A rural agricultural-sustainable energy community model and its application to Felton Valley, Australia

Energy and food security require a delicate balance which should not threaten or undermine community prosperity. Where it is proposed to derive energy from conventional fossil fuel resources (such as coal, shale oil, natural gas, coal seam gas) located in established rural areas, and particularly where these areas are used for productive agricultural purposes, there are often both intense community concern as well as broader questions regarding the relative social, economic and environmental costs and benefits of different land uses and, increasingly, different energy sources. The advent of mainstream renewable energy technologies means that alternative energy options may provide a viable alternative, allowing energy demand to be met without compromising existing land uses. We demonstrate how such a Sustainable Energy Rural Model can be designed to achieve a balance between the competing social goals of energy supply, agricultural production, environmental integrity and social well-being, and apply it to the Felton Valley, a highly productive and resilient farming community in eastern Australia. Research into available wind and solar resources found that Felton Valley has a number of attributes that indicate its suitability for the development of an integrated renewable energy precinct which would complement, rather than displace, existing agricultural enterprises. Modelling results suggest a potential combined annual renewable energy output from integrated wind and solar resources of 1,287 GWh/yr from peak installed capacity of 713 MW, sufficient to supply the electrical energy needs of about 160,000 homes, in combination with total biomass food production of 31,000 tonnes per annum or 146 GWh/yr of human food energy. The portfolio of renewable energy options will not only provide energy source diversity but also ensures long-term food security and regional stability. The Felton Valley model provides an example of community-led energy transformation and has potential as a pilot project for the development of smart distributed grids that would negate the need for further expansion of coal mining and coal fired power stations

Recognition and repair of the cyclobutane thymine dimer, a major cause of skin cancers, by the human excision nuclease

The cyclobutane thymine dimer is the major DNA lesion induced in human skin by sunlight and is a primary cause of skin cancer, the most prevalent form of cancer in the Northern Hemisphere. In humans, the only known cellular repair mechanism for eliminating the dimer from DNA is nucleotide excision repair. Yet the mechanism by which the dimer is recognized and removed by this repair system is not known. Here we demonstrate that the six-factor human excision nuclease recognizes and removes the dimer at a rate consistent with the in vivo rate of removal of this lesion, even though none of the six factors alone is capable of efficiently discriminating the dimer from undamaged DNA. We propose a recognition mechanism by which the low-specificity recognition factors, RPA, XPA, and XPC, act in a cooperative manner to locate the lesion and, aided by the kinetic proofreading provided by TFIIH, form a high-specificity complex at the damage site that initiates removal of thymine dimers at a physiologically relevant rate and specificity

Emissions from Smoldering Combustion of Biomass Measured by Open-Path Fourier Transform Infrared Spectroscopy

Biomass samples from a diverse range of ecosystems were burned in the Intermountain Fire Sciences Laboratory open combustion facility. Midinfrared spectra of the nascent emissions were acquired at several heights above the fires with a Fourier transform infrared spectrometer (FTIR) coupled to an open multipass cell. In this report, the results from smoldering combustion during 24 fires are presented including production of carbon dioxide, carbon monoxide, methane, ethene, ethyne, propene, formaldehyde, 2-hydroxyethanal, methanol, phenol, acetic acid, formic acid, ammonia, hydrogen cyanide, and carbonyl sulfide. These were the dominant products observed, and many have significant influence on atmospheric chemistry at the local, regional, and global scale. Included in these results are the first optical, in situ measurements of smoke composition from fires in grasses, hardwoods, and organic soils. About one half of the detected organic emissions arose from fuel pyrolysis which produces white smoke rich in oxygenated organic compounds. These compounds deserve more attention in the assessment of fire impacts on the atmosphere. The compound 2-hydroxyethanal is a significant component of the smoke, and it is reported here for the first time as a product of fires. Most of the observed alkane and ammonia production accompanied visible glowing combustion. NH3 is normally the major nitrogen-containing emission detected from smoldering combustion of biomass, but from some smoldering organic soils, HCN was dominant. Tar condensed on cool surfaces below the fires accounting for ∼1% of the biomass burned, but it was enriched in N by a factor of 6–7 over the parent material, and its possible role in postfire nutrient cycling should be further investigated

Virtual discussions to support climate risk decision making on farms

Climate variability represents a significant risk to farming enterprises. Effective extension of climate information may improve climate risk decision making and adaptive management responses to climate variability on farms. This paper briefly reviews current agricultural extension approaches and reports stakeholder responses to new web-based virtual world ‘discussion-support’ tools developed for the Australian sugar cane farming industry. These tools incorporate current climate science and sugar industry better management practices, while leveraging the social-learning aspects of farming, to provide a stimulus for discussion and climate risk decision making. Responses suggest that such virtual world tools may provide effective support for climate risk decision making on Australian sugar cane farms. Increasing capacity to deliver such tools online also suggests potential to engage large numbers of farmers globally

Field measurements of trace gases emitted by prescribed fires in southeastern US pine forests using an open-path FTIR system

We report trace-gas emission factors from three pine-understory prescribed fires in South Carolina, US measured during the fall of 2011. The fires were more intense than many prescribed burns because the fuels included mature pine stands not subjected to prescribed fire in decades that were lit following an extended drought. Emission factors were measured with a fixed open-path Fourier transform infrared (OP-FTIR) system that was deployed on the fire control lines. We compare these emission factors to those measured with a roving, point sampling, land-based FTIR and an airborne FTIR deployed on the same fires. We also compare to emission factors measured by a similar OP-FTIR system deployed on savanna fires in Africa. The data suggest that the method used to sample smoke can strongly influence the relative abundance of the emissions that are observed. The majority of fire emissions were lofted in the convection column and were sampled by the airborne FTIR. The roving, ground-based, point sampling FTIR measured the contribution of individual residual smoldering combustion fuel elements scattered throughout the burn site. The OP-FTIR provided a ~ 30 m path-integrated sample of emissions transported to the fixed path via complex ground-level circulation. The OP-FTIR typically probed two distinct combustion regimes, "flaming-like" (immediately after adjacent ignition and before the adjacent plume achieved significant vertical development) and "smoldering-like." These two regimes are denoted "early" and "late", respectively. The path-integrated sample of the ground-level smoke layer adjacent to the fire from the OP-FTIR provided our best estimate of fire-line exposure to smoke for wildland fire personnel. We provide a table of estimated fire-line exposures for numerous known air toxics based on synthesizing results from several studies. Our data suggest that peak exposures are more likely to challenge permissible exposure limits for wildland fire personnel than shift-average (8 h) exposures

Gravitational-Wave Cosmology across 29 Decades in Frequency

Quantum fluctuations of the gravitational field in the early Universe, amplified by inflation, produce a primordial gravitational-wave background across a broad frequency band. We derive constraints on the spectrum of this gravitational radiation, and hence on theories of the early Universe, by combining experiments that cover 29 orders of magnitude in frequency. These include Planck observations of cosmic microwave background temperature and polarization power spectra and lensing, together with baryon acoustic oscillations and big bang nucleosynthesis measurements, as well as new pulsar timing array and ground-based interferometer limits. While individual experiments constrain the gravitational-wave energy density in specific frequency bands, the combination of experiments allows us to constrain cosmological parameters, including the inflationary spectral index nt and the tensor-to-scalar ratio r. Results from individual experiments include the most stringent nanohertz limit of the primordial background to date from the Parkes Pulsar Timing Array, ΩGW(f)\u3c2.3×10−10. Observations of the cosmic microwave background alone limit the gravitational-wave spectral index at 95% confidence to nt≲5 for a tensor-to-scalar ratio of r=0.11. However, the combination of all the above experiments limits nt\u3c0.36. Future Advanced LIGO observations are expected to further constrain nt\u3c0.34 by 2020. When cosmic microwave background experiments detect a nonzero r, our results will imply even more stringent constraints on nt and, hence, theories of the early Universe

Airborne and Ground-Based Measurements of the Trace Gases and Particles Emitted by Prescribed Fires in the United States

We have measured emission factors for 19 trace gas species and particulate matter (PM2.5) from 14 prescribed fires in chaparral and oak savanna in the southwestern US, as well as conifer forest understory in the southeastern US and Sierra Nevada mountains of California. These are likely the most extensive emission factor field measurements for temperate biomass burning to date and the only published emission factors for temperate oak savanna fuels. This study helps to close the gap in emissions data available for temperate zone fires relative to tropical biomass burning. We present the first field measurements of the biomass burning emissions of glycolaldehyde, a possible precursor for aqueous phase secondary organic aerosol formation. We also measured the emissions of phenol, another aqueous phase secondary organic aerosol precursor. Our data confirm previous observations that urban deposition can impact the NOx emission factors and thus subsequent plume chemistry. For two fires, we measured both the emissions in the convective smoke plume from our airborne platform and the unlofted residual smoldering combustion emissions with our ground-based platform. The smoke from residual smoldering combustion was characterized by emission factors for hydrocarbon and oxygenated organic species that were up to ten times higher than in the lofted plume, including high 1,3-butadiene and isoprene concentrations which were not observed in the lofted plume. This should be considered in modeling the air quality impacts for smoke that disperses at ground level. We also show that the often ignored unlofted emissions can significantly impact estimates of total emissions. Preliminary evidence suggests large emissions of monoterpenes in the residual smoldering smoke. These data should lead to an improved capacity to model the impacts of biomass burning in similar temperate ecosystems

Pulsar Scintillation through Thick and Thin: Bow Shocks, Bubbles, and the Broader Interstellar Medium

Observations of pulsar scintillation are among the few astrophysical probes of very small-scale ($\lesssim$ au) phenomena in the interstellar medium (ISM). In particular, characterization of scintillation arcs, including their curvature and intensity distributions, can be related to interstellar turbulence and potentially over-pressurized plasma in local ISM inhomogeneities, such as supernova remnants, HII regions, and bow shocks. Here we present a survey of eight pulsars conducted at the Five-hundred-meter Aperture Spherical Telescope (FAST), revealing a diverse range of scintillation arc characteristics at high sensitivity. These observations reveal more arcs than measured previously for our sample. At least nine arcs are observed toward B1929$+$10 at screen distances spanning $\sim 90\%$ of the pulsar's $361$ pc path-length to the observer. Four arcs are observed toward B0355$+$54, with one arc yielding a screen distance as close as $\sim10^5$ au ($<1$ pc) from either the pulsar or the observer. Several pulsars show highly truncated, low-curvature arcs that may be attributable to scattering near the pulsar. The scattering screen constraints are synthesized with continuum maps of the local ISM and other well-characterized pulsar scintillation arcs, yielding a three-dimensional view of the scattering media in context.Comment: 20 pages, 14 figures. Submitted to MNRAS and comments welcome. Interactive version of Figure 12 available at https://stella-ocker.github.io/scattering_ism3d_ocker202