Total and Nonresidual Concentrations of Selected Elements in Two Soil Series on the Island of Hawaii

Thirty Aridisol soil samples of the Kawaihae soil series on the dry, leeward, northwestern side of the island of Hawaii and 13 Histosol samples of the Papai series on the wet, windward, eastern side of the island were subjected to (1) complete dissolution by a mixture ofHN03, HCl, and HF to determine total concentrations of Co, Cr, Cu, Fe, Mn, Ni, and Zn and (2) extraction of these metals by shaking 10 g soil: 100 mL 0.5M HCl solutions for 16hr to determine nonresidual concentrations. Analyses were performed mainly by flame and electrothermal atomic absorption spectrophotometry. Loss on ignition (LOI) and soil pH were also determined. Total metal concentrations, quantity extracted, LOI, and soil pH were analyzed statistically. Compared to the Histosol, the Aridisol samples typically contain more Co, Cr, Fe, and Mn, less Cu, similar concentrations of Ni and Zn, and have less LOI and higher pH. The Aridisol exhibits a high degree of correlation between total Cr and Ni, while a strong negative correlation occurs between Cu, Mn, Co, and Fe individually with LOI in the Histosol. The mean concentrations of these metals in both soils are significantly greater than those which occur in soils of the conterminous United States. The effectiveness of extraction by the acid solution, as measured by the percentage of metal extracted, is approximately Mn > Co > Cu > Cr > Fe > Zn - Ni for the Aridisol and Cu - Zn > Co - Mn > Fe - Ni > Cr for the Histosol; the difference is attributed to weathering under different climatic conditions. The latter soils exhibit a higher degree of correlation for percentages of metals extracted among the various metals and with LOI

A new, temporarily confined population in the polar cap during the August 27, 1996 geomagnetic field distortion period

On August 27, 1996, a two-hour energetic heavy ion event (∼1 MeV) was detected at 8:25 UT at apogee (∼9 Re and an invariant latitude of ∼80°), by the Charge and Mass Magnetospheric Ion Composition Experiment onboard POLAR. The event, with a maximum spin averaged peak flux of ∼150 particles/(cm²-sr-s-MeV), showed three local peaks corresponding to three localized regions; the ion pitch angle distributions in the three regions were different from an isotropic distribution and different from each other. No comparable flux was observed by the WIND spacecraft. The appearance of lower energy He++ and O \u3e +2 during the event period indicates a solar source for these particles. From region 1 to 2 to 3, the helium energy spectra softened. A distorted magnetic field with three local minima corresponding to the three He peak fluxes was also observed by POLAR. A possible explanation is that the energetic He ions were energized from lower energy helium by a local acceleration mechanism that preferred smaller rigidity ions in the high altitude polar cusp region

Turn-Taking and the Local Management of Conversation in a Highly Simultaneous Computer-Mediated Communication System

Ongoing inquiry in communication technology research includes the questions of whether and how users adapt communication to the relatively restricted codes provided by text-based computer-mediated communication (CMC). This study proposes that adaptations may be affected by the level of simultaneity in messaging that CMC systems afford users. This suggestion is examined through an analysis of the particular conversational management strategies afforded by a fully synchronous computer-mediated communication system in which message transmission is keystroke-by-keystroke. Conversation analyses performed on the transcript of a three-person online conversation suggest several conclusions: Despite the novelty of the system, the CMC users appropriated and adapted many techniques from face-to-face conversations for the local management of conversations, including turn taking, turn allocation, and explicit interruption management. At the time, turn exchange was accomplished by the use of overlapping intermittent talk followed by lengthy strategic pauses, rather than according to the “no gap, no overlap” ideal of spoken conversation. Overall, the computer-mediated exchanges appeared resilient to modality change, and users spontaneously and creatively employed both traditional and technical features of conversation management

Measurement of the small-scale structure of the intergalactic medium using close quasar pairs

The distribution of diffuse gas in the intergalactic medium (IGM) imprints a series of hydrogen absorption lines on the spectra of distant background quasars known as the Lyman-$\alpha$ forest. Cosmological hydrodynamical simulations predict that IGM density fluctuations are suppressed below a characteristic scale where thermal pressure balances gravity. We measured this pressure-smoothing scale by quantifying absorption correlations in a sample of close quasar pairs. We compared our measurements to hydrodynamical simulations, where pressure smoothing is determined by the integrated thermal history of the IGM. Our findings are consistent with standard models for photoionization heating by the ultraviolet radiation backgrounds that reionized the universe.Comment: Accepted for publication on Scienc

Searching for the Imprints of AGN Feedback on the Lyman Alpha Forest Around Luminous Red Galaxies

We explore the potential of using the low-redshift Lyman-$\alpha$ (Ly$\alpha$) forest surrounding luminous red galaxies (LRGs) as a tool to constrain active galactic nuclei (AGN) feedback models. Our analysis is based on snapshots from the Illustris and IllustrisTNG simulations at a redshift of $z=0.1$. These simulations offer an ideal platform for studying the influence of AGN feedback on the gas surrounding galaxies, as they share the same initial conditions and underlying code but incorporate different feedback prescriptions. Both simulations show significant impacts of feedback on the temperature and density of the gas around massive halos. Following our previous work, we adjusted the UV background in both simulations to align with the observed number density of Ly$\alpha$ lines ($\rm dN/dz$) in the intergalactic medium and study the Ly$\alpha$ forest around massive halos hosting LRGs, at impact parameters ($r_{\perp}$) ranging from 0.1 to 100 pMpc. Our findings reveal that $\rm dN/dz$, as a function of $r_{\perp}$, is approximately 1.5 to 2 times higher in IllustrisTNG compared to Illustris up to $r_{\perp}$ of $\sim 10$ pMpc. To further assess whether existing data can effectively discern these differences, we search for archival data containing spectra of background quasars probing foreground LRGs. Through a feasibility analysis based on this data, we demonstrate that ${\rm dN/dz} (r_{\perp})$ measurements can distinguish between feedback models of IllustrisTNG and Illustris with a precision exceeding 12$\sigma$. This underscores the potential of ${\rm dN/dz} (r_{\perp})$ measurements around LRGs as a valuable benchmark observation for discriminating between different feedback models.Comment: 21 pages (including 4 page appendix), Submitted to MNRA

Probabilistic one-time programs using quantum entanglement

It is well known that quantum technology allows for an unprecedented level of data and software protection for quantum computers as well as for quantum-assisted classical computers. To exploit these properties, probabilistic one-time programs have been developed, where the encoding of classical software in small quantum states enables computer programs that can be used only once. Such self-destructing one-time programs facilitate a variety of new applications reaching from software distribution to one-time delegation of signature authority. Whereas first proof-of-principle experiments demonstrated the feasibility of such schemes, the practical applications were limited due to the requirement of using the software on-the-fly combined with technological challenges due to the need for active optical switching and a large amount of classical communication. Here we present an improved protocol for one-time programs that resolves major drawbacks of previous schemes, by employing entangled qubit pairs. This results in four orders of magnitude higher count rates as well the ability to execute a program long after the quantum information exchange has taken place. We demonstrate our protocol over an underground fiber link between university buildings in downtown Vienna. Finally, together with our implementation of a one-time delegation of signature authority this emphasizes the compatibility of our scheme with prepare-and-measure quantum internet networks