483 research outputs found
Communications and tracking expert systems study
The original objectives of the study consisted of five broad areas of investigation: criteria and issues for explanation of communication and tracking system anomaly detection, isolation, and recovery; data storage simplification issues for fault detection expert systems; data selection procedures for decision tree pruning and optimization to enhance the abstraction of pertinent information for clear explanation; criteria for establishing levels of explanation suited to needs; and analysis of expert system interaction and modularization. Progress was made in all areas, but to a lesser extent in the criteria for establishing levels of explanation suited to needs. Among the types of expert systems studied were those related to anomaly or fault detection, isolation, and recovery
The impact of Arctic warming on the midlatitude jetstream: Can it? Has it? Will it?
Copyright © 2015 John Wiley & Sons, LtdThe Arctic lower atmosphere has warmed more rapidly than that of the globe as a whole, and this has been accompanied by unprecedented sea ice melt. Such large environmental changes are already having profound impacts on the flora, fauna, and inhabitants of the Arctic region. An open question, however, is whether these Arctic changes have an effect on the jet-stream and thereby influence weather patterns farther south. This broad question has recently received a lot of scientific and media attention, but conclusions appear contradictory rather than consensual. We argue that one point of confusion has arisen due to ambiguities in the exact question being posed. In this study, we frame our inquiries around three distinct questions: Can Arctic warming influence the midlatitude jet-stream? Has Arctic warming significantly influenced the midlatitude jet-stream? Will Arctic warming significantly influence the midlatitude jet-stream? We argue that framing the discussion around the three questions: Can it?, Has it?, and Will it? provides insight into the common themes emerging in the literature as well as highlights the challenges ahead
Addressing Africa's Energy Dilemma
This chapter discusses how the ongoing low-carbon energy transformation could reshape geopolitics within Africa and between the continent and the rest of the world. The chapter first attempts to define what 'transition' means in African contexts and if the concept applies at all to African dynamics. It then delves into the drivers and modalities of Africa's alleged shift to finally explore geopolitical dynamics, questioning whether Africa is still the locus for the global supply of natural resources, introducing patterns of engagement between Africa and international/regional actors, and finally presenting the socio-economic implications of the shift. We conclude that while the venues and sources of geopolitical interest might change in the new geopolitical order that the transition to renewable energy implies, the content and modalities of interaction may see a continuity with the past, namely, dependence on external financing and technology. With yet at least one novelty: increased relevance of regional interdependencies
A Data-Based Console Logger for Mission Operations Team Coordination
Concepts and prototypes1,2 are discussed for a data-based console logger (D-Logger) to meet new challenges for coordination among flight controllers arising from new exploration mission concepts. The challenges include communication delays, increased crew autonomy, multiple concurrent missions, reduced-size flight support teams that include multidisciplinary flight controllers during quiescent periods, and migrating some flight support activities to flight controller offices. A spiral development approach has been adopted, making simple, but useful functions available early and adding more extensive support later. Evaluations have guided the development of the D-Logger from the beginning and continue to provide valuable user influence about upcoming requirements. D-Logger is part of a suite of tools designed to support future operations personnel and crew. While these tools can be used independently, when used together, they provide yet another level of support by interacting with one another. Recommendations are offered for the development of similar projects
Responses in rainbow trout (Oncorhynchus mykiss) to increasing dietary doses of lupinine, the main quinolizidine alkaloid found in yellow lupins (Lupinus luteus)
This experiment investigated the effect of increasing dietary doses of lupinine, the main quinolizidine alkaloid in Lupinus luteus, on feed intake, growth performance, tissue histology and nutritional composition of rainbow trout (Oncorhynchus mykiss). Duplicate groups of rainbow trout (initial body weight of 330g) were fed extruded fish meal based diets containing 0, 50, 75, 100, 250, 500, 1000 and 5000mg lupininekg-1 for 60days. Feed intake and growth were reduced in response to dietary lupinine, best fit by quadratic regression. Based on these results, the practical tolerance level of lupinine, with regard to growth and feed intake, was ≤100mgkg-1 feed. Carcass composition did not vary among treatments. Despite a depletion of glycogen and lipid stores in the hepatocytes, lupinine did not induce any morphological changes in spleen, kidney, heart or intestinal tissues.These results indicate that the lupinine possesses a strong anti-palatability effect, but does not appear to pose short-term health risks for rainbow trout. © 2011 Elsevier B.V
Divergent consensuses on Arctic amplification influence on midlatitude severe winter weather
The article of record as published may be found at https://doi.org/10.1038/s41558-019-0662-yWe thank R. Blackport, C. Deser, L. Sun, J. Screen and D. Smith for discussions and
suggested revisions to the manuscript. We also thank J. Screen and L. Sun for model data.
A. Amin helped to create Fig. 2. US CLIVAR logistically and financially supported the
Arctic-Midlatitude Working Group and Arctic Change and its Influence on Mid-Latitude
Climate and Weather workshop that resulted in this article. J.C. is supported by the US
National Science Foundation grants AGS-1657748 and PLR-1504361, 1901352. M.W.
acknowledges funding by the Deutsche Forschungsgemeinschaft project no. 268020496–
TRR 172, within the Transregional Collaborative Research Center “Arctic Amplification:
Climate Relevant Atmospheric and Surface Processes, and Feedback Mechanisms (AC)3
”.
T.V. was supported by the Academy of Finland grant 317999. J.O. was supported by the
NOAA Arctic Research Program. J.F. was supported by the Woods Hole Research Center.
S.W. and H.G. are supported by the US DOE Award Number DE-SC0016605. J.Y. was
supported by the Korea Meteorological Administration Research and Development
Program under grant KMI2018-01015 and National Research Foundation grant
NRF_2017R1A2B4007480. D.H. is supported by the Helmholtz Association of German
Research Centers (grant FKZ HRSF-0036, project POLEX). The authors acknowledge the
World Climate Research Programme’s Working Group on Coupled Modelling, which is
responsible for CMIP, and thank the climate modelling groups (listed in Supplementary
Table 1) for producing and making available their model output. For CMIP, the US
Department of Energy’s PCMDI provides coordinating support and led development of
software infrastructure in partnership with the Global Organization for Earth System
Science Portals.The Arctic has warmed more than twice as fast as the global average since the late twentieth century, a phenomenon known as
Arctic amplification (AA). Recently, there have been considerable advances in understanding the physical contributions to AA,
and progress has been made in understanding the mechanisms that link it to midlatitude weather variability. Observational
studies overwhelmingly support that AA is contributing to winter continental cooling. Although some model experiments sup port the observational evidence, most modelling results show little connection between AA and severe midlatitude weather or
suggest the export of excess heating from the Arctic to lower latitudes. Divergent conclusions between model and observational
studies, and even intramodel studies, continue to obfuscate a clear understanding of how AA is influencing midlatitude weather
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Selecting CMIP5 GCMs for downscaling over multiple regions
The unprecedented availability of 6-hourly data from a multi-model GCM ensemble in the CMIP5 data archive presents the new opportunity to dynamically downscale multiple GCMs to develop high-resolution climate projections relevant to detailed assessment of climate vulnerability and climate change impacts. This enables the development of high resolution projections derived from the same set of models that are used to characterise the range of future climate changes at the global and large-scale, and as assessed in the IPCC AR5. However, the technical and human resource required to dynamically-downscale the full CMIP5 ensemble are significant and not necessary if the aim is to develop scenarios covering a representative range of future climate conditions relevant to a climate change risk assessment. This paper illustrates a methodology for selecting from the available CMIP5 models in order to identify a set of 8–10 GCMs for use in regional climate change assessments. The selection focuses on their suitability across multiple regions—Southeast Asia, Europe and Africa. The selection (a) avoids the inclusion of the least realistic models for each region and (b) simultaneously captures the maximum possible range of changes in surface temperature and precipitation for three continental-scale regions. We find that, of the CMIP5 GCMs with 6-hourly fields available, three simulate the key regional aspects of climate sufficiently poorly that we consider the projections from those models ‘implausible’ (MIROC-ESM, MIROC-ESM-CHEM, and IPSL-CM5B-LR). From the remaining models, we demonstrate a selection methodology which avoids the poorest models by including them in the set only if their exclusion would significantly reduce the range of projections sampled. The result of this process is a set of models suitable for using to generate downscaled climate change information for a consistent multi-regional assessment of climate change impacts and adaptation
Arctic change and possible influence on mid-latitude climate and weather: a US CLIVAR White Paper
The Arctic has warmed more than twice as fast as the global average since the mid 20th century,
a phenomenon known as Arctic amplification (AA). These profound changes to the Arctic system
have coincided with a period of ostensibly more frequent events of extreme weather across the
Northern Hemisphere (NH) mid-latitudes, including extreme heat and rainfall events and recent
severe winters. Though winter temperatures have generally warmed since 1960 over mid-to-high
latitudes, the acceleration in the rate of warming at high-latitudes, relative to the rest of the NH,
started approximately in 1990. Trends since 1990 show cooling over the NH continents, especially
in Northern Eurasia.
The possible link between Arctic change and mid-latitude climate and weather has spurred a rush
of new observational and modeling studies. A number of workshops held during 2013-2014 have
helped frame the problem and have called for continuing and enhancing efforts for improving
our understanding of Arctic-mid-latitude linkages and its attribution to the occurrence of extreme
climate and weather events. Although these workshops have outlined some of the major challenges
and provided broad recommendations, further efforts are needed to synthesize the diversified
research results to identify where community consensus and gaps exist.
Building upon findings and recommendations of the previous workshops, the US CLIVAR Working
Group on Arctic Change and Possible Influence on Mid-latitude Climate and Weather convened an
international workshop at Georgetown University in Washington, DC, on February 1-3, 2017. Experts
in the fields of atmosphere, ocean, and cryosphere sciences assembled to assess the rapidly evolving
state of understanding, identify consensus on knowledge and gaps in research, and develop specific
actions to accelerate progress within the research community. With more than 100 participants,
the workshop was the largest and most comprehensive gathering of climate scientists to address
the topic to date. In this white paper, we synthesize and discuss outcomes from this workshop and
activities involving many of the working group members
Addressing the welfare needs of farmed lumpfish: knowledge gaps, challenges and solutions
Lumpfish (Cyclopterus lumpus L.) are increasingly being used as cleaner fish to control parasitic sea lice, one of the most important threats to salmon farming. However, lumpfish cannot survive feeding solely on sea lice, and their mortality in salmon net pens can be high, which has welfare, ethical and economic implications. The industry is under increasing pressure to improve the welfare of lumpfish, but little guidance exists on how this can be achieved. We undertook a knowledge gap and prioritisa tion exercise using a Delphi approach with participants from the fish farming sector, animal welfare, academia and regulators to assess consensus on the main challenges and potential solutions for improving lumpfish welfare. Consensus among participants
on the utility of 5 behavioural and 12 physical welfare indicators was high (87–89%), reliable (Cronbach's alpha = 0.79, 95CI = 0.69–0.92) and independent of participant background. Participants highlighted fin erosion and body damage as the most use ful and practical operational welfare indicators, and blood parameters and behav ioural indicators as the least practical. Species profiling revealed profound differences between Atlantic salmon and lumpfish in relation to behaviour, habitat preferences, nutritional needs and response to stress, suggesting that applying a common set of welfare standards to both species cohabiting in salmon net-pens may not work well for lumpfish. Our study offers 16 practical solutions for improving the welfare of lumpfish and illustrates the merits of the Delphi approach for achieving consensus among stakeholders on welfare needs, targeting research where is most needed and generating workable solutions.info:eu-repo/semantics/publishedVersio
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Atmospheric impact of Arctic Sea ice loss in a coupled ocean–atmosphere simulation
The atmospheric response to an idealized decline in Arctic sea ice is investigated in a novel fully coupled climate model experiment. In this experiment two ensembles of single-year model integrations are performed starting on 1 April, the approximate start of the ice melt season. By perturbing the initial conditions of sea ice thickness (SIT), declines in both sea ice concentration and SIT, which result in sea ice distributions that are similar to the recent sea ice minima of 2007 and 2012, are induced. In the ice loss regions there are strong (~3 K) local increases in sea surface temperature (SST); additionally, there are remote increases in SST in the central North Pacific and subpolar gyre in the North Atlantic. Over the central Arctic there are increases in surface air temperature (SAT) of ~8 K due to increases in ocean–atmosphere heat fluxes. There are increases in SAT over continental North America that are in good agreement with recent changes as seen by reanalysis data. It is estimated that up to two-thirds of the observed increase in SAT in this region could be related to Arctic sea ice loss. In early summer there is a significant but weak atmospheric circulation response that projects onto the summer North Atlantic Oscillation (NAO). In early summer and early autumn there is an equatorward shift of the eddy-driven jet over the North Atlantic as a result of a reduction in the meridional temperature gradients. In winter there is no projection onto a particular phase of the NAO
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