4,721 research outputs found
Impossible shadows and lightness constancy
The intersection between an illumination and a reflectance edge is characterised by the
`ratio-invariant' property, that is the luminance ratio of the regions under different illumination
remains the same.
In a CRT experiment, we shaped two areas, one surrounding the other, and simulated
an illumination edge dividing them in two frames of illumination. The portion of the illumina-
tion edge standing on the surrounding area (labelled contextual background) was the contextual
edge, while the portion standing on the enclosed area (labelled mediating background) was the
mediating edge. On the mediating background, there were two patches, one per illumination
frame. Observers were asked to adjust the luminance of the patch in bright illumination to
equate the lightness of the other. We compared conditions in which the luminance ratio at the
contextual edge could be (i) equal (possible shadow), or (ii) larger (impossible shadow) than
that at the mediating edge. In addition, we manipulated the reflectance of the backgrounds.
It could be higher for the contextual than for the mediating background; or, vice versa, lower
for the contextual than for the mediating background. Results reveal that lightness constancy
significantly increases when: (i) the luminance ratio at the contextual edge is larger than that at
the mediating edge creating an impossible shadow, and (ii) the reflectance of the contextual
background is lower than that of the mediating one. We interpret our results according to the
albedo hypothesis, and suggest that the scission process is facilitated when the luminance ratio
at the contextual edge is larger than that at the mediating edge and/or the reflectance of the
including area is lower than that of the included one. This occurs even if the ratio-invariant
property is violated
TL1A/DR3 axis involvement in the inflammatory cytokine network during pulmonary sarcoidosis
BACKGROUND:
TNF-like ligand 1A (TL1A), a recently recognized member of the TNF superfamily, and its death domain receptor 3 (DR3), firstly identified for their relevant role in T lymphocyte homeostasis, are now well-known mediators of several immune-inflammatory diseases, ranging from rheumatoid arthritis to inflammatory bowel diseases to psoriasis, whereas no data are available on their involvement in sarcoidosis, a multisystemic granulomatous disease where a deregulated T helper (Th)1/Th17 response takes place.
METHODS:
In this study, by flow cytometry, real-time PCR, confocal microscopy and immunohistochemistry analyses, TL1A and DR3 were investigated in the pulmonary cells and the peripheral blood of 43 patients affected by sarcoidosis in different phases of the disease (29 patients with active sarcoidosis, 14 with the inactive form) and in 8 control subjects.
RESULTS:
Our results demonstrated a significant higher expression, both at protein and mRNA levels, of TL1A and DR3 in pulmonary T cells and alveolar macrophages of patients with active sarcoidosis as compared to patients with the inactive form of the disease and to controls. In patients with sarcoidosis TL1A was strongly more expressed in the lung than the blood, i.e., at the site of the involved organ. Additionally, zymography assays showed that TL1A is able to increase the production of matrix metalloproteinase 9 by sarcoid alveolar macrophages characterized, in patients with the active form of the disease, by reduced mRNA levels of the tissue inhibitor of metalloproteinase (TIMP)-1.
CONCLUSIONS:
These data suggest that TL1A/DR3 interactions are part of the extended and complex immune-inflammatory network that characterizes sarcoidosis during its active phase and may contribute to the pathogenesis and to the progression of the disease
Managing variability in decision making in swine growing-finishing units
peer-reviewedAnalysis of data collected from pig farms may be useful to understand factors affecting pig health and productive performance. However, obtaining these data and drawing conclusions from them can be done at different levels and presents several challenges. In the present study, information from 688 batches of growing-finishing (GF) pigs (average initial and final body weight of 19.1 and 108.5 kg respectively) from 404 GF farms integrated in 7 companies was obtained between July 2008 and July 2010 in Spain by survey. Management and facility factors associated with feed conversion ratio (FCR) and mortality were studied by multiple linear regression analysis in each single company (A to G) and in an overall database (OD). Factors studied were geographic location of the farm, trimester the pigs entered the farm, breed of sire and sex segregation in pens (BREGENSEG), use of circovirus vaccine, number of origins the pigs were obtained from, age of the farm, percentage of slatted floor, type of feeder, drinker and ventilation, number of phases and form of feed, antibiotic administration system, water source, and number and initial weight of pigs.
Results
In two or more companies studied and/or in OD, the trimester when pigs were placed in the farm, BREGENSEG, number of origins of the pigs, age of the farm and initial body weight were factors associated with FCR. Regarding mortality, trimester of placement, number of origins of the pigs, water source in the farm, number of pigs placed and the initial body weight were relevant factors. Age of the farm, antibiotic administration system, and water source were only provided by some of the studied companies and were not included in the OD model, however, when analyzed in particular companies these three variables had an important effect and may be variables of interest in companies that do not record them.
Conclusions
Analysing data collected from farms at different levels helps better understand factors associated with productive performance of pig herds. Out of the studied factors trimester of placement and number of origins of the pigs were the most relevant factors associated with FCR and mortality.This research was supported by the Spanish Ministerio de Ciencia e Innovación (project AGL2011-29960). We also thank the Agencia Española de Cooperación Internacional para el Desarrollo (MAEC-AECID) for research fellowship
About the parabolic relation existing between the skewness and the kurtosis in time series of experimental data
In this work we investigate the origin of the parabolic relation between
skewness and kurtosis often encountered in the analysis of experimental
time-series. We argue that the numerical values of the coefficients of the
curve may provide informations about the specific physics of the system
studied, whereas the analytical curve per se is a fairly general consequence of
a few constraints expected to hold for most systems.Comment: To appear in Physica Script
Covariant formulation of Noether's Theorem for translations on kappa-Minkowski spacetime
The problem of finding a formulation of Noether's theorem in noncommutative
geometry is very important in order to obtain conserved currents and charges
for particles in noncommutative spacetimes. In this paper, we formulate
Noether's theorem for translations of kappa-Minkowski noncommutative spacetime
on the basis of the 5-dimensional kappa-Poincare' covariant differential
calculus. We focus our analysis on the simple case of free scalar theory. We
obtain five conserved Noether currents, which give rise to five energy-momentum
charges. By applying our result to plane waves it follows that the
energy-momentum charges satisfy a special-relativity dispersion relation with a
generalized mass given by the fifth charge. In this paper we provide also a
rigorous derivation of the equation of motion from Hamilton's principle in
noncommutative spacetime, which is necessary for the Noether analysis.Comment: LateX, 24 pages. This version includes the analysis of the case of
massive fiel
A symmetry invariant integral on kappa-deformed spacetime
In this note we present an approach using both constructive and Hopf
algebraic methods to contribute to the not yet fully satisfactory definition of
an integral on kappa-deformed spacetime. The integral presented here is based
on the inner product of differential forms and it is shown that this integral
is explicitly invariant under the deformed symmetry structure.Comment: 16 page
The MGDO software library for data analysis in Ge neutrinoless double-beta decay experiments
The GERDA and Majorana experiments will search for neutrinoless double-beta
decay of germanium-76 using isotopically enriched high-purity germanium
detectors. Although the experiments differ in conceptual design, they share
many aspects in common, and in particular will employ similar data analysis
techniques. The collaborations are jointly developing a C++ software library,
MGDO, which contains a set of data objects and interfaces to encapsulate, store
and manage physical quantities of interest, such as waveforms and high-purity
germanium detector geometries. These data objects define a common format for
persistent data, whether it is generated by Monte Carlo simulations or an
experimental apparatus, to reduce code duplication and to ease the exchange of
information between detector systems. MGDO also includes general-purpose
analysis tools that can be used for the processing of measured or simulated
digital signals. The MGDO design is based on the Object-Oriented programming
paradigm and is very flexible, allowing for easy extension and customization of
the components. The tools provided by the MGDO libraries are used by both GERDA
and Majorana.Comment: 4 pages, 1 figure, proceedings for TAUP201
Probing the mechanism of neutrinoless double-beta decay in multiple isotopes
A large experimental program is being mounted to search for neutrinoless double-beta decay over the next decade. Multiple experiments using different target isotopes are being prepared to explore the whole parameter space allowed for inverted-ordered light neutrinos, and have the potential to make discoveries in several other scenarios, including normal-ordered light neutrinos and other exotic mechanisms. We investigate to what extent long-range and exotic short-range contributions may be distinguished by combining measurements of the decay half-life across isotopes in the framework of a global Bayesian analysis. We demonstrate how measurements in two isotopes will constrain the parameter space up to a two-fold degeneracy, and how a further measurement in a third isotope removes such a degeneracy. We also discuss the impact of uncertainties and correlations in nuclear matrix element calculations. Our work motivates an experimental program measuring neutrinoless double-beta decay in more than one isotope, as this would break parameter degeneracies and advance our understanding of particle physics beyond the Standard Model
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