Relationship between Hexokinase and the Aquaporin PIP1 in the Regulation of Photosynthesis and Plant Growth

Increased expression of the aquaporin NtAQP1, which is known to function as a plasmalemma channel for CO2 and water, increases the rate of both photosynthesis and transpiration. In contrast, increased expression of Arabidopsis hexokinase1 (AtHXK1), a dual-function enzyme that mediates sugar sensing, decreases the expression of photosynthetic genes and the rate of transpiration and inhibits growth. Here, we show that AtHXK1 also decreases root and stem hydraulic conductivity and leaf mesophyll CO2 conductance (gm). Due to their opposite effects on plant development and physiology, we examined the relationship between NtAQP1 and AtHXK1 at the whole-plant level using transgenic tomato plants expressing both genes simultaneously. NtAQP1 significantly improved growth and increased the transpiration rates of AtHXK1-expressing plants. Reciprocal grafting experiments indicated that this complementation occurs when both genes are expressed simultaneously in the shoot. Yet, NtAQP1 had only a marginal effect on the hydraulic conductivity of the double-transgenic plants, suggesting that the complementary effect of NtAQP1 is unrelated to shoot water transport. Rather, NtAQP1 significantly increased leaf mesophyll CO2 conductance and enhanced the rate of photosynthesis, suggesting that NtAQP1 facilitated the growth of the double-transgenic plants by enhancing mesophyll conductance of CO2

Broadband Spectral Investigations of SGR J1550-5418 Bursts

We present the results of our broadband spectral analysis of 42 SGR J1550-5418 bursts simultaneously detected with the Swift/X-ray Telescope (XRT) and the Fermi/Gamma-ray Burst Monitor (GBM), during the 2009 January active episode of the source. The unique spectral and temporal capabilities of the XRT Windowed Timing mode have allowed us to extend the GBM spectral coverage for these events down to the X-ray domain (0.5-10 keV). Our earlier analysis of the GBM data found that the SGR J1550-5418 burst spectra were described equally well with a Comptonized model or with two blackbody functions; the two models were statistically indistinguishable. Our new broadband (0.5 - 200 keV) spectral fits show that, on average, the burst spectra are better described with two blackbody functions than with the Comptonized model. Thus, our joint XRT/GBM analysis clearly shows for the first time that the SGR J1550-5418 burst spectra might naturally be expected to exhibit a more truly thermalized character, such as a two-blackbody or even a multi-blackbody signal. Using the Swift and RXTE timing ephemeris for SGR J1550-5418 we construct the distribution of the XRT burst counts with spin phase and find that it is not correlated with the persistent X-ray emission pulse phase from SGR J1550-5418. These results indicate that the burst emitting sites on the neutron star need not be co-located with hot spots emitting the bulk of the persistent X-ray emission. Finally, we show that there is a significant pulse phase dependence of the XRT burst counts, likely demonstrating that the surface magnetic field of SGR J1550-5418 is not uniform over the emission zone, since it is anticipated that regions with stronger surface magnetic field could trigger bursts more efficiently.Comment: accepted for publication in The Astrophysical Journa

Psychological Perspectives on the Presentation of Video Evidence: How Perceivers Weight What is Seen and Unseen

Video evidence is proliferating in the courtroom, outpacing the incremental advances in policies governing its use. Psychological research on attention and perception indicates that people are vulnerable to numerous biases in how they interpret video. The dynamic format of such evidence directs attention in distinct ways, and the visual system selectively captures some pieces of information at the expense of others. Thus, perceivers who must make decisions about video evidence are vulnerable to overweighting the information they see, underweighting the information they do not see, and being overconfident about their interpretation of what they see. We marshal emerging research on attention and cognition to consider perceivers’ vulnerabilities to video evidence. Further, we ask whether instruction interventions may disrupt biases in decision-making about video evidence. We present pilot data suggesting that instructions to consider information missing from a scene might bridge the gap between disparate perceptions of body camera and dashcam footage of the same scene

The Case for Anisotropic Afterglow Efficiency within Gamma-Ray Burst Jets

Early X-ray afterglows recently detected by {\it Swift} frequently show a phase of very shallow flux decay lasting from $\sim 10^{2.5}$s up to $\sim 10^4$s, followed by a steeper, more familiar decay. We suggest that the flat early part of the light curve may be a combination of the decaying tail of the prompt emission and the delayed onset of the afterglow emission observed from viewing angles slightly outside the edge of the region within the jet with prominent afterglow emission, as predicted previously. This would imply that a significant fraction of viewers get very little external shock energy along their line of sight, and, therefore, see a very high $\gamma$-ray to kinetic energy ratio at early times. The early flat phase in the afterglow light curve implies, in a rather robust and model independent manner, a very large $\gamma$-ray efficiency, typically $\gtrsim 90$, which is very difficult to extract from baryons by internal shocks.Comment: Revised version, submitted to Ap

The Gamma Ray Burst section of the White Paper on the Status and Future of Very High Energy Gamma Ray Astronomy: A Brief Preliminary Report

Original paper can be found at: http://proceedings.aip.org/proceedings/ Copyright American Institute of Physics DOI: 10.1063/1.2943545otherPeer reviewe

Detection of spectral evolution in the bursts emitted during the 2008-2009 active episode of SGR J1550 - 5418

In early October 2008, the Soft Gamma Repeater SGRJ1550 - 5418 (1E 1547.0 - 5408, AXJ155052 - 5418, PSR J1550 - 5418) became active, emitting a series of bursts which triggered the Fermi Gamma-ray Burst Monitor (GBM) after which a second especially intense activity period commenced in 2009 January and a third, less active period was detected in 2009 March-April. Here we analyze the GBM data all the bursts from the first and last active episodes. We performed temporal and spectral analysis for all events and found that their temporal characteristics are very similar to the ones of other SGR bursts, as well the ones reported for the bursts of the main episode (average burst durations \sim 170 ms). In addition, we used our sample of bursts to quantify the systematic uncertainties of the GBM location algorithm for soft gamma-ray transients to < 8 deg. Our spectral analysis indicates significant spectral evolution between the first and last set of events. Although the 2008 October events are best fit with a single blackbody function, for the 2009 bursts an Optically Thin Thermal Bremsstrahlung (OTTB) is clearly preferred. We attribute this evolution to changes in the magnetic field topology of the source, possibly due to effects following the very energetic main bursting episode.Comment: 17 pages, 7 figures, 2 table

A Fair Share: Effects of Disparity, Allocation Strategy, and System Justification on Perceptions of Policy Support in the Education Domain

Utilizing experimental methods across a pilot and two studies, we explore and contrastt he relationship between system-justifying attitudes and fairness perceptions of and support for redistributive policies based on theoretical accounts of distributive justice, highlighting three allocation strategies: equality, equity and need. We began our investigation with a test across multiple policy domains (e.g., health care, education, employment) to examine broad associations between system justification and policy support. Then, we chose one specific domain – education – to narrow our focus on and designed two experimental studies to test more complex models of the interaction between system justification and the type of distributive justice on support and fairness perceptions. Results indicate that as system-justifying attitudes increase, so does the level of support and perception of fairness of policies based on equality or equity. Conversely, there is no relationship between system justification and support or fairness when considering a need-based policy in the education domain

Burst and persistent emission properties during the recent active episode of the anomalous x-ray pulsar 1E 1841-045

Copyright American Astronomical SocietyThe Swift/Burst Alert Telescope detected the first burst from 1E 1841-045 in 2010 May with intermittent burst activity recorded through at least 2011 July. Here we present Swift and Fermi/Gamma-ray Burst Monitor observations of this burst activity and search for correlated changes to the persistent X-ray emission of the source. The T-90 durations of the bursts range between 18 and 140 ms, comparable to other magnetar burst durations, while the energy released in each burst ranges between (0.8-25) x 10(38) erg, which is on the low side of soft gamma repeater bursts. We find that the bursting activity did not have a significant effect on the persistent flux level of the source. We argue that the mechanism leading to this sporadic burst activity in 1E 1841-045 might not involve large-scale restructuring (either crustal or magnetospheric) as seen in other magnetar sources.Peer reviewedFinal Accepted Versio

A fair share: Effects of disparity, allocation strategy and system justification on perceptions of policy support in the education domain

Inequality in the United States has been rising for decades. According to the U.S. Federal Reserve, as of 2023, the top 10% of wealthiest households hold 69% of all wealth while the bottom 50% of households only hold 2.5% of all wealth (Federal Reserve Bank of St. Louis, 2023). Recently, such disparities have been put into stark relief, as the COVID-19 pandemic increased objective inequality within the United States; those low in socioeconomic status (SES) have a higher risk of contracting COVID-19, are more likely to have their housing and employment situations completely upended and have limited access to health care than those high in SES (Patel et al., 2020). Even in the face of such stark inequality, people are often either unaware, unwilling to see or disagree about whether such disparities are indeed unfair and therefore fail to agree on optimal ways to ensure fair access to resources