Quantum probabilities as Bayesian probabilities

In the Bayesian approach to probability theory, probability quantifies a degree of belief for a single trial, without any a priori connection to limiting frequencies. In this paper we show that, despite being prescribed by a fundamental law, probabilities for individual quantum systems can be understood within the Bayesian approach. We argue that the distinction between classical and quantum probabilities lies not in their definition, but in the nature of the information they encode. In the classical world, maximal information about a physical system is complete in the sense of providing definite answers for all possible questions that can be asked of the system. In the quantum world, maximal information is not complete and cannot be completed. Using this distinction, we show that any Bayesian probability assignment in quantum mechanics must have the form of the quantum probability rule, that maximal information about a quantum system leads to a unique quantum-state assignment, and that quantum theory provides a stronger connection between probability and measured frequency than can be justified classically. Finally we give a Bayesian formulation of quantum-state tomography.Comment: 6 pages, Latex, final versio

Integrating evidence, politics and society: a methodology for the science–policy interface

There is currently intense debate over expertise, evidence and ‘post-truth’ politics, and how this is influencing policy formulation and implementation. In this article, we put forward a methodology for evidence-based policy making intended as a way of helping navigate this web of complexity. Starting from the premise of why it is so crucial that policies to meet major global challenges use scientific evidence, we discuss the socio-political difficulties and complexities that hinder this process. We discuss the necessity of embracing a broader view of what constitutes evidence—science and the evaluation of scientific evidence cannot be divorced from the political, cultural and social debate that inevitably and justifiably surrounds these major issues. As a pre-requisite for effective policy making, we propose a methodology that fully integrates scientific investigation with political debate and social discourse. We describe a rigorous process of mapping, analysis, visualisation and sharing of evidence, constructed from integrating science and social science data. This would then be followed by transparent evidence evaluation, combining independent assessment to test the validity and completeness of the evidence with deliberation to discover how the evidence is perceived, misunderstood or ignored. We outline the opportunities and the problems derived from the use of digital communications, including social media, in this methodology, and emphasise the power of creative and innovative evidence visualisation and sharing in shaping policy

Quantum Bayes rule

We state a quantum version of Bayes's rule for statistical inference and give a simple general derivation within the framework of generalized measurements. The rule can be applied to measurements on N copies of a system if the initial state of the N copies is exchangeable. As an illustration, we apply the rule to N qubits. Finally, we show that quantum state estimates derived via the principle of maximum entropy are fundamentally different from those obtained via the quantum Bayes rule.Comment: REVTEX, 9 page

Exploring New Drilling Prospects in the Southwest Pacific

A major International Ocean Discovery Program (IODP) workshop covering scientific ocean drilling in the southwest Pacific Ocean was held in Sydney, Australia, in late 2012. The workshop covered all fields of geoscience, and drilling targets in the area from the Equator to Antarctica. High-quality contributions and a positive and cooperative atmosphere ensured its success. The four science themes of the new IODP science plan were addressed. An additional resource-oriented theme considered possible co-investment opportunities involving IODP vessels. As a result of the workshop, existing proposals were revised and new ones written for the April 2013 deadline. Many of the proposals are broad and multidisciplinary in nature, hence broadening the scientific knowledge that can be produced by using the IODP infrastructure. This report briefly outlines the workshop and the related drilling plans

Nontransgenic models of breast cancer

Numerous models have been developed to address key elements in the biology of breast cancer development and progression. No model is ideal, but the most useful are those that reflect the natural history and histopathology of human disease, and allow for basic investigations into underlying cellular and molecular mechanisms. We describe two types of models: those that are directed toward early events in breast cancer development (hyperplastic alveolar nodules [HAN] murine model, MCF10AT human xenograft model); and those that seek to reflect the spectrum of metastatic disease (murine sister cell lines 67, 168, 4T07, 4T1). Collectively, these models provide cell lines that represent all of the sequential stages of progression in breast disease, which can be modified to test the effect of genetic changes

River research and applications across borders

Rivers flow across national borders, unfettered by political distinctions, and the ecological health of rivers is closely linked to their degree of connectivity. River research today is more global than it has ever been, but we show that river research, engineering, and management still operate within homegrown local paradigms. As a basis for this discussion, we studied the citation networks surrounding the most widely cited papers in our field, assessing the degree to which researchers have collaborated across geographical boundaries and fully drawn from the international literature. Despite gains over time, our field remains surprisingly and pervasively provincial. The likely explanation for provincial bias is that researchers are generally more familiar and comfortable with their own research methods, sites, and agendas. However, local focus has tangible consequences. For example, contrasting paradigms and differing approaches to river restoration and to flood-risk management show that opportunities are lost when we fail to learn from the successes and failures of other regions. As Sharp and Leshner (2014; p. 579) have argued, "the search for solutions needs to draw upon the talents and innovative ideas of scientists, engineers, and societal leaders worldwide to overcome traditional and nationalistic paradigms that have so far been inadequate to meeting these challenges.

Following a foraging fish-finder : diel habitat use of Blainville's beaked whales revealed by echolocation

© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 6 (2011): e28353, doi:10.1371/journal.pone.0028353.Simultaneous high resolution sampling of predator behavior and habitat characteristics is often difficult to achieve despite its importance in understanding the foraging decisions and habitat use of predators. Here we tap into the biosonar system of Blainville's beaked whales, Mesoplodon densirostris, using sound and orientation recording tags to uncover prey-finding cues available to echolocating predators in the deep-sea. Echolocation sounds indicate where whales search and encounter prey, as well as the altitude of whales above the sea-floor and the density of organisms around them, providing a link between foraging activity and the bio-physical environment. Tagged whales (n = 9) hunted exclusively at depth, investing most of their search time either in the lower part of the deep scattering layer (DSL) or near the sea-floor with little diel change. At least 43% (420/974) of recorded prey-capture attempts were performed within the benthic boundary layer despite a wide range of dive depths, and many dives included both meso- and bentho-pelagic foraging. Blainville's beaked whales only initiate searching when already deep in the descent and encounter prey suitable for capture within 2 min of the start of echolocation, suggesting that these whales are accessing prey in reliable vertical strata. Moreover, these prey resources are sufficiently dense to feed the animals in what is effectively four hours of hunting per day enabling a strategy in which long dives to exploit numerous deep-prey with low nutritional value require protracted recovery periods (average 1.5 h) between dives. This apparent searching efficiency maybe aided by inhabiting steep undersea slopes with access to both the DSL and the sea-floor over small spatial scales. Aggregations of prey in these biotopes are located using biosonar-derived landmarks and represent stable and abundant resources for Blainville's beaked whales in the otherwise food-limited deep-ocean.The work was funded by the Office of Naval Research and the National Ocean Partnership Program (US), by a consortium consisting of the Canary Islands Government, the Spanish Ministry of Environment and the Spanish Ministry of Defense, and by the European environmental funding LIFE-INDEMARES program for the inventory and designation of the Natura 2000 network in marine areas of the Spanish territory, headed by Fundacion Biodiversidad, with additional support from the Cabildo Insular of El Hierro. PA is currently supported by the National Research Project: Cetacean, Oceanography and Biodiversity from La Palma and El Hierro (CGL2009-13112) of the Spanish Ministry of Science and NAS by a Marie Curie fellowship from the 7th European Frame Program. MJ was supported by grants from the Strategic Environmental Research Development Program and from the National Ocean Partnership Program. PTM was supported by frame grants from the National Danish Science Foundation