Evaluating the social and environmental factors behind the 2015 extreme fire event in Sumatra, Indonesia

Fires in Indonesia release excessive carbon and are exacerbated during drier El Niño years. The recent 2015 fires were affected by an extended drought caused by a strong El Niño event. This led to severe haze conditions across Southeast Asia, resulting in adverse socioeconomic and health impacts. Here, we evaluate the social and environmental factors that contributed to the 2015 extreme fires in Riau, Jambi and South Sumatra. We developed proxy variables for plausible drivers of fire which contribute either as a predisposing condition or as an ignition source for fires. We evaluated how these variables influenced fire count at an administrative regency-level and fire occurrence at a pixel-level (1 km2). We used generalized linear mixed effect models to model fire count at the regency-level and boosted regression trees to model fire occurrence at the pixel-level. Rainfall, slope and population density were the most important variables predicting fires at both levels. Economic variables such as the proportion of small-scale (<10 ha) and medium-scale (10–100 ha) plantation landholdings, and the reported use of fires to clear agricultural lands in villages were important in explaining fire count at the regency-level. At the pixel-level, distance from roads and the number of recorded burns over peatlands were important in explaining fire occurrence. The main influence of rain on fires corroborates with previous studies, and highlights the importance of establishing an early warning system for droughts to better prevent and manage future extreme fire events. Mitigation efforts for future fires, especially during El Niño years, can focus on identifying high-risk areas using environmental data on rainfall, slope, peatlands, and previously burnt peat areas, as well as social data related to population density, access to roads, extents of small- and medium-plantation landholdings, and village-level propensity to burn land for agriculture

Al0.52In0.48P avalanche photodiodes for soft X-ray spectroscopy

The performance of Al0.52In0.48P avalanche photodiodes was assessed as soft X-ray detectors at room temperature. The effect of the avalanche gain improved the energy resolution and an energy resolution (FWHM) of 682 eV is reported for 5.9 keV X-rays

Indigenous Peoples' lands are critical for safeguarding vertebrate diversity across the tropics

Indigenous Peoples are long-term custodians of their lands, but only recently are their contributions to conservation starting to be recognized in biodiversity policy and practice. Tropical forest loss and degradation are lower in Indigenous lands than unprotected areas, yet the role of Indigenous Peoples' Lands (IPL) in biodiversity conservation has not been properly assessed from regional to global scales. Using species distribution ranges of 11,872 tropical forest-dependent vertebrates to create area of habitat maps, we identified the overlap of these species ranges with IPL and then compared values inside and outside of IPL for species richness, extinction vulnerability, and range-size rarity. Of assessed vertebrates, at least 76.8% had range overlaps with IPL, on average overlapping ~25% of their ranges; at least 120 species were found only within IPL. Species richness within IPL was highest in South America, while IPL in Southeast Asia had highest extinction vulnerability, and IPL in Dominica and New Caledonia were important for range-size rarity. Most countries in the Americas had higher species richness within IPL than outside, whereas most countries in Asia had lower extinction vulnerability scores inside IPL and more countries in Africa and Asia had slightly higher range-size rarity in IPL. Our findings suggest that IPL provide critical support for tropical forest-dependent vertebrates, highlighting the need for greater inclusion of Indigenous Peoples in conservation target-setting and program implementation, and stronger upholding of Indigenous Peoples' rights in conservation policy

A global conservation basic income to safeguard biodiversity

Biodiversity conservation supporting a global sustainability transformation must be inclusive, equitable, just and embrace plural values. The conservation basic income (CBI), a proposed unconditional cash transfer to individuals residing in important conservation areas, is a potentially powerful mechanism for facilitating this radical shift in conservation. This analysis provides comprehensive projections for potential gross costs of global CBI using spatial analyses of three plausible future conservation scenarios. Gross costs vary widely, depending on the areas and populations included, from US$351 billion to US$6.73 trillion annually. A US$5.50 per day CBI in existing protected areas in low- and middle-income countries would cost US$478 billion annually. These costs are large compared with current government conservation spending (~US$133 billion in 2020) but represent a potentially sensible investment in safeguarding incalculable social and natural values and the estimated US$44 trillion in global economic production dependent on nature

Characterization of gallium arsenide X-ray mesa p-i-n photodiodes at room temperature

Two GaAs mesa p+-i-n+ photodiodes intended for photon counting X-ray spectroscopy, having an i layer thickness of 7 μm and diameter of 200 μm, have been characterized electrically, for their responsivity at the wavelength range 580 nm to 980 nm and one of them for its performance at detection of soft X-rays, at room temperature. Dark current and capacitance measurements as a function of applied forward and reverse bias are presented. The results show low leakage current densities, in the range of nA/cm2 at the maximum internal electric field (22 kV/cm). The unintentional doping concentration of the i layer, calculated from capacitance measurements, was found to be <1014 cm−3. Photocurrent measurements were performed under visible and near infrared light illumination for both diodes. The analysis of these measurements suggests the presence of a non-active (dead) layer (0.16 μm thickness) at the p+ side top contact interface, where the photogenerated carriers do not contribute to the photocurrent, possibly due to recombination. One of the diodes, D1, was also characterized as detector for room temperature photon counting X-ray spectroscopy; the best energy resolution achieved (FWHM) at 5.9 keV was 745 eV. The noise analysis of the system, based on spectra obtained at different shaping times and applied reverse biases, showed that the dominant source of noise is the dielectric noise. It was also calculated that there was at least (165±24) eV charge trapping noise at 0 V

Multi-dimensional modeling and simulation of semiconductor nanophotonic devices

Self-consistent modeling and multi-dimensional simulation of semiconductor nanophotonic devices is an important tool in the development of future integrated light sources and quantum devices. Simulations can guide important technological decisions by revealing performance bottlenecks in new device concepts, contribute to their understanding and help to theoretically explore their optimization potential. The efficient implementation of multi-dimensional numerical simulations for computer-aided design tasks requires sophisticated numerical methods and modeling techniques. We review recent advances in device-scale modeling of quantum dot based single-photon sources and laser diodes by self-consistently coupling the optical Maxwell equations with semiclassical carrier transport models using semi-classical and fully quantum mechanical descriptions of the optically active region, respectively. For the simulation of realistic devices with complex, multi-dimensional geometries, we have developed a novel hp-adaptive finite element approach for the optical Maxwell equations, using mixed meshes adapted to the multi-scale properties of the photonic structures. For electrically driven devices, we introduced novel discretization and parameter-embedding techniques to solve the drift-diffusion system for strongly degenerate semiconductors at cryogenic temperature. Our methodical advances are demonstrated on various applications, including vertical-cavity surface-emitting lasers, grating couplers and single-photon sources

Reduced deforestation and degradation in Indigenous Lands pan-tropically

Area-based protection is the cornerstone of international conservation policy. The contribution of Indigenous Lands (ILs)—areas traditionally owned, managed, used or occupied by Indigenous Peoples—is increasingly viewed as critical in delivering on international goals. A key question is whether deforestation and degradation are reduced on ILs pan-tropically and their effectiveness relative to Protected Areas (PAs). We estimate deforestation and degradation rates from 2010 to 2018 across 3.4 million km2 (Mkm2) ILs, 2 Mkm2 of PAs and 1.7 Mkm2 of overlapped Protected Indigenous Areas (PIAs) relative to matched counterfactual non-protected areas. Deforestation is reduced in ILs relative to non-protected areas across the tropics, avoiding deforestation comparably to PAs and PIAs except in Africa, where they avoid more. Similarly, degradation is reduced in ILs relative to non-protected areas, broadly performing comparably to PAs and PIAs. Indigenous support is central to forest conservation plans, underscoring the need for conservation to support their rights and recognize their contributions