60 research outputs found
On local-hidden-variable no-go theorems
The strongest attack against quantum mechanics came in 1935 in the form of a
paper by Einstein, Podolsky and Rosen. It was argued that the theory of quantum
mechanics could not be called a complete theory of Nature, for every element of
reality is not represented in the formalism as such. The authors then put forth
a proposition: we must search for a theory where, upon knowing everything about
the system, including possible hidden variables, one could make precise
predictions concerning elements of reality. This project was ultimatly doomed
in 1964 with the work of Bell Bell, who showed that the most general local
hidden variable theory could not reproduce correlations that arise in quantum
mechanics. There exist mainly three forms of no-go theorems for local hidden
variable theories. Although almost every physicist knows the consequences of
these no-go theorems, not every physicist is aware of the distinctions between
the three or even their exact definitions. Thus we will discuss here the three
principal forms of no-go theorems for local hidden variable theories of Nature.
We will define Bell inequalities, Bell inequalities without inequalities and
pseudo-telepathy. A discussion of the similarities and differences will follow.Comment: 7 pages, no figure, replaced "Bell inequalities" with "Bell theorems"
and updated the reference
Measurement-induced nonlocality based on the relative entropy
We quantify the measurement-induced nonlocality [Luo and Fu, Phys. Rev. Lett.
106, 120401 (2011)] from the perspective of the relative entropy. This
quantification leads to an operational interpretation for the
measurementinduced nonlocality, namely, it is the maximal entropy increase
after the locally invariant measurements. The relative entropy of nonlocality
is upper bounded by the entropy of the measured subsystem. We establish a
relationship between the relative entropy of nonlocality and the geometric
nonlocality based on the Hilbert- Schmidt norm, and show that it is equal to
the maximal distillable entanglement. Several trade-off relations are obtained
for tripartite pure states. We also give explicit expressions for the relative
entropy of nonlocality for Bell-diagonal states.Comment: 5 pages, 1 figures, version accepted Phys. Rev. A, PHYSICAL REVIEW A
85, 042325 (2012
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Introduction: microbes, networks, knowledge—disease ecology and emerging infectious diseases in time of COVID-19
This is an introduction to the topical collection Microbes, Networks, Knowledge: Disease Ecology in the twentieth Century, based on a workshop held at Queen Mary, University London on July 6–7 2016. More than twenty years ago, historian of science and medicine Andrew Mendelsohn asked, “Where did the modern, ecological understanding of epidemic disease come from?” Moving beyond Mendelsohn’s answer, this collection of new essays considers the global history of disease ecology in the past century and shows how epidemics and pandemics have made “microbes complex”
Inhibition of the Nuclear Import of Cubitus Interruptus by Roadkill in the Presence of Strong Hedgehog Signal
Hedgehog (Hh) signalling plays an important role in various developmental processes by activating the Cubitus interruptus (Ci)/Glioblastoma (Gli) family of transcription factors. In the process of proper pattern formation, Ci activity is regulated by multiple mechanisms, including processing, trafficking, and degradation. However, it remains elusive how Ci distinctly recognizes the strong and moderate Hh signals. Roadkill (Rdx) induces Ci degradation in the anterior region of the Drosophila wing disc. Here, we report that Rdx inhibited Ci activity by two different mechanisms. In the region abutting the anterior/posterior boundary, which receives strong Hh signal, Rdx inhibited the nuclear import of Ci by releasing importin α3 from Ci. In this region, Rdx negatively regulated the expression of transcription factor Knot/Collier. In farther anterior regions receiving moderate levels of Hh signal, Rdx induced Ci degradation, as reported previously. Thus, two different mechanisms by which Rdx negatively regulates Ci may play an important role in the fine-tuning of Hh responses
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'Tipping the Balance': Karl Friedrich Meyer, Latent Infections, and the Birth of Modern Ideas of Disease Ecology
The Swiss-born medical researcher Karl Friedrich Meyer (1884–1974) is best known as a ‘microbe hunter’ who pioneered investigations into diseases at the intersection of animal and human health in California in the 1920s and 1930s. In particular, historians have singled out Meyer’s 1931 Ludwig Hektoen Lecture in which he described the animal kingdom as a ‘reservoir of disease’ as a forerunner of ‘one medicine’ approaches to emerging zoonoses. In so doing, however, historians risk overlooking Meyer’s other intellectual contributions. Developed in a series of papers from the mid-1930s onwards, these were ordered around the concept of latent infections and sought to link microbial behavior to broader bio-ecological, environmental, and social factors that impact hostpathogen interactions. In this respect Meyer—like the comparative pathologist Theobald Smith and the immunologist Frank Macfarlane Burnet—can be seen as a pioneer of modern ideas of disease ecology. However, while Burnet’s and Smith’s contributions to this scientific field have been widely acknowledged, Meyer’s have been largely ignored. Drawing on Meyer’s published writings and private correspondence, this paper aims to correct that lacuna while contributing to a reorientation of the historiography of bacteriological epidemiology. In particular I trace Meyer’s intellectual exchanges with Smith, Burnet and the animal ecologist Charles Elton, over brucellosis, psittacosis and plague—exchanges that not only showed how environmental and ecological conditions could ‘tip the balance’ in favor of parasites but which transformed Meyer thinking about resistance to infection and disease
R497K polymorphism in epidermal growth factor receptor gene is associated with the risk of acute coronary syndrome
<p>Abstract</p> <p>Background</p> <p>Previous studies suggested that genetic polymorphisms in the epidermal growth factor receptor (EGFR) gene had been implicated in the susceptibility to some tumors and inflammatory diseases. EGFR has been recently implicated in vascular pathophysiological processes associated with excessive remodeling and atherosclerosis. Acute coronary syndrome (ACS) is a clinical manifestation of preceding atherosclerosis. Our purpose was to investigate the association of the EGFR polymorphism with the risk of ACS. In this context, we analyzed the HER-1 R497K and EGFR intron 1 (CA)<sub>n </sub>repeat polymorphisms in 191 patients with ACS and 210 age- and sex-matched controls in a Chinese population, using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) strategy and direct sequencing.</p> <p>Results</p> <p>There were significant differences in the genotype and allele distribution of R497K polymorphism of the EGFR gene between cases and controls. The <it>Lys </it>allele had a significantly increased risk of ACS compared with the <it>Arg </it>allele (adjusted OR = 1.49, 95% CI: 1.12–1.98, adjusted <it>P </it>= 0.006). However, no significant relationship between the number of (CA)<sub>n </sub>repeats of EGFR intron 1 (both alleles < 20 or any allele ≥ 20) and the risk of ACS was observed (adjusted OR = 0.97, 95% CI: 0.58–1.64, adjusted <it>P </it>= 0.911). Considering these two polymorphisms together, there was no statistically significant difference between the two groups.</p> <p>Conclusion</p> <p>R497K polymorphism of the EGFR gene is significantly associated with the risk of ACS. Our data suggests that R497K polymorphism may be used as a genetic susceptibility marker of the ACS.</p
The Janus head of Bachelard’s phenomenotechnique: from purification to proliferation and back
The work of Gaston Bachelard is known for two crucial concepts, that of the epistemological rupture and that of phenomenotechnique. A crucial question is, however, how these two concepts relate to one another. Are they in fact essentially connected or must they be seen as two separate elements of Bachelard's thinking? This paper aims to analyse the relation between these two Bachelardian moments and the significance of the concept of phenomenotechnique for today. This will be done by examining certain historical uses of the concepts of Bachelard have been used from the 1960s on. From this historical perspective, one gets the impression that these two concepts are relatively independent from each other. The Althusserian school has exclusively focused on the concept of 'epistemological break', while scholars from Science & Technology Studies (STS), such as Bruno Latour, seem to have only taken up the concept of phenomenotechnique. It in fact leads to two different models of how to think about science, namely the model of purification and the model of proliferation. The former starts from the idea that sciences are rational to the extent that they are purified and free from (epistemological) obstacles. Scientific objectivity, within this later model, is not achieved by eradicating all intermediaries, obstacles and distortions, but rather exactly by introducing as many relevant technical mediators as possible. Finally, such a strong distinction will be criticized and the argument will be made that both in Bachelard's and Latour's thought both concepts are combined. This leads to a janus-headed view on science, where both the element of purification (the epistemological break) and the element of proliferation (phenomenotechnique) are combine
Scientific revolutions, specialization and the discovery of the structure of DNA: toward a new picture of the development of the sciences
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