Context.
The production of neutrinos by plasma oscillations is the most important energy sink process operating in the degenerate core of low-mass red giant stars. This process counterbalances the ...release of energy induced by nuclear reactions and gravitational contraction, and determines the luminosity attained by a star at the moment of the He ignition. This occurrence coincides with the tip of the red giant branch (RGB), whose luminosity is extensively used as a calibrated standard candle in several cosmological studies.
Aims.
We aim to investigate the possible activation of additional energy sink mechanisms, as predicted by many extensions of the so-called Standard Model. In particular, our objective is to test the possible production of axions or axion-like particles, mainly through their coupling with electrons.
Methods.
By combining
Hubble
Space Telescope and ground-based optical and near-infrared photometric samples, we derived the RGB tip absolute magnitude of 22 galactic globular clusters (GGCs). The effects of varying the distance and the metallicity scales were also investigated. Then we compared the observed tip luminosities with those predicted by state-of-the-art stellar models that include the energy loss due to the axion production in the degenerate core of red giant stars.
Results.
We find that theoretical predictions including only the energy loss by plasma neutrinos are, in general, in good agreement with the observed tip bolometric magnitudes, even though the latter are ∼0.04 mag brighter on average. This small shift may be the result of systematic errors affecting the evaluation of the RGB tip bolometric magnitudes, or, alternatively, it could be ascribed to an axion-electron coupling causing a non-negligible thermal production of axions. In order to estimate the strength of this possible axion sink, we performed a cumulative likelihood analysis using the RGB tips of the whole set of 22 GGCs. All the possible sources of uncertainties affecting both the measured bolometric magnitudes and the corresponding theoretical predictions were carefully considered. As a result, we find that the value of the axion-electron coupling parameter that maximizes the likelihood probability is
g
ae
/10
−13
∼ 0.60
−0.58
+0.32
. This hint is valid, however, if the dominant energy sinks operating in the core of red giant stars are standard neutrinos and axions coupled with electrons. Any additional energy-loss process, not included in the stellar models, would reduce such a hint. Nevertheless, we find that values
g
ae
/10
−13
> 1.48 can be excluded with 95% confidence.
Conclusions.
The new bound we find represents the most stringent constraint for the axion-electron coupling available so far. The new scenario that emerges after this work represents a greater challenge for future experimental axion searches. In particular, we can exclude that the recent signal seen by the XENON1T experiment was due to solar axions.
Quantum dots (QDs) are semiconductor nanoparticles with unique optical and electronic properties, whose interest as potential nano-theranostic platforms for imaging and sensing is increasing. The ...design and use of QDs requires the understanding of cell-nanoparticle interactions at a microscopic and nanoscale level. Model systems such as supported lipid bilayers (SLBs) are useful, less complex platforms mimicking physico-chemical properties of cell membranes. In this work, we investigated the effect of topographical homogeneity of SLBs bearing different surface charge in the adsorption of hydrophilic QDs. Using quartz-crystal microbalance, a label-free surface sensitive technique, we show significant differences in the interactions of QDs onto homogeneous and inhomogeneous SLBs formed following different strategies. Within short time scales, QDs adsorb onto topographically homogeneous, defect-free SLBs is driven by electrostatic interactions, leading to no layer disruption. After prolonged QD exposure, the nanomechanical stability of the SLB decreases suggesting nanoparticle insertion. In the case of inhomogeneous, defect containing layers, QDs target preferentially membrane defects, driven by a subtle interplay of electrostatic and entropic effects, inducing local vesicle rupture and QD insertion at membrane edges.
Display omitted
•Electrostatic interactions drive QDs adsorption onto defect-free supported lipid bilayers.•QDs exposure time leads to a decrease of the membrane nanomechanical stability.•QDs adsorption is stronger on defect containing membranes than on defect-free.•QDs target preferentially membrane defects.
In a Galactic core-collapse supernova (SN), axionlike particles (ALPs) could be emitted via the Primakoff process and eventually convert into γ rays in the magnetic field of the Milky Way. From a ...data-driven sensitivity estimate, we find that, for a SN exploding in our Galaxy, the Fermi Large Area Telescope (LAT) would be able to explore the photon-ALP coupling down to g_{aγ}≃2×10^{-13} GeV^{-1} for an ALP mass m_{a}≲10^{-9} eV. These values are out of reach of next generation laboratory experiments. In this event, the Fermi LAT would probe large regions of the ALP parameter space invoked to explain the anomalous transparency of the Universe to γ rays, stellar cooling anomalies, and cold dark matter. If no γ-ray emission were to be detected, Fermi-LAT observations would improve current bounds derived from SN 1987A by more than 1 order of magnitude.
To assess if received professional and social support are associated with father-infant bonding among primiparous (first-time) and multiparous (multi-time) fathers.
Early father-infant bonding ...predicts several positive child outcomes. However, while received professional and social support positively impacts fathers’ transition into parenthood, little research has tested if these factors are associated with a stronger father-infant bond.
In total, 499 fathers (296 primiparous and 203 multiparous) of infants (aged 0–12 months) completed a cross-sectional online survey between November 2018 and March 2020. The survey included items related to socio-demographics, having a planned pregnancy, postnatal midwifery support, child health nurse support, child health center attendance, and social support. The parent-infant bonding questionnaire (PBQ) was used to assess the father-infant bond. Multiple linear regression models were estimated for the total sample and based on paternal parity. Missing data were managed through multiple imputation procedures.
Fathers reported fewer bonding disturbances if they received support from their partners, postnatal midwives, child health nurses, and attended more child health visits. Primiparous fathers reported fewer bonding disturbances when receiving support from their partners, postnatal midwives, and the child health nurse. However, multiparous fathers had more bonding disturbances than primiparous fathers and received less professional and partner support.
Receiving more partner and professional support is associated with less father-infant bonding disturbances. To encourage a better father-infant bond, clinicians should invite and support all fathers, regardless of parity, as they transition to parenthood.
Questionnaires for the screening of paternal perinatal psychological distress are based on clinical manifestations expressed by women, showing limitations in capturing the wide array of signs and ...symptoms exhibited by men. The current study aimed to validate the Perinatal Assessment of Paternal Affectivity, a new self-report tool for the screening of paternal depressive and affective disorder.
This study used a cross-sectional design with a 3-month test-retest, involving respectively 385 (T1) and a sub-sample of 111(T2) fathers. Confirmatory factor analysis (CFA) was performed to test structural validity and concurrent validity was assessed by Spearman correlations. We assessed reliability using McDonald's ω and ordinal alpha. Group differences in PAPA scores based on sociodemographic were also tested.
The CFA reported a one factor structure as the optimal solution. The PAPA also showed adequate reliability and internal consistency as well as acceptable test–retest indices. Concurrent validity was confirmed by significant correlations between PAPA total score and standardized test scores. Non-Italian fathers and fathers who experienced recent stressful life events reported higher PAPA scores.
Our sample was not homogeneous in terms of nationality and most of the participants, were from Northern Italy. Some risk factors associated with paternal parental psychological distress (e.g., unplanned pregnancy) have not been considered.
This study provides initial evidence of validity and reliability of the PAPA as a brief and sensitive screening tool to detect signs and symptoms of paternal affective disorder during both prenatal and postnatal period.
•Perinatal psychological distress in men can be displayed through a wide array of symptoms.•The PAPA is a new self-report tool for the screening of perinatal affective disorder in fathers.•The PAPA showed a one factor structure, adequate validity, and internal consistency.•Three months test-retest revealed a moderate temporal stability.•The PAPA is useful and simple tool for the screening of at-risk fathers.
Abstract Dark (hidden) photons are widely recognised as well motivated candidates for physics beyond the standard model, and have been invoked for the solution of several outstanding problems, ...including to account for the dark matter in the universe. In this paper, we consider a simple model for dark photons, which is coupled to ordinary matter only through kinetic mixing with ordinary photons. Within this framework, we calculate the flux of solar dark photons on Earth and revise the potential to detect it with the next generation of axion helioscopes, particularly with the International AXion Observatory (IAXO). This paper extends on previous theoretical analyses in two main ways. Firstly, it includes a more complete analysis of the possible sources of dark photons from the sun, including the contribution of the solar magnetic field and of nuclear processes, and secondly it includes predictions on the parameter space accessible in the gas-filled phase of IAXO.
Purpose
Early detection of cardiac arrhythmias is a major opportunity for mobile health, as wearable devices nowadays available can detect single-lead electrocardiogram (ECG). The study aims to ...validate the in-ear region as a new anatomical site for ECG signal detection and looks towards designing innovative ECG wearable devices.
Methods
We performed ECG using KardiaMobile device (AliveCor®) on 35 healthy volunteers. First, ECG was detected by standard modality using both hands. Then, ECG was detected using the left in-ear region instead of the right hand. All the recorded ECGs were analyzed by the device and by two cardiologists in blind testing.
Results
We successfully collected 70 ECGs performed on 35 volunteers (male 54%, age 39.1 ± 10.7 years; BMI 22.9 ± 2.89 kg/m
2
) with no differences observed by KardiaMobile in ECG reports detected in the two different modalities. All the ECGs were reported as normal by the device and the two cardiologists. Moreover, linear regression analysis showed good correlation between the amplitude (mV) of P (
r
= 0.76;
r
2
= 0.57;
p
< 0.0001) and QRS waves (
r
= 0.81;
r
2
= 0.65;
p
< 0.0001), the intervals (ms) of PR (
r
= 0.91;
r
2
= 0.83;
p
< 0.0001; LOA − 0.60–0.41; CC = 0.91), QRS (
r
= 0.78;
r
2
= 0.61;
p
< 0.0001; LOA − 0.49–0.43; CC = 0.78), QT (
r
= 0.85;
r
2
= 0.71;
p
< 0.0001; LOA − 1.31–1.20; CC = 0.85), and heart rate (
r
= 0.94;
r
2
= 0.89;
p
< 0.0001; LOA − 7.82–7.76; CC = 0.94) detected in two different modalities.
Conclusion
The in-ear region is a reliable novel anatomical site for ECG signal detection in normal healthy subjects. Further studies are needed to validate this new ECG detection modality also in case of cardiac arrhythmias and to support the development of new wearable devices.
The first steps of nickel electrodeposition in a deep eutectic solvent (DES) are analyzed in detail. Several substrates from glassy carbon to Pt(111) were investigated pointing out the surface ...sensitivity of the nucleation and growth mechanism. For that, cyclic voltammetry and chronoamperometry, in combination with scanning electron microscopy (SEM), were employed. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to more deeply analyze the Ni deposition on Pt substrates. In a 0.1 M NiCl2 + DES solution (at 70 °C), the nickel deposition on glassy carbon takes place within the potential limits of the electrode in the blank solution. Although, the electrochemical window of Pt|DES is considerably shorter than on glassy carbon|DES, it was still sufficient for the nickel deposition. On the Pt electrode, the negative potential limit was enlarged while the nickel deposit grew, likely because of the lower catalytic activity of the nickel toward the reduction of the DES. At lower overpotentials, different hydrogenated Ni structures were favored, most likely because of the DES co-reduction on the Pt substrate. Nanometric metallic nickel grains of rounded shape were obtained on any substrate, as evidenced by the FE-SEM. Passivation phenomena, related to the formation of Ni oxide and Ni hydroxylated species, were observed at high applied overpotentials. At low deposited charge, on Pt(111) the AFM measurements showed the formation of rounded nanometric particles of Ni, which rearranged and formed small triangular arrays at sufficiently low applied overpotential. This particle pattern was induced by the ⟨111⟩ orientation and related to surface sensitivity of the nickel deposition in DES. The present work provides deep insights into the Ni electrodeposition mechanism in the selected deep eutectic solvent.
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