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The vascular endothelial growth factor (VEGF) family of genes has been implicated in the clinical development of Alzheimer’s Disease (AD). A previous study identified associations between gene expression of VEGF family members in the prefrontal cortex and cognitive performance and AD pathology. This study explored if those associations were also observed in the blood. Consistent with previous observations in brain tissue, higher blood gene expression of placental growth factor (PGF) was associated with a faster rate of memory decline (p=0.04). Higher protein abundance of FMS-related receptor tyrosine kinase 4 (FLT4) in blood was associated with biomarker levels indicative of lower amyloid and tau pathology, opposite the direction observed in brain. Also, higher gene expression of VEGFB in blood was associated with better baseline memory (p=0.008). Notably, we observed that higher gene expression of VEGFB in blood was associated with lower expression of VEGFB in the brain (r=−0.19, p=0.02). Together, these results suggest that the VEGFB, FLT4, and PGF alterations in the AD brain may be detectable in the blood compartment.

This is a review of recent research exploring and extending present-day quantum computing capabilities for fusion energy science applications. We begin with a brief tutorial on both ideal and open quantum dynamics, universal quantum computation, and quantum algorithms. Then, we explore the topic of using quantum computers to simulate both linear and nonlinear dynamics in greater detail. Because quantum computers can only efficiently perform linear operations on the quantum state, it is challenging to perform nonlinear operations that are generically required to describe the nonlinear differential equations of interest. In this work, we extend previous results on embedding nonlinear systems within linear systems by explicitly deriving the connection between the Koopman evolution operator, the Perron-Frobenius evolution operator, and the Koopman-von Neumann evolution (KvN) operator. We also explicitly derive the connection between the Koopman and Carleman approaches to embedding. Extension of the KvN framework to the complex-analytic setting relevant to Carleman embedding, and the proof that different choices of complex analytic reproducing kernel Hilbert spaces depend on the choice of Hilbert space metric are covered in the appendices. Finally, we conclude with a review of recent quantum hardware implementations of algorithms on present-day quantum hardware platforms that may one day be accelerated through Hamiltonian simulation. We discuss the simulation of toy models of wave-particle interactions through the simulation of quantum maps and of wave-wave interactions important in nonlinear plasma dynamics., 42 pages; 12 figures; invited paper at the 2021-2022 International Sherwood Fusion Theory Conference

Experimental limitations such as optical loss and noise have prevented entanglement-enhanced measurements from demonstrating a significant quantum advantage in sensitivity. Holland-Burnett entangled states can mitigate these limitations and still present a quantum advantage in sensitivity. Here we model a fiber-based Mach-Zehnder interferometer with internal loss, detector efficiency, and external phase noise and without pure entanglement. This model features a practical fiber source that transforms the two-mode squeezed vacuum (TMSV) into Holland-Burnett entangled states. We predict that a phase sensitivity 28% beyond the shot noise limit is feasible with current technology. Simultaneously, a TMSV source can provide about 25 times more photon flux than other entangled sources. This system will make fiber-based quantum-enhanced sensing accessible and practical for remote sensing and probing photosensitive materials.

Transport, separation, and merging of trapped ion crystals are essential operations for most large-scale quantum computing architectures. In this Letter, we develop a theoretical framework that describes the dynamics of ions in time-varying potentials with a motional squeeze operator, followed by a motional displacement operator. Using this framework, we develop a new, general protocol for trapped ion transport, separation, and merging. We show that motional squeezing can prepare an ion wave packet to enable transfer from the ground state of one trapping potential to another. The framework and protocol are applicable if the potential is harmonic over the extent of the ion wave packets at all times. As illustrations, we discuss two specific operations: changing the strength of the confining potential for a single ion and separating same-species ions with their mutual Coulomb force. Both of these operations are, ideally, free of residual motional excitation.

Berni Julian Alder, one of the leading figures in the invention of molecular dynamics simulations used for a wide array of problems in physics and chemistry, died on September 7, 2020. His career, spanning more than 65 years, transformed statistical mechanics, many body physics, the study of chemistry, and the microscopic dynamics of fluids, by making atomistic computational simulation (in parallel with traditional theory and experiment) a new pathway to unexpected discoveries. Among his many honors, the CECAM prize, recognizing exceptional contributions to the simulation of the microscopic properties of matter, is named for him. He was awarded the National Medal of Science by President Obama in 2008. Berni Julian Alder in 2015. Image credit: Lawrence Livermore National Laboratory. Alder was born to Ludwig Adler and Otillie nee Gottschalk in Duisburg, Germany on September 9, 1925. Alder’s father Ludwig was a chemist who worked in the German aluminum industry. When the Nazis came to power in 1933, Alder, his parents, elder brother Henry, and twin brother Charles fled to Zurich, Switzerland. In 1941, they further emigrated to the United States (becoming “Alders” in the process), where they settled in Berkeley, California. From then on, he and his family lived and worked in the Bay Area, which they considered their “slice of heaven.” Alder completed his senior year of high school there and then did his undergraduate studies at the University of California, Berkeley. Alder’s education was interrupted by his service in the … [↵][1]1To whom correspondence may be addressed. Email: libby1{at}llnl.gov. [1]: #xref-corresp-1-1

Fiber-based interferometry with entangled photons can provide sub-shot-noise resolution, which is ideal for photon-starved applications. Simulations demonstrate that measurements with realistic losses and other imperfections show quantum-enhanced phase resolution for practical applications.

Filtered diode array spectrometers are routinely employed to infer the temporal evolution of spectral power from x-ray sources, but uniquely extracting spectral content from a finite set of broad, spectrally overlapping channel spectral sensitivities is decidedly nontrivial in these under-determined systems. We present the use of genetic algorithms to reconstruct a probabilistic spectral intensity distribution and compare to the traditional approach most commonly found in the literature. Unlike many of the previously published models, spectral reconstructions from this approach are neither limited by basis functional forms nor do they require a priori spectral knowledge. While the original intent of such measurements was to diagnose the temporal evolution of spectral power from quasi-blackbody radiation sources—where the exact details of spectral content were not thought to be crucial—we demonstrate that this new technique can greatly enhance the utility of the diagnostic by providing more physical spectra and improved robustness to hardware configuration for even strongly non-Planckian distributions.

As a milestone for general-purpose computing machines, we demonstrate that quantum processors can be programmed to efficiently simulate dynamics that are not native to the hardware. Moreover, on noisy devices without error correction, we show that simulation results are significantly improved when the quantum program is compiled using modular gates instead of a restricted set of standard gates. We demonstrate the general methodology by solving a cubic interaction problem, which appears in nonlinear optics, gauge theories, as well as plasma and fluid dynamics. To encode the nonnative Hamiltonian evolution, we decompose the Hilbert space into a direct sum of invariant subspaces in which the nonlinear problem is mapped to a finite-dimensional Hamiltonian simulation problem. In a three-states example, the resultant unitary evolution is realized by a product of ~20 standard gates, using which ~10 simulation steps can be carried out on state-of-the-art quantum hardware before results are corrupted by decoherence. In comparison, the simulation depth is improved by more than an order of magnitude when the unitary evolution is realized as a single cubic gate, which is compiled directly using optimal control. Alternatively, parametric gates may also be compiled by interpolating control pulses. Modular gates thus obtained provide high-fidelity building blocks for quantum Hamiltonian simulations., 4 figures. pages 1-6 are main text and bibliography, and pages 7-8 are supplemental material

The dominant error sources for state-of-the-art laser-free trapped-ion entangling gates are decoherence of the qubit state and the ion motion. The effect of these decoherence mechanisms can be suppressed with additional control fields, or with techniques that have the disadvantage of reducing gate speed. Here, we propose using a near-motional-frequency magnetic field gradient to implement a laser-free gate that is simultaneously resilient to both types of decoherence, does not require additional control fields, and has a relatively small cost in gate speed.

High-harmonic generation is a universal response of matter to strong femtosecond laser fields, coherently upconverting light to much shorter wavelengths. Optimizing the conversion of laser light into soft x-rays typically demands a trade-off between two competing factors. Because of reduced quantum diffusion of the radiating electron wave function, the emission from each species is highest when a short-wavelength ultraviolet driving laser is used. However, phase matching—the constructive addition of x-ray waves from a large number of atoms—favors longer-wavelength mid-infrared lasers.We identified a regime of high-harmonic generation driven by 40-cycle ultraviolet lasers in waveguides that can generate bright beams in the soft x-ray region of the spectrum, up to photon energies of 280 electron volts. Surprisingly, the high ultraviolet refractive indices of both neutral atoms and ions enabled effective phase matching, even in a multiply ionized plasma.We observed harmonics with very narrow linewidths, while calculations show that the x-rays emerge as nearly time-bandwidth–limited pulse trains of ~100 attoseconds., The experimental work was done at JILA, supported by Army Research Office grant WN11NF-13-1-0259, an NSF PFI AIR award, and U.S. Department of Energy (DOE) grant DE-SC0008803 (M.M.M., T.P., and H.C.K.). Theory was supported by a Marie Curie International Outgoing Fellowship within the EU Seventh Framework Programme for Research and Technological Development (2007–2013) under REA grant agreement 328334 (C.H.-G.); Junta de Castilla y León (SA116U13, UIC016) and MINECO (FIS2013-44174-P) (C.H.-G. and L.P.); NSF grants PHY-1125844 and PHY-1068706 and AFOSR MURI “Mathematical Modeling and Experimental Validation of Ultrafast Light-Matter Coupling associated with Filamentation in Transparent Media” grant FA9550-10-1-0561 (A.J.-B., R.J.L., X.G., A.L.G., M.M.M., and H.C.K.); Ministry of Science and Technology, Taiwan, grant 102-2112-M-007-025-MY3 (M.-C.C.); U.S. Department of Energy, Division of Chemical Sciences, Atomic, Molecular and Optical Sciences Program (A.B.); and DOE Office of Fusion Energy, HED Laboratory Plasmas program, grant AT5015033 (S.B.L., M.F., and J.A.G.). Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security LLC for DOE, National Nuclear Security Administration, under contract DE-AC52-07NA27344, LLNL-JRNL-676693. T.P., D.P., M.M.M., and H.C.K. have filed a patent on “Generation of VUV, EUV, X-ray Light Using VUV-UV-VIS Lasers,” U.S. patent application 61873794 (2013)/US 20150063385 (2015).

We present a general theory for laser-free entangling gates with trapped-ion hyperfine qubits, using either static or oscillating magnetic-field gradients combined with a pair of uniform microwave fields symmetrically detuned about the qubit frequency. By transforming into a `bichromatic' interaction picture, we show that either ${\hat{\sigma}_{\phi}\otimes\hat{\sigma}_{\phi}}$ or ${\hat{\sigma}_{z}\otimes\hat{\sigma}_{z}}$ geometric phase gates can be performed. The gate basis is determined by selecting the microwave detuning. The driving parameters can be tuned to provide intrinsic dynamical decoupling from qubit frequency fluctuations. The ${\hat{\sigma}_{z}\otimes\hat{\sigma}_{z}}$ gates can be implemented in a novel manner which eases experimental constraints. We present numerical simulations of gate fidelities assuming realistic parameters.

We make direct observations of localized light absorption in a single nanostructure irradiated by a strong femtosecond laser field, by developing and applying a technique that we refer to as plasma explosion imaging. By imaging the photoion momentum distribution resulting from plasma formation in a laser-irradiated nanostructure, we map the spatial location of the highly localized plasma and thereby image the nanoscale light absorption. Our method probes individual, isolated nanoparticles in vacuum, which allows us to observe how small variations in the composition, shape, and orientation of the nanostructures lead to vastly different light absorption. Here, we study four different nanoparticle samples with overall dimensions of ∼100 nm and find that each sample exhibits distinct light absorption mechanisms despite their similar size. Specifically, we observe subwavelength focusing in single NaCl crystals, symmetric absorption in TiO2 aggregates, surface enhancement in dielectric particles containing a single gold nanoparticle, and interparticle hot spots in dielectric particles containing multiple smaller gold nanoparticles. These observations demonstrate how plasma explosion imaging directly reveals the diverse ways in which nanoparticles respond to strong laser fields, a process that is notoriously challenging to model because of the rapid evolution of materials properties that takes place on the femtosecond time scale as a solid nanostructure is transformed into a dense plasma.

First principles microphysics models are essential to the design and analysis of high energy density physics experiments. Using experimental data to investigate the underlying physics is also essential, particularly when simulations and experiments are not consistent with each other. This is a difficult task, due to the large number of physical models that play a role, and due to the complex (and as a result, noisy) nature of the experiments. This results in a large number of parameters that make any inference a daunting task; it is also very important to consistently treat both experimental and prior understanding of the problem. In this paper we present a Bayesian method that includes both these effects, and allows the inference of a set of modifiers which have been constructed to give information about microphysics models from experimental data. We pay particular attention to radiation transport models. The inference takes into account a large set of experimental parameters and an estimate of the prior knowledge through a modified $\chi^{2}$ function, which is minimised using an efficient genetic algorithm. Both factors play an essential role in our analysis. We find that although there is evidence of inaccuracies in off-line calculations of X ray drive intensity and Ge $L$ shell absorption, modifications to radiation transport are unable to reconcile differences between 1D HYDRA simulations and the experiment.

The influence of an external test mass on the phase of the signal of an atom interferometer is studied theoretically. Using traditional techniques in atom optics based on the density matrix equations in the Wigner representation, we are able to extract the various contributions to the phase of the signal associated with the classical motion of the atoms, the quantum correction to this motion resulting from atomic recoil that is produced when the atoms interact with Raman field pulses and quantum corrections to the atomic motion that occur in the time between the Raman field pulses. By increasing the effective wave vector associated with the Raman field pulses using modified field parameters, we can increase the sensitivity of the signal to the point where such quantum corrections can be measured. The expressions that are derived can be evaluated numerically to isolate the contribution to the signal from an external test mass. The regions of validity of the exact and approximate expressions are determined.

This article supports a satirical reading of Book 11 of the Golden Ass by showing a previously unrecognized way in which Apuleius undermines Isis and her priests. An analysis of moon and mirror imagery in Apuleius' novel as well as his philosophical and rhetorical works will show how he exploits an inherent difficulty in Isis' lunar symbol and the mirrors used to represent it. The moon-goddess Isis will turn out to be an opportunistic fraud who, like a mirror, reflects light without producing her own. the first ten Books of ApuLeius' Golden Ass are a whirlwind of sexual, magical, and violent escapades—the topics covered include witchcraft, necromancy, banditry, con-artistry, divine comedy, murder, incest, adultery, man-eating monsters, and, of course, bestiality. But, in his concluding Book 11, Apuleius abruptly drops this comedic subject matter. He takes up instead a story of religious conversion: the narrator Lucius is initiated into Isis-cult after he awakes one night and prays to an unusually beautiful moon. Perry (1967, 244) famously called Book 11 "a piece of solemn pageantry (working) as ballast to offset the prevailing levity of the preceding ten books." 1 More recently, we have had what we might call more attractive suggestions on how to read Lucius' sudden religious awakening. Some scholars have maintained the unity of the novel by locating moments in the earlier comedic tales that can be seen as preparing for a serious Book 11. 2 Others have rejected this serious

Phaedrus wrote two fables featuring Roman emperors. In Fable 2.5 we find Emperor Tiberius giving a busybody his deserved come-uppance, and in Fable 3.10 Augustus miraculously solves a murder-suicide case. Yet couched among so many of Phaedrus’ fables that criticize authority figures, these positive portrayals of the emperors come as a surprise to the reader and present a significant problem of interpretation. In exploring the different possible readings of the two poems, this paper follows Phaedrus through a complex interpretive maze and shows how the fabulist’s own self-portrayal intersects with and colors his portrayal of the first two Roman emperors.

We combine an aerodynamic lens with a velocity-map-imaging spectrometer to make the first measurements of ultrafast dynamics in individual nanoplasmas. By using two laser pulses (800 and 400 nm) delayed by several picoseconds, we find that we can generate and control shock wave propagation in nanoplasmas, confirming a decade of theoretical predictions. Additionally, we observe pronounced asymmetries in the photoion angular distributions resulting from nanoparticles of different structure and composition, demonstrating the ability to observe nanoscale light absorption at laser intensities near the damage threshold.

The young Teller applied the new quantum mechanics theory to understanding molecules. In later years, his interest in nuclear fusion and matter at high energy density meshed naturally with his role in national defense.

The PHENIX tracking system consists of Drift Chambers (DC), Pad Chambers (PC) and the Time Expansion Chamber (TEC). PC1/DC and PC2/TEC/PC3 form the inner and outer tracking units, respectively. These units link the track segments that transverse the RICH and extend to the EMCal. The DC measures charged particle trajectories in the r-phi direction to determine P-T of the particles and the invariant mass of particle pairs. The PCs perform 3D spatial point measurements for pattern recognition and longitudinal momentum reconstruction and provide spatial resolution of a few mm in both r-phi and z. The TEC tracks particles passing through the region between the RICH and the EMCal. The design and operational parameters of the detectors are presented and running experience during the first year of data taking with PHENIX is discussed. The observed spatial and momentum resolution is given which imposes a limitation on the identification and characterization of charged particles in various momentum ranges. (C) 2002 Published by Elsevier Science B.V.

In a novel experiment that images the momentum distribution of individual, isolated 100-nm-scale plasmas, we make the first experimental observation of shock waves in nanoplasmas. We demonstrate that the introduction of a heating pulse prior to the main laser pulse increases the intensity of the shock wave, producing a strong burst of quasi-monochromatic ions with an energy spread of less than 15%. Numerical hydrodynamic calculations confirm the appearance of accelerating shock waves, and provide a mechanism for the generation and control of these shock waves. This observation of distinct shock waves in dense plasmas enables the control, study, and exploitation of nanoscale shock phenomena with tabletop-scale lasers., 8 pages of manuscript, 9 pages of supplemental information, total 17 pages

The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials., Petawatt laser-matter interactions could open the way to fusion energy or compact particular accelerators, but predicting the amount of light absorbed in these interactions is challenging. New analysis by Levy et al. reveals the theoretical upper and lower limits of this absorption.

We study the ratio of viscosity to entropy density in Yukawa one-component plasmas as a function of coupling parameter at fixed screening, and in realistic warm dense matter models as a function of temperature at fixed density. In these two situations, the ratio is minimized for values of the coupling parameters that depend on screening, and for temperatures that in turn depend on density and material. In this context, we also examine Rosenfeld arguments relating transport coefficients to excess reduced entropy for Yukawa one-component plasmas. For these cases we show that this ratio is always above the lower-bound conjecture derived from string theory ideas. (C) 2014 Elsevier B.V. All rights reserved.

We combine an aerodynamic lens with a velocity-map-imaging spectrometer to make the first measurements of shock wave generation and ultrafast dynamics in individual nanoplasmas, confirming a decade of theoretical predictions.

A rigorous general theory based on non-equilibrium thermodynamics is developed to treat atoms in a steady-state non-equilibrium plasma with strong radiation environment. The atomic radiative properties are described by a linear response matrix, which relates the emission/absorption coefficients to the surrounding radiation environment. The response matrix is calculated by solution of the usual rate equations with special boundary conditions. There is evidence that the range of linear response is large. According to the general theory of non-equilibrium thermodynamics the response matrix must be symmetric and this symmetry gives a powerful test for NLTE codes. In this paper we prove that excited-state populations in a steady-state near-LTE plasma are characterized by the principle of minimum entropy production and derive the exact formula for the response matrix.

We present Experiment 864's measurement of invariant antideuteron yields in 11.5A GeV/c Au + Pt collisions. The analysis includes 250 million triggers representing 14 billion 10% central interactions sampled for events with high mass candidates. We find (1/2 pi pt) d^(2)N/dydpt = 3.5 +/- 1.5 (stat.) +0.9,-0.5 (sys.) x 10^(-8) GeV^(-2)c^(2) for 1.8=0.35 GeV/c (y(cm)=1.6) and 3.7 +/- 2.7 (stat.) +1.4,-1.5 (sys.) x 10^(-8) GeV^(-2)c^(2) for 1.4=0.26 GeV/c, and a coalescence parameter B2-bar of 4.1 +/- 2.9 (stat.) +2.3,-2.4 (sys.) x 10^(-3) GeV^(2)c^(-3). Implications for the coalescence model and antimatter annihilation are discussed., Comment: 8 pages, 4 figures, Latex, submitted to Phys. Rev. Lett

The Nova laser facility has been used to produce matter in extreme conditions in the laboratory. The plasmas are produced by imploding spherical capsules filled with deuterium and trace amounts of Ar. A spectroscopic study of these indirectly driven, inertially confined plasmas provides measurements of the plasma parameters as a function of time. Multiple diagnostics measure peak ne ~ 1 × 1024 cm-3 and Te ~ 1000 eV. A series of experiments have demonstrated that the results are reliable and reproducible. These experiments are designed to produce laboratory implosions that can serve as a "testbed" for high energy density matter. Measuring temperature gradients are the next step so that they can become sources suitable for studying physics such as high-density plasma effects or radiative cooling.

We present results from Experiment 864 for antiproton production and antideuteron limits in Au + Pb collisions at 11.5 GeV/c per nucleon. We have measured invariant multiplicities for antiprotons for rapidities 1.4{lt}y{lt}2.4 at low transverse momentum as a function of collision geometry. When compared with the results from Experiment 878 our measurements suggest a significant contribution to the measured antiproton yield from the decay of strange antibaryons. We have also searched for antideuterons and see no statistically significant signal. Thus, we set upper limits on the production at approximately 3{times}10{sup {minus}7} per 10{percent} highest multiplicity Au+Pb interaction. {copyright} {ital 1999} {ital The American Physical Society}

The E864 experiment at the AGS is designed to carry out high sensitivity searches for a variety of possible new particles using relativistic heavy ion Au beams on Pb and Pt targets. In order to reach the desired sensitivities, a level-2 “late energy” trigger was built to select events in which a heavy particle is detected in a hadronic calorimeter with deposited energy and time-of-flight from the target exceeding preset values. The physics motivation for the trigger is discussed and and details of its hardware and software design are given. Performance results from recent E864 data taking runs are presented.

A large hadronic lead scintillating fiber calorimeter has been built and integrated into the AGS experiment E864 [C. Pruneau et al., E864 Collaboration, Proc. 6th Internal. Conf. on Calorimetry in High Energy Physics, 1996, Frascati, Italy; F. Rotondo et al., E864 Collaboration, Proc. Quark Matter'96, Heidelberg, Germany, 20 May 1996] spectrometer to provide an independent measurement of the mass of particles produced in heavy ion collisions. The “spaghetti-type” calorimeter design and construction techniques are described in detail. Results from a prototype and the full implementation of the calorimeter are reported. The hadronic energy resolution of the calorimeter is found to be 6E/E = 0.035(± 0.005) + 0.344(± 0.008)/trE/GeV, in very good agreement with a FLUKA calculation. The hadronic time resolution is measured to be better than 400 ps. The combined calorimeter energy and time signals provide for a mass determination with good resolution. The mass resolution scales as δm/m = 0.026 + 0.347/√E(GeV) for velocities v/c

We describe the role for the next-generation “superlasers” in the study of matter under extremely high-energy-density conditions in comparison with previous uses of nuclear explosives for this purpose. As examples, we focus on three important areas of physics that have unresolved issues that must be addressed by experiment: equations of state, hydrodynamic instabilities, and the transport of radiation. We describe some of the advantages the large lasers will have in a comprehensive, laboratory-based experimental program.

We present results of a search for strange quark matter (strangelets) in 11.5 A GeV/c Au+Pb collisions from the 1994 and 1995 runs of experiment E864 at Brookhaven's AGS. We observe no strangelet candidates and set a 90% confidence level upper limit of approximately 3x10**-8 per 10% central interaction for the production of |Z|=1 and |Z|=2 strangelets over a large mass range and with metastable lifetimes of about 50 ns or more. These results place constraints primarily on quark-gluon plasma based production models for strangelets.

We present the first results from the E864 Collaboration on the production of antiprotons in 10{percent} central 11.5A GeV /c Au+Pb nucleus collisions at the Brookhaven Alternating Gradient Synchrotron. We report invariant multiplicities for antiproton production in the kinematic region 1.4{lt}y{lt}2.2 and 50{lt} p{sub T}{lt} 300 MeV/c , and compare our data with a first collision scaling model and previously published results from the E878 Collaboration. The differences between the E864 and E878 antiproton measurements and the implications for antihyperon production are discussed. {copyright} {ital 1997} {ital The American Physical Society}