Does Use of Gypsum Improve Soil Structure in Kentucky?

Gypsum is sometimes recommended as a soil amendment in order to improve structure. Although this practice is often used for reclamation of sodic soils (Na+ saturated) in the western USA, it\u27s value in improving soil structure in Kentucky is questionable. The following discussion explains way

SN~1991T: Reflections of Past Glory

We have obtained photometry and spectra of SN~1991T which extend more than 1000 days past maximum light, by far the longest a SN~Ia has been followed. Although SN~1991T exhibited nearly normal photometric behavior in the first 400 days following maximum, by 600 days its decline had slowed, and by 950~days the supernova brightness was consistent with a constant apparent magnitude of $m_B=21.30$. Spectra near maximum showed minor variations on the SN~Ia theme which grew less conspicuous during the exponential decline. At 270 days the nebular spectrum was composed of Fe and Co lines common to SNe~Ia. However, by 750 days past maximum light, these lines had shifted in wavelength, and were superimposed on a strong blue continuum. The luminosity of SN~1991T at 950 days is more than $9.0\times10^{38}(D/13~{\rm Mpc})^2$~ergs~s$^{-1}$ with a rate of decline of less than $0.04$ mags/100~days. We show that this emission is likely to be light that was emitted by SN~1991T near maximum light which has reflected from foreground dust, much like the light echos observed around SN~1987A.Comment: 15 pages (includes figures and tables) uuencoded compressed postscript, CfA Preprint - To Appear in ApJ

The Effect of Oil Well Brines on Agricultural Fields and Water

What is Brine and Where Does it Come From? Brine is the salty water trapped in rock formations associated with oil and gas deposits. It consists mostly of sodium chloride but can also contain other things such as organics, bromide, some heavy metals and boron. Its source as a pollutant is usually oil stripper wells which produce less than 10 barrels of oil per day with typically a 10:1 ratio of brine to oil. Such wells are distributed throughout Kentucky and are often located on farmland. In some cases, brine rises to the land surface even where no oil wells are present

Phase Coexistence Near a Morphotropic Phase Boundary in Sm-doped BiFeO3 Films

We have investigated heteroepitaxial films of Sm-doped BiFeO3 with a Sm-concentration near a morphotropic phase boundary. Our high-resolution synchrotron X-ray diffraction, carried out in a temperature range of 25C to 700C, reveals substantial phase coexistence as one changes temperature to crossover from a low-temperature PbZrO3-like phase to a high-temperature orthorhombic phase. We also examine changes due to strain for films greater or less than the critical thickness for misfit dislocation formation. Particularly, we note that thicker films exhibit a substantial volume collapse associated with the structural transition that is suppressed in strained thin films

Extending Phenomenological Crystal-Field Methods to C1C_1 Point-Group Symmetry: Characterization of the Optically-Excited Hyperfine Structure of 167^{167}Er3+^{3+}:Y2_2SiO5_5

We show that crystal-field calculations for $C_1$ point-group symmetry are possible, and that such calculations can be performed with sufficient accuracy to have substantial utility for rare-earth based quantum information applications. In particular, we perform crystal-field fitting for a C$_1$-symmetry site in $^{167}$Er$^{3+}$:Y$_2$SiO$_5$. The calculation simultaneously includes site-selective spectroscopic data up to 20,000 cm$^{-1}$, rotational Zeeman data, and ground- and excited-state hyperfine structure determined from high-resolution Raman-heterodyne spectroscopy on the 1.5 $\mu$m telecom transition. We achieve an agreement of better than 50 MHz for assigned hyperfine transitions. The success of this analysis opens the possibility of systematically evaluating the coherence properties, as well as transition energies and intensities, of any rare-earth ion doped into Y$_2$SiO$_5$ .Comment: 6 pages, plus 5 pages in supplementary information, 4 figures tota

ARPES Study of the Metal-Insulator Transition in Bismuth Cobaltates

We present an angle-resolved photoemission spectroscopy (ARPES) study of a Mott-Hubbard-type bismuth cobaltate system across a metal-insulator transition. By varying the amount of Pb substitution, and by doping with Sr or Ba cation, a range of insulating to metallic properties is obtained. We observe a systematic change in the spectral weight of the coherent and incoherent parts, accompanied by an energy shift of the incoherent part. The band dispersion also shows the emergence of a weakly dispersing state at the Fermi energy with increasing conductivity. These changes correspond with the changes in the temperature-dependent resistivity behavior. We address the nature of the coherent-incoherent parts in relation to the peak-dip-hump feature seen in cuprates superconductors

All-sky Relative Opacity Mapping Using Night Time Panoramic Images

An all-sky cloud monitoring system that generates relative opacity maps over many of the world's premier astronomical observatories is described. Photometric measurements of numerous background stars are combined with simultaneous sky brightness measurements to differentiate thin clouds from sky glow sources such as air glow and zodiacal light. The system takes a continuous pipeline of all-sky images, and compares them to canonical images taken on other nights at the same sidereal time. Data interpolation then yields transmission maps covering almost the entire sky. An implementation of this system is currently operating through the Night Sky Live network of CONCAM3s located at Cerro Pachon (Chile), Mauna Kea (Hawaii), Haleakala (Hawaii), SALT (South Africa) and the Canary Islands (Northwestern Africa).Comment: Accepted for publication in PAS

Staging superstructures in high-TcT_c Sr/O co-doped La2−x_{2-x}Srx_xCuO4+y_{4+y}

We present high energy X-ray diffraction studies on the structural phases of an optimal high-$T_c$ superconductor La$_{2-x}$Sr$_x$CuO$_{4+y}$ tailored by co-hole-doping. This is specifically done by varying the content of two very different chemical species, Sr and O, respectively, in order to study the influence of each. A superstructure known as staging is observed in all samples, with the staging number $n$ increasing for higher Sr dopings $x$. We find that the staging phases emerge abruptly with temperature, and can be described as a second order phase transition with transition temperatures slightly depending on the Sr doping. The Sr appears to correlate the interstitial oxygen in a way that stabilises the reproducibility of the staging phase both in terms of staging period and volume fraction in a specific sample. The structural details as investigated in this letter appear to have no direct bearing on the electronic phase separation previously observed in the same samples. This provides new evidence that the electronic phase separation is determined by the overall hole concentration rather than specific Sr/O content and concommittant structural details.Comment: 8 pages, incl. 4 figure

Networks of Recurrent Events, a Theory of Records, and an Application to Finding Causal Signatures in Seismicity

We propose a method to search for signs of causal structure in spatiotemporal data making minimal a priori assumptions about the underlying dynamics. To this end, we generalize the elementary concept of recurrence for a point process in time to recurrent events in space and time. An event is defined to be a recurrence of any previous event if it is closer to it in space than all the intervening events. As such, each sequence of recurrences for a given event is a record breaking process. This definition provides a strictly data driven technique to search for structure. Defining events to be nodes, and linking each event to its recurrences, generates a network of recurrent events. Significant deviations in properties of that network compared to networks arising from random processes allows one to infer attributes of the causal dynamics that generate observable correlations in the patterns. We derive analytically a number of properties for the network of recurrent events composed by a random process. We extend the theory of records to treat not only the variable where records happen, but also time as continuous. In this way, we construct a fully symmetric theory of records leading to a number of new results. Those analytic results are compared to the properties of a network synthesized from earthquakes in Southern California. Significant disparities from the ensemble of acausal networks that can be plausibly attributed to the causal structure of seismicity are: (1) Invariance of network statistics with the time span of the events considered, (2) Appearance of a fundamental length scale for recurrences, independent of the time span of the catalog, which is consistent with observations of the ``rupture length'', (3) Hierarchy in the distances and times of subsequent recurrences.Comment: 19 pages, 13 figure

Review: Consumption-stage food waste reduction interventions - What works and how to design better interventions

Food waste prevention has become an issue of international concern, with Sustainable Development Goal 12.3 aiming to halve per capita global food waste at the retail and consumer levels by 2030. However there is no review that has considered the effectiveness of interventions aimed at preventing food waste in the consumption stages of the food system. This significant gap, if filled, could help support those working to reduce food waste in the developed world, providing knowledge of what interventions are specifically effective at preventing food waste. This paper fills this gap, identifying and summarizing food-waste prevention interventions at the consumption/consumer stage of the supply chain via a rapid review of global academic literature from 2006 to 2017. We identify 17 applied interventions that claim to have achieved food waste reductions. Of these, 13 quantified food waste reductions. Interventions that changed the size or type of plates were shown to be effective (up to 57% food waste reduction) in hospitality environments. Changing nutritional guidelines in schools were reported to reduce vegetable waste by up to 28%, indicating that healthy diets can be part of food waste reduction strategies. Information campaigns were also shown to be effective with up to 28% food waste reduction in a small sample size intervention. Cooking classes, fridge cameras, food sharing apps, advertising and information sharing were all reported as being effective but with little or no robust evidence provided. This is worrying as all these methods are now being proposed as approaches to reduce food waste and, except for a few studies, there is no reproducible quantified evidence to assure credibility or success. To strengthen current results, a greater number of longitudinal and larger sample size intervention studies are required. To inform future intervention studies, this paper proposes a standardised guideline, which consists of: (1) intervention design; (2) monitoring and measurement; (3) moderation and mediation; (4) reporting; (5) systemic effects. Given the importance of food-waste reduction, the findings of this review highlight a significant evidence gap, meaning that it is difficult to make evidence-based decisions to prevent or reduce consumption-stage food waste in a cost-effective manner