361 research outputs found
Plane torsion waves in quadratic gravitational theories
The definition of the Riemann-Cartan space of the plane wave type is given.
The condition under which the torsion plane waves exist is found. It is
expressed in the form of the restriction imposed on the coupling constants of
the 10-parametric quadratic gravitational Lagrangian. In the mathematical
appendix the formula for commutator of the variation operator and Hodge
operator is proved. This formula is applied for the variational procedure when
the gravitational field equations are obtained in terms of the exterior
differential forms.Comment: 3 May 1998. - 11
Seasonal Spatial Segregation in Blue Sharks (Prionace glauca) by Sex and Size Class in the Northeast Pacific Ocean
Aim: Animal tracking can provide unique insights into the ecology and conservation of marine species, such as the partitioning of habitat, including differences between life history stages or sexes, and can inform fisheries stock assessments, bycatch reduction and spatial management such as dynamic management.
Location: Northeast Pacific Ocean.
Methods: We used satellite tracking data from 47 blue sharks (Prionace glauca) from the Northeast Pacific to determine movements and home range along the west coast of North America, and sex–size class (immature females, mature males) specific habitat preferences using boosted regression trees. Using a suite of static and dynamic environmental variables, we determined distribution and habitat preferences across summer and fall for each sex–size class.
Results: We found that there was spatial segregation between sex–size classes particularly in the summer months with immature females found largely north of 33°N, and males south of 35°N. In fall, females travelled south, resulting in an overlap in distributions south of 37°N. Sea surface temperature (SST), latitude and longitude were top predictors. However, immature females and adult males demonstrated unique habitat preferences including SST, with immature females preferring cooler temperatures (SST \u3c 15°C) than adult males in summer, and a broader band of SST than adult males in fall. All models performed well, explaining 50%–67% of deviance, and 23%–41% of deviance when predictions were cross‐validated.
Main conclusions: We provide first insights into coastal movements and habitat preferences of blue sharks in the Northeast Pacific. We found that immature females undergo a seasonal southward migration in this more coastal habitat, similar to patterns observed in the North Atlantic. We also found some overlap between adult males and immature females in fall months, suggesting the importance of more coastal habitat in managing this species, particularly in determining population structure for blue shark stock assessments, and reducing blue shark bycatch
A Geometric Measure for the Violation of Utility Maximization
Revealed Preference offers nonparametric tests for whether consumption observations can be rationalized by a utility function. If a consumer is inconsistent with GARP, we might need a measure for the severity of inconsistency. One widely used measure is the Afriat efficiency index (AEI). We propose a new measure based on the extent to which the indifference surfaces intersect the budget hyperplanes. The measure is intuitively appealing and, as a cutoff-rule evaluated by Monte Carlo experiments, performs very well compared to the AEI. The results suggest that the new measure is better suited to capture small deviations from utility maximation
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A common framework for approaches to extreme event attribution
The extent to which a given extreme weather or climate event is attributable to anthropogenic climate change
is a question of considerable public interest. From a scientific perspective, the question can be framed in various ways, and the answer depends very much on the framing. One such framing is a risk-based approach, which answers the question probabilistically, in terms of a change in likelihood of a class of event similar to the one in question, and natural variability is treated as noise. A rather different framing is a storyline approach, which examines the role of the various factors contributing
to the event as it unfolded, including the anomalous
aspects of natural variability, and answers the question deterministically. It is argued that these two apparently irreconcilable approaches can be viewed within a common framework, where the most useful level of conditioning will depend on the question being asked and the uncertainties involved
Lived Experience-Led Research Agenda to Address Early Death in People With a Diagnosis of a Serious Mental Illness: A Consensus Statement
Importance People with serious mental illness (SMI), defined as a diagnosis of schizophrenia spectrum disorder, bipolar disorder, or disabling major depressive disorder) die approximately 10 to 25 years earlier than the general population.
Objective To develop the first-ever lived experience–led research agenda to address early mortality in people with SMI.
Evidence Review A virtual 2-day roundtable comprising 40 individuals convened on May 24 and May 26, 2022, and used a virtual Delphi method to arrive at expert group consensus. Participants responded to 6 rounds of virtual Delphi discussion via email that prioritized research topics and agreement on recommendations. The roundtable was composed of individuals with lived experience of mental health and/or substance misuse, peer support specialists, recovery coaches, parents and caregivers of people with SMI, researchers and clinician-scientists with and without lived experience, policy makers, and patient-led organizations. Twenty-two of 28 (78.6%) of the authors who provided data represented people with lived experiences. Roundtable members were selected by reviewing the peer-reviewed and gray literature on early mortality and SMI, direct email, and snowball sampling.
Findings The following recommendations are presented in order of priority as identified by the roundtable participants: (1) improve the empirical understanding of the direct and indirect social and biological contributions of trauma on morbidity and early mortality; (2) advance the role of family, extended families, and informal supporters; (3) recognize the importance of co-occurring disorders and early mortality; (4) redefine clinical education to reduce stigma and support clinicians through technological advancements to improve diagnostic accuracy; (5) examine outcomes meaningful to people with an SMI diagnosis, such as loneliness and sense of belonging, and stigma and their complex relationship with early mortality; (6) advance the science of pharmaceuticals, drug discovery, and choice in medication use; (7) use precision medicine to inform treatment; and (8) redefine the terms system literacy and health literacy.
Conclusions and Relevance The recommendations of this roundtable are a starting point for changing practice and highlighting lived experience–led research priorities as an option to move the field forward.publishedVersio
The histochemistry of thiols and disulphides. IV. Protective fixation by organomercurial-formalin mixtures
Formation of mercaptides as the result of adding organomercuric salts to neutral formalin used for fixation was found to protect protein thiols from autoxidation, provided the tissues were washed in distilled and not tap water. Such bloking, in contrast to that given by HgCl 2 , could be reversed quantitatively by mercaptoethanol made strongly acid to keep it from reducing disulphides. However, some cleavage of disulphides by the mercurials themselves caused slight arbfactual thiol staining in a limited number of sites. Three of the nine compounds tested are sufficiently soluble to penetrate tissues with reasonable speed, stable enough to preclude more than incidental mercurial deposits and currently available commercially. Of them, the diuretic mercurial Mersalyl is at present the protecting, agent of choice since methyl- and ethylmercuric chlorides are too toxic to recommend for routine use.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42846/1/10735_2005_Article_BF01066541.pd
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Attribution: how is it relevant for loss and damage policy and practice?
Attribution has become a recurring issue in discussions about Loss and Damage (L&D). In this highly-politicised context, attribution is often associated with responsibility and blame; and linked to debates about liability and compensation. The aim of attribution science, however, is not to establish responsibility, but to further scientific understanding of causal links between elements of the Earth System and society. This research into causality could inform the management of climate-related risks through improved understanding of drivers of relevant hazards, or, more widely, vulnerability and exposure; with potential benefits regardless of political positions on L&D. Experience shows that it is nevertheless difficult to have open discussions about the science in the policy sphere. This is not only a missed opportunity, but also problematic in that it could inhibit understanding of scientific results and uncertainties, potentially leading to policy planning which does not have sufficient scientific evidence to support it. In this chapter, we first explore this dilemma for science-policy dialogue, summarising several years of research into stakeholder perspectives of attribution in the context of L&D. We then aim to provide clarity about the scientific research available, through an overview of research which might contribute evidence about the causal connections between anthropogenic climate change and losses and damages, including climate science, but also other fields which examine other drivers of hazard, exposure, and vulnerability. Finally, we explore potential applications of attribution research, suggesting that an integrated and nuanced approach has potential to inform planning to avert, minimise and address losses and damages. The key messages are
In the political context of climate negotiations, questions about whether losses and damages can be attributed to anthropogenic climate change are often linked to issues of responsibility, blame, and liability.
Attribution science does not aim to establish responsibility or blame, but rather to investigate drivers of change.
Attribution science is advancing rapidly, and has potential to increase understanding of how climate variability and change is influencing slow onset and extreme weather events, and how this interacts with other drivers of risk, including socio-economic drivers, to influence losses and damages.
Over time, some uncertainties in the science will be reduced, as the anthropogenic climate change signal becomes stronger, and understanding of climate variability and change develops.
However, some uncertainties will not be eliminated. Uncertainty is common in science, and does not prevent useful applications in policy, but might determine which applications are appropriate. It is important to highlight that in attribution studies, the strength of evidence varies substantially between different kinds of slow onset and extreme weather events, and between regions. Policy-makers should not expect the later emergence of conclusive evidence about the influence of climate variability and change on specific incidences of losses and damages; and, in particular, should not expect the strength of evidence to be equal between events, and between countries.
Rather than waiting for further confidence in attribution studies, there is potential to start working now to integrate science into policy and practice, to help understand and tackle drivers of losses and damages, informing prevention, recovery, rehabilitation, and transformation
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