66 research outputs found
Value Computations in Ventral Medial Prefrontal Cortex during Charitable Decision Making Incorporate Input from Regions Involved in Social Cognition
Little is known about the neural networks supporting value computation during complex social decisions. We investigated this question using functional magnetic resonance imaging while subjects made donations to different charities. We found that the blood oxygenation level-dependent signal in ventral medial prefrontal cortex (VMPFC) correlated with the subjective value of voluntary donations. Furthermore, the region of the VMPFC identified showed considerable overlap with regions that have been shown to encode for the value of basic rewards at the time of choice, suggesting that it might serve as a common valuation system during decision making. In addition, functional connectivity analyses indicated that the value signal in VMPFC might integrate inputs from networks, including the anterior insula and posterior superior temporal cortex, that are thought to be involved in social cognition
Resonances, and mechanisms of Theta-production
After explaining necessity of exotic hadrons, we discuss mechanisms which
could determine production of the exotic Theta-baryon. A possible important
role of resonances (producing the Theta in real or virtual decays) is
emphasized for various processes. Several experimental directions for studies
of such resonances, and the Theta itself, are suggested. We briefly discuss
also recent negative results on the Theta-baryon.Comment: 6 page
A study of pentaquarks on the lattice with overlap fermions
We present a quenched lattice QCD calculation of spin-1/2 five-quark states
with quark content for both positive and negative parities. We do
not observe any bound pentaquark state in these channels for either I = 0 or I
=1. The states we found are consistent with KN scattering states which are
checked to exhibit the expected volume dependence of the spectral weight. The
results are based on overlap-fermion propagators on two lattices, 12^3 x 28 and
16^3 x 28, with the same lattice spacing of 0.2 fm, and pion mass as low as ~
180 MeV.Comment: accepted for publication in Phys. Rev.
A New 76Ge Double Beta Decay Experiment at LNGS
This Letter of Intent has been submitted to the Scientific Committee of the
INFN Laboratori Nazionali del Gran Sasso (LNGS) in March 2004. It describes a
novel facility at the LNGS to study the double beta decay of 76Ge using an
(optionally active) cryogenic fluid shield. The setup will allow to scrutinize
with high significance on a short time scale the current evidence for
neutrinoless double beta decay of 76Ge using the existing 76Ge diodes from the
previous Heidelberg-Moscow and IGEX experiments. An increase in the lifetime
limit can be achieved by adding more enriched detectors, remaining thereby
background-free up to a few 100 kg-years of exposure.Comment: 67 pages, 19 eps figures, 17 tables, gzipped tar fil
The background in the neutrinoless double beta decay experiment GERDA
The GERmanium Detector Array (GERDA) experiment at the Gran Sasso underground
laboratory (LNGS) of INFN is searching for neutrinoless double beta decay of
76Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the
Q-value of the decay, Q_bb. To avoid bias in the signal search, the present
analysis does not consider all those events, that fall in a 40 keV wide region
centered around Q_bb. The main parameters needed for the neutrinoless double
beta decay analysis are described. A background model was developed to describe
the observed energy spectrum. The model contains several contributions, that
are expected on the basis of material screening or that are established by the
observation of characteristic structures in the energy spectrum. The model
predicts a flat energy spectrum for the blinding window around Q_bb with a
background index ranging from 17.6 to 23.8*10^{-3} counts/(keV kg yr). A part
of the data not considered before has been used to test if the predictions of
the background model are consistent. The observed number of events in this
energy region is consistent with the background model. The background at Q-bb
is dominated by close sources, mainly due to 42K, 214Bi, 228Th, 60Co and alpha
emitting isotopes from the 226Ra decay chain. The individual fractions depend
on the assumed locations of the contaminants. It is shown, that after removal
of the known gamma peaks, the energy spectrum can be fitted in an energy range
of 200 kev around Q_bb with a constant background. This gives a background
index consistent with the full model and uncertainties of the same size
Status of the GERDA experiment
The study of neutrinoless double beta (0nbb) decay is the only one presently known approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of 0nbb decay would prove that lepton number is not conserved, establish that neutrino has a Majorana component and, assuming that light neutrino is the dominating process, provide a method for the determination of its effective mass. GERDA is a new 0nbb decay experiment which is currently taking data at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy. It implements a new shielding concept by operating bare diodes made from Ge with enriched 76Ge in high purity liquid argon supplemented by a water shield. The aim of GERDA is to verify or refute the recent claim of discovery, and, in a second phase, to achieve a two orders of magnitude lower background index than past experiments, to increase the sensitive mass and to collect an exposure of 100 kg yr. The paper will discuss design, physics reach, and status of data taking of GERDA.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard
Value computations in ventral medial prefrontal cortex during charitable decision making incorporate input from regions involved in social cognition
Little is known about the neural networks supporting value computation during complex social decisions. We investigated this question using functional magnetic resonance imaging while subjects made donations to different charities. We found that the blood oxygenation level-dependent signal in ventral medial prefrontal cortex (VMPFC) correlated with the subjective value of voluntary donations. Furthermore, the region of the VMPFC identified showed considerable overlap with regions that have been shown to encode for the value of basic rewards at the time of choice, suggesting that it might serve as a common valuation system during decision making. In addition, functional connectivity analyses indicated that the value signal in VMPFC might integrate inputs from networks, including the anterior insula and posterior superior temporal cortex, that are thought to be involved in social cognition
Studying learning in games using eye-tracking
We report results from an exploratory study using eye-tracking recording of information acquisition
by players in a game theoretic learning paradigm. Eye-tracking is used to observe what
information subjects look at in 4×4 normal-form games; the eye-tracking results favor sophisticated
learning over adaptive learning and lend support to anticipatory or sophisticated models
of learning in which subjects look at payoffs of other players to anticipate what those players
might do. The decision data, however, are poorly fit by the simple anticipatory models we
examine. We discuss how eye-tracking studies of information acquisition can fit into research
agenda seeking to understand complex strategic behavior and consider methodological issues
that must be addressed in order to maximize their potential
Radiocarbon distribution and the effect of legacy in lakes of the McMurdo Dry Valleys, Antarctica
The water of the ice-covered lakes of the McMurdo Dry Valleys is derived primarily from glacial melt streams and to a lesser extent permafrost seeps and subglacial outflow. The result is a mixture of radiocarbon ages that reflect both the end-member water source and the biogeochemical processing of waters as they migrate to the lake-water column. Samples were collected from various locations within perennially ice-covered Antarctic lakes and the streams that feed them, and they were analyzed for radiocarbon abundance of organic and inorganic carbon. Stream gradient and length were shown to affect the degree of equilibration of water with the modern atmosphere prior to entering the lakes. Stream microbial mats assimilate inorganic carbon flowing over them. Seasonal ice-free \u27moat\u27 water dissolved inorganic carbon (DIC) is largely dependent on the amount of meltwater input from streams (modern) vs. that from direct glaciers input (old). Under the ice cover, 14C ages of lake-water DIC and organic matter are dependent on lake history, composition, and quantity of particulate matter fallout. Bottom waters of the west lobe of Lake Bonney have a DIC age of ~ 27,000 14C yr before present, which we believe are the most radiocarbon-deficient lake waters on Earth. Comparison of the radiocarbon profiles in the two lobes of Lake Bonney, along with previously published geochemical data, provides a new chronology of the evolution of these two waterbodies and shows that currently deep saline water is being displaced over the sill separating them. © 2014, by the Association for the Sciences of Limnology and Oceanography, Inc
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