525 research outputs found
Black Hole Genesis of Dark Matter
We present a purely gravitational infra-red-calculable production mechanism
for dark matter (DM). The source of both the DM relic abundance and the hot
Standard Model (SM) plasma is a primordial density of micro black holes (BHs),
which evaporate via Hawking emission into both the dark and SM sectors. The
mechanism has four qualitatively different regimes depending upon whether the
BH evaporation is `fast' or `slow' relative to the initial Hubble rate, and
whether the mass of the DM particle is `light' or `heavy' compared to the
initial BH temperature. For each of these regimes we calculate the DM yield,
, as a function of the initial state and DM mass and spin. In the `slow'
regime depends on only the initial BH mass over a wide range of initial
conditions, including scenarios where the BHs are a small fraction of the
initial energy density. The DM is produced with a highly non-thermal energy
spectrum, leading in the `light' DM mass regime ( and
above depending on DM spin) to a strong constraint from free-streaming, but
also possible observational signatures in structure formation in the spin 3/2
and 2 cases. The `heavy' regime ( to
depending on spin) is free of these constraints and provides
new possibilities for DM detection. In all cases there is a dark radiation
component predicted.Comment: 16 pages, 8 figures. Fixed typos and added reference
Bouncing localized structures in a liquid-crystal light-valve experiment
Experimental evidence of bouncing localized structures in a nonlinear optical
system is reported.Comment: 4 page
Using Topological Data Analysis for diagnosis pulmonary embolism
Pulmonary Embolism (PE) is a common and potentially lethal condition. Most
patients die within the first few hours from the event. Despite diagnostic
advances, delays and underdiagnosis in PE are common.To increase the diagnostic
performance in PE, current diagnostic work-up of patients with suspected acute
pulmonary embolism usually starts with the assessment of clinical pretest
probability using plasma d-Dimer measurement and clinical prediction rules. The
most validated and widely used clinical decision rules are the Wells and Geneva
Revised scores. We aimed to develop a new clinical prediction rule (CPR) for PE
based on topological data analysis and artificial neural network. Filter or
wrapper methods for features reduction cannot be applied to our dataset: the
application of these algorithms can only be performed on datasets without
missing data. Instead, we applied Topological data analysis (TDA) to overcome
the hurdle of processing datasets with null values missing data. A topological
network was developed using the Iris software (Ayasdi, Inc., Palo Alto). The PE
patient topology identified two ares in the pathological group and hence two
distinct clusters of PE patient populations. Additionally, the topological
netowrk detected several sub-groups among healthy patients that likely are
affected with non-PE diseases. TDA was further utilized to identify key
features which are best associated as diagnostic factors for PE and used this
information to define the input space for a back-propagation artificial neural
network (BP-ANN). It is shown that the area under curve (AUC) of BP-ANN is
greater than the AUCs of the scores (Wells and revised Geneva) used among
physicians. The results demonstrate topological data analysis and the BP-ANN,
when used in combination, can produce better predictive models than Wells or
revised Geneva scores system for the analyzed cohortComment: 18 pages, 5 figures, 6 tables. arXiv admin note: text overlap with
arXiv:cs/0308031 by other authors without attributio
Serendipia en la música de Claude Debussy a San Lazaro
Based on an empirical work, this article provides a critical
examination of whether and to what extent the phenomenon of
serendipity can be found in music and in the process of
composition. Aiming to suggest a probable methodological approach to answer this question, I'll be examining the interaction between music and diverse sociocultural circumstances, looking at the music history of the last 500 years. This methodological approach will be applied to examine the existence of serendipity in the compositions,
compositional concepts and in the world perceptions of Claude Debussy, John Cage, Juan MarÃa Solare and the band San Lazaro
Role of Epigenetic Modification and Immunomodulation in a Murine Prostate Cancer Model
INTRODUCTION. Decreased expression of highly immunogenic cancer-testis antigens (CTA) might help tumor to achieve low immunogenicity, escape immune surveillance and grow unimpeded. Our aim was to evaluate CTA expression in tumor and normal tissues and to investigate possible means of improving the immune response in a murine prostate cancer (CaP) model by using the combination of epigenetic modifier 5-azacitidine (5-AzaC) and immunomodulator lenalidomide. No study to date has examined the effect of this combination on the prostate cancer or its impact on antigen-presenting cells (APC). MATERIALS AND METHODS. Gene microarrays were performed to compare expression of several CTA in murine prostate cancer (RM-1 cells) and normal prostate. RM-1 cells were treated with 5-AzaC and real-time PCR was performed to investigate the expression of several CTA. Western blotting was used to determine whether expression of CTA-specific mRNA induced by 5-AzaC resulted in increase in the corresponding protein. Effect of the epigenetic agents and immunomodulators was assessed on dendritic cells (DC) using flow cytometry, ELISA and T-cell proliferation assay. RESULTS. Gene arrays demonstrated decreased expression of 35 CTA in CaP tissue compared to normal prostate. 5-AzaC treatment of RM-1 prostate cancer cells upregulated the expression of all 13 CTA tested in a dose-dependent fashion. DC were treated with 5-AzaC and lenalidomide and the expression of surface markers MHC Class I, MHC Class II, CD80, CD86, CD 205, and CD40 was increased. Combination of 5-AzaC and lenalidomide enhances the ability of DC to stimulate T-cell proliferation in mixed leukocyte reaction. Secretion of IL-12 and IL-15 by DC increased significantly with addition of 5-AzaC or 5-AzaC and lenalidomide. CONCLUSIONS. Decreased expression of CTA by prostate cancer may be a means of escaping immune monitoring. Combination of epigenetic modifications and immunomodulation by 5-AzaC and lenalidomide increased tumor immunogenicity and enhanced DC function and may be used in the treatment of advanced prostate cancer
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