806 research outputs found
A selected history of expectation bias in physics
The beliefs of physicists can bias their results towards their expectations
in a number of ways. We survey a variety of historical cases of expectation
bias in observations, experiments, and calculations.Comment: 6 pages, 2 figure
Linking the subcultures of physics: Virtual empiricism and the bonding role of trust
This article draws on empirical material concerning the communication and use of knowledge in experimental physics and their relations to the culture of theoretical physics. The role that trust plays in these interactions is used to create a model of social distance between interacting theoretical and experimental cultures. This article thus seeks to reintroduce trust as a fundamental element in answering the problem of disunity in the sociology of knowledge
Complex Systems Science: Dreams of Universality, Reality of Interdisciplinarity
Using a large database (~ 215 000 records) of relevant articles, we
empirically study the "complex systems" field and its claims to find universal
principles applying to systems in general. The study of references shared by
the papers allows us to obtain a global point of view on the structure of this
highly interdisciplinary field. We show that its overall coherence does not
arise from a universal theory but instead from computational techniques and
fruitful adaptations of the idea of self-organization to specific systems. We
also find that communication between different disciplines goes through
specific "trading zones", ie sub-communities that create an interface around
specific tools (a DNA microchip) or concepts (a network).Comment: Journal of the American Society for Information Science and
Technology (2012) 10.1002/asi.2264
The Peaceful Atom Comes to Campus
Youthful idealism, institutional ambition, and Cold War sensibilities all helped shape the Michigan MemorialâPhoenix Project, the University of Michiganâs tribute to fallen World War II soldiers.</jats:p
Identifying adequate models in physico-mathematics: Descartes' analysis of the rainbow
The physico-mathematics that emerged at the beginning of the seventeenth century entailed the quantitative analysis of the physical nature with optics, meteorology and hydrostatics as its main subjects. Rather than considering physico-mathematics as the mathematization of natural philosophy, it can be characterized it as the physicalization of mathematics, in particular the subordinate mixed mathematics. Such transformation of mixed mathematics was a process in which physico-mathematics became liberated from Aristotelian constraints. This new approach to natural philosophy was strongly influenced by Jesuit writings and experimental practices. In this paper we will look at the strategies in which models were selected from the mixed sciences, engineering and technology adequate for an analysis of the specific phenomena under investigation. We will discuss Descartesâ analysis of the rainbow in the eight discourse of his Meteorology as an example of carefully selected models for physico-mathematical reasoning. We will further demonstrate that these models were readily available from Jesuit education and literature
Generations of interdisciplinarity in bioinformatics
Bioinformatics, a specialism propelled into relevance by the Human Genome
Project and the subsequent -omic turn in the life science, is an
interdisciplinary field of research. Qualitative work on the disciplinary
identities of bioinformaticians has revealed the tensions involved in work in
this âborderland.â As part of our ongoing work on the emergence of
bioinformatics, between 2010 and 2011, we conducted a survey of United
Kingdom-based academic bioinformaticians. Building on insights drawn
from our fieldwork over the past decade, we present results from this survey
relevant to a discussion of disciplinary generation and stabilization. Not only
is there evidence of an attitudinal divide between the different disciplinary
cultures that make up bioinformatics, but there are distinctions between the
forerunners, founders and the followers; as inter/disciplines mature, they face
challenges that are both inter-disciplinary and inter-generational in nature
The HPS experiment at JLab
Many Beyond-Standard-Model theories predict a new massive gauge boson, such as a âdarkâ or âheavy photonâ. The heavy photon is expected to mix with the Standard Model photon through kinetic mixing and therefore have a small coupling to electric charge. The Heavy Photon Search (HPS) experiment is searching for a heavy photon at the Thomas Jefferson National Accelerator Facility (JLab), in the mass range 20-500 MeV/c2. In particular HPS looks for the e+eâ decay channel of heavy photons radiated by electron Bremsstrahlung, employing both an invariant mass search and detached vertexing techniques. The experiment employs a compact forward spectrometer comprising silicon microstrip detectors for vertexing and tracking and an electromagnetic calorimeter for particle identification and triggering. HPS took data successfully in 2015 and 2016 at 1.05 GeV and 2.3 GeV beam energies, respectively. First results are expected to be presented soon
Magnetization Dynamics, Gyromagnetic Relation, and Inertial Effects
The gyromagnetic relation - i.e. the proportionality between the angular
momentum (defined by an inertial tensor) and the magnetization - is evidence of the intimate connections between the magnetic properties
and the inertial properties of ferromagnetic bodies. However, inertia is absent
from the dynamics of a magnetic dipole (the Landau-Lifshitz equation, the
Gilbert equation and the Bloch equation contain only the first derivative of
the magnetization with respect to time). In order to investigate this
paradoxical situation, the lagrangian approach (proposed originally by T. H.
Gilbert) is revisited keeping an arbitrary nonzero inertial tensor. A dynamic
equation generalized to the inertial regime is obtained. It is shown how both
the usual gyromagnetic relation and the well-known Landau-Lifshitz-Gilbert
equation are recovered at the kinetic limit, i.e. for time scales above the
relaxation time of the angular momentum.Comment: 10 pages, 1 figur
Nonexotic Neutral Gauge Bosons
We study theoretical and experimental constraints on electroweak theories
including a new color-singlet and electrically-neutral gauge boson. We first
note that the electric charges of the observed fermions imply that any such Z'
boson may be described by a gauge theory in which the Abelian gauge groups are
the usual hypercharge along with another U(1) component in a kinetic-diagonal
basis. Assuming that the observed quarks and leptons have
generation-independent U(1) charges, and that no new fermions couple to the
standard model gauge bosons, we find that their U(1) charges form a
two-parameter family consistent with anomaly cancellation and viable fermion
masses, provided there are at least three right-handed neutrinos. We then
derive bounds on the Z' mass and couplings imposed by direct production and
Z-pole measurements. For generic charge assignments and a gauge coupling of
electromagnetic strength, the strongest lower bound on the Z' mass comes from
Z-pole measurements, and is of order 1 TeV. If the new U(1) charges are
proportional to B-L, however, there is no tree-level mixing between the Z and
Z', and the best bounds come from the absence of direct production at LEPII and
the Tevatron. If the U(1) gauge coupling is one or two orders of magnitude
below the electromagnetic one, these bounds are satisfied for most values of
the Z' mass.Comment: 26 pages, 2 figures. A comparison with the LEP bounds on sneutrino
resonances is include
Knowledge politics and new converging technologies: a social epistemological perspective
The ânew converging technologiesâ refers to the prospect of advancing the human condition by the integrated study and application of nanotechnology, biotechnology, information technology and the cognitive sciences - or âNBICâ. In recent years, it has loomed large, albeit with somewhat different emphases, in national science policy agendas throughout the world. This article considers the political and intellectual sources - both historical and contemporary - of the converging technologies agenda. Underlying it is a fluid conception of humanity that is captured by the ethically challenging notion of âenhancing evolutionâ
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