, H3.3 distribution and histone marks of haematopoietic progenitors, leading to engagement of a Pu.1-dependent transcriptional programme for myelopoiesis at the expense of B-cell differentiation. This causes neutrophilia and inflammation, predisposing mice to develop an autoinflammatory skin disease. While these molecular and phenotypic perturbations are in part reverted in animals lacking both Pu.1 and Daxx, haematopoietic progenitors in these mice show unique chromatin and transcriptome alterations, suggesting an interaction between these two pathways. Overall, our findings implicate retrotransposable element silencing in haematopoiesis and suggest a cross-talk between the H3.3 loading machinery and the pioneer transcription factor Pu.1

Coding potential of the products of alternative splicing in human

Background: Analysis of the human genome has revealed that as much as an order of magnitude more of the genomic sequence is transcribed than accounted for by the predicted and characterized genes. A number of these transcripts are alternatively spliced forms of known protein coding genes; however, it is becoming clear that many of them do not necessarily correspond to a functional protein. Results: In this study we analyze alternative splicing isoforms of human gene products that are unambiguously identified by mass spectrometry and compare their properties with those of isoforms of the same genes for which no peptide was found in publicly available mass spectrometry datasets. We analyze them in detail for the presence of uninterrupted functional domains, active sites as well as the plausibility of their predicted structure. We report how well each of these strategies and their combination can correctly identify translated isoforms and derive a lower limit for their specificity, that is, their ability to correctly identify non-translated products. Conclusions: The most effective strategy for correctly identifying translated products relies on the conservation of active sites, but it can only be applied to a small fraction of isoforms, while a reasonably high coverage, sensitivity and specificity can be achieved by analyzing the presence of non-truncated functional domains. Combining the latter with an assessment of the plausibility of the modeled structure of the isoform increases both coverage and specificity with a moderate cost in terms of sensitivity