3,142 research outputs found
Even tiers and resonances on the Real Projective Plane
In this work we focus on various phenomenological aspects of the lightest
even tiers, (2,0) and (0,2), in models based on a Real Projective Plane in 6
dimensions. We discuss the spectrum of the levels due to loop corrections, and
the limit when the two radii are equal, in which case the two levels mix with
each other and a new basis is defined. We also discuss the dependence of the
spectrum on the ratio of the two radii. These results are essential to
understand the phenomenology of the model at colliders (LHC) and to predict the
relic abundance of Dark Matter. Finally, we estimate the bounds on the radius
from resonant decays of the even tiers at the LHC, showing that they can be in
the 600 GeV range after the complete analysis of the 2011 data.Comment: 43 pages, 10 figure
Dark Matter from Lorentz Invariance and the LHC
International audienceIn extra dimensional models, a Dark Matter candidate can be present thanks to a Kaluza-Klein parity which makes the lightest resonances stable. However, compactifications considered sofar need the symmetry to be imposed by hand on the model: here we propose the unique orbifold in 6 dimensions where such parity arises naturally as part of the unbroken 6D Lorentz invariance. As an example we introduce a model of universal extra dimensions where all standard model fields propagate in the extra dimensions. The dark matter candidate is a scalar photon and its preferred mass range lies below 300 GeV. Due to the small splitting between states in the same Kaluza-Klein tier, discovery of the lightest tiers is challenging at the LH
Building Detection by Dempster-Shafer Fusion of LIDAR Data and Multispectral Aerial Imagery
A method for the classification of land cover in urban areas by the fusion of first and last pulse LIDAR data and multi-spectral images is presented. Apart from buildings, the classes "tree", "grass land", and "bare soil" are also distinguished by a classification method based on the theory of Dempster-Shafer for data fusion. Examples are given for a test site in Germany
Investigation of the skeletal muscle transcriptome in lambs fed β adrenergic agonists and subjected to heat stress for 21 d
Dietary β-adrenergic agonists (β-AA) are used in livestock to increase muscle protein accretion and decrease adipose deposition during the last 20 to 40 d of the finishing period (Johnson et al., 2014). These β-AA act through specific seven transmembrane receptors and are classified by the receptor isoform to which they primarily bind (Mersmann, 1998). Two β-AA are approved for use in beef cattle in the United States: ractopamine HCl (RAC, β1 agonist) and zilpaterol HCl (ZH, β2 agonist) (Johnson et al., 2014). Supplementation of β-AA increases efficiency of the animal and results in a leaner carcass (Elam et al., 2009). However, the skeletal muscle’s genomic response to these treatments is not well understood. Heat stress (HS) has long been a major concern in the livestock industry. HS occurs when an animal’s body temperature rises above its thermoneutral zone, at which point the heat load exceeds the animal’s capacity for heat dissipation (Bernabucci et al., 2010), resulting in decreased feed intake and poor performance (Marai et al., 2007). Therefore, growth and production decrease during HS, affecting economically important carcass and reproductive traits. As a result, millions of dollars are lost each year due to HS (Renaudeau et al., 2012). Individually, HS and β-AA supplementation have antagonistic effects on muscle growth. However, there is a gap in understanding of the genomic mechanisms through which animals respond to these factors individually and in concert. The purpose of this study is to investigate the effects of β-AA, HS, and their interaction in skeletal muscle using transcriptomic analyses
The evolution of deep water mixing and weathering inputs in the central Atlantic Ocean over the past 33 Myr
The isotopic composition of Nd in present-day deep waters of the central and northeastern Atlantic Ocean is
thought to fingerprint mixing of North Atlantic Deep Water with Antarctic Bottom Water. The central Atlantic
Romanche and Vema Fracture Zones are considered the most important pathways for deep water exchange
between the western and eastern Atlantic basins today. We present new Nd isotope records of the deepwater
evolution in the fracture zones obtained from ferromanganese crusts, which are inconsistent with simple water
mass mixing alone prior to 3 Ma and require additional inputs from other sources. The new Pb isotope time
series from the fracture zones are inexplicable by simple mixing of North Atlantic Deep Water and Antarctic
Bottom Water for the entire past 33 Myr. The distinct and relatively invariable Nd and Pb isotope records of
deep waters in the fracture zones appear instead to have been controlled to a large extent by contributions from
Saharan dust and the Orinoco/Amazon Rivers. Thus the previously observed similarity of Nd and Pb isotope
time series from the western and eastern North Atlantic basins is better explainable by direct supply of Labrador
Seawater to the eastern basin via a northern pathway rather than by advection of North Atlantic Deep Water via
the Romanche and Vema Fracture Zones
Operationalizing anthropological theory: four techniques to simplify networks of co-occurring ethnographic codes
The use of data and algorithms in the social sciences allows for exciting progress, but also poses epistemological challenges. Operations that appear innocent and purely technical may profoundly influence final results. Researchers working with data can make their process less arbitrary and more accountable by making theoretically grounded methodological choices. We apply this approach to the problem of simplifying networks representing ethnographic corpora, in the interest of visual interpretation. Network nodes represent ethnographic codes, and their edges the co-occurrence of codes in a corpus. We introduce and discuss four techniques to simplify such networks and facilitate visual analysis. We show how the mathematical characteristics of each one are aligned with an identifiable approach in sociology or anthropology: structuralism and post-structuralism; identifying the central concepts in a discourse; and discovering hegemonic and counter-hegemonic clusters of meaning. We then provide an example of how the four techniques complement each other in ethnographic analysis
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