1,396 research outputs found
Towards a Conceptualization of Sociomaterial Entanglement
In knowledge representation, socio-technical systems can be modeled
as multiagent systems in which the local knowledge of each individual agent can
be seen as a context. In this paper we propose formal ontologies as a means to
describe the assumptions driving the construction of contexts as local theories and
to enable interoperability among them. In particular, we present two alternative
conceptualizations of the notion of sociomateriality (and entanglement), which
is central in the recent debates on socio-technical systems in the social sciences,
namely critical and agential realism.
We thus start by providing a model of entanglement according to the critical realist
view, representing it as a property of objects that are essentially dependent on
different modules of an already given ontology. We refine then our treatment by
proposing a taxonomy of sociomaterial entanglements that distinguishes between
ontological and epistemological entanglement. In the final section, we discuss the
second perspective, which is more challenging form the point of view of knowledge
representation, and we show that the very distinction of information into
modules can be at least in principle built out of the assumption of an entangled
reality
Singularities of -fold integrals of the Ising class and the theory of elliptic curves
We introduce some multiple integrals that are expected to have the same
singularities as the singularities of the -particle contributions
to the susceptibility of the square lattice Ising model. We find
the Fuchsian linear differential equation satisfied by these multiple integrals
for and only modulo some primes for and , thus
providing a large set of (possible) new singularities of the . We
discuss the singularity structure for these multiple integrals by solving the
Landau conditions. We find that the singularities of the associated ODEs
identify (up to ) with the leading pinch Landau singularities. The second
remarkable obtained feature is that the singularities of the ODEs associated
with the multiple integrals reduce to the singularities of the ODEs associated
with a {\em finite number of one dimensional integrals}. Among the
singularities found, we underline the fact that the quadratic polynomial
condition , that occurs in the linear differential equation
of , actually corresponds to a remarkable property of selected
elliptic curves, namely the occurrence of complex multiplication. The
interpretation of complex multiplication for elliptic curves as complex fixed
points of the selected generators of the renormalization group, namely
isogenies of elliptic curves, is sketched. Most of the other singularities
occurring in our multiple integrals are not related to complex multiplication
situations, suggesting an interpretation in terms of (motivic) mathematical
structures beyond the theory of elliptic curves.Comment: 39 pages, 7 figure
Evidence for the Role of Instantons in Hadron Structure from Lattice QCD
Cooling is used as a filter on a set of gluon fields sampling the Wilson
action to selectively remove essentially all fluctuations of the gluon field
except for the instantons. The close agreement between quenched lattice QCD
results with cooled and uncooled configurations for vacuum correlation
functions of hadronic currents and for density-density correlation functions in
hadronic bound states provides strong evidence for the dominant role of
instantons in determining light hadron structure and quark propagation in the
QCD vacuum.Comment: 26 pages in REVTeX, plus 10 figures, uuencoded. Submitted to Physical
Review D. MIT-CTP-226
Pion structure from improved lattice QCD: form factor and charge radius at low masses
The charge form factor of the pion is calculated in lattice QCD. The
non-perturbatively improved Sheikholeslami-Wohlert action is used together with
the improved vector current. Other choices for the current are
examined. The form factor is extracted for pion masses from 970 MeV down to 360
MeV and for momentum transfers . The mean square
charge radius is extracted, compared to previous determinations and its
extrapolation to lower masses discussed.Comment: 12 pages REVTeX, 15 figures. Designation of currents clarified.
Details concerning extraction of parameters added. Version accepted by Phys.
Rev.
The Strongly Coupled 't Hooft Model on the Lattice
We study the strong coupling limit of the one-flavor and two-flavor massless
't Hooft models, -color , on a lattice. We use
staggered fermions and the Hamiltonian approach to lattice gauge theories. We
show that the one-flavor model is effectively described by the
antiferromagnetic Ising model, whose ground state is the vacuum of the gauge
model in the infinite coupling limit; expanding around this ground state we
derive a strong coupling expansion and compute the lowest lying hadron masses
as well as the chiral condensate of the gauge theory. Our lattice computation
well reproduces the results of the continuum theory. Baryons are massless in
the infinite coupling limit; they acquire a mass already at the second order in
the strong coupling expansion in agreement with the Witten argument that
baryons are the solitons.
The spectrum and chiral condensate of the two-flavor model are effectively
described in terms of observables of the quantum antiferromagnetic Heisenberg
model. We explicitly write the lowest lying hadron masses and chiral condensate
in terms of spin-spin correlators on the ground state of the spin model. We
show that the planar limit () of the gauge
model corresponds to the large spin limit () of the
antiferromagnet and compute the hadron mass spectrum in this limit finding
that, also in this model, the pattern of chiral symmetry breaking of the
continuum theory is well reproduced on the lattice.Comment: LaTex, 25 pages, no figure
HAEMATOLOGICAL CHANGES INDUCED BY SHORT - TERM EXPOSURE TO COPPER IN THE INDIAN FRESHWATER FISH, NOTOPTERUS NOTOPTERUS (PALLAS)
The normal ranges of blood chemistry and the effect of copper sulfate was studied in Indian fresh water fish, Notopterus notopterus. The blood serum biochemical components like, hemoglobin, proteins, urea, urea nitrogen, cholesterol, and glucose levels were determined during the phase of reproductive cycle. Toxic level (LC50) of copper sulfate was found to be 30ppm. Under this concentration (30ppm) after exposure to 96hr the haematological parameters such as glucose, protein, urea, urea nitrogen, cholesterol, creatinine and haemoglobin content were estimated in the blood serum. A significant decrease (p < 0.001) in the biochemical profile such as protein, glucose, urea, urea nitrogen and creatinine were observed; where as haemoglobin (p < 0.001) and cholesterol (p < 0.01) levels in the blood of exposed group was significantly (p < 0.001) higher than that of the control group. The results suggest that the reduction in the above biochemical levels of blood serum may be because of stress due to copper concentration
Bodies, technologies and action possibilities: when is an affordance?
Borrowed from ecological psychology, the concept of affordances is often said to offer the social study of technology a means of re-framing the question of what is, and what is not, ‘social’ about technological artefacts. The concept, many argue, enables us to chart a safe course between the perils of technological determinism and social constructivism. This article questions the sociological adequacy of the concept as conventionally deployed. Drawing on ethnographic work on the ways technological artefacts engage, and are engaged by, disabled bodies, we propose that the ‘affordances’ of technological objects are not reducible to their material constitution but are inextricably bound up with specific, historically situated modes of engagement and ways of life
Image Classification using Textural Neural Networks
This paper presents backpropagation neural networks that utilize texture information to accurately classify photographic images. Training with minimum sets is shown to yield excellent results
‘The past was never simply there to begin with and the future is not simply what will unfold’ : a posthumanist performative approach to qualitative longitudinal research
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