The Heumann-Hotzel model for aging revisited

Since its proposition in 1995, the Heumann-Hotzel model has remained as an obscure model of biological aging. The main arguments used against it were its apparent inability to describe populations with many age intervals and its failure to prevent a population extinction when only deleterious mutations are present. We find that with a simple and minor change in the model these difficulties can be surmounted. Our numerical simulations show a plethora of interesting features: the catastrophic senescence, the Gompertz law and that postponing the reproduction increases the survival probability, as has already been experimentally confirmed for the Drosophila fly.Comment: 11 pages, 5 figures, to be published in Phys. Rev.

Homogeneous Fermion Superfluid with Unequal Spin Populations

For decades, the conventional view is that an s-wave BCS superfluid can not support uniform spin polarization due to a gap $\Delta$ in the quasiparticle excitation spectrum. We show that this is an artifact of the dismissal of quasiparticle interactions $V_{qp}^{}$ in the conventional approach at the outset. Such interactions can cause triplet fluctuations in the ground state and hence non-zero spin polarization at "magnetic field" $h<\Delta$. The resulting ground state is a pairing state of quasiparticles on the ``BCS vacuum". For sufficiently large $V_{qp}$, the spin polarization of at unitarity has the simple form $m\propto \mu^{1/2}$. Our study is motivated by the recent experiments at Rice which found evidence of a homogenous superfluid state with uniform spin polarization.Comment: 4 pages, 3 figure

The Unitary Gas and its Symmetry Properties

The physics of atomic quantum gases is currently taking advantage of a powerful tool, the possibility to fully adjust the interaction strength between atoms using a magnetically controlled Feshbach resonance. For fermions with two internal states, formally two opposite spin states, this allows to prepare long lived strongly interacting three-dimensional gases and to study the BEC-BCS crossover. Of particular interest along the BEC-BCS crossover is the so-called unitary gas, where the atomic interaction potential between the opposite spin states has virtually an infinite scattering length and a zero range. This unitary gas is the main subject of the present chapter: It has fascinating symmetry properties, from a simple scaling invariance, to a more subtle dynamical symmetry in an isotropic harmonic trap, which is linked to a separability of the N-body problem in hyperspherical coordinates. Other analytical results, valid over the whole BEC-BCS crossover, are presented, establishing a connection between three recently measured quantities, the tail of the momentum distribution, the short range part of the pair distribution function and the mean number of closed channel molecules.Comment: 63 pages, 8 figures. Contribution to the Springer Lecture Notes in Physics "BEC-BCS Crossover and the Unitary Fermi gas" edited by Wilhelm Zwerger. Revised version correcting a few typo

Subaru Studies of the Cosmic Dawn

An overview on the current status of the census of the early universe population is given. Observational surveys of high redshift objects provide direct opportunities to study the early epoch of the Universe. The target population included are Lyman Alpha Emitters (LAE), Lyman Break Galaxies (LBG), gravitationally lensed galaxies, quasars and gamma-ray bursts (GRB). The basic properties of these objects and the methods used to study them are reviewed. The present paper highlights the fact that the Subaru Telescope group made significant contributions in this field of science to elucidate the epoch of the cosmic dawn and to improve the understanding of how and when infant galaxies evolve into mature ones.Comment: 14 pages, 11 figures, accepted for publication in the Proceedings of the Japan Academy, Series

Planck 2018 results. IV. Diffuse component separation

We present full-sky maps of the cosmic microwave background (CMB) and polarized synchrotron and thermal dust emission, derived from the third set of Planck frequency maps. These products have significantly lower contamination from instrumental systematic effects than previous versions. The methodologies used to derive these maps follow closely those described in earlier papers, adopting four methods (Commander, NILC, SEVEM, and SMICA) to extract the CMB component, as well as three methods (Commander, GNILC, and SMICA) to extract astrophysical components. Our revised CMB temperature maps agree with corresponding products in the Planck 2015 delivery, whereas the polarization maps exhibit significantly lower large-scale power, reflecting the improved data processing described in companion papers; however, the noise properties of the resulting data products are complicated, and the best available end-to-end simulations exhibit relative biases with respect to the data at the few percent level. Using these maps, we are for the first time able to fit the spectral index of thermal dust independently over 3 degree regions. We derive a conservative estimate of the mean spectral index of polarized thermal dust emission of beta_d = 1.55 +/- 0.05, where the uncertainty marginalizes both over all known systematic uncertainties and different estimation techniques. For polarized synchrotron emission, we find a mean spectral index of beta_s = -3.1 +/- 0.1, consistent with previously reported measurements. We note that the current data processing does not allow for construction of unbiased single-bolometer maps, and this limits our ability to extract CO emission and correlated components. The foreground results for intensity derived in this paper therefore do not supersede corresponding Planck 2015 products. For polarization the new results supersede the corresponding 2015 products in all respects

Planck 2018 results. III. High Frequency Instrument data processing and frequency maps

This paper presents the High Frequency Instrument (HFI) data processing procedures for the Planck 2018 release. Major improvements in mapmaking have been achieved since the previous 2015 release. They enabled the first significant measurement of the reionization optical depth parameter using HFI data. This paper presents an extensive analysis of systematic effects, including the use of simulations to facilitate their removal and characterize the residuals. The polarized data, which presented a number of known problems in the 2015 Planck release, are very significantly improved. Calibration, based on the CMB dipole, is now extremely accurate and in the frequency range 100 to 353 GHz reduces intensity-to-polarization leakage caused by calibration mismatch. The Solar dipole direction has been determined in the three lowest HFI frequency channels to within one arc minute, and its amplitude has an absolute uncertainty smaller than $0.35\mu$K, an accuracy of order $10^{-4}$. This is a major legacy from the HFI for future CMB experiments. The removal of bandpass leakage has been improved by extracting the bandpass-mismatch coefficients for each detector as part of the mapmaking process; these values in turn improve the intensity maps. This is a major change in the philosophy of "frequency maps", which are now computed from single detector data, all adjusted to the same average bandpass response for the main foregrounds. Simulations reproduce very well the relative gain calibration of detectors, as well as drifts within a frequency induced by the residuals of the main systematic effect. Using these simulations, we measure and correct the small frequency calibration bias induced by this systematic effect at the $10^{-4}$ level. There is no detectable sign of a residual calibration bias between the first and second acoustic peaks in the CMB channels, at the $10^{-3}$ level

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Mortality reduction in yellowtail kingfish (Seriola lalandi) larval rearing by optimising Artemia feeding regimes

Mortality is a major concern in larval fish rearing during exogenous feeding. An important cause of mortality of larval yellowtail kingfish (Seriola lalandi) during the rotifer - Artemia weaning period was hypothesised as being due to larval sinking response after satiated feeding prior to dusk. This paper documents the effect of larval body density change under different Artemia feeding regimes and adds to the understanding of the cause of mortality of yellowtail kingfish larvae. The change in body density was used as a tool to determine the time of last feed in a day to ensure larvae were neutrally buoyant at dusk. An adaptive Artemia feeding regime was implemented, in which the amount of feed applied to the larvae was modified based on the body density. Larvae were denser than the seawater in which they were reared when fully satiated with Artemia. The time required to return to pre-feeding density significantly decreased with larval age. At 12days post hatch (dph), the peak in body density of larvae fed Artemia to satiation was 1.0320gcm -3 and they did not return to a pre-feeding body density (1.0260gcm -3), for approximately 10h. By 19dph, larval body density only increased to 1.0275gcm -3 when larvae were fully satiated and they were neutrally buoyant again by 4h. The decrease in larval body density when fully satiated at 16dph demonstrated that overfeeding larvae with Artemia should be avoided prior to dusk before this age to maintain neutral buoyancy. The use of the adaptive regime reduced mortality by 20% compared with the control, from 13 to 17dph, without sacrificing larval growth. Transition to Artemia feeding is a critical stage for yellowtail kingfish larvae and mortalities can be significantly reduced during this period by managing the timing of Artemia feeds throughout the day. The strategy of an adaptive feeding method may be considered a novel management tool to prevent larval sinking and associated mortality during the period of weaning from rotifers to Artemia during larval rearing

The performance of larval Seriola lalandi (Valenciennes, 1833) is affected by the taurine content of the Artemiaon which they are fed

This study describes the effects of feeding taurine-supplemented Artemia on the growth, survival, whole body taurine content and jaw malformation rate of larval yellowtail kingfish Seriola lalandi. Larvae were fed rotifers containing no supplemental taurine from 3 to 15 day post hatch (dph) and Artemia co-enriched with taurine from 12 to 22 dph. Artemia were supplemented at concentrations of either 0, 0.8, 1.6, 2.4, 3.2 or 4.0 g of taurine L-1 during the 18 h HUFA enrichment process. Taurine content in the Artemia increased from 0.76 ± 0.04% DW in those without supplementation to 3.95 ± 0.17% DW in those supplemented at 4.0 g L-1. Survival rates of larval yellowtail kingfish were significantly lower in all taurine-supplemented treatments compared to the unsupplemented control. Growth was significantly improved in those larvae fed taurine-supplemented Artemia; however, we cannot attribute this improvement solely to taurine, as improved growth may have been a function of the reduced survival, and therefore increased prey availability, in these treatments. The whole body taurine content of larvae fed unsupplemented Artemia was significantly lower (1.85 ± 0.03% DW) than those fed supplemented Artemia, which did not differ from each other (pooled average 2.48 ± 0.03% DW), suggesting either a functional excretion mechanism is in place or that this represents the saturation value for larvae of this age. Jaw malformation rates were not affected by Artemia taurine content. The results of this research suggest yellowtail kingfish larvae may have a lower requirement and/or a reduced tolerance to excess dietary taurine than juveniles

The effect of different rotifer feeding regimes on the growth and survival of yellowtail kingfish Seriola lalandi (Valenciennes, 1833) larvae

First feeding success is critical to larval marine finfish and optimization of live feed densities is important for larval performance and the economics of commercial hatchery production. This study investigated various rotifer feeding regimes on the prey consumption, growth and survival of yellowtail kingfish Seriola lalandi larvae over the first 12 days post hatch (dph). The common practice of maintaining high densities of rotifers (10-30 ind. mL-1) in the rearing tank was compared to a low density feeding technique, where 5-8 ind. mL-1 of rotifers were offered. A 'hybrid' feeding regime offered rotifers at the high density treatment until 5 dph and the lower feeding densities thereafter. There was no significant difference in larval survival (hybrid: 28.9 ± 7%, low density: 17.3 ± 5% and high density: 17.2 ± 9%) or growth (hybrid: 6.12 ± 0.18 mm, low density: 6.03 ± 0.10 mm and high density: 6.11 ± 0.23 mm) between treatments. Rotifer ingestion was independent of rotifer density throughout the trial and increased with larval age, with larvae at 4 dph ingesting 22 ± 1.5 rotifers larvae-1 h-1 and by 11 dph ingesting 59 ± 1.6 rotifers larvae-1 h-1. These data demonstrate that from first feeding, yellowtail kingfish larvae are efficient at capturing prey at the densities presented here and consequently significant savings in rotifer production costs as well as other potential benefits such as facilitation of early weaning and improved rotifer nutritional value may be obtained by utilizing lower density rotifer feeding regimes