151 research outputs found
CMB polarization as a probe of the anomalous nature of the Cold Spot
One of the most interesting explanations for the non-Gaussian Cold Spot (CS)
detected in the WMAP data by Vielva et al. 2004, is that it arises from the
interaction of the CMB radiation with a cosmic texture (Cruz et al. 2007b). In
this case, a lack of polarization is expected in the region of the spot, as
compared to the typical values associated to large fluctuations of a GIRF. In
addition, other physical processes related to a non-linear evolution of the
gravitational field could lead to a similar scenario. However, some of these
alternative scenarios (e.g., a large void in the large scale structure) have
been shown to be very unlikely. In this work we characterise the polarization
properties of the Cold Spot under both hypotheses: a large Gaussian spot and an
anomalous feature generated, for instance, by a cosmic texture. We propose a
methodology to distinguish between them, and we discuss its discrimination
power as a function of the instrumental noise level. In particular, we address
the cases of current experiments, like WMAP and Planck, and others in
development as QUIJOTE. We find that for an ideal experiment the Gaussian
hypothesis could be rejected at a significance level better than 0.8%. While
WMAP is far from providing useful information in this respect, we find that
Planck will be able to reach a significance of around 7%; in addition, we show
that the ground-based experiment QUIJOTE could provide a significance of around
1%. If these results are combined with the significance level found for the CS
in temperature, the capability of QUIJOTE and Planck to reject the alternative
hypothesis becomes 0.025% and 0.124%, respectively.Comment: 7 pages, 3 figures, accepted in MNRAS. Minor changes made to match
the final versio
Ипотека морского судна в контексте восстановление отечественного торгового флота в Украине
Торговельне мореплавство – одна з тих галузей світової економіки, яка має найбільш швидкий розвиток у наш час. Перш за все, це пов’язано із прискоренням міжнародного товарообміну. Наростання обсягів міжнародної торгівлі, у якій прагне приймати участь також Україна, обумовлює необхідність адекватно швидкого зростання її транспортної галузі. Попри значний транспортний потенціал, що має Україна, багато в чому завдячуючи її географічному положенню, стан вітчизняного транспортного комплексу й, особливо, його морської ланки, потребує покращення. Це, в свою чергу, безпосередньо залежить від правового регулювання, що впорядковує такі процеси
Incorporating chemical signalling factors into cell-based models of growing epithelial tissues
In this paper we present a comprehensive computational framework within which the effects of chemical signalling factors on growing epithelial tissues can be studied. The method incorporates a vertex-based cell model, in conjunction with a solver for the governing chemical equations. The vertex model provides a natural mesh for the finite element method (FEM), with node movements determined by force laws. The arbitrary Lagrangian–Eulerian formulation is adopted to account for domain movement between iterations. The effects of cell proliferation and junctional rearrangements on the mesh are also examined. By implementing refinements of the mesh we show that the finite element (FE) approximation converges towards an accurate numerical solution. The potential utility of the system is demonstrated in the context of Decapentaplegic (Dpp), a morphogen which plays a crucial role in development of the Drosophila imaginal wing disc. Despite the presence of a Dpp gradient, growth is uniform across the wing disc. We make the growth rate of cells dependent on Dpp concentration and show that the number of proliferation events increases in regions of high concentration. This allows hypotheses regarding mechanisms of growth control to be rigorously tested. The method we describe may be adapted to a range of potential application areas, and to other cell-based models with designated node movements, to accurately probe the role of morphogens in epithelial tissues
The Effect of a Physical Activity Program on the Total Number of Primary Care Visits in Inactive Patients: A 15-Month Randomized Controlled Trial
Abstract
Background: Effective promotion of exercise could result in substantial savings in healthcare cost expenses in terms of
direct medical costs, such as the number of medical appointments. However, this is hampered by our limited knowledge of
how to achieve sustained increases in physical activity.
Objectives: To assess the effectiveness of a Primary Health Care (PHC) based physical activity program in reducing the total
number of visits to the healthcare center among inactive patients, over a 15-month period.
Research Design: Randomized controlled trial.
Subjects: Three hundred and sixty-two (n = 362) inactive patients suffering from at least one chronic condition were
included. One hundred and eighty-three patients (n = 183; mean (SD); 68.3 (8.8) years; 118 women) were randomly allocated
to the physical activity program (IG). One hundred and seventy-nine patients (n = 179; 67.2 (9.1) years; 106 women) were
allocated to the control group (CG). The IG went through a three-month standardized physical activity program led by
physical activity specialists and linked to community resources.
Measures: The total number of medical appointments to the PHC, during twelve months before and after the program, was
registered. Self-reported health status (SF-12 version 2) was assessed at baseline (month 0), at the end of the intervention
(month 3), and at 12 months follow-up after the end of the intervention (month 15).
Results: The IG had a significantly reduced number of visits during the 12 months after the intervention: 14.8 (8.5). The CG
remained about the same: 18.2 (11.1) (P = .002).
Conclusions: Our findings indicate that a 3-month physical activity program linked to community resources is a shortduration,
effective and sustainable intervention in inactive patients to decrease rates of PHC visits.
Trial Registration: ClinicalTrials.gov NCT0071483
The Absence of Caspase-8 in the Dopaminergic System Leads to Mild Autism-like Behavior
In the last decade, new non-apoptotic roles have been ascribed to apoptotic caspases. This family of proteins plays an important role in the sculpting of the brain in the early stages of development by eliminating excessive and nonfunctional synapses and extra cells. Consequently, impairments in this process can underlie many neurological and mental illnesses. This view is particularly relevant to dopamine because it plays a pleiotropic role in motor control, motivation, and reward processing. In this study, we analyze the effects of the elimination of caspase-8 (CASP8) on the development of catecholaminergic neurons using neurochemical, ultrastructural, and behavioral tests. To do this, we selectively delete the CASP8 gene in cells that express tyrosine hydroxylase with the help of recombination through the Cre-loxP system. Our results show that the number of dopaminergic neurons increases in the substantia nigra. In the striatum, the basal extracellular level of dopamine and potassium-evoked dopamine release decreased significantly in mice lacking CASP8, clearly showing the low dopamine functioning in tissues innervated by this neurotransmitter. This view is supported by electron microscopy analysis of striatal synapses. Interestingly, behavioral analysis demonstrates that mice lacking CASP8 show changes reminiscent of autism spectrum disorders (ASD). Our research reactivates the possible role of dopamine transmission in the pathogenesis of ASD and provides a mild model of autism.Ministerio de Economía y Competitividad RTI2018-098645-B-I00, PID2019-109569GB-I00, RTI2018-099778-B-I00Junta de Andalucía P18-RT-1372, US-1264806, PI-0080-2017, PI-0009-2017, PI-0134-2018, PEMP-0008-2020, P20_00958, CTS-510Instituto de Salud Carlos III PI18/01691Instituto de Investigación e Innovación en Ciencias Biomédicas de Cádiz-INiBICA LI19/06IN-CO22, IN-C09European Union 95568
Mechanisms and mechanics of cell competition in epithelia
When fast-growing cells are confronted with slow-growing cells in a mosaic tissue, the slow-growing cells are often progressively eliminated by apoptosis through a process known as cell competition. The underlying signalling pathways remain unknown, but recent findings have shown that cell crowding within an epithelium leads to the eviction of cells from the epithelial sheet. This suggests that mechanical forces could contribute to cell elimination during cell competition
Planck 2013 results. XXII. Constraints on inflation
We analyse the implications of the Planck data for cosmic inflation. The Planck nominal mission temperature anisotropy measurements, combined with the WMAP large-angle polarization, constrain the scalar spectral index to be ns = 0:9603 _ 0:0073, ruling out exact scale invariance at over 5_: Planck establishes an upper bound on the tensor-to-scalar ratio of r < 0:11 (95% CL). The Planck data thus shrink the space of allowed standard inflationary models, preferring potentials with V00 < 0. Exponential potential models, the simplest hybrid inflationary models, and monomial potential models of degree n _ 2 do not provide a good fit to the data. Planck does not find statistically significant running of the scalar spectral index, obtaining dns=dln k = 0:0134 _ 0:0090. We verify these conclusions through a numerical analysis, which makes no slowroll approximation, and carry out a Bayesian parameter estimation and model-selection analysis for a number of inflationary models including monomial, natural, and hilltop potentials. For each model, we present the Planck constraints on the parameters of the potential and explore several possibilities for the post-inflationary entropy generation epoch, thus obtaining nontrivial data-driven constraints. We also present a direct reconstruction of the observable range of the inflaton potential. Unless a quartic term is allowed in the potential, we find results consistent with second-order slow-roll predictions. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit by __2 e_ _ 10; however, Bayesian evidence does not prefer these models. We constrain several single-field inflation models with generalized Lagrangians by combining power spectrum data with Planck bounds on fNL. Planck constrains with unprecedented accuracy the amplitude and possible correlation (with the adiabatic mode) of non-decaying isocurvature fluctuations. The fractional primordial contributions of cold dark matter (CDM) isocurvature modes of the types expected in the curvaton and axion scenarios have upper bounds of 0.25% and 3.9% (95% CL), respectively. In models with arbitrarily correlated CDM or neutrino isocurvature modes, an anticorrelated isocurvature component can improve the _2 e_ by approximately 4 as a result of slightly lowering the theoretical prediction for the ` <_ 40 multipoles relative to the higher multipoles. Nonetheless, the data are consistent with adiabatic initial conditions
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
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