128 research outputs found
Anisotropic Radial Layout for Visualizing Centrality and Structure in Graphs
This paper presents a novel method for layout of undirected graphs, where
nodes (vertices) are constrained to lie on a set of nested, simple, closed
curves. Such a layout is useful to simultaneously display the structural
centrality and vertex distance information for graphs in many domains,
including social networks. Closed curves are a more general constraint than the
previously proposed circles, and afford our method more flexibility to preserve
vertex relationships compared to existing radial layout methods. The proposed
approach modifies the multidimensional scaling (MDS) stress to include the
estimation of a vertex depth or centrality field as well as a term that
penalizes discord between structural centrality of vertices and their alignment
with this carefully estimated field. We also propose a visualization strategy
for the proposed layout and demonstrate its effectiveness using three social
network datasets.Comment: Appears in the Proceedings of the 25th International Symposium on
Graph Drawing and Network Visualization (GD 2017
Mixing and diffusion in a two-type population
The outbreak of epidemics, the rise of religious radicalization
or the motivational influence of fellow students in classrooms
are some of the issues that can be described as diffusion
processes in heterogeneous groups. Understanding the role
that interaction patterns between groups (e.g. homophily or
segregation) play in the diffusion of certain traits or behaviours
is a major challenge for contemporary societies. Here, we study
the impact on diffusion processes of mixing (or, alternatively,
segregating) two groups that present different sensitivities or
propensities to contagion. We find non-monotonic effects of
mixing and inefficient segregation levels, i.e. situations where
a change in the mixing level can benefit both groups, e.g.
where an increase in the mixing level can reduce the expected
contagion levels in both groups. These findings can have
fundamental consequences for the design of inclusion policies.D.L.-P. from the Spanish Ministry of Science and
Innovation (ECO2011-22919) and from project ECO2017-83147-C2-1-P (MINECO/AEI/FEDER, UE). L.R.I. and S.S.I.
from project ECO2017-83147-C2-2-P (MINECO/AEI/FEDER, UE
Fashion, Cooperation, and Social Interactions
Fashion plays such a crucial rule in the evolution of culture and society
that it is regarded as a second nature to the human being. Also, its impact on
economy is quite nontrivial. On what is fashionable, interestingly, there are
two viewpoints that are both extremely widespread but almost opposite:
conformists think that what is popular is fashionable, while rebels believe
that being different is the essence. Fashion color is fashionable in the first
sense, and Lady Gaga in the second. We investigate a model where the population
consists of the afore-mentioned two groups of people that are located on social
networks (a spatial cellular automata network and small-world networks). This
model captures two fundamental kinds of social interactions (coordination and
anti-coordination) simultaneously, and also has its own interest to game
theory: it is a hybrid model of pure competition and pure cooperation. This is
true because when a conformist meets a rebel, they play the zero sum matching
pennies game, which is pure competition. When two conformists (rebels) meet,
they play the (anti-) coordination game, which is pure cooperation. Simulation
shows that simple social interactions greatly promote cooperation: in most
cases people can reach an extraordinarily high level of cooperation, through a
selfish, myopic, naive, and local interacting dynamic (the best response
dynamic). We find that degree of synchronization also plays a critical role,
but mostly on the negative side. Four indices, namely cooperation degree,
average satisfaction degree, equilibrium ratio and complete ratio, are defined
and applied to measure people's cooperation levels from various angles. Phase
transition, as well as emergence of many interesting geographic patterns in the
cellular automata network, is also observed.Comment: 21 pages, 12 figure
Transient evolution of C-type shocks in dusty regions of varying density
Outflows of young stars drive shocks into dusty, molecular regions. Most
models of such shocks assume that they are steady and propagating perpendicular
to the magnetic field. Real shocks often violate both of these assumptions and
the media through which they propagate are inhomogeneous. We use the code
employed previously to produce the first time-dependent simulations of
fast-mode, oblique C-type shocks interacting with density perturbations. We
include a self-consistent calculation of the thermal and ionisation balances
and a fluid treatment of grains. We identify features that develop when a
multifluid shock encounters a density inhomogeneity to investigate whether any
part of the precursor region ever behaves in a quasi-steady fashion. If it does
the shock may be modelled approximately without solving the time-dependent
hydromagnetic equations. Simulations were made for initially steady oblique
C-type shocks encountering density inhomogeneities. For a semi-finite
inhomogeneity with a density larger than the surrounding medium, a transmitted
shock evolves from being J-type to a steady C-type shock on a timescale
comparable to the ion-flow time through it. A sufficiently upstream part of the
precursor of an evolving J-type shock is quasi-steady. The ion-flow timescale
is also relevant for the evolution of a shock moving into a region of
decreasing density. The models for shocks propagating into regions in which the
density increases and then decreases to its initial value cannot be entirely
described in terms of the results obtained for monotonically increasing and
decreasing densities. For the latter model, the long-term evolution to a C-type
shock cannot be approximated by quasi-steady models.Comment: 11 pages, 9 figure
Antimicrobial and antioxidant effects of combined high pressure processingand sage in beef burgers during prolonged chilled storage
The combined effect of sage (0.3 and 0.6%) and high pressure processing (HPP) [300 MPa (10 min, 9.9 °C) and 600 MPa (10 min, 10.2 °C)] on the antimicrobial and antioxidant characteristics of beef burgers during prolonged chilled storage (60 days) was analysed. Sage powder showed antioxidant and antimicrobial activities, but the addition of sage powder to burgers had no apparent effect on antimicrobial activity; however, antioxidant activity was detected as measured by TBARS, hexanal and photochemiluminescence (PCL). In general, lipid oxidation increased in all samples during storage. HPP at 600 MPa had no effect on lipid oxidation but caused mesophilic and psychrotrophic counts to remain close to the detection limit for at least 6 days. Significant correlations were found between lipid oxidation measured by TBARS and PCL and between TBARS with hexanal over the storage period. Sage had no detrimental effects on sensory attributes of burgers.
Industrial relevance
Sage is an aromatic plant with excellent antimicrobial and antioxidant properties. High pressure processing (HPP) is an efficient non-thermal preservation technology. As far as the authors are aware, very few studies have holistically addressed the question of stability (microbial spoilage and oxidation of lipids) of traditionally-prepared burgers as affected by HPP and addition of a natural plant. This paper examines the possible application of both treatments so as to obtain beef burgers with suitable oxidative and microbiological stability over prolonged chilled storage without this affecting sensory attributes.info:eu-repo/semantics/acceptedVersio
A rotating molecular disk toward IRAS 18162-2048, the exciting source of HH 80-81
We present several molecular line emission arcsec and subarcsec observations
obtained with the Submillimeter Array (SMA) in the direction of the massive
protostar IRAS 18162-2048, the exciting source of HH 80-81.
The data clearly indicates the presence of a compact (radius~425-850 AU) SO2
structure, enveloping the more compact (radius~150 AU) 1.4 millimeter dust
emission (reported in a previous paper). The emission spatially coincides with
the position of the prominent thermal radio jet which terminates at the HH
80-81 and HH 80N Herbig-Haro objects. Furthermore, the molecular emission is
elongated in the direction perpendicular to the axis of the thermal radio jet,
suggesting a disk-like structure. We derive a total dynamic mass (disk-like
structure and protostar) of 11-15 msun. The SO2 spectral line data also allow
us to constrain the structure temperature between 120-160 K and the volume
density > 2x10^9 cm-3. We also find that such a rotating flattened system could
be unstable due to gravitational disturbances.
The data from C17O line emission show a dense core within this star-forming
region. Additionally, the H2CO and the SO emissions appear clumpy and trace the
disk-like structure, a possible interaction between a molecular core and the
outflows, and in part, the cavity walls excavated by the thermal radio jet.Comment: 13 pages,11 figures. Accepted in the AJ, 07-15-201
Conditional expression of HGAL leads to the development of diffuse large B-cell lymphoma in mice
Diffuse large B-cell lymphomas (DLBCLs) are clinically and genetically heterogeneous tumors. Deregulation of diverse biological processes specific to B cells, such as B-cell receptor (BCR) signaling and motility regulation, contribute to lymphomagenesis. Human germinal center associated lymphoma (HGAL) is a B-cell–specific adaptor protein controlling BCR signaling and B lymphocyte motility. In normal B cells, it is expressed in germinal center (GC) B lymphocytes and promptly downregulated upon further differentiation. The majority of DLBCL tumors, primarily GC B-cell types, but also activated types, express HGAL. To investigate the consequences of constitutive expression of HGAL in vivo, we generated mice that conditionally express human HGAL at different stages of hematopoietic development using 3 restricted Cre-mediated approaches to initiate expression of HGAL in hematopoietic stem cells, pro-B cells, or GC B cells. Following immune stimulation, we observed larger GCs in mice in which HGAL expression was initiated in GC B cells. All 3 mouse strains developed DLBCL at a frequency of 12% to 30% starting at age 13 months, leading to shorter survival. Immunohistochemical studies showed that all analyzed tumors were of the GC B-cell type. Exon sequencing revealed mutations reported in human DLBCL. Our data demonstrate that constitutive enforced expression of HGAL leads to DLBCL development
Predictors of Visceral Leishmaniasis Relapse in HIV-Infected Patients: A Systematic Review
Visceral leishmaniasis (VL) is the most serious form of an insect-transmitted parasitic disease prevalent in 70 countries. The disease is caused by species of the L. donovani complex found in different geographical regions. These parasites have substantially different clinical, drug susceptibility and epidemiological characteristics. According to data from the World Health Organization, the areas where HIV-Leishmania co-infection is distributed are extensive. HIV infection increases the risk of developing VL, reduces the likelihood of a therapeutic response, and greatly increases the probability of relapse. A better understanding of the factors promoting relapses is essential; therefore we performed a systematic review of articles involving all articles assessing the predictors of VL relapse in HIV-infected individuals older than 14 years of age. Out of 178 relevant articles, 18 met the inclusion criteria and in total, data from 1017 patients were analyzed. We identified previous episodes of VL relapse, CD4+ lymphocyte count fewer than 100 cells/mL at VL diagnosis, and the absence of an increase in CD4+ counts at follow-up as major factors associated with VL relapse. Knowledge of relapse predictors can help to identify patients with different degrees of risk, facilitate and direct prophylaxis choices, and aid in patient counseling
Lmo2 expression defines tumor cell identity during T-cell leukemogenesis
The impact of LMO2 expression on cell lineage decisions during T-cell leukemogenesis remains largely elusive. Using genetic lineage tracing, we have explored the potential of LMO2 in dictating a T-cell malignant phenotype. We first initiated LMO2 expression in hematopoietic stem/progenitor cells and maintained its expression in all hematopoietic cells. These mice develop exclusively aggressive human-like T-ALL. In order to uncover a potential exclusive reprogramming effect of LMO2 in murine hematopoietic stem/progenitor cells, we next showed that transient LMO2 expression is sufficient for oncogenic function and induction of T-ALL. The resulting T-ALLs lacked LMO2 and its target-gene expression, and histologically, transcriptionally, and genetically similar to human LMO2-driven T-ALL. We next found that during T-ALL development, secondary genomic alterations take place within the thymus. However, the permissiveness for development of T-ALL seems to be associated with wider windows of differentiation than previously appreciated. Restricted Cre-mediated activation of Lmo2 at different stages of B-cell development induces systematically and unexpectedly T-ALL that closely resembled those of their natural counterparts. Together, these results provide a novel paradigm for the generation of tumor T cells through reprogramming in vivo and could be relevant to improve the response of T-ALL to current therapies.J.H. has been supported by the German Cancer Aid (Project 110997 and Translational Oncology Program 70112951), the German Jose Carreras Leukemia Foundation (DJCLS 02R/2016), Deutsches Konsortium für Translationale Krebsforschung (DKTK), Joint funding (Targeting MYC L*10), the Kinderkrebsstiftung (2016/17), and the “Elterninitiative Kinderkrebsklinik e.V. Düsseldorf”. SG has been supported by a scholarship of the Hochschule Bonn-Rhein-Sieg. AB has been supported by the German Children's Cancer Foundation and the Federal Ministry of Education and Research, Bonn, Germany. Research in ISG group is partially supported by FEDER and by MINECO (SAF2012-32810, SAF2015-64420-R, and Red de Excelencia Consolider OncoBIO SAF2014-57791-REDC), Instituto de Salud Carlos III (PIE14/00066), ISCIII- Plan de Ayudas IBSAL 2015 Proyectos Integrados (IBY15/00003), by Junta de Castilla y León (BIO/SA51/15, CSI001U14, UIC-017, and CSI001U16), Fundacion Inocente Inocente, and by the ARIMMORA project (European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 282891). ISG Lab is a member of the EuroSyStem and the DECIDE Network funded by the European Union under the FP7 program. AB and ISG have been supported by the German Carreras Foundation (DJCLS R13/26). IGR was supported by BES-Ministerio de Economía y Competitividad (BES-2013-063789). AML and GRH were supported by FSE-Conserjería de Educación de la Junta de Castilla y León (CSI001-13, CSI001-15). Research in CVD group is partially supported by FEDER, “Miguel Servet” Grant (CP14/00082—AES 2013-2016) from the Instituto de Salud Carlos III (Ministerio de Economía y Competitividad), “Fondo de Investigaciones Sanitarias/Instituto de Salud Carlos III” (PI17/00167), and by the Lady Tata International Award for Research in Leukaemia 2016–2017
Stochastic Approximation to Understand Simple Simulation Models
This paper illustrates how a deterministic approximation of a stochastic process
can be usefully applied to analyse the dynamics of many simple simulation models. To
demonstrate the type of results that can be obtained using this approximation, we present two
illustrative examples which are meant to serve as methodological references for researchers
exploring this area. Finally, we prove some convergence results for simulations of a family
of evolutionary games, namely, intra-population imitation models in n-player games with
arbitrary payoffs.Ministerio de Educación (JC2009- 00263), Ministerio de Ciencia e Innovación (CONSOLIDER-INGENIO 2010: CSD2010-00034, DPI2010-16920
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