93 research outputs found

    Managing Intra-Party Democracy: Comparing the French Socialist and British Labour Party Conferences

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    The French Socialists and British Labour consider intra-party democracy as a central tenet of their philosophies. It is a core value that orientates their political attitudes and defines their identity. Traditionally, they have privileged a particular type of decision-making, based on the sovereignty of the party conference. However, at the beginning of the 1990s, these meetings projected a damaging image of division and chaos. Confronted with the intense scrutiny of their internal debates by the media, the two parties had to find a better balance between their culture and practices, and the need to promote an image of unity and efficiency. They introduced a number of reforms that, they claim, have expanded the possibilities for individual members to participate while at the same time giving the two leaderships a firmer grip on decision-making. Based on qualitative research conducted over many years, this paper explores the parties' new attitudes to internal democracy and analyses the process of power redistribution within the organizations

    The HeI 584 A Forest as a Diagnostic of Helium Reionization

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    We discuss the potential of using the HeI 584 A forest to detect and study HeII reionization. Significant 584 A absorption is expected from intergalactic HeII regions, whereas there should be no detectable absorption from low density gas in HeIII regions. Unlike HeII Ly-alpha absorption (the subject of much recent study), the difficulty with using this transition to study HeII reionization is not saturation but rather that the absorption is weak. The Gunn-Peterson optical depth for this transition is tau ~ 0.1 x_{HeII} Delta^2 [(1+z)/5]^{9/2}, where x_{HeII} is the fraction of helium in HeII and Delta is the density in units of the cosmic mean. In addition, HeI 584 A absorption is contaminated by lower redshift HI Ly-alpha absorption with a comparable flux decrement. We estimate the requirements for a definitive detection of redshifted HeI absorption from low density gas (Delta ~ 1), which would indicate that HeII reionization was occurring. We find that this objective can be accomplished (using coeval HI Ly-alpha absorption to mask dense regions and in cross correlation) with a spectral resolution of 10^4 and a signal-to-noise ratio per resolution element of ~ 10. Such specifications may be achievable on a few known z ~ 3.5 quasar sightlines with the Cosmic Origins Spectrograph on the Hubble Space Telescope. We also discuss how HeI absorption can be used to measure the hardness of the ionizing background above 13.6 eV.Comment: 12 pages, 5 figures, updated to match published versio

    Spectral Energy Distribution Fitting: Application to Lyman Alpha-Emitting Galaxies

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    Spectral Energy Distribution (SED) fitting is a well-developed astrophysical tool that has recently been applied to high-redshift Lyman Alpha-emitting galaxies. If rest-frame ultraviolet through near-infrared photometry is available, it allows the simultaneous determination of the star formation history and dust extinction of a galaxy. Lyman Alpha-emitter SED fitting results from the literature find star formation rates ~3 M_sun/yr, stellar masses ~10^9 M_sun for the general population but ~10^10 M_sun for the subset detected by IRAC, and very low dust extinction, A_V < 0.3, although a couple of outlying analyses prefer significantly more dust and higher intrinsic star formation rates. A checklist of 14 critical choices that must be made when performing SED fitting is discussed.Comment: A review and discussion from the "Understanding Lyman-alpha Emitters" meeting in Heidelberg, Oct. 2008, 10 pages, to be published in New Astronomy Reviews. Full conference summary available as arXiv:0904.3335. Conference home-page, with presentations, is http://www.mpia.de/Public/Aktuelles/Tagungen/lae08/lae08.htm

    The galaxy–halo size relation of low-mass galaxies in FIRE

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    Galaxy sizes correlate closely with the sizes of their parent dark matter haloes, suggesting a link between halo formation and galaxy growth. However, the precise nature of this relation and its scatter remains to be understood fully, especially for low-mass galaxies. We analyse the galaxy–halo size relation (GHSR) for low-mass (⁠M⋆∼107−9M⊙⁠) central galaxies over the past 12.5 billion years with the help of cosmological volume simulations (FIREbox) from the Feedback in Realistic Environments (FIRE) project. We find a nearly linear relationship between the half-stellar mass galaxy size R1/2 and the parent dark matter halo virial radius Rvir. This relation evolves only weakly since redshift z = 5: R1/2[kpc]=(0.053±0.002)(Rvir/35kpc)0.934±0.054⁠, with a nearly constant scatter ⟨σ⟩=0.084[dex]⁠. While this ratio is similar to what is expected from models where galaxy disc sizes are set by halo angular momentum, the low-mass galaxies in our sample are not angular momentum supported, with stellar rotational to circular velocity ratios vrot/vcirc ∼ 0.15. Introducing redshift as another parameter to the GHSR does not decrease the scatter. Furthermore, this scatter does not correlate with any of the halo properties we investigate – including spin and concentration – suggesting that baryonic processes and feedback physics are instead critical in setting the scatter in the GHSR. Given the relatively small scatter and the weak dependence of the GHSR on redshift and halo properties for these low-mass central galaxies, we propose using galaxy sizes as an independent method from stellar masses to infer halo masses

    The EcoChip : a wireless multi-sensor platform for comprehensive environmental monitoring

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    This paper presents the EcoChip, a new system based on state-of-the-art electro-chemical impedance (EIS) technologies allowing the growth of single strain organisms isolated from northern habitats. This portable system is a complete and autonomous wireless platform designed to monitor and cultivate microorganisms directly sampled from their natural environment, particularly from harsh northern environments. Using 96-well plates, the EcoChip can be used in the field for realtime monitoring of bacterial growth. Manufactured with highquality electronic components, this new EIS monitoring system is designed to function at a low excitation voltage signal to avoid damaging the cultured cells. The high-precision calibration network leads to high-precision results, even in the most limiting contexts. Luminosity, humidity and temperature can also be monitored with the addition of appropriate sensors. Access to robust data storage systems and power supplies is an obvious limitation for northern research. That is why the EcoChip is equipped with a flash memory that can store data over long periods of time. To resolve the power issue, a low-power microcontroller and a power management unit control and supply all electronic building blocks. Data stored in the EcoChip’s flash memory can be transmitted through a transceiver whenever a receiver is located within the functional transmission range. In this paper, we present the measured performance of the system, along with results from laboratory tests in-vitro and from two field tests. The EcoChip has been utilized to collect bio-environemental data in the field from the northern soils and ecosystems of Kuujjuarapik and Puvirnituq, during two expeditions, in 2017 and 2018, respectively. We show that the EcoChip can effectively carry out EIS analyses over an excitation frequency ranging from 750 Hz to 10 kHz with an accuracy of 2.35%. The overall power consumption of the system was 140.4 mW in normal operating mode and 81 µW in sleep mode. The proper development of the isolated bacteria was confirmed through DNA sequencing, indicating that bacteria thrive in the EcoChip’s culture wells while the growing conditions are successfully gathered and stored

    The impact of helium reionization on the structure of the intergalactic medium

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    We examine the impact of helium reionization on the structure of the intergalactic medium (IGM). We model the reionization using a radiative transfer (RT) code coupled to the combined gravity hydrodynamics code Enzo. Neutral hydrogen and helium are initially ionized by a starburst spectrum, which is allowed to gradually evolve into a power law spectrum over the redshift interval 3 < z < 4. The temperature-density relation of the gas is found to fan out and flatten following HeII reionization, with an inversion for overdensities above 5. Peculiar velocities of up to 10 km/s are induced by the increased pressure, with the gas density field distorted over large coherent regions by 10-20%, and the dark matter by levels of 1%. The photoionization-induced flows may thus distort the matter power spectrum at comoving wavenumbers k > 0.5 h/Mpc by a few percent by z = 2. Absorption spectra for HI and HeII are drawn from the simulations, and absorption lines are fit to the spectra. A median Doppler parameter of 35 km/s is obtained for the HI absorption systems at z = 3. Dividing into subsamples optically thick and optically thin at line centre reveals that the optically thick systems undergo only mild evolution while the optically thin systems evolve rapidly following HeII reionization. A comparison between HeII and HI absorption features shows a broad distribution in the HeII and HI column density ratio, peaking near the measured value and only slightly narrower than measured. A comparison with approximate simulation methods shows moderately good agreement in the absorption line properties, but not to the precision to which they may be measured.Comment: 19 pages, 25 figures. Submitted to MNRA

    Helium reionization and the thermal proximity effect

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    We examine the temperature structure of the intergalactic medium IGM) surounding a hard radiation source, such as a Quasi-Stellar Object (QSO), as it responds to the onset of helium reionization by the source. We model the reionization using a radiative transfer (RT) code coupled to a particle-mesh (PM) N-body code. Neutral hydrogen and helium are initially ionized by a starburst spectrum, which is allowed to gradually evolve into a power law spectrum (fnu ~ nu^(-0.5)). Multiple simulations were performed with different times for the onset and dominance of the hard spectrum, with onset redshifts ranging from z = 3.5 to 5.5. The source is placed in a high-density region to mimic the expected local environment of a QSO. Simulations with the source placed in a low-density environment were also performed as control cases to explore the role of the environment on the properties of the surrounding IGM. We find in both cases that the IGM temperature within the HeIII region produced exceeds the IGM temperature before full helium reionization, resulting in a "thermal proximity effect", but that the temperature in the HeIII region increases systematically with distance from the source. With time the temperature relaxes with a reduced spread as a function of impact parameter along neighbouring lines of sight, although the trend continues to persist until z = 2. Such a trend could be detected using the widths of intervening metal absorption systems using high resolution, high signal-to-noise ratio spectra.Comment: 17 pages, 12 figures, for publication in MNRA

    The Grizzly, September 19, 1990

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    Election 1990: Hafer Speaks • Bon Voyage, Richter! • Meistersingers in England • Ursinus to Recycle? • Persian Gulf Dialog • Convocation 1990 • Ursinus Receives Japanese Grant • Slightly Steamed • The Phantoms of Ursinus • Ursinus Students Study in France • Red and Gold Hosts and Hostesses Needed • Berman Catalog Awarded • Urban Art • Bears Hound Hoyas in Opener • Field Hockey on the Ball • Bruins Club to Hold Fifth Bear Pack Run • Lady Bears Start Fast • Netters Improving • Score!! • Encourage Diversity • On Censoring Art • Not Oil Only • Prediction: War With Iraq • Going with the Flow • Bolt to Latest Discoverieshttps://digitalcommons.ursinus.edu/grizzlynews/1257/thumbnail.jp

    Front Microbiol

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    Since 2021, 3 variants of concern (VOC) have spread to France, causing successive epidemic waves. To describe the features of Alpha, Delta and Omicron VOC circulation in the Nouvelle-Aquitaine region, France, between February 2021 and February 2022. Data from the three university hospitals (UH) of Nouvelle-Aquitaine were used to describe regional SARS-CoV-2 circulation (RT-PCR positive rates and identified VOC) as well as its consequences (total number of hospitalizations and admissions in intensive care unit). They were analyzed according to the predominant variant and compared with national data. A total of 611,106 SARS-CoV-2 RT-PCR tests were performed in the 3 Nouvelle-Aquitaine UH during the study period. The 37,750 positive samples were analyzed by variant-specific RT-PCR or whole-genome sequencing. In 2021, Alpha VOC was detected from week 5 until week 35. Delta became the most prevalent variant (77.3%) in week 26, reaching 100% in week 35. It was replaced by Omicron, which was initially detected week 48, represented 77% of positive samples in week 52 and was still predominant in February 2022. The RT-PCR positive rates were 4.3, 4.2, and 21.9% during the Alpha, Delta and Omicron waves, respectively. The ratio between intensive care unit admissions and total hospitalizations was lower during the Omicron wave than during the two previous waves due to the Alpha and Delta variants. This study highlighted the need for strong regional cooperation to achieve effective SARS-CoV-2 epidemiological surveillance, in close association with the public health authorities

    Efficacy of artesunate-amodiaquine and artemether-lumefantrine fixed-dose combinations for the treatment of uncomplicated Plasmodium falciparum malaria among children aged six to 59 months in Nimba County, Liberia: an open-label randomized non-inferiority trial.

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    Prospective efficacy monitoring of anti-malarial treatments is imperative for timely detection of resistance development. The in vivo efficacy of artesunate-amodiaquine (ASAQ) fixed-dose combination (FDC) was compared to that of artemether-lumefantrine (AL) among children aged six to 59 months in Nimba County, Liberia, where Plasmodium falciparum malaria is endemic and efficacy data are scarce
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