We use state-of-the-art measurements of the galaxy luminosity function (LF) at z=6, 7, and 8 to derive constraints on warm dark matter (WDM), late-forming dark matter, and ultralight axion dark ...matter models alternative to the cold dark matter (CDM) paradigm. To this purpose, we have run a suite of high-resolution N-body simulations to accurately characterize the low-mass end of the halo mass function and derive dark matter (DM) model predictions of the high-z luminosity function. In order to convert halo masses into UV magnitudes, we introduce an empirical approach based on halo abundance matching, which allows us to model the LF in terms of the amplitude and scatter of the ensemble average star formation rate halo mass relation, ⟨SFR(Mh,z)⟩, of each DM model. We find that, independent of the DM scenario, the average SFR at fixed halo mass increases from z=6 to 8, while the scatter remains constant. At halo mass Mh≳1012 M h−1, the average SFR as a function of halo mass follows a double power law trend that is common to all models, while differences occur at smaller masses. In particular, we find that models with a suppressed low-mass halo abundance exhibit higher SFR compared to the CDM results. Thus, different DM models predict a different faint-end slope of the LF which causes the goodness of fit to vary within each DM scenario for different model parameters. Using deviance statistics, we obtain a lower limit on the WDM thermal relic particle mass, mWDM≳1.5 keV at 2σ. In the case of LFDM models, the phase transition redshift parameter is bounded to zt≳8×105 at 2σ. We find ultralight axion dark matter best-fit models with axion mass ma≳1.6×10−22 eV to be well within 2σ of the deviance statistics. We remark that measurements at z=6 slightly favor a flattening of the LF at faint UV magnitudes. This tends to prefer some of the non-CDM models in our simulation suite, although not at a statistically significant level to distinguish them from CDM.
Ghrelin, a stomach-derived orexigenic hormone, has stimulated great interest as a potential target for obesity control. Pharmacological evidence indicates that ghrelin’s effects on food intake are ...mediated by neuropeptide Y (NPY) and agouti-related protein (AgRP) in the central nervous system. These include intracerebroventricular application of antibodies to neutralize NPY and AgRP, and the application of an NPY Y1 receptor antagonist, which blocks some of the orexigenic effects of ghrelin. Here we describe treatment of Agrp−/−;Npy−/− and Mc3r−/−;Mc4r−/− double knockout mice as well as Npy−/− and Agrp−/− single knockout mice with either ghrelin or an orally active nonpeptide ghrelin agonist. The data demonstrate that NPY and AgRP are required for the orexigenic effects of ghrelin, as well as the involvement of the melanocortin pathway in ghrelin signaling. Our results outline a functional interaction between the NPY and AgRP pathways. Although deletion of either NPY or AgRP caused only a modest or nondetectable effect, ablation of both ligands completely abolished the orexigenic action of ghrelin. Our results establish an in vivo orexigenic function for NPY and AgRP, mediating the effect of ghrelin.
The Two Micron All Sky Survey (2MASS) Skrutskie, M. F; Cutri, R. M; Stiening, R ...
The Astronomical journal,
02/2006, Letnik:
131, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Between 1997 June and 2001 February the Two Micron All Sky Survey (2MASS) collected 25.4 Tbytes of raw imaging data covering 99.998% of the celestial sphere in the near-infrared J (1.25 mm), H (1.65 ...mm), and Ks (2.16 mm) bandpasses. Observations were conducted from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona, and Cerro Tololo, Chile. The 7.8 s of integration time accumulated for each point on the sky and strict quality control yielded a 10 s point-source detection level of better than 15.8, 15.1, and 14.3 mag at the J, H, and Ks bands, respectively, for virtually the entire sky. Bright source extractions have 1 s photometric uncertainty of <0.03 mag and astrometric accuracy of order 100 mas. Calibration offsets between any two points in the sky are <0.02 mag. The 2MASS All-Sky Data Release includes 4.1 million compressed FITS images covering the entire sky, 471 million source extractions in a Point Source Catalog, and 1.6 million objects identified as extended in an Extended Source Catalog.
We report on a search for ultralow-mass axionlike dark matter by analyzing the ratio of the spin-precession frequencies of stored ultracold neutrons and Hg199 atoms for an axion-induced oscillating ...electric dipole moment of the neutron and an axion-wind spin-precession effect. No signal consistent with dark matter is observed for the axion mass range 10−24≤ma≤10−17eV . Our null result sets the first laboratory constraints on the coupling of axion dark matter to gluons, which improve on astrophysical limits by up to 3 orders of magnitude, and also improves on previous laboratory constraints on the axion coupling to nucleons by up to a factor of 40.
The hyperpolymorphic HLA genes play important roles in disease and transplantation and act as genetic markers of migration and evolution. A panel of 107 B‐lymphoblastoid cell lines (B‐LCLs) was ...established in 1987 at the 10th International Histocompatibility Workshop as a resource for the immunogenetics community. These B‐LCLs are well characterised and represent diverse ethnicities and HLA haplotypes. Here we have applied Pacific Biosciences’ Single Molecule Real‐Time (SMRT) DNA sequencing to HLA type 126 B‐LCL, including the 107 International HLA and Immunogenetics Workshop (IHIW) cells, to ultra‐high resolution. Amplicon sequencing of full‐length HLA class I genes (HLA‐A, ‐B and ‐C) and partial length HLA class II genes (HLA‐DRB1, ‐DQB1 and ‐DPB1) was performed. We typed a total of 931 HLA alleles, 895 (96%) of which were consistent with the typing in the IPD‐IMGT/HLA Database (Release 3.27.0, January 20, 2017), with 595 (64%) typed at a higher resolution. Discrepant types, including novel alleles (n = 10) and changes in zygosity (n = 13), as well as previously unreported types (n = 34) were observed. In addition, patterns of linkage disequilibrium were distinguished by four‐field resolution typing of HLA‐B and HLA‐C. By improving and standardising the HLA typing of these B‐LCLs, we have ensured their continued usefulness as a resource for the immunogenetics community in the age of next generation DNA sequencing.
The atomic nucleus and its electrons are often thought of as independent systems that are held together in the atom by their mutual attraction. Their interaction, however, leads to other important ...effects, such as providing an additional decay mode for excited nuclear states, whereby the nucleus releases energy by ejecting an atomic electron instead of by emitting a γ-ray. This 'internal conversion' has been known for about a hundred years and can be used to study nuclei and their interaction with their electrons. In the inverse process-nuclear excitation by electron capture (NEEC)-a free electron is captured into an atomic vacancy and can excite the nucleus to a higher-energy state, provided that the kinetic energy of the free electron plus the magnitude of its binding energy once captured matches the nuclear energy difference between the two states. NEEC was predicted in 1976 and has not hitherto been observed. Here we report evidence of NEEC in molybdenum-93 and determine the probability and cross-section for the process in a beam-based experimental scenario. Our results provide a standard for the assessment of theoretical models relevant to NEEC, which predict cross-sections that span many orders of magnitude. The greatest practical effect of the NEEC process may be on the survival of nuclei in stellar environments, in which it could excite isomers (that is, long-lived nuclear states) to shorter-lived states. Such excitations may reduce the abundance of the isotope after its production. This is an example of 'isomer depletion', which has been investigated previously through other reactions, but is used here to obtain evidence for NEEC.
ULTRACAM is a portable, high-speed imaging photometer designed to study faint astronomical objects at high temporal resolutions. ULTRACAM employs two dichroic beamsplitters and three frame-transfer ...CCD cameras to provide three-colour optical imaging at frame rates of up to 500 Hz. The instrument has been mounted on both the 4.2-m William Herschel Telescope on La Palma and the 8.2-m Very Large Telescope in Chile, and has been used to study white dwarfs, brown dwarfs, pulsars, black hole/neutron star X-ray binaries, gamma-ray bursts, cataclysmic variables, eclipsing binary stars, extrasolar planets, flare stars, ultracompact binaries, active galactic nuclei, asteroseismology and occultations by Solar System objects (Titan, Pluto and Kuiper Belt objects). In this paper we describe the scientific motivation behind ULTRACAM, present an outline of its design and report on its measured performance.
Abstract
Objective
Our primary objective was to evaluate how the Indigenous Healing and Seeking Safety (IHSS) model impacted residential addiction treatment program completion rates. Our secondary ...objective was to evaluate health service use 6 months before and 6 months after residential treatment for clients who attended the program before and after implementing IHSS.
Methods
We observed clients of the Benbowopka Residential Treatment before IHSS implementation (from April 2013 to March 31, 2016) and after IHSS implementation (from January 1, 2018 – March 31, 2020). The program data were linked to health administration data, including the Ontario Health Insurance Plan (OHIP) physician billing, the Registered Persons Database (RPDB), the National Ambulatory Care Reporting System (NACRS), and the Discharge Abstract Database (DAD). Chi-square tests were used to compare patient characteristics in the no-IHSS and IHSS groups. We used logistic regression to estimate the association between IHSS and treatment completion. We used generalized estimating equation (GEE) regression model to evaluate health service use (including primary care visits, ED visits overall and for substance use, hospitalizations and mental health visits), Results: There were 266 patients in the no-IHSS group and 136 in the IHSS group. After adjusting for individual characteristics, we observed that IHSS was associated with increased program completion rates (odds ratio = 1.95, 95% CI 1.02-3.70). There was no significant association between IHSS patients’ health service use at time one or time two. Primary care visits time 1: aOR 0.55, 95%CI 0.72-1.13, time 2: aOR 1.13, 95%CI 0.79-1.23; ED visits overall time 1: aOR 0.91, 95%CI 0.67-1.23, time 2: aOR 1.06, 95%CI 0.75-1.50; ED visits for substance use time 1: aOR 0.81, 95%CI 0.47-1.39, time 2: aOR 0.79, 95%CI 0.37-1.54; Hospitalizations time 1: aOR 0.78, 95%CI 0.41-1.47, time 2: aOR 0.76, 95%CI 0.32-1.80; Mental health visits time 1: aOR 0.66, 95%CI 0.46-0.96, time 2: aOR 0.92 95%CI 0.7-1.40.
Conclusions
Our results indicate that IHSS positively influenced program completion but had no significant effect on health service use.
Trial registration
This study was registered with clinicaltrials.gov (identifier number NCT04604574). First registration 10/27/2020.
Summary
Background
There is limited understanding of how maternal diet affects breastmilk food allergen concentrations, and whether exposure to allergens through this route influences the development ...of infant oral tolerance or sensitization.
Objective
To investigate how maternal dietary egg ingestion during early lactation influences egg protein (ovalbumin) levels detected in human breastmilk.
Methods
In a randomized controlled trial, women were allocated to a dietary group for the first six weeks of lactation: high‐egg diet (> 4 eggs per week), low‐egg diet (one‐three eggs per week) or an egg‐free diet. Breastmilk samples were collected at 2, 4 and 6 weeks of lactation for the measurement of ovalbumin. The permeability of the mammary epithelium was assessed by measuring the breastmilk sodium : potassium ratio. Egg‐specific IgE and IgG4 were measured in infant plasma at 6 weeks, and prior to the introduction of egg in solids at 16 weeks.
Results
Average maternal egg ingestion was associated with breastmilk ovalbumin concentration. Specifically, for each additional egg ingested per week, there was an average 25% increase in ovalbumin concentration (95% CI: 5–48%, P = 0.01). Breastmilk ovalbumin concentrations were significantly higher in the ‘high‐egg’ group (> 4 eggs per week) compared with the ‘egg‐free’ group (P = 0.04). However, one‐third of women had no breastmilk ovalbumin detected. No detectable associations were found between mammary epithelium permeability and breastmilk ovalbumin concentrations. Infant plasma egg‐specific IgG4 levels were also positively associated with maternal egg ingestion, with an average 22% (95% CI: 3–45%) increase in infant egg‐specific IgG4 levels per additional egg consumed per week (P = 0.02).
Conclusions and Clinical Relevance
Increased maternal egg ingestion is associated with increased breastmilk ovalbumin, and markers of immune tolerance in infants. These results highlight the potential for maternal diet to benefit infant oral tolerance development during lactation.
We present observations of rapid (sub-second) optical flux variability in V404 Cyg during its 2015 June outburst. Simultaneous three-band observations with the ULTRACAM fast imager on four nights ...show steep power spectra dominated by slow variations on ∼100–1000 s time-scales. Near the peak of the outburst on June 26, a dramatic change occurs and additional, persistent sub-second optical flaring appears close in time to giant radio and X-ray flaring. The flares reach peak optical luminosities of ∼ few × 1036 erg s−1. Some are unresolved down to a time resolution of 24 ms. Whereas the fast flares are stronger in the red, the slow variations are bluer when brighter. The redder slopes, emitted power and characteristic time-scales of the fast flares can be explained as optically thin synchrotron emission from a compact jet arising on size scales ∼140–500 Gravitational radii (with a possible additional contribution by a thermal particle distribution). The origin of the slower variations is unclear. The optical continuum spectral slopes are strongly affected by dereddening uncertainties and contamination by strong Hα emission, but the variations of these slopes follow relatively stable loci as a function of flux. Cross-correlating the slow variations between the different bands shows asymmetries on all nights consistent with a small red skew (i.e. red lag). X-ray reprocessing and non-thermal emission could both contribute to these. These data reveal a complex mix of components over five decades in time-scale during the outburst.
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