682 research outputs found

    Semileptonic Decays of Heavy Omega Baryons in a Quark Model

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    The semileptonic decays of Ωc\Omega_c and Ωb\Omega_b are treated in the framework of a constituent quark model developed in a previous paper on the semileptonic decays of heavy Λ\Lambda baryons. Analytic results for the form factors for the decays to ground states and a number of excited states are evaluated. For Ωb\Omega_b to Ωc\Omega_c the form factors obtained are shown to satisfy the relations predicted at leading order in the heavy-quark effective theory at the non-recoil point. A modified fit of nonrelativistic and semirelativistic Hamiltonians generates configuration-mixed baryon wave functions from the known masses and the measured \lcle rate, with wave functions expanded in both harmonic oscillator and Sturmian bases. Decay rates of \ob to pairs of ground and excited \omc states related by heavy-quark symmetry calculated using these configuration-mixed wave functions are in the ratios expected from heavy-quark effective theory, to a good approximation. Our predictions for the semileptonic elastic branching fraction of ΩQ\Omega_Q vary minimally within the models we use. We obtain an average value of (84±\pm 2%) for the fraction of Ωc→Ξ(∗)\Omega_c\to \Xi^{(*)} decays to ground states, and 91% for the fraction of Ωc→Ω(∗)\Omega_c\to \Omega^{(*)} decays to the ground state Ω\Omega. The elastic fraction of \ob \to \omc ranges from about 50% calculated with the two harmonic-oscillator models, to about 67% calculated with the two Sturmian models.Comment: 52 pages, 8 figure

    The no-core shell model with general radial bases

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    Calculations in the ab initio no-core shell model (NCSM) have conventionally been carried out using the harmonic-oscillator many-body basis. However, the rapid falloff (Gaussian asymptotics) of the oscillator functions at large radius makes them poorly suited for the description of the asymptotic properties of the nuclear wavefunction. We establish the foundations for carrying out no-core configuration interaction (NCCI) calculations using a basis built from general radial functions and discuss some of the considerations which enter into using such a basis. In particular, we consider the Coulomb-Sturmian basis, which provides a complete set of functions with a realistic (exponential) radial falloff.Comment: 7 pages, 3 figures; presented at Horizons on Innovative Theories, Experiments, and Supercomputing in Nuclear Physics 2012, New Orleans, Louisiana, June 4-7, 2012; submitted to J. Phys. Conf. Se

    Dental fear: a narrative review

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    The dental fear and anxiety (DFA) is a common phenomenon around the world. From children to the adults, most of the people become frightened when they face any dental discomfort and they need to visit a dentist and go through a treatment procedure in a dental set up. This narrative review tends to identify the causes behind DFA, its consequences and management of DFA from different studies which were conducted previously. This study is a narrative review of DFA. This study is mainly based on the secondary data from different articles and journals which were available online. After the proper screening from 154 titles, the final review included 68 articles. Based on different studies, it is found that DFA in quiet common in the people of all ages. The studies had found that dental fear and anxiety most often results from a traumatic past dental experience. Friendly dental office environment is an effective way in reducing dental fear and anxiety. Psychotherapeutic management is also important is managing DFA like behavior-management techniques, relaxation techniques, distraction, guided imagery, hypnotherapy, acupuncture, systematic desensitization or exposure therapy, positive reinforcement, cognitive restructuring and pharmacological management. The techniques for managing DFA can be the effective solution for reducing stress and make the treatment process more comfortable.

    Heavy Baryons in a Quark Model

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    A quark model is applied to the spectrum of baryons containing heavy quarks. The model gives masses for the known heavy baryons that are in agreement with experiment, but for the doubly-charmed baryon Cascade_{cc}, the model prediction is too heavy. Mixing between the Cascade_Q and Cascade_Q^\prime states is examined and is found to be small for the lowest lying states. In contrast with this, mixing between the Cascade_{bc} and Cascade_{bc}^\prime states is found to be large, and the implication of this mixing for properties of these states is briefly discussed. We also examine heavy-quark spin-symmetry multiplets, and find that many states in the model can be placed in such multiplets. We compare our predictions with those of a number of other authors.Comment: Version published in International Journal of Modern Physics

    Improved hematopoiesis in anemic Sl/Sld mice by splenectomy and therapeutic transplantation of a hematopoietic microenvironment

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    The ability of a clonal hematopoiesis-supportive bone-marrow stromal cell line GBlneor to engraft and alter the microenvironment-induced anemia of Sl/Sld mice was studied. Prior to stromal cell transplantation, Sl/Sld mice received 1 Gy total body irradiation (TBI) and 13 Gy to the right hind limb. Two months after intravenous (IV) injection of 5 x 10(5) GBlneor cells, 54.4% +/- 17.0% donor origin (G418r) colony-forming cells were recovered from the right hind limb of Sl/Sld mice. Long-term bone marrow cultures (LTBMCs) established from GBlneor-transplanted mice produced 189.5 CFU-GEMM-forming progenitors/flask over 10 weeks compared with 52.7 +/- 6.2 CFU-GEMM forming progenitors/flask from irradiated nontransplanted Sl/Sld mice. A partial correction of macrocytic anemia was detected 2 months after GBlneor transplantation in splenectomized, irradiated Sl/Sld mice (HgB 7.2 +/- 0.4 g/dL; MCV 68.3 +/- 7.0 fL) compared to splenectomized, irradiated, nontransplanted Sl/Sld mice (HgB 5.5 +/- 1.1 g/dL; MCV 76 +/- 8.5 fL) or control Sl/Sld mice (HgB 5.4 +/- 0.5 g/dL; MCV 82.4 +/- 1.3 fL). Mean RBC volume distribution analysis showed a 2.5-fold increase in percentage of peripheral blood RBCs with MCV less than or equal to 45 fL and confirmed reduction of the MCV in splenectomized-GBlneor-transplanted mice compared to control Sl/Sld mice. A hematopoiesis-suppressive clonal stromal cell line derived from LTBMCs of Sl/Sld mice (Sldneor) engrafted as effectively (43.5% +/- 1.2% G418r CFU-F/limb) as did GBlneor cells (38.3% +/- 0.16% G418r CFU-F/limb) to the irradiated right hind limbs of C57Bl/6 mice. LTBMCs established after 2 or 6 months from Sldneor-transplanted mice showed decreased hematopoiesis (182 +/- 12 [2 months] and 3494.3 +/- 408.1 [6 months] CFU-GEMM forming progenitors/flask over 10 weeks) compared to those established from GBlneor-transplanted mice (5980 +/- 530 [2 months] and 7728 +/- 607, [6 months] CFU-GEMM progenitors forming/flask). Thus, transplantation of clonal bone-marrow stromal cell lines in vivo can stably transfer their physiologic properties to normal or mutant mice

    LCrowdV: Generating Labeled Videos for Simulation-based Crowd Behavior Learning

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    We present a novel procedural framework to generate an arbitrary number of labeled crowd videos (LCrowdV). The resulting crowd video datasets are used to design accurate algorithms or training models for crowded scene understanding. Our overall approach is composed of two components: a procedural simulation framework for generating crowd movements and behaviors, and a procedural rendering framework to generate different videos or images. Each video or image is automatically labeled based on the environment, number of pedestrians, density, behavior, flow, lighting conditions, viewpoint, noise, etc. Furthermore, we can increase the realism by combining synthetically-generated behaviors with real-world background videos. We demonstrate the benefits of LCrowdV over prior lableled crowd datasets by improving the accuracy of pedestrian detection and crowd behavior classification algorithms. LCrowdV would be released on the WWW

    Recent models for adaptive personality differences: a review

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    In this paper we review recent models that provide adaptive explanations for animal personalities: individual differences in behaviour (or suites of correlated behaviours) that are consistent over time or contexts. We start by briefly discussing patterns of variation in behaviour that have been documented in natural populations. In the main part of the paper we discuss models for personality differences that (i) explain animal personalities as adaptive behavioural responses to differences in state, (ii) investigate how feedbacks between state and behaviour can stabilize initial differences among individuals and (iii) provide adaptive explanations for animal personalities that are not based on state differences. Throughout, we focus on two basic questions. First, what is the basic conceptual idea underlying the model? Second, what are the key assumptions and predictions of the model? We conclude by discussing empirical features of personalities that have not yet been addressed by formal modelling. While this paper is primarily intended to guide empiricists through current adaptive theory, thereby stimulating empirical tests of these models, we hope it also inspires theoreticians to address aspects of personalities that have received little attention up to now

    Today’s children tomorrow’s changemakers: educational resources to develop entrepreneurial skills

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    [EN] Entrepreneurship is one of the main objectives of the European Union to ensure that people have the right skills for jobs. It is also part of the Key Competences for Lifelong Learning. Different stakeholders should be involved in fostering entrepreneurial skills. These skills need to be developed from an early stage. For this reason, teachers and parents have an essential responsibility in helping students gain entrepreneurial skills. This work describes the project Today’s Children Tomorrow’s Changemakers; a European funded project focused on developing entrepreneurial skills at primary school through a set of educational resources for teachers and children

    Attitudes towards code-switching among adult mono- and multilingual language users

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    The present study investigates inter-individual variation (linked to personality traits, multilingualism and sociobiographical variables) in attitudes towards code-switching (CS) among 2070 multilinguals. Data were collected through an on-line questionnaire. We found that high levels of Tolerance of Ambiguity and Cognitive Empathy, and low levels of Neuroticism are linked with significantly more positive attitudes towards CS. Knowing many languages had a marginally positive effect. A more fine-grained analysis revealed that participants with mid-range global proficiency values were less positive towards CS than those at the lower and higher end of the scale. Participants who grew up in a bilingual family and in an ethnically diverse environment, and currently worked in an ethnically diverse environment had significantly more positive attitudes towards CS. Female participants and those with the lowest and highest levels of education appreciated CS most, and participants in their teens and twenties appreciated CS less than older participants. The findings thus show that the attitudes towards CS are linked to personality, language learning history and current linguistic practices, as well as some sociobiographical variables

    Dual Space of a Lattice as the Completion of a Pervin Space

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    16th International Conference, RAMiCS 2017, Lyon, France, May 15-18, 2017, ProceedingsInternational audienceThis survey paper presents well-known results from a new angle. A Pervin space is a set X equipped with a set of subsets,called the blocks of the Pervin space. Blocks are closed under finite intersections and finite unions and hence form a lattice of subsets of X. Pervin spaces are thus easier to define than topological spaces or (quasi)-uniform spaces. As a consequence, most of the standard topological notions, like convergence and cluster points, specialisation order, filtersand Cauchy filters, complete spaces and completion are much easier to define for Pervin spaces. In particular, the completion of a Pervin space turns out to be the dual space (in the sense of Stone) of the original lattice.We show that any lattice of subsets can be described by a set of inequations of the form u ≀ v, where u and v are elements of its dual space. Applications to formal languages and complexity classes are given.Cet article de synthĂšse prĂ©sente des rĂ©sultats bien connus sous un nouvel angle. Un espace de Pervin est unensemble X Ă©quipĂ© d'un ensemble de parties, appelĂ© les blocs de l'espace de Pervin. Les blocs sont fermĂ©s par intersection finie et union finie et forment ainsi un treillis de parties de X. Les espaces de Pervin sont doncplus faciles Ă  dĂ©finir que les espaces topologiques ou les espaces (quasi-)uniformes. Par consĂ©quent, la plupart des notions topologiques, comme la convergence et les points d'adhĂ©rence, l'ordre de spĂ©cialisation, les filtres de Cauchy, les espaces complets et la complĂ©tion sont beaucoup plus faciles Ă  dĂ©finir pour les espaces Pervin. En particulier, la complĂ©tion d'un espace Pervin s'avĂšre ĂȘtre l'espace dual (au sens de Stone) du treillis de dĂ©part.Nous montrons que tout treillis de parties peut ĂȘtre dĂ©crit par un ensemble d'inĂ©quations de la forme u ≀ v, oĂč u et v sont des Ă©lĂ©ments de son espace dual. On donne des applications aux langages formels et aux classes de complexitĂ©
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