Showing papers by "James Taylor published in 2021"

Hierarchical Probabilistic Forecasting of Electricity Demand With Smart Meter Data

Abstract: Decisions regarding the supply of electricity across a power grid must take into consideration the inherent uncertainty in demand. Optimal decision-making requires probabilistic forecasts for deman...

Precision agriculture technology adoption: a qualitative study of small-scale commercial “family farms” located in the North China Plain

Abstract: Precision agriculture (PA) technologies offer a potential solution to food security and environmental challenges but, will only be successful if adopted by farmers. Adoption in China lags behind that in some developed agricultural economies despite scientifically proven benefits of PA technologies for Chinese agriculture. Adoption is dependent on farmer attitudes and perceptions towards PA technologies. An exploratory qualitative study using in-depth interviews was conducted with Chinese arable farmers (n = 27) to explore their perceptions towards and adoption intentions of PA technologies in two Chinese provinces (Hebei and Shandong). A thematic analysis revealed five central themes to have emerged from the data, these were: “socio-political landscape”, “farming culture”, “agricultural challenges”, “adoption intentions (barriers/facilitators” and “practical support mechanisms” . All were likely to influence the level and rate of adoption of PA technologies amongst family farmers in China. The research revealed an openness to the potential of PA technologies amongst family farmers, although there was heterogeneity in the perceptions of PA technology and willingness to adopt. Improved rates of adoption will be achieved by reducing the barriers to adoption, including the need for low-cost PA applications that can be applied at small scale, improved information provision, financial support mechanisms including more accessible subsidies and credit, and reliable, regulated and affordable service provision.

Seeded optical parametric generation in CdSiP2 pumped by a Raman fiber amplifier at 124 µm

Abstract: We report a seeded optical parametric generator (OPG) producing tunable radiation from 42–46 µm The seeded OPG employs a 13 mm long CdSiP2 (CSP) crystal cut for non-critical phase-matching, pumped by a nanosecond-pulsed, MHz repetition rate Raman fiber amplifier system at 124 µm A filtered, continuous-wave fiber supercontinuum source at 172 µm is used as the seed The source generates up to 025 W of mid-infrared (MIR) idler power with a total pump conversion of 42% (combined signal and idler)

ApeX-Vigne: experiences in monitoring vine water status from within-field to regional scales using crowdsourcing data from a free mobile phone application

Abstract: Monitoring vine water status is a major issue for vineyard management because water constraints impact both the quality and the quantity of the harvest. Existing methods are often costly and complex to implement. ApeX-Vigne is a free mobile application developed to facilitate the collection and geolocation of 50 vine apex observations to characterise vine shoot growth and classify it into 3 growth categories. The application also provides the user with a simple estimate of vine water status based on shoot growth. This paper presents the results obtained over two seasons (2019 and 2020) after the launch of the Apex-Vigne application and its use over a large wine producing region in the south of France. An existing method was adapted for evaluating the interest of the application based on the number of installations and uninstallations. The results showed that the application had more than 1200 downloads and 6000 observations made in the 2020 season. Examples from the commercially collected data showed that ApeX-Vigne can be used as a tool for characterizing water stress at within-field and inter-field scales. Finally, it was also demonstrated that by enabling the massive and centralized collection of spatial field and within-field scale observations of shoot growth, the ApeX-Vigne data was able to characterise the spatial structure of vine water status at the regional scale. Access to this new source of information offers opportunities for the management of water resources at a regional scale as well as for site- and vineyard-specific management. These results also raised new research questions on the joint use of this new source of spatial data with other sources of high spatial resolution information.

The discovery and preliminary geological and faunal descriptions of three new Steinahóll vent sites, Reykjanes Ridge, Iceland

Abstract: During RV MS Merian expedition MSM75, an international, multidisciplinary team explored the Reykjanes Ridge from June to August 2018. The first area of study, Steinaholl (150–350 m depth), was chosen based on previous seismic data indicating hydrothermal activity. The sampling strategy included ship- and AUV-mounted multibeam surveys, Remotely Operated Vehicle (ROV), Epibenthic Sledge (EBS), and van Veen grab (vV) deployments. Upon returning to Steinaholl during the final days of MSM75, hydrothermal vent sites were discovered using the ROV Phoca (Kiel, GEOMAR). Here we describe and name three new, distinct hydrothermal vent site vulnerable marine ecosystems (VMEs); Hafgufa, Stokkull, Lyngbakr. The hydrothermal vent sites consisted of multiple anhydrite chimneys with large quantities of bacterial mats visible. The largest of the three sites (Hafgufa) was mapped, and reconstructed in 3D. In total 23,310 individual biological specimens were sampled comprising 41 higher taxa. Unique fauna located in the hydrothermally venting areas included two putative new species of harpacticoid copepod (Tisbe sp. nov. and Amphiascus sp. nov.), as well as the sponge Lycopodina cupressiformis (Carter, 1874). Capitellidae Grube, 1862 and Dorvilleidae Chamberlin, 1919 families dominated hydrothermally influenced samples for polychaetes. Around the hydrothermally influenced sites we observed a notable lack of megafauna, with only a few species being present. While we observed hydrothermal associations, the overall species composition is very similar to that seen at other shallow water vent sites in the north of Iceland, such as the Mohns Ridge vent fields, particularly with peracarid crustaceans. We therefore conclude the community overall reflects the usual “background” fauna of Iceland rather than consisting of “vent endemic” communities as is observed in deeper vent systems, with a few opportunistic species capable of utilizing this specialist environment.

Watt-level 743 nm source by second-harmonic generation of a cascaded phosphosilicate Raman fiber amplifier

Abstract: We demonstrate a nanosecond pulsed 743 nm source through second-harmonic generation of a cascaded phosphosilicate Raman fiber amplifier system operating at 1485 nm. The amplifier is pumped by a 1240 nm phosphosilicate Raman fiber amplifier and seeded with a continuous-wave 1485 nm diode. This 1485 nm light is used for second-harmonic generation in periodically poled lithium niobate. Greater than 1 W of average power is generated at 743 nm with a corresponding pulse energy of 220 nJ at a repetition rate of 5 MHz. The source displays excellent beam quality (M x,y2 ≤ 1.18) with ideal parameters for biomedical imaging applications.

Evaluation of the Concord Crop Load Response for Current Commercial Production in New York

Abstract: Economic pressures in the New York Concord grape industry over the past 30 years have driven crop management practices toward less severe pruning to achieve larger crops. The purpose of this study was to investigate the effect of crop load on juice soluble solids and the seasonal change in vine pruning weight in New York Concord grapevines. Over a four-year period, vines were balanced pruned at two levels or fixed node pruned at two levels to give four pruning severities. For balanced pruning, vines were pruned to leave 33 or 66 fruiting nodes for the first 500 g pruning weight and an additional 11 nodes for each additional 500 g pruning weight. For fixed node pruning, vines were pruned to 100 or 120 fruiting nodes per vine. The 120-node vines were also manually cluster-thinned at 30 days after bloom to target 0, 25, or 50% crop removal. In a second study, the 120-node pruning with midseason fruit-thinning was repeated over 11 years to assess seasonal differences on the crop load response. Crop load was measured as the yield-to-pruning weight ratio (Y:PW) and ranged from 1 to 40 in this study. On average, the industry standard of 16 Brix was achieved at a Y:PW of 20, and no seasonal pruning weight change was observed at a Y:PW of 17.5. There was a positive linear relationship between seasonal growing degree days and the Y:PW needed to reach 16 Brix, as well as between seasonal precipitation and the Y:PW required to observe no seasonal pruning weight change. The results from this study were used to improve crop load management recommendations for New York Concord vineyards under current practices.

Evaluating the drivers of banana flowering cycle duration using a stochastic model and on farm production data

Abstract: The use of data produced by farmers to generate knowledge and to inform production decisions is one of the objectives of precision agriculture (PA). Frameworks to analyse and represent those data are now widely available for many crops but are not relevant to banana cropping systems because of its asynchronicity. The average period between two flowering events on the same plant, called CD, is variable, as opposed to most crops whose phenology is synchronized by the seasons. Therefore, CD is a property of interest for understanding yields but it cannot be easily measured in plantations. In this study, a method was proposed to generate information on CD using the producer’s commercially collected production data on flowering from 724 fields over 15 years in a Cameroonian plantation. A new stochastic model based on the development of the banana plant and using CD as a parameter was formulated. This model was then adjusted using temporal flowering data to estimate CD at the field level. Results showed that CD was variable between fields (median of 209 days and standard deviation of 24 days) and spatially structured (autocorrelation ratio of 0.87). The effect of management (irrigation, cultivar) and environmental conditions (temperatures, elevation) on CD was studied. There was no positive effect of thermal time (degree days) vs. Julian days on model fitting and the CD estimation. In contrast, elevation, cultivar and irrigation had an effect on CD. For growers, this highlights the importance of taking into account CD when analysing yields, and not to rely only on the weight of the bunches at harvest. It also shows that production data can be effectively used and mapped to inform production decisions.

Comparison of Different Vegetative Indices for Calibrating Proximal Canopy Sensors to Grapevine Pruning Weight

Abstract: Canopy sensing in viticulture is widely associated with the term NDVI (normalized difference vegetation index). However, there are many other vegetative indices (VIs) that can be calculated from information captured with visible/near-infrared (NIR) sensors. A proximal canopy sensor was used to survey 27 vineyards in the Lake Erie Concord belt and stratified to collect pruning weights (PW) at a density of ~25 samples per vineyard. Seven VIs were derived from the sensor data and the first principal component (PC1) extracted from a principal components analysis of the seven VIs. The VIs and PC1 were regressed against the local PW measurements and ranked in terms of their goodness-of-fit. Over the 27 vineyards, there was no single VI that outperformed the others, although VIs that used the red-edge band had a slight advantage over VIs using the red band. It is therefore recommended to use the normalized difference red edge index (NDRE) in place of the NDVI when predicting PW from terrestrial-based proximal canopy surveys. The PC1 derived from the decomposition of all seven VIs did appear to convey some benefit to PW prediction compared with a single VI approach, particularly with just NDVI. More research into the potential for multivariate approaches is recommended.

The influence of smoking on the pattern of disability and relapse risk in AQP4-positive Neuromyelitis Optica Spectrum Disorder, MOG-Ab Disease and Multiple Sclerosis.

Abstract: Background: the role of smoking on clinical outcomes of central nervous system (CNS) inflammatory disorders is unclear. To assess the effect of smoking on relapses and disability in neuromyelitis optica with aquaporin-4-antibodies (NMOSD-AQP4-Ab), Myelin Oligodendrocyte Glycoprotein-antibodies associated disease (MOGAD) and relapsing remitting Multiple Sclerosis (MS) patients. Methods: in a UK cohort of 101 NMOSD-AQP4-Ab, 70 MOGAD and 159 MS, and a Korean cohort of 97 NMOSD-AQ4-Ab, time to first relapse, annualised relapse rate, onset relapse severity and recovery, time to Expanded Disability Status Score(EDSS)/secondary progressive MS (SPMS) were compared between never-smokers and ever-smokers. All clinical data were collected under the local ethics between January 2017 and January 2019. Results: Smoking did not affect the risk of relapse in any of the diseases. The risk of reaching EDSS 6.0 in the UK NMOSD-AQP4-Ab cohort was higher in ever smokers but this did not achieve significance (HR 2.12, p=0.068). When combining the UK and Korea NMOSD-AQP4-Ab cohorts, poorer recovery from the onset attack was significantly more frequent in the ever-smokers versus the never smokers (55% vs 38%, p=0.04). In the MS cohort the risk of reaching EDSS 6 and SPMS was significantly higher in the ever-smokers (HR=2.67, p=0.01 and HR=3.18, p=0.001). In MOGAD similar patterns were seen without reaching significance. Conclusions: In NMOSD-AQP4-Ab smoking associates with worse disability not through an increased risk of relapses but through poor relapse recovery. As in MS, smoking cessation should be encouraged in NMOSD-AQP4-Ab.

Skeuomorphism in digital archaeological practice : A barrier to progress, or a vital cog in the wheels of change?

Abstract: Drawing upon the author’s combined experiences of developing digital field workflows at the sites of Catalhoyuk in Turkey and Kampinge in Sweden, this paper will discuss the role of skeuomorphism within the context of digital archaeological practice, and specifically, it will focus upon the ways that the use of digital technology affects the epistemological processes associated with fieldwork. In doing so it will examine whether common trends towards skeuomorphism in digital structure and practice may actually form an essential part of the process of ‘getting to grips’ with new digital technologies and shape a conceptual framework for this process. This framework will be discussed within the context of wider disciplinary trends and theory and ultimately a case will me made that skeuomorphism may need to be embraced if, as a discipline, we are going to explore the potential of emergent digital technologies to transform our digital practice in the long term (Less)

Brillouin-like amplification in rare-earth-doped optical fibers.

Abstract: We present a theoretical formalism to describe the amplification of two monochromatic waves counter-propagating in a rare-earth-doped optical fiber amplifier. Interaction of the waves through a dynamical population inversion grating inscribed in the active fiber by the waves during their amplification results in a strong power transfer from one wave to another providing a preferable amplification of one wave at the expense of another. In this sense, the effect is similar to stimulated Brillouin scattering and is expected to be observed with both pumped and unpumped rare-earth-doped fibers possessing a finite polarizability difference between the excited and ground states.

Real representations of C2-graded groups : the linear and Hermitian theories

Abstract: We study linear and hermitian representations of finite C2-graded groups. We prove that the category of linear representations is equivalent to a category of antilinear representations as an infinity-category. We also prove that the category hermitian representations, as an ∞-category, is equivalent to a category of usual representations.

Harnessing the Wisdom of the Crowd to Forecast Incident and Cumulative COVID-19 Mortality in the United States

Abstract: Background Forecasting models have played a pivotal role in health policy decision making during the coronavirus disease-2019 (COVID-19) pandemic. A combined forecast from multiple models will be typically more accurate than an individual forecast, but there are few examples of studies of combined forecasts of COVID-19 data, focusing mainly on simple mean and median ‘ensembles’ and involving short forecast evaluation periods. We aimed to investigate the accuracy of different ways of combining probabilistic forecasts of weekly COVID-19 mortality data, including two weighted methods that we developed previously, on an extended dataset and new dataset, and evaluate over a period of 52 weeks. Methods We considered 95% interval and point forecasts of weekly incident and cumulative COVID-19 mortalities between 16 May 2020 and 8 May 2021 in multiple locations in the United States. We compared the accuracy of simple and more complex combining methods, as well as individual models. Results The average of the forecasts from the individual models was consistently more accurate than the average performance of these models (the mean combination), which provides a fundamental motivation for combining. Weighted combining performed well for both incident and cumulative mortalities, and for both interval and point forecasting. Our inverse score with tuning method was the most accurate overall. The median combination was a leading method in the last quarter for both mortalities, and it was consistently more accurate than the mean combination for point forecasting. For interval forecasts of cumulative mortality, the mean performed better than the median. The best performance of the leading individual model was in point forecasting. Conclusions Combining forecasts can improve the contribution of probabilistic forecasting to health policy decision making during epidemics, and, when there are sufficient historical data on forecast accuracy, weighted combining provides the most accurate method.

Seeded optical parametric generation in CdSiP2 pumped by a nanosecond pulsed, MHz repetition rate Raman fiber amplifier at 1.24 µm

Abstract: We report a CdSiP2 (CSP) based seeded optical parametric generator (OPG), emitting sub-nanosecond duration, 3 MHz repetition rate, wavelength tunable mid-infrared (MIR) light at 4.2-4.6 μm. We generate up to 0.25 W at 4.2 μm with a total pump conversion efficiency of 42%. The OPG is pumped by a 1.24 μm Raman fiber amplifier system. This is the first demonstration of pumping CSP with a Raman fiber source in this region, and we show that Raman fiber sources in the near-infrared (NIR) are ideal pump sources for non-critically phasematched (NCPM) CSP devices. Pumping CSP at 1.24 μm permits the use of NCPM whilst decreasing the negative effects of both two-photon absorption and linear absorption losses, when compared to conventional 1 μm pumping. This offers a potential advantage for MIR power scaling of CSP parametric devices due to a reduced thermal load in the crystal from residual pump absorption. The OPG is seeded with a continuous-wave fiber supercontinuum source emitting radiation in the 1.7 μm region, to lower the threshold pump intensity required for efficient conversion. NCPM and temperature tuning of the crystal allow for simple wavelength tuning of the idler radiation. We report on laser damage induced by elevated crystal temperatures, which we propose is linked to the decrease in CSP bandgap energy with increasing temperature.

The Picard Group of Vertex Affinoids in the First Drinfeld Cover

Abstract: Let $F$ be a finite extension of $\mathbb{Q}_p$. Let $\Omega$ be the Drinfeld upper half plane, and $\Sigma^1$ the first Drinfeld cover of $\Omega$. We study the affinoid open subset $\Sigma^1_v$ of $\Sigma^1$ above a vertex of the Bruhat-Tits tree for $\text{GL}_2(F)$. Our main result is that $\text{Pic}(\Sigma^1_v)[p] = 0$, and using this we can describe the representation $H^1_{\text{\'{e}t}}(\Sigma^1_v, \mathbb{Z}_p(1))$ of $\text{GL}_2(\mathcal{O}_F)$ as the $p$-adic completion of $\mathcal{O}(\Sigma^1_v)^\times$. We also consider the Deligne-Lustig variety $\mathbf{Y}$ for $\text{SL}_2(\mathbb{F}_q)$, and we prove that $\text{Pic}(\mathbf{Y})[p] = 0$.