Space and Time: Wind in an Investment Planning Model

Investment planning models inform investment decisions and government policies. Current models do not capture the intermittent nature of renewable energy sources, restricting the applicability of the models for high penetrations of renewables. We provide a methodology to capture spatial variation in wind output in combination with transmission constraints. The representation of wind distributions with stochastic approaches or an extensive historic data set would exceed computational constraints for real world application. Hence we restrict the amount of input data, and use boot-strapping to illustrate the robustness of the results. For the UK power system we model wind deployment and the value of transmission capacity

Assessing the vulnerability of the marine bird community in the western North Sea to climate change and other anthropogenic impacts

Ocean warming and anthropogenic activities such as fishing, shipping and marine renewable developments are affecting marine top predators. Research has focussed on the impacts of single stressors on single species, yet understanding cumulative effects of multiple stressors on communities is vital for effective conservation management. We studied a marine bird community (45 species; 11 families) that used the Forth and Tay region of the North Sea for breeding, overwintering or migration between 1980 and 2011. Local sea surface temperature (SST) increased significantly over this period, with concomitant changes in lower trophic levels. Simultaneously, the region has been subject to fishing pressure and shipping disturbance and is a priority area for renewable energy developments. We used colony-based and at-sea data to quantitatively assess relationships between SST and counts, productivity and survival of 25 species for which sufficient data were available for analysis. For the remaining species, we applied a qualitative approach using published population trends, published climate relationships and foraging sensitivity. In total, 53% of species showed negative relationships with SST. Trends in counts and demography were combined with climate vulnerability to give an index of population concern to future climate warming, and 44% of species were classified as high or very high concern, notably cormorants, grebes, skuas, shearwaters, terns and auks, as well as species breeding in the region. Qualitative assessments of vulnerability to fisheries, pollutants, disturbance (including introduced predators), marine renewables and climate found that 93% of species were vulnerable to ≥2 threats, and 58% to ≥4. Our results indicate that the majority of birds in this region of the North Sea face an uncertain future, potentially threatening the resilience of this important marine bird community

Deformation of an Elastic Beam on a Winkler Foundation

We present a simple model for geophysical systems involving sources of deformation, such as magmatic intrusions, supraglacial lakes, and the subsurface storage of CO 2 . We consider the idealised system of a uniform elastic layer overlying a localised region of constant pressure that is surrounded by a Winkler foundation composed of springs. We investigate the effect of source depth and foundation stiffness on the resulting displacement profiles at both the surface and the level of the source. The system is characterised by three key features: the maximum uplift, the maximum subsidence, and the distance to the point of zero displacement. For each of these we determine asymptotic scaling behaviour in the limits of a thin/thick layer and a soft/stiff foundation and form composite curves that allow specific parameter values to be determined from field data. Both two-dimensional and axisymmetric pressure patches are considered, and in the thin-layer limit we derive analytical solutions

Sublethal effects of natural parasitism act through maternal, but not paternal; reproductive success in a wild population

Parasites are a major component of all animal populations. Males and females often differ in their levels of parasite prevalence, potentially leading to sex differences in the impact of parasitism on fitness, with important implications for the evolution of parasite and host traits including resistance, tolerance, and virulence. However, quantitative measures of the impact of parasitism under free‐living conditions are extremely rare, as they require detailed host demographic data with measures of parasite burden over time. Here, we use endoscopy for direct quantification of natural‐parasite burdens and relate these to reproductive success over 7 yr in a wild population of seabirds. Contrary to predictions, only female burdens were associated with negative impacts of parasitism on breeding success, despite males having significantly higher burdens. Female reproductive success declined by 30% across the range of natural parasite burdens. These effects persisted when accounting for interannual population differences in breeding success. Our results provide quantitative estimates of profound sub‐lethal effects of parasitism on the population. Importantly, they highlight how parasites act unpredictably to shape ecological and evolutionary processes in different components of the same population, with implications for demography and selection on host and parasite traits

New specimens of the basal ornithischian dinosaur Lesothosaurus diagnosticus Galton, 1978 from the Early Jurassic of South Africa

We describe new specimens of the basal ornithischian dinosaur Lesothosaurus diagnosticus Galton, 1978 collected from a bone bed in the Fouriesburg district of the Free State, South Africa. The material was collected from the upper Elliot Formation (Early Jurassic) and represents the remains of at least three different individuals. These individuals are larger in body size than those already known in museum collections and offer additional information on cranial ontogeny in the taxon. Moreover, they are similar in size to the sympatric taxon Stormbergia dangershoeki. The discovery of three individuals at this locality might imply group-living behaviour in this early ornithischian

Improved Performance of Near infrared Excitation Raman Spectroscopy Using Reflective Thin-film Gold on Glass Substrates for Cytology Samples

Confocal near-infrared Raman spectroscopy has been shown to have applications in the area of clinical biology. A source wavelength in the near infrared is preferred over visible wavelengths for inspecting biological samples due to superior wave number resolution and reduced photo damage. However, these excitation sources have a number of drawbacks when compared to lasers in the visible wavelength region, including the requirement to use expensive highly pure crystal substrates such as Raman grade calcium fluoride as well as long acquisition times due to the lower Raman scattering efficiency. This paper investigates the use of a reflective substrate comprising a low cost 100 nm thin-film gold on glass substrate, as an alternative. Similar to recent work that used stainless steel substrates, it is demonstrated that the thin-film gold coated substrates, which are relatively inexpensive, produce cell spectra with 1.65 times the signal to noise ratio when compared with spectra obtained from calcium fluoride under identical conditions, with no apparent background signal in the fingerprint region. Two prostate cell lines are examined having been deposited on glass, calcium fluoride, and thin-film gold on glass substrates using the Thin Prep standard. Background spectra from, and cell adhesion on, these three substrates are compared. A comparison of the intensities and signal to noise ratios of the resulting spectra, and their viability for classification using principle components analysis is performed, which further demonstrates the benefit of reflective substrates

The energetic cost of parasitism in a wild population

Parasites have profound fitness effects on their hosts, yet these are often sub-lethal, making them difficult to understand and quantify. A principal sub-lethal mechanism that reduces fitness is parasite-induced increase in energetic costs of specific behaviours, potentially resulting in changes to time and energy budgets. However, quantifying the influence of parasites on these costs has not been undertaken in free-living animals. We used accelerometers to estimate energy expenditure on flying, diving and resting, in relation to a natural gradient of endo-parasite loads in a wild population of European shags Phalacrocorax aristotelis. We found that flight costs were 10% higher in adult females with higher parasite loads and these individuals spent 44% less time flying than females with lower parasite loads. There was no evidence for an effect of parasite load on daily energy expenditure, suggesting the existence of an energy ceiling, with the increase in cost of flight compensated for by a reduction in flight duration. These behaviour specific costs of parasitism will have knock-on effects on reproductive success, if constraints on foraging behaviour detrimentally affect provisioning of young. The findings emphasize the importance of natural parasite loads in shaping the ecology and life-history of their hosts, which can have significant population level consequences

Protracted treatment with corticosterone reduces breeding success in a long-lived bird

Determining the physiological mechanisms underpinning life-history decisions is essential for understanding the constraints under which life-history strategies can evolve. In long-lived species, where the residual reproductive value of breeders is high, adult survival is a key contributor to lifetime reproductive success. We therefore expect that when adult survival is compromised during reproduction, mechanisms will evolve to redirect resources away from reproduction, with implications for reproductive hormones, adult body mass, nest attendance behaviour and breeding success. We investigated whether manipulating corticosterone, to simulate exposure to an environmental stressor, affected the secretion of prolactin and breeding success in the black-legged kittiwake Rissa tridactyla. We used implanted Alzet® osmotic pumps to administer corticosterone to incubating kittiwakes at a constant rate over a period of approximately eight days. Manipulated birds were compared with sham implanted birds and control birds, which had no implants. There was no significant difference in the body mass of captured individuals at the time of implantation and implant removal. Corticosterone-implanted males showed lower nest attendance during the chick rearing period compared to sham-implanted males; the opposite pattern was found in females. Corticosterone treated birds showed a marginally significant reduction in breeding success compared to sham-implanted individuals, with all failures occurring at least one week after implant removal. However, prolactin concentrations at implant removal were not significantly different from initial values. We were unable to measure the profile of change in corticosterone during the experiment. However, our results suggest a delayed effect of elevated corticosterone on breeding success rather than an immediate suppression of prolactin concentrations causing premature failure

Isotopic Composition of the Ogallala-high Plains Aquifer Andvadose Zone

AbstractThe Ogallala-High Plains aquifer is an important resource for irrigated agriculture in a semi-arid region of the United States. Steep declines in groundwater levels are putting increasing strain on the viability of the aquifer for irrigation, necessitating improved estimates of recharge rates and sources to the aquifer. This study uses a combined approach to obtain high resolution geochemical and isotopic composition of the vadose zone and aquifer pore fluids to better understand recharge dynamics to the aquifer. Significant differences between the shallow, intermediate and deep vadose zone and shallow and deep aquifer indicate modern precipitation is not providing a significant source of recharge to the aquifer across a large area (diffuse recharge). Rather, recharge to the aquifer is a result of either focused recharge or long-term, delayed drainage from the portion of the vadose zone which was saturated before irrigation development

Porosity detection in electron beam-melted Ti-6Al-4V using high-resolution neutron imaging and grating-based interferometry

© 2017, Springer International Publishing Switzerland. A high-resolution neutron tomography system and a grating-based interferometer are used to explore electron beam-melted titanium test objects. The high-resolution neutron tomography system (attenuation-based imaging) has a pixel size of 6.4 µm, appropriate for detecting voids near 25 µm over a (1.5 cm)3 volume. The neutron interferometer provides dark-field (small-angle scattering) images with a pixel size of 30 µm. Moreover, the interferometer can be tuned to a scattering length, in this case, 1.97 µm, with a field-of-view of (6 cm)3. The combination of high-resolution imaging with grating-based interferometry provides a way for nondestructive testing of defective titanium samples. A chimney-like pore structure was discovered in the attenuation and dark-field images along one face of an electron beam-melted (EBM) Ti-6Al-4V cube. Tomographic reconstructions of the titanium samples are utilized as a source for a binary volume and for skeletonization of the pores. The dark-field volume shows features with dimensions near and smaller than the interferometer auto-correlation scattering length