A lower limit on the dark particle mass from dSphs

We use dwarf spheroidal galaxies as a tool to attempt to put precise lower limits on the mass of the dark matter particle, assuming it is a sterile neutrino. We begin by making cored dark halo fits to the line of sight velocity dispersions as a function of projected radius (taken from Walker et al. 2007) for six of the Milky Way's dwarf spheroidal galaxies. We test Osipkov-Merritt velocity anisotropy profiles, but find that no benefit is gained over constant velocity anisotropy. In contrast to previous attempts, we do not assume any relation between the stellar velocity dispersions and the dark matter ones, but instead we solve directly for the sterile neutrino velocity dispersion at all radii by using the equation of state for a partially degenerate neutrino gas (which ensures hydrostatic equilibrium of the sterile neutrino halo). This yields a 1:1 relation between the sterile neutrino density and velocity dispersion, and therefore gives us an accurate estimate of the Tremaine-Gunn limit at all radii. By varying the sterile neutrino particle mass, we locate the minimum mass for all six dwarf spheroidals such that the Tremaine-Gunn limit is not exceeded at any radius (in particular at the centre). We find sizeable differences between the ranges of feasible sterile neutrino particle mass for each dwarf, but interestingly there exists a small range 270-280eV which is consistent with all dSphs at the 1-$\sigma$ level.Comment: 13 pages, 2 figures, 1 tabl

Conical antiferromagnetic order in the ferroelectric phase of Mn0.8Co0.2WO4 resulting from the competition between collinear and cycloidal structures

Evolution of competing commensurate collinear (AF4) and incommensurate cycloidal (AF2) magnetic structures in Mn0.8Co0.2WO4 multiferroic was studied by neutron diffraction, magnetic, and pyroelectric characterization measurements. In contrast to pure and slightly Co doped MnWO4, the antiferromagnetic AF4 collinear phase [k1=(1/2,0,0)] inherent to the pure CoWO4 was observed below Néel temperature TN≈20 K in Mn0.8Co0.2WO4. This collinear order survives down to the lowest temperature reached in the experiments (2 K) even after the appearance of the second (cycloidal AF2) spin order below TFE≈8.5 K [k2=(−0.211,1/2,0.452)]. Ferroelectric polarization along b axis was revealed below TFE in the low temperature conical phase resulting from the superposition of the AF4 and AF2 spin structures. The arrangement of the spins after the two successive magnetic transitions are thoroughly described. In particular, we found that spins in the AF4 phase are aligned along the easy direction in the ac plane (∼142∘ with respect to the c* axis), while the cycloidal AF2 spin order is developed in the magnetically hard directions, perpendicular to the easy one, and consequently the TFE decreases compared to the pure MnWO4

Behaviour of the antioxidant tert-butylhydroquinone on the storage stability and corrosive character of biodiesel

AbstractThe behaviour of the antioxidant tert-butylhydroquinone (TBHQ) on the storage stability of biodiesel was investigated. Storage conditions were simulated through static immersion corrosion tests in biodiesel (with and without TBHQ) using copper coupons. Measurements of oxidation stability (Rancimat induction period) and metal release at different stages of corrosion were performed. After 24h of the static immersion test, the neat and TBHQ-doped biodiesels presented induction times below the EN 14214 limit (6h). Copper release was more intense in the neat biodiesel which evidenced that TBHQ retarded the corrosion process as a corrosion inhibitor. Ion trap–time-of-flight mass spectrometry (IT–TOF-MS) revealed the presence of considerable amounts of tert-butylquinone (TBQ) in the TBHQ-doped biodiesel exposed to the corrosion process. As TBHQ molecules adsorb at the copper surface to inhibit corrosion, these molecules are catalytically oxidised to TBQ. IT–TOF-MS also indicated the formation of new molecules of high molecular weight only presented in the TBHQ-doped biodiesel deteriorated by the corrosion process. MS2 spectra gave clear evidence of the formation of new complexes between free radicals of long-chain molecules (fatty acid derivatives) and TBQ radicals during biodiesel deterioration

Detrital zircon typology and U/Pb geochronology for the Miocene Ladrilleros-Juanchaco sedimentary sequence, Equatorial Pacific (Colombia) : new constraints on provenance and paleogeography in northwestern South America

Typology and internal texture analyses were performed on detrital zircons obtained from the Miocene sandstones of the Ladrilleros-Juanchaco sedimentary sequence (Colombia, Equatorial Pacific). This analysis was complemented with zircon U/Pb dating to identify typology-age associations as indicators of provenance of these sediments. Our results show that zircons with S and P dominant typology have internal structures/zoning that indicate mostly igneous and possibly some metamorphic origins. Morphometric results suggest little transport from source areas. Both typology and U/Pb data point to the Western Cordillera as the main source of the detrital materials of this sedimentary sequence. A paleogeographic reconstruction shows that during Late Miocene times there were significant portions of the Western Cordillera uplifted, eroding away and acting as a fluvio-topographic barrier blocking sediments from the Central Cordillera to reach the Pacific basins. Miocene plutons at the axis of the Western Cordillera were also probably exhumed and played a role as geomorphologically active massifs. This study demonstrates that typologic analysis on detrital zircon grains is a powerful tool as indicator of provenance and paleogeography in complex litho-tectonic areas where overlapping U/Pb signatures can lead to contradictory results

Effectiveness of mobile telemonitoring applications in heart failure patients: systematic review of literature and meta-analysis

Q2Q1Pacientes con Insuficiencia cardiacaClose and frequent follow-up of heart failure (HF) patients improves clinical outcomes. Mobile telemonitoring applications are advantageous alternatives due to their wide availability, portability, low cost, computing power, and interconnectivity. This study aims to evaluate the impact of telemonitoring apps on mortality, hospitalization, and quality of life (QoL) in HF patients. We conducted a registered (PROSPERO CRD42022299516) systematic review of randomized clinical trials (RCTs) evaluating mobile-based telemonitoring strategies in patients with HF, published between January 2000 and December 2021 in 4 databases (PubMed, EMBASE, BVSalud/LILACS, Cochrane Reviews). We assessed the risk of bias using the RoB2 tool. The outcome of interest was the effect on mortality, hospitalization risk, and/or QoL. We performed meta-analysis when appropriate; heterogeneity and risk of publication bias were evaluated. Otherwise, descriptive analyses are offered. We screened 900 references and 19 RCTs were included for review. The risk of bias for mortality and hospitalization was mostly low, whereas for QoL was high. We observed a reduced risk of hospitalization due to HF with the use of mobile-based telemonitoring strategies (RR 0.77 [0.67; 0.89]; I2 7%). Non-statistically significant reduction in mortality risk was observed. The impact on QoL was variable between studies, with different scores and reporting measures used, thus limiting data pooling. The use of mobile-based telemonitoring strategies in patients with HF reduces risk of hospitalization due to HF. As smartphones and wirelessly connected devices are increasingly available, further research on this topic is warranted, particularly in the foundational therapy.https://orcid.org/0000-0002-4189-4317https://orcid.org/0000-0002-8244-2958https://orcid.org/0000-0001-5401-0018https://orcid.org/0000-0003-1490-1822https://orcid.org/0000-0002-3606-2102Revista Internacional - IndexadaA1N

On the exploitation of serendipity in drug discovery

We have written previously about the nature of serendipity and the role that it played in the “Psychopharmacology Revolution” of the 1950s and 1960s [1-3]. However, we have not previously addressed the issue of whether it is possible or desirable to design studies to enhance and exploit serendipity. We do so here. First, it is essential to establish a definition of serendipity. As we suggested previously [1], the term serendipity shall be defined as “the discovery of something not sought”. This definition, like most others, requires the element of sagacity. The observation of “something not sought” will not lead to discovery unless someone has the mental discernment (sagacity) required to recognize that the observation has significance. However, sagacity cannot be used to differentiate serendipitous from non-serendipitous discoveries because it is a necessary attribute of both. Sagacity and discovery are synonyms in this contex

Chemoarchaeological downsizing in a hierarchical universe: impact of a top-heavy IGIMF

We make use of a semi-analytical model of galaxy formation to investigate the origin of the observed correlation between [α/Fe] abundance ratios and stellar mass in elliptical galaxies.We implement a new galaxy-wide stellar initial mass function (IMF; top-heavy integrated galaxy initial mass function, TH-IGIMF) in the semi-analytic model SAG (acronym for semi-analytic galaxies) and evaluate its impact on the chemical evolution of galaxies. The star formation rate (SFR) dependence of the slope of the TH-IGIMF is found to be key to reproducing the correct [α/Fe]-stellar mass relation. Massive galaxies reach higher [α/Fe] abundance ratios because they are characterized by more top-heavy IMFs as a result of their higher SFR. As a consequence of our analysis, the value of the minimum embedded star cluster mass and of the slope of the embedded cluster mass function, which are free parameters involved in the TH-IGIMF theory, are found to be as lowas 5 and 2M⊙, respectively. Amild downsizing trend is present for galaxies generated assuming either a universal IMF or a variable TH-IGIMF.We find that, regardless of galaxy mass, older galaxies (with formation redshifts ≳2) are formed in shorter time-scales (≲2 Gyr), thus achieving larger [α/Fe] values. Hence, the time-scale of galaxy formation alone cannot explain the slope of the [α/Fe]-galaxy mass relation, but is responsible for the big dispersion of [α/Fe] abundance ratios at fixed stellar mass. We further test the hypothesis of a TH-IGIMF in elliptical galaxies by looking into mass-to-light ratios, and luminosity functions. Models with a TH-IGIMF are also favoured by these constraints. In particular, mass-to-light ratios agree with observed values for massive galaxies while being overpredicted for less massive ones; this overprediction is present regardless of the IMF considered.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísica

Neutron diffraction, magnetic, and magnetoelectric studies of phase transitions in multiferroic Mn0.90Co0.10WO4

We have studied various spontaneous and magnetic-field-induced phase transitions in single crystals of multiferroic Mn0.9Co0.1WO4 using magnetic and magnetoelectric measurements and neutron diffraction. Compared to pure MnWO4, our data consistently confirm that the anisotropic Co2+ ions induce reorientation of the spin cycloid structure to the ac plane and reveal Pa and Pc components of spontaneous electric polarization.Field-induced phase transitions accompanied by anomalies of magnetic susceptibility and suppression of both Pa and Pc polarizations have been observed for H∥c (∼3 T) and H∥a (∼8.5 T). Neutron diffraction has revealed that in both cases the spin cycloid plane flops in direction almost perpendicular to H, i.e., close to the ab and bc planes, respectively. Parameters describing the magnetic structures including wave vectors, orientations of the main elliptical axes, etc., have been determined in all spontaneous and field-induced states

Evolution of Phenolic Content, Antioxidant Capacity and Phenolic Profile during Cold Pre-fermentative Maceration and Subsequent Fermentation of Cabernet Sauvignon Red Wine

The phenolic compound profile and content of red wines are modified during the maceration-fermentation process by several factors that alter the extractability of the compounds and by reactions that phenolic compounds undergo, and can be directly related to the quality of the final wine and its beneficial effects on the consumer. The aim of this study was to determine the change in phenolic content and profile during cold pre-fermentative maceration and fermentation without the removal of grape pomace. Total phenolics,flavonoids, anthocyanins, tannins and antioxidant capacity were determined by spectrophotometric methods, and the phenolic profile was determined by HPLC-MS on each day of the maceration-fermentation process. The results showed a variation in the content of phenolic compounds and antioxidant activity over time, but the final phenolic content showed no significative difference compared with the initial content (1 268 mg GAE/L and 1 115 mg GAE/L respectively). The phenolic profile showed that flavonoids were theprincipal compounds in wine and that they increased at the end of the winemaking. Condensed tannins also increased during fermentation, while anthocyanins and some phenolic acids decreased at the end of the process. The final content of phenolic compounds was similar to the initial one, but there was a change in the different fractions of phenolic compounds at the end of fermentation

Extended WKB method, resonances and supersymmetric radial barriers

Semiclassical approximations are implemented in the calculation of position and width of low energy resonances for radial barriers. The numerical integrations are delimited by t/T<<8, with t the period of a classical particle in the barrier trap and T the resonance lifetime. These energies are used in the construction of `haired' short range potentials as the supersymmetric partners of a given radial barrier. The new potentials could be useful in the study of the transient phenomena which give rise to the Moshinsky's diffraction in time.Comment: 12 pages, 4 figures, 3 table