93 research outputs found

    Evolution of dopant-induced helium nanoplasmas

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    Two-component nanoplasmas generated by strong-field ionization of doped helium nanodroplets are studied in a pump-probe experiment using few-cycle laser pulses in combination with molecular dynamics simulations. High yields of helium ions and a pronounced, droplet size-dependent resonance structure in the pump-probe transients reveal the evolution of the dopant-induced helium nanoplasma. The pump-probe dynamics is interpreted in terms of strong inner ionization by the pump pulse and resonant heating by the probe pulse which controls the final charge states detected via the frustration of electron-ion recombination

    First Results from the HerschelHerschel and ALMA Spectroscopic Surveys of the SMC: The Relationship Between [CII]-bright Gas and CO-bright Gas at Low Metallicity

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    The Small Magellanic Cloud (SMC) provides the only laboratory to study the structure of molecular gas at high resolution and low metallicity. We present results from the Herschel Spectroscopic Survey of the SMC (HS3^{3}), which mapped the key far-IR cooling lines [CII], [OI], [NII], and [OIII] in five star-forming regions, and new ALMA 7m-array maps of 12^{12}CO and 13^{13}CO (2−1)(2-1) with coverage overlapping four of the five HS3^{3} regions. We detect [CII] and [OI] throughout all of the regions mapped. The data allow us to compare the structure of the molecular clouds and surrounding photodissociation regions using 13^{13}CO, CO, [CII], and [OI] emission at <10<10" (<3<3 pc) scales. We estimate Av using far-IR thermal continuum emission from dust and find the CO/[CII] ratios reach the Milky Way value at high AV_{V} in the centers of the clouds and fall to ∌1/5−1/10×\sim{1/5-1/10}\times the Milky Way value in the outskirts, indicating the presence of translucent molecular gas not traced by bright CO emission. We estimate the amount of molecular gas traced by bright [CII] emission at low AV_{V} and bright CO emission at high AV_{V}. We find that most of the molecular gas is at low AV_{V} and traced by bright [CII] emission, but that faint CO emission appears to extend to where we estimate the H2_{2}-to-HI transition occurs. By converting our H2_{2} gas estimates to a CO-to-H2_{2} conversion factor (XCOX_{CO}), we show that XCOX_{CO} is primarily a function of AV_{V}, consistent with simulations and models of low metallicity molecular clouds.Comment: Accepted for publication in Ap

    Does Father Know Best? A Formal Model of the Paternal Influence on Childhood Social Anxiety

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    We explore paternal social anxiety as a specific risk factor for childhood social anxiety in a rational optimization model. In the course of human evolution, fathers specialized in external protection (e.g., confronting the external world) while mothers specialized in internal protection (e.g., providing comfort and food). Thus, children may instinctively be more influenced by the information signaled by paternal versus maternal behavior with respect to potential external threats. As a result, if fathers exhibit social anxiety, children interpret it as a strong negative signal about the external social world and rationally adjust their beliefs, thus becoming stressed. Under the assumption that paternal signals on social threats are more influential, a rational cognitive inference leads children of socially anxious fathers to develop social anxiety, unlike children of socially anxious mothers. We show in the model that mothers cannot easily compensate for anxious paternal behavior, but choose to increase maternal care to maintain the child’s wellbeing. We discuss research directions to test the proposed model as well as implications for the prevention and treatment of child social anxiety

    Updated 34-band Photometry for the SINGS/KINGFISH Samples of Nearby Galaxies

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    The American Astronomical Society. All rights reserved..We present an update to the ultraviolet-to-radio database of global broadband photometry for the 79 nearby galaxies that comprise the union of the KINGFISH (Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel\textit{Herschel}) and SINGS (Spitzer \textit{Spitzer } Infrared Nearby Galaxies Survey) samples. The 34-band data set presented here includes contributions from observational work carried out with a variety of facilities including GALEX\textit{GALEX}, SDSS, Pan-STARRS1, NOAO, 2MASS, \textit{NOAO, 2MASS, } Wide-Field Infrared Survey Explorer, Spitzer, Herschel, Planck, JCMT\textit{Wide-Field Infrared Survey Explorer, Spitzer, Herschel, Planck, JCMT}, and the VLA\textit{VLA}. Improvements of note include recalibrations of previously published SINGS BVR C_{C} I C_{C} and KINGFISH far-infrared/submillimeter photometry. Similar to previous results in the literature, an excess of submillimeter emission above model predictions is seen primarily for low-metallicity dwarf or irregular galaxies. This 33-band photometric data set for the combined KINGFISH+SINGS sample serves as an important multiwavelength reference for the variety of galaxies observed at low redshift. A thorough analysis of the observed spectral energy distributions is carried out in a companion paper

    Gender balance in ECEC : why is there s little progres?

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    Social attitudes about male participation in the upbringing of children have changed considerably over the past few decades. Men are now seen as important for children’s development and learning. Research from many countries worldwide shows that in early childhood care and education (ECEC), male workers are welcomed by female colleagues and parents. In the last two decades there have been initiatives for more men in ECEC in several European countries. Nevertheless the proportion of male workers ECEC remains low worldwide. This article questions the persisting gender imbalance in ECEC and analyzes ambivalences regarding more men in the field. Based on recent gender theory, efforts and limits of strategies for more male students and workers in ECEC in Belgium, Norway and Germany are discussed. It is concluded that deeply held gendered attitudes and practices in the field of care and educational work with young children have to be put into question. More space in ECEC for embodied subjectivities is needed to overcome essentialist conceptions of differences between body and mind, women and men

    Updated 34-band Photometry for the SINGS/KINGFISH Samples of Nearby Galaxies

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    The American Astronomical Society. All rights reserved..We present an update to the ultraviolet-to-radio database of global broadband photometry for the 79 nearby galaxies that comprise the union of the KINGFISH (Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel\textit{Herschel}) and SINGS (Spitzer \textit{Spitzer } Infrared Nearby Galaxies Survey) samples. The 34-band data set presented here includes contributions from observational work carried out with a variety of facilities including GALEX\textit{GALEX}, SDSS, Pan-STARRS1, NOAO, 2MASS, \textit{NOAO, 2MASS, } Wide-Field Infrared Survey Explorer, Spitzer, Herschel, Planck, JCMT\textit{Wide-Field Infrared Survey Explorer, Spitzer, Herschel, Planck, JCMT}, and the VLA\textit{VLA}. Improvements of note include recalibrations of previously published SINGS BVR C_{C} I C_{C} and KINGFISH far-infrared/submillimeter photometry. Similar to previous results in the literature, an excess of submillimeter emission above model predictions is seen primarily for low-metallicity dwarf or irregular galaxies. This 33-band photometric data set for the combined KINGFISH+SINGS sample serves as an important multiwavelength reference for the variety of galaxies observed at low redshift. A thorough analysis of the observed spectral energy distributions is carried out in a companion paper

    Understanding Communication Signals during Mycobacterial Latency through Predicted Genome-Wide Protein Interactions and Boolean Modeling

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    About 90% of the people infected with Mycobacterium tuberculosis carry latent bacteria that are believed to get activated upon immune suppression. One of the fundamental challenges in the control of tuberculosis is therefore to understand molecular mechanisms involved in the onset of latency and/or reactivation. We have attempted to address this problem at the systems level by a combination of predicted functional protein∶protein interactions, integration of functional interactions with large scale gene expression studies, predicted transcription regulatory network and finally simulations with a Boolean model of the network. Initially a prediction for genome-wide protein functional linkages was obtained based on genome-context methods using a Support Vector Machine. This set of protein functional linkages along with gene expression data of the available models of latency was employed to identify proteins involved in mediating switch signals during dormancy. We show that genes that are up and down regulated during dormancy are not only coordinately regulated under dormancy-like conditions but also under a variety of other experimental conditions. Their synchronized regulation indicates that they form a tightly regulated gene cluster and might form a latency-regulon. Conservation of these genes across bacterial species suggests a unique evolutionary history that might be associated with M. tuberculosis dormancy. Finally, simulations with a Boolean model based on the regulatory network with logical relationships derived from gene expression data reveals a bistable switch suggesting alternating latent and actively growing states. Our analysis based on the interaction network therefore reveals a potential model of M. tuberculosis latency
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