Spectrum of low-lying s3QQˉs^{3}Q\bar{Q} configurations with negative parity

Spectrum of low-lying five-quark configurations with strangeness quantum number $S=-3$ and negative parity is studied in three kinds of constituent quark models, namely the one gluon exchange, Goldstone Boson exchange, and instanton-induced hyperfine interaction models, respectively. Our numerical results show that the lowest energy states in all the three employed models are lying at $\sim$1800 MeV, about 200 MeV lower than predictions of various quenched three-quark models. In addition, it is very interesting that the state with the lowest energy in one gluon exchange model is with spin 3/2, but 1/2 in the other two models.Comment: Version published in Phys. Rev.

Improving information filtering via network manipulation

Recommender system is a very promising way to address the problem of overabundant information for online users. Though the information filtering for the online commercial systems received much attention recently, almost all of the previous works are dedicated to design new algorithms and consider the user-item bipartite networks as given and constant information. However, many problems for recommender systems such as the cold-start problem (i.e. low recommendation accuracy for the small degree items) are actually due to the limitation of the underlying user-item bipartite networks. In this letter, we propose a strategy to enhance the performance of the already existing recommendation algorithms by directly manipulating the user-item bipartite networks, namely adding some virtual connections to the networks. Numerical analyses on two benchmark data sets, MovieLens and Netflix, show that our method can remarkably improve the recommendation performance. Specifically, it not only improve the recommendations accuracy (especially for the small degree items), but also help the recommender systems generate more diverse and novel recommendations.Comment: 6 pages, 5 figure

Imprints of the nuclear symmetry energy on gravitational waves from the axial w-modes of neutron stars

The eigen-frequencies of the axial w-modes of oscillating neutron stars are studied using the continued fraction method with an Equation of State (EOS) partially constrained by the recent terrestrial nuclear laboratory data. It is shown that the density dependence of the nuclear symmetry energy $E_{sym}(\rho)$ affects significantly both the frequencies and the damping times of these modes. Besides confirming the previously found universal behavior of the mass-scaled eigen-frequencies as functions of the compactness of neutron stars, we explored several alternative universal scaling functions. Moreover, the $w_{II}$-mode is found to exist only for neutron stars having a compactness of $M/R\geq 0.1078$ independent of the EOS used.Comment: Version appeared in Phys. Rev. C80, 025801 (2009

Investigation of possible virulence factors in Candida strains isolated from blood cultures

Background: The Candida species, which are one of the most common causes of nosocomial bloodstream infections, present with high mortality and morbidity rates. This study aims to investigate the production of esterase, phospholipase, proteinase, and biofilm formation ability of the Candida strains isolated from the blood cultures.Materials and Methods: Between June 2011 and July 2012, the Candida strains, which were isolated from blood cultures of a total of 50 patients, were studied. The esterase activity was analyzed in the Tween.80 agar, while phospholipase activity was studied in the egg yolk agar. The proteinase activity and biofilm formation were identified by using the petridish method and microplate method, respectively.Results: Of 50 specimens obtained from individual patients, 17 (34%) were identified as C. albicans, 14 (28%) as C. glabrata, 9 (18%) as C. parapsilosis, 5 (10%) as C. krusei, 4 (8%) as C. kefyr, and 1 (2%) as C. tropicalis. The rate of proteinase, phospholipase, and esterase positivity was higher in the C. albicans isolates. Biofilm formation was the highest in the C. parapsilosis strains.Conclusions: Higher rate of virulence factors in the most commonly isolated Candida species than other species indicates that these virulence factors play a crucial role in the pathogenesis.Key words: Biofilm, blood culture, candidemia, esterase, phospholipase, proteinas

Random attractors for degenerate stochastic partial differential equations

We prove the existence of random attractors for a large class of degenerate stochastic partial differential equations (SPDE) perturbed by joint additive Wiener noise and real, linear multiplicative Brownian noise, assuming only the standard assumptions of the variational approach to SPDE with compact embeddings in the associated Gelfand triple. This allows spatially much rougher noise than in known results. The approach is based on a construction of strictly stationary solutions to related strongly monotone SPDE. Applications include stochastic generalized porous media equations, stochastic generalized degenerate p-Laplace equations and stochastic reaction diffusion equations. For perturbed, degenerate p-Laplace equations we prove that the deterministic, infinite dimensional attractor collapses to a single random point if enough noise is added.Comment: 34 pages; The final publication is available at http://link.springer.com/article/10.1007%2Fs10884-013-9294-

Nuclear fragmentation: sampling the instabilities of binary systems

We derive stability conditions of Asymmetric Nuclear Matter ($ANM$) and discuss the relation to mechanical and chemical instabilities of general two-component systems. We show that the chemical instability may appear as an instability of the system against isoscalar-like rather than isovector-like fluctuations if the interaction between the two constituent species has an attractive character as in the case of $ANM$. This leads to a new kind of liquid-gas phase transition, of interest for fragmentation experiments with radioactive beams.Comment: 4 pages (LATEX), 3 Postscript figures, improved version, added reference

Somatic and cultural knowledge: drivers of a habitus-driven model of tacit knowledge acquisition

Purpose – The purpose of this paper is to identify and explain the role of individual learning and development in acquiring tacit knowledge in the context of the inexorable and intense continuous change (technological and otherwise) that characterizes our society today, and also to investigate the software (SW) sector, which is at the core of contemporary continuous change and is a paradigm of effective and intrinsic knowledge sharing (KS). This makes the SW sector unique and different from others where KS is so hard to implement. Design/methodology/approach – The study employed an inductive qualitative approach based on a multi-case study approach, composed of three successful SW companies in China. These companies are representative of the fabric of the sector, namely a small- and medium-sized enterprise, a large private company and a large state-owned enterprise. The fieldwork included 44 participants who were interviewed using a semi-structured script. The interview data were coded and interpreted following the Straussian grounded theory pattern of open coding, axial coding and selective coding. The process of interviewing was stopped when theoretical saturation was achieved after a careful process of theoretical sampling. Findings – The findings of this research suggest that individual learning and development are deemed to be the fundamental feature for professional success and survival in the continuously changing environment of the SW industry today. However, individual learning was described by the participants as much more than a mere individual process. It involves a collective and participatory effort within the organization and the sector as a whole, and a KS process that transcends organizational, cultural and national borders. Individuals in particular are mostly motivated by the pressing need to face and adapt to the dynamic and changeable environments of today’s digital society that is led by the sector. Software practitioners are continuously in need of learning, refreshing and accumulating tacit knowledge, partly because it is required by their companies, but also due to a sound awareness of continuous technical and technological changes that seem only to increase with the advances of information technology. This led to a clear theoretical understanding that the continuous change that faces the sector has led to individual acquisition of culture and somatic knowledge that in turn lay the foundation for not only the awareness of the need for continuous individual professional development but also for the creation of habitus related to KS and continuous learning. Originality/value – The study reported in this paper shows that there is a theoretical link between the existence of conducive organizational and sector-wide somatic and cultural knowledge, and the success of KS practices that lead to individual learning and development. Therefore, the theory proposed suggests that somatic and cultural knowledge are crucial drivers for the creation of habitus of individual tacit knowledge acquisition. The paper further proposes a habitus-driven individual development (HDID) Theoretical Model that can be of use to both academics and practitioners interested in fostering and developing processes of KS and individual development in knowledge-intensive organization

Strong Electron-Phonon Coupling in Superconducting MgB2_2: A Specific Heat Study

We report on measurements of the specific heat of the recently discovered superconductor MgB$_2$ in the temperature range between 3 and 220 K. Based on a modified Debye-Einstein model, we have achieved a rather accurate account of the lattice contribution to the specific heat, which allows us to separate the electronic contribution from the total measured specific heat. From our result for the electronic specific heat, we estimate the electron-phonon coupling constant $\lambda$ to be of the order of 2, significantly enhanced compared to common weak-coupling values $\leq 0.4$. Our data also indicate that the electronic specific heat in the superconducting state of MgB$_2$ can be accounted for by a conventional, s-wave type BCS-model.Comment: 4 pages, 4 figure

Neutron and proton drip lines using the modified Bethe-Weizsacker mass formula

Proton and neutron separation energies have been calculated using the extended Bethe-Weizsacker mass formula. This modified Bethe-Weizsacker mass formula describes minutely the positions of all the old and the new magic numbers. It accounts for the disappearance of some traditional magic numbers for neutrons and provides extra stability for some new neutron numbers. The neutron and proton drip lines have been predicted using this extended Bethe-Weizsacker mass formula. The implications of the proton drip line on the astrophysical rp-process and of the neutron drip line on the astrophysical r-process have been discussed.Comment: 5 pages, 2 figure