60 research outputs found

    M87: A Misaligned BL LAC?

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    The nuclear region of M87 was observed with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope (HST) at 6 epochs, spanning 18 months, after the HST image quality was improved with the deployment of the corrective optics (COSTAR) in December 1993. From the FOS target acquisition data, we have established that the flux from the optical nucleus of M87 varies by a factor ~2 on time scales of ~2.5 months and by as much as 25% over 3 weeks, and remains unchanged (<= 2.5%) on time scales of ~1 day. The changes occur in an unresolved central region <= 5 pc in diameter, with the physical size of the emitting region limited by the observed time scales to a few hundred gravitational radii. The featureless continuum spectrum becomes bluer as it brightens while emission lines remain unchanged. This variability combined with the observations of the continuum spectral shape, strong relativistic boosting and the detection of significant superluminal motions in the jet, strongly suggest that M87 belongs to the class of BL Lac objects but is viewed at an angle too large to reveal the classical BL Lac properties.Comment: 12 pages, 3 Postscript figure

    Mid-IR Observations of T Tauri stars: Probing the Star-Disk Connection in Rotational Evolution

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    We present mid-IR N-band (\lambda_{eff} = 10.2\micron) photometry of a carefully selected sample of T Tauri stars thought to be single from the Taurus-Auriga molecular cloud. Infrared excesses in these stars are generally attributed to circumstellar dust-disks. Combining observations at 2.16\micron (Ks_{s}-band) and 10.2\micron (N-band) we probe a region in the circumstellar dust-disk from a few stellar radii through the terrestrial planet zone (0.02-1.0AU). By analyzing the distribution of the (KsN)(K_{s}-N) color index with respect to previously measured photometric rotation periods we investigate what role circumstellar disks play in the rotational evolution of the central star. The resulting positive correlation between these two variables is consistent with the notion that a star-disk interaction facilitates the regulation of angular momentum during the T Tauri stage. We also demonstrate, how including non-single stars in such an analysis will \textit{weaken} any correlation in the relation between (KsN)(K_{s}-N) color and period. To further understand disk properties we also present SEDs for a few objects with new ground based M-band (\lambda_{eff} = 4.8\micron) and Q-band (\lambda_{eff} = 20\micron) data and compare them to a geometrically thin, optically-thick disk model.Comment: 9 pages, 4 figure

    Methodology for Quantifying the Impact of Repurposing Existing Manufacturing Facilities: Case Study Using Pulp and Paper Facilities for Sustainable Aviation Fuel Production

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    13-C-AJFF-WaSU-013This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) license https://creativecommons.org/licenses/by/4.0/. Please cite this article as: Brandt, K., Camenzind, D., Zhu, J.Y., Latta, G., Gao, J. and Wolcott, M. (2022), Methodology for quantifying the impact of repurposing existing manufacturing facilities: case study using pulp and paper facilities for sustainable aviation fuel production. Biofuels, Bioprod. Bioref., 16: 1227-1239. https://doi.org/10.1002/bbb.2369Sustainable aviation fuel (SAF) is vital for the reduction of the environmental impact of the aviation industry while decreasing the dependence of the USA on foreign petroleum fuels. To date, SAF, especially from cellulosic feedstocks, have struggled to overcome two barriers: (1) meeting price parity with their petroleum counterparts and (2) the large capital investment required for industrial-scale biorefineries. Repurposing of industrial facilities has been suggested as a means of addressing both challenges. In this study we look at the financial impact of manufacturing SAF using three repurposing value levels. To demonstrate the application of this methodology, we examine case studies based on a wood-based alcohol-to-jet process. Each level evaluated assumes a different portion of the existing facility is useable. The impact on capital costs and minimum fuel selling price is estimated for generalized case studies as well as for specific case studies spread across multiple regions of the USA. The best economic outcomes are achieved when large-scale facilities have both inside and outside battery limit assets that can be repurposed. The geospatially explicit variables that have the largest economic impact are feedstock price, feedstock composition, and industrial natural gas price. However, the scale and value of repurposing both outweigh the geospatial variables within reasonable limits. Of the locations studied, the lowest minimum selling price (MSP) of $1.16/L was calculated at the Washington facility, a nearly 19% reduction from a matching scaled greenfield facility, a result of existing equipment and infrastructure reducing total capital investment by one-third and plentiful feedstock

    Multi-Component Resilience Assessment Framework for a Supply Chain System

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    13-C-AJFE-WaSU-016This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) license https://creativecommons.org/licenses/by/4.0/. Please cite this article as: Zhao, J.; Lee, J.Y.; Camenzind, D.;Wolcott, M.; Lewis, K.; Gillham, O. Multi-Component Resilience Assessment Framework for a Supply Chain System. Sustainability 2023, 15, 6197. https://doi.org/10.3390/su15076197The goal of this paper is to develop a quantitative resilience assessment framework for a supply chain system exposed to multiple risk factors. Most existing studies on supply chain resilience have primarily focused on assessing the system\u2019s ability to withstand and recover from disruptions caused by a single type of hazard. However, a supply chain system is exposed to multiple exogenous and endogenous events and conditions over a planning horizon, and a comprehensive assessment of resilience should take into account multiple risk factors. Moreover, contrary to the conventional resilience assessment methods focusing on the short duration during which the system is impacted by a disaster event, the proposed framework measures the resilience capacities of the system over a long-term horizon through multi-risk assessment and multi-component resilience assessment. Specifically, a new multi-component resilience index is proposed to measure (a) hazard-induced cumulative loss of functionality, (b) opportunity-induced cumulative gain of functionality, and (c) non-hazard-induced cumulative loss of functionality. The case study results indicate that all three types of risk factors contribute to the overall resilience index significantly and ignoring any one of them may result in inaccurate supply chain performance and resilience assessment

    Does a home-based interview with a chronically ill patient help medical students become more patient-centred? A randomised controlled trial.

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    BACKGROUND While patient-centred care improves patient outcomes, studies have shown that medical students become less patient-centred with time, so it is crucial to devise interventions that prevent this. We sought to determine whether first-year medical students who had a structured home-based interview with a chronically ill patient became more patient-centred than those who had a sham intervention. METHODS This randomised controlled trial assigned first-year students from the University of Bern, Switzerland, to either an interview with a chronically ill patient at the patient's home or to a sham comparator. We used the PPOS-D12 questionnaire to measure students' levels of patient-centredness at baseline, and changes in these levels during their longitudinal primary care clerkship. RESULTS A total of 317 students participated. Patient-centred attitudes increased during the study. A home-based interview with a chronically ill patient had no additional effect. Being female and having been exposed to patients before medical school were associated with being more patient-centred at baseline. Students were less patient-centred than their General Practitioner teachers. CONCLUSIONS A structured, home-based interview with a chronically ill patient did not change students' patient-centred attitudes, so cannot be recommended as a way to influence those attitudes. However, patient-centred attitudes increased during the students' first year of study, possibly because of their longitudinal primary care clerkship. TRIAL REGISTRATION Clinicaltrials.gov reference: NCT03722810 , registered 29th October 2018

    100 Jahre Zoff: die Geschichte der Zürcher Studierendenzeitung

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    Die Zürcher Studierendenzeitung (ZS), 1923 unter dem Namen «Zürcher Student» gegründet, ist eine wache Beobachterin des Zeitgeschehens. Sie diente Generationen von Studierenden der Universität Zürich und der ETH als Sprachrohr und publizistisches Versuchslabor. Viele ehemalige Redaktionsmitglieder wurden später zu namhaften Journalistinnen und Journalisten, auch entstand aus der ZS über Umwege die Wochenzeitung (WOZ). Mehrmals totgesagt, aber immer noch sehr lebendig, feiert die ZS dieses Jahr ihren 100. Geburtstag. «100 Jahre Zoff» vereint zu diesem Jubiläum anregende und unterhaltsame Beiträge, die die Geschichte des Blatts und seine Sicht auf die Welt beleuchten. Stets am Puls der Zeit, war und ist die ZS ein Spiegel der Stadt, ihrer Universität und des Weltgeschehens

    Positive Correlation between Pesticide Consumption and Longevity in Solitary Bees: Are We Overlooking Fitness Trade-Offs?

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    The ubiquitous use of pesticides is one major driver for the current loss of biodiversity, and the common practice of simultaneously applying multiple agrochemicals may further contribute. Insect toxicology currently has a strong focus on survival to determine the potential hazards of a chemical routinely used in risk evaluations. However, studies revealing no effect on survival or even indicating enhanced survival are likely to be misleading, if potential trade-offs between survival and other physiological factors are overlooked. Here, we used standard laboratory experiments to investigate the sublethal (i.e., food consumption) and lethal (i.e., survival) effects of two common agricultural pesticides (Roundup® and clothianidin) on adult female solitary bees, Osmia bicornis. The data showed no significant effect of the treatment on cumulative survival; however, a significant positive correlation between herbicide and insecticide exposure and age was revealed, i.e., bees exposed to higher dosages lived longer. As no significant differences in daily food consumption were observed across treatment groups, increased food intake can be excluded as a factor leading to the prolonged survival. While this study does not provide data on fitness effects, two previous studies using solitary bees observed significant negative effects of neonicotinoid insecticides on fitness, yet not on survival. Thus, we conjecture that the observed non-significant effects on longevity may result from a trade-off between survival and reproduction. The data suggest that a focus on survival can lead to false-negative results and it appears inevitable to include fitness or at least tokens of fitness at the earliest stage in future risk assessments

    The influence of a fermentation-resistant glucose diet on the glucose concentration and other metabolites in portal and jugular blood in cows

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    The goal of this study was to determine the effect of fermentation-resistant glucose on the glucose concentration and other metabolites in portal and jugular blood in 15 non-lactating cows. In all cows, an indwelling catheter was placed in the left jugular vein and the portal vein for collection of blood samples. Five control cows were fed hay as a normal diet, five control cows were fed straw to induce an energy deficit and five cows were fed hay and they received additionally 2000 g of a fermentation-resistant D-glucose product. The glucose concentration in jugular and portal blood was not influenced by feeding. The concentration of urea and bile acids were significantly higher in portal blood than jugular blood. There was no difference between portal and jugular blood of glucose and total solids. Diet had a significant effect on the concentrations of ammonia, urea, free fatty acids and triglycerides. The concentrations of ammonia and urea were higher in blood of cows fed straw than in blood of cows fed either hay or a fermentation-resistant glucose product. The concentration of urea remained constant in cows fed hay, but increased in cows fed straw and decreased in cows fed a fermentation-resistant glucose product. The concentration of free fatty acids and triglycerides were significantly higher in cows fed a fermentation-resistant glucose product than in cows fed hay. In the present study, a single administration of 300 g of fermentation-resistant glucose did not affect the concentration of blood glucose. Therefore, despite ongoing promotion of such products, there is no indication at this time that administration of fermentation-resistant glucose to cows at the start of lactation results in an increase in blood glucose concentration
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