56 research outputs found

    Wavefront correction with a ferrofluid deformable mirror: experimental results and recent developments

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    We present the research status of a deformable mirror made of a magnetic liquid whose surface is actuated by a triangular array of small current carrying coils. We demonstrate that the mirror can correct a 11 microns low order aberrated wavefront to a residual RMS wavefront error 0.05 microns. Recent developments show that these deformable mirrors can reach a frequency response of several hundred hertz. A new method for linearizing the response of these mirrors is also presented.Comment: To appear in "Ground-based and Airborne Instrumentation for Astronomy II" SPIE conference, Marseille, 23-28 June 200

    The association of HLA-G polymorphism with oral and genital HPV infection in men

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    The host genetic factors that influence the natural history of human papillomavirus (HPV) infection in men are not well known. Our aim was to evaluate the role of human leukocyte antigen (HLA)-G polymorphism in oral and genital HPV infection in men. Altogether, 130 men from the Finnish Family HPV Study, with a 6-year follow-up, were included in the analyses. HLA-G alleles were tested by direct sequencing. Oral, urethral, and semen samples were collected and analyzed for 24 different HPV genotypes. Unconditional logistic regression was used to determine associations between HLA-G alleles and genotypes with HPV infection and its outcomes. Overall, eight different HLA-G alleles were identified with 15 different HLA-G genotype combinations. The most common HLA-G allele among the men was G*01:01:01 (86.2%, n = 112) followed by G*01:01:02 (36.2%, n = 47). Allele G*01:01:02 showed to be protective against any- and high-risk (HR) oral HPV (OR range of 0.20-0.24, 95% CI range of 0.06-0.85). Men having allele G*01:01:01 showed a reduced risk for incident (OR 0.30, 95% CI 0.11-0.84) and persistent (OR 0.24, 95% CI 0.08-0.69) oral infections. Allele G*01:01:03 was associated with increased risk for urethral HR-HPV infections (OR 4.94, 95% CI 1.34-18.27). Among self-reported demographic data, genotype G*01:01:01/01:01:03 was associated with an increased risk for oral warts (OR 8.00, 95% CI 1.23-51.89) and allele G*01:03:01 increased the risk of pollen and/or animal allergy (OR 13.59, 95% CI 1.57-117.25). To conclude, HLA-G polymorphism in men largely impacts the outcome of an oral HPV infection and seems to associate with self-reported allergies.Peer reviewe

    Effects of the environment on the multiplicity properties of stars in the STARFORGE simulations

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    Most observed stars are part of a multiple star system, but the formation of such systems and the role of environment and various physical processes is still poorly understood. We present a suite of radiation-magnetohydrodynamic simulations of star-forming molecular clouds from the STARFORGE project that include stellar feedback with varied initial surface density, magnetic fields, level of turbulence, metallicity, interstellar radiation field, simulation geometry and turbulent driving. In our fiducial cloud the raw simulation data reproduces the observed multiplicity fractions for Solar-type and higher mass stars, similar to previous works. However, after correcting for observational incompleteness the simulation under-predicts these values. The discrepancy is likely due to the lack of disk fragmentation, as the simulation only resolves multiples that form either through capture or core fragmentation. The raw mass distribution of companions is consistent with randomly drawing from the initial mass function for the companions of >1 M⊙>1\,\mathrm{M_\odot} stars, however, accounting for observational incompleteness produces a flatter distribution similar to observations. We show that stellar multiplicity changes as the cloud evolves and anti-correlates with stellar density. This relationship also explains most multiplicity variations between runs, i.e., variations in the initial conditions that increase stellar density (increased surface density, reduced turbulence) decrease multiplicity. While other parameters, such as metallicity, interstellar radiation, and geometry significantly affect the star formation history or the IMF, varying them produces no clear trend in stellar multiplicity properties.Comment: 20 pages, 21 figures, submitted to MNRA

    HLA-G polymorphism impacts the outcome of oral HPV infections in women

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    BackroundHuman leukocyte antigen (HLA)-G may have an important role in the natural history of human papillomavirus (HPV) infection. Our aim was to evaluate the role of HLA-G in the outcome of genital and oral HPV infections in women.MethodsAnalyses included 306 women from the Finnish Family HPV-study and were followed-up for six years. Genital and oral samples were tested for 24 different HPV types with multiplex HPV genotyping. HLA-G alleles were determined through direct DNA-sequencing. Unconditional logistic regression was used to determine the associations between HLA-G genotypes and HPV infection outcomes.ResultsTen HLA-G alleles were identified. Most common HLA-G genotypes were the wild type G*01:01:01/01:01:01 (31.3%) followed by G*01:01:01/01:01:02 (26.8%). G*01:01:01/01:01:01 genotype was associated with increased risk of oral HPV infections by any HPV type or single-type with OR=1.86 (95% CI 1.14-3.04, P=0.01) and 2.22 (95% CI 1.14-3.71, P=0.02), respectively. G*04:01+ allele and the G*01:01:01/01:04:01 genotype both protected from any and single oral HPV infections; OR=0.46 (95% CI 0.23-0.89, P=0.02) and 0.53 (95% CI 0.23-0.97, P=0.03), respectively. G*01:01:02/01:04:01 genotype increased significantly the risk of infertility and its treatments, with respective OR=5.06 (95% CI 1.22-21.02, P=0.03) and OR=9.07 (95% CI 1.22-39.50, P=0.03). Both HLA-G alleles and genotypes showed several significant associations with the outcomes of oral HPV infections, but none of them had any impact on the outcomes of genital HPV infections in these women.ConclusionsThe host HLA-G genotypes appear to impact the outcomes of oral HPV infections in women but have little if any effect on genital HPV status or infection outcomes.</div

    The BAH domain of Rsc2 is a histone H3 binding domain

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    Bromo-adjacent homology (BAH) domains are commonly found in chromatin-associated proteins and fall into two classes; Remodels the Structure of Chromatin (RSC)-like or Sir3-like. Although Sir3-like BAH domains bind nucleosomes, the binding partners of RSC-like BAH domains are currently unknown. The Rsc2 subunit of the RSC chromatin remodeling complex contains an RSC-like BAH domain and, like the Sir3-like BAH domains, we find Rsc2 BAH also interacts with nucleosomes. However, unlike Sir3-like BAH domains, we find that Rsc2 BAH can bind to recombinant purified H3 in vitro, suggesting that the mechanism of nucleosome binding is not conserved. To gain insight into the Rsc2 BAH domain, we determined its crystal structure at 2.4 Å resolution. We find that it differs substantially from Sir3-like BAH domains and lacks the motifs in these domains known to be critical for making contacts with histones. We then go on to identify a novel motif in Rsc2 BAH that is critical for efficient H3 binding in vitro and show that mutation of this motif results in defective Rsc2 function in vivo. Moreover, we find this interaction is conserved across Rsc2-related proteins. These data uncover a binding target of the Rsc2 family of BAH domains and identify a novel motif that mediates this interaction

    Stars made in outflows may populate the stellar halo of the Milky Way

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    We study stellar-halo formation using six Milky-Way-mass galaxies in FIRE-2 cosmological zoom simulations. We find that 5−40 per cent of the outer (50–300 kpc) stellar halo in each system consists of in-situ stars that were born in outflows from the main galaxy. Outflow stars originate from gas accelerated by superbubble winds, which can be compressed, cool, and form co-moving stars. The majority of these stars remain bound to the halo and fall back with orbital properties similar to the rest of the stellar halo at z = 0. In the outer halo, outflow stars are more spatially homogeneous, metal-rich, and alpha-element-enhanced than the accreted stellar halo. At the solar location, up to ∼10 per cent of our kinematically identified halo stars were born in outflows; the fraction rises to as high as ∼40 per cent for the most metal-rich local halo stars ([Fe/H] >−0.5). Such stars can be retrograde and create features similar to the recently discovered Milky Way ‘Splash’ in phase space. We conclude that the Milky Way stellar halo could contain local counterparts to stars that are observed to form in molecular outflows in distant galaxies. Searches for such a population may provide a new, near-field approach to constraining feedback and outflow physics. A stellar halo contribution from outflows is a phase-reversal of the classic halo formation scenario of Eggen, Lynden-Bell & Sandange, who suggested that halo stars formed in rapidly infalling gas clouds. Stellar outflows may be observable in direct imaging of external galaxies and could provide a source for metal-rich, extreme-velocity stars in the Milky Way

    The association of HLA-G polymorphism with oral and genital HPV infection in men

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    The host genetic factors that influence the natural history of human papillomavirus (HPV) infection in men are not well known. Our aim was to evaluate the role of human leukocyte antigen (HLA)-G polymorphism in oral and genital HPV infection in men. Altogether, 130 men from the Finnish Family HPV Study, with a 6-year follow-up, were included in the analyses. HLA-G alleles were tested by direct sequencing. Oral, urethral, and semen samples were collected and analyzed for 24 different HPV genotypes. Unconditional logistic regression was used to determine associations between HLA-G alleles and genotypes with HPV infection and its outcomes. Overall, eight different HLA-G alleles were identified with 15 different HLA-G genotype combinations. The most common HLA-G allele among the men was G*01:01:01 (86.2%, n = 112) followed by G*01:01:02 (36.2%, n = 47). Allele G*01:01:02 showed to be protective against any- and high-risk (HR) oral HPV (OR range of 0.20-0.24, 95% CI range of 0.06-0.85). Men having allele G*01:01:01 showed a reduced risk for incident (OR 0.30, 95% CI 0.11-0.84) and persistent (OR 0.24, 95% CI 0.08-0.69) oral infections. Allele G*01:01:03 was associated with increased risk for urethral HR-HPV infections (OR 4.94, 95% CI 1.34-18.27). Among self-reported demographic data, genotype G*01:01:01/01:01:03 was associated with an increased risk for oral warts (OR 8.00, 95% CI 1.23-51.89) and allele G*01:03:01 increased the risk of pollen and/or animal allergy (OR 13.59, 95% CI 1.57-117.25). To conclude, HLA-G polymorphism in men largely impacts the outcome of an oral HPV infection and seems to associate with self-reported allergies

    Wavefront correction with a ferrofluid deformable mirror: experimental results and recent developments

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    ABSTRACT We present the research status of a deformable mirror made of a magnetic liquid whose surface is actuated by a triangular array of small current carrying coils. We demonstrate that the mirror can correct a 11 Âľm low order aberrated wavefront to a residual RMS wavefront error 0.05 Âľm. Recent developments show that these deformable mirrors can reach a frequency response of several hundred hertz. A new method for linearizing the response of these mirrors is also presented

    Comparison of diagnostic methods for the detection and quantification of the four sympatric Plasmodium species in field samples from Papua New Guinea

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    Accurate diagnosis of Plasmodium infections is essential for malaria morbidity and mortality reduction in tropical areas. Despite great advantages of light microscopy (LM) for malaria diagnosis, its limited sensitivity is a critical shortfall for epidemiological studies. Robust molecular diagnostics tools are thus needed.; The present study describes the development of a duplex quantitative real time PCR (qPCR) assay, which specifically detects and quantifies the four human Plasmodium species. Performance of this method was compared to PCR-ligase detection reaction-fluorescent microsphere assay (PCR_LDR_FMA), nested PCR (nPCR) and LM, using field samples collected from 452 children one to five years of age from the Sepik area in Papua New Guinea. Agreement between diagnostic methods was calcualted using kappa statistics.; The agreement of qPCR with other molecular diagnostic methods was substantial for the detection of P. falciparum, but was moderate for the detection of P. vivax, P. malariae and P. ovale. P. falciparum and P. vivax prevalence by qPCR was 40.9% and 65.7% respectively. This compares to 43.8% and 73.2% by nPCR and 47.1% and 67.5% by PCR_LDR_FMA. P. malariae and P. ovale prevalence was 4.7% and 7.3% by qPCR, 3.3% and 3.8% by nPCR, and 7.7% and 4.4% by PCR_LDR_FMA. Prevalence by LM was lower for all four species, being 25.4% for P. falciparum, 54.9% for P. vivax, 2.4% for P. malariae and 0.0% for P. ovale. The quantification by qPCR closely correlated with microscopic quantification for P. falciparum and P. vivax samples (R2 = 0.825 and R2 = 0.505, respectively). The low prevalence of P. malariae and P. ovale did not permit a solid comparative analysis of quantification for these species.; The qPCR assay developed proved optimal for detection of all four Plasmodium species. Densities by LM were well reflected in quantification results by qPCR, whereby congruence was better for P. falciparum than for P. vivax. This likely is a consequence of the generally lower P. vivax densities. Easy performance of the qPCR assay, a less laborious workflow and reduced risk of contamination, together with reduced costs per sample through reduced reaction volume, opens the possibility to implement qPCR in endemic settings as a suitable diagnostic tool for large epidemiological studies

    The Role of Galaxies and AGN in Reionising the IGM - I: Keck Spectroscopy of 5 < z < 7 Galaxies in the QSO Field J1148+5251

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    We introduce a new method for determining the influence of galaxies and active galactic nuclei (AGN) on the physical state of the intergalactic medium (IGM) at high redshift and illustrate its potential via a first application to the field of the z=6.42z=6.42 QSO J1148+5251. By correlating the spatial positions of spectroscopically-confirmed Lyman break galaxies (LBGs) with fluctuations in the Lyman alpha forest seen in the high signal-to-noise spectrum of a background QSO, we provide a statistical measure of the typical escape fraction of Lyman continuum photons close to the end of cosmic reionisation. Here we use Keck DEIMOS spectroscopy to locate 7 colour-selected LBGs in the redshift range 5.3≲z≲6.45.3\lesssim z\lesssim 6.4 and confirm a faint z=5.701z=5.701 AGN. We then examine the spatial correlation between this sample and Lyα\alpha/Lyβ\beta transmission fluctuations in a Keck ESI spectrum of the QSO. Interpreting the statistical HI proximity effect as arising from faint galaxies clustered around the detected LBGs, we translate the observed mean Lyα\alpha transmitted flux around an average detected LBG into a constraint on the mean escape fraction ⟨fesc⟩≥0.08\langle f_{\rm esc}\rangle\geq0.08 at z≃6z\simeq6. We also report evidence of the individual transverse HI proximity effect of a z=6.177z=6.177 luminous LBG via a Lyβ\beta transmission spike and two broad Lyα\alpha transmission spikes around the z=5.701z=5.701 AGN. We discuss the possible origin of such associations which suggest that while faint galaxies are primarily driving reionisation, luminous galaxies and AGN may provide important contributions to the UV background or thermal fluctuations of the IGM at z≃6z\simeq6. Although a limited sample, our results demonstrate the potential of making progress using this method in resolving one of the most challenging aspects of the contribution of galaxies and AGN to cosmic reionisation.Comment: 21 pages, 16 figures, the version accepted in MNRA
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