First Observation of the Directed Flow of D^{0} and D^{0}[over ¯] in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

We report the first measurement of rapidity-odd directed flow (v_{1}) for D^{0} and D^{0}[over ¯] mesons at midrapidity (|y|<0.8) in Au+Au collisions at sqrt[s_{NN}]=200  GeV using the STAR detector at the Relativistic Heavy Ion Collider. In 10-80% Au+Au collisions, the slope of the v_{1} rapidity dependence (dv_{1}/dy), averaged over D^{0} and D^{0}[over ¯] mesons, is -0.080±0.017(stat)±0.016(syst) for transverse momentum p_{T} above 1.5  GeV/c. The absolute value of D^{0} meson dv_{1}/dy is about 25 times larger than that for charged kaons, with 3.4σ significance. These data give a unique insight into the initial tilt of the produced matter, and offer constraints on the geometric and transport parameters of the hot QCD medium created in relativistic heavy-ion collisions.

Polarization of Λ (Λ[over ¯]) Hyperons along the Beam Direction in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

The Λ (Λ[over ¯]) hyperon polarization along the beam direction has been measured in Au+Au collisions at sqrt[s_{NN}]=200  GeV, for the first time in heavy-ion collisions. The polarization dependence on the hyperons' emission angle relative to the elliptic flow plane exhibits a second harmonic sine modulation, indicating a quadrupole pattern of the vorticity component along the beam direction, expected due to elliptic flow. The polarization is found to increase in more peripheral collisions, and shows no strong transverse momentum (p_{T}) dependence at p_{T} greater than 1  GeV/c. The magnitude of the signal is about 5 times smaller than those predicted by hydrodynamic and multiphase transport models; the observed phase of the emission angle dependence is also opposite to these model predictions. In contrast, the kinematic vorticity calculations in the blast-wave model tuned to reproduce particle spectra, elliptic flow, and the azimuthal dependence of the Gaussian source radii measured with the Hanbury Brown-Twiss intensity interferometry technique reproduce well the modulation phase measured in the data and capture the centrality and transverse momentum dependence of the polarization signal.

Observation of Excess J/ψ Yield at Very Low Transverse Momenta in Au+Au Collisions at sqrt[s_{NN}]=200 GeV and U+U Collisions at sqrt[s_{NN}]=193 GeV

We report on the first measurements of J/ψ production at very low transverse momentum (p_{T}<0.2  GeV/c) in hadronic Au+Au collisions at sqrt[s_{NN}]=200  GeV and U+U collisions at sqrt[s_{NN}]=193  GeV. Remarkably, the inferred nuclear modification factor of J/ψ at midrapidity in Au+Au (U+U) collisions reaches about 24 (52) for p_{T}<0.05  GeV/c in the 60%-80% collision centrality class. This noteworthy enhancement cannot be explained by hadronic production accompanied by cold and hot medium effects. In addition, the dN/dt distribution of J/ψ for the very low p_{T} range is presented for the first time. The distribution is consistent with that expected from the Au nucleus and shows a hint of interference. Comparison of the measurements to theoretical calculations of coherent production shows that the excess yield can be described reasonably well and reveals a partial disruption of coherent production in semicentral collisions, perhaps due to the violent hadronic interactions. Incorporating theoretical calculations, the results strongly suggest that the dramatic enhancement of J/ψ yield observed at extremely low p_{T} originates from coherent photon-nucleus interactions. In particular, coherently produced J/ψ's in violent hadronic collisions may provide a novel probe of the quark-gluon plasma.

C-48 Attachment and SES at Newborn, Two, and Four Months Related to Communication Development at Nine and Twelve Months

Objective

Previous literature linked secure infant attachment to subsequent communication competency (Murray & Yingling, 2000). Less is known about that relationship in families of varying SES. This study explores how attachment and income at newborn, two, and four months correspond with communication development at nine and twelve months.

Methods

Longitudinal (n = 30) and cross-sectional (n = 102) reports from PediaTrac□, a parent-report web-based survey to track development (Lajiness-O’Neill, et al., 2018), were collected at newborn (NB; n = 41), two (2m; n = 38), four (4m; n = 37), nine (9m; n = 38), and twelve months (12m; n = 36). The cross-sectional sample had higher income (p = .01). Attachment was measured using PediaTrac□ and the Postpartum Bonding Questionnaire (PBQ; Brockington, Fraser & Wilson, 2006). Communication was measured using PediaTrac□.

Results

A linear regression model predicted communication development at 9m and 12m from attachment and income at NB, 2m, and 4m. PBQ attachment at 2m significantly predicted communication at 9m (b = 0.12, t = 2.28, p = .049). However, income was not significant, and neither attachment nor income at NB, 2m, or 4m predicted communication at 12m.

Conclusions

More secure attachment at two months was related to better communication outcomes at nine months regardless of SES. This finding highlights the importance of parent-infant relationships at two months of age on development, indicating further research on methods to promote secure attachment and positive parent-infant interaction in families of varying SES.

Azimuthal Harmonics in Small and Large Collision Systems at RHIC Top Energies

The first (v_{1}^{fluc}), second (v_{2}), and third (v_{3}) harmonic coefficients of the azimuthal particle distribution at midrapidity are extracted for charged hadrons and studied as a function of transverse momentum (p_{T}) and mean charged particle multiplicity density ⟨N_{ch}⟩ in U+U (sqrt[s_{NN}]=193  GeV), Au+Au, Cu+Au, Cu+Cu, d+Au, and p+Au collisions at sqrt[s_{NN}]=200  GeV with the STAR detector. For the same ⟨N_{ch}⟩, the v_{1}^{fluc} and v_{3} coefficients are observed to be independent of the collision system, while v_{2} exhibits such a scaling only when normalized by the initial-state eccentricity (ϵ_{2}). The data also show that ln(v_{2}/ϵ_{2}) scales linearly with ⟨N_{ch}⟩^{-1/3}. These measurements provide insight into initial-geometry fluctuations and the role of viscous hydrodynamic attenuation on v_{n} from small to large collision systems.

Low-p_{T} e^{+}e^{-} Pair Production in Au+Au Collisions at sqrt[s_{NN}]=200 GeV and U+U Collisions at sqrt[s_{NN}]=193 GeV at STAR

We report first measurements of e^{+}e^{-} pair production in the mass region 0.4<M_{ee}<2.6  GeV/c^{2} at low transverse momentum (p_{T}<0.15  GeV/c) in noncentral Au+Au collisions at sqrt[s_{NN}]=200  GeV and U+U collisions at sqrt[s_{NN}]=193  GeV. Significant enhancement factors, expressed as ratios of data over known hadronic contributions, are observed in the 40%-80% centrality of these collisions. The excess yields peak distinctly at low p_{T} with a width (sqrt[⟨p_{T}^{2}⟩]) between 40 and 60  MeV/c. The absolute cross section of the excess depends weakly on centrality, while those from a theoretical model calculation incorporating an in-medium broadened ρ spectral function and radiation from a quark gluon plasma or hadronic cocktail contributions increase dramatically with an increasing number of participant nucleons. Model calculations of photon-photon interactions generated by the initial projectile and target nuclei describe the observed excess yields but fail to reproduce the p_{T}^{2} distributions.

Beam Energy Dependence of Jet-Quenching Effects in Au+Au Collisions at sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV

We report measurements of the nuclear modification factor R_{CP} for charged hadrons as well as identified π^{+(-)}, K^{+(-)}, and p(p[over ¯]) for Au+Au collision energies of sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. We observe a clear high-p_{T} net suppression in central collisions at 62.4 GeV for charged hadrons which evolves smoothly to a large net enhancement at lower energies. This trend is driven by the evolution of the pion spectra but is also very similar for the kaon spectra. While the magnitude of the proton R_{CP} at high p_{T} does depend on the collision energy, neither the proton nor the antiproton R_{CP} at high p_{T} exhibit net suppression at any energy. A study of how the binary collision-scaled high-p_{T} yield evolves with centrality reveals a nonmonotonic shape that is consistent with the idea that jet quenching is increasing faster than the combined phenomena that lead to enhancement.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Beam-Energy Dependence of Directed Flow of Λ, Λ[over ¯], K^{±}, K_{s}^{0}, and ϕ in Au+Au Collisions

Rapidity-odd directed-flow measurements at midrapidity are presented for Λ, Λ[over ¯], K^{±}, K_{s}^{0}, and ϕ at sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV in Au+Au collisions recorded by the Solenoidal Tracker detector at the Relativistic Heavy Ion Collider. These measurements greatly expand the scope of data available to constrain models with differing prescriptions for the equation of state of quantum chromodynamics. Results show good sensitivity for testing a picture where flow is assumed to be imposed before hadron formation and the observed particles are assumed to form via coalescence of constituent quarks. The pattern of departure from a coalescence-inspired sum rule can be a valuable new tool for probing the collision dynamics.

Continuous flow hygroscopicity-resolved relaxed eddy accumulation (Hy-Res REA) method of measuring size-resolved sodium chloride particle fluxes

The accurate representation of aerosols in climate models requires direct ambient measurement of the size- and composition-dependent particle production fluxes. Here, we present the design, testing, and analysis of data collected through the first instrument capable of measuring hygroscopicity-based, size-resolved particle fluxes using a continuous-flow Hygroscopicity-Resolved Relaxed Eddy Accumulation (Hy-Res REA) technique. The Hy-Res REA system used in this study includes a 3D sonic anemometer, two fast-response solenoid valves, two condensation particle counters, a scanning mobility particle sizer, and a hygroscopicity tandem differential mobility analyzer. The different components of the instrument were tested inside the US Environmental Protection Agency's Aerosol Test Facility for sodium chloride and ammonium sulfate particle fluxes. The new REA system design does not require particle accumulation, and therefore avoids the diffusional wall losses associated with long residence times of particles inside the air collectors of traditional REA devices. A linear relationship was found between the sodium chloride particle fluxes measured by eddy covariance and REA techniques. The particle detection limit of the Hy-Res REA flux system is estimated to be ~3 × 10⁵ m^-2 s^-1. The estimated sodium chloride particle classification limit, for the mixture of sodium chloride and ammonium sulfate particles of comparable concentrations, is ~6 × 10⁶ m^-2 s^-1.

Dijet imbalance measurements in Au+Au and pp collisions at sqrt[s_{NN}]=200 GeV at STAR

We report the first dijet transverse momentum asymmetry measurements from Au+Au and pp collisions at RHIC. The two highest-energy back-to-back jets reconstructed from fragments with transverse momenta above 2  GeV/c display a significantly higher momentum imbalance in heavy-ion collisions than in the pp reference. When reexamined with correlated soft particles included, we observe that these dijets then exhibit a unique new feature-momentum balance is restored to that observed in pp for a jet resolution parameter of R=0.4, while rebalancing is not attained with a smaller value of R=0.2.

Measurement of D^{0} Azimuthal Anisotropy at Midrapidity in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

We report the first measurement of the elliptic anisotropy (v_{2}) of the charm meson D^{0} at midrapidity (|y|<1) in Au+Au collisions at sqrt[s_{NN}]=200  GeV. The measurement was conducted by the STAR experiment at RHIC utilizing a new high-resolution silicon tracker. The measured D^{0} v_{2} in 0%-80% centrality Au+Au collisions can be described by a viscous hydrodynamic calculation for a transverse momentum (p_{T}) of less than 4  GeV/c. The D^{0} v_{2} as a function of transverse kinetic energy (m_{T}-m_{0}, where m_{T}=sqrt[p_{T}^{2}+m_{0}^{2}]) is consistent with that of light mesons in 10%-40% centrality Au+Au collisions. These results suggest that charm quarks have achieved local thermal equilibrium with the medium created in such collisions. Several theoretical models, with the temperature-dependent, dimensionless charm spatial diffusion coefficient (2πTD_{s}) in the range of ∼2-12, are able to simultaneously reproduce our D^{0} v_{2} result and our previously published results for the D^{0} nuclear modification factor.

Abstract P5-06-04: Distinct BRCA1 and BRCA2 specific functions at stalled replication forks - Clinical implications for differences between BRCA1 and BRCA2 mutation driven cancer

This abstract was withdrawn by the authors.

Charge-Dependent Directed Flow in Cu+Au Collisions at sqrt[s_{NN}]=200 GeV

We present the first measurement of charge-dependent directed flow in Cu+Au collisions at sqrt[s_{NN}]=200  GeV. The results are presented as a function of the particle transverse momentum and pseudorapidity for different centralities. A finite difference between the directed flow of positive and negative charged particles is observed that qualitatively agrees with the expectations from the effects of the initial strong electric field between two colliding ions with different nuclear charges. The measured difference in directed flow is much smaller than that obtained from the parton-hadron-string-dynamics model, which suggests that most of the electric charges, i.e., quarks and antiquarks, have not yet been created during the lifetime of the strong electric field, which is of the order of, or less than, 1  fm/c.

Radiotherapy effect on nano-mechanical properties and chemical composition of enamel and dentine

OBJECTIVE

To understand radiotherapy-induced dental lesions characterized by enamel loss or delamination near the dentine-enamel junction (DEJ), this study evaluated enamel and dentine nano-mechanical properties and chemical composition before and after simulated oral cancer radiotherapy.

DESIGN

Sections from seven non-carious third molars were exposed to 2 Gy fractions, 5 days/week for 7 weeks for a total of 70 Gy. Nanoindentation was used to evaluate Young's modulus, while Raman microspectroscopy was used to measure protein/mineral ratios, carbonate/phosphate ratios, and phosphate peak width. All measures were completed prior to and following radiation at the same four buccal and lingual sites 500 and 30 μm from the DEJ in enamel and dentine (E-500, E-30, D-30 and D-500).

RESULTS

The elastic modulus of enamel and dentine was significantly increased (P ≤ 0.05) following radiation. Based on Raman spectroscopic analysis, there was a significant decrease in the protein to mineral ratio (2931/430 cm(-1)) following radiation at all sites tested except at D-500, while the carbonate to phosphate ratio (1070/960 cm(-1)) increased at E-30 and decreased at D-500. Finally, phosphate peak width as measured by FWHM at 960 cm(-1) significantly decreased at both D-30 and D-500 following radiation.

CONCLUSIONS

Simulated radiotherapy produced an increase in the stiffness of enamel and dentine near the DEJ. Increased stiffness is speculated to be the result of the radiation-induced decrease in the protein content, with the percent reduction much greater in the enamel sites. Such changes in mechanical properties and chemical composition could potentially contribute to DEJ biomechanical failure leading to enamel delamination that occurs post-radiotherapy. However, other analyses are required for a better understanding of radiotherapy-induced effects on tooth structure to improve preventive and restorative treatments for oral cancer patients.