The changes in chemical composition during development of the bovine nuchal ligament

Whole bovine nuchal ligaments, or portions thereof (in the case of commercially valuable animals), were obtained from 45 animals (28 fetal and 17 postnatal) ranging in age from 110 days of gestation to 10 yr. Insoluble elastin was quantitatively prepared from the fresh ligaments by extraction with hot alkali and by a combination of multiple extractions with alkaline buffer and then repeated autoclaving. When adult samples were examined, the yields of insoluble residue by these two methods were very similar, but with young fetal samples the second method gave significantly higher values, because of incomplete purification of the elastin residue. The changes in the concentration of collagen, alkali-insoluble elastin, and DNA have been examined. DNA concentration, and, thus, cell population density, fell progressively during the fetal period of development, to reach a steady value soon after birth. Collagen appeared in appreciable quantities before elastin, but its concentration was rapidly halved at about the time of birth. Insoluble elastin concentration was low until the end of the 7th fetal month, at which time it began to rise rapidly. The rate of increase in elastin concentration remained high throughout the next 10–12 wk, by which time the adult value had been reached. Quantitative studies, on the basis of the whole ligament, showed that the total cell content rises to a maximum at birth, but falls soon after to a level about half that at birth. Total collagen production and elastin deposition continue at a steady, maximal rate over the interval from 235 days of gestation to the end of the 1st postnatal month. It is concluded that the immediate postnatal period would be the most favorable phase in which to attempt the isolation of the soluble precursor elastin

Observations of free–free and anomalous microwave emission from LDN 1622 with the 100 m Green Bank Telescope

LDN 1622 has previously been identified as a possible strong source of dust-correlated anomalous microwave emission (AME). Previous observations were limited by resolution meaning that the radio emission could not be compared with current generation high-resolution infrared data from Herschel, Spitzer or Wide-field Infrared Sky Explorer. This paper presents arcminute resolution mapping observations of LDN 1622 at 4.85 and 13.7 GHz using the 100 m Robert C. Byrd Green Bank Telescope. The 4.85 GHz map reveals a corona of free–free emission enclosing LDN 1622 that traces the photodissociation region of the cloud. The brightest peaks of the 4.85 GHz map are found to be within ≈10 per cent agreement with the expected free–free predicted by Southern H-Alpha Sky Survey Atlas H α data of LDN 1622. At 13.7 GHz, the AME flux density was found to be 7.0 ± 1.4 mJy and evidence is presented for a rising spectrum between 13.7 and 31 GHz. The spinning dust model of AME is found to naturally account for the flux seen at 13.7 GHz. Correlations between the diffuse 13.7 GHz emission and the diffuse mid-infrared emission are used to further demonstrate that the emission originating from LDN 1622 at 13.7 GHz is described by the spinning dust model

First Season QUIET Observations: Measurements of Cosmic Microwave Background Polarization Power Spectra at 43 GHz in the Multipole Range 25 ≤ ℓ ≤ 475

The Q/U Imaging ExperimenT (QUIET) employs coherent receivers at 43 GHz and 94 GHz, operating on the Chajnantor plateau in the Atacama Desert in Chile, to measure the anisotropy in the polarization of the cosmic microwave background (CMB). QUIET primarily targets the B modes from primordial gravitational waves. The combination of these frequencies gives sensitivity to foreground contributions from diffuse Galactic synchrotron radiation. Between 2008 October and 2010 December, over 10,000 hr of data were collected, first with the 19 element 43 GHz array (3458 hr) and then with the 90 element 94 GHz array. Each array observes the same four fields, selected for low foregrounds, together covering ≈1000 deg^2. This paper reports initial results from the 43 GHz receiver, which has an array sensitivity to CMB fluctuations of 69 μK√s. The data were extensively studied with a large suite of null tests before the power spectra, determined with two independent pipelines, were examined. Analysis choices, including data selection, were modified until the null tests passed. Cross-correlating maps with different telescope pointings is used to eliminate a bias. This paper reports the EE, BB, and EB power spectra in the multipole range ℓ = 25-475. With the exception of the lowest multipole bin for one of the fields, where a polarized foreground, consistent with Galactic synchrotron radiation, is detected with 3σ significance, the E-mode spectrum is consistent with the ΛCDM model, confirming the only previous detection of the first acoustic peak. The B-mode spectrum is consistent with zero, leading to a measurement of the tensor-to-scalar ratio of r = 0.35^(+1.06)_(–0.87). The combination of a new time-stream "double-demodulation" technique, side-fed Dragonian optics, natural sky rotation, and frequent boresight rotation leads to the lowest level of systematic contamination in the B-mode power so far reported, below the level of r = 0.1

Cryogenic microstripline-on-Kapton microwave interconnects

Simple broadband microwave interconnects are needed for increasing the size of focal plane heterodyne radiometer arrays. We have measured loss and cross-talk for arrays of microstrip transmission lines in flex circuit technology at 297 and 77 K, finding good performance to at least 20 GHz. The dielectric constant of Kapton substrates changes very little from 297 to 77 K, and the electrical loss drops. The small cross-sectional area of metal in a printed circuit structure yields overall thermal conductivities similar to stainless steel coaxial cable. Operationally, the main performance tradeoffs are between crosstalk and thermal conductivity. We tested a patterned ground plane to reduce heat flux.Comment: 3 pages, 3 figures, submitted to The Review of Scientific Instrument

The Q/U Imaging Experiment: Polarization Measurements of Radio Sources at 43 and 95 GHz

We present polarization measurements of extragalactic radio sources observed during the cosmic microwave background polarization survey of the Q/U Imaging Experiment (QUIET), operating at 43 GHz (Q-band) and 95 GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are ~480 such sources within QUIET's four low-foreground survey patches, including the nearby radio galaxies Centaurus A and Pictor A. The median error on our polarized flux density measurements is 30–40 mJy per Stokes parameter. At signal-to-noise ratio > 3 significance, we detect linear polarization for seven sources in Q-band and six in W-band; only 1.3 ± 1.1 detections per frequency band are expected by chance. For sources without a detection of polarized emission, we find that half of the sources have polarization amplitudes below 90 mJy (Q-band) and 106 mJy (W-band), at 95% confidence. Finally, we compare our polarization measurements to intensity and polarization measurements of the same sources from the literature. For the four sources with WMAP and Planck intensity measurements >1 Jy, the polarization fractions are above 1% in both QUIET bands. At high significance, we compute polarization fractions as much as 10%–20% for some sources, but the effects of source variability may cut that level in half for contemporaneous comparisons. Our results indicate that simple models—ones that scale a fixed polarization fraction with frequency—are inadequate to model the behavior of these sources and their contributions to polarization maps

Re-imagining community participation at the district level: Lessons from the DIALHS collaboration.

In South Africa, the value of community participation as one of the central components of a primary health care approach is highlighted in legislation, policy documents and strategic plans. There is widespread acceptance that community participation strengthens community empowerment, disease prevention and access to services. Since 2010, the District Innovation and Action Learning for Health System Development collaboration has co-produced knowledge about how to strengthen district health systems. Nested within this collaboration is a series of engagements seeking to understand and strengthen community participation including a multi-stakeholder health risks and assets mapping activity; ‘Local Action Group’ initiatives; reflective meetings with service colleagues about community participation experiences; and a capacity-development initiative (community participation-related short courses and mentoring). These engagements hold a number of lessons for those interested in enhancing the population orientation of primary health care and the district health system, the first of which is the clear benefit to those interested in community roles and engagement of convening spaces for dialogue. However, it is not easy to generate and sustain these spaces. Through the application of a framework of collective capacity, this chapter aims to shed light on why this is the case, and in so doing, to highlight a second lesson, which is the perhaps unrecognised capacities of certain cadres, particularly environmental health practitioners, in the implementation of community participation. Ultimately, the chapter seeks to stimulate thinking and engagement about the ways in which dialogue and participation can enrich the South African health system

The chameleon groups of Richard J. Thompson: automorphisms and dynamics

The automorphism groups of several of Thompson's countable groups of piecewise linear homeomorphisms of the line and circle are computed and it is shown that the outer automorphism groups of these groups are relatively small. These results can be interpreted as stability results for certain structures of PL functions on the circle. Machinery is developed to relate the structures on the circle to corresponding structures on the line

GHRS and ORFEUS-II Observations of the Highly Ionized Interstellar Medium Toward ESO141-055

We present Goddard High Resolution Spectrograph and ORFEUS-II measurements of Si IV, CIV, N V, and O VI absorption in the interstellar medium of the Galactic disk and halo toward the nucleus of the Seyfert galaxy ESO141-055. The high ionization absorption is strong, with line strengths consistent with the spectral signature expected for hot (log T = 5-6) collisionally ionized gas in either a ``Galactic fountain'' or an inhomogeneous medium containing a mixture of conductive interfaces and turbulent mixing layers. The total O VI column density of log N ~ 15 suggests that the scale height of O VI is large (>3 kpc) in this direction. Comparison of the high ion column densities with measurements for other sight lines indicates that the highly ionized gas distribution is patchy. The amount of O VI perpendicular to the Galactic plane varies by at least a factor of ~4 among the complete halo sight lines thus far studied. In addition to the high ion absorption, lines of low ionization species are also present in the spectra. With the possible exception of Ar I, which may have a lower than expected abundance resulting from partial photoionization of gas along the sight line, the absorption strengths are typical of those expected for the warm, neutral interstellar medium. The sight line intercepts a cold molecular cloud with log N(H2) ~ 19. The cloud has an identifiable counterpart in IRAS 100-micron emission maps of this region of the sky. We detect a Ly-alpha absorber associated with ESO141-055 at z = 0.03492. This study presents an enticing glimpse into the interstellar and intergalactic absorption patterns that will be observed at high spectral resolution by the Far Ultraviolet Spectroscopic Explorer.Comment: 24 pages + 8 figures, uses aaspp4.sty. Accepted for publication in Ap

Role of the Fractalkine Receptor in CNS Autoimmune Inflammation: New Approach Utilizing a Mouse Model Expressing the Human CX3CR1

Multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS) is the leading cause of non-traumatic neurological disability in young adults. Immune mediated destruction of myelin and oligodendrocytes is considered the primary pathology of MS, but progressive axonal loss is the major cause of neurological disability. In an effort to understand microglia function during CNS inflammation, our laboratory focuses on the fractalkine/CX3CR1 signaling as a regulator of microglia neurotoxicity in various models of neurodegeneration. Fractalkine (FKN) is a transmembrane chemokine expressed in the CNS by neurons and signals through its unique receptor CX3CR1 present in microglia. During experimental autoimmune encephalomyelitis (EAE), CX3CR1 deficiency confers exacerbated disease defined by severe inflammation and neuronal loss. The CX3CR1 human polymorphism I249/M280 present in ∼20% of the population exhibits reduced adhesion for FKN conferring defective signaling whose role in microglia function and influence on neurons during MS remains unsolved. The aim of this study is to assess the effect of weaker signaling through hCX3CR1I249/M280 during EAE. We hypothesize that dysregulated microglial responses due to impaired CX3CR1 signaling enhance neuronal/axonal damage. We generated an animal model replacing the mouse CX3CR1 locus for the hCX3CR1I249/M280 variant. Upon EAE induction, these mice exhibited exacerbated EAE correlating with severe inflammation and neuronal loss. We also observed that mice with aberrant CX3CR1 signaling are unable to produce FKN and ciliary neurotrophic factor during EAE in contrast to wild type mice. Our results provide validation of defective function of the hCX3CR1I249/M280 variant and the foundation to broaden the understanding of microglia dysfunction during neuroinflammation. © 2018 Cardona et al