605 research outputs found
Device independent quantum key distribution secure against coherent attacks with memoryless measurement devices
Device independent quantum key distribution aims to provide a higher degree
of security than traditional QKD schemes by reducing the number of assumptions
that need to be made about the physical devices used. The previous proof of
security by Pironio et al. applies only to collective attacks where the state
is identical and independent and the measurement devices operate identically
for each trial in the protocol. We extend this result to a more general class
of attacks where the state is arbitrary and the measurement devices have no
memory. We accomplish this by a reduction of arbitrary adversary strategies to
qubit strategies and a proof of security for qubit strategies based on the
previous proof by Pironio et al. and techniques adapted from Renner.Comment: 13 pages. Expanded main proofs with more detail, miscellaneous edits
for clarit
The Hidden Curriculum of a Teacher Induction Program: Ontario Teacher Educatorsâ Perspectives
This article investigates the hidden curriculum of Ontarioâs New Teacher Induction Program (NTIP). The study involved interviews with 47 teacher educators from eight faculties of education. Responses revealed concerns about (a) who chooses the menâ tors, (b) the probationary status of new teachers, and (c) the evaluation of new teachâ ersâ competence. In the opinion of some teacher educators, the structure of NTIP may discourage new teachers from critiquing the system that employs them thus decreasâ ing the likelihood of their taking a critical democratic stance in their teaching. These findings have implications for any induction or mentorship program for new teachâ ers. Key Words: teacher education, mentorship, social justice, critical democratic, Ontario New Teacher Induction ProgramCet article porte sur les objectifs cachĂ©s du Programme dÊčinsertion professionnelle du nouveau personnel enseignant (PIPNPE) de lâOntario. Pour cette recherche, les auâ teurs ont interviewĂ© 47 professeurs de pĂ©dagogie dans huit facultĂ©s dâĂ©ducation. Ces entrevues rĂ©vĂšlent des inquiĂ©tudes au sujet (a) du mode de sĂ©lection des mentors, (b) du statut probatoire du nouveau personnel enseignant, (c) de lâĂ©valuation des compĂ©â tences du nouveau personnel enseignant. Selon certains des rĂ©pondants, la structure du PIPNPE peut dissuader certains nouveaux enseignants de critiquer le systĂšme qui les emploie, ce qui diminue les chances quâils prennent une orientation dĂ©mocratique critique dans leur enseignement. Ces observations ont des implications pour tout programme dâinsertion professionnelle ou de mentorat sâadressant au nouveau perâ sonnel enseignant. Mots clĂ©s : formation Ă lâenseignement, mentorat, justice sociale, critique, dĂ©mocratiâ que, Programme dÊčinsertion professionnelle du nouveau personnel enseignant de lâOntario.
Fractal Weyl law behavior in an open, chaotic Hamiltonian system
We numerically show fractal Weyl law behavior in an open Hamiltonian system
that is described by a smooth potential and which supports numerous
above-barrier resonances. This behavior holds even relatively far away from the
classical limit. The complex resonance wave functions are found to be localized
on the fractal classical repeller.Comment: 4 pages, 3 figures. to appear in Phys Rev
Testing axioms for Quantum Mechanics on Probabilistic toy-theories
In Ref. [1] one of the authors proposed postulates for axiomatizing Quantum
Mechanics as a "fair operational framework", namely regarding the theory as a
set of rules that allow the experimenter to predict future events on the basis
of suitable tests, having local control and low experimental complexity. In
addition to causality, the following postulates have been considered: PFAITH
(existence of a pure preparationally faithful state), and FAITHE (existence of
a faithful effect). These postulates have exhibited an unexpected theoretical
power, excluding all known nonquantum probabilistic theories. Later in Ref. [2]
in addition to causality and PFAITH, postulate LDISCR (local discriminability)
and PURIFY (purifiability of all states) have been considered, narrowing the
probabilistic theory to something very close to Quantum Mechanics. In the
present paper we test the above postulates on some nonquantum probabilistic
models. The first model, "the two-box world" is an extension of the
Popescu-Rohrlich model, which achieves the greatest violation of the CHSH
inequality compatible with the no-signaling principle. The second model "the
two-clock world" is actually a full class of models, all having a disk as
convex set of states for the local system. One of them corresponds to the "the
two-rebit world", namely qubits with real Hilbert space. The third model--"the
spin-factor"--is a sort of n-dimensional generalization of the clock. Finally
the last model is "the classical probabilistic theory". We see how each model
violates some of the proposed postulates, when and how teleportation can be
achieved, and we analyze other interesting connections between these postulate
violations, along with deep relations between the local and the non-local
structures of the probabilistic theory.Comment: Submitted to QIP Special Issue on Foundations of Quantum Informatio
Spatial tethering of kinases to their substrates relaxes evolutionary constraints on specificity
Signal transduction proteins are often multi-domain proteins that arose through the fusion of previously independent proteins. How such a change in the spatial arrangement of proteins impacts their evolution and the selective pressures acting on individual residues is largely unknown. We explored this problem in the context of bacterial two-component signalling pathways, which typically involve a sensor histidine kinase that specifically phosphorylates a single cognate response regulator. Although usually found as separate proteins, these proteins are sometimes fused into a so-called hybrid histidine kinase. Here, we demonstrate that the isolated kinase domains of hybrid kinases exhibit a dramatic reduction in phosphotransfer specificity in vitro relative to canonical histidine kinases. However, hybrid kinases phosphotransfer almost exclusively to their covalently attached response regulator domain, whose effective concentration exceeds that of all soluble response regulators. These findings indicate that the fused response regulator in a hybrid kinase normally prevents detrimental cross-talk between pathways. More generally, our results shed light on how the spatial properties of signalling pathways can significantly affect their evolution, with additional implications for the design of synthetic signalling systems.National Science Foundation (U.S.) (CAREER Award)National Science Foundation (U.S.). Graduate Research Fellowship Progra
Complexity of multi-dimensional spontaneous EEG decreases during propofol induced general anaesthesia
Emerging neural theories of consciousness suggest a correlation between a specific type of neural dynamical complexity and the level of consciousness: When awake and aware, causal interactions between brain regions are both integrated (all regions are to a certain extent connected) and differentiated (there is inhomogeneity and variety in the interactions). In support of this, recent work by Casali et al (2013) has shown that Lempel-Ziv complexity correlates strongly with conscious level, when computed on the EEG response to transcranial magnetic stimulation. Here we investigated complexity of spontaneous high-density EEG data during propofol-induced general anaesthesia. We consider three distinct measures: (i) Lempel-Ziv complexity, which is derived from how compressible the data are; (ii) amplitude coalition entropy, which measures the variability in the constitution of the set of active channels; and (iii) the novel synchrony coalition entropy (SCE), which measures the variability in the constitution of the set of synchronous channels. After some simulations on Kuramoto oscillator models which demonstrate that these measures capture distinct âflavoursâ of complexity, we show that there is a robustly measurable decrease in the complexity of spontaneous EEG during general anaesthesia
Stakeholder narratives on trypanosomiasis, their effect on policy and the scope for One Health
Background
This paper explores the framings of trypanosomiasis, a widespread and potentially fatal zoonotic disease transmitted by tsetse flies (Glossina species) affecting both humans and livestock. This is a country case study focusing on the political economy of knowledge in Zambia. It is a pertinent time to examine this issue as human population growth and other factors have led to migration into tsetse-inhabited areas with little historical influence from livestock. Disease transmission in new human-wildlife interfaces such as these is a greater risk, and opinions on the best way to manage this are deeply divided.
Methods
A qualitative case study method was used to examine the narratives on trypanosomiasis in the Zambian policy context through a series of key informant interviews. Interviewees included key actors from international organisations, research organisations and local activists from a variety of perspectives acknowledging the need to explore the relationships between the human, animal and environmental sectors.
Principal Findings
Diverse framings are held by key actors looking from, variously, the perspectives of wildlife and environmental protection, agricultural development, poverty alleviation, and veterinary and public health. From these viewpoints, four narratives about trypanosomiasis policy were identified, focused around four different beliefs: that trypanosomiasis is protecting the environment, is causing poverty, is not a major problem, and finally, that it is a Zambian rather than international issue to contend with. Within these narratives there are also conflicting views on the best control methods to use and different reasoning behind the pathways of response. These are based on apparently incompatible priorities of people, land, animals, the economy and the environment. The extent to which a One Health approach has been embraced and the potential usefulness of this as a way of reconciling the aims of these framings and narratives is considered throughout the paper.
Conclusions/Significance
While there has historically been a lack of One Health working in this context, the complex, interacting factors that impact the disease show the need for cross-sector, interdisciplinary decision making to stop rival narratives leading to competing actions. Additional recommendations include implementing: surveillance to assess under-reporting of disease and consequential under-estimation of disease risk; evidence-based decision making; increased and structurally managed funding across countries; and focus on interactions between disease drivers, disease incidence at the community level, and poverty and equity impacts
Antibodies from malaria-exposed Malians generally interact additively or synergistically with human vaccine-induced RH5 antibodies
Reticulocyte-binding protein homolog 5 (RH5) is a leading Plasmodium falciparum blood-stage vaccine candidate. Another possible candidate, apical membrane antigen 1 (AMA1), was not efficacious in malaria-endemic populations, likely due to pre-existing antimalarial antibodies that interfered with the activity of vaccine-induced AMA1 antibodies, as judged by in vitro growth inhibition assay (GIA). To determine how pre-existing antibodies interact with vaccine-induced RH5 antibodies, we purify total and RH5-specific immunoglobulin Gs (IgGs) from malaria-exposed Malians and malaria-naive RH5 vaccinees. Infection-induced RH5 antibody titers are much lower than those induced by vaccination, and RH5-specific IgGs show differences in the binding site between the two populations. In GIA, Malian polyclonal IgGs show additive or synergistic interactions with RH5 human monoclonal antibodies and overall additive interactions with vaccine-induced polyclonal RH5 IgGs. These results suggest that pre-existing antibodies will interact favorably with vaccine-induced RH5 antibodies, in contrast to AMA1 antibodies. This study supports RH5 vaccine trials in malaria-endemic regions
A systematic analysis of the human immune response to Plasmodium vivax
Background. The biology of Plasmodium vivax is markedly different from that of P. falciparum; how this shapes the immune response to infection remains unclear. To address this shortfall, we inoculated human volunteers with a clonal field isolate of P. vivax and tracked their response through infection and convalescence.
Methods. Participants were injected intravenously with blood-stage parasites and infection dynamics were tracked in real time by quantitative PCR. Whole blood samples were used for high dimensional protein analysis, RNA sequencing, and cytometry by time of flight, and temporal changes in the host response to P. vivax were quantified by linear regression. Comparative analyses with P. falciparum were then undertaken using analogous data sets derived from prior controlled human malaria infection studies.
Results. P. vivax rapidly induced a type I inflammatory response that coincided with hallmark features of clinical malaria. This acute-phase response shared remarkable overlap with that induced by P. falciparum but was significantly elevated (at RNA and protein levels), leading to an increased incidence of pyrexia. In contrast, T cell activation and terminal differentiation were significantly increased in volunteers infected with P. falciparum. Heterogeneous CD4+ T cells were found to dominate this adaptive response and phenotypic analysis revealed unexpected features normally associated with cytotoxicity and autoinflammatory disease.
Conclusion. P. vivax triggers increased systemic interferon signaling (cf P. falciparum), which likely explains its reduced pyrogenic threshold. In contrast, P. falciparum drives T cell activation far in excess of P. vivax, which may partially explain why falciparum malaria more frequently causes severe disease.
Trial registration. ClinicalTrials.gov NCT03797989.
Funding. The European Unionâs Horizon 2020 Research and Innovation programme, the Wellcome Trust, and the Royal Society
Holocene deglaciation drove rapid genetic diversification of Atlantic walrus
Rapid global warming is severely impacting Arctic ecosystems and is predicted to transform the abundance, distribution and genetic diversity of Arctic species, though these linkages are poorly understood. We address this gap in knowledge using palaeogenomics to examine how earlier periods of global warming influenced the genetic diversity of Atlantic walrus (Odobenus rosmarus rosmarus), a species closely associated with sea ice and shallow-water habitats. We analysed 82 ancient and historical Atlantic walrus mitochondrial genomes (mitogenomes), including now-extinct populations in Iceland and the Canadian Maritimes, to reconstruct the Atlantic walrus' response to Arctic deglaciation. Our results demonstrate that the phylogeography and genetic diversity of Atlantic walrus populations was initially shaped by the last glacial maximum (LGM), surviving in distinct glacial refugia, and subsequently expanding rapidly in multiple migration waves during the late Pleistocene and early Holocene. The timing of diversification and establishment of distinct populations corresponds closely with the chronology of the glacial retreat, pointing to a strong link between walrus phylogeography and sea ice. Our results indicate that accelerated ice loss in the modern Arctic may trigger further dispersal events, likely increasing the connectivity of northern stocks while isolating more southerly stocks putatively caught in small pockets of suitable habitat
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