174 research outputs found
Shape Coexistence in Pb186: Beyond-mean-field description by configuration mixing of symmetry restored wave functions
We study shape coexistence in Pb186 using configuration mixing of
angular-momentum and particle-number projected self-consistent mean-field
states. The same Skyrme interaction SLy6 is used everywhere in connection with
a density-dependent zero-range pairing force. The model predicts coexisting
spherical, prolate and oblate 0+ states at low energy.Comment: 5 pages REVTEX4, 4 eps figures, accepted by Phys. Lett. B. Revised
version with some polishing of the text without changing its conten
Moments of Inertia of Nuclei in the Rare Earth Region: A Relativistic versus Non-Relativistic Investigation
A parameter free investigation of the moments of inertia of ground state
rotational bands in well deformed rare-earth nuclei is carried out using
Cranked Relativistic Hartree-Bogoliubov (CRHB) and non-relativistic Cranked
Hartree-Fock-Bogoliubov (CHFB) theories. In CRHB theory, the relativistic
fields are determined by the non-linear Lagrangian with the NL1 force and the
pairing interaction by the central part of finite range Gogny D1S force. In
CHFB theory, the properties in particle-hole and particle-particle channels are
defined solely by Gogny D1S forces. Using an approximate particle number
projection before variation by means of the Lipkin Nogami method improves the
agreement with the experimental data, especially in CRHB theory. The effect of
the particle number projection on the moments of inertia and pairing energies
is larger in relativistic than in non-relativistic theory.Comment: 18 pages + 2 PostScript figure
Transcriptional correlates of the pathological phenotype in a Huntingtonβs disease mouse model
Huntington disease (HD) is a fatal neurodegenerative disorder without a cure that is caused by an
aberrant expansion of CAG repeats in exon 1 of the huntingtin (HTT) gene. Although a negative
correlation between the number of CAG repeats and the age of disease onset is established, additional
factors may contribute to the high heterogeneity of the complex manifestation of symptoms
among patients. This variability is also observed in mouse models, even under controlled genetic
and environmental conditions. To better understand this phenomenon, we analysed the R6/1 strain
in search of potential correlates between pathological motor/cognitive phenotypical traits and
transcriptional alterations. HD-related genes (e.g., Penk, Plk5, Itpka), despite being downregulated
across the examined brain areas (the prefrontal cortex, striatum, hippocampus and cerebellum),
exhibited tissue-specific correlations with particular phenotypical traits that were attributable to
the contribution of the brain region to that trait (e.g., striatum and rotarod performance, cerebellum
and feet clasping). Focusing on the striatum, we determined that the transcriptional dysregulation
associated with HD was partially exacerbated in mice that showed poor overall phenotypical scores,
especially in genes with relevant roles in striatal functioning (e.g., Pde10a, Drd1, Drd2, Ppp1r1b).
However, we also observed transcripts associated with relatively better outcomes, such as Nfya
(CCAAT-binding transcription factor NF-Y subunit A) plus others related to neuronal development,
apoptosis and differentiation. In this study, we demonstrated that altered brain transcription can be
related to the manifestation of HD-like symptoms in mouse models and that this can be extrapolated to
the highly heterogeneous population of HD patients
Mean field theory for global binding systematics
We review some possible improvements of mean field theory for application to
nuclear binding systematics. Up to now, microscopic theory has been less
successful than models starting from the liquid drop in describing accurately
the global binding systematics. We believe that there are good prospects to
develop a better global theory, using modern forms of energy density
functionals and treating correlation energies systematically by the RPA.Comment: RevTex, 17 pages, 5 eps figures. To be published in Yadernaya Fizika,
special edition for the 90th birthday of Professor A.B. Migda
Systematics of collective correlation energies from self-consistent mean-field calculations
The collective ground-state correlations stemming from low-lying quadrupole
excitations are computed microscopically. To that end, the self-consistent
mean-field model is employed on the basis of the Skyrme-Hartre-Fock (SHF)
functional augmented by BCS pairing. The microscopic-macroscopic mapping is
achieved by quadrupole-constrained mean-field calculations which are processed
further in the generator-coordinate method (GCM) at the level of the Gaussian
overlap approximation (GOA).
We study the correlation effects on energy, charge radii, and surface
thickness for a great variety of semi-magic nuclei. A key issue is to work out
the influence of variations of the SHF functional. We find that collective
ground-state correlations (GSC) are robust under change of nuclear bulk
properties (e.g., effective mass, symmetry energy) or of spin-orbit coupling.
Some dependence on the pairing strength is observed. This, however, does not
change the general conclusion that collective GSC obey a general pattern and
that their magnitudes are rather independent of the actual SHF parameters.Comment: 13 pages, 13 figure
Evaluating intelligent interfaces for post-editing automatic transcriptions of online video lectures
Video lectures are fast becoming an everyday educational resource in higher education. They are being incorporated into existing university curricula around the world, while also emerging as a key component of the open education movement. In 2007, the Universitat PolitΓ¨cnica de ValΓ¨ncia (UPV) implemented its poliMedia lecture capture system for the creation and publication of quality educational video content and now has a collection of over 10,000 video objects. In 2011, it embarked on the EU-subsidised transLectures project to add automatic subtitles to these videos in both Spanish and other languages. By doing so, it allows access to their educational content by non-native speakers and the deaf and hard-of-hearing, as well as enabling advanced repository management functions. In this paper, following a short introduction to poliMedia, transLectures and DocΓ¨ncia en Xarxa (Teaching Online), the UPV s action plan to boost the use of digital resources at the university, we will discuss the three-stage evaluation process carried out with the collaboration of UPV lecturers to find the best interaction protocol for the task of post-editing automatic subtitles.Valor MirΓ³, JD.; Spencer, RN.; PΓ©rez GonzΓ‘lez De Martos, AM.; GarcΓ©s DΓaz-MunΓo, GV.; TurrΓ³ Ribalta, C.; Civera Saiz, J.; Juan CΓscar, A. (2014). Evaluating intelligent interfaces for post-editing automatic transcriptions of online video lectures. Open Learning: The Journal of Open and Distance Learning. 29(1):72-85. doi:10.1080/02680513.2014.909722S7285291Fujii, A., Itou, K., & Ishikawa, T. (2006). LODEM: A system for on-demand video lectures. Speech Communication, 48(5), 516-531. doi:10.1016/j.specom.2005.08.006Gilbert, M., Knight, K., & Young, S. (2008). Spoken Language Technology [From the Guest Editors]. IEEE Signal Processing Magazine, 25(3), 15-16. doi:10.1109/msp.2008.918412Leggetter, C. J., & Woodland, P. C. (1995). Maximum likelihood linear regression for speaker adaptation of continuous density hidden Markov models. Computer Speech & Language, 9(2), 171-185. doi:10.1006/csla.1995.0010Proceedings of the 9th ACM SIGCHI New Zealand Chapterβs International Conference on Human-Computer Interaction Design Centered HCI - CHINZ β08. (2008). doi:10.1145/1496976Martinez-Villaronga, A., del Agua, M. A., Andres-Ferrer, J., & Juan, A. (2013). Language model adaptation for video lectures transcription. 2013 IEEE International Conference on Acoustics, Speech and Signal Processing. doi:10.1109/icassp.2013.6639314Munteanu, C., Baecker, R., & Penn, G. (2008). Collaborative editing for improved usefulness and usability of transcript-enhanced webcasts. Proceeding of the twenty-sixth annual CHI conference on Human factors in computing systems - CHI β08. doi:10.1145/1357054.1357117Repp, S., Gross, A., & Meinel, C. (2008). Browsing within Lecture Videos Based on the Chain Index of Speech Transcription. IEEE Transactions on Learning Technologies, 1(3), 145-156. doi:10.1109/tlt.2008.22Proceedings of the 2012 ACM international conference on Intelligent User Interfaces - IUI β12. (2012). doi:10.1145/2166966Serrano, N., GimΓ©nez, A., Civera, J., Sanchis, A., & Juan, A. (2013). Interactive handwriting recognition with limited user effort. International Journal on Document Analysis and Recognition (IJDAR), 17(1), 47-59. doi:10.1007/s10032-013-0204-5Torre Toledano, D., Ortega GimΓ©nez, A., Teixeira, A., GonzΓ‘lez RodrΓguez, J., HernΓ‘ndez GΓ³mez, L., San Segundo HernΓ‘ndez, R., & Ramos Castro, D. (Eds.). (2012). Advances in Speech and Language Technologies for Iberian Languages. Communications in Computer and Information Science. doi:10.1007/978-3-642-35292-8Wald, M. (2006). Creating accessible educational multimedia through editing automatic speech recognition captioning in real time. Interactive Technology and Smart Education, 3(2), 131-141. doi:10.1108/1741565068000005
Relativistic Nuclear Energy Density Functionals: Mean-Field and Beyond
Relativistic energy density functionals (EDF) have become a standard tool for
nuclear structure calculations, providing a complete and accurate, global
description of nuclear ground states and collective excitations. Guided by the
medium dependence of the microscopic nucleon self-energies in nuclear matter,
semi-empirical functionals have been adjusted to the nuclear matter equation of
state and to bulk properties of finite nuclei, and applied to studies of
arbitrarily heavy nuclei, exotic nuclei far from stability, and even systems at
the nucleon drip-lines. REDF-based structure models have also been developed
that go beyond the static mean-field approximation, and include collective
correlations related to the restoration of broken symmetries and to
fluctuations of collective variables. These models are employed in analyses of
structure phenomena related to shell evolution, including detailed predictions
of excitation spectra and electromagnetic transition rates.Comment: To be published in Progress in Particle and Nuclear Physic
Analysis of Gga Null Mice Demonstrates a Non-Redundant Role for Mammalian GGA2 during Development
Numerous studies using cultured mammalian cells have shown that the three GGAs (Golgi-localized, gamma-ear containing, ADP-ribosylation factor- binding proteins) function in the transport of cargo proteins between the trans- Golgi network and endosomes. However, the in vivo role(s) of these adaptor proteins and their possible functional redundancy has not been analyzed. In this study, the genes encoding GGAs1-3 were disrupted in mice by insertional mutagenesis. Loss of GGA1 or GGA3 alone was well tolerated whereas the absence of GGA2 resulted in embryonic or neonatal lethality, depending on the genetic background of the mice. Thus, GGA2 mediates a vital function that cannot be compensated for by GGA1and/or GGA3. The combined loss of GGA1 and GGA3 also resulted in a high incidence of neonatal mortality but in this case the expression level of GGA2 may be inadequate to compensate for the loss of the other two GGAs. We conclude that the three mammalian GGAs are essential proteins that are not fully redundant
International consensus recommendations on the diagnostic work-up for malformations of cortical development
Malformations of cortical development (MCDs) are neurodevelopmental disorders that result from abnormal development of the cerebral cortex in utero. MCDs place a substantial burden on affected individuals, their families and societies worldwide, as these individuals can experience lifelong drug-resistant epilepsy, cerebral palsy, feeding difficulties, intellectual disability and other neurological and behavioural anomalies. The diagnostic pathway for MCDs is complex owing to wide variations in presentation and aetiology, thereby hampering timely and adequate management. In this article, the international MCD network Neuro-MIG provides consensus recommendations to aid both expert and non-expert clinicians in the diagnostic work-up of MCDs with the aim of improving patient management worldwide. We reviewed the literature on clinical presentation, aetiology and diagnostic approaches for the main MCDΒ subtypes and collected data on current practices and recommendations from clinicians and diagnostic laboratories within Neuro-MIG. We reached consensus by 42 professionals from 20 countries, using expert discussions and a Delphi consensus process. We present a diagnostic workflow that can be applied to any individual with MCD and a comprehensive list of MCD-related genes with their associated phenotypes. The workflow is designed to maximize the diagnostic yield and increase the number of patients receiving personalized care and counselling on prognosis and recurrence risk
Polyfunctional T-Cell Responses Are Disrupted by the Ovarian Cancer Ascites Environment and Only Partially Restored by Clinically Relevant Cytokines
Host T-cell responses are associated with favorable outcomes in epithelial ovarian cancer (EOC), but it remains unclear how best to promote these responses in patients. Toward this goal, we evaluated a panel of clinically relevant cytokines for the ability to enhance multiple T-cell effector functions (polyfunctionality) in the native tumor environment.Experiments were performed with resident CD8+ and CD4+ T cells in bulk ascites cell preparations from high-grade serous EOC patients. T cells were stimulated with Ξ±-CD3 in the presence of 100% autologous ascites fluid with or without exogenous IL-2, IL-12, IL-18 or IL-21, alone or in combination. T-cell proliferation (Ki-67) and function (IFN-Ξ³, TNF-Ξ±, IL-2, CCL4, and CD107a expression) were assessed by multi-parameter flow cytometry. In parallel, 27 cytokines were measured in culture supernatants. While ascites fluid had variable effects on CD8+ and CD4+ T-cell proliferation, it inhibited T-cell function in most patient samples, with CD107a, IFN-Ξ³, and CCL4 showing the greatest inhibition. This was accompanied by reduced levels of IL-1Ξ², IL-1ra, IL-9, IL-17, G-CSF, GM-CSF, Mip-1Ξ±, PDGF-bb, and bFGF in culture supernatants. T-cell proliferation was enhanced by exogenous IL-2, but other T-cell functions were largely unaffected by single cytokines. The combination of IL-2 with cytokines engaging complementary signaling pathways, in particular IL-12 and IL-18, enhanced expression of IFN-Ξ³, TNF-Ξ±, and CCL4 in all patient samples by promoting polyfunctional T-cell responses. Despite this, other functional parameters generally remained inhibited.The EOC ascites environment disrupts multiple T-cell functions, and exogenous cytokines engaging diverse signaling pathways only partially reverse these effects. Our results may explain the limited efficacy of cytokine therapies for EOC to date. Full restoration of T-cell function will require activation of signaling pathways beyond those engaged by IL-2, IL-12, IL-18, and IL-21
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