Toward Empirical Constraints on the Global Redshifted 21 cm Brightness Temperature During the Epoch of Reionization

Preliminary results are presented from a simple, single-antenna experiment designed to measure the all-sky radio spectrum between 100 and 200 MHz. The system used an internal comparison-switching scheme to reduce non-smooth instrumental contaminants in the measured spectrum to 75 mK. From the observations, we place an initial upper limit of 450 mK on the relative brightness temperature of the redshifted 21 cm contribution to the spectrum due to neutral hydrogen in the intergalactic medium (IGM) during the epoch of reionization, assuming a rapid transition to a fully ionized IGM at a redshift of 8. With refinement, this technique should be able to distinguish between slow and fast reionization scenarios. To constrain the duration of reionization to dz > 2, the systematic residuals in the measured spectrum must be reduced to 3 mK.Comment: Submitted to ApJ. 9 pages including 6 figure

Moving Toward Equal Ground: Engaging the Capacity of Youth, Families, and Communities to Improve Treatment Services and Outcomes in the Juvenile Justice System

Outlines RWJF's Reclaiming Futures project, describes successful programs at ten sites, and shares lessons learned about the importance of involving families and communities in improving the juvenile justice system's drug and alcohol treatment programs

A lower limit of dz > 0.06 for the duration of the reionization epoch

Observations of the 21-centimetre line of atomic hydrogen in the early Universe directly probe the history of the reionization of the gas between galaxies. The observations are challenging, though, because of the low expected signal strength (~10 mK), and contamination by strong (>100 K) foreground synchrotron emission in the Milky Way and extragalactic continuum sources2. If reionization happened rapidly, there should be a characteristic signature visible against the smooth foreground in an all-sky spectrum. Here we report an all-sky spectrum between 100 and 200 MHz, corresponding to the redshift range 6 < z < 13 for the 21-centimetre line. The data exclude a rapid reionization timescale of dz < 0.06 at the 95% confidence level.Comment: 8 pages, 2 figures, Published in Nature, Volume 468, Issue 7325, pp. 796-798 (2010

Past, present, and future roles of long-term experiments in the LTER Network

Author Posting. © American Institute of Biological Sciences, 2012. This article is posted here by permission of American Institute of Biological Sciences for personal use, not for redistribution. The definitive version was published in BioScience 62 (2012): 377-389, doi:10.1525/bio.2012.62.4.9.The US National Science Foundation—funded Long Term Ecological Research (LTER) Network supports a large (around 240) and diverse portfolio of long-term ecological experiments. Collectively, these long-term experiments have (a) provided unique insights into ecological patterns and processes, although such insight often became apparent only after many years of study; (b) influenced management and policy decisions; and (c) evolved into research platforms supporting studies and involving investigators who were not part of the original design. Furthermore, this suite of long-term experiments addresses, at the site level, all of the US National Research Council's Grand Challenges in Environmental Sciences. Despite these contributions, we argue that the scale and scope of global environmental change requires a more-coordinated multisite approach to long-term experiments. Ideally, such an approach would include a network of spatially extensive multifactor experiments, designed in collaboration with ecological modelers that would build on and extend the unique context provided by the LTER Network.2012-10-0

Enhanced response inhibition during intensive meditation training predicts improvements in self-reported adaptive socioemotional functioning.

We examined the impact of training-induced improvements in self-regulation, operationalized in terms of response inhibition, on longitudinal changes in self-reported adaptive socioemotional functioning. Data were collected from participants undergoing 3 months of intensive meditation training in an isolated retreat setting (Retreat 1) and a wait-list control group that later underwent identical training (Retreat 2). A 32-min response inhibition task (RIT) was designed to assess sustained self-regulatory control. Adaptive functioning (AF) was operationalized as a single latent factor underlying self-report measures of anxious and avoidant attachment, mindfulness, ego resilience, empathy, the five major personality traits (extroversion, agreeableness, conscientiousness, neuroticism, and openness to experience), diffi-culties in emotion regulation, depression, anxiety, and psychological well-being. Participants in Retreat 1 improved in RIT performance and AF over time whereas the controls did not. The control participants later also improved on both dimensions during their own retreat (Retreat 2). These improved levels of RIT performance and AF were sustained in follow-up assessments conducted approximately 5 months after the training. Longitudinal dynamic models with combined data from both retreats showed that improvement in RIT performance during training influenced the change in AF over time, which is consistent with a key claim in the Buddhist literature that enhanced capacity for self-regulation is an important precursor of changes in emotional well-being

Measurement of parity-violating spin asymmetries in W-+/- production at midrapidity in longitudinally polarized p plus p collisions

We present midrapidity measurements from the PHENIX experiment of large parity-violating single-spin asymmetries of high transverse momentum electrons and positrons from W-+/-/Z decays, produced in longitudinally polarized p + p collisions at center of mass energies of root s = 500 and 510 GeV. These asymmetries allow direct access to the antiquark polarized parton distribution functions due to the parity-violating nature of the W-boson coupling to quarks and antiquarks. The results presented are based on data collected in 2011, 2012, and 2013 with an integrated luminosity of 240 pb(-1), which exceeds previous PHENIX published results by a factor of more than 27. These high Q(2) data probe the parton structure of the proton at W mass scale and provide an important addition to our understanding of the antiquark parton helicity distribution functions at an intermediate Bjorken x value of roughly M-W / root s = 0.16

phi meson production in the forward/backward rapidity region in Cu plus Au collisions at root s(NN)=200 GeV

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured phi meson production and its nuclear modification in asymmetric Cu + Au heavy-ion collisions at root s(NN) = 200 GeV at both forward Cu-going direction (1.2 \u3c y \u3c 2.2) and backward Au-going direction (-2.2 \u3c y \u3c -1.2) rapidities. The measurements are performed via the dimuon decay channel and reported as a function of the number of participating nucleons, rapidity, and transverse momentum. In the most central events, 0%-20% centrality, the phi meson yield integrated over 1 \u3c pT \u3c 5 GeV/c prefers a smaller value, which means a larger nuclear modification, in the Cu-going direction compared to the Au-going direction. Additionally, the nuclear-modification factor in Cu + Au collisions averaged over all centrality is measured to be similar to the previous PHENIX result in d + Au collisions for these rapidities

Transverse energy production and charged-particle multiplicity at midrapidity in various systems from root s(NN)=7.7 to 200 GeV

Measurements of midrapidity charged-particle multiplicity distributions, dN(ch)/d eta, and midrapidity transverse-energy distributions, dE(T)/d eta, are presented for a variety of collision systems and energies. Included are distributions for Au + Au collisions at root s(NN) = 200, 130, 62.4, 39, 27, 19.6, 14.5, and 7.7 GeV, Cu + Cu collisions at root s(NN) = 200 and 62.4 GeV, Cu + Au collisions at root s(NN) = 200 GeV, U + U collisions at root s(NN) = 193 GeV, d + Au collisions at root s(NN) = 200 GeV, He-3 + Au collisions at root s(NN) = 200 GeV, and p + p collisions at root s(NN) = 200 GeV. Centrality-dependent distributions at midrapidity are presented in terms of the number of nucleon participants, N-part, and the number of constituent quark participants, N-qp. For all A + A collisions down to root s(NN) = 7.7 GeV, it is observed that the midrapidity data are better described by scaling with N-qp than scaling with N-part. Also presented are estimates of the Bjorken energy density, epsilon(BJ), and the ratio of dE(T)/d eta to dN(ch)/d eta, the latter of which is seen to be constant as a function of centrality for all systems

The arrival directions of the most energetic cosmic rays

In this Letter we examine the arrival directions of the most energetic cosmic rays (E > 2 * 10^19 eV) detected by several air shower experiments. We find that data taken by different air shower arrays show positive correlations, indicating a non--uniform arrival direction distribution. We also find that the events with energy $ > 4 * 10^19 eV exhibit a correlation with the general direction of the supergalactic plane, where a large number of potential sources is located. If confirmed by data from other experiments our results would support models for the extragalactic origin of the highest energy cosmic rays.Comment: 7 pages; 1 figure included; uuencoded, compressed PostScript file; final version, corrected in some points, accepted for publication in Phys.Rev.Let