Small-scale solar magnetic fields

As we resolve ever smaller structures in the solar atmosphere, it has become clear that magnetism is an important component of those small structures. Small-scale magnetism holds the key to many poorly understood facets of solar magnetism on all scales, such as the existence of a local dynamo, chromospheric heating, and flux emergence, to name a few. Here, we review our knowledge of small-scale photospheric fields, with particular emphasis on quiet-sun field, and discuss the implications of several results obtained recently using new instruments, as well as future prospects in this field of research.Comment: 43 pages, 18 figure

Dairy shows different associations with abdominal and BMI-defined overweight: cross-sectional analyses exploring a variety of dairy products

Background and aims: Previous studies suggest weight-regulatory properties for several dairy nutrients, but population-based studies on dairy and body weight are inconclusive. We explored cross-sectional associations between dairy consumption and indicators of overweight. Methods and results: We included 114 682 Dutch adults, aged ≥18y. Dairy consumption was quantified by a food frequency questionnaire. Abdominal overweight was defined as waist circumference (WC) ≥88 (women) or ≥102 (men) cm (n=37 391), overweight as BMI ≥25-30 kg/m2 (n=44 772), and obesity as BMI ≥30 kg/m2 (n=15 339). Associations were quantified by logistic (abdominal overweight, no/yes), multinomial logistic (BMI-defined overweight and obesity) and linear regression analyses (continuous measures of WC and BMI), and adjusted for relevant covariates. Total dairy was positively associated with abdominal overweight (OR Q1ref vs Q5: 1.09; 95% CI: 1.04, 1.14), and BMI-defined overweight (ORQ5 1.13; 95% CI: 1.08, 1.18) and obesity (ORQ5 1.09; 95% CI: 1.02, 1.16). Positive associations were also observed of skimmed, semi-skimmed, and non-fermented dairy with overweight categories. Full-fat dairy was inversely associated with overweight and obesity (ORQ5 for obesity: 0.78; 95% CI: 0.73, 0.83). Moreover, inverse associations were observed for yogurt and custard, and positive associations for milk, buttermilk, flavoured yogurt drinks, cheese, and cheese snacks. Fermented dairy, curd cheese and Dutch cheese were not consistently associated with overweight categories. Conclusions: Total, skimmed, semi-skimmed, and non-fermented dairy, milk, buttermilk, flavoured yogurt drinks, total cheese, and cheese snacks were positively associated with overweight categories, whereas full-fat dairy, custard, and yogurt were inversely associated with overweight categories

Evidence for multiple rhythmic skills

Rhythms, or patterns in time, play a vital role in both speech and music. Proficiency in a number of rhythm skills has been linked to language ability, suggesting that certain rhythmic processes in music and language rely on overlapping resources. However, a lack of understanding about how rhythm skills relate to each other has impeded progress in understanding how language relies on rhythm processing. In particular, it is unknown whether all rhythm skills are linked together, forming a single broad rhythmic competence, or whether there are multiple dissociable rhythm skills. We hypothesized that beat tapping and rhythm memory/sequencing form two separate clusters of rhythm skills. This hypothesis was tested with a battery of two beat tapping and two rhythm memory tests. Here we show that tapping to a metronome and the ability to adjust to a changing tempo while tapping to a metronome are related skills. The ability to remember rhythms and to drum along to repeating rhythmic sequences are also related. However, we found no relationship between beat tapping skills and rhythm memory skills. Thus, beat tapping and rhythm memory are dissociable rhythmic aptitudes. This discovery may inform future research disambiguating how distinct rhythm competencies track with specific language functions

APOE genotype influences insulin resistance, apolipoprotein CII and CIII according to plasma fatty acid profile in the Metabolic Syndrome

Metabolic markers associated with the Metabolic Syndrome (MetS) may be affected by interactions between the APOE genotype and plasma fatty acids (FA). In this study, we explored FA-gene interactions between the missense APOE polymorphisms and FA status on metabolic markers in MetS. Plasma FA, blood pressure, insulin sensitivity and lipid concentrations were determined at baseline and following a 12-week randomized, controlled, parallel, dietary FA intervention in 442 adults with MetS (LIPGENE study). FA-APOE gene interactions at baseline and following change in plasma FA were assessed using adjusted general linear models. At baseline E4 carriers had higher plasma concentrations of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (apo B) compared with E2 carriers; and higher TC, LDL-C and apo B compared with E3/E3. Whilst elevated plasma n-3 polyunsaturated FA (PUFA) was associated with a beneficially lower concentration of apo CIII in E2 carriers, a high proportion of plasma C16:0 was associated with insulin resistance in E4 carriers. Following FA intervention, a reduction in plasma long-chain n-3 PUFA was associated with a reduction in apo CII concentration in E2 carriers. Our novel data suggest that individuals with MetS may benefit from personalized dietary interventions based on APOE genotype

Solar constraints on new couplings between electromagnetism and gravity

The unification of quantum field theory and general relativity is a fundamental goal of modern physics. In many cases, theoretical efforts to achieve this goal introduce auxiliary gravitational fields, ones in addition to the familiar symmetric second-rank tensor potential of general relativity, and lead to nonmetric theories because of direct couplings between these auxiliary fields and matter. Here, we consider an example of a metric-affine gauge theory of gravity in which torsion couples nonminimally to the electromagnetic field. This coupling causes a phase difference to accumulate between different polarization states of light as they propagate through the metric-affine gravitational field. Solar spectropolarimetric observations are reported and used to set strong constraints on the relevant coupling constant k:k(2)\u3c (2.5 km)(2)

Temporal regularity of the environment drives time perception

It’s reasonable to assume that a regularly paced sequence should be perceived as regular, but here we show that perceived regularity depends on the context in which the sequence is embedded. We presented one group of participants with perceptually regularly paced sequences, and another group of participants with mostly irregularly paced sequences (75% irregular, 25% regular). The timing of the final stimulus in each sequence could be varied. In one experiment, we asked whether the last stimulus was regular or not. We found that participants exposed to an irregular environment frequently reported perfectly regularly paced stimuli to be irregular. In a second experiment, we asked participants to judge whether the final stimulus was presented before or after a flash. In this way, we were able to determine distortions in temporal perception as changes in the timing necessary for the sound and the flash to be perceived synchronous. We found that within a regular context, the perceived timing of deviant last stimuli changed so that the relative anisochrony appeared to be perceptually decreased. In the irregular context, the perceived timing of irregular stimuli following a regular sequence was not affected. These observations suggest that humans use temporal expectations to evaluate the regularity of sequences and that expectations are combined with sensory stimuli to adapt perceived timing to follow the statistics of the environment. Expectations can be seen as a-priori probabilities on which perceived timing of stimuli depend

Long slit Spectropolarimetry of Jupiter and Saturn

We present ground-based limb polarization measurements of Jupiter and Saturn consisting of full disk imaging polarimetry for the wavelength 7300 A and spatially resolved (long slit) spectropolarimetry covering the wavelength range 5200 to 9350 A. For the polar region of Jupiter we find for wl=6000 A a very strong radial polarization with a seeing corrected maximum of about +11.5% in the South and +10.0% in the North. Our model calculations demonstrate that the high limb polarization can be explained by strongly polarizing (p~1.0), high albedo (omega~0.98) haze particles with a scattering asymmetry parameter of g~0.6 as expected for aggregate particles. The deduced particle parameters are distinctively different when compared to lower latitude regions. The spectropolarimetry of Jupiter shows a decrease in the polar limb polarization towards longer wavelengths and a significantly enhanced polarization in strong methane bands when compared to the adjacent continuum. For lower latitudes the fractional polarization is small, negative, and it depends only little on wavelength except for the strong CH4-band at 8870 A. The South pole of Saturn shows a lower polarization (p~1.0-1.5%) than the poles of Jupiter. The spectropolarimetric signal for Saturn decrease rapidly with wavelength and shows no significant enhancements in the fractional polarization in the absorption bands. These properties can be explained by a vertically extended stratospheric haze region composed of small particles <100nm. In addition we find a previously not observed strong polarization feature (p=1.5-2.0%) near the equator of Saturn. The origin of this polarization signal is unclear but it could be related to a seasonal effect.Comment: Accepted for publication in ICARU

Financial Contracting with Tax Evaders

This paper derives the optimal financial contract when a borrowing entrepreneur can evade taxes in a model of costly state verification. In contrast to previous literature on costly state verification and financial contracting, we find that standard debt contracts are not optimal when tax evasion is possible. Instead, the optimal contract is debt-like only for very low and very high profit realizations, and features a constant repayment and verification of returns in an intermediate range. This occurs because the entrepreneur has to be given a positive rent even under verification in order to not abuse her limited liability protection for excessive tax evasion activities