1,728 research outputs found
Mirror reflectometer based on optical cavity decay time
Described is a reflectometer capable of making reflectivity measurements of low-loss highly reflecting mirror coatings and transmission measurements of low-loss antireflection coatings. The technique directly measures the intensity decay time of an optical cavity comprised of low-loss elements. We develop the theoretical framework for the device and discuss in what conditions and to what extent the decay time represents a true measure of mirror reflectivity. Current apparatus provides a decay time resolution of 10 nsec and has demonstrated a cavity total loss resolution of 5 ppm
Green, hybrid, or grey disaster risk reduction measures: what shapes public preferences for nature-based solutions?
Nature-based solutions (NbS) contrast with grey infrastructure measures to reduce risk from natural hazards. Using natural and sustainable measures (green) or combining green with grey elements (hybrid) can provide important co-benefits beyond risk reduction. Thanks to their co-benefits and flexibility across a range of possible climate change futures, NbS are sometimes referred to as 'win-win' or 'no-regret' measures. The success of NbS and associated projects often relies on the public for co-creation, co-implementation, and long-term sustainable use, monitoring, and management. However, the relative importance of NbS benefits is defined by the perceptions and underlying values of stakeholders with potentially divergent interests.
It is unclear what measures at-risk individuals may prefer on the green-hybrid-grey spectrum and what shapes their preferences, including perceived benefits and potential regret. Identifying public (mis)perceptions, expectations, objectives, and what underlies these can inform communication and project framing, engagement, and ultimately increase public acceptance and continued uptake of NbS. We use citizen surveys at three distinct European sites where NbS are being planned and in-depth focus groups as a follow-up in the site at risk of landslides (Catterline, Scotland). Preferences and their drivers for measures on the green-hybrid-grey spectrum are assessed, focusing on public perceptions of NbS effectiveness, risk, and nature.
We find that although wildlife habitat and aesthetics as co-benefits are important, reducing risk is of primary concern. Uncertainty in the strength and effectiveness of NbS, as one of 13 qualitative factors we identify, drives public preferences towards hybrid measures - seen as balancing green and grey trade-offs. Misperceptions and a demand for NbS information should be addressed with experiential learning, combined with transparent two-way communication of expectations. We urge caution and further research regarding emphasizing co-benefits and the 'natural' framing of NbS when risk reduction is the primary public objective
Quantum tunneling as a classical anomaly
Classical mechanics is a singular theory in that real-energy classical
particles can never enter classically forbidden regions. However, if one
regulates classical mechanics by allowing the energy E of a particle to be
complex, the particle exhibits quantum-like behavior: Complex-energy classical
particles can travel between classically allowed regions separated by potential
barriers. When Im(E) -> 0, the classical tunneling probabilities persist.
Hence, one can interpret quantum tunneling as an anomaly. A numerical
comparison of complex classical tunneling probabilities with quantum tunneling
probabilities leads to the conjecture that as ReE increases, complex classical
tunneling probabilities approach the corresponding quantum probabilities. Thus,
this work attempts to generalize the Bohr correspondence principle from
classically allowed to classically forbidden regions.Comment: 12 pages, 7 figure
Comparing index-based vulnerability assessments in the Mississippi Delta: Implications of contrasting theories, indicators, and aggregation methodologies
There are many index-based approaches for assessing vulnerability to socio-natural hazards with differences in underlying theory, indicator selection and aggregation methodology. Spatially explicit output scores depend on these characteristics and contrasting approaches can therefore lead to very different policy implications. These discrepancies call for more critical reflection on index design and utility, a discussion that has not kept pace with the impetus for vulnerability assessments and respective index creation and application following the Hyogo Framework for Action 2005ā2015. Comparing index outputs is an effective approach in this regard. Here, the Social Vulnerability Index (SoVIĀ®) and the vulnerability component of the Global Delta Risk Index (GDRI) are applied at census tract level in the Mississippi Delta and visually and quantitatively compared. While the SoVIĀ® is grounded in the hazard/risk research paradigm with primarily socio-economic indicators and an inductive principal component methodology, the GDRI incorporates advancements from sustainability science with ecosystem-based indicators and a modular hierarchical design. Maps, class rank changes, and correlations are used to assess the convergence and divergence of these indexes across the delta. Results show that while very different theoretical frameworks influence scores through indicator selection, methodology of index calculation has an even greater effect on output. Within aggregative methodology, the treatment of inter-indicator correlation is decisive. Implications include the need for an increased focus on index methodology and validation of results, transparency, and critical reflection regarding assessment limitations, as our results imply that contradictory risk reduction policies could be considered depending on the assessment methodology used
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Identification of novel myeloma-specific XBP1 peptides able to generate cytotoxic T lymphocytes: A potential therapeutic application in multiple myeloma
The purpose of these studies was to identify HLA-A2+ immunogenic peptides derived from XBP1 antigens to induce a multiple myeloma (MM)-specific immune response. Six native peptides from non-spliced XBP1 antigen and three native peptides from spliced XBP1 antigen were selected and evaluated for their HLA-A2 specificity. Among them,, XBP1 and XBP1 peptides showed the highest level of binding affinity, but not stability to HLA-A2 molecules. Novel heteroclitic XBP1 peptides, YISPWILAV or YLFPQLISV, demonstrated a significant improvement in HLA-A2 stability from their native or XBP1 peptide, respectively. Cytotoxic T lymphocytes generated by repeated stimulation of CD3+ T cells with each HLA-A2-specific heteroclitic peptide showed an increased percentage of CD8+ (cytotoxic) and CD69+/CD45RO+ (activated memory) T cells and a lower percentage of CD4+ (helper) and CD45RA+/CCR7+ (naĆÆve) T cells, which were distinct from the control T cells. Functionally, the CTLs demonstrated MM-specific and HLA-A2-restricted proliferation, IFN-Ī³ secretion and cytotoxic acivity in response to MM cell lines and importantly, cytotoxicty against primary MM cells. These data demonstrate the distinct immunogenic characteristics of unique heteroclitic XBP1 peptides which induce MM-specific CTLs and highlights their potential application for immunotherapy to treat the patients with MM or its pre-malignant condition
Social-ecological systems approach for adaptation to climate change
Adaptation to climate change has become part of national development programs (e.g., National Adaptation Planning). Though communities are adapting to climate change across the world, this perspective argues that understanding social and ecological systems requires greater attention to enhance resilience for achieving and moving beyond the Sustainable Development Goals (SDGs) in response to climate change across the world. In addition, based on a systematic literature review, this perspective identifies key research gaps and addresses relevant key challenges and future research direction for social and ecological systems (SES) adaptation to climate change. Ultimately, this may also help move from the existing limits to adaptation (intolerable risks through adaptive actions) concept to social-ecological limits to adaptation and offers an opportunity to integrate adaptation to climate change in development planning by considering both SES
Complex Trajectories in a Classical Periodic Potential
This paper examines the complex trajectories of a classical particle in the
potential V(x)=-cos(x). Almost all the trajectories describe a particle that
hops from one well to another in an erratic fashion. However, it is shown
analytically that there are two special classes of trajectories x(t) determined
only by the energy of the particle and not by the initial position of the
particle. The first class consists of periodic trajectories; that is,
trajectories that return to their initial position x(0) after some real time T.
The second class consists of trajectories for which there exists a real time T
such that . These two classes of classical trajectories
are analogous to valence and conduction bands in quantum mechanics, where the
quantum particle either remains localized or else tunnels resonantly (conducts)
through a crystal lattice. These two special types of trajectories are
associated with sets of energies of measure 0. For other energies, it is shown
that for long times the average velocity of the particle becomes a fractal-like
function of energy.Comment: 14 pages, 13 figure
Risk tolerance as a complementary concept to risk perception of natural hazards: a conceptual review and application
There is a longstanding assumption that if people perceive a risk as high, they will act to reduce it. In fact, research has shown a lack of consistently strong causal relations between risk perception (RP) and mitigative behaviorāthe so-called ārisk perception paradox.ā Despite a recent increase in research on RP, individualsā risk tolerance (RT; or demand for risk reduction) only rarely appears as a consideration for explaining behavioral response to natural hazards. To address this research gap, we first systematically review relevant literature and find that RT has been directly assessed or operationalized using perceived thresholds related to costs and benefits of risk reduction measures, risk consequences, hazard characteristics, behavioral responses, or affective reactions. It is either considered a component or a result of RP. We then use survey data of individualsā RP, RT, and behavioral intention to assess relations among these variables. Comparing across three European study sites, ābehavioral intentionā is assessed as the public's willingness to actively support the implementation of nature-based solutions to reduce disaster risk. A series of tests using regression models shows RT significantly explains variance in behavioral intention and significantly contributes additional explanatory power beyond RP in all three sites. In two sites, RT is also a significant partial mediator of the relation between RP and behavior. Taken together, our findings demand further conceptual and empirical research on individualsā RT and its systematic consideration as a determinant for (in)action in response to natural hazards
Egalitarian justice and expected value
According to all-luck egalitarianism, the differential distributive effects of both brute luck, which defines the outcome of risks which are not deliberately taken, and option luck, which defines the outcome of deliberate gambles, are unjust. Exactly how to correct the effects of option luck is, however, a complex issue. This article argues that (a) option luck should be neutralized not just by correcting luck among gamblers, but among the community as a whole, because it would be unfair for gamblers as a group to be disadvantaged relative to non-gamblers by bad option luck; (b) individuals should receive the warranted expected results of their gambles, except insofar as individuals blamelessly lacked the ability to ascertain which expectations were warranted; and (c) where societal resources are insufficient to deliver expected results to gamblers, gamblers should receive a lesser distributive share which is in proportion to the expected results. Where all-luck egalitarianism is understood in this way, it allows risk-takers to impose externalities on non-risk-takers, which seems counterintuitive. This may, however, be an advantage as it provides a luck egalitarian rationale for assisting ānegligent victimsā
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