Free Fermions Violate the Area Law For Entanglement Entropy

We show that the entanglement entropy associated to a region grows faster than the area of its boundary surface. This is done by proving a special case of a conjecture due to Widom that yields a surprisingly simple expression for the leading behaviour of the entanglement entropy.Comment: Proceedings of the 9th Hellenic School on Elementary Particle Physics and Gravity, Corfu 2009. 4 page

The Wallow Fire and its effects on mixed conifer forest: A comparison with reference conditions. Special report to the Apache-Sitgreaves National Forests, USDA Forest Service, Region 3.

Portions of mixed conifer forests have undergone changes in disturbance regimes, species composition, and forest structure since European settlement and have been impacted by recent landscape-scale fires which have burned large patches with high severity. The Wallow Fire, the largest fire recorded in Arizona, burned a total of 217,741 ha (538,050 ac) in Arizona and New Mexico in the summer of 2011. The purpose of this study was to evaluate high-severity burn patch characteristics in the Wallow fire and determine if they were within the historical range of variability (HRV) for southwestern mixed conifer forests. We used a spatial pattern analysis program to evaluate patch metrics by severity for mixed conifer forests within the Wallow Fire perimeter

Electrical and ultraviolet characterization of 4H-SiC Schottky photodiodes

Fabrication and electrical and optical characterization of 4H-SiC Schottky UV photodetectors with nickel silicide interdigitated contacts is reported. Dark capacitance and current measurements as a function of applied voltage over the temperature range 20 °C – 120 °C are presented. The results show consistent performance among devices. Their leakage current density, at the highest investigated temperature (120 °C), is in the range of nA/cm2 at high internal electric field. Properties such as barrier height and ideality factor are also computed as a function of temperature. The responsivities of the diodes as functions of applied voltage were measured using a UV spectrophotometer in the wavelength range 200 nm - 380 nm and compared with theoretically calculated values. The devices had a mean peak responsivity of 0.093 A/W at 270 nm and −15 V reverse bias

Fact sheet: Planting to restore ponderosa pine sites burned by high-severity fire.

Increases in landscape-scale wildfires in frequent-fire forests over the last several decades have led to management concerns regarding long-term restoration of severely burned sites. In particular, interior areas of large, high-severity patches may lack conifer regeneration for decades (Savage and Mast 2005, Passovoy and Fule 2006, Haire and McGarigal 2010, Roccaforte et al. 2012). A lack of tree regeneration may result in type conversion from sites historically dominated by coniferous forests to persistent non-forested areas (Figure 1) (Barton 2002, Strom and Fule 2007). Based on these concerns, managers have at times aggressively pursued replanting of burned-over sites with conifers, with the result that many planted areas eventually become overly dense with trees to the point that eventually crown fires are bound to recur. To avoid this problem and to assure long-term restoration of forest structure including natural openings, consideration should be given to reestablishment of reference species composition, natural ranges and variability in tree densities, and spatial arrangement of trees in a functional ecosystem

Review Protocol – Final: Do thinning and/or burning treatments on ponderosa pine and related forests in western USA produce restoration of natural fire behaviour?

The aim of this review is to investigate whether thinning and/or burning treatments on ponderosa pine and related forests in western USA produce restoration of natural fire behaviour

Fact sheet: Meta-analysis of treatment effects on fire behavior

Meta-analysis of Treatment Effects on Fire Behavio

Entanglement entropy of fermions in any dimension and the Widom conjecture

We show that entanglement entropy of free fermions scales faster then area law, as opposed to the scaling $L^{d-1}$ for the harmonic lattice, for example. We also suggest and provide evidence in support of an explicit formula for the entanglement entropy of free fermions in any dimension $d$, $S\sim c(\partial\Gamma,\partial\Omega)\cdot L^{d-1}\log L$ as the size of a subsystem $L\to\infty$, where $\partial\Gamma$ is the Fermi surface and $\partial\Omega$ is the boundary of the region in real space. The expression for the constant $c(\partial\Gamma,\partial\Omega)$ is based on a conjecture due to H. Widom. We prove that a similar expression holds for the particle number fluctuations and use it to prove a two sided estimates on the entropy $S$.Comment: Final versio

Fact sheet: Assessing restoration objectives following a second-entry prescribed fire in an unharvested mixed conifer forest

Efforts to restore degraded forest ecosystems often involve thinning small-diameter trees and reintroducing surface fire; however, in some areas, such as national parks, mechanical tree thinning is kept to a minimum. In these situations, prescribed fire is the best tool available to restore historical fire regimes and forest structure over broad spatial scales

Preliminary results from the mineral ecosystem management area (EMA) experimental block study: One-year post-treatment. Special report to the Apache-Sitgreaves National Forests, USDA Forest Service, Region 3.

Southwestern ponderosa pine (Pinus ponderosa) forest ecosystems have become uncharacteristically dense as a result of livestock grazing, logging, and fire exclusion, which has led to an increase in vulnerability to high-severity, landscape-scale crown fires. In 2002, the Ecological Restoration Institute (ERI) at Northern Arizona University (NAU) and the Apache-Sitgreaves (A-S) National Forests cooperatively implemented a replicated ecological restoration experiment to (1) determine site-specific reference conditions, (2) measure and evaluate contemporary (pre-treatment) forest structure variables, and (3) test responses to three treatments: control, full restoration, and burn only. The site is located in a ponderosa pine forest and spans an elevation gradient from the pinyon-juniper ecotone to the dry mixed conifer ecotone. Reconstructed total basal area (BA) averaged 40 ft²/acre and total tree density averaged 35 trees/acre across all treatments indicating that a relatively open forest structure existed at the Mineral site in 1880. By 2002, prior to treatment, total BA had increased by more than 300% to an average of 125 ft²/acre and total tree density increased by more than 1000% to an average of 376 trees/acre. In 2009, following treatment, the full restoration treatment reduced total BA by 53% from 135 ft²/acre to 64 ft²/acre and total tree density by 83% from 404 trees/acre to 67 trees/acre. In the burn only treatment, total BA increased by 3% from 120 ft²/acre to 123 ft²/acre and tree density was reduced by 18% from 339 trees/acre to 279 trees/acre between 2002 and 2009. In the control, little change in total BA and tree density occurred between 2002 and 2009. Post-treatment diameter distributions in the full restoration treatment closely matched the historical distribution. In contrast, the burn only treatment had only small reductions in the lower diameter classes. Following treatment, about 15% of the presettlement trees died or were cut in the full restoration treatment compared to 23% mortality of presettlement trees in the burn only treatment. Ten percent of presettlement trees died in the control during the same time without active treatment. One year after application, the full restoration treatment shifted forest structure and diameter distributions within the range of variability historically present at the Mineral site. In contrast, the burn only treatment did not shift forest structure and diameter distributions within the historical range of variability in the short term. The ERI will conduct a five-year remeasurement at the Mineral site in the summer of 2013 and will build upon the information provided in this report to evaluate five-year post-treatment responses on forest structure, regeneration, surface fuels, canopy cover, herbaceous understory, and potential fire behavior