Since induction of the AgrAbility program through appropriations contained in the 1990 Farm Bill, the national and state/regional AgrAbility projects have used a variety of methods to disseminate ...information about assistive technology (AT) to farmers, ranchers, and other agricultural workers with disabilities. To date, no known research has been conducted to assess those delivery methods from the perspectives of either the persons with disabilities in need of information or the education and rehabilitation professionals who work with them. This study's purpose was two-fold: (1) review various dissemination strategies to identify those documented as being more effective, and (2) conduct surveys to ascertain the perspectives of AgrAbility project professionals and a national network of farmers and ranchers with disabilities (called the Barn Builders). Key findings of the study were as follows: (1) the farmers and ranchers most preferred receiving information via printed newsletters (71%) and printed publications (67%); (2) AgrAbility staff most preferred receiving information via internet-based publication access (61%), e-mail (60%), and printed publications (58%); (3) many farmers and ranchers perceived that dissemination strategies were moving toward the internet (53%) and that AT information was generally more available now than in the past (38%); (4) both AgrAbility staff and the Barn Builders tended to agree that farmers still wanted to receive information in printed form; and (5) neither age nor education level appeared to be a strong predictor of internet use by farmers. Key recommendations to enhance the effectiveness of current AT information delivery methods included: (1) implementing effective document management strategies for all information resources, especially for online content; and (2) minimizing language translation efforts, since such a small percentage of the AgrAbility project customer base is primarily non-English speaking. It is believed that the findings of this study also have implications for service delivery strategies in other areas, including topics relating to agricultural safety and health.
We report the triton (t) production in midrapidity (|y|<0.5) Au+Au collisions at sqrts_{NN}=7.7-200 GeV measured by the STAR experiment from the first phase of the beam energy scan at the ...Relativistic Heavy Ion Collider. The nuclear compound yield ratio (N_{t}×N_{p}/N_{d}^{2}), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity (dN_{ch}/dη) and follows a scaling behavior. The dN_{ch}/dη dependence of the yield ratio is compared to calculations from coalescence and thermal models. Enhancements in the yield ratios relative to the coalescence baseline are observed in the 0%-10% most central collisions at 19.6 and 27 GeV, with a significance of 2.3σ and 3.4σ, respectively, giving a combined significance of 4.1σ. The enhancements are not observed in peripheral collisions or model calculations without critical fluctuation, and decreases with a smaller p_{T} acceptance. The physics implications of these results on the QCD phase structure and the production mechanism of light nuclei in heavy-ion collisions are discussed.
We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C_{5}, C_{6}) and factorial cumulants (κ_{5}, κ_{6}) of net-proton and proton number distributions, ...from center-of-mass energy (sqrts_{NN}) 3 GeV to 200 GeV Au+Au collisions at RHIC. Cumulant ratios of net-proton (taken as proxy for net-baryon) distributions generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at 3 GeV. The measured values of C_{6}/C_{2} for 0%-40% centrality collisions show progressively negative trend with decreasing energy, while it is positive for the lowest energy studied. These observed negative signs are consistent with QCD calculations (for baryon chemical potential, μ_{B}≤110 MeV) which contains the crossover transition range. In addition, for energies above 7.7 GeV, the measured proton κ_{n}, within uncertainties, does not support the two-component (Poisson+binomial) shape of proton number distributions that would be expected from a first-order phase transition. Taken in combination, the hyperorder proton number fluctuations suggest that the structure of QCD matter at high baryon density, μ_{B}∼750 MeV at sqrts_{NN}=3 GeV is starkly different from those at vanishing μ_{B}∼24 MeV at sqrts_{NN}=200 GeV and higher collision energies.
The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-π0s produced at forward pseudorapidities (2.6<η<4.0) in p+p, p+Al, and p+Au collisions at a center-of-mass ...energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back π0 pairs in p+Al and p+Au collisions compared to the p+p data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. Furthermore, the larger suppression found in p+Au relative to p+Al collisions exhibits a dependence of the saturation scale $Q^{2}_{s}$ on the mass number A . A linear scaling of the suppression with A1/3 is observed with a slope of -0.09±0.01.
Partons traversing the strongly interacting medium produced in heavy-ion collisions are expected to lose energy depending on their color charge and mass. We measure the nuclear modification factors ...for charm- and bottom-decay electrons, defined as the ratio of yields, divided by the number of binary nucleon–nucleon collisions, in
s
NN
=
200
GeV Au+Au collisions to
p
+
p
collisions (
R
AA
), or in central to peripheral Au+Au collisions (
R
CP
). We find the bottom-decay electron
R
AA
and
R
CP
to be significantly higher than those of charm-decay electrons. Model calculations including mass-dependent parton energy loss in a strongly coupled medium are consistent with the measured data. These observations provide evidence of mass ordering of charm and bottom quark energy loss when traversing through the strongly coupled medium created in heavy-ion collisions.
Elliptic flow measurements from two-, four-, and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at sqrts_{NN}=193 GeV, Cu+Au at sqrts_{NN}=200 GeV and ...Au+Au spanning the range sqrts_{NN}=11.5-200 GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and trento model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.
We report cumulants of the proton multiplicity distribution from dedicated fixed-target Au+Au collisions at sqrts_{NN}=3.0 GeV, measured by the STAR experiment in the kinematic acceptance of ...rapidity (y) and transverse momentum (p_{T}) within -0.5<y<0 and 0.4<p_{T}<2.0 GeV/c. In the most central 0%-5% collisions, a proton cumulant ratio is measured to be C_{4}/C_{2}=-0.85±0.09 (stat)±0.82 (syst), which is 2σ below the Poisson baseline with respect to both the statistical and systematic uncertainties. The hadronic transport UrQMD model reproduces our C_{4}/C_{2} in the measured acceptance. Compared to higher energy results and the transport model calculations, the suppression in C_{4}/C_{2} is consistent with fluctuations driven by baryon number conservation and indicates an energy regime dominated by hadronic interactions. These data imply that the QCD critical region, if created in heavy-ion collisions, could only exist at energies higher than 3 GeV.
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