Constraints on hidden gravitons from fifth-force experiments and stellar energy loss

We study different phenomenological signatures associated with new spin-2 particles. These new degrees of freedom, that we call hidden gravitons, arise in different high-energy theories such as extra-dimensional models or extensions of General Relativity. At low energies, hidden gravitons can be generally described by the Fierz-Pauli Lagrangian. Their phenomenology is parameterized by two dimensionful constants: their mass and their coupling strength. In this work, we analyze two different sets of constraints. On the one hand, we study potential deviations from the inverse-square law on solar-system and laboratory scales. To extend the constraints to scales where the laboratory probes are not competitive, we also study consequences on astrophysical objects. We analyze in detail the processes that may take place in stellar interiors and lead to emission of hidden gravitons, acting like an additional source of energy loss.Comment: 15 pages, 7 figure

Non-comoving Cosmology

One of the fundamental assumptions of the standard $\Lambda$CDM cosmology is that, on large scales, all the matter-energy components of the Universe share a common rest frame. This seems natural for the visible sector, that has been in thermal contact and tightly coupled in the primeval Universe. The dark sector, on the other hand, does not have any non-gravitational interaction known to date and therefore, there is no a priori reason to impose that it is comoving with ordinary matter. In this work we explore the consequences of relaxing this assumption and study the cosmology of non-comoving fluids. We show that it is possible to construct a homogeneous and isotropic cosmology with a collection of fluids moving with non-relativistic velocities. Our model extends $\Lambda$CDM with the addition of a single free parameter $\beta_0$, the initial velocity of the visible sector with respect to the frame that observes a homogeneous and isotropic universe. This modification gives rise to a rich phenomenology, while being consistent with current observations for \beta_0<1.6\times 10^{-3} \text{(95% CL)}. This work establishes the general framework to describe a non-comoving cosmology and extracts its first observational consequences for large-scale structure. Among the observable effects, we find sizeable modifications in the density-velocity and density-lensing potential cross-correlation spectra. These corrections give rise to deviations from statistical isotropy with a dipolar structure. The relative motion between the different fluids also couples the vector and scalar modes, the latter acting as sources for metric vector modes and vorticity for all the species.Comment: 50 pages, 12 figure

Constraints on anharmonic corrections of Fuzzy Dark Matter

The cold dark matter (CDM) scenario has proved successful in cosmology. However, we lack a fundamental understanding of its microscopic nature. Moreover, the apparent disagreement between CDM predictions and subgalactic-structure observations has prompted the debate about its behaviour at small scales. These problems could be alleviated if the dark matter is composed of ultralight fields $m \sim 10^{-22}\ \text{eV}$, usually known as fuzzy dark matter (FDM). Some specific models, with axion-like potentials, have been thoroughly studied and are collectively referred to as ultralight axions (ULAs) or axion-like particles (ALPs). In this work we consider anharmonic corrections to the mass term coming from a repulsive quartic self-interaction. Whenever this anharmonic term dominates, the field behaves as radiation instead of cold matter, modifying the time of matter-radiation equality. Additionally, even for high masses, i.e. masses that reproduce the cold matter behaviour, the presence of anharmonic terms introduce a cut-off in the matter power spectrum through its contribution to the sound speed. We analyze the model and derive constraints using a modified version of CLASS and comparing with CMB and large-scale structure data.Comment: 14 pages, 7 figure

Residual enzymatic activity as a prognostic factor in patients with Gaucher disease type 1: Correlation with Zimran and GAUSS-I index and the severity of bone disease

Background: Gaucher disease (GD) is an autosomal recessive disorder produced by mutations in the glucocerebrosidase gene (GBA), causing storage of glucosylceramide in reticuloendothelial cells in multiple organs. Traditionally, the prediction of the phenotype based on the genotype has been reported to be limited.Subjects and Methods: We investigated the correlation between the enzymatic residual activity (ERA) and the phenotype at diagnosis of the disease in 45 GD Spanish patients (44 with type I and 1 with type III GD). The genotype involved two of the following previously expressed proteins: c.517A¿>¿C (T134P), 1%; c.721G¿>¿A (G202R), 17%; c.1090G¿>¿T (G325W), 13.9%; c.1208G¿>¿A (S364N), 4.1%; c.1226A¿>¿G (N370S), 17.8%; c.1246G¿>¿A (G377S), 17.6%; c.1289C¿>¿T (P391L), 8.5%; c.1448T¿>¿C (L444P), 3%; and c.1504C¿>¿T (R463C), 24.5%. Recombinant alleles, deletion of 55¿bp in exon 9 and 84GG mutation were considered as mutations with no residual enzymatic activity.Results: The ERA showed a statistically significant correlation with chitotriosidase (P¿<¿0.001), age (P¿<¿0.001), spleen size (P¿<¿0.001), ‘Zimran’s Severity Score Index’ (P¿<¿0.01) and the ‘Gaucher Disease Severity Score Index—Type I’ (P¿<¿ 0.0001) at diagnosis of the disorder. Previous to any medical intervention, a comparison between the ERA and bone involvement, demonstrated a statistically significant relationship (P¿<¿0.01) between the two variables.Conclusions: This study data allowed us to define a new criterion for prognostic assessment of the disease at diagnosis, called Protein Severity Index, which expresses the theoretical severity of the genotype presented by patients, according to the corresponding ERA

High catalytic activity and pollutants resistivity using Fe-AAPyr cathode catalyst for microbial fuel cell application

© 2015, Macmillan Publishers Limited. All rights reserved. For the first time, a new generation of innovative non-platinum group metal catalysts based on iron and aminoantipyrine as precursor (Fe-AAPyr) has been utilized in a membraneless single-chamber microbial fuel cell (SCMFC) running on wastewater. Fe-AAPyr was used as an oxygen reduction catalyst in a passive gas-diffusion cathode and implemented in SCMFC design. This catalyst demonstrated better performance than platinum (Pt) during screening in "clean" conditions (PBS), and no degradation in performance during the operation in wastewater. The maximum power density generated by the SCMFC with Fe-AAPyr was 167±6μWcm-2 and remained stable over 16 days, while SCMFC with Pt decreased to 113±4μWcm-2 by day 13, achieving similar values of an activated carbon based cathode. The presence of S2- and SO42- showed insignificant decrease of ORR activity for the Fe-AAPyr. The reported results clearly demonstrate that Fe-AAPyr can be utilized in MFCs under the harsh conditions of wastewater

Cosmic evolution of FRI and FRII sources out to z=2.5

Radio-loud active galactic nuclei (RLAGN) play an important role in the evolution of galaxies through the effects on their environment. The two major morphological classes are core-bright (FRI) and edge-bright (FRII) sources. With the LOw-Frequency ARray (LOFAR) we compare the FRI and FRII evolution down to lower flux densities and with larger samples than before with the aim to examine the cosmic space density evolution for FRIs and FRIIs by analyzing their space density evolution between L_150~10^24.5 W/Hz and L_150~10^28.5 W/Hz and up to z=2.5. We construct radio luminosity functions (RLFs) from FRI and FRII catalogues based on recent data from LOFAR at 150MHz to study the space densities as a function of radio luminosity and redshift. To partly correct for selection biases and completeness, we simulate how sources appear at a range of redshifts. We report a space density enhancement from low to high redshift for FRI and FRII sources brighter than L_150~10^27 W/Hz. This is possibly related to the higher gas availability in the earlier denser universe. The constant FRI/FRII space density ratio evolution as a function of radio luminosity and redshift in our results suggests that the jet-disruption of FRIs might be primarily caused by events occurring on scales within the host galaxy, rather than being driven by changes in the overall large-scale environment. Remaining selection biases in our results also highlight the need to resolve more sources at angular scales below 40 arcsec and therefore strengthens the motivation for the further development and automation of the calibration and imaging pipeline of LOFAR data to produce images at sub-arcsecond resolution

Investigating rare haematological disorders - A celebration of 10 years of the Sherlock Holmes symposia

The Sherlock Holmes symposia have been educating haematologists on the need for prompt recognition, diagnosis and treatment of rare haematological diseases for 10 years. These symposia, which are supported by an unrestricted educational grant from Sanofi Genzyme, encourage haematologists to consider rare disorders in differential diagnoses. Improvement in rare disease awareness is important because diagnostics and the availability of effective therapies have improved considerably, meaning that rare haematological diseases can be accurately diagnosed and successfully managed, particularly if they are identified early. The Sherlock Holmes symposia programme includes real-life interactive clinical cases of rare haematological disorders that require awareness from the physician, to be diagnosed at an early stage. The audience are encouraged to examine each case as if they were detectives, look for clues from the clinical history and presentation, consider the potential causes, assess which tests would be required to make a definitive diagnosis and suggest optimal treatment options. To celebrate the 10-year anniversary of the Sherlock Holmes symposia, this article describes a number of clinical cases that include anaemia, thrombocytopaenia and splenomegaly among the presenting symptoms, to illustrate the importance of rigorous differential diagnosis in the identification of rare haematological disorders