Double Spin Asymmetries A_NN and A_SS at sqrt{s}=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC

We present the first measurements of the double spin asymmetries A_NN and A_SS at sqrt{s}=200 GeV, obtained by the pp2pp experiment using polarized proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were collected in the four momentum transfer t range 0.01<|t|<0.03 (GeV/c)^2. The measured asymmetries, which are consistent with zero, allow us to estimate upper limits on the double helicity-flip amplitudes phi_2 and phi_4 at small t as well as on the difference Delta(sigma_T) between the total cross sections for transversely polarized protons with antiparallel or parallel spin orientations.Comment: 13 pages with 3 figures. Final version accepted by Phys. Lett.

Distinct and stage-specific contributions of TET1 and TET2 to stepwise cytosine oxidation in the transition from naive to primed pluripotency

Cytosine DNA bases can be methylated by DNA methyltransferases and subsequently oxidized by TET proteins. The resulting 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC) are considered demethylation intermediates as well as stable epigenetic marks. To dissect the contributions of these cytosine modifying enzymes, we generated combinations of Tet knockout (KO) embryonic stem cells (ESCs) and systematically measured protein and DNA modification levels at the transition from naive to primed pluripotency. Whereas the increase of genomic 5-methylcytosine (5mC) levels during exit from pluripotency correlated with an upregulation of the de novo DNA methyltransferases DNMT3A and DNMT3B, the subsequent oxidation steps turned out to be far more complex. The strong increase of oxidized cytosine bases (5hmC, 5fC, and 5caC) was accompanied by a drop in TET2 levels, yet the analysis of KO cells suggested that TET2 is responsible for most 5fC formation. The comparison of modified cytosine and enzyme levels in Tet KO cells revealed distinct and differentiation-dependent contributions of TET1 and TET2 to 5hmC and 5fC formation arguing against a processive mechanism of 5mC oxidation. The apparent independent steps of 5hmC and 5fC formation suggest yet to be identified mechanisms regulating TET activity that may constitute another layer of epigenetic regulation

Polarised Quark Distributions in the Nucleon from Semi-Inclusive Spin Asymmetries

We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range $0.003$1 GeV$^2$. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at $Q^2$=10 GeV$^2$. The polarised $u$ valence quark distribution, $\Delta u_v(x)$, is positive and the polarisation increases with $x$. The polarised $d$ valence quark distribution, $\Delta d_v(x)$, is negative and the non-strange sea distribution, $\Delta \bar q(x)$, is consistent with zero over the measured range of $x$. We find for the first moments $\int_0^1 \Delta u_v(x) dx = 0.77 \pm 0.10 \pm 0.08$, $\int_0^1 \Delta d_v(x) dx = -0.52 \pm 0.14 \pm 0.09$ and $\int_0^1 \Delta \bar q(x) dx= 0.01 \pm 0.04 \pm 0.03$, where we assumed $\Delta \bar u(x) = \Delta \bar d(x)$. We also determine for the first time the second moments of the valence distributions $\int_0^1 x \Delta q_v(x) dx$.Comment: 17 page

Precision Measurement of the Longitudinal Double-spin Asymmetry for Inclusive Jet Production in Polarized Proton Collisions at s=200\sqrt{s}=200 GeV

We report a new high-precision measurement of the mid-rapidity inclusive jet longitudinal double-spin asymmetry, $A_{LL}$, in polarized $pp$ collisions at center-of-mass energy $\sqrt{s}=200$ GeV. The STAR data place stringent constraints on polarized parton distribution functions extracted at next-to-leading order from global analyses of inclusive deep inelastic scattering (DIS), semi-inclusive DIS, and RHIC $pp$ data. The measured asymmetries provide evidence for positive gluon polarization in the Bjorken-$x$ region $x>0.05$.Comment: 7 pages, 3 figure

Measurements of ep -\u3e e\u27 pi(+) pi(-) p\u27 cross sections with CLAS at 1.40 GeV \u3c W \u3c 2.0 GeV and 2.0GeV(2) \u3c Q(2) \u3c 5.0 GeV2

This paper reports new exclusive cross sections for ep -\u3e e\u27 pi(+) pi(-) p\u27 using the CLAS detector at Jefferson Laboratory. These results are presented for the first time at photon virtualities 2.0 GeV2 \u3c Q(2) \u3c 5.0 GeV2 in the center-of-mass energy range 1.4 GeV \u3c W \u3c 2.0 GeV, which covers a large part of the nucleon resonance region. Using a model developed for the phenomenological analysis of electroproduction data, we see strong indications that the relative contributions from the resonant cross sections at W \u3c 1.74 GeV increase with Q(2). These data considerably extend the kinematic reach of previous measurements. Exclusive ep -\u3e e\u27 pi(+) pi(-) p\u27 cross section measurements are of particular importance for the extraction of resonance electrocouplings in the mass range above 1.6 GeV

Exclusive ρ0\rho^0 electroproduction on the proton at CLAS

The $e p\to e^\prime p \rho^0$ reaction has been measured, using the 5.754 GeV electron beam of Jefferson Lab and the CLAS detector. This represents the largest ever set of data for this reaction in the valence region. Integrated and differential cross sections are presented. The $W$, $Q^2$ and $t$ dependences of the cross section are compared to theoretical calculations based on $t$-channel meson-exchange Regge theory on the one hand and on quark handbag diagrams related to Generalized Parton Distributions (GPDs) on the other hand. The Regge approach can describe at the $\approx$ 30% level most of the features of the present data while the two GPD calculations that are presented in this article which succesfully reproduce the high energy data strongly underestimate the present data. The question is then raised whether this discrepancy originates from an incomplete or inexact way of modelling the GPDs or the associated hard scattering amplitude or whether the GPD formalism is simply inapplicable in this region due to higher-twists contributions, incalculable at present.Comment: 29 pages, 29 figure

Prevention of recurrent sickness absence among employees with common mental disorders: design of a cluster-randomised controlled trial with cost-benefit and effectiveness evaluation

BACKGROUND: Common mental disorders, such as depression, anxiety disorder, and adjustment disorder, have emerged as a major public and occupational health problem in many countries. These disorders can have severe consequences such as absenteeism and work disability. Different interventions have been developed to improve the return-to-work of employees with common mental disorders, but still a large proportion of employees experiences health and work problems after their return-to-work. For this reason, the SHARP-at work intervention is developed to prevent a relapse of sickness absence among employees who have returned to work after a period of sickness absence because of common mental disorders. We aim to evaluate the effectiveness, cost-benefit and process of the intervention compared to care as usual. METHODS/DESIGN: The study is designed as a cluster-randomised controlled trial with randomisation at the level of the occupational physician. Employees who have returned to work after a period of sickness absence because of a common mental disorder are included in the study. Employees in the intervention group will receive the SHARP-at work intervention. The intervention focusses on active guidance of employees by occupational physicians during the first weeks of work after sickness absence. Employees in the control group will receive care as usual. Outcomes will be assessed at baseline and at 3, 6, and 12 months follow-up. The primary outcome is cumulative recurrent sickness absence days. Secondary outcome measures are mental health, work functioning, and coping. Adherence to the protocol, communication between stakeholders, and satisfaction with the treatment are the process measures assessed in both study groups. Cost-benefit is calculated from a societal perspective. Finally, prognostic factors for a relapse of sickness absence are investigated. DISCUSSION: This study goes beyond return-to-work by focussing on the prevention of recurrent sickness absence. The study incorporates not only outcomes on sickness absence and mental health but also on health-related work functioning. The results of this study can contribute to a further development of practice guidelines and the promotion of sustainable work participation. TRIAL REGISTRATION: NTR1963

eta-prime photoproduction on the proton for photon energies from 1.527 to 2.227 GeV

Differential cross sections for the reaction gamma p -> eta-prime p have been measured with the CLAS spectrometer and a tagged photon beam with energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data indicate for the first time the coupling of the etaprime N channel to both the S_11(1535) and P_11(1710) resonances, known to couple strongly to the eta N channel in photoproduction on the proton, and the importance of j=3/2 resonances in the process.Comment: 6 pages, 3 figure